Note: Descriptions are shown in the official language in which they were submitted.
~1~8~33
PREPARATION OF POLYGLYCIDYI. ETHERS OF
POLYHYDRIC PHENOLS
The invention is concerned with a process for the
preparation of polyglycidyl ethers of polyhydric
phenols and with the polyglycidyl ethers so prepared.
It is known that polyglycidyl ethers can be
prepared by reaction of an epihalohydrin with a
polyhydric phenol~ for example, diphenylol methane,
novola~$,tetraphenylol ethane, and in particular
diphenylo propane~ which is also known as bisphenol
A, or 2,2-bis(4-hydroxyphenyl~propane. Diglycidyl
ethers of the latter can be represented by the formula:-
CH2_CH_CH2-O-R-O~CH2-,CH-CH2-O R ~n 2 \ / 2
wherein n is a number having an average value of from
0 to 15, and R is the hydrocarbon residue of the
dihydric phenol, that is the group of formula:-
Q ~ ( II~
'
1118433
An important class of such diglycidyl ethers arethe liquid grades - the technical products of formula
I which are liquid at room temperature; therein the
average value of n is low, preferably below 0.25, and
ideally is 0. In theory such liquid diglycidyl ethers
should have epoxide equivalent weights equal to half of
their molecular weights but in practice they tend to
be higher, for example due to the formation of poly-
meric by-products, or hydrolysis of glycidyl end groups.
It is well known that such diglycidyl ethers may
be prepared by reacting the dihydric phenol with an
epihalohydrin such as epichlorohydrin, in the presence
of an aqueous solution of an ionizable hydroxide, for
example an alkali-metal hydroxide such as sodium
hydroxide; it is also known that such reactions can be
carried out in the presence of an oxygen-containing
volatile organic solvent such as a ketone (acetone) or
an alcohol (isopropanol) (U.S. 2,848,435; U.S. 2,986,551/2
and U.S. 3,069,434. It is also well known that the use
of a molar excess of epihalohydrin such as from 5 to
20 moles for each mole of dihydric phenol, reduces the
formation of products of formula I wherein n is higher
then zero.
The reaction, wherein an excess of epichlorohydrin
and sodium hydroxide are used, may be represented by
the equation:-
2 C~ -~H-CH2-Cl + HO-R-OH + 2 NaOH >
o
1118433
CH\2 /CH C~12-O-R-O-CH2-C~I-CH2 1 2H20 1 2NaCl (III)
wherein R is as defined above.
It is generally accepted that the above reaction pro-
ceeds via two steps. The first step, sometimes referred to as
the condensation reaction, results mainly in the formation of
dichlorohydrins and may be represented by the equation:-
2 CH2-CH-CH2-Cl ~ HO-R-OH _aO~ CH2-CH-CH2-O-R-o-CH2-CH-CH2
O Cl OH OH Cl
(IV)
and the second step, sometimes referred to as the dehydrochlo-
rination reaction, results mainly in the removal of hydrogen
chloride from the dichlorohydrins and may be represented by the
equation:-
CH2-CH-CH2-O-R-O-CH2-,cH-c,H2 ~ 2 NaOH
Cl OH OH Cl
2/CH CH2 R CH2 C\H /H2 + 2 NaCl ~ 2H2 (V)
O O
In the reaction, sodium hydroxide functions both as the
condensation catalyst and as the dehydrohalogenating agent as do
ionizable hydroxides in general. It can be seen that, if no
products of formula I wherein n is 1 or higher are formed, the
reaction requires 2 moles of sodium hydroxide for each mole of
dihydric phenol although in practice a stoichiometric
~ i
18433
excess is mostly used.
It is known to carry out reaction III in such a
way that these two steps occur concomittently but it
has also been proposed to carry out the reaction in
5 stages in which the condensation reaction takes place
to a large extent before the dehydrohalogenation
reaction takes place. In such multistage processes it
has been proposed to stage the addition of the
ionizable hydroxide or to use in the first stage a
different condensation catalyst, such as an ionizable
chloride, bromide, iodide, sulphide or cyanide, which
is not capable of acting, to any appreciable extent, as
a dehydrohalogenating agent (U.K. 897,744; U.S.
2,943,095/6; U.S. 3,023,225; U.S. 3,069,434; U.S.
3,309,384; U.S. 3,221,032 and U.S. 3,352,825).
It should also be noted that the above reaction
produces water and sodium chloride, and processes are
known wherein the sodium chloride is allowed to dis-
solve in water and the brine is separated from the
organic phase. The brine, after the removal of any
unreacted epichlorohydrin and any oxygen-containing
volatile organic solvent therefrom, is usually dis-
carded although it has been proposed to use some of
it as a wàshing medium for the final reaction mixture
(U.S. 2,986,551). It has also been proposed to carry
out the dehydrochlorination reaction in two stages
with an intermediate brine removal stage (U.S.
1118433
3,023,225; U.S. 3,069,434 and U.S. 4,017,523) or an
intermediate epihalohydrin recovery stage (U.S.
2,841,595; U.K. 1,173,191~. It has also been proposed
to remove unreacted epichlorohydrin after the conden-
sation reaction but before the dehydrohalogenationreackion (U.K. 897,744).
The known processes for the production of poly-
glycidyl ethers usually suffer from one or more dis-
advantages such as the formation of an undesirable
amount of by-products e.g. polymeric compounds,
epihalohydrin hydrolysis products, solvent-derived
products etc.; the formation of polyglycidyl ethers
having an unacceptably high saponifiable chlorine
content; the loss of reactants and products in the
discarded brine, and the difficulty in operating
the process continually. The brine or brines contain
usually, apart from some epichlorohydrin and solvent,
resinous contaminants, which on an attempt to
recover the valuable volatile components by stripping
di~tillation, tend to contaminate the stripper column.
The reactions are sometimes extremely slow, and, in an
effort to improve the speed by raising the temperature,
side reactions can greatly afflict economic recovery
of epichlorohydrin, or the quality of the final resin.
We have now found a new process for the
preparation of polyglycidyl ethers which is substantial-
ly free of the above disadvantages. The new process
8433
allows easy operation, high recovery of solvent and
epihalohydrin, production of polyglycldyl ethers of
high quality, and of effluent low in alkalinity and
in organic contaminants.
