Epoxy compounds from chlorohydrin ethers of polyphenols

Process for the preparation of compound of the formula: ##STR1## wherein R.sub.c represents a residue comprising one or more additional groups of the formula: ##STR2## by heating a compound of the formula (A) ##STR3## at a temperature in the range of from 120 to 220.degree. C. in the presence of hydrogen halide addition salt of tertiary amine; PA1 process for the preparation of epoxy compounds starting from the reaction of a polyphenol compound and glycidol; and PA1 epoxy resins obtained by this process showing a significantly lower content of intermingled clorine and being substantially free of usual build-up products.

The invention is relating to a process for the manufacture of epoxy 
compounds. More in particular the invention is relating to a process for 
the manufacture of epoxy compounds without the involvement of halogen and 
in particular chlorine gas. 
BACKGROUND OF THE INVENTION 
Epoxy compounds, which are manufactured in a great variety on large 
industrial scales throughout the world, are used for an extensive scale of 
end applications, such as the manufacturing of shaped articles, including 
embedded small electronic components such as semi-conductors or chips and 
the prepregs for the subsequent manufacture of printed circuits for the 
electronic industry, coatings including the organic solvent based coatings 
as well as the more modern aqueous epoxy resin dispersion coatings, and in 
particular can and drum coatings, composites and laminates showing great 
flexibility, and the like. 
Said starting epoxy compounds were manufactured up to now by means of the 
starting reagent epihalohydrin and in particular epichlorohydrin, which in 
its turn was manufactured via allylchloride, prepared from propene and 
gaseous chlorine. 
It will be appreciated that on the one hand, there has been developed in 
the last decade and in particular in the last five years, an increasing 
pressure from national or regional governmental regulations and 
requirements to chemical process industry, in order to drastically reduce 
possible chlorine emissions or even to avoid the use of chlorine 
completely, and on the other hand, in the current manufacturing processes 
for chlorination of propene in the gaseous phase there is still a need to 
improve the relatively low yield and to diminish the high fouling 
tendency. 
Moreover, during the reaction of epihalohydrin with phenolic compounds to 
form epoxy resin it is not possible to avoid completely that halogen, 
originating from the epihalohydrin, is intermingled in a resin as a 
product in the form that the halogen atom is chemically bound to the epoxy 
resin itself. As one of the important applications of the epoxy resin is 
encapsulation of micro electronic material, it will be appreciated that 
this intermingled halogen liberates as an acid by moisture, during use of 
the final article for a long period of time and this acid leads to 
corrosion of a metal material. 
Therefore one object of the present invention is formed by a process, 
meeting the requirements of the present environmental legislation and that 
one presumably enforced in the near future, and starting from cheap and 
generally available basic chemicals. 
One of the alternative manufacturing routes for epoxy resins, proposed in 
the past was that according the following simplified reaction scheme: 
##STR4## 
transesterification with e.g. alkylene carbonate (C.sub.1 -C.sub.4 alkyl), 
cycloalkylene carbonate, arylalkylene carbonate or dialkylene carbonate 
(C.sub.1 -C.sub.4 alkyl) and preferably propylene 
carbonate+alkyleneglycol, cycloalkylene glycol or arylalkylene glycol, and 
preferably propylene glycol, wherein R.sub.1 represents a residue 
comprising one or more additional phenol groups, wherein R.sub.2 
represents a residue comprising one or more additional groups of the 
formula: 
##STR5## 
wherein R.sub.3 represents a residue comprising one or more additional 
groups of the formula: 
##STR6## 
and wherein R.sub.4 represents a residue comprising one or more additional 
groups 
##STR7## 
Although it was already known from e.g. Japanese patent application Sho 
61-33180 A, to produce epoxy compounds by decarboxylating a carbonate 
compound, using as catalyst a combination of an alkali metal halide and of 
a dihydrogenphosphate of an alkali metal while earlier proposed similar 
processes were known from e.g. JP-Sho-57-77682 A and U.S. Pat. No. 
2,856,413, said route could not be used for economical manufacture of 
epoxy compounds up to now. 
In particular from JP-Sho-61-33180 it will be appreciated that the finally 
obtained mono-epoxy compounds had such a simple molecular structure, that 
they could be recovered from the initially crude reaction mixture by 
distillation. 
However such a distillation has appeared to be not possible for the 
commercial standard difunctional and multifunctional epoxy compounds aimed 
at. 
Therefore there was still a strong need for improvement of this proposed 
route to enable industrial scale manufacture at all.

