Note: Descriptions are shown in the official language in which they were submitted.
It is known that aldehydes and alcohols can be pre-
pared by the reaction of olefin's with carbon monoxide and hydro-
gen which reaction is catalyzed by hydridometal carbonyls, pr~-
ferably those of the metals of the 8th ~roup of the Periodic
Table. Apart from cobalt which i.s'widely used.in industry as a
catalyst metal, rhodium has. a~so been gaining in:importance
recently. In contrast to cobalt, xhodium makes it possible for
the reacti.on to be carried out at low pressure and furthermore,
the reaction takes place wi.th enhanced formation of stffight-
chaine~ n-aldehydes with iso-aldehydes only being formed to a
minor de~ree. Finally, the hydxogenation of olefins to saturated
hydrocarbons is also appreciably lower w.ith rhodi.um catalysts
than with cobalt catalysts.
In the commerical processes, the rhodium catalyst is
in:the form of a modified h~drido~hodium.carbonyl containi~g
addi.tional ligands, if'n.ecessary in'excess. Ter:tiary phosphines
or phosphites ha~e pro~ed to be parti.cularly good as ligands and
by using them~ it'is'p~ssible to reduce.the reac:tion pressure
to values under 300'bar (3 x 104kPa). Howe~er,.the separati0n
of the reaction products and the recovery of the catalysts dis-
solved homo~eneously in the reaction product present problems
in'this'process. Generally, the reaction product is distilled
out of the reaction mixture, but this'method can only be used
in'practice for the hyd~oformylation.of low molecular weight
olefins, i.e. olefins with up to about 5 carbon atoms in the
molecule due to the thermal sensiti~ity of:the aldehyd.es and
alcohols formed. Furthermorer i.t.has been shown that the thexmal
loading of the distillation product also leads to considerable
catalyst losses due to decomposition of the rhodium complex
compounds.
The said shortcomings are avoided by the use of
catalyst systems which are soluble in'water and such catalysts
are,for example, described in the DE 26 27 354. Solubility of
the rhodium complex compounds is achieved by the use of sul-
fonated triarylphosphines as complex components. In this ver-
sion of the process, the catalyst is'separated ~rom the reac-
tion product a~ter completion of the hydroformylation reaction
simply by separation of the aqueous and organic'phases, i.e.
without distillation and thus without additional thermal process
steps. A further characteristic'o~ this method is'that n-alde-
hydes are formed with a high selecti~'ity from terminally unsatu-
rated olefins and iso-aldeh~des are ormed only to a minor
degree. Apart from sul~onated triarylphosphines, carboxylated
triarylphosphines are also used as complex components of ~ater-
soluble rhodium comple~ compounds.
The known processes have proved to be admirably suit-
able for the hydroformylation o~ lower olefins, in'particular
ethylene and propylene. However, if'higher oleEins such as
hexene, octene or decene are used, the conversio~ and/or the
selectivity towards n-compounds drop(s) appreciably. Thus,
the reaction is often no longer economical on a com~ercial
scale. The drop in'~ield is caused by the fact that higher
olefins are less s~luble in water since the reaction between
the two reactants takes place in'the aqueous phase.
Admittedly, DE 31 35 i27 does teach hydroformylation
of olefinic compounds in a system containing an aqueous phase
and an organic phase, which is ither immiscible or only sllg~tly
miscible with it in the presence of solubili~ers. The
practical performance of this'reaction is lim'ited exclusively
to the use of monosulfonated or monocarboxylated triarylphosphines
-2~
as a component of the rhodium complex compoundO It has been
shown that the monosulfo~ted triphenylphosphine in particular
leads only to a moderate conversion and that the selectivity
towards straigHt-chained n-aldehydes is low.
Conversion and selectivity can be improved by using
trisulfonated triarylphosphines instead of monosulfonated com-
pounds. However, an unsa,ti$factory aspect of this.~process
variant is that rhodi.um and water-soluble phosphine are removed
w.ith the organi.c'reaction product - even if only in small amounts-
so that in'many cases an additional working-up step is necessary.
A further disadvantage is.the related lowering of.the normal-
iso ratio.
It is an object of.the invention to ov,ercome the dis-
advantages of the prior art and develope , a procedure which also
permits the hydroformylation of higher olefins in a multi-phase
system consisting of aqueous catalyst solution and organic start-
ing materials and in'so~e cases reactio,n products as well as
gaseous reactants.
