Crosslinked resins containing thermally stable sulfonic acid groups

Novel crosslinked resins comprising at least on substituted aryl group having a functional substituent group of the general formula ##STR1## can be prepared via the addition reaction of a crosslinked resin comprising at least one substituted aryl group having a functional substituent group of general formula ##STR2## and an ester of an alkenesulfonic acid of general formula EQU C(H)(R.sup.1).dbd.C(H)-SO.sub.3 R.sup.3 (III), wherein, a is 0 or 1, b is 1 or 2, d is 1 or 2, e is 0 or 1, R.sup.1 represents H or a C.sub.1 -C.sub.4 alkyl group, R.sup.2 is a --CN or a carboxyester group, R.sup.3 is hydrocarbyl group, M is a proton or another cation, and moreover that in general formula (I) b+d+e=3, and in general formula (II) that b+e=2 and if b is 2 each R.sup.2 is a --CN or a carboxyester group, followed by hydrolysis of the addition product into a functional group of general formula (I). Said resins are extremely stable at elevated temperatures in water or aqueous media and show a high catalytic activity.

FIELD OF THE INVENTION 
The present invention relates to crosslinked resins containing thermally 
stable sulfonic acid groups, in particular to thermally stable 
sulfoalkylated polystyrene-divinylbenzene resins, and to their preparation 
and use. 
BACKGROUND OF THE INVENTION 
Sulfonated polystyrene-divinylbenzene (PS/DVB) resins have been 
commercially available for many years and used as cation exchange resin in 
many different applications such as in water treatment, in recovery of 
metals from aqueous solutions, as catalysts, in chromatography etc. 
However, their applicability has been restricted due to their low thermal 
stability in water or water-containing media. Above 150.degree. C. the 
aromatic sulfonic acid groups are increasingly hydrolyzed. 
A class of sulfonated PS/DVB resins less susceptible to thermal degradation 
are the sulfoalkylated PS/DVB resins, which have been disclosed in 
Makromolekulare Chemie, Vol. 184, pp. 1585-1596 (1983). Also disclosed was 
evidence of their thermal stability, established by measuring the cation 
exchange capacity of these resins after heating aqueous suspensions of 
these products in an autoclave at 200.degree. C. Whereas with a 
conventional sulfonated PS/DVB resin, 75% of the sulfonic acid groups had 
disappeared after 48 hours, with the sulfomethylated and sulfoethylated 
resins the loss of sulfonic acid groups was only 30-45% and 20% 
respectively. Although it was reported that problems had been experienced 
with the synthesis of the corresponding sulfopropylated resins, even with 
these resins the loss of sulfonic acid groups was never more than 60% 
under the above mentioned conditions. 
Although these sulfoalkylated resins were found to be more stable at 
elevated temperatures compared with the conventional sulfonated PS/DVB 
resins, there is room for improvement, especially when they are used as 
catalysts in processes which are conducted at high temperatures for long 
periods of time. Under those circumstances catalyst instability, i.e. 
premature loss of sulfonic acid groups, would be unacceptable. 
Surprisingly a novel class of sulfoalkylated resins has now been 
synthesized, having a thermal stability--by which we mean stability of the 
resin in the acid form at elevated temperatures in the presence of water 
or in aqueous media, hereinafter referred to as thermal stability--which 
surpasses that of the sulfoalkylated resins previously described. These 
novel resins are characterized in that the alkyl group carries, in 
addition to the sulfonic acid group, at least one carboxy group. 
SUMMARY OF THE INVENTION 
The present invention provides therefore crosslinked resins comprising at 
least one substituted aryl group having a functional substituent group of 
general formula 
##STR3## 
wherein a is 0 or 1, b is 1 or 2, d is 1 or 2, e is 0 or 1, b+d+e=3, 
R.sup.1 represents H or a C.sub.1 to C.sub.4 alkyl group and M is a proton 
or another cation. 
