Note: Descriptions are shown in the official language in which they were submitted.
CA 02862041 2015-11-27
1
METHOD FOR PURIFYING ORGANIC DIPHOSPHITE COMPOUNDS
BACKGROUND OF THE INVENTION
The present invention relates to a method of purifying organic diphosphite
compounds.
PRIOR ART
Organic diphosphite compounds have found extremely widespread use, for example
as
chelating ligands in homogeneous catalysis, and also as flame retardants, UV
stabilizers,
etc. Particular rhodium complexes with organic diphosphite compounds have been
found
to be useful as catalysts for the hydroformylation of olefins since they
firstly have a high
catalytic activity and secondly lead predominantly to linear aldehydes which
are preferred
for many applications. Organic diphosphite compounds are also suitable as
ligands for
transition metal complex catalysts for hydrocyanation, hydrogenation,
carbonylation,
hydroacylation, hydroamidation, hydroesterification, hydrosilylation,
hydroboration,
alcoholysis, isomerization, allylic alkylation or hydroalkylation.
Such diphosphite compounds, their preparation and their use as ligands in a
hydroformylation process are described, for example, in EP 0 214 622 A2, US
4,668,651,
US 4,748,261, US 4,769,498, US 4,885,401, US 5,235,113, US 5,391,801, US
5,663,403,
US 5,728,861 and US 6,172,267. The use in a hydrocyanation process is also
described in
US 6,127,567.
Organic diphosphites of the general formula (A) are usually prepared by a
process
comprising the following steps:
a) reaction of a compound of the formula (A1) (= first aromatic diol)
with phosphorus
trichloride to give the phosphomonochloridite (A2)
CA 02862041 2015-11-27
2
RxnAi111,mia
OH
R.
0
PCI,
X X ¨P CI
- 2 HCI
o/
411k OH
Rxn
Rxn
(A1) (A2)
b) reaction of the phosphomonochloridite (A2) with a compound of the
formula (A3) (=
second aromatic diol) to give the chelating diphosphite (A)
Rxn
x Rxn
RxnAira /P -O
OH
wp 0
2 +
Fen, irt - 2 HCI 441 RYm
X P¨CI
o/ RYm
HO
()
Rx A3
n 1
(A2) Rxn 0
X SI
(A) IR%
The groups derived from the first aromatic diol (A1) in the organic
diphosphites will
hereinafter also be referred to as "side wings".
The preparation of diphosphites in which at least one of the phosphorus atoms
is not part
of a heterocycle is carried out analogously by, in step a), reacting P0I3 with
two molar
equivalents of an appropriate monoalcohol instead of one molar equivalent of
the first
aromatic diol (A1). To prepare diphosphites in which the two phosphorus atoms
are
bridged by other groups, other diols can be used instead of the backbone diol
(A3).
One possible way of removing the hydrogen halides liberated in the
condensation reaction
is the use of an at least stoichiometric amount of base, with nitrogen bases
frequently
CA 02862041 2015-11-27
3
being used. However, the removal of the resulting acid salts is frequently
difficult and the
salts can often not be recycled sensibly and have to be disposed of, which is
associated
with additional costs.
WO 2003/062171 and WO 2003/062251 describe a method of separating acids from
reaction mixtures by means of an auxiliary base which with the acid forms a
salt which is
liquid at temperatures at which the desired product is not significantly
decomposed during
removal of the liquid salt and the salt of the auxiliary base forms two
immiscible liquid
phases with the desired product or the solution of the desired product in a
suitable solvent.
In other words, the acid salts of the auxiliary base behave like ionic liquids
which are
essentially immiscible with the actual reaction solvent. Preferred auxiliary
bases of this
type are 1-methylimidazole, 1-n-butylimidazole, 2-methylpyridine and 2-
ethylpyridine. The
methods described in WO 2003/062171 and WO 2003/062251 are suitable, inter
alia, for
phosphorylation reactions such as the above-described synthesis of
phosphomonochloridites and the reaction thereof with an aromatic diol to give
a
diphosphite compound.
In general, organic diphosphite compounds have to be subjected after the
synthesis to a
purification in order to remove interfering impurities before use in a
catalysis process.
Potential impurities can be independent of the synthesis process used, e.g.
decomposition
or other subsequent products typical of this class of material or be formed
during the
course of the synthesis. Problematical impurities are, firstly, impurities
which can form
complexes with transition metals such as rhodium, e.g. acetonitrile, and thus
have a
potential influence on use of the diphosphite compounds as catalysts. These
include, for
example, secondary organophosphites which will be discussed in more detail
below. Also
problematical are impurities which make the use of expensive apparatuses
necessary, e.g.
corrosive halides, especially chloride. Chloride ions are also known catalyst
poisons for
rhodium complex catalysts.
Adverse effects of impurities in the organic diphosphite compounds can affect
the process
itself in which they are used as ligands. Thus, impurities which act as
catalyst poisons
and/or lead to decomposition of the catalyst have an adverse effect on the
catalyst
operating life, which can over time lead to operational malfunctions. This
applies, in
CA 02862041 2015-11-27
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particular, to the use of the organic diphosphite compounds in a continuous
process in
which impurities can accumulate. Adverse effects of these impurities can also
affect the
desired products produced in the respective process by having adverse effects
on product
properties, e.g. the storage behavior, the handleability, the odor, the color,
the keeping
qualities, etc.
The substantially complete removal of impurities is therefore a critical
prerequisite for the
organic diphosphite compound to be able to be used successfully in an
industrial process.
Typical impurities from the synthesis of organic diphosphite compounds are
residues of
the base (generally an organic nitrogen-comprising compound, e.g. an amine)
used for
scavenging the hydrogen halide (generally HCI) liberated in the reaction, the
acid salts of
this base and possibly also residues of the hydrogen halide. Typical
impurities from the
synthesis also include catalysts which are intended to accelerate the reaction
of the
phosphorus trihalide with the aromatic alcohols. Even when, as described in
WO 2003/062171 and WO 2003/062251, a compound whose acid salts behave like
ionic
liquids which are essentially immiscible with the solution of the organic
diphosphite
compound in an appropriate organic solvent, e.g. toluene, and can thus easily
be
separated off by phase separation is used as base, purification of the crude
ligand solution
is generally nevertheless absolutely necessary.
DE 103 60 771 A1 teaches carrying out the reaction of phosphorus halides with
organic
compounds which have at least one OH group in the presence of a basic ion-
exchange
resin.
WO 2009/120210 and the US patent 2009/0247790 of the same priority date
describe a
process for preparing phosphomonochloridites which can be used as intermediate
for
introducing the side wings in the preparation of chelating diphosphite
compounds.
According to these documents, the reaction of PCI3 with an aromatic diol
occurs in a
solution comprising less than 5 mol% of a nitrogen base, based on mol of
aromatic diol,
with HCI formed being driven from the reaction solution and the reaction being
carried out
under essentially isothermal conditions. However, this is associated with the
disadvantage
that hydrogen chloride gas discharged as offgas stream has to be isolated in a
separate
CA 02862041 2015-11-27
scrubber and disposed of. In addition, solvent is generally also discharged
with the offgas
stream. However, in order to avoid emissions, the solvent entrained in the
offgas has to be
removed, which can be effected, for example, by incineration and requires an
additional
outlay.
5
WO 2010/042313 describes a process for preparing organic diphosphites, in
which the
reaction of PCI3 with the first aromatic diol forming the side wings is
carried out in the
presence of the second aromatic diol which bridges the two phosphorus atoms
and the
reactants are brought into contact with one another as a slurry in an organic
solvent and
the slurry comprises less than 5 mor/0 of a nitrogen base, based on mol of
first diol, and
the organic solvent has only a slight solvent capacity for HCI. This procedure
leads to a
reduction in the amount of acid salts formed by scavenging of the HCI by means
of base in
the condensation reaction.
Once again, the hydrogen chloride gas discharged as offgas stream has to be
isolated and
disposed of.
WO 2010/052090 and WO 2010/052091 describe processes for preparing 6-
chlorodibenzo[d,f][1,3,2]dioxaphosphepin, which can be used as intermediate
for
introduction of the side wings in the preparation of chelating diphosphite
compounds. In
these processes, 2,2'-dihydroxybiphenyl suspended in an inert solvent is added
to an
excess of phosphorus trichloride under inert gas in a reactor with stirring
and the gases
formed are discharged from the reaction mixture. Thus, an addition of base in
the reaction
can be dispensed with. The hydrogen chloride discharged as offgas stream has
to be
collected, for which, according to the teachings of this document, a separate
scrubber is
used. However, to avoid emissions, the solvent entrained in the offgas has to
be removed,
which can, for example, be carried out by incineration and requires an
additional outlay.
Further impurities which can be comprised in the solution of the crude organic
diphosphite
are the monoxide (B1) and dioxide (B2) thereof or the hemiligand (B3) formed
by
incomplete reaction of the backbone.
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6
Rxn Rx
1.1 n
X 1110 X
0 le Rxn
0 (10 Rxn Rxn
\ 0
0= \ 1 X
0----`",
/P¨`-', =P
/
0 0
=RYm irt RYrn 0 0
Rxn
Wm. Wm. \
/
0
0 ¨P
Rx 0 ¨P= Wm
0 4400 R n.,
n 411111 \
0
Rxn 411 \
0 .
HO
X 411 X iiii
(B3)
Rxn Rxn
(B1) (B2)
In Chem. Eur. J. 2011, 17, 2120, A. Christiansen et al. describe the formation
of
heteroatom-substituted secondary phosphine oxides as decomposition products
and
preligands in rhodium-catalyzed hydroformylation. The corresponding secondary
organophosphites (C1) formed in the hydrolysis of tertiary phosphites
represent a
problematic impurity in the crude chelating diphosphite solution since they
act as acid and
decompose the acid-labile chelating diphosphites over the course of time. In
addition, the
compounds (C1) act as catalyst poison by complexing transition metals such as
rhodium
and when they accumulate in the reactor over prolonged periods of time can
lead to
deposition of the transition metal from the homogeneous reaction solutions and
lead to
rhodium losses. Since the transition metal is then no longer available for
catalysis,
operational malfunctions are the result. Especially in hydroformylation, the
compounds
(C1) can condense with the aldehydes formed to give a-hydroxyphosphonates
(02). Both
the compounds (C1) and the compounds (C2) lead, as a result of their acidity,
to hydrolytic
decomposition of the chelating phosphite ligands. This process also proceeds
autocatalytically since further (C1) is formed in the hydrolysis of the
chelating phosphite
ligands.
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Rxn Rxt,
0 0
XX
/ \H \Rz
0 0
OH
Fen Rxn
(01) (C2)
EP 0 285 136 A2 describes a method of purifying tertiary organophosphites by
separating
off secondary organophosphites, especially secondary organophosphites having a
tetracoordinated phosphorus atom as in C1. This document refers to the problem
that
secondary organophosphites generally cannot be separated off from tertiary
organophosphites by simple recrystallization since these compounds frequently
cocrystallize. EP 0 285 136 A2 therefore teaches adding water and a Lewis base
which
selectively converts secondary organophosphites into salts of primary
organophosphites to
a solution of the secondary and tertiary organophosphites in an organic
solvent so that the
salts of primary organophosphites can then be separated off from the tertiary
organophosphites. Suitable Lewis bases are NaOH and tertiary amines, e.g.
triethylamine.
CN 101684130A describes a process for preparing chelating phosphites, in which
a.) the phosphomonochloridite forming the side wings is dissolved in
dichloromethane,
b.) the aromatic diol which bridges the two phosphorus atoms is dissolved
in
triethylamine or a triethylamine/dichloromethane mixture,
c.) the solutions from a.) and b.) are mixed and reacted at from -40 C to
20 C,
d.) the resulting solution is stirred at from 20 to 30 C for from 10 to 20
hours and
e.) deionized water is added to the solution from step d.), the mixture
is stirred, the
phases are allowed to separate, with the lower organic phase comprising the
phosphite product.
The chelating phosphites obtained in this way are characterized, inter alia,
by a chloride
ion content of less than 0.01% by weight (100 ppm).
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US 2003/0100787 describes a process for preparing sterically hindered triaryl
monophosphites, but a possible use for preparing diphosphites is not
described. According
to the preparative examples, the synthesis of these monophosphites is carried
out by
reaction of substituted phenols with P0I3 in the presence of pyridine and
methylene
chloride as solvent. After the reaction, the methylene chloride is distilled
off and the
monophosphite is induced to crystallize by addition of isopropanol.