The new process is a multi-stage process in which
at some stages a brine is separated and one or more
of these brines are recycled to an earlier stage in
the process; the new process may be carried out as
a continuous process or as a multi-stage batch process.
The invention can be defined as a process for the
preparation of a polyglycidyl ether of a polyhydric
phenol wherein the polyhydric phenol is reacted with
from 2.5 to 10 moles of an epihalohydrin per phenolic
hydroxy equivalent in the presence of a condensation
catalyst, water and a volatile organic solvent, and
the reaction product is reacted with aqueous alkali
metal hydroxide, with separation of aqueous phase
and organic phase in one or more stages and recovery
of the polyglycidyl ether from the last organic phase,
wherein at least part of at least one separated aqueous
phaBe iB recycled to an earlier stage of the process.
In a further definition the invention provides
a process for the preparation of polyglycidyl ethers
of polyhydric phenols comprising the steps of:-
(A) reacting in one or more stages(i) a polyhydric phenol;
(ii) an epihalohydrin in an amount of from 2.5 to
433
10 moles for each phenolic hydroxy equivalent
of (i); and
(iii) a condensation catalyst, with the proviso that
if the condensation catalyst contains an
ionizable hydroxide then the amount thereof
is at most 0.75 moles for each phenolic
hydroxy equivalent of (i);
(C) reacting in one or more stages the reaction
product obtained in step A with an aqueous solution
of an alkalimetal hydroxide, wherein the total amount
of alkali-metal hydroxide reacted, together with the
amount of ionizable hydroxide, if any, added in step
A, is at least 1.0 moles for each phenolic hydroxy
equivalent of (i) added in step A, separating the
reaction product, or each reaction product of each
stage, into an aqueous phase and an organic phase and,
if two or more reaction stages are used, reacting
each separated organic phase, with the exception of
the last organic phase, in the next reaction stage
? of this step C,
(D) recycling at least part of an aqueous phase
obtained in step C to step A or to one or more stages
thereof and/or to an earlier stage, if any, of step
C, and
(E) recovering the polyglycidyl ether of the poly-
hydric phenol from the organic phase or the last
organic phase obtained in step C.
3433
A preferred embodiment of the present invention
is a process for the preparation of polyglycidyl
ethers of polyhydric phenols comprising the steps
of:
(A) reacting in one or more stages, at a temperature
of below 75C,
(i) a polyhydric phenol;
(ii) an epihalohydrin in an amount of from 2.5 to
10 moles for each phenolic eqùivalent of (i);
; 10 in the presence of
(iii) an oxygen-containing volatile organic solvent
in such an amount that it represents from 20
to 200 %w based on the weight of (ii) and
- from 2 to 15 moles for each phenolic
; 15 equivalent of (i);
(iv) water in an amount of at least 15 %w based on
the weight of (ii), and
(v) a condensation catalyst, with the proviso that
if the condensation catalyst is an ionizable
hydroxide the amount thereof is at most 0.75
moles for each phenolic equivalent of (i);
(B) separating the reaction product obtained in step
A into an aqueous phase and an organic phase;
(C) reacting, in two or more stages, the organic phase
obtained in step B, at a temperature of below 75C,
with an aqueous solution of an alkali-mekal hydroxide,
wherein the amount of alkali-metal hydroxide added in
1118433
the first stage, together with the amount of ionizable
hydroxide, if any, added in step A, is less than 1.0
moles for each phenolic equivalent of (i) added in step
A and wherein the total amount of alkali-metal hydroxide
added, together with the amount of ionizable hydroxide,
if any, added in step A is at least 1.0 moles for each
phenolic equivalent of (i) added in step A, separating
the reaction product of each stage into an aqueous
phase and an organic phase and reacting each separated
organic phase with the exception of the last separated
organic phase, in the next reaction stage of this
step C;
(D) recycling at least a part of a separated aqueous
phase obtained in step C to step A or to one of the
stages thereof, and
(E) recovering the polyglycidyl ether of the poly-
hydric phenol from the last organic phase obtained
in step C.
The reaction step A may be carried out in
several stages. A single multi-stage reactor may be
used, for example of the type described in U.S.
3,129,232, or several separate reactors in series or
a combination of at least one single multi-stage
reactor and at least one separate reactor in series
may be used.
The polyhydric phenol for use in step A is
preferably a dihydric phenol, and more preferably a
1118433
di(hydroxyphenyl~-alkane of the general formula:-
HO ~ R2 OH (VI)
wherein R1 and R2 are H atoms or the same ordifferent C1 to C6 alkyl groups. Preferably the
hydroxyl groups are in both para-positions with respect
to the alkylene group. Examples include diphenylol-
methane (Bisphenol F), diphenylolethane, and diphenylol-
propane (Bisphenol A), the latter being preferred, andmixtures thereof, such as mixtures of the bisphenols
A and F, preferably in a 7O:3O weight ratio. Poly-
hydric phenols with more than 2, for example 3, 4, or
5, hydroxy aromatic groups per molecule, may also be
used in step A; examples are technical 1,1,2,2-tetra-
(4-hydroxyphenyl)ethane and novolacs.
The epihalohydrin for use in step A is suitably
epichlorohydrin or epibromohydrin with the former
being preferred. Preferred amounts of epihalohydrin
are from 3~5 to 8 moles for each phenolic equivalent
of polyhydric phenol.
If step A is carried out in two or more stages both
the epihalohydrin and the polyhydric phenol are added
to the first stage.
Suitable condensation catalysts for use in step
A are ionizable hydroxides, chlorides, bromides, io-
dides, sulphides and cyanides.