The invention also provides a process for the preparation of these novel 
thermostable crosslinked resins which comprises reacting 
(a) a crosslinked resin comprising at least one substituted aryl group 
having a functional substituent group of general formula 
##STR4## 
wherein a, b and e have the same meaning as in general formula (I), b+e=2, 
R.sup.2 is a --CN or a carboxyester group, and if b is 2 each R.sup.2 
represents a --CN or a carboxyester group, and 
(b) an ester of an alkenesulfonic acid of general formula 
EQU C(H)(R.sup.1)=C(H)--SO.sub.3 R.sup.3 (III) 
wherein R.sup.1 has the same meaning as in general formula (I) and R.sup.3 
is a hydrocarbyl group, 
with the formation of an addition product of general formula 
##STR5## 
wherein a, b, d, e and R.sup.1 have the same meaning as in general formula 
(I), b+d+e=3, R.sup.2 has the same meaning as in general formula (II) and 
R.sup.3 has the same meaning as in general formula (III). 
followed by hydrolysis of the addition product of general formula (IV) 
(hereinafter referred to as a Michael adduct) into a functional group of 
general formula (I). 
DESCRIPTION OF THE INVENTION 
In the preparation of the crosslinked resins carrying at least one 
functional group of general formula (I) the same crosslinked resins may in 
principle be employed as those employed in the preparation of the 
conventional sulfonated cation exchange resins and which have been 
described in numerous publications, such as: Encyclopedia of Polymer 
Science and Technology, Vol. 7, pp. 693-742. 
The majority of the commercially available synthetic cation exchange resins 
are based on PS/DVB resins having a DVB content in the range of from about 
0.5 to about 30% wt, preferably from about 2.0 to about 20% wt, of the 
PS/DVB resin, and although there is also a strong preference for these 
PS/DVB resins in the practice of the present invention, this should, 
however, not be construed to be a restriction of the invention. The 
primary requirement for these crosslinked resins, in order that they may 
suitably be employed in the preparation of the crosslinked functionalized 
resins of the present invention, is that they should be able to carry a 
halomethyl group, preferably a chloromethyl group. Hence, crosslinked 
resins obtained by polymerization of mixtures of e.g. styrene and 
divinylbenzene in the presence of a minor amount of one or more suitable 
comonomers, e.g. mono ethylenically unsaturated compounds such as acrylic 
or methacrylic acid and/or derivatives thereof, such as the corresponding 
esters, may also be employed. PS/DVB resins are divided into two 
categories, i.e. the gel-type PS/DVB resins, having a DVB content which is 
generally not much higher than 2 to 3% wt, and the macro-porous type of 
PS/DVB resins having a higher DVB content, generally .gtoreq.5% wt. 
The halomethylation is well known, in particular the chloromethylation of 
the above described crosslinked resins. Moreover, some types of 
chloromethylated PS/DVB resins are commercially available, e.g. gel-type 
chloromethylated PS/DVB resins which are also known as Merrifield resins. 
In order to convert the chloromethylated PS/DVB resins into compounds of 
general formula (II), which have an activated CH or CH.sub.2 group 
(hereinafter referred to as active methylene groups), they may be reacted 
with an inorganic cyanide, preferably an alkali- or alkaline earth metal 
cyanide, or with such compounds as diesters of malonic acid, e.g. diethyl 
malonate, esters of cyanoacetic acid, dicyanomethane, esters of acetic 
acid, and acetonitrile, with a preference for diethyl malonate. 
The reaction of chloromethylated PS/DVB resins with an inorganic cyanide 
may conveniently be carried out in the presence of a solvent such as 
dimethylsulfoxide (DSMO) or N,N-dimethylformamide (DMF), as reported by 
Frechet et al, in Journal of Organic Chemistry, Vol. 44, No. 11 (1979), p. 
1776 who also experienced an almost quantitative conversion in a two phase 
system in the presence of a phase transfer catalyst. This publication also 
describes the base-catalyzed reaction of chloromethylated PS/DVB resins 
with malonic acid derivatives under various reaction conditions. From this 
publication it is apparent that the choice of reaction conditions required 
to convert the chloromethylated PS/DVB resins into the corresponding 
activated methylene group-containing compound in high yield, will to a 
large extent be determined by the nature of the reactants, e.g., the 
inorganic cyanide and the malonic acid derivatives. 