Studies on the rhodium-catalyzed hydroformylation of 1-octene and styrene
using bulky
chelating phosphite ligands are described in Organometallics 1996, 15(2), 835-
847. In the
preparation of ligand (9) (6,6'4[3,3',5,5'-tetrakis(1,1-dimethylethyl)-1,11-
biphenyl]-2,2'-
diylibis(oxy)]bisdibenzo[d,f] [1,3,2]clioxaphosphepin), it is stated that the
ligand obtained
after taking off the solvent and excess pyridine is firstly induced to
crystallize by addition of
acetonitrile and is then recrystallized from a toluene/acetonitrile mixture.
US 5,312,996 describes, in column 18, line 60 ff., a ligand synthesis by
reaction of
1,1'-biphenyl-3,3'-di-tert-butyl-5,5'-di-tert-butoxy-2,2'-diol with biphenol
chloridite in toluene
and in the presence of pyridine. The pyridinium chloride formed is filtered
off from the
reaction product obtained. The resulting solution is evaporated on a rotary
evaporator until
it has a syrupy consistency and the diphosphite obtained is then precipitated
by addition of
acetonitrile. The solid obtained is filtered off, washed with acetonitrile and
dried.
It is an object of the present invention to provide a simple and effective
method of purifying
organic diphosphite compounds. The diphosphite compound obtained should have a
purity
which makes it possible for the diphosphite compound to be used as ligand in a
continuous industrial process. Contamination with compounds from the
production
process, e.g. acetonitrile, which have an adverse effect on use of the organic
diphosphites
as ligands for catalysts for homogeneous catalysis should be avoided. In
particular, the
content of secondary organophosphites should also be very low. The organic
diphosphite
compound obtained should preferably be obtained in a solid form with good use
properties. Such forms include, for example, crystals which are large enough
for them to
be able to be separated off readily by filtration and/or have only a small
level of occlusions
of solvent (occluded solvent) with impurities comprised therein.
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It has now surprisingly been found that a crude organic diphosphite which is
at least partly
dissolved in an organic solvent can be effectively freed of the abovementioned
impurities
by precipitation by means of a precipitant (i.e. a solvent in which it is
sparingly soluble).
SUMMARY OF THE INVENTION
The invention firstly provides a method of purifying organic diphosphites of
the general
formula (I)
R6
R11
R2
R3
R10 R12 R5 R7
R9 =0 Ri 411 R4
/0 1401 Rs
O¨P
p¨O R9
R8 0/ R4 40 R 0
1401
R12= R10
R3 R2
R7 R11
R
6
(I)
where
R1, R2, R3 and R4 are each, independently of one another, hydrogen, CI-Cu-
alkyl, C1-C12-
1 5 alkoxy, C3-C12-cycloalkyl, C3-C12-heterocycloalkyl, C6-C20-aryl,
chlorine, bromine,
hydroxy, formyl, acyl or alkoxycarbonyl,
where two adjacent radicals R1 to R4 together with the carbon atoms of the
benzene
ring to which they are bound can also form a fused ring system with a further
benzene ring,
R5, Rs, R7, Rs, R9, R10, R11 and R12 are each, independently of one another,
hydrogen, Ci-
Ci-C12-alkoxy, C3-C12-cycloalkyl, C3-Cu-heterocycloalkyl, C6-C20-aryl,
chlorine, formyl, acyl or alkoxycarbonyl,
CA 02862041 2015-11-27
where two adjacent radicals R5 to R12 together with the carbon atoms of the
benzene
ring to which they are bound can also form a fused ring system with a further
benzene ring,
5 where Ci-C12-alkyl and Ci-C12-alkoxy can each be unsubstituted or
substituted by
one or more identical or different radicals Ra selected from among C3-C12-
cycloalkyl,
C3-Cu-heterocycloalkyl, C6-C20-aryl, fluorine, chlorine, cyano, formyl, acyl
and
alkoxycarbonyl,
10 where C3-Cu-cycloalkyl and C3-Cu-heterocycloalkyl can each be
unsubstituted or
substituted by one or more identical or different radicals Rb selected from
among Ci-
C12-alkyl, Ci-C12-alkoxy, C3-Cu-cycloalkyl, C3-Ci2-heterocycloalkyl, Cs-Cm-
aryl,
fluorine, chlorine, bromine, cyano, formyl, acyl and alkoxycarbonyl,
where C6-C20-aryl and can in each case be unsubstituted or substituted by one
or
more identical or different radicals Rc selected from among CI-Cu-alkyl, CI-Cu-
alkoxy, C3-Cu-cycloalkyl, C3-Cu-heterocycloalkyl, C6-C20-aryl, fluorine,
chlorine,
bromine, cyano, formyl, acyl and alkoxycarbonyl,
wherein a crude organic diphosphite of the general formula (l) which is at
least partly
dissolved in a first solvent (L1) selected from among alkylbenzenes, aryl
alkyl ethers,
chlorobenzene and mixtures thereof is precipitated by admixing with a second
solvent (L2)
selected from among linear Ci-C4-alkanols, ethylene glycol di(Ci-C4-alkyl)
ethers and
mixtures thereof.
Preference is given to a method of purifying organic diphosphites of the
general formula (l)
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11
R6
Ril
R2 R3
7
R R7
R10 R12
R9 el 0 Ri 11 R4 0 s
R8
7 0 R5
O-P
p-O \ R
R8 0/ R4 4i R3 R2 R1
R12 0 R10
R
R6
(l)
where
R1, R2, R3 and R4 are each, independently of one another, hydrogen,
unsubstituted
straight-chain or branched Ci-C6-alkyl, unsubstituted straight-chain or
branched Cl-
C6-alkoxy, C6-Cio-aryl, chlorine, formyl, acyl or (Ci-C6-alkoxy)carbonyl,
where two adjacent radicals R1 to R4 together with the carbon atoms of the
benzene
ring to which they are bound can also form a fused ring system with a further
benzene ring,
R5, Rs, R7, R8, R9, R10, R11 and R12 are each, independently of one another,
hydrogen,
unsubstituted straight-chain or branched Ci-C6-alkyl, unsubstituted straight-
chain or
branched Ci-C6-alkoxy, C6-Cio-aryl, chlorine, formyl, acyl or (Ci-C6-
alkoxy)carbonyl,
where two adjacent radicals R5 to R12 together with the carbon atoms of the
benzene
ring to which they are bound can also form a fused ring system with a further
benzene ring,
wherein a crude organic diphosphite of the general formula (l) which is at
least partly
dissolved in a first solvent (L1) selected from among alkylbenzenes, aryl
alkyl ethers,
chlorobenzene and mixtures thereof is precipitated by admixing with a second
solvent (L2)
selected from among linear Ci-C4-alkanols, ethylene glycol di(Ci-C4-alkyl)
ethers and
mixtures thereof.
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12
In a first variant of the method, precipitation of the crude organic
diphosphite is preferably
effected by crystallization.
A first variant is a method in which
a) a solution comprising the crude organic diphosphite of the general
formula (I) and
the first solvent (L1) is provided,
b1) the organic diphosphite is partly crystallized out by distilling off
part of the first
solvent (L1) and, to complete the crystallization, the second solvent (L2) is
added
and
c) the crystallized organic disphosphite is separated off from the
liquid phase.
The organic diphosphite is preferably partly crystallized out hot in step b1)
by distilling off
part of the first solvent (L1).
A second variant is a method in which
a) a solution comprising the crude organic diphosphite of the general
formula (I) and
the first solvent (L1) is provided,
b2) the solution provided in step a) is added to the second solvent (L2),
with the organic
diphosphite at least partly precipitating, and
c) the precipitated organic diphosphite is separated off from the liquid
phase.
In a preferred embodiment, the solution provided in step a) is added hot to
the second
solvent (L2) in step b2).
In a preferred embodiment, the organic diphosphite obtained in step c) is
worked up by
subjecting it to washing with a liquid washing medium (step d)).
CA 02862041 2015-11-27
'13
The invention further provides for the use of a transition metal catalyst
comprising, as a
ligand, at least one organic diphosphite obtained by a purification method as
defined
above and below for hydroformylation, hydrocyanation or hydrogenation.
DESCRIPTION OF THE INVENTION
The method of the invention has the following advantages:
- The method is simple and effective.
- The organic diphosphites obtained are sufficiently pure for them to be
used as ligand
in a continuous industrial process without adverse effects.
- The purification method of the invention makes it possible, in
particular, to achieve a
significant reduction in the content of secondary organophosphites.
- The diphosphite compounds obtained have no detectable amounts of diols of
the
general formula (Aii)
R2 R3
R1 R4
(Aii)
OH
HO
R4 Ri
R3 R2
which form the backbone of the organic diphosphites of the general formula
(I). The
diols (Aii) are undesirable because of their relatively high acidity and the
subsequent
associated risk of destruction of the organic diphosphites.
The diphosphite compounds obtained have only low contents of halide ions,
especially chloride ions.
- The diphosphite compounds obtained have, in particular, no detectable
amounts of
secondary phosphites C1 or tertiary monophosphites D1 and/or D2
CA 02862041 2015-11-27
14
FR"
R1 0 0 R1 R12 0 0 R5
R2 4. 414 R2 R11
R6
R4 R4 R9 R10
R9 R8 R7
(01) (D2)
where R' is alkoxy, preferably Ci-C4-alkoxy, in particular methoxy. This is
surprisingly
also the case when a Ci-C4-alkanol, in particular methanol, is used as second
solvent (L2).
The second variant of the method of the invention (comprising steps a), b2)
and c)) is
particularly preferred. It additionally has the following advantages:
The organic diphosphite is obtained in the form of fine, very readily
filterable crystals.
- The organic diphosphite occludes only small amounts of the mother liqor,
i.e.
solvents L1, L2 and impurities dissolved therein. Merely to avoid
misunderstandings,
it is pointed out that occlusions of solvent are not solvates in which the
solvent is
incorporated into the crystal lattice and which form a different crystal than
the
corresponding nonsolvates.
- Further purification by recrystallization is not necessary.
The product obtained by the method of the invention is a free-flowing powder
which
does not tend to cake during storage and retains its free-flowing nature over
a
prolonged period of time.
For the purposes of the invention, a crude diphosphite is a composition of the
organic
diphosphite of the general formula (I) before purification, as is generally
formed in the
synthesis thereof and comprises one or more impurities, e.g. by-products,
starting
materials, catalysts and/or other auxiliaries for the synthesis.
When the organic diphosphites (I) are used as ligands in homogeneous
catalysis, such
impurities can have an adverse effect on the activity, selectivity and/or
stability of the
catalyst and/or cause other problems in use, e.g. corrosion problems, or
contamination of
the product of the catalyzed reaction, e.g. in the form of discoloration.
CA 02862041 2015-11-27
For the purposes of the invention, the admixing of the organic diphosphite of
the general
formula (I) dissolved in the first solvent (L1) with a second solvent (L2) is
quite generally
not limited to a particular order of addition. In principle, the solution of
the organic
5 diphosphite (I) in (L1) can be added to (L2) or (L2) can be added to the
solution of the
organic diphosphite (I) in (L1) or the two liquid media can be combined in
another suitable
way.
However, in the above-described second variant of the method of the invention,
a solution
10 comprising the crude organic diphosphite of the general formula (I) and
the first solvent
(L1) is added to the second solvent (L2).
The addition of the crude organic diphosphite dissolved in the first solvent
(L1) to the
second solvent (L2) gives a solid phase enriched in the organic diphosphite
and at least
15 one liquid phase enriched in the impurities of the crude organic
diphosphite. Solid-liquid
phase separation gives a purified diphosphite comprising a lower level of
impurities
compared to the crude diphosphite.
The impurities can be, for example:
- basic compounds, especially the bases used for scavenging hydrogen halide
in the
process for preparing the organic diphosphite (generally an organic nitrogen-
comprising compound, e.g. an amine),
- acid salts of the basic compounds,
- hydrogen halides and/or salts thereof,
monoxides of the organic diphosphite,
- dioxides of the organic diphosphite,
- secondary organophosphites as are formed, for example, in the hydrolysis
of the
phosphochloridite used for introduction of the side wings,
- starting materials and intermediates other than the impurities mentioned
above from
the process for preparing the organic diphosphite,
CA 02862041 2015-11-27
16
components other than the impurities mentioned above, e.g. catalysts and
additives
used in the preparation of the organic diphosphite and/or by-products formed
therefrom, etc.,
mixtures of at least two of the abovementioned impurities.
The purified organic diphosphite obtained by the method of the invention
preferably has a
purity of at least 95%, particularly preferably at least 98%, in particular at
least 99.5%.
The purity is for the present purposes the "chemical purity" and refers to the
molar
proportion of the organic diphosphite obtained by the method of the invention
and also the
solvates of the organic diphosphite obtained by the method of the invention
based on the
total solid mixture obtained in the purification. That is to say, solid
organic diphosphites
which comprise solvent incorporated into the crystal lattice (known as solvate
crystals)
obtained by the method of the invention are counted as part of the pure
compounds.