DETAILED DESCRIPTION OF THE INVENTION 
As a result of extensive research and experimentation it has now been 
surprisingly found, that compounds of the formula 
##STR8## 
wherein R.sub.a represents a residue, comprising one or more additional 
groups of the formula VII and wherein R.sub.b represents a residue 
comprising one or more additional groups of the formula 
##STR9## 
can be very efficiently converted into compounds of the formula 
##STR10## 
and CO.sub.2 or SO.sub.2 respectively wherein R.sub.c represents a residue 
comprising one or more additional groups of the formula: 
##STR11## 
by heating at a temperature in the range of from 120 to 220.degree. C. and 
preferably from 140 to 200.degree. C. in the presence of a hydrogen halide 
addition salt of a tertiary amine N(R.sub.1 R.sub.2 R.sub.3) as catalyst 
wherein each of the symbols R.sub.1, R.sub.2 and R.sub.3 may independently 
represent an alkyl group of from 1 to 10 carbon atoms and preferably from 
1 to 5 carbon atoms, an aryl group and preferably a phenyl group, an 
aralkyl group having from 1 to 5 carbon atoms in its alkyl group and 
preferably benzyl or phenyl ethyl, a cycloalkyl group having from 5 to 10 
carbon atoms or an alkylcycloalkyl having from 1 to 6 carbon atoms in its 
alkyl group. 
The hydrogen halide to be used for the addition to the amine for formation 
of the catalyst can be selected from hydrogen chloride, hydrogen bromide 
or hydrogen iodide, but preferably hydrogen chloride is used. 
Preferably tertiary amine addition salts derived from HCl and trialkylamine 
such as trimethylamine, triethylamine, tri-n-propylamine, 
triisopropylamine, tri(n-butyl)amine or tri(isobutyl)amine, and more 
preferably salts derived from HCl and triethylamine or triethylamine are 
used as catalysts. 
The period of heating the compound A or B at the hereinbefore specified 
temperature will normally be in the range from 0.5 to 2 hours and 
preferably from 0.5 to 1 hour. 
It will be appreciated that the product obtained according to this process 
step, can indeed be quantitatively converted into the corresponding epoxy 
compound 
##STR12## 
by a known process step, using a temperature in the range of from 10 to 
120.degree. C. and preferably from 40 to 70.degree. C., in a polar solvent 
and preferably a ketone such as methyl isobutyl keton (MIBK) or toluene 
and using an alkali compound, such as NaOH, providing epoxy resins with an 
epoxy group content (EGC) of at least 5000 mmol/kg. It will be appreciated 
that the significantly improved process step of the present invention has 
formed a bottleneck in the hereinbefore depicted complete reaction scheme 
for some time, making the alternative route much less attractive. 
It will be appreciated that not only relatively simple compounds, such as 
##STR13## 
can be used as starting material of formula I in the above depicted scheme 
but also polymeric compounds, containing a greater number of phenolic 
groups which may partially or completely be converted into the groups of 
formula (VIII). 
I.e. the simple standard epoxy compound of formula 
##STR14## 
can be prepared according to the process of the present invention, but 
also a multifunctional epoxy compound, having a much more complicated 
structure can be prepared. 
For example in this respect, a great variety of phenolformaldehyde resins 
can be used as starting material I (novolac resins). 
It was known for a long time to carry out the industrial scale manufacture 
of compound I starting from a ketone and phenol, providing cheap products. 
An important representative of compound I, having a rather simple structure 
is DPP(diphenylolpropane). 
Also the reagent II (glycidol) can be regarded as a relative cheap product 
prepared from propene. 
The process step from compounds (B) to compounds (C) of the present 
invention has been surprisingly found to be not possible at all when using 
as catalyst only hydrogen halide either as a gas or as an aqueous 
solution. 
It will be appreciated that the invention is also relating to a complete 
integrated manufacturing process for the final epoxy resins comprising the 
hereinbefore specified improved process step and starting from a 
polyphenol compound (I), such as DPP for standard commercial epoxy resins, 
and glycidol (II). 