The base-catalyzed reaction between an active methylene group-containing 
compound and an ester of vinylsulfonic acid is known from a publication by 
H. Distler in Angewandte Chemie, international edition, Vol. 4 (1965), No. 
4, pp. 300-311. Said publication, however, does not disclose reactions of 
esters of an alkenesulfonic acid with crosslinked resins having at least 
one aryl group carrying a group of general formula (II), but was 
restricted to simple, well defined, soluble compounds the derivatives of 
which are not suitable to be used in the same manner as the products of 
the invention. The type of esters of the alkene-sulfonic acid (hereinafter 
referred to as alkenesulfonate), which may conveniently be used in the 
practice of the present invention, may be selected from the group of alkyl 
and aryl esters with a preference for the aryl type of esters and more in 
particular for the phenyl ester as these are generally more stable under 
the prevailing alkaline reaction conditions. 
Instead of employing the above mentioned alkenesulfonate esters, it is also 
possible to use the corresponding sulfonamides or sulfonylfluorides in the 
preparation of the Michael adducts. However, it will require considerably 
more severe conditions to convert the thus obtained sulfonamide adducts 
into the corresponding sulfonic acid group-containing products. 
The alkenesulfonic acids, of which the corresponding esters of general 
formula (III) may conveniently be employed in the practice of this 
invention, include acids such as vinylsulfonic acid, 1-propene-1-sulfonic 
acid, 1-butene-1-sulfonic acid and 1-pentene-1-sulfonic acid. A preference 
is expressed for the esters of vinylsulfonic acid. 
The base-catalyzed reaction between the alkenesulfonate and the active 
methylene group-containing PS/DVB resin may be carried out under a variety 
of conditions, e.g. suspending the active methylene group-containing resin 
in a solvent which will simultaneously dissolve the base catalyst and the 
alkenesulfonate, or alternatively using a two-phase liquid system with a 
phase transfer catalyst. It was found to be especially beneficial to 
conduct this reaction under phase transfer conditions. It will be 
understood by those skilled in the art that the choice of reaction 
conditions will to a large extent be determined by the nature of the 
reactants, i.e. the type of active methylene groups, the degree of 
crosslinking of the base resin, e.g. the PS/DVB resin, the alkenesulfonate 
and the type of catalyst used. 
With this reaction, which may conveniently be carried out under reflux 
conditions, a molar excess of the alkenesulfonate over the equivalents of 
active hydrogen of the active methylene group proved to be beneficial. The 
composition of the products resulting from the reaction between the 
alkenesulfonate and the active methylene group-carrying PS/DVB resin may 
vary considerable. Primarily the composition will be determined by the 
nature of the active methylene groups, i.e. the number of active hydrogen 
atoms per group and the type of substituent e.g. --CN or --COOR. 
Furthermore, the degree of reaction between the active methylene 
group-carrying resin and the alkenesulfonate will be determining for the 
ultimate composition and may be strongly influenced by the accessibility 
of the active hydrogen atoms. Hence, when employing e.g. a PS/DVB resin 
with a high DVB content it will be more difficult to achieve a double 
substitution, or in some cases even a single substitution, compared to 
conditions where less crosslinked resins are employed e.g. the Merrifield 
resins. Moreover it is feasible under the prevailing alkaline reaction 
conditions that some of the alkenesulfonic acid ester and/or carboxy ester 
groups may be hydrolyzed and thereby introduce an additional variation in 
the ultimate composition of the Michael adduct. 
In order to obtain the functionalized crosslinked resins of the present 
invention, the Michael adducts described above have to be submitted to a 
single- or multistep acid- and/or base-catalyzed hydrolysis reaction and 
when required this may be followed by an acidification step to obtain the 
products of the invention in the acid form. Both the sulfonic acid ester 
groups as well as the carboxy esters may conveniently be converted into 
the corresponding sulfonate and carboxylate groups via a base-catalyzed 
hydrolysis reaction, e.g. hydrolysis in 1N NaOH or under phase transfer 
conditions. For the conversion of the nitrile groups into the 
corresponding carboxy groups, via the intermediate amide groups, an 
acid-catalyzed hydrolysis is generally employed, e.g. at reflux 
temperature under strong acid conditions such as 60% wt sulfuric acid. 
Under these circumstances a quantitative conversion of the nitrile groups 
into the corresponding amide groups may be achieved. However, for a 
complete conversion of the intermediate amide groups into the 
corresponding carboxy groups somewhat more severe reaction conditions may 
be required, e.g. higher temperature, longer reaction times. Alternatively 
an incomplete conversion of the amide group into the carboxy group may be 
remedied by heating the ultimate resin in the acid form, i.e. after having 
conducted the base-catalyzed hydrolysis, in aqueous media. 