The organic diphosphite obtained by the method of the invention generally
comprises
secondary organophosphites in an amount of not more than 1% by weight,
particularly
preferably not more than 0.5% by weight, in particular not more than 0.2% by
weight,
based on the total weight of the pure organic diphosphite obtained by the
method of the
invention, including solvates thereof.
The organic diphosphite obtained by the method of the invention generally
comprises
nitrogen-comprising compounds in an amount of not more than 20 ppm,
particularly
preferably not more than 10 ppm, based on the total weight of the pure organic
diphosphite, including solvates thereof.
The organic diphosphite obtained by the method of the invention generally
comprises
halides (especially chloride) in an amount of not more than 20 ppm,
particularly preferably
not more than 10 ppm, based on the total weight of the pure organic
diphosphite obtained
by the method of the invention, including solvates thereof.
The organic diphosphite obtained by the method of the invention does not
comprise any
amounts which can be detected by 31P-NMR of phosphites D1 and/or D2
CA 02862041 2015-11-27
17
R" R"
R1 0 0 R1 R12 0 0 R5
R2 441 R2 R 1 1 110
R6
R3 R4 R4 R3 R19 R9 R8 R7
(D1) (D2)
where R' is alkoxy, preferably Ci-C4-alkoxy, in particular methoxy.
In general, the organic diphosphites purified by the method of the invention
can be used
without further work-up or purification, e.g. by recrystallization, as ligands
in homogenous
catalysis.
The first solvent (L1) preferably has a boiling point at 1013 mbar of at least
100 C,
particularly preferably at least 110 C.
As first solvent (L1), preference is given to using a solvent or solvent
mixture selected from
among (Ci-C4-alkyl)benzenes, Ci-C4-alkyl phenyl ethers, chlorobenzene and
mixtures
thereof.
(Ci-C4-alkyl)benzenes suitable as solvent (L1) are, for example, toluene,
ethylbenzene, o-,
m- or p-xylene, cumene (isopropylbenzene) and mixtures thereof.
(Ci-C4-alkyl) phenyl ethers suitable as solvent (L1) are, for example, anisole
(methyl
phenyl ether), ethoxybenzene (phenetole),propoxybenzene, isopropoxybenzene and
mixtures thereof.
The first solvent (L1) is particularly preferably selected from among toluene,
ethylbenzene,
o-, m- or p-xylene, cumene, anisole, chlorobenzene and mixtures thereof.
In particular, toluene is used as first solvent (L1).
CA 02862041 2015-11-27
18
As second solvent (L2), use is made according to the invention of a solvent or
solvent
mixture selected from among linear C1-C4-alkanols, ethylene glycol di(Ci-C4-
alkyl) ethers
and mixtures thereof.
The second solvent (L2) is particularly preferably selected from among
methanol, ethanol,
ethylene glycol dimethyl ether and mixtures thereof.
Surprisingly, no appreciable alcoholysis of the organic diphosphites (I) is
observed even
when using linear Cl-C4-alkanols as second solvent (L2).
In particular, methanol is used as second solvent (L2).
The first solvent (L1) and the second solvent (L2) are preferably completely
miscible with
one another. If a first solvent (L1) and a second solvent (L2) which are not
completely
miscible with one another are used, they are preferably used in a ratio which
is not in a
miscibility gap.
Use of a sufficient amount of the second solvent (L2) makes it possible for
the organic
diphosphite which is at least partly dissolved in the solvent (L1) to be
precipitated
essentially completely. The abovementioned solvents (L1) and (L2) result in a
liquid
mother liqor which comprises the major part of the impurities in dissolved
form.
The addition of the solution of the crude organic diphosphite (I) in the first
solvent (L1) to
the second solvent (L2) can be carried out in a single addition step or in
portions. If
desired, the addition can also be carried out in the form of a fractional
crystallization, with
the fractions obtained each being able to be isolated before the further
addition of (L2).
The weight ratio of first solvent (L1) to second solvent (L2) is
advantageously selected so
that the organic diphosphite (I) to be purified is precipitated virtually
completely after
complete addition of the second solvent (L2).
The weight ratio of L1 to L2 is preferably in the range from 1:99 to 95:5,
particularly
preferably from 2:98 to 90:10, in particular from 5:95 to 80:20.
CA 02862041 2015-11-27
19
In a particularly preferred embodiment, toluene is used as solvent (L1) and
methanol is
used as solvent (L2). The weight ratio of L1 to L2 is then preferably in the
range from 1:99
to 75:25, particularly preferably from 1:99 to 50:50. A particularly preferred
weight ratio of
toluene (L1) to methanol (L2) is in the range from 35:65 to 45:55.
The precipitated organic diphosphite is preferably separated off from the
liquid phase and
the organic diphosphite which has been separated off is subjected to washing
with a liquid
washing medium. The organic disphosphite can be subjected to a treatment with
a
washing medium either once or a plurality of times in succession. Suitable
washing media
are those in which the organic diphosphites (I) do not dissolve or dissolve
only in small
amounts and which readily dissolve the impurities in the diphosphites.
Preferred washing
media are the above-described second solvents (L2). The second solvent (L2)
which is
also used for the precipitation is preferably used as washing medium. A
particularly
preferred washing medium is methanol. In a particularly preferred embodiment,
the
organic diphosphite is firstly subjected to single or multiple washing with
methanol and
subsequently thereto washing with acetone to displace the methanol.
It has surprisingly been found that addition of a base to the washing medium
has an
advantageous effect on the stability of the organic diphosphite purified by
the method of
the invention. In the case of a plurality of washing steps, the base can be
added in one or
more of the washing steps. This applies, for example, to the washing medium
used in the
last washing step in the case of a plurality of washing steps. The base is
particularly
preferably added in all washing steps using methanol. In a preferred
embodiment, the
organic diphosphite which has been separated off from the liquid phase is
therefore firstly
subjected to single or multiple washing with basic methanol and to final
washing with
acetone to displace the methanol and to displace residues of base.
The base is advantageously dissolved in the washing medium. Suitable bases
are, for
example, alkali metal hydroxides, e.g. NaOH and KOH, and alkali metal
alkoxides, e.g.
sodium methoxide, potassium methoxide, sodium tert-butoxide, potassium tert-
butoxide,
sodium tert-pentoxide and potassium tert-pentoxide, etc.
CA 02862041 2015-11-27
Preference is given to using an alkali metal alkoxide, in particular sodium
methoxide, as
base.
In a particularly preferred embodiment, methanol to which sodium methoxide has
been
5 added as base is used as washing medium.
A base is preferably added to the washing medium in an amount of from 0.01 to
10% by
weight, particularly preferably from 0.05 to 5% by weight, based on the total
weight of the
washing medium.
The use of a base as additive to the washing medium significantly reduces the
risk of no
longer controllable decomposition of the organic diphosphite on heating, e.g.
on drying at
temperatures above 150 C.
As regards the configuration of washing with the washing medium, the
information given
below under step d) is fully incorporated by reference.
The organic diphosphite used for purification is preferably selected from
among
diphosphite compounds as are described, for example, in EP 0 214 622 A2, US
4,668,651,
US 4,769,498, US 5,663,403, US 5,728,861 and US 6,172,267.
The method of the invention is also suitable for purifying organic
diphosphites in which one
of the phosphorus atoms or both phosphorus atoms are not part of a
heterocycle. Such
organic diphosphites can, for example, be obtained by reaction of PCI3 with
two molar
equivalents or four molar equivalents of the appropriate monoalcohols (instead
of one
molar equivalent or two molar equivalents of the diols forming the side wings)
and
subsequent reaction with the diol forming the bridging group between the
phosphorus
atoms. Such diphosphite compounds and their preparation are described, for
example, in
US 4,748,261, US 4,885,401, US 5,235,113 and US 5,391,801.
In a particularly preferred embodiment, possible compounds are the compounds
mentioned in US 4,668,651, in particular the compounds described in column 9,
line 25 to
column 16, line 53 and examples 1 to 11 and also ligands A to Q.
CA 02862041 2015-11-27
21
In a particularly preferred embodiment, possible compounds are the compounds
mentioned in US 4,748,261, in particular the compounds described in column 14,
line 26 to
column 62, line 48 and examples 1 to 14 and also ligands 1 to 8.
In a particularly preferred embodiment, possible compounds are the compounds
mentioned in US 4,769,498, in particular the compounds described in column 9,
line 27 to
column 18, line 14 and examples 1 to 14 and also ligands A to Q.
In a particularly preferred embodiment, possible compounds are the compounds
mentioned in US 4,885,401, in particular the compounds described in column 12,
line 43 to
column 30 and examples 1 to 14 and also ligands 1 to 8.
In a particularly preferred embodiment, possible compounds are the compounds
mentioned in US 5,235,113, in particular the compounds described in column 7
to column
40, line 11 and examples 1 to 22.
In a particularly preferred embodiment, possible compounds are the compounds
mentioned in US 5,391,801, in particular the compounds described in column 7
to column
40, line 38 and examples 1 to 22.
In a particularly preferred embodiment, possible compounds are the compounds
mentioned in US 5,663,403, in particular the compounds described in column 5,
line 23 to
column 26, line 33 and examples 1 to 13.
In a particularly preferred embodiment, possible compounds are the compounds
mentioned in US 5,728,861, in particular the compounds described in column 5,
line 23 to
column 26, line 23 and examples 1 to 13 and also ligands 1 to 11.
In a particularly preferred embodiment, possible compounds are the compounds
mentioned in US 6,172,267, in particular the compounds described in column 11
to column
40, line 48 and examples 1 and 2 and also ligands 1 to 11.
CA 02862041 2015-11-27
22
According to the invention, the organic diphosphite is selected from compounds
of the
general formula (I)
R6
R" R2 R3
R5 R7
lel
R" R12
9
0 R1 ii R4 el 8
0 R
R O¨P
p¨O
R' R R9
R87 le .5 R4 R3 R2 it R1\õ 40
D12 io
R
1`
R11
R6
(1)
where R1 to R12 have the meanings indicated above and in the following.
For the purposes of the invention, halogen is fluorine, chlorine, bromine or
iodine,
preferably fluorine, chlorine or bromine.
In the following, the expression "C1-C12-alkyl" comprises straight-chain and
branched Ci-
C12-alkyl groups. Preference is given to unsubstituted straight-chain or
branched Cl-C8-
alkyl groups and very particularly preferably Ci-C6-alkyl groups. Examples of
Ci-C12-alkyl
groups are, in particular, methyl, ethyl, propyl, isopropyl, n-butyl,
isobutyl, sec-butyl, tert-
butyl (1,1-dimethylethyl), n-pentyl, 2-pentyl, 2-methylbutyl, 3-methylbutyl,
1,2-
dimethylpropyl, 1,1-dimethylpropyl, 2,2-dimethylpropyl, 1-ethylpropyl, n-
hexyl, 2-hexyl, 2-
methylpentyl, 3-methylpentyl, 4-methylpentyl, 1,2-dimethylbutyl, 1,3-
dimethylbutyl, 2,3-
dimethylbutyl, 1,1-dimethylbutyl, 2,2-dimethylbutyl, 3,3-dimethylbutyl, 1,1,2-
trimethylpropyl,
1,2,2-trimethylpropyl, 1-ethylbutyl, 2-ethylbutyl, 1-ethy1-2-methylpropyl, n-
heptyl, 2-heptyl,
3-heptyl, 2-ethylpentyl, 1-propylbutyl, n-octyl, 2-ethylhexyl, 2-propylheptyl,
nonyl, decyl.
The above explanations in respect of the expression "Ci-C12-alkyl" also apply
to the alkyl
groups in Ci-C12-alkoxy. Preference is given to unsubstituted straight-chain
or branched
Ci-C6-alkoxy groups.
Substituted Ci-C12-alkyl groups and substituted Ci-C12-alkoxy groups can,
depending on
their chain length, have one or more (e.g. 1, 2, 3, 4 or 5) substituents Ra.
The substituents
CA 02862041 2015-11-27
23
Ra are preferably selected independently from C3-C12-cycloalkyl, C3-Cu-
heterocycloalkyl,
C6-C20-aryl, fluorine, chlorine, bromine, cyano, formyl, acyl and
alkoxycarbonyl.
For the purposes of the present invention, the expression "alkylene" refers to
straight-chain
or branched alkanediyl groups which preferably have 1 to 6 carbon atoms. These
include
methylene (-CH2-), ethylene (-CH2-CH2-), n-propylene (-CH2-CH2-CH2-),
isopropylene (-
CH2-CH(CH3)-), etc.