This'and other objects and advantages of the invention
will become obvious from the following detailed description.
In the novel process of,the i'nvention fo~,pr~pa~ation of
aldehydes by reacting olefins with carbon monoxide and hydrogen
in the liquid'phase in'the presence of water and rhodium in
metallic form or as a compound a.s well as a water-soluble aryl-
phosphine at temperatures of 20 to 150C and l.to 200 bar~(100 to
2 x 104 kPa)j the improvement comprï.s'es that the water-soluble
phosphin'e has the formula
~c~
A - N - C
L P \ Ar - Xx2 ¦ l D
where Ar is aryl and X is a sulfonic acid, xl, x2 and x 3 are
0 or 1 with the proviso that at least one of xl, x2 or x3 is 1, A
i5 selected from the group consisting o an alkyl o~ 1 to 18
carbon atoms and aralkyl of 7 to 18 carbon atoms and B,C,D are
alkyl of 1 to 4 carbon atoms and n is a whole number between
and 3.
Surprisingly, it has been proven that when waber-
soluble phosphines are used in the process of the invention the
high activity and selectivity of the catalyst system is maint-
ained even when high olefins are hydro~rmylated. At the same
time, however, the amount of phosphine removed with the organic
reaction product is also reduced considerably.
The water-soluble phosphinesused in the new process
obvi~usly improve the solubility of the organic substrate in the
aqueous phase and thus contribute towards an increase in the
conversion. Their extremely low solubility in the organic phase
means that they themselves and~he metallic components of the
catalyst system are either not removed with the reaction product
from the reaction zone, or if so, only a negligibly small amount~
Thus there is no need for a separate working-up step for the
recovery of rhodium from the aldehyde.
of the water-soluble phosphines of the above formula,
preferred compounds are those wherein Ar is phenyl or naphthylJ
the sum of xl, x2 and x3 is 2 or 3 and B,C and D are the same
alkyl of 1 to 4 carbon atoms.
--4--
Examples of water-soluble phosphines suitable for carrying out
the new process are triphenyl trisulfonates and triphenyldi---
sul~onates with.the~ollo~iny ca~i~ns: tr~hylc~tYla~oniu~ trimethyl-
dodecylammonium, tributyldodecylammonium, dodecylethyl-dimethyl-
ammonium, triethylbenzylammonium.
The phosphines used i.n:the claimed process are pre~
pared by treating sulfonated triar~lphosphines with oleum and
it is possible to prepare mono, di or trisulfonated arylphos-
phines by variation of the reaction conditions, particularly
the.reaction time, reaction temperature and the.ratio of tri-
arylphosphine to sulfuric: trioxide.
It is practical to first.reco~er amine s.alts from the
sulfonation product which are in'soluble in'water but soluble
in organic'solvents. They are then converted to the desired
"onium" salt of.the triarylphosphine by treatment with a quater-
nary ammonium hydroxi.de
The reac.tion of the olefin'w.ith hydrogen. and carbon
monoxid'e by the process o~ the inventi.oh takes place at tempera-
ture of 20 to 150~C, particularly S0 to 120C and pressures of ..
1 to 200 bar (100 to 2 x 104 kPa), particularly 10 to 100 bar
(1 x 103 to 1 x 104 kPa)~
The catalyst can be added to the reaction system in a
preformed state but it can also be successfully prepared in the
reaction mixture from the components.rhodium or a rhodium com-
pound and the aqueous solution of the quaternary ammonium salt
of the sulfonated triarylphosphine under reaction conditions,
i.e. in the presence of the olefin. In addit'ion to metallic
rhodium in finely distributed ~orm, water-soluble rhodium salts
such as rhodium chloride, rhodium sulfate, rhodium acetate or
compounds soluble in organic media such as rhodium-2-ethylhex-
--5--
anoate or insoluble compounds such as rhodium oxides can be used
as sources of rhodium.
The rhodium concentration in the aqueous catalyst
solution is 10 to 2000 ppm by weight based on the soluti~n. The
quaternary ammonium salt of the sulfonated phosphine is added in
such an amount that for 1 g atom of rhodium, 1 to 300 mol, pre-
ferably 2 to 100 mol, of phosphine compouna are present. The pH
value of the aqueous catalyst solution should not be below 2 and
generally, a pH value of 2 to 13, preferably 4 to 10 is
established.