When both an acid-catalyzed and a base-catalyzed hydrolysis is required for 
the conversion of the Michael adducts into the crosslinked resins of the 
invention, as is the case with Michael adducts derived from resins having 
an active methylene group of general formula (II) wherein one or more --CN 
groups are present, there is a preference to first apply the 
acid-catalyzed hydrolysis and carry out the base-catalyzed hydrolysis 
thereafter. 
With the crosslinked resins of the invention wherein the sulfoalkyl group 
carries two carboxy groups it is possible, when desired, to submit this 
resin to an acid-catalyzed decarboxylation reaction to obtain the 
corresponding resin wherein the sulfoalkyl group carries only one carboxy 
group.

The invention will further be understood from the following examples 
wherein the reaction was followed by infrared (IR) analysis while product 
analysis data was obtained by way of elemental analysis and potentiometric 
titration. 
EXAMPLE 1 
Experiment 1-Preparation of chloromethylated macroporous PS/DVB Resin. 
20 g of a non-commercial macroporous PS/DVB resin having a DVB content of 
10% wt was suspended in 80 ml of chloromethyl methyl ether and 80 ml of 
chloroform and allowed to swell at room temperature for 60 minutes. 
Subsequently a mixture of 6 ml of stannic tetrachloride and 40 ml of 
chloromethyl methyl ether was added to the suspension, whereupon the 
reaction mixture started to reflux. The reaction mixture was kept at 
reflux temperature for 60 minutes. After cooling, the mixture was poured 
into 400 ml of dioxane/water 1/1 v/v and subsequently the resin was 
isolated by filtration and washed consecutively with 400 ml of each of the 
following solvent blends and solvents: dioxane/water 1/1 v/v; 
dioxane/water/conc.hydrochloric acid 5/4/1, dioxane and methanol. After 
drying at room temperature the resin was further dried over diphosphorous 
pentoxide (P.sub.2 O.sub.5) at subatmospheric pressure (approximately 0.01 
mm Hg) and 80.degree. C. for 20 hours. 
Experiments 2-4-Preparation of cyanomethyl-PS/DVB resin. 
Sodium cyanide (NaCN) was added to a suspension of a chloromethylated 
PS/DVB resin in dry DMF and the mixture was stirred at 80.degree. C. The 
resin was isolated by filtration and washed consecutively with DMF, water 
and methanol, and finally dried over P.sub.2 O.sub.5 at subatmospheric 
pressure (approximately 0.01 mm Hg) and 80.degree. C. 
The amounts of reactants and washing liquids used and the reaction 
conditions are given in Table 1 together with the analytical data of the 
ultimate products. 
TABLE 1 
______________________________________ 
Experiment 2 3 4 
______________________________________ 
ClMe-Ps/DVB resin* A B B 
Meq Cl/g 5.05 4.8 4.8 
ClMe-PS/DVB resin, g 
11.5 20 33 
NaCN, mmol 144 300 460 
DMF, ml 120 200 285 
Temperature, .degree.C. 
80 80 80 
Reaction time, hrs. 
16 16 24 
DMF, ml 250 500 500 
Water, ml 250 500 500 
Methanol, ml 250 500 500 
CyMe-PS/DVB resin** yield g 
11 18 30 
Meq Cl/g 0.17 0.1 0.01 
Meq N/g 4.9 5.1 4.9 
______________________________________ 
*ClMe-PS/DVB resin = chloromethylPS/DVB resin 
A as prepared in experiment 1 
B Merrifield resin based on PS/DVB containing 2% wt DVB 
**CyMePS/DVB resin = cyanomethylPS/DVB resin 
Experiments 5-8-Preparation of the adduct of cyanomethyl-PS/DVB resin and 
phenyl vinylsulfonate. 