For the purposes of the present invention, the expression "C3-Cu-cycloalkyl"
comprises
monocyclic, bicyclic or tricyclic hydrocarbon radicals having from 3 to 12, in
particular from
5 to 12, carbon atoms. They include cyclopropyl, cyclobutyl, cyclopentyl,
cyclohexyl,
cycloheptyl, cyclooctyl, cyclododecyl, cyclopentadecyl, norbornyl or
adamantyl.
For the purposes of the present invention, the expression "C3-C12-
heterocycloalkyl"
comprises nonaromatic, saturated or partially unsaturated cycloaliphatic
groups having
from 3 to 12, in particular form 5 to 12, carbon atoms. C3-Cu-heterocycloalkyl
groups
preferably have from 4 to 8, particularly preferably 5 or 6, ring atoms. In
contrast to
cycloalkyl groups, 1, 2, 3 or 4 of the ring carbons in heterocycloalkyl groups
are replaced
by heteroatoms or heteroatom-comprising groups. The heteroatoms or heteroatom-
comprising groups are preferably selected from among -0-, -S-,--C(=0)- and -
S(=0)2-.
Examples of C3-C12-heterocycloalkyl groups are tetrahydrothiophenyl,
tetrahydrofuranyl,
tetrahydropyranyl and dioxanyl.
Substituted C3-C12-cycloalkyl groups and substituted C3-C12-heterocycloalkyl
groups can,
depending on their ring size, have one or more (e.g. 1, 2, 3, 4 or 5)
substituents Rb. The
substituents Rb are preferably selected independently from among CI-Cu-alkyl,
CI-Cu-
alkoxy, C3-Ci2-cycloalkyl, C3-Cu-heterocycloalkyl, Cs-On-aryl, fluorine,
chlorine, bromine,
cyano, formyl, acyl and alkoxycarbonyl. Substituted C3-Cu-cycloalkyl groups
preferably
bear one or more, e.g. 1, 2, 3, 4 or 5, Ci-Cs-alkyl groups. Substituted C3-C12-
heterocycloalkyl groups preferably bear one or more, e.g. 1, 2, 3, 4 or 5, Ci-
C6-alkyl
groups.
CA 02862041 2015-11-27
24
Examples of substituted C3-Ci2-cycloalkyl groups are 2- and 3-
methylcyclopentyl, 2- and 3-
ethylcyclopentyl, 2-, 3- and 4-methylcyclohexyl, 2-, 3- and 4-ethylcyclohexyl,
2-, 3- and 4-
propylcyclohexyl, 2-, 3- and 4-isopropylcyclohexyl, 2-, 3- and 4-
butylcyclohexyl, 2-, 3- and
4-sec-butylcyclohexyl, 2-, 3- and 4-tert-butylcyclohexyl, 2-, 3- and 4-
methylcycloheptyl, 2-,
3- and 4-ethylcycloheptyl, 2-, 3- and 4-propylcycloheptyl, 2-, 3- and 4-
isopropylcycloheptyl,
2-, 3- and 4-butylcycloheptyl, 2-, 3- and 4-sec-butylcycloheptyl, 2-, 3- and 4-
tert-
butylcycloheptyl, 2-, 3-, 4- and 5-methylcyclooctyl, 2-, 3-, 4- and 5-
ethylcyclooctyl, 2-, 3-, 4-
and 5-propylcyclooctyl.
For the purposes of the present invention, the expression "C6-C20-aryl"
comprises
monocyclic or polycyclic aromatic hydrocarbon radicals. These have from 6 to
20 ring
atoms, particularly preferably from 6 to 14 ring atoms, in particular from 6
to 10 ring atoms.
Aryl is preferably C6-Clo-aryl. Aryl is particularly preferably phenyl,
naphthyl, indenyl,
fluorenyl, anthracenyl, phenanthrenyl, naphthacenyl, chrysenyl, pyrenyl,
coronenyl,
perylenyl, etc. In particular, aryl is phenyl or naphthyl.
Substituted C6-C20-aryl groups can, depending on their ring size, have one or
more (e.g. 1,
2, 3, 4 or 5) substituents Rc. The substituents IRc are preferably selected
independently
from among Ci-C12-alkyl, Ci-C12-alkoxy, C3-Ci2-cycloalkyl, C3-C12-
heterocycloalkyl, C6-C20-
aryl, fluorine, chlorine, bromine, cyano, formyl, acyl and alkoxycarbonyl.
Substituted C6-C20-aryl is preferably substituted C6-C10-aryl, in particular
substituted phenyl
or substituted naphthyl. Substituted C6-C20-aryl groups preferably bear one or
more, e.g. 1,
2, 3, 4 or 5 substituents selected from among Cl-C6-alkyl groups, Cl-C6-alkoxy
groups,
chlorine and bromine.
For the purposes of the present invention, the term "acyl" refers to alkanoyl-
or aroyl
groups which generally have from 2 to 11, preferably from 2 to 8, carbon
atoms. They
include, for example, acetyl, propanoyl, butanoyl, pentanoyl, hexanoyl,
heptanoyl-,
2-ethylhexanoyl, 2-propylheptanoyl, pivaloyl, benzoyl or naphthoyl.
For the purposes of the present invention, carboxylate is preferably a
derivative of a
carboxylic acid function, in particular a carboxylic ester function or a
carboxamide function.
CA 02862041 2015-11-27
Such functions include, for example, the esters with Cl-C4-alkanols such as
methanol,
ethanol, n-propanol, isopropanol, n-butanol, sec-butanol and tert-butanol.
Also included
are the primary amides and N-alkyl and N,N-dialkyl derivatives thereof.
5 Fused ring systems can be aromatic, hydroaromatic and cyclic compounds
joined by
fusion (fused-on). Fused ring systems comprise two, three or more than three
rings.
Depending on the type of linkage, a distinction is made among fused ring
systems
between ortho-fusion, i.e. each ring shares an edge or two atoms with each
adjacent ring,
and peri-fusion in which one carbon atom belongs to more than two rings. Among
the
10 fused ring systems, preference is given to ortho-fused ring systems.
In the organic diphosphites of the general formula (I), preference is given to
the radicals R1
and R3 each being, independently of one another, Ci-C4-alkyl or Ci-C4-alkoxy
and R2 and
R4 each being hydrogen. Greater preference is given to the radicals R1 and R3
being
15 selected independently from among methyl, ethyl, isopropyl, tert-butyl
and methoxy and R2
and R4 each being hydrogen.
In the organic diphosphites of the general formula (I), preference is given to
the radicals
R1, R3 and R4 each being, independently of one another, Ci-C4-alkyl or Ci-C4-
alkoxy and
20 the radicals R2 each being hydrogen. Greater preference is given to R1,
R3 and R4 being
selected independently from among methyl, ethyl and methoxy and R2 being
hydrogen.
In the organic diphosphites of the general formula (I), preference is given to
the radicals R4
each being, independently of one another, Cl-C4-alkyl or Cl-C4-alkoxy and R1,
R2 and R3
25 each being hydrogen. Greater preference is given to the radicals R4
being selected
independently from among methyl, ethyl, isopropyl, tert-butyl and methoxy and
R1, R2 and
R3 each being hydrogen.
In the organic diphosphites of the general formula (I), preference is given to
the radicals R1
each being, independently of one another, Ci-C4-alkyl or Ci-C4-alkoxy and R2,
R3 and R4
each being hydrogen. Greater preference is given to the radicals R1 being
selected
independently from among methyl, ethyl, isopropyl, tert-butyl and methoxy and
R2, R3 and
R4 each being hydrogen.
CA 02862041 2015-11-27
26
In the organic diphosphites of the general formula (I), preference is given to
the radicals R3
and R4 together forming a fused benzene ring and R1 and R2 each being
hydrogen, i.e. the
group of the formula
R2 R3
R1 411 R4
R4 op R1
R3
R2
is
1104 411
ID =
In the organic diphosphites of the general formula (I), the two groups
R12
R5
R11 it
R6
R10
R9 R8 R7
can have identical or different meanings. In a preferred embodiment, both
groups have the
same meaning.
In the organic diphosphites of the general formula (I), preference is given to
the radicals R5
and R12 each being, independently of one another, Ci-C4-alkyl or Cl-C4-alkoxy
and R6, R7,
R8, R9, R19 and R11 each being hydrogen. Greater preference is given to R5 and
R12 being
selected independently from among methyl, ethyl, isopropyl, tert-butyl and
methoxy and
R6, R7, R8, R9, R19 and R11 each being hydrogen.
CA 02862041 2015-11-27
27
In the organic diphosphites of the general formula (I), preference is given to
the radicals
R5, R7, R10 and R12 each being, independently of one another, Cl-C4-alkyl or
Cl-C4-alkoxy
and R6, R8, R9 and R11 each being hydrogen. Greater preference is given to R5,
R7, Rlo
and R12 being selected independently from among methyl, ethyl, isopropyl, tert-
butyl and
methoxy and R6, R8, R9 and R11 each being hydrogen.
In the organic diphosphites of the general formula (I), preference is given to
the radicals
R5, R7, R8, R9, R10 and R12 each being, independently of one another, Ci-C4-
alkyl or C1-C4-
alkoxy and R6 and R11 each being hydrogen. Greater preference is given to R5,
R7, R8, R9,
R19 and R12 being selected independently from among methyl, ethyl, isopropyl,
tert-butyl
and methoxy and R6 and R11 each being hydrogen.
In the organic diphosphites of the general formula (I), preference is given to
the radicals R8
and R9 each being, independently of one another, Cl-C4-alkyl or Ci-C4-alkoxy
and R5, R6,
R7, R1o, R11 and R12 each being hydrogen. Greater preference is given to R8
and R9 being
selected independently from among methyl, ethyl, isopropyl, tert-butyl and
methoxy and
R5, Rs, R7, R10, R11 and R12 each being hydrogen.
In the organic diphosphites of the general formula (I), the radicals R5, Rs,
R7, Rs, R9, R10,
R11 and R12 are each preferably hydrogen.
In the compounds of the general formula (I), the group
R2 R3
R1 11 R4
R4 it R1
R3 R2
CA 02862041 2015-11-27
28
is preferably selected from among 3,3',5,5'-tetramethy1-1,1'-bipheny1-2,2'-
diyl, 3,31,5,5'-
tetraethy1-1,11-bipheny1-2,2'-diyl, 3,3',5,5'-tetra-n-propy1-1,11-bipheny1-
2,2'-diyl, 3,3'-
dimethy1-5,5'-dichloro-1,1'-bipheny1-2,2"-diyl, 3,3'-diethy1-5,5'-dibromo-1,1'-
bipheny1-2,2'-
diyl, 3,3'-dimethy1-5,5'-diethyl-1,1'-biphenyl-2,2'-diyl, 3,3'-dimethy1-5,5'-
di-n-propy1-1,1'-
biphenyl-2,2'-diyl, 3,3',5,5'-tetraisopropy1-1,1'-bipheny1-2,2'-diyl,
3,3',5,5'-tetra-n-buty1-1,t-
bipheny1-2,2'-diyl, 3,3',5,5'-tetraisobuty1-1,11-bipheny1-2,2'-diyl, 3,3',5,5'-
tetra-sec-buty1-1,1'-
bipheny1-2,2'-diyl, 3,3',5,5'-tetra(1,1-dimethylethyl)-1,11-bipheny1-2,2'-
diyl, 3,3'-di(1,1-
dimethylethyl)-5,5'-di-n-amy1-1,11-bipheny1-2,2'-diyl, 3,3',5,5'-tetrakis(1,1-
dimethylpropy1)-
1,1'-bipheny1-2,2'-diyl, 3,3'-di(1,1-dimethylethyl)-5,5'-bis(1,1-
dimethylpropy1)-1,11-biphenyl-
2,2'-diyl, 3,3'-di(1,1-dimethylethyl)-5,5'-di-n-hexy1-1,11-biphenyl-2,2'-diy1,
3,3'-di(1,1-
dimethylethyl)-5,5'-di-2-hexy1-1,11-biphenyl-2,2'-diy1, 3,3'-di(1,1-
dimethylethyl)-5,5'-di-3-
hexy1-1,1'-biphenyl-2,2'-diyl, 3,3'-di(1,1-dimethylethyl)-5,5'-di-n-hepty1-1,1-
biphenyl-2,2'-
diyl, 3,3'-di(1,1-dimethylethyl)-5,5'-di-2-hepty1-1,1'-biphenyl-2,2'-diyl,
3,3'-di(1,1-
dimethylethyl)-5,5'-di-3-hepty1-1,1'-bipheny1-2,2'-diyl, 3,3'-di(1,1-
dimethylethyl)-5,5'-di-4-
hepty1-1,1'-bipheny1-2,2'-diyl, 3,3'-di(1,1-dimethylethyl)-5,5'-di-n-octy1-
1,11-biphenyl-2,2'-diyl,
3,3'-di(1,1-dimethylethyl)-5,5'-di-2-octy1-1,1'-biphenyl-2,2'-diyl, 5,5'-di-3-
octy1-1,1'-biphenyl-
2,2'-diyl, 3,3'-di(1,1-dimethylethyl)-5,5'-di-4-octy1-1,11-biphenyl-2,2'-diyl,
3,3'-di(1,1-
dimethylethyl)-5,5'-bis(1,1,3,3-tetramethylbuty1)-1,11-biphenyl-2,2'-diyl,
3,3',5,5'-
tetrakis(1,1,3,3-tetramethylbuty1)-1,1'-bipheny1-2,2'-diyl, 3,3'-di(1,1-
dimethylethyl)-5,5',6,6'-
tetramethy1-1,11-bipheny1-2,2'-diyl, 3,3'-di(1,1-dimethylethyl)-5,5'-dipheny1-
1,11-biphenyl-
2,2'-diyl, 3,3'-di(1,1-dimethylethyl)-5,5'-bis(2,4,6,-trimethylpheny1)-1,1'-
biphenyl-2,2'-diyl,
3,3'-di(1,1-dimethylethyl)-5,5'-dimethoxy-1,1'-bipheny1-2,2'-diyl, 3,3'-di(1,1-
dimethylethyl)-
5,5'-diethoxy-1,11-bipheny1-2,2'-diyl, 3,3'-di(1,1-dimethylethyl)-5,5'-di-n-
propoxy-1,1 '-
bipheny1-2,2'-diyl, 3,3'-di(1,1-dimethylethyl)-5,5'-diisopropoxy-1,1'-bipheny1-
2,2'-diyl, 3,3'-
di(1,1-dimethylethyl)-5,5'-di-n-butoxy-1,11-bipheny1-2,2'-diyl, 3,3'-di(1,1-
dimethylethyl)-5,5'-
di-sec-butoxy-1,1'-bipheny1-2,2'-diyl, 3,3'-di(1,1-dimethylethyl)-5,5'-
diisobutoxy-1,1 '-
bipheny1-2,2'-diyl, 3,3'-di(1,1-dimethylethyl)-5,5'-di-tert-butoxy-1,1'-
bipheny1-2,2'-diyland
1,1'-binaphthaleny1-2,2'-diyl.
