Resins and processes for preparing them

The resin has a polymeric matrix and functional groups of formula I wherein the radicals have the meaning stated in claim 1. The resin is prepared by reacting a corresponding resin having functional groups of formula II with HC(O)R.sup.2 and (R.sup.3).sub.2 SO.sub.3 or (R.sup.3).sub.2 S.sub.2 O.sub.5. The resin is useful for reducing the concentration of alkaline earth or transition metal ions in a solution.

The present invention relates to resins which are useful for reducing the