Cyanomethyl-PS/DVB resin was suspended in dry THF, whereupon a molar excess 
of phenyl vinylsulfonate was added together with 
1.4.7.10.13.16-hexaoxacyclooctadecane (18-Crown-6) and powdered potassium 
hydroxide (KOH) and the reaction mixture was stirred at reflux 
temperature. Subsequently the resin was isolated by filtration and washed 
with THF, THF/water 1/1 v/v, water and methanol, respectively and finally 
dried over P.sub.2 O.sub.5 at subatmospheric pressure (approximately 0.01 
mm Hg) and 80.degree. C. The amounts of reactants and solvents employed 
and the reaction conditions are given in Table 2 together with the 
analytical data of the ultimate resin. By comparing the N and S contents 
of the different products, it can be seen that with the products of 
examples 7 and 8, on average more than one phenyl vinylsulfonate group had 
reacted onto one cyanomethyl group. 
TABLE 2 
______________________________________ 
Experiment 5 6 7 8 
______________________________________ 
CyMe-PS/DVB resin ex experiment 
2 2 3 4 
Meq N/g 4.9 4.9 5.1 4.9 
CyMe-PS/DVB resin, g 
4.2 3.6 10 15 
PVS*, mmol 43 53 144 210 
THF, ml 200 200 250 375 
KOH, mmol 30 30 72 107 
18-Crown-6, mmol 9.2 8.9 24 36 
Time, hrs. 16 40 36 24 
THF,ml 200 200 400 500 
THF/water, ml 200 200 400 500 
Water, ml 200 200 400 500 
Methanol, ml 200 200 400 500 
Resin yield, g 5.5 4.9 21.2 40 
(Michael adduct) 
Meq N/g 3.7 3.6 2.3 2.0 
Meq S/g 1.3 1.6 3.1 3.1 
______________________________________ 
*PVS = phenyl vinylsulfonate prepared from 2chloroethane-sulfonyl chlorid 
and phenol as described by H. Distler in Angewandte Chemie, Intern., Ed., 
Vol. 4 (1965), No.4, page 301. 
Experiments 9-12-Preparation of (3-sulfo-1-carboxy-propyl)-PS/DVB resin 
and/or [3-sulfo-1-carboxy-1-(sulfoethyl)-propyl]-PS/DVB resins. 
The Michael adducts as prepared in examples 5-8 were suspended in 60% wt 
sulfuric acid (H.sub.2 SO.sub.4) and the suspensions refluxed as indicated 
in Table 3. After isolation by filtration the resins were thoroughly 
washed with water, dried over P.sub.2 O.sub.5 at subatmospheric pressure 
(approximately 0.01 mm Hg) and 80.degree. C. and analyzed. 
Subsequently the acid-hydrolyzed resins were refluxed with aqueous 2N NaOH 
and after filtration washed with water. Subsequently the resins were 
repeatedly stirred with an excess of aqueous 1N HCl to replace the 
Na.sup.+ by H.sup.+ and subsequently washed with water until the washing 
liquid was neutral. Finally, the resins were dried over P.sub.2 O.sub.5 at 
subatmospheric pressure (0.01 mm Hg) and 80.degree. C. 
The amounts of reactants and solvents used and the reaction conditions are 
given in Table 3 together with the analytical data of the resins produced. 
As it has previously been established that in the preparation of the 
Michael adducts according to examples 7 and 8 double substitution had 
occurred next to monosubstitution, the resins containing sulfonic acid 
groups prepared in examples 11 and 12 will contain structures of general 
formula (I) wherein a is 0 and d is 2 in addition to structures of general 
formula (I) wherein a is 0 and d is 1. 
TABLE 3 
______________________________________ 
Experiment 9 10 11 12 
______________________________________ 
Michael adduct ex experiment 
5 6 7 8 
Meq N/g 3.7 3.6 2.3 2.0 
Meq S/g 1.3 1.6 3.1 3.1 
Michael adduct, g 5.3 4.7 15 25 
60% wt H.sub.2 SO.sub.4. ml 
40 40 120 200 
Reflux time, hrs. 40 40 96 120 
Water, 1 1 1 3 5 
Meq N/g 0.8 0.8 1.3 -- 
Meq S/g 1.3 1.5 2.8 -- 
Acid hydr. Michael adduct, g 
2.8 4.6 10 -- 
2N NaOH, ml 40 54 200 400 
Reflux time, hrs. 90 90 54 120 
Water,1 1 1 3 5 
Meq N/g 0.7 0.6 1.0 0.5 
Meq S/g 1.4 1.3 3.1 3.1 
Meq SO.sub.3 H/g 1.1 1.0 2.7 2.6 
______________________________________ 
EXAMPLE 2 
Experiment 13-Preparation of [2,2-bis-(ethylcarboxy)-ethyl]-PS/DVB resin. 