Accordingly the invention also relates to a process for the manufacture of 
epoxy compounds comprising the steps of 
(a) reaction of a compound 
##STR15## 
wherein R.sub.1 represents a residue comprising one or more additional 
phenol groups, with a compound 
##STR16## 
in the presence of a polar compound, such as a ketone or a mixture of 
ketone with an alkanol having from 1 to 6 carbons, and in the presence of 
an alkali compound such as NaOH, at a temperature of from 30 to 
110.degree. C., and preferably from 60 to 100.degree. C. to form a 
compound of the formula: 
##STR17## 
wherein R.sub.2 represents a residue comprising one or more additional 
groups of the formula 
##STR18## 
b) conversion of the compound of formula III obtained in step (a), into a 
compound of the formula: 
##STR19## 
wherein R.sub.a represents a residue, comprising one or more additional 
groups of the formula: 
##STR20## 
and wherein R.sub.b represents a group a residue comprising one or more 
additional groups of the formula 
##STR21## 
by transesterification with an alkylene carbonate or alkylene sulfite, 
having 1 to 4 carbon atoms alkylene group, a cycloalkylene carbonate or 
cycloalkylene sulfite, arylalkylene carbonate or aralkylene sulphite, or 
dialkylene carbonate or dialkylene sulphite by heating to a temperature in 
the range of from 90 to 160.degree. C. in the presence of an alkali 
compound such as aqueous NaOH solution. 
c) conversion of said compound of formula A or B into a compound of the 
formula 
##STR22## 
and CO.sub.2 or SO.sub.2 respectively, wherein R.sub.c represents a 
residue comprising one or more additional groups of the formula: 
##STR23## 
by heating at a temperature in the range of from 120 to 220.degree. C. and 
preferably from 140 to 200.degree. C. in the presence of a hydrogen halide 
addition salt of a tertiary amine N(R.sub.1 R.sub.2 R.sub.3) as catalyst 
wherein each of the symbols R.sub.1, R.sub.2 and R.sub.3 may independently 
represent an alkyl group of from 1 to 10 carbon atoms and preferably from 
1 to 5 carbon atoms, an aryl group and preferably a phenyl group, an 
aralkyl group having from 1 to 5 carbon atoms in its alkyl group and 
preferably benzyl or phenyl ethyl, a cycloalkyl group having from 5 to 10 
carbon atoms or an alkylcycloalkyl having from 1 to 6 carbon atoms in its 
alkyl group. 
(d) conversion of the compound of formula C into an epoxy compound of 
formula 
##STR24## 
wherein R.sub.4 represents a residue comprising one or more additional 
groups 
##STR25## 
at a temperature in the range of from 10 to 120.degree. C., in a polar 
solvent and using an alkali compound. 
Preferably the reaction step (d) is carried out in a ketone such as methyl 
isobutyl ketone (MIBK) or toluene and using NaOH as alkali. More 
preferably an aqueous NaOH solution is used of 40 to 70 wt %. 
Another aspect of the present invention is formed by the final epoxy resins 
which are obtainable by the complete manufacturing process as specified 
hereinbefore and which do contain significantly less intermingled halogen, 
and in particular chlorine, (at most 1800 ppm) and substantially no 
build-up products (compounds) which are normally present in conventionally 
produced epoxy resins produced from a bisphenol and epihalohydrin of the 
formula 
##STR26## 
wherein R.sup.6 and R.sup.7 may represent lower alkyl, and preferably 
methyl, or hydrogen and wherein n=1, n=2 etc. 
Said epoxy resins are characterized by HPLC analysis. The chromatogram 
clearly shows the absence of the so-called build-up products (n=1, n=2, 
etc.), which are normally present in conventional epoxy resins prepared 
from e.g. bisphenol A and epichlorohydrin, related to peaks at 60.7 and 
76.8, whereas some extra peaks emerge in the chromatogram as can be 
derived from the chromatograms in FIGS. 1 and 2, which were performed 
under the conditions as described in Example X. 
The invention is further illustrated by the following examples and 
comparative examples, however, without restricting its scope to these 
specific embodiments. 
Preparation of the di-.alpha.-glycol ether of DPP 
In a 100 ml three-necked round-bottom flask equipped with a reflux 
condenser and an thermocouple, 22.84 gram (0.100 mmol) diphenylolpropane 
(DPP or bisphenol A) and 15,54 gram glycidol (0.210 mol) is dissolved in 
15.05 gram (0.150 gram (0.150 mol) methyl-isobutylketone (MIBK) and 15.04 
(0.25 mol) isopropylalcohol (IPA). At 80.degree. C., 6 mol % of an aqueous 
NaOH solution (50 wt %) was added at once. The mixture was maintained at 
80.degree. C. for 6 hours. Then, the solvent was removed in vacuo. The 
di-.alpha.-glycol ether of DPP is obtained as a white solid material (33.9 
gram, 89.5%). 