1~18433
11
The amount of condensation catalyst may vary
considerably, for example from 0.005 to 1.5 moles
for each phenolic equivalent of polyhydric phenol,
with the proviso that if an ionizable hydroxide is
used then the amounts thereof should not be more than
0.75 moles for each phenolic equivalent of polyhydric
phenol; in this case the amount of ionizable hydroxide
added in the first stage of step A is preferably from
0.025 to 0.425 moles, more preferably from 0.05 to
0.25 moles per phenolic equivalent of polyhydric phenol,
and the total amount of ionizable hydroxide added in
step A is pre~erably from 0.05 to 0.75 moles more
preferably from 0.25 to o.6 moles per phenolic equi-
valent of polyhydric phenol. It is preferred that if
substantially no ionizable hydroxide is added in step
A then the amount of the condensation catalyst is at
least 0.075 mole for each phenolic equivalent of poly-
hydric phenol. Preferred condensation catalysts are
in the ammonium or alkali-metal form. The more pre-
ferred condensation catalyst are the ammonium andalkali-metal hydroxides and halides. The preferred
halides are the chlorides and bromides with the former
being particularly preferred. Preferred ammonium
compounds are quarternary ammonium compounds such as
tetramethyl ammonium hydroxide, tetraethyl ammonium
hydroxide, tetramethyl ammonium chloride, methyl
triethyl ammonium chloride and benzyl trimethyl
433
ammonium chloride. Preferred alkali-metal compounds are the
hydroxides and chlorides of lithium, sodium and
potassium. The most preferred condensation catalysts
for use in step A are sodium hydroxide and/or sodium
chloride; a highly preferred condensation catalyst
in step A is a mixture of sodium hydroxide and sodium
chloride. Such a mixture is that present in the first
and optionally further aqueous phases obtained in step
C. Suitably the condensation catalysts are fed to
step A as aqueous solutions. If step A is carried out
in two or more stages the condensation catalyst, or
a part thereof, is added to the first stage, and
preferably condensation catalyst is added to each
stage.
An oxygen-containing volatile organic solvent
and/or waker may also be added in step A. In the
preferred embodiment of the present invention both an
oxygen-containing volatile organic solvent and water
are added in step A. Suitably the amount of oxygen-
containing organic solvent added is from 20 to 200 %w
ba~ed on the weight of the epihalohydrin with the
proviso that this amount should not be below 2 moles
or above 15 moles for each phenolic equivalent of
polydihydric phenol and suitably the amount of water
i8 at least 15 %w based on the weight of epihalohy-
drin. In this preferred embodiment the amount of water
is such that the reaction product mixture of step A
1118433
13
separates into two liquid phases, an organic phase
and an aqueous phase. Preferably the amount of water
is such that any ionizable halides added or formed
in step A are dissolved to produce a step A reaction
product mixture which is substantially free of solid
particles. Consequently the optimal amount of water
will depend upon the specific ionizable halide added
or formed. in general the amount of water should be
from 400 to 600 %w, based on the weight of ionizable
halide. In general there is no upper limit to the
amount of water added in step A although in practice
it will be restricted by such factors as optimal
reactor volume, solvent recovery costs, epihalohydrin
hydrolysis, etc. In practice the amount of added
water present may be from 30 to 60 %w based on the
weight of oxygen-containing volatile organic solvent.
In this preferred embodiment the water may be added
to step A in several ways e.g. it may be included in
a polyhydric phenol/oxygen-containing volatile organic
solvent, if any, feed stream and/or added as an aqueous
solution of condensation catalyst and/or added as a
recycled aqueous phase, obtained in step C, and/or
added as a recycled aqueous phase obtained in the
recovery step e.g. a recycled washwater and/or added
as a separate water stream. In this preferred em-
bodiment the use of too low an amount of oxygen-
containing volatile organic solvent will result in an
111~433
14
unacceptably low reaction rate in step A and the use
of too high an amount will result in highly viscous
products and unacceptably high solvent recovery costs.
The oxygen-containing volatile organic solvent should
be halogen-free and volatile, that is have a boiling
point at atmospheric pressure of preferably not above
120C and not below 50C; it should have one oxygen
atom per molecule; it should be an alcohol or a ketone,
and have preferably 3 to 6, more preferably 3 or 4,
carbon atoms per molecule; examples are the ketones
acetone and methyl ethyl ketone, and the alcohols
propanol, isopropanol, butanol, and isobutanol. Suita-
ble alcohols are in general the Cl to C6 alkanols,
such as methanol, ethanol; preferred is isopropanol.
Preferred amounts of oxygen-containing volatile organic
solvent are from 30 to 100 %w based on the weight of
the epihalohydrin. If step A is carried out in two
or more stages the oxygen-containing solvent and at
least the above minimum amount of water, that is at
lea8t 15 %w based on the weight of epihalohydrin, are
added in the first stage.
The reaction temperature of step A depends on
whether or not an oxygen-containing organic solvent
and/or water are added in step A, and the amounts
thereof, and on the type of condensation catalyst used
but in general will be at least 25C and preferably
from 35 to 120C. In the preferred embodiment of the
3433
present invention, using an oxygen-containing volatile
organic solvent and water in step A, the reaction
temperature is preferably below 75C, more preferably
from 35 to 65C. One o~ the attractive features of
the present process is that residence times in step
A below 6 hours are sufficient for an acceptable
conversion, and that generally the residence time
can be from 0.15 to 4.0 hours.
The total residence time in step A will depend
upon the reaction temperature. In the preferred em-
bodiment as defined above total residence times of
for example below 4.0 hours are sufficient. Residence
times as low as 0.05 hours (at 65C or higher) have
been found suitable, residence times of from 0.25 to
2.0 hours (at lower temperatures) are generally suita-
ble. If step A in the preferred embodiment is carried
out in two or more stages (as is preferred) the
residence time in the last stage of step A is prefer-
ably below 1.0 hour.
The reaction product mixture obtained in step A
may be reacted, without additional treatment, in step
C or the unreacted epichlorohydrin may be removed
therefrom before it is reacted in step C. In the
preferred embodiment of the invention, in which an
oY.ygen-containing organic solvent and water is added
in step A, the aqueous phase and the organic phase
are separated (by settling and decantation, or by
~1~8433
16
centrifugation) (step B) and the organic phase is
further reacted in step C. The settling is very fast,
and settling times can be as low as one minute in a
continuous process; in a batch process a longer settling
time can be accepted; settling is generally completed
within 0.5 hours. It is not necessary to heat or cool
the reaction product before or during separation. The
aqeuous phase thus obtained is a substantially neutral
aqueous solution comprising ionizable halide; the small
amounts of unreacted epihalohydrin and oxygen-containing
organic solvent which it also contains can easily be
removed by conventional techniques such as stripping
and may be used, as appropriate, in reaction step A or
reaction step C. The stripped effluent may be dis-
carded.