20 g (125 mmol) of diethyl malonate was added to a suspension of 2.25 g (75 
mmol) of sodium hydride (NaH) (80% dispersion in paraffin oil) in 100 ml 
of dry toluene and stirred at room temperature to dissolve the NaH. 
Subsequently 5 g of Merrifield resin containing 5 meq Cl/g and based on a 
PS/DVB resin containing 2% wt DVB was added and the suspension was stirred 
at 80.degree. C. for 90 hours. The resin was isolated by filtration and 
washed with 300 ml of each of the following solvents: tetrahydrofuran 
(THF), ethanol, water and ethanol and finally dried over P.sub.2 O.sub.5 
at subatmospheric pressure (approximately 0.01 mm Hg) and 80.degree. C. 
yielding 7.2 g of "malonate" resin containing 0.13 meq Cl/g. 
Experiment 14-Preparation of adduct of "malonate" resin and phenyl 
vinylsulfonate. 
To a suspension of 4 g of [2,2-bis-(ethylcarboxy)-ethyl]-PS/DVB resin (as 
prepared in experiment 13) in 80 ml of dry THF, which suspension further 
contained 8 g of phenyl vinylsulfonate and 2 g of 18-Crown-6, 1.25 g of 
powdered KOH was added and the mixture stirred at reflux temperature for 
16 hours. After cooling the resin was isolated by filtration and washed 
with 300 ml of each of the following solvents: ethanol, water, acetone and 
ethanol and finally dried over P.sub.2 O.sub.5 at subatmospheric pressure 
(approximately 0.01 mm Hg) at 80.degree. C. to yield 5.9 g of resin. 
Experiment 15-Preparation of (4-sulfo-2,2-biscarboxy-butyl)-PS/DVB resin 
and (4-sulfo-2-carboxy-butyl)-PS/DVB resin. 
4 g of the Michael adduct as prepared in experiment 14 was suspended in a 
mixture of 100 ml H.sub.2 O and 100 ml ortho-dichlorobenzene. 40 g KOH and 
5 g of Adogen 464 (registered trade mark) [methyltrialkyl (C.sub.8 
-C.sub.10)-ammonium chloride] were added to the suspension, whereupon the 
mixture was stirred at 100.degree. C. for 90 hours. The IR spectrum showed 
that the carbonyl stretchband of the ester at 1740 cm.sup.-1, had 
disappeared. The resin was isolated by filtration and washed successively 
with 1 l each of water, aqueous 1N HCl, water, ethanol and water and dried 
over P.sub.2 O.sub.5 at subatmosheric pressure (approximately 0.01 mm Hg) 
and 80.degree. C. The elemental analysis of the resin gave the following 
result: C 50.1%, H 6.5%, S 5.8% 1.8 meq S/g, while potentiometric 
titration showed the presence of two --COOH groups of the malonic acid 
moiety. 
2.2 g of the [4-sulfo-2,2-(biscarboxy)-butyl]-PS/DVB resin was suspended in 
30 ml of aqueous 6N HCl and refluxed for 140 hours. After cooling the 
resin was isolated by filtration and thoroughly washed with 1000 ml of 
water and dried over P.sub.2 O.sub.5 at subatmospheric pressure at 
80.degree. C. Elemental analysis of this product resulted in: C 53.9%, H 
6.7%, S 6.75% 2.1 meq/g. Potentiometric titration confirmed the removal of 
one --COOH group and gave 2.2 meq SO.sub.3 H/g. 
EXAMPLE 3 
Experiments 16-18-Hydrolytic stability of (3-sulfo-1-carboxy-propyl) -and 
(4-sulfo-2-carboxy-butyl)-PS/DVB resins. 
0.1-1 g of resin (in the acid form) was suspended in 50 ml of water which 
was contained in a teflon beaker. Said beaker could be tightly fitted in a 
Hastelloy (registered trade mark) autoclave equipped with a thermowell 
which had been covered with teflon tape. 
The autoclave and the suspension were flushed with argon and the suspension 
heated to 200.degree. C. for a period as indicated in Table 4. After each 
indicated period of time the resin was washed with 1N HCl and water, 
respectively before again being suspended in 50 ml of water and 
continuation of the stability tests. The results are given in Table 4. 