The procedure of this preparation was repeated with variations as depicted 
in the table: 
__________________________________________________________________________ 
Reaction conditions and molar ratio's of reaction products 
glycidol/DPP 
solvent 
temp. 
catalyst 
di.alpha.gc 
1,2-1,3 
1,2-OH 
molar ratio (mol %) (.degree. C.) (mol %) (mol %) (mol %) (mol %) 
build-up 
__________________________________________________________________________ 
1 2.2 MIKB 300 
90 NaOH 85.7 
4.9 0.0 9.1 
2 
2 2.1 MIKB 300 90 NaOH 87.9 4.6 2.6 4.9 
2 
3 2.1 MIKB 300 70 NaOH 89.6 3.9 2.5 4.0 
6 
4 2.1 MIKB 300 90 NaOH 88.2 4.7 1.9 5.2 
2 
5 2.1 MIKB 150 80 NaOH 89.5 4.1 1.7 4.7 
IPA 250 6 
6 2.1 MIKB 270 70 NaOH 88.0 3.7 2.3 6.1 
IPA 45 6 
7 2.1 MIKB 180 70 NaOH 87.0 3.8 4.4 4.8 
IPA 35 6 
__________________________________________________________________________ 
If the reaction is performed in pure MIBK (without IPA as a co-solvent), 
the di-.alpha.-glycol ether of DPP crystalizes after cooling down. 
Preparation of the bis-cyclic carbonate ester of DPP 
A 100 ml round-bottom flask is charged with 20.0 gram of the 
di-.alpha.-glycol ether of DPP (89% pure, 47.3 mmol) and 28.58 gram 
(0.280)propylene carbonate (PC). The mixture is heated at 100.degree. C. 
and 2 mol % of an aqueous NaOH solution (50 wt %) is added. After 1 hour, 
a vacuum is applied to remove the formed propanediol and excess propylene 
carbonate (final conditions 160.degree. C., 20 mbar). The yield of the 
crystalline material is 22.4 gram. 
Preparation of the bis-chlorohydrin ether of DPP 
EXAMPLE 1 
A 100 ml three-necked round-bottom flask is charged with 21.40 (0.05 mol) 
of the biscycliccarbonate ester of DPP and with 13.75 gram (0.1 mol) of 
the HCl salt of triethylamine. The mixture is heated and a vacuum of 300 
mbars is applied. At 140.degree. C., triethylamine is distilled off and 
the temperature is raised in 15 minutes to 180.degree. C. and then to 
200.degree. C. The mixture is held at 200.degree. C. for 10 minutes. The 
total reaction time has been 30 minutes. The conversion to the 
bis-chlorohydrin ether of DPP is 92% (selectivity more than 95%). Side 
products are ketones (about 1%) and epoxides (about 2%). 
EXAMPLE II 
The same procedure as in example I is used, but the distillation is 
continued for 45 minutes at a lower pressure (100 mbar). The conversion is 
100%, the selectivity to the bis-chlorohydrin ether of DPP is more than 
96% (same side products). 
EXAMPLE III 
A 100 ml three-necked round-bottom flask is charged with 11.71 (25 mmol) of 
the bis-cyclic sulphite ester of DPP and with 6.88 gram (50 mmol) of the 
HCl salt of triethylamine (Net3.HCl). The mixture is heated and a vacuum 
of 300 mbars is applied. At 140.degree. C., triethylamine is distilled off 
and the temperature is raised in 15 minutes to 180.degree. C. and then to 
200.degree. C. The mixture is held at 200.degree. C. for 20 minutes. The 
total reaction time has been 40 minutes. The conversion to the 
bis-chlorohydrin ether of DPP is 95% (selectivity more than 95%). Side 
products are epoxides (about 2%). 
EXAMPLE IV 
The same procedure as in example I, but with the tri-methylamine HCl salt. 
The total reaction time has been 30 minutes. The conversion to the 
bis-chlorohydrin ether of DPP is 94% (selectivity more than 95%). Side 
products are ketones (about 1%) and epoxides (about 2%). 
EXAMPLE V 
The same procedure as in example II, but with the tri-propylamine HCl salt 
The conversion to the bis-chlorohydrin ether of DPP is 90% (selectivity 
more than 95%). Side products are ketones (about 1.5%) and epoxides (about 
2.5%). 
COMATIVE EXAMPLE I 
A 100 ml three-necked round-bottom flask is charged with 21.40 (0.05 mol) 
of the bis-carbonate ester. At 100.degree. C. a continuous stream of HCl 
gas is passed through the flask for 4 hours. The conversion of the 
bis-carbonate ester is less than 5%. 