In the preferred embodiment the organic phaseobtained in step B is reacted in step C, in one or more
stages, preferably two stages, with an aqueous solution,
such as a from 20 to 50 %w aqueous solution, of an
alkali-metal hydroxide, preferably sodium hydroxide.
In the first stage of step C the amount of alkali-
metal hydroxide added, together with the amount of
ionizable hydroxide, if any, added in step A, is less
than 1.0 mole, preferably from 0.85 to 0.99 moles,
for each phenolic equivalent of polyhydric phenol.
added in step A. The components of the aqueous
solution may be added separately to the organic phase
1118433
17
and may be at least partly provided by recycling the
second and any subsequent aqueous phases obtained in
step C. The total residence time needed for step C is
below 2.0 hours with the residence time for the first
stage of step C being preferably from 0.16 to 1.0 hours.
The reaction temperature for the first stage of step C
is preferably above 25C, more preferably from 35 to
65C. The unreacted epihalohydrin and oxygen-containing
volatile organic solvent recovered from the aqueous
phase obtained in step B may be added to this first
stage of step C.
The reaction product obtained in the first stage
of step C readily forms, upon settling, an organic phase
and an aqueous phase which may easily be separated in
the manner described above for step B.
The aqueous phase thus separated, which is a
slightly alkaline aqueous solution comprising alkali-
metal halide, a small amount of alkali-metal hydroxide
and some phenolic compounds, for example phenolic
chlorohydrin ethers, phenolic glycidyl ethers, and
polyhydric phenols, is then recycled to step A. The
aqueous phase may first be neutralized, especially if,
as in the case of a batch process, it is stored before
being added to step A. The aqueous phase may be re-
cycled to any stage of step A and in the case of amulti-stage step A may be recycled to the first or a
subsequent stage thereof, in the latter case the
1~8433
.
18
catalytic effect of the components of this aqueous
phase may not be significant.
The organic phase obtained after the first stage
of step C is then reacted with further amounts of an
aqueous solution, such as a from 20 to 50 %w aqueous
solution, of an alkali-metal hydroxide, preferably
sodium hydroxide, wherein the amount thereof is such
that the total amount of alkali-metal hydroxide added
in step C, together with the amount of ionizable
hydroxide, if any, added in step A, is at least 1.0
moles, preferably from 1.05 to 1.5 moles, for each
phenolic equivalent of polyhydric phenol used in step
A. Suitably step C comprises only two stages and
preferably the residence time for the second stage
thereof is 0.016 to 0.4 hours and preferably the
reaction temperature is from 25 to 65C.
After the second and subsequent stages, if any,
of step C, the reaction product readily forms, upon
settling, an organic phase and an aqueous phase
which may be separated in the manner described above
for step B.
The aqueous phase thus separated which is an
alkaline aqueous solution comprising alkali-metal
hydroxide and small amounts of alkali-metal chloride,
in one preferred embodiment of the invention, is
recycled to step A or to one of the stages thereof,
preferably to the first stage thereof, and therefore
~1~8433
19
provides, at least in park, the water and condensation
catalyst required in step A. In this preferred
embodiment of the invention, the aqueous phase may also
be recycled to the first stage of step C or to a first
stage of a further step C and therefore provides, at
least in part, the aqueous solution of alkali-metal
hydroxide required.
The organic phase obtained after the last stage
of step C is then worked up to recover the polyglycidyl
ether therefrom. The manner or working up is not
critical and usually comprises one or more washing
steps and the removal of the unreacted epihalohydrin,
oxygen-containing organic solvent and water therefrom.
The recovered epihalohydrin, oxygen-containing organic
solvent, water and washwater may be recycled, where
appropriate to one or both of steps A and C or to one
or both of further steps A and C. The recovered poly-
glycidyl ether may be further treated, if desired,
with small amounts of alkali-metal hydroxide in
solvents, such as hydrocarbon solventse.g. toluene.
This preferred embodiment will now be illustrated
by reference to the accompanying drawings in which
Figures 1 to 4 are schematic diagrams of this
preferred embodiment.
In Figure 1, the feedstock stream 1 comprising
a polyhydric phenol, epihalohydrin, oxygen-containing
volatile organic solvent and water, together with the
~8433
aqueous phase recycle stream 13, are continuously fed
to reactor Al. Suitably the feedstock stream 1 is pre-
heated to the desired reaction temperature by means
of heaters, not shown. The reaction product stream 2
is continuously withdraun and fed to reactor A2,
together with the aqueous phase recycle stream 9. The
reaction product stream 3 is continuously withdrawn
and fed to separator B and the lower aqueous phase is
continuously withdrawn as stream 5. The upper organic
phase is also continuously withdrawn, as stream 4, and
fed, together with an aqueous solution of alkali-metal
hydroxide, stream 6, to reactor Cl, after which the
reaction product stream 7 is continuously withdrawn
and fed to separator Sl. The lower aqueous phase is
continuously withdrawn, as stream 9, and fed to
reactor A2. The upper organic phase is also con-
tinuously withdrawn, as stream 8, and fed, together
with an aqueous solution of alkali-metal hydroxide,
stream 10, to reactor C2 after which the reaction
product stream 11 is continuously withdrawn and fed
to separator S2. The lower aqueous phase is con-
tinuously withdrawn, as stream 13, and recycled
to reactor Al. The upper organic phase is also
continuously withdrawn, as stream 12, and the poly-
Klycidyl ether recovered therefrom.
In Figure 2, the scheme is substantially thesame as for figure 1 with the differences that the
8433
21
lower aqueous phase which is continuously withdrawn
as stream 13 is fed to reactor C1, and that an
aqueous solution of alkali-metal hydroxide, stream 14,
is continuously fed to reactor A1.
In Figure 3, the scheme is substantially the
same as for figure 1 with the difference that the
lower aqueous phase which is continuously withdrawn
as stream 9 is fed to the reactor A1. Moreover A1 is
the single reactor in step A and the reaction product
stream 2 is fed directly to separator B.
In Figure 4, the scheme is substantially
the same as for figure 3 with the difference that the
lower aqueous phase which is continuously withdrawn
as stream 13 is fed to reactor C1.
Other embodiments of the invention are given
below in a generalized form. The product of step A,
or the organic phase obtained in step B, is reacted
in step C, in one or more stages, with an aqueous
~olution, such as a from 20 to 50 %w aqueous solution,
of an alkali-metal hydroxide, preferably sodium
hydroxide. The amount of alkali-metal hydroxide added,
together with the amount of ionizable hydroxide, if
any, added in step A, is more than 1.0 moles, preferably
from 1.05 to 1.5 moles for each phenolic equivalent of
polyhydric phenol used in step A. If the unreacted
epihalohydrin is removed before step C it may be de-
sirable to add to the reaction product a solvent such
~J ~8~33
as toluene, benzene or methyl isobutyl ketone.
Suitable amounts of such solvents are from 50 to 300 %w
based on the reaction product to be used in step C.
In one embodiment of the present invention step C
is carried out in one stage and the reaction product
allowed to settle upon which an aqueous phase and an
organic phase are formed and the aqueous phase is
separated as described above. The separated aqueous
phase which is an alkaline aqueous solution of alkali-
metal halide and alkali-metal hydroxide is then used,
at least in part, as a condensation catalyst in step
A or one of the stages thereof. In this embodiment the
organic phase obtained is worked up to recover the
polyglycidyl ether therefrom. The manner of working
up is not critical and usually comprises one or more
waæhing steps and the removal of water and, if present,
unreacted epihalohydrin, and solvents therefrom de-
pending upon the particular conditions used. The re-
covered polyglycidyl ether may be further treated with
Bmall amounts of sodium hydroxide in solvents, such as
hydrocarbon solvents e.g. toluene or oxygen-containing
solvents such as ketones e.g. MEK, MIBK.
In another embodiment of the present invention
step C is carried out in at least two stages. The
reaction product is allowed to settle after each
stage, the aqueous phases separated as described above
and the final organic phase worked up as described
~18433
above. Preferably from 1.0 to 1.15 moles and from
0.05 to 0.35 moles of alkali-metal hydroxide (for each
phenolic equivalent of polyhydric phenol added in stage
A) are added in the first stage and subsequent stages
of step G respectively. Suitably each separated
aqueous phase, or a part thereof, is used as a conden-
sation catalyst in step A or a further step A or the
first separated aqueous phase is used as a condensation
catalyst in step A or one of the stages thereof and the
second and any subsequent separated aqueous phases are
used as a source of aqueous alkali-metal hydroxide
solution in step C or one of the stages thereof. If the
first separated aqueous phase is not used as a conden-
sation catalyst then it may be discarded.
The reaction temperature of step C depends upon
the reaction conditions used but is preferably above
25C, more preferably from 35 to 100C. In the pre-
ferred embodiment of the invention, in which an
oxygen-containing organic solvent and water are added
in step A the reaction temperature is suitably below
75C. The total residence time in step C is suitably
below 4.0 hours.
The invention is illustrated by the following
example8. In Examples 1 to 6 and 10 the figures given
are those obtained under steady-state conditions
(approximately 15 hours~. Before these conditions
were achieved artificial streams were used instead of
433
24
the recycle streams. In the other examples the first
batch was made using an artificial stream, which in
subsequent batches was replaced by the appropriate
effluent from a foregoing batch.
Example 1
The process scheme described in ~igure 1 was used.
The reactor Al (2 litres) was continuously fed by
(a) a feedstock stream 1, (1145.6 g/h), preheated to
a temperature of 43C, comprising
g/h
diphenylol propane 119.7
epichlorohydrin 582.8
isopropanol 340.2
water 102.9
and
(b) the recycle stream 13, (57.5 g/h), from separator
S2 comprising
g/h
sodium hydroxide 7
sodium chloride 5
i~opropanol 2
epichlorohydrin 0.5
water 43
This recycle stream also contained about 4 g/l of
non-volatile carbon compounds of which about 10 %w was
aromatic compounds.
Reactor Al was maintained at a temperature of 43C
433
and the residence time was 45 minutes.
The reaction product stream 2 was continuously
withdrawn and fed (1203.1 g/h) to reactor A2 ( 4
litres) together with the recycle stream 9, (198.9 g/h),
from separator S1, comprising
g/h
sodium hydroxide 2
sodium chloride 43
isopropanol 7
epichlorohydrin 2
water 144.9
This recycle stream also contained about 3 g/l of
non-Yolatile carbon compounds of which about 90 %w was `
aromatic compounds.
~eactor A2 was maintained at a temperature of 43C
and the residence time was 5 minutes.
The reaction product stream 3 was continuously
withdrawn and fed (1402 g/h) to separator B in which
two phases formed. The lower aqueous phase was with-
drawn, (295.3 g/h), as stream 5, and worked up as des-
cribed below. The residence time in separator B was 10
minutes.
The upper organic phase was continuously withdrawn,
as stream 4, and fed (1106.7 g/h) to reactor C1, (2.0
litres) together with a 20 ~w aqueous solution of sodium
hydroxide (157.6 g/h~, stream 6.
Reactor C1 was maintained at a temperature of 43C
~118433
26
and the residence time was 30 minutes.
The reaction product stream 7 was continuously
withdrawn and fed (1264.2 g/h) to separator S1 in which
two phases formed. The lower aqueous phase was with-
drawn, as stream 9, and continuously fed (198.9 g/h)
to reactor A2. The residence time in separator S1 was
10 minutes.
The upper organic phase was continuously with-
drawn, as stream 8, and fed (1065.1 g/h~, after cooling,
10 to reactor C2 (0.4 litres) together with a 20 %w
aqueous solution of sodium hydroxide (52.5 g/h).
Reactor C2 was maintained at a temperature of 33C
and the residence time was 5 minutes.
The reaction product stream 11 was continuously
15 withdrawn and fed (117.6 g/h) to separator S2 in
which two phases formed. The lower a~ueous phase was
withdrawn, as stream 13, and continuously fed (57.5 g/h)
to reactor A1. The residence time in separator S2 was
10 minutes.