TABLE 4 
______________________________________ 
Time at 
Experiment 
Resin 200.degree. C. hrs. 
SO.sub.3 H meq/g 
______________________________________ 
16 (3-sulfo-1-carboxy- 
0 1.2 
propyl)-PS/DVB ex 
90 1.1 
experiment 10* 250 0.9 
500 0.8 
17 (3-sulfo-1-carboxy- 
0 2.9 
propyl)-PS/DVB ex 
300 2.6 
experiment 11* 430 2.2 
18 (4-sulfo-2-carboxy- 
0 2.0 
butyl)-PS/DVB ex 
100 1.9 
experiment 15 200 1.8 
______________________________________ 
*(3-sulfo-1-carboxy-propyl)-PS/DVB resins ex experiments 10 and 11 were 
heated as aqueous suspensions at 200.degree. C. for 46 and 90 hours 
respectively and after cooling washed with 1N HCl to convert the amide 
group into the corresponding carboxy groups, prior to being used for 
assessment of thermostability. 
EXAMPLE 4 
Experiments 19-22-Catalytic activity of (3-sulfo-1-carboxy-propyl)- and 
(4-sulfo-2-carboxy-butyl)-PS/DVB resins. 
The catalytic activities of the different resins were determined employing 
the acid-catalyzed hydrolysis of sucrose i.e. 
##STR6## 
as a convenient test reaction. 
An amount of resin corresponding with approximately 0.3 meq of --SO.sub.3 H 
groups was added to a 10 ml bottle containing 3 ml of a 10% (wt) solution 
of sucrose in distilled water, whereupon the bottom was closed with a 
screw cap. The bottle was placed in a Tamson Precision shaking thermostat 
at 50.degree. C. After a predetermined time the reaction was quenched by 
cooling and the catalyst removed by centrifugation. The optical rotation 
of the supernatant phase was measured with a Perkin Elmer 241 polarimeter 
using the 5890 .ANG. filter. The conversion x was calculated from 
EQU x.sub.t =(.alpha..sub.o -.alpha..sub.t)/(.alpha..sub.o 
-.alpha..sub..infin.) 
wherein .alpha..sub..infin. =-20 .alpha..sub.o /66.5 
From the conversions x.sub.t the observed first-order rate constant, k, was 
calculated according to 
EQU k=(1/t).multidot.ln(1-x.sub.t) 
and the catalytic activity, A, according to A=k.multidot.V/W wherein W is 
the weight of resin (in g) used in the volume V (in 1) of the solution. 
The resins employed in these experiments together with their catalytic 
activities are given in Table 5. 
TABLE 5 
______________________________________ 
Resin source 
Experiment No. 
SO.sub.3 H, meq/g 
A, s.sup.-1 .multidot. g.sup.-1 .multidot. 
______________________________________ 
l 
Experiments 
19 9 1.1 1.2 .times. 10.sup.-6 
20 15 2.2 3.4 .times. 10.sup.-6 
21 11 2.7 4.5 .times. 10.sup.-6 
22 11* 2.2 4.4 .times. 10.sup.-6 
Comparative 
Experiments 
A Amberlite.sup.(1) 
4.3 3.6 .times. 10.sup.-6 
IR 120 H.sup.(2) 
B Amberlite.sup.(1) ** 
1.6 1.6 .times. 10.sup.-6 
IR 120 H.sup.(2) 
______________________________________ 
.sup.(1) registered trade mark 
.sup.(2) Amberlite 120 H is a commercially available ringsulfonated PS/DV 
resin 
*Resin as in experiment 21, but after heating for 90 hours followed by an 
additional 430 hours in aqueous suspension at 200.degree. C. with washing 
with acid and water, respectively after each of the stated periods. 
**Same resin as in comparative experiment A but aged in aqueous suspensio 
at 200.degree. C. for 100 hours, and subsequently washed with acid and 
water, respectively prior to being used as catalyst. 
From the experimental data as given in Examples 3 and 4, it can be seen 
that these novel ion exchange resins are extremely stable at elevated 
temperatures in water and moreover that they possess a high catalytic 
activity making them potentially suitable for a wide range of 
applications.