The group
CA 02862041 2015-11-27
29
R2 R3
4
R1 .R4
R 65"4110-3' R1
4'
R2
is particularly preferably 3,3',5,5'-tetra(1,1-dimethylethyl)-1,1'-bipheny1-
2,2'-diyl, i.e.
particular preference is given to the radicals R1 and R3 in the organic
diphosphites of the
5 general formula (1) each being tert-butyl and R2 and R4 each being
hydrogen.
In the compounds of the general formula (1), the groups
R12
R5
R6
R11 R
R10 9 R8 R7
are preferably selected independently from among 1,1'-bipheny1-2,2'-diyl, 5,5'-
dimethyl-
1,1'-bipheny1-2,2'-diyl, 5,5'-dichloro-1,11-bipheny1-2,2'-diyl, 5,5'-dibromo-
1,1'-bipheny1-2,2'-
diyl, 5,5'-diethyl-1,11-bipheny1-2,2'-diyl, 5,5'-di-n-propy1-1,1'-bipheny1-
2,2'-diyl, 5,5'-
diisopropy1-1,1'-biphenyl-2,2'-diyl, 5,5'-di-n-butyl-1,11-bipheny1-2,2'-diyl,
5,5'-di-sec-butyl-
1,1'-bipheny1-2,2'-diyl, 5,5'-diisobuty1-1,11-bipheny1-2,2'-diyl, 5,5'-di(1,1-
dimethylethyl)-1,1'-
bipheny1-2,2'-diyl, 5,5'-di-n-amyl-1,1'-bipheny1-2,2'-diyl, 5,5'-bis(1,1-
dimethylpropy1)-1,1'-
bipheny1-2,2'-diyl, 5,5'-bis(1,1-dimethylpropy1)-1,1-bipheny1-2,2'-diyl, 5,5'-
di-n-hexy1-1,1'-
bipheny1-2,2'-diyl, 5,5'-di-2-hexy1-1,1'-bipheny1-2,2'-diyl, 5,5'-di-3-hexy1-
1,1'-bipheny1-2,2'-
diyl,
5,5'-di-2-hepty1-1,1'-bipheny1-2,2'-diyl, 5,5'-di-3-
hepty1-1,11-bipheny1-2,2'-diyl, 5,5'-di-4-hepty1-1,1'-bipheny1-2,2'-diyl,
bipheny1-2,2'-diyl, 5,5'-di-2-octy1-1,1'-bipheny1-2,2'-diyl, 5,5'-di-3-octy1-
1,1'-bipheny1-2,2'-
diyl, 5,5'-di-4-octy1-1,1'-bipheny1-2,2'-diyl, 5,5'-bis(1,1,3,3-
tetramethylbuty1)-1,1'-bipheny1-
2,2'-diyl, 5,5',6,6'-tetramethy1-1,1'-bipheny1-2,2'-diyl, 5,5'-dipheny1-1,1'-
bipheny1-2,2'-diyl,
CA 02862041 2015-11-27
5,5'-bis(2,4,6,-trimethylpheny1)-1,1'-bipheny1-2,2'-diyl, 5,5'-dimethoxy-1,1'-
bipheny1-2,2'-diyl,
5,5'-diethoxy-1,1'-bipheny1-2,2'-diyl, 5,5'-di-n-propoxy-1,1'-bipheny1-2,2'-
diyl, 5,5'-
diisopropoxy-1,1'-bipheny1-2,2'-diyl, 5,5'-di-n-butoxy-1,1'-bipheny1-2,2'-
diyl, 5,5'-di-sec-
butoxy-1,1'-bipheny1-2,2'-diyl, 5,5'-diisobutoxy-1,1'-bipheny1-2,2'-diyl, 5,5'-
di-tert-butoxy-
5 1,11-bipheny1-2,2'-diyland 1,1'-binaphthaliny1-2,2'-diyl.
The groups
R12
R5
Rii = = R6
R9
Rio R9 R7
are particularly preferably both 1,1'-bipheny1-2,2'-diyl.
The method of the invention is particularly preferably suitable for purifying
the following
organic diphosphites:
(CH3)3C C(CH3)3
411
(CH3)3C C(CH3)3
0 0
40 0-7 _oO
1
0 0
410
CA 02862041 2015-11-27
31
(CH3)3C CH3 H3C C(CH3)3
= .
(CH3)3C C(CH3)3
0 0
/ \
* 0-7 P-0 0
I
0 0
= .
CH30 OCH3
II .
(CH3)3C C(CH3)3
0 0
/ \
$ 01 P-0 0
O
0
= .
(CH3)3C C(CH3)3
= =
CH30 OCH3
0 0
/ \
* 0¨p P-0 =
oI
0
. .
CA 02862041 2015-11-27
32
111
/0 O\
o
40 0-17 P-0 410 I
0
ÖÖ
In particular, the organic diphosphite of the formula (I) is 6,6'4[3,3',5,5'-
tetrakis(1,1-
dimethylethyl)-1,11-biphenyl]-2,2'-diylibis(oxy)]bis-
dibenzo[d,f][1,3,2]dioxaphosphepin.
Step a)
In a preferred embodiment of the method of the invention, the solution of a
crude organic
diphosphite provided in step a) is a reaction output from the preparation of
organic
diphosphites.
The solution of a crude organic diphosphite provided in step a) is preferably
a reaction
output from a production process as described in EP 0 214 622 A2, US
4,668,651,
US 4,748,261, US 4,769,498, US 4,885,401, US 5,235,113, US 5,391,801, US
5,663,403,
US 5,728,861, US 6,172,267, WO 2003/062171 and WO 2003/062251.
In a preferred embodiment, the solution of a crude organic diphosphite
provided in step a)
is a reaction output from a production process as described in WO 2003/062171
and WO
2003/062251.
The solution of a crude organic diphosphite provided in step a) preferably has
a solvent
selected from among toluene, ethylbenzene, o-, m- or p-xylene, cumene, anisole
and
mixtures thereof. In particular, a solvent comprising toluene or consisting of
toluene is
used. Of course, it is also possible to subject a reaction output from the
preparation of the
CA 02862041 2015-11-27
33
organic diphosphites to a solvent exchange in order to provide the solution of
a crude
organic diphosphite in step a). However, such a procedure is not preferred.
The preparation of the diphosphites used according to the invention for
purification may in
principle be carried out by means of a sequence of known phosphorus halide-
alcohol
condensation reactions.
A specific embodiment is a process in which an organic diphosphite (I)
R11
R2 R3 R6
R10 lel R12 R5 R7
R4
R
/0 el R8 9
O¨P
p¨O 40
R7 05
R8
R4 R3 R2rµ 4100 Ri
n12 R1 R9
0
R6
(I)
where R1, R2, R3 and R4, R5, R6, R7, Rs, R9, R10, R11 and rc ^12
are as defined above,
is prepared by
i) reacting a diol of the general formula (Ai)
R12 OH HO R5
R11 41
Rio
R9 R8 R7
R6 (Ai)
with PCI3 to give a compound (A1)
CA 02862041 2015-11-27
34
CI
R12 0 0 R5
R111
R6 Rs R7 (A1)
R9
Rio
ii) reacting at least one compound (A1) with a diol of the general
formula (Aii)
R2 R3
R1 R4
(Aii)
O
HO H
Ra
R3 R2
to give the organic diphosphite (l).
As regards suitable and preferred embodiments of the radicals R1, R2, R3, R4,
R5, Rs, R7,
R8, Rs, R10, R11 and R12, what has been said above with regard to these
radicals is fully
incorporated by reference.
As solvent for preparing the organic diphosphites, preference is given to
using a solvent or
solvent mixture which corresponds to the above-described first solvent (L1).
At least one of the steps i) or ii) is preferably carried out in the presence
of a base.
Suitable bases are generally, for example, alkali metal hydroxides, alkaline
earth metal
hydroxides, alkali metal carbonates, alkaline earth metal carbonates, alkali
metal
hydrogencarbonates, alkaline earth metal hydrogencarbonates, tertiary amines,
basic ion-
exchange resins, etc. These include, for example, NaOH, KOH, Ca(OH)2,
triethylamine,
tripropylamine, tributylamine, etc. Preference is given to tertiary amines and
especially
triethylamine.
CA 02862041 2015-11-27
Particular preference is given to a method in which at least one of the steps
i) or ii) is
carried out in the presence of a base selected from among bases which with the
hydrohalic acid formed in the respective reaction step form a salt which is
liquid at
temperatures at which the reaction product of the respective reaction step is
not
5 significantly decomposed during the removal of the liquid salt and the
salt forms two
immiscible liquid phases with the reaction medium of the respective reaction
step.
Suitable bases of this type are described in WO 2003/062171 and WO
2003/062251.
Preferred bases of this type are 1-methylimidazole, 1-n-butylimidazole, 2-
methylpyridine
10 and 2-ethylpyridine.
In the latter method variant, the major part of the acid salts formed in the
condensation
reactions from hydrohalic acid and base can advantageously be removed by
simple phase
separation. Nevertheless, subsequent purification of the reaction output from
the
15 purification method of the invention has an advantageous effect on the
organic diphosphite
(I) obtained. In this way, it is possible to achieve a further significant
reduction in the
proportion of the abovementioned impurities.
In a preferred embodiment, the reaction in step i) is carried out in the
presence of a
20 catalytic amount of an acid salt of a nitrogen base. The acid salt is
preferably derived from
a nitrogen base selected from among in each case unsubstituted or substituted
imidazoles, pyridines, 1H-pyrazoles, 1-pyrazolines, 3-pyrazolines,
imidazolines, thiazoles,
oxazoles, 1,2,4-triazoles and 1,2,3-triazoles. The acid salt is particularly
preferably derived
from an acid selected from among hydrogen chloride, p-toluenesulfonic acid,
25 methanesulfonic acid, 2,4,6-trimethylbenzoic acid and
trifluoromethanesulfonic acid. In
particular, N-methylimidazolium hydrochloride is used.
Step b1) (= method variant 1)
30 According to the invention, in this method variant the organic
diphosphite is partly
precipitated by partial removal of the first solvent (L1) and the second
solvent (L2) is
added to complete the precipitation.
CA 02862041 2015-11-27
36
The partial removal of the first solvent (L1) can be effected by conventional
methods
known to those skilled in the art. These include evaporation under reduced
pressure
and/or at elevated temperature.
The solvent (L1) is preferably removed to an extent of at least 10% by weight,
preferably at
least 20% by weight, in particular at least 30% by weight, based on the amount
originally
used. If toluene is used as first solvent (L1), this is especially removed to
an extent of at
least 50% by weight, more particularly to an extent of at least 60% by weight,
based on the
amount originally used.