COMATIVE EXAMPLE II 
A 100 ml three-necked round-bottom flask is charged with 10.7 (0.025 mol) 
of the bis-carbonate ester dissolved in 40 ml toluene, and 40 ml of an 
aqueous HCl solution is added. The mixture is stirred at 50.degree. C., 2 
hours. The conversion of the bis-carbonate ester is less than 5%. 
The reaction was also attempted at other temperature (-10.degree. C., 
0.degree. C., 20.degree. C. and reflux) with similar results. 
Preparation of the bis-bromohydrin ether of DPP 
EXAMPLE VI 
The same procedure as in Example II, but the HBr salt of tri-ethylamine is 
used (NEt3HBr). The product in this case is the bromohydrin ether of DPP. 
Conversion is 100%, selectivity over 95%. Side products are epoxides, no 
ketone could be observed. 
EXAMPLE VII 
The same procedure as in Example III, but with Net.sub.3 HBr. The 
conversion is almost 100%, the selectivity is over 95%. 
EXAMPLE VIII 
The same procedure as in Example VI, but with the tri-methylamine HBr salt 
The total reaction time has been 30 minutes. The conversion to the 
bis-bromohydrin ether of DPP is 96% (selectivity more than 95%). Side 
products are (among others) ketones (about 1.5%) and epoxides (about 2%). 
EXAMPLE IX 
The same procedure as in Example I, but with the tri-ethylamine HI salt. 
The total reaction time has been 30 minutes. The conversion to the 
bis-iodohydrin ether of DPP is 89% (selectivity more than 90%). Side 
products are ketones (about 4%) and epoxides (about 4%). 
Preparation of the diglycidyl ether of DPP 
The conversion of the bis-chlorohydrine ether of DPP (3) to an epoxy resin 
can be achieved via a conventional treatment with base in a suitable 
solvent. 
EXAMPLE X 
20.63 Gram (47.9 mmol) of the bis-chlorohydrine ether of DPP is dissolved 
in 64 gram MIBK and heated to 85.degree. C. Then, a solution of 6 gram 
(0.15 mol) NaOH) in 34 gram water is added at once, and the mixture is 
vigorously stirred for 1 hour. After phase separation the MIBK layer is 
washed twice with 20 grams water. The MIBK is evaporated in vacuo to yield 
13.3 gram (83%) of an Epikote 828 type of resin with an epoxy group 
content (EGC) of 5070 mmol/Kg. 
A HPLC analysis of the obtained product provided FIG. 2, using a HP 1090 
liquid chromatograph and dissolving 2.0 g of the resin into 20 g of 
acetonitrile and using anisole as an internal standard. The analysis was 
performed using a NOVOK C18 column, 15 cm.times.3.9 cm, using a flow of 
1 ml/min. and an injection volume of 1 microliter and an initial solvent 
composition consisting of 75% wt of water and 25% wt acetonitrile. A 
solvent gradient was used. 
In 110 minutes the composition changed linear to 6.5% water and 93.5% 
acetonitrile. 
At 115 minutes: 0% water and 100% acetonitrile and at 125 minutes 75% water 
and 25% acetonitrile. 
The analysis was performed at 50.degree. C. with UV detection at 275 nm. 
Under the same conditions a chromatogram was performed from a standard 
EPIKOTE 828 resin (FIG. 1). 
Alternatively, other bases can be used such as metal hydroxides (for 
instance KOH, LiOH, Ca(OH).sub.2, Mg(OH).sub.2), metal carbonates 
(Na.sub.2 CO.sub.3, K.sub.2 CO.sub.3), tertiary amines, NH.sub.4 OH etc. 
Also other solvents can be used, for instance toluene, xylene, MEK, 
CH.sub.2 Cl.sub.2, diethyl ether, etc. 
COMATIVE EXAMPLE III 
Direct conversion of bis-carbonate ester of DPP in the diglycidyl ether of 
DPP. 
Efforts were made to convert the bis-carbonate ester of DPP directly in the 
diglycidyl ether of DPP, using the procedure described in JP-SHO-61-33180. 
The reaction was performed at 250.degree. C. and a vacuum was applied. In 
the beginning of the reaction (first 25 minutes) the lowest pressure 
obtainable was 4 mbar due to CO.sub.2 formation. Hereafter, the vacuum was 
1 mbar. The temperature was raised to 270.degree. C. About 50% of the 
material was distilled. NMR analysis of the distillate showed the presence 
of ketone end-groups instead of epoxy end groups. The residue also 
contained ketone end groups and oligomeric structures, no epoxy end 
groups.