The upper organic phase was withdrawn (1060.1 g/h),
washed with water to remove any sodium chloride there-
from, flashed and steam-stripped to remove isopropanol,
water and epichlorohydrin therefrom which were recycled
to the various reactors where appropriate. The recovered
liquid diglycidyl ether of diphenylol propane had the
following properties:-
epoxide equivalent weight 175
~118433
27
saponifiable chlorine (%w) 0.03
viscosity (Poise; 25C) 120
The lower aqueous phase, withdrawn as stream 5,
was stripped to remove any isopropanol and unreacted
epichlorohydrin therefrom which was recycled, where
appropriate, to reactor A2. The stripped effluent had
the following composition:-
%w
sodium chloride 23
sodium hydroxide ~ o.o8
carbon-containing compounds 0.10
water balance
Example 2
Example 1 was repeated with the differences that
separation step B was omitted and that a portion of
the lower aqueous stream 9, was bled (295.3 g/h) and
worked up as described for the lower aqueous phase
withdrawn as stream 5. The recovered liquid digly-
cidyl ether of diphenylol propane had the following
properties:-
epoxide equivalent weight 179
saponifiable chlorine (%w) 0.05
viscosity (25C, Poise) 122
and the stripped effluent, derived from the bleed
stream, had the following composition:-
%wsodium chloride 22
sodium hydroxide
~118433
28
carbon-containing compounds 0.3
water balance.
Example 3
The process scheme described in Figure 2 was used,
in which the same temperatures and residence times as
described in Example 1 were used.
The reactor A2 (2 litres) was continuously fed by
(a) a feedstock stream as described in Example 1, and
(b) a 20 %w aqueous solution of alkali-metal hydroxide,
stream 14, (57.5 g/h).
The reaction product stream 2 was continuously
withdrawn and fed (1203.1 g/h) to reactor A2 toge~her
with the recycle stream 9, (200.6 g/h), from separator
Sl, comprising
g/h
sodium hydroxide 2
sodium chloride 43
isopropyl alcohol 7
epichlorohydrin 2
water 146
This recycle stream also contained about 5 g/l
of non-volatile carbon compoundsof which about 90 %w
was aromatic compounds.
The reaction product stream 3 was continuously
withdrawn and fed (1398.7 g/h) to separator B in which
two phases formed. The lower aqueous phase was with-
drawn (294.7 g/h~, as stream 5, and worked up as des-
1118433
29
cribed in Example 1.
The upper organic phase was withdrawn, as stream4, and continuously fed (1104.0 g/h) to reactor C
together with a 20 %w aqueous solution of sodium
hydroxide (100 g/h)~ stream 6, and the recycle stream
13 (57.7 g/h) 7 from separator S2, comprising
g/h
sodium hydroxide 7
sodium chloride 5
volatile carbon compounds 2.5
water 43.2
This recycle stream also contained about 5 g/l
of non-volatile carbon compounds of which about 10 %w
was aromatic compounds.
The reaction product stream 7 was continuously
withdrawn and fed (1266.7 g/h) to separator S1 in which
two phases formed. The lower aqueous stream was with-
drawn, as stream 9, and fed (200.6 g/h~ to reactor A2.
The upper organic phase was withdrawn, as stream
8, and continuously fed (1066.1 g/h), after cooling,
to reactor C2 together with a 20 %w aqueous solution
of sodium hydroxide (52.2 g/h), stream 10.
The reaction product stream 11 was continuously
withdrawn and fed (1118.6 g/h) to separator S2 in which
two phases formed. The lower aqueous phase was with-
drawn, as stream 13, and continuously fed (37.7 g/h) to
reactor C1.
` 111~433
3o
The upper organic phase was withdrawn (1060.9 g/h)
and worked up as described in Example 1. The recovered
liquid diglycidyl ether of diphenylol propane had the
following properties:-
epoxide equivalent weight 181
saponifiable chlorine (%w) 0.08
viscosity (25C, Poise) 125
The lower aqueous phase, withdrawn as stream 5,
after stripping had the following composition
%w
sodium chloride 23
sodium hydroxide 0.08
carbon-containing compounds 0.14
water balance
Example 4
Example 3 was repeated with the differences that
the separation step B was omitted and that a portion
of the lower aqueous stream 9, was bled (294.7 g/h)
and worked up as described for the lower aqueous phase
withdrawn as stream 5. The recovered liquid diglycidyl
ether of diphenylol propane had the following proper-
ties:-
epoxide equivalent weight 180
saponifiable chlorine (%w) 0.07
viscosity t25C, Poise) 120
and the stripped effluent, derived from the bleed
stream, had the following composition:-
11~8433
31
%w
sodium chloride 23
sodium hydroxide
carbon-containing compounds o.6
water balance
Exa`mple 5
Example 1 was repeated using the process scheme
described in Figure 3. Substantially the same results
were obtained.
10` Examp'le 6
Example 2 was repeated using the process scheme
described in Figure 4. The results obtained were
substantially the same as for example 2 except that
the stripped effluent obtained from stream 5 contained
less than 0.05 %w of sodium hydroxide and that the
recovered diglycidyl ether had a viscosity (25C,
Poise) of 133.
Exa`mp'le 7 '
In this example t.he process of the present
invention was carried out in a batch manner.
` P'art' A
A mixture of diphenylol propane (114 g),
epichlorohydrin (555 g), isopropanol (324 g) and
water (80 g) was charged to a reactor (2 litres) and
reacted with an artificial stream - a solution of
sodium hydroxide (9.5 g) and sodium chloride (o.8 g)
in water (40 g) - for 1 hour at 45C. The reaction
~lBD~33
pro,duct was allowed to settle and the lower aqueous
phase (first) was separated.
The remaining organic phase was reacted with a
solution of sodium hydroxide (30 g) in water (121 g)
for 20 minutes at 45C after which the lower aqueous
phase (second) was separated.
The remaining organic phase was reacted with a
solution of sodium hydroxide (10 g~ in water (40 g~
for 5 minutes at 30C and the lower aqueous phase
(third) separated and stored.
The remaining organic phase was worked up as
described above. The liquid diglycidyl ether of di-
phenylol propane had the following properties:-
epoxide equivalent weight 179
saponifiable chlorine (%w) 0.07
viscosity (25C, Poise) 83
The first aqueous phase was stripped to removeisopropanol and unreacted epichlorohydrin therefrom.