The solvent (L1) is preferably removed to an extent of not more than 95% by
weight,
particularly preferably not more than 90% by weight, based on the amount
originally used.
The organic diphosphite partly precipitates during removal of the solvent
(L1).
In a preferred embodiment, the composition comprising the first solvent (L1)
and the partly
precipitated organic diphosphite is cooled before the addition of the second
solvent (L2)
and the temperature is kept low during the addition of the second solvent
(L2). The
temperature during the addition of the second solvent (L2) is preferably not
more than
20 C, particularly preferably not more than 15 C.
Step b2) (= method variant 2)
The solution provided in step a) preferably has a temperature in the range
from 50 to
180 C, preferably from 60 to 150 C, in particular from 70 to 130 C, on
addition to the
second solvent in step b2).
The second solvent in step b2) preferably has a temperature in the range from
0 to 50 C,
preferably from 15 to 45 C, in particular from 15 to 30 C, when the addition
occurs.
In step b2), the temperature difference when the solution provided in step a)
is added to
the second solvent is preferably at least 20 C, more preferably at least 30 C,
in particular
at least 40 C.
CA 02862041 2015-11-27
37
In a preferred embodiment, the second solvent (L2) is placed in a reaction
vessel in step
b2) and the solution of the organic diphosphite provided in step a) is fed as
feed stream
into the space above the initially charged solvent (L2).
This can be achieved using a conventional addition device whose outlet opening
ends
above the initially charged solvent (L2). The addition can be effected in the
form of
individual droplets or in the form of a jet. The amount fed in can be
regulated by means of
a conventional metering device, e.g. a valve, metering pump, etc. If a hot
solution of the
organic diphosphite is added to the initially charged solvent (L2), the
addition device can
be fully insulated.
The addition of the solution of the organic diphosphite to the solvent (L2) is
advantageously carried out so that it occurs in free fall, i.e. without
touching the walls and
without touching the stirrer blades, so that lump formation is avoided.
Step c)
According to the invention, the precipitated organic diphosphite is separated
off from the
liquid phase in step c) according to both the abovementioned method variants.
The separation can be carried out, for example, by filtration or
centrifugation. The
separation is preferably carried out by filtration. Customary filtration
methods are, for
example, cake filtration and deep bed filtration (e.g. as described in A.
Rushton,
A. S. Ward, R. G. Holdich: Solid-Liquid Filtration and Separation Technology,
VCH
Verlagsgesellschaft, Weinheim 1996, pages 177 ff., K. J. Ives, in A. Rushton
(ed.):
Mathematical Models and Design Methods in Solid-Liquid Separation, NATO ASI
Series E
No. 88, Martinus Nijhoff, Dordrecht 1985, pages 90 ff.) and Cross-flow
Filtrations (e.g. as
described in J. Altmann, S. Ripperger, J. Membrane Sci. 124 (1997), pages 119-
128). To
accelerate the filtration, it can be carried out under increased pressure on
the solids side
or reduced pressure on the outflow side. Customary centrifugation methods are
described,
for example, in G. Hultsch, H. Wilkesmann, "Filtering Centrifuges," in D. B.
Purchas, Solid -
Liquid Separation, Upland Press, Croydon 1977, pp. 493-559; and H. Trawinski
in "Die
CA 02862041 2015-11-27
38
aquivalente Klarflache von Zentrifugen", Chem. Ztg. 83 (1959), 606-612.
Various
construction types such as tube centrifuges and basket centrifuges and also
pusher
centrifuges and invertible filter centrifuges and plate separators can be
used.
The liquid phase separated off in step c) can, if desired, be subjected to a
work-up. In a
preferred embodiment of the method of the invention, the liquid phase is
subjected to a
separation into a fraction (C1) comprising essentially the first solvent (L1)
and the second
solvent (L2) and a fraction (C2) comprising essentially the impurities. For
this purpose, the
first and second solvents (L1 and L2) can, for example, be at least partly
separated off
from the liquid phase by vaporization. Suitable separation apparatuses are the
distillation
columns and evaporators customary for this purpose, e.g. falling film
evaporators, forced
circulation flash evaporators, short path evaporators or thin film
evaporators. Owing to the
low volatility of most impurities, complicated apparatuses as are used in the
separation of
mixtures having boiling points close to one another, e.g. complicated column
internals,
columns having a large number of theoretical plates, etc., can generally be
dispensed with.
The fraction (C1) comprising the first solvent (L1) and the second solvent
(L2) can be
subjected to a further separation into a fraction (C1L1) comprising
essentially the first
solvent (L1) and a fraction (C1L2) comprising essentially the second solvent
(L2). Suitable
apparatuses for the work-up by distillation comprise distillation columns such
as tray
columns which can be equipped with bubble caps, sieve plates, sieve trays,
packings,
random packing elements, valves, side offtakes, etc., evaporators such as thin
film
evaporators, falling film evaporators, forced circulation evaporators, Sambay
evaporators,
etc., and combinations thereof.
The fractions (C1 L1) and/or (C1L2) can be reused as first solvent (L1) and/or
as second
solvent (L2) for purifying organic disphosphites by the method of the
invention. Here, it is
generally not critical if the second solvent (L2) comprises small proportions
(e.g. up to
about 5% by weight) of the first solvent (L1).
The fraction (C2) comprising essentially the impurities is discharged from the
method. It
can, for example, be passed to thermal utilization.
CA 02862041 2015-11-27
39
The organic diphosphite obtained in step c) of the method of the invention has
a sufficient
purity for use as ligand in homogeneous catalysis. However, it can be
advantageous,
especially for use in a continuous catalytic process, for the organic
diphosphite separated
off in step c) to be subjected to further washing in step b).
Step d)
In a specific embodiment of the method of the invention, the organic
diphosphite obtained
in step c) is subjected to a further work-up by washing with a liquid washing
medium.
Treatment with a liquid washing medium has been found to be advantageous both
for the
crystalline organic diphosphites obtained according to method variant 1 (steps
a), b1) and
c)) and for those obtained according to method variant 2 (steps a), b2) and
c)). In the case
of the organic diphosphites obtained according to method variant 2 (steps a),
b2) and c)),
no further purification in addition to a single or multiple treatment with a
liquid washing
medium is necessary.
If the organic diphosphites obtained according to method variant 1 (steps a),
b1) and c))
still comprise small amounts of occluded solvents and/or small amounts of
impurities, they
can be subjected to an additional work-up comprising a recrystallization in
step d). A
combination of a recrystallization and a treatment with a liquid washing
medium is
preferred in variant 1).
Suitable washing media are those mentioned above. A particularly preferred
washing
medium is methanol.
The treatment of the organic diphosphite with a washing medium is preferably
carried out
at ambient temperature. The treatment of the organic diphosphite with a
washing medium
is more preferably carried out at a temperature of at least 15 C, particularly
preferably at a
temperature of from 15 to 20 C. The treatment of the organic diphosphite with
a washing
medium is preferably carried out at a temperature of not more than 30 C.
CA 02862041 2015-11-27
To remove the impurities comprised, the organic diphosphite obtained in step
c) can be
subjected once or a plurality of times in succession to a treatment with a
washing medium.
For this purpose, the organic diphosphite is brought into intimate contact
with the washing
medium in a suitable apparatus and the washing medium is subsequently
separated off
5 from the organic diphosphite. Suitable apparatuses are, for example,
stirred vessels which,
if necessary, can be provided with a heating facility and a facility for
condensing and
recirculating the washing medium. Another suitable apparatus is a suction
filter on which
the filter cake is washed with the washing medium. The separation of organic
diphosphite
from the washing medium is carried out, for example, by filtration or
centrifugation. To
10 accelerate the filtration, it can be carried out under increased
pressure on the solids side
or reduced pressure on the outflow side.
As mentioned above, a base is preferably added to the washing medium. In the
case of a
plurality of washing steps, the base can be added in one or more of the
washing steps.
15 This applies, for example, in the case of a plurality of washing steps
to the washing
medium used in the last washing step. If the organic diphosphite is firstly
subjected to
single or multiple washing with methanol and subsequent washing with acetone,
the base
is preferably added in at least one of the washing steps using methanol. The
base is
particularly preferably added in all washing steps using methanol. In a
preferred
20 embodiment, the organic diphosphite obtained in step c) is firstly
subjected to single or
multiple washing with basic methanol and subsequent washing with acetone to
displace
the methanol and displace residues of base.
Suitable bases are those mentioned above as additive to the washing medium. An
alkali
25 metal alkoxide, in particular sodium methoxide, is preferably used as
base.
In a specific embodiment, methanol to which sodium methoxide has been added is
used
as washing medium.
30 A base is preferably added to the washing medium in an amount of from
0.01 to 10% by
weight, particularly preferably from 0.05 to 1% by weight, in particular from
0.05 to 0.5% by
weight, based on the total weight of the second solvent (L2).
CA 02862041 2015-11-27
41
The washing medium loaded with impurities can, for example, be worked up by
distillation
and be reused as washing medium. Impurities which have been separated off are
discharged.
The compounds of the general formula (I) obtained by the purification method
of the
invention are advantageous as ligands for catalysts in continuous processes.
Here, the
disadvantages associated with an accumulation of the abovementioned
impurities, in
particular a reduction in the catalyst operating life, can be significantly
reduced. The
compounds of the general formula (I) obtained by the purification method of
the invention
also display good flowability. In addition, they display a low tendency to
cake and can also
be stored over long periods of time. Mechanical comminution before use is
advantageously not necessary in many cases.
The compounds of the general formula (I) obtained by the purification method
of the
invention are advantageous as ligands for transition metal catalysts for
hydroformylation,
hydrocyanation or hydrogenation.
In general, the metal concentration in the reaction medium is in the range
from about 1 to
10 000 ppm. The molar ratio of ligand to transition metal is generally in the
range from
about 0.5:1 to 1000:1, preferably from 1:1 to 500:1.
A person skilled in the art will select the transition metal as a function of
the reaction to be
catalyzed. The transition metal is preferably a metal of group 8, 9 or 10 of
the Periodic
Table of the Elements. The transition metal is particularly preferably
selected from among
the metals of groups 9 and 10 (i.e. Co, Ni, Rh, Pd, Ir, Pt).
The catalysts used in one of the abovementioned processes can further comprise
at least
one further ligand which is preferably selected from among carboxylates,
acetylacetonate,
arylsulfonates, alkylsulfonates, hydride, CO, olefins, dienes, cycloolefins,
nitriles,
aromatics and heteroaromatics, ethers and monodentate, bidentate and
polydentate
phosphoramidite and phosphite ligands in addition to the above-described
compounds of
the formula (I). The further ligands are especially selected from among
hydride, CO and
CA 02862041 2015-11-27
42
olefins, i.e. components which are able to form, together with the diphosphite
(I) and the
central atom, the active form of the catalyst under hydroformylation
conditions.
In a preferred embodiment, the catalysts used according to the invention are
prepared in-
situ in the reactor used for the reaction. However, if desired, the catalysts
can also be
prepared separately and be isolated by conventional methods. To prepare the
catalysts
according to the invention in situ it is possible, for example, to react at
least one ligand
which has been purified according to the invention, a compound or a complex of
a
transition metal, optionally at least one further additional ligand and
optionally an activator
in an inert solvent under the conditions of the reaction to be catalyzed.
Suitable catalyst precursors are very generally transition metals, transition
metal
compounds and transition metal complexes.
Suitable rhodium compounds or complexes are, for example, rhodium(II) and
rhodium(III)
salts, e.g. rhodium(II) or rhodium(III) carboxylate, rhodium(II) and
rhodium(III) acetate, etc.
Rhodium complexes such as biscarbonylrhodium acetylacetonate,
acetylacetonatobisethylenerhodium(I),
acetylacetonatocyclooctadienylrhodium(I),
acetylacetonatonorbornadienylrhodium(I),
acetylacetonatocarbonyltriphenylphosphinerhodium(I), etc., are also suitable.
Suitable cobalt compounds for preparing the hydroformylation catalysts are,
for example,
cobalt(II) sulfate, cobalt(II) carbonate, amine or hydrate complexes thereof,
cobalt
carboxylates such as cobalt acetate, cobalt ethylhexanoate, cobalt
naphthanoate and
cobalt caproate. Carbonyl complexes of cobalt, e.g. octacarbonyldicobalt,
dodecacarbonyl
tetracobalt and hexadecacarbonyl hexacobalt, are also suitable.
The transition metal compounds and complexes mentioned and further suitable
transition
metal compounds and complexes are known in principle and are adequately
described in
the literature, or can be prepared by a person skilled in the art using
methods analogous to
those for the compounds which are already known.