The composition of the sy~thesis ~as, i.e. the ratio
of CO to hydrogen can be varied ~ithin wide limits. Generally,
a synthesis gas is used where the ~olume ratio of CO to hydrogen
is l : 1 or only deviates slightly from this value. The reaction
can be carried out both as a batch process and continuously. The
process of the invention is successfully used for hydroformyla-
tion of stright-chained or branched oleins of four or more
and in particular with six to twenty carbon atoms. The double
bond in these atoms can be terminal or internal.
The following examples ser~e to illustrate the inven-
tion more closely without limiting it to the embodiments dQscri-
bed therein. To characterize the efficiency of the catalyst
s,ystems, apart from the ratio of n-aldehyde to i-aldehyde, the
term "activity" is de~ined as
mol aldehyde
g-atom Rh x min
The formation of alcohols and hydrocarbons is minimal.
EXAMPLE 1 (Comparison)
420 g (corresponding to 355 ml3 of an aqueous solu-
tion containing 15.5% by weight of the sodium salt of tri~m-sul-
--6--
i3
fophenyl~ phosphine and 400 ppm of rhodium in the form of rhodium
acetate were placed in a l liter autoclave with a dip-pipe and
then, synthesis gas (CO/H2 = l:1) was orced in up to a pressure
of 25 bar. The reaction solution was treated with the synthesis
gas for 3 hours at 125C accompanied by stirring a~d it was then
cooled to about 30C. The stirring was stopped and after a
settling period of 15 minutes, the excess solution (~61 g) was
forced out th~gh the dip-pipe and analyzed and the residual
solution remained in the autoclave. After the resumption of .
stirring, 170 g of n-hexene-l were pumped through a pressure pipe
into the autoclave and while the pressure was maintained at 25
bar, the mixture was heated to 125C over a period of 3 hours.
It was then allowed to cool to 30C and settle. After a 15
minute settling p.eriod,.the uppermost organic phase was forced
out through the dip-pipe and was weighed and subjected to a gas
chromatographic analysis.
Hydroormylation was repeated a.total o~ 6.times where-
by more or less the same results were achieved. The activity
values listed in Table I relate to the amounts oE aqueous and
organic phase6present in the autoclave after each run.
7--
~2~
lP~ o ¦ o i
~ ~ ~o~P G ~
1- u~ tn O
3 ~ 4 ~ p o~ ~!
X ~. ~ o,
r~
- ~D
I_ ~- W Cl~ ~ ~_
1- I-p U~ ~ 1~
~t~ ,_~
1' 1' Ul ~ ~ ~
1~ ~P
~ O
~ o~
-;8
~%~
To determine the total amount of rhodium and phos-
phorus removed with the organic phase, the organic components
drawn off from the reactor in the individual tests were combined,
concentrated to about l/lOth of their original volume and analyzed.
0.017 ppm by weight of rhodium and 0.34 ppm by weight of phosphorus
(in each case based on the original organic phase) were found.
EXAMPLE 2
Example 1 was repeated with the exception that 315 g
(corresponding to 295 ml) of an aque~us solution of the trimethyl-
benæylammonium salt of tri-(m-sulfophenyl)phosphine with a P(III)
content of 0.308% hy weight and 158 g of n-hexene-l were used in
the hydroformylation process instead o~ the sodium salt. The test
results are reported in Table 2. The rhodium and phosphorus
losses were determined by the method described in Example 1. An
average of 0.029 ppm by weight of rhodium and 0.98 ppm by weight
of phosphorus were removed with the organic product, i.e. only
slightly more than when the normally employed sodium salt of tri-
(m-sulfophenyl)phosphine was used.
-
co ~ - ~o oo ~
~ o l`
a~
~1 ~D N
o Ln
(5 ~) ~I N
00
C~ O
:)
~1 ~
~D .
a~ ~ ,I N
O U~ ~1
. el~ Ln ~ N Ln ,~
N 'r ,J Ln
~i ~ Ln ~ NN 1`
~ ~') ~¦ 00 ~
N
~ N Ln 1`
E-~ cn ~
00 ~ In O ~r
~1 ~ r~
, a~
_ ~
Ul O ~
~: a) ~ .~
rl h ~ ~`1 k
_ a) ~ a) x
~1 C~ ~
ho ~ .~ ~ _,~ 8
4~ o~O
o Y U~ U~ ,,
h 1~ n~ h0
~ O O ~ ~ $ ~ ~
U~
O ~ h ~>
.