The stripped effluent, which was discarded, had the
following composition:-
%w
sodium chloride 22
sodium hydroxide ~ 0.05
carbon-containing compounds 0.1
water balance
The second aqueous phase was also stripped to
remove any isopropanol and unreacted epichlorohydrin
therefrom, to enable analysis for other carbon
compounds. The stripped effluent (198 g), which
was stored, had the following composition:-
%w
sodium chloride 21.5
sodium hydroxide 0.9
carbon-containing compounds 0.4
water balance.
Par't B
10 The above experiment was repeated 5 times, but
with the difference that in each experiment the
aqueous solution of sodium hydroxide and sodium
chloride used in the first step in the above experiment
was replaced by the stored second and third aqueous
effluents of the foregoing experiment; the second
effluent was not stripped anymore, but used as such.
The first aqueous phases (stripped) contained 0.1-0.2
%w of carbon-containing compounds, 22 %w NaCl, and
~0.05 %w NaOH, and the liquid diglycidyl ether had
epoxide equivalent weights 178-182, saponifiable Cl 0.05-
o.o8 %w and viscosity 80-84 Poise (25C).
' Examp'le' 8
Example 7 was repeated with the difference that
the solution of sodium hydroxide and sodium chloride
used in the first step of Part A to initiate the series
was replaced by solutions in water (40 g), of sodium
chloride (10 g~, lithium chloride (8 g~, potassium
1~18433
34
chloride (12 g) and tetramethylammonium chloride (20 g),
and the amount of sodium hydroxide used after the first
separation was increased to 39 g. In Part B this
amount was again reduced to 30 g. The results obtained
were substantially the same as for Example 7; the
resin analysis was the same, and the first aqueous
(stripped) contained also 0.1-0.2 %w carbon-containing
compound.
Example 9
10 Example 7 was repeated, with the difference that
the diphenylol propane was replaced by an equivalent
amount of diphenylol methane (100 g~.
The liquid diglycidyl ether of diphenylol methane
had the following properties:
epoxide equivalent weight 170
saponifiable chlorine (%w) 0.05
viscosity (25C, Poise) 33
phenolic hydroxy (meq/100 g) 1.2
The aqueous phases of Part A were stripped to
remove isopropanol and epichlorohydrin; the stripped
effluents had essentially the same compositions as in
Examples 7.
Example 10
Continuous experiment, as in Example 1, but with
a different process scheme, and higher reaction tem-
peratures (60C~.
The process scheme consisted of 4 reactors in
~118~33
series, each 0.25 l, numbered A, C1, C2, and C3 res-
pectively, with a phase separator (numbered B, S1,S2,
and S3, respectively) after each reactor.
The aqueous phase from separator S3 was recycled
to reactor A (42.6 g/h, contained NaOH 4.7 %w, NaC1
14.7 %w, and 1000-3000 ppm resinous compounds).The
aqueous phases from separators B, S1 and S2 were not
recycled, but stripped to recover isopropanol (4 %w)
and epichlorohydrin (1 %w) and discarded: they con-
tained less than 200 ppm resinous compounds whichdoes not contaminate the stripper in continuous
operation.
The continuous feed for reactor A consisted of the
streams (a), (b) and (c):
15 (a) feedstock stream (1145.6 ~/h~, preheated to 55C,
comprising
g/h
diphenylol propane 119.7
epichlorohydrin 582.8
isopropanol 340.2
water 102.9
(b) 20 %w aqueous solution of sodium hydroxide (106 g/h)
(c) aqueous phase from separator S3 as indicated above.
The temperature of reactor A was kept at 60~C. The
reaction stream was continuously withdrawn from reactor
A, and fed to separator B in which two phases formed.
The lower aqueous phase (149 g/h~ and the upper organic
11~8433
phase were withdrawn, and the latter continuously fed
to reactor Cl, together with a 20 %w aqueous solution
of sodium hydroxide (64 g/h). The temperature in
reactor Cl was kept at 60C.
The reactor stream from Cl was continuously fed
to separator Sl, where two layers formed which were
withdrawn (lower aqueous layer: 101 g/h). The upper
organic phase was continuously fed to reactor C2, to-
gether with a 20 %w aqueous solution of sodium
hydroxide (32 g/h).
The temperature in C2 was kept at 60C.
The reactor stream from C2 was fed to separator
S2; the two layers formed were separated and withdrawn
(lower aqueous layer: 38 g/h) and the upper organic
layer continuously fed to reactor C3, together with a
20 %w aqueous solution of sodium hydroxide (32 g/h).
The temperature in C3 was kept at 60C.
The reactor stream from C3 was fed to separator
S3, the layers formed were withdrawn; the lower
aqueou5 layer was continuously fed to reactor A.
The upper organic layer (1036 g/h) was con-
tinuously washed with water to remove any sodium
chloride and sodium hydroxide therefrom, and then
flashed and steam-stripped to remove isopropanol,
epichlorohydrin and water (this mixture of volatiles
can be recycled to reactor A, with fresh components
to make up for the right feed composition).
11~. B~33
.
The recovered liquid diglycidyl ether of diphenylol propane had the
following properties:
epoxide equivalent weight 183
saponifiable chlorine ~%w) 0.01
phenolic hydroxy (meq./100 g) 1.1
viscosity ~Poise; 25C) 105
Example 11
A mixture of diphenylol propane (109 g), epichlorohydrin (886 g),
isopropanol (346 g) and water (87 g) was charged to a reactor ~2 litres) and
0 reacted with a solution (added over 5 minutes) of sodium chloride (50.6 g) and
sodium hydroxide (1.9 g) in water ~117.5 g) for a total of 20 minutes at 45C.
The reaction product was allowed to settle and the lower aqueous phase ~first)
was separated. The remaining organic phase was reacted with a 19.4% aqueous
solution of sodium hydroxide (204 g) for 15 minutes at 45 after which the lower
aqueous phase ~second) was separated.
The remaining organic phase was reacted with water to remove any
sodium chloride therefrom, flashed and steam-stripped to remove isopropanol,
water and epichlorohydrin therefrom. The product was dissolved in toluene and
treated with a 2.5 %w solution of sodium hydroxide.