CA 02862041 2015-11-27
43
The catalysts according to the invention are preferred for use in
hydroformylation. In the
case of hydroformylation catalysts, catalytically active species are generally
formed from
the catalysts or catalyst precursors used in each case under the
hydroformylation
conditions. For this purpose, an element of group 9 of the Periodic Table of
the Elements
and in particular rhodium or cobalt is preferably used as metal.
In the hydroformylation and/or the work-up of the catalysts, it is possible to
employ
measures which increase the catalytic activity and/or avoid decomposition of
the catalyst.
Such methods are described, for example, in EP 0 590 613, EP 0 865 418, EP 0
874 796,
EP 0 874 797, EP 0 876 321, EP 0 876 322, EP 0 904 259, EP 1 019 352 and
EP 1 019 353.
The hydroformylation can be carried out in a suitable solvent which is inert
under the
respective reaction conditions. Suitable solvents are, for example, the
aldehydes formed in
the hydroformylation and higher-boiling reaction components, e.g. the products
of aldol
condensation. Further suitable solvents are aromatics such as toluene and
xylenes,
hydrocarbons and mixtures of hydrocarbons, esters of aliphatic carboxylic
acids with
alkanols, for example TexanoI0, and esters of aromatic carboxylic acids, e.g.
C8-C13-
dialkyl phthalates.
As regards the preparation and use of hydroformylation catalysts, the teaching
of the
following documents is referenced: EP 0 214 622 A2, US 4,668,651, US
4,748,261,
US 4,769,498, US 4,885,401, US 5,235,113, US 5,391,801, US 5,663,403, US
5,728,861,
US 6,172,267, DE 103 60 771 A1, WO 2003/062171 and WO 2003/062251.
Suitable olefin starting materials for the hydroformylation process according
to the
invention are in principle all compounds which comprise one or more
ethylenically
unsaturated double bonds. They include olefins having terminal double bonds
and those
having internal double bonds, straight-chain and branched olefins, cyclic
olefins and
olefins which have substituents which are essentially inert under the
hydroformylation
conditions. Preference is given to olefin starting materials comprising
olefins having from 2
to 12, particularly preferably from 3 to 8, carbon atoms.
CA 02862041 2015-11-27
44
Suitable a-olefins are, for example, ethylene, propene, 1-butene, 1-pentene, 1-
hexene,
1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, etc.
Preferred
branched internal olefins are C4-C20-olefins such as 2-methyl-2-butene, 2-
methy1-2-
pentene, 3-methyl-2-pentene, internal heptene mixtures, branched, internal
octene
mixtures, branched, internal nonene mixtures, branched, internal decene
mixtures,
branched, internal undecene mixtures, branched, internal dodecene mixtures,
etc. Further
suitable olefins are C5-C8-cycloalkenes such as cyclopentene, cyclohexene,
cycloheptene,
cyclooctene and derivatives thereof, e.g. Ci-C20-alkyl derivatives thereof
having from 1 to 5
alkyl substituents. Further suitable olefins are vinylaromatics such as
styrene, 0(-
methylstyrene, 4-isobutylstyrene, etc. Further suitable olefins are the
esters, monoesters
and amides of a,f3-ethylenically unsaturated monocarboxylic and/or
dicarboxylic acids, e.g.
methyl 3-pentenoate, methyl 4-pentenoate, methyl oleate, methyl acrylate,
methyl
methacrylate, unsaturated nitriles such as 3-pentenenitrile, 4-pentenenitrile,
acrylonitrile,
vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl
ether, etc., vinyl
chloride, allyl chloride, C3-C20-alkenols, -alkenediols and -alkadienols, e.g.
allyl alcohol,
hex-1-en-4-ol, oct-1-en-4-ol, 2,7-octadieno1-1. Further suitable substrates
are dienes or
polyenes having isolated or conjugated double bonds. These include, for
example, 1,3-
butadiene, 1,4-pentadiene, 1,5-hexadiene, 1,6-heptadiene, 1,7-octadiene, 1,8-
nonadiene,
1,9-decadiene, 1,10-undecadiene, 1,11-dodecadiene, 1,12-tridecadiene, 1,13-
tetradecadiene, vinylcyclohexene, dicyclopentadiene, 1,5,9-cyclooctatriene and
butadiene
homopolymers and copolymers.
In a specific embodiment, an industrially available olefin-comprising
hydrocarbon mixture
is used in the hydroformylation process.
A preferred industrial olefin mixture is the 04 fraction. C4 fractions can be
obtained, for
example, by fluid catalytic cracking or steam cracking of gas oil or by steam
cracking of
naphtha. Depending on the composition of the C4 fraction, a distinction is
made between
the total C4 fraction (crude C4 fraction), the raffinate I obtained after 1,3-
butadiene has
been separated off and the raffinate 11 obtained after isobutene has been
separated off.
Raffinate 11 is particularly suitable as olefin-comprising hydrocarbon mixture
for the
hydroformylation.
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A particularly preferred industrial olefin mixture is the C3 fraction.
Propylene streams
suitable as starting material can comprise not only propene but also propane.
The propane
content is, for example, from 0.5 to 40% by weight, especially from 2 to 30%
by weight, of
propane.
5
The reaction conditions of the abovementioned processes are known in principle
to those
skilled in the art. A person skilled in the art can therefore find suitable
reactors and
reaction conditions in the literature relevant to the respective process and
adapt them
routinely. Suitable reaction temperatures are generally in the range from -100
to 500 C,
10 preferably in the range from -80 to 250 C. Suitable reaction pressures
are generally in the
range from 0.0001 to 600 bar, preferably from 0.5 to 300 bar. The processes
can generally
be carried out continuously, semicontinuously or batchwise. Preference is
given to
continuous processes. Suitable reactors for the continuous reaction are known
to those
skilled in the art and are described, for example, in Ullmanns Enzyklopadie
der
15 technischen Chemie, vol. 1, 3rd edition, 1951, p. 743 ff. Suitable
pressure-rated reactors
are likewise known to those skilled in the art and are described, for example,
in Ullmanns
Enzyklopadie der technischen Chemie, vol. 1, 3rd edition, 1951, p. 769 ff.
The compounds of the general formula (I) obtained by the purification method
of the
20 invention are advantageous as ligands for catalysts for hydrocyanation.
The catalysts used for hydrocyanation also comprise complexes of a metal of
transition
group VIII, in particular nickel, ruthenium, rhodium, palladium, platinum,
preferably nickel,
palladium and platinum and very particularly preferably nickel. The metal
complexes can
25 be prepared as described above. The same applies to the in-situ
preparation of the
hydrocyanation catalysts according to the invention. Hydrocyanation processes
are
described in J. March, Advanced Organic Chemistry, 4th edition, pp. 811-812.
As regards the preparation and use of hydrocyanation catalysts, US 6,127,567
is
30 referenced.
The organic diphosphites which have been purified by the method of the
invention are also
advantageous as ligands of a hydrogenation catalyst. The catalysts according
to the
CA 02862041 2015-11-27
46
invention used for hydrogenation preferably comprise at least one metal of
group 9 or 10
of the Periodic Table of the Elements, i.e. a metal selected from among Rh,
Ir, Ni, Co, Pd
and Pt.
The amount of catalyst to be used depends, inter alia, on the respective
catalytically active
metal and on the form in which it is used and can be determined in each
particular case by
a person skilled in the art. Thus, for example, an Ni- or Co-comprising
hydrogenation
catalyst is used in an amount of preferably from 0.1 to 70% by weight,
particularly
preferably from 0.5 to 20% by weight and in particular from 1 to 10% by
weight, based on
the weight of the compound to be hydrogenated. The amount of catalyst
indicated relates
to the amount of active metal, i.e. to the catalytically active component of
the catalyst.
When noble metal catalysts comprising, for example, rhodium, ruthenium,
platinum or
palladium are used, amounts which are smaller by a factor of about 10 are
used.
The hydrogenation is preferably carried out at a temperature in the range from
0 to 250 C,
particularly preferably in the range from 20 to 200 C and in particular in the
range from 50
to 150 C.
The reaction pressure in the hydrogenation reaction is preferably in the range
from 1 to
300 bar, particularly preferably in the range from 50 to 250 bar and in
particular in the
range from 150 to 230 bar.
Both the reaction pressure and the reaction temperature depend, inter alia, on
the activity
and amount of the hydrogenation catalyst used and can be determined in each
particular
case by a person skilled in the art.
The hydrogenation can be carried out in a suitable solvent or undiluted in
bulk. Suitable
solvents are those which are inert under the reaction conditions, i.e. neither
react with the
starting material or product nor are changed themselves, and can be separated
off without
problems from the isoalkanes obtained. Suitable solvents include, for example,
open-chain
and cyclic ethers such as diethyl ether, methyl tert-butyl ether,
tetrahydrofuran or 1,4-
dioxane and alcohols, in particular Ci-C3-alkanols such as methanol, ethanol,
n-propanol
or isopropanol. Mixtures of the abovementioned solvents are also suitable.
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The hydrogen required for the hydrogenation can be used either in pure form or
in the form
of hydrogen-comprising gas mixtures. However, the latter must not comprise any
damaging amounts of catalyst poisons such as sulfur-comprising compounds or
CO.
Examples of suitable hydrogen-comprising gas mixtures are those from the
reforming
process. However, hydrogen is preferably used in pure form.
The hydrogenation can be carried out either continuously or batchwise.
The hydrogenation is generally carried out with the compound to be
hydrogenated being
initially charged, optionally in a solvent. This reaction solution is
subsequently preferably
admixed with the hydrogenation catalyst before the introduction of hydrogen is
then
commenced. Depending on the hydrogenation catalyst used, the hydrogenation is
carried
out at elevated temperature and/or superatmospheric pressure. The reaction
under
superatmospheric pressure can be carried out using the customary pressure
vessels
known from the prior art, e.g. autoclaves, stirring autoclaves and pressure
reactors. If a
superatmospheric pressure of hydrogen is not employed, the customary reaction
apparatuses of the prior art which are suitable for atmospheric pressure can
be used.
Examples are conventional stirred vessels which are preferably provided with
evaporative
cooling, suitable mixers, introduction devices, optionally heat-exchange
elements and inert
gas blanketing facilities. In the continuous mode of operation, the
hydrogenation can be
carried out under atmospheric pressure in reaction vessels, tube reactors,
fixed-bed
reactors and the like which are customary for this purpose.
The invention is illustrated by the following, nonlimiting examples.
Examples
Example 1
Synthesis of 6-chlorodibenzo[df][1,2,3]dioxaphosphepin using methylimidazolium
hydrochloride as catalyst
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48
2,2'-Dihydroxybiphenyl (931.1 g, 5.0 mol) and 1-methylimidazolium
hydrochloride (0.9 g,
7.6 mmol) were placed under nitrogen in a 2000 ml double-walled reactor and,
after
melting of the 2,2'-dihydroxybiphenyl, heated to an internal temperature of
142 C. The
introduction of phosphorus trichloride (861.2 g, 6.26 mol) was then commenced
while
stirring, with it being ensured that the phosphorus trichloride did not get
onto the hot
reactor wall. The rate of introduction was regulated so that the attached HCI
scrubbing
tower could absorb all of the HCI formed. A total of three hours were required
for the
addition of the phosphorus trichloride. After the addition of the phosphorus
trichloride, the
mixture was stirred at 140 C for another three hours and a fluid yellow
reaction mixture
was obtained. The reactor was subsequently evacuated over a period of 40
minutes to a
final vacuum of 16 mbar in order to remove the excess phosphorus trichloride.
The last
residues of phosphorus trichloride were removed by stirring under reduced
pressure at
140 C/16 mbar and the mixture was subsequently cooled to 65 C. After admission
of
nitrogen, toluene (139.2 g) was added and the resulting 90% strength by weight
solution
(1390 g) of the product was drained into a screw-cap bottle and closed under
argon.
According to 31P-NMR, the product had a purity of 98.7%.
Example 2:
Synthesis of 6-chlordibenzo[d,f][1,3,2]dioxaphosphepin using N-
methylpyrrolidone as
catalyst
A 600 liter vessel provided with inclined-blade stirrer, condenser, offgas
discharge facility
via a scrubbing tower and a facility for generating vacuum was charged under
nitrogen
with 2,2'-dihydroxybiphenyl (88.0 kg, 473 mol) and N-methylpyrrolidone (0.337
kg, 3.4
mol). The mixture was melted by heating to an internal temperature of 140 C
and
phosphorus trichloride (88.5 kg, 644 mol) was then introduced at 140 C over a
total period
of 7 hours. The slightly endothermic reaction proceeded with vigorous HCI
evolution and
gentle reflux. After all of the phosphorus trichloride had been added, the
mixture was
stirred at 140 C for another 9 hours and was then cooled to an internal
temperature of the
vessel of 50 C. The vessel was subsequently slowly evacuated at 50 C to a
final pressure
of 20 mbar (condenser temperature 5 C) in order to remove the excess
phosphorus
trichloride. Excess phosphorus trichloride distilled off during this
evacuation. To complete
the removal of phosphorus trichloride, the vessel was subsequently heated to
an internal
CA 02862041 2015-11-27
49
temperature of 140 C and stirred at this temperature and 20 mbar for another
three hours.