O O ~ h
Z ~ d O
__
~1.0--'
EXAMPhES 3 to 5
Examples 3 to 5 were carried ou-t by the method descri-
bed in Example 1 with the exception that instead of the sodium
salt of tri-(m-sulfophenyl)phosphine; 420:g (corresponding.to
390 ml) of an aqueous solution containing 46~ by weight of the
dodecylethyldim.ethylammonium salt of tri-'(m-sul~phenyl)phosphine
(Example 3); 820 g (corresponding to 740 ml) of an aqueous solu-
tion contain'ing 25% by weight of the benzyltrimethylammonium salt
of di-'~m-sulfophenyl)-phenylphosphine'(Example 4); 420 g (corres-
ponding to 39Q:ml) of an aqueous solution contain'ing 23~ byweigh't of the benzyltriethylammonium salt of.tri.-:(m-sulfophenyl)
phosphine (Example 5) were used. The.test.results are.reported
in Table 3.
5 `~
a
o ~ o o ,~
~o ~ o . ~ o ~ o
o ~
o ~ o
V~ o
,' a) . O v~
.
. o o
6~ . tu
~d ~t X . ~1 0 ~1
X rC ~ ~ ~
~ U~ o ~ o
W , ' : ~ o
.
., . " ~
; b4 1~ ~0
o o o
~ ~,, ~ ~ ~
. a~
.` ,1 ~ X ~ U~
a) r~ E~
~ ~ cn ~ . ~ .
E~ I t~ ~ .
E~
.
., ~ . .~ ,
.~ ~ o . ~
~ ~ ~ ~ , ~
,_ ~ X o ~ ;~ o
., ~ ~ o
~ ~ ~ a~
O
Ei ~ ~ .,~
' ~ o ~ V~ ~ .C
. ~I
~ ~ O ~ ~ a~ ~
~7 0 ~ ~ ' rC ~ C)
~ ~4 0 ~ ~ .r~ rl
E~ O O h .~ u h h
~ U ~ ~ ~
,,~ V) ~ ~ ~ ~ ~1 ~1
u ~ :~
O ~ ~ Ei
~rl ~ td
~ o In O a>
E- ~ O ~ U ~ ~ .n
a) u ~ ~d a
o ~ ,~
E- O ~ ~ z ~ ~ ~ u~
' ,
,
o ' ' ' , ' ,. . ~
ii3
EXAMPLES 6 and 7
Examples 6 and 7 were also carried out under the con-
ditions of Example 1 but with stYrene as the olefin. In ~xample
6 (comparison), the Na-salt (420 g corresponding to 375 ml of a
22~ by weight solution) and in Example 7, the dodecylethyldi-
methylammonium salt (420 g corresponding to 391 ml of a 23% by
weight solution) of tri-(m-sulfophenyl)-phosphine were used. The
results of the tests are reported in Table 4 and as can be
clearly seen, the quaternary ammonium salt favored the formation
of a-phenylpropionaldehyde.
-13-
o s`
O `D
u)
o ~
: ~ o
~ o
v~ o~o
o`
.
:~
~d ~
~ ~ o
' ' a) o
~ u~ ~
l-
' '' ~d ~ O ~ 11 ~0
~ l x ~ o o ~o o
o ~ ~
. ,:, E-
.
' ' ' ' ,~ ,~ ~ O
,u~ ~
) X tl~ rt h t~
~ ~ O ~ ~
' '' ' O ~d ~ ~ O O
o~ O n~ h ~ ~ ~
~ ~ ~ 4~ cd td ~
E~ o ~ ~ ~ u
O ~ H ~ U
-- O u) O
o ~ ~
O ~ ~SL ~ Z ~ ~O t
--14--
i`3
Various modifications of the process o~ the in~ention
may be made without departing rom the spirit or scope thereof
and it is to be understood that the invention is intended to
4 be limited only as deined in the appended claims.
-15-