The final product had the following properties.
epoxide equivalent weight 178
saponifiable chlorine ~%w) 0.03
viscosity (25C, Poise) 76
The first aqueous phase was stripped to remove isopropanol and un-
reacted epihalohydrin therefrom.
P~
-37-
8433
38
The stripped effluent, which was discarded, had the
following composition:-
%w
sodium chloride 23
sodium hydroxide 0.04
water 77
The second aqueous phase was also stripped to
remove isopropanol and epichlorohydrin therefrom. ~he
stripped effluent (231 g), which was stored, had
the following composition:-
%w
sodium chloride 22
sodium hydroxide 1.0
water 77
15 The above experiment was repeated with the differ-
ence that in the first step the aqueous solution of
sodium chloride and sodium hydroxide was replaced by
the stored stripped effluent obtained from the second
aqueous phase.
Substantially the same results were obtained.
EXample 12
The procedures of example 11 were repeated with
the differences that the first reaction product was
not allowed to settle, but reacted immediately with the
19.4 % w aqueous solution of sodium hydroxide and
that only a part (231 g~ of the subsequently obtained
lower aqueous phase, after stripping, was used in place
~18433
39
of the aqueous solution of sodium chloride and sodium
hydroxide in the repeat experiment. The recovered
diglycidyl ether had substantially the same properties
as that obtained in example 11.
Example 13
The first experiment of example 11 was repeated
with the differences that both of the aqueous phases,
after stripping, were discarded and that the second
organic phase was not worked-up but reacted with a
20.1 %w aqueous solution of sodium hydroxide (58 g)
for 5 minutes at 42C after which the reaction
product was allowed to settle and the aqueous phase
(third) was separated. The organic phase thus ob-
tained was washed and steam-stripped to remove iso-
propanol, water and epichlorohydrin therefrom to
produce a final product having the following properties:-
epoxide equivalent weight 178
saponifiable chlorine (%w) 0.11
viscosity (25C, Poise) 75
The third separated aqueous phase was stripped to
remove -,sopropanol and epihalohydrin therefrom. The
stripped effluent (65 g), which was stored, had the
following composition:-
%w
25 sodium chloride 10
sodium hydroxide ` 8
water 82
~8433
In the repeat experiment the 19.4 %w aqueous
solution of sodium hydroxide reacted with the first
organic phase was partly made-up from the above stored
stripped effluent. The final product has substantially
the same properties as described above.
Example 14
A mixture of diphenylol propane (109 g), epi-
chlorohydrin (886 g) and 1 molé % of tetramethyl-
ammonium chloride (based on diphenylol propane) and
reacted for 2 hours at 100C after which the unreacted
epichlorohydrin was removed by vacuum distillation.
The reaction product was dissolved in methyl isobutyl -~;
ketone to produce a 35 %w solution which was reacted
with a 5 %w aqueous solution of sodium hydroxide
containing 1.01 moles of sodium hydroxide for 1 hour
at 85C after which the reaction product was allowed
to settle and the lower aqueous phase was withdrawn
and discarded.
The remaining organic phase was reacted with a
further 20.1 %w aqueous solution of sodium hydroxide
in an amount corresponding to 0.25 moles of sodium
hydroxide for each mole of diphenylol propane after
which the lower aqueous phase was withdrawn and stored.
The remaining organic phase was washed and steam-
~tripped to remoYe the methyl isohutyl ketone and watertherefrom to produce a finaI product ha~ing the
following properties.-
~118433
41
epoxide equivalent weight 185
saponifiable chlorine (%w) 0.1
viscosity (25c, Poise) 80
The above experiment was repeated with the
5 difference that the 5 %w aqueous solution of sodiumhydroxide reacted with the first organic phase was
partly made-up from the above stored aqueous phase.
The final product had substantially the same properties
as described above.
Example 15
The novolac used in this example had molecular
weight 500-600 and contained 0. 96 phenolic equivalents
per 100g.
Part A. (Initiating the series of experiments) Novolac
15 (0.54 kg), epichlorohydrin ( 2.42 kg)~ isopropanol
(1.42 kg) and water (o.78 kg) were heated to 35 c in a
6 l-reactor with stirrer, and reacted with a solution
of sodium hydroxide ( 52 g) in water ( 52 g) during 20
minutes at 45C.
A solution of sodium hydroxide ( 151 g) in water
(151 g) was added in 4 equal parts at 5 minutes inter-
vals.
~he temperature rose to 50c, and was reduced to 45C
by cooling. After 30 minutes the phases were separated
25 ( settling time 15 minutes), the aqueous phase (first)
was stripped to recover isopropanol and epichlorohydrin
and discarded (NaOH content; 0.1 %w~.
~i~8433
42
The organic phase was cooled to 30C, and reacted
with a solution of sodium hydroxide (52 g2 in water
(208 g) for 5 minutes. The phases were separated
(settling time 15 minutes~, and the aqueous phase
was (second2 stored.
The resin was recovered from the organic phase by
vacuum stripping distillation; the crude resin was
dissolved in methyl ethyl ketone (2 12, and the so-
lution washed twice with a dilute aqueous sodium
dihydro phosphate solution (o.6 l; 0.3 %w NaH2PO4).
Volatiles were distilled off, last traces in
vacuum at 120C.
The resin had the following properties:-
epoxide equivalent weight 186
saponifiable chlorine (%w) 0.15
phenolic hydroxy (meq./100 g) 3.5Par't B (according to the invention2. The experiment
was repeated four times, with the exception that now
aqueous sodium hydroxide in the first step was re-
placed by the s,tored aqueous phase of the foregoingexperiment.
Here also settling timesof 15 minutes were
sufficient, the first aqueous phase was low in
alkalinity, and the resin properties were the same
(within 1% accuracy).
Exampl'e' 16
Example 15 was repeated, with the difference that
11~8433
43
the novolac was replaced by the equivalent amount
of a technical tetraphenylol ethane (520 g; 10 phenolic
equivalents per kg). The resin properties were
(1% accuracy):-
epoxy equivalent weight 172
saponifiable chlorine (%w) 0.05
phenolic hydroxy (meq/100 g) 2
Here also settling times of 15 minutes were
sufficient, and the first aqueous phases of the series
were low in alkalinity.