The product obtained was then cooled to 90 C and used directly for the
synthesis in
example 3.
Example 3:
6,6'4[3,3',5,5'-Tetrakis(1,1-dimethylethyl)-1,1'-biphenyl]-2,2'-
diyl]bis(oxy)]bisdibenzo
[d,f][1,3,2]dioxaphosphepin
A solution of 3,3',5,5'-tetra(1,1-dimethylethyl)-1,1'-biphenyl-2,2'-diol (92.7
kg) in a mixture
of 1-methylimidazole (40.8 kg) and toluene (313.5 kg) was added to the melt of
6-
chlorodibenzo[d,f][1,3,2]dioxaphosphepin (118.4 kg) obtained according to
example 2 at
85 C over a period of 60 minutes while stirring. At the end of the addition,
two phases
were present and these were stirred at 80 C for another one hour. The internal
temperature was then increased to 90 C, the stirrer was switched off to allow
phase
separation and the phases were left to separate at 90 C for 20 minutes.
1-Methylimidazolium hydrochloride (59 kg) was obtained as lower phase and this
crystallized out immediately. A 31P-NMR of the upper phase remaining in the
vessel
confirmed that it was a solution of 6,6'1[3,3',5,5'-tetrakis(1,1-
dimethylethyl)-1,1'-biphenyl]-
2,2'-diyl]bis(oxy)]bisdibenzo[d,f][1,3,2]dioxaphosphepin in toluene. To carry
out purification
according to the above-described variant 1, the vessel contents obtained were
heated to
reflux (113 C) and stirred under reflux for three hours. Toluene was
subsequently distilled
off under atmospheric pressure (total 218 kg; the internal temperature in the
vessel at the
end of the distillation was 124 C). The contents of the vessel were then
cooled at a cooling
rate of 15 C/h to 70 C (stirrer speed: 50 rpm) and then cooled further at 10
C/h to 20 C.
Methanol (204 kg) was subsequently introduced at 20 C over a period of 5 hours
and the
mixture was stirred at 20 C for a further 30 minutes (stirrer speed 80 rpm).
The contents of
the vessel (white suspension) was then drained in equal parts into two
stainless steel
pressure filters. The further procedure for each pressure filter was then as
follows: the
mother liqor (toluene/methanol mixture) was then filtered off by
pressurization with
nitrogen. The filtration proceeded very quickly. To wash the filter cake on
each pressure
filter, fresh methanol (in each case 135 kg) was introduced into the vessel
and was stirred
at 18 C and a stirrer speed of 188 rpm for 10 minutes. The methanol was then
in each
case poured onto the pressure filter without stirring and filtration was again
carried out by
CA 02862041 2016-07-05
pressurization with nitrogen. The filter cake on each pressure filter was
subsequently
washed another four times with methanol (in each case 95 kg) and subsequently
blown
dry overnight by means of 2 bar of nitrogen until no more filtrate was
obtained. The
product on each pressure filter was subsequently dried further at a maximum of
50 C over
5 the course of 61 hours by means of a stream of nitrogen preheated to 50 C
until the
methanol content was less than 0.05%. The product (total 134.2 kg, yield
67.7%, based on
2,2'-dihydroxybiphenyl) was obtained as a white solid.
Chloride content (determined by means of ion chromatography): 13 mg/kg,
10 Nitrogen content (determined in accordance with ASTM D 5762-02): 37
mg/kg.
Example 4:
6,6'1[3,3',5,5'-Tetrakis(1,1-dimethylethyl)-1,11-bipheny1]-2,2'-
diyl]bis(oxy)]bisdibenzo
[d,f][1,3,2]dioxaphosphepin
A 2 I double-walled flask was charged under an inert atmosphere with 6-
chlorodibenzo-
[d,f][1,3,2]dioxaphosphepin (445.6 g as 90% strength solution in toluene, 1.60
mol) and the
solution was heated to 85 C. Furthermore, a 2 I conical flask provided with a
magnetic
stirrer was charged with 1-methylimidazole (141.0 g, 1.60 mol) and toluene
(791.5 g) and
3,3',5,5'-tetra(1,1-dimethylethyl)-1,1'-biphenyl-2,2'-diol (320.5 g, 0.78 mol)
was added to
the stirred mixture, resulting in formation of a virtually colorless solution.
This solution was
introduced dropwise under an inert atmosphere into the double-walled flask
over a period
of 80 minutes by means of a dropping funnel. The brown reaction mixture formed
was
subsequently maintained at 80 C for 50 minutes and then heated to 90 C. After
stirring for
another 10 minutes, the stirrer was stopped. Two phases had formed and these
were
allowed to separate for 70 minutes. The lower phase (1-methylimidazolium
hydrochloride)
was then drained as a viscose liquid (182.7 g) via the bottom valve and then
crystallized
very quickly (mp. about 80 C). The upper phase was then brought to reflux (115
C) and
stirred for a further 3 hours.
In the meantime, a 4 I double-walled reactor provided with a stirrer was
arranged
underneath the 2 I double-walled reactor and a thermally insulated Teflon TM
tube was
attached to the bottom outlet valve of the 2 I reactor and passed through a
ground glass
CA 02862041 2015-11-27
51
joint into the 4 I reactor. The 4 I reactor was charged under an inert
atmosphere with
methanol (2000 ml) and this was cooled to 20 C. The stirrer speed was
subsequently set
to 355 rpm and the solution of the ligand in toluene was allowed to run into
the methanol in
free fall from the 2 I reactor over a period of 70 minutes in such a way that
the stream
exiting from the Teflon tube came into contact neither with the wall nor with
the shaft or the
blade of the stirrer. The product precipitated immediately as a white solid.
After the
addition of the solution of the ligand was complete, the suspension obtained
was stirred for
another one hour. The product was subsequently filtered off and the 4 I
reactor was rinsed
with methanol (1000 m1). The filter cake was stirred up with this methanol and
filtered with
suction and washed another three times with methanol (in each case 1000 ml)
and then
sucked dry. Drying of the resulting product overnight at 70 C and 10 mbar gave
605.3 g
(90.1%, based on 6-chlorodibenzo[d,f][1,3,2]dioxaphosphepin) of a colorless,
free-flowing
powder
Chloride (ion chromatography): < 1 mg/kg, nitrogen (determined in accordance
with ASTM
D 5762-02): 2 mg/kg.
The product obtained directly after filtration was the toluene monosolvate of
6,6'1[3,3',5,5'-
tetrakis(1,1-dimethylethyl)-1,11-bipheny1]-2,2'-
diylibis(oxy)]bisdibenzo[d,f][1,3,2]dioxaphosphepin. Depending on the severity
of the
drying conditions, the toluene monosolvate can be converted into the
nonsolvate of I. The
toluene monosolvate and mixtures of these two forms of I in various
compositions
depending on the drying conditions are free-flowing powders which do not tend
to cake
even after prolonged storage.
Figure 1 shows the differential scanning calorimetry (DSC) measurement of the
methanol-
moist filter cake of I obtained in example 4 which has been sucked dry as far
as possible.
The DSC measurement was carried out using a Mettler Toledo DSC 822e module
(amount
of sample: 10 mg, open aluminum crucible, heating rate 10 K/min).
Despite the astonishing stability of 6,6'4[3,3',5,5'-tetrakis(1,1-
dimethylethyl)-1,11-bipheny1]-
2,2'-diyl]bis(oxy)]bisdibenzo[d,f][1,3,2]dioxaphosphepin in methanol which is
observed, it
was found that the methanol-moist filter cake of the pure product cannot be
subjected to
an excessively high thermal stress during drying since autocatalytic
decomposition in
CA 02862041 2015-11-27
52
which about 260 J/g of heat are liberated commences at an onset temperature of
157 C.
Overall, a final temperature of > 400 C is reached as a result of the
exothermic
decomposition.
Example 5:
Stabilization of 6,6'4[3,3',5,5'-tetrakis(1,1-dimethylethyl)-1,1'-biphenyl]-
2,2'-
diyllbis(oxy)]bisdibenzo[d,f][1,3,2]dioxaphosphepin by addition of sodium
methoxide to the
methanol in the precipitation and washing and also the final washing of the
filter cake with
acetone.
The solution of the ligand in toluene was produced in exactly the same way as
indicated in
example 4. The apparatus for the precipitation of l is the same as that
indicated in example
4. To carry out the precipitation, methanol (2000 ml) was placed in the 4 l
reactor and
sodium methoxide (8.0 g of a 30% strength solution in methanol) was added to
this. The
stirrer speed was subsequently set to 355 rpm and the solution of the ligand
in toluene
was allowed to run into the methanol in free fall from the 2 l reactor over a
period of 80
minutes in such a way that the stream exiting from the Teflon tube came into
contact
neither with the wall nor with the shaft or the blade of the stirrer. The
product precipitated
immediately as a white solid. After the addition of the solution of the ligand
was complete,
the suspension obtained was stirred for another 110 minutes. The product was
subsequently filtered off and the 4 l reactor was rinsed with a mixture of
methanol (450 g)
and sodium methoxide (2.0 g of a 30% strength solution in methanol). The
filter cake was
stirred up with this methanol and filtered with suction and washed another
three times with
a mixture of methanol and sodium methoxide (in each case 450 g of methanol and
2.0 g of
a 30% strength sodium methoxide solution in methanol) and then sucked dry. A
sample
(250 g) of the moist crystals of the filter cake was taken for a DSC
measurement and an
adiabatic reaction calorimetry measurement. Figure 2 shows the DSC.
The filter cake was subsequently washed by displacement washing with acetone
(500 ml)
and good suction was applied. After the product obtained in this way had been
dried at
70 C and 10 mbar for two days, 605.3 g of a colorless, free-flowing powder
were obtained.
CA 02862041 2015-11-27
53
If sodium methoxide is added to the methanol used in the purification and the
subsequent
washing steps and an acetone wash is then carried out at the end to displace
the Na0Me-
comprising methanol from the filter cake, differential calorimetry still shows
slight
decomposition above an onset temperature of 125 C but this no longer proceeds
autocatalytically. This procedure gives a product whose Na content is very low
(< 30 ppm)
and in which the risk of thermal decomposition is virtually completely ruled
out. The heat
evolution of about 54 J/g observed brings about heating of about 25 C which is
not
sufficient to heat the material further to a hazardous temperature range.
Example 6:
Storage tests on 6,6'4[3,3',5,5'-tetrakis(1,1-dimethylethyl)-1,11-biphenyl]-
2,2'-diylibis(oxy)]
bisdibenzo[d,f][1,3,2]dioxaphosphepin which has been purified according to the
invention
and which has been conventionally recrystallized
The product from example 4 is used as product according to the invention.
The product from example 1 which has been purified according to the invention
is
subjected to a storage test under relatively severe storage conditions with
the following
parameters:
high relative atmospheric humidity: 95%
high temperature: 40 C
water vapor-permeable packaging: Mini-Big Bags made of woven PP fabric with PE
inliner (material thickness 125 Jim), dimensions: 350 x 350 x 500 mm, volume
about
60 liters
high loading (such as three Mini-Big Bags above one another): 6.0 kPa
The experiments were carried out over two and four weeks.
The product is for this purpose packed in the above-described Mini-Big Bags
and, under
the indicated conditions in a controlled-atmosphere cabinet, subjected to the
appropriate
load by means of weights. After the period of time indicated, the Mini-Big
Bags are
removed from storage and cut open. Penetration tests are carried out on the
surface by
CA 02862041 2015-11-27
54
means of a penetrometer (PCE Inst. Deutschland GmbH) in order to determine the
penetration force.
a) Storage time two weeks:
slight clod formation on the surface
- some lumps in the core, remainder of the product is very free-flowing
lumps disintegrate again under a very small mechanical load
results of penetrometer test: (average of two samples at a different
penetration depth
with five measurements for each) 6 mm: 0.01 N, 12 mm: 0.3 N
b) Storage time four weeks:
- product is loose and free-flowing
- no caking
no too few lumps having a very low strength
- slight consolidation at the edge of the bag and especially in the corners
- results of penetrometer test: (average of two samples with five
measurements for
each) 6 mm: 0.0 N, 12 mm: 0.1 N
The product according to the invention precipitated from methanol as per
example 4 is
free-flowing and not at all caked even after four weeks. The highest
penetration forces
were measured after two weeks with a value of 0.3 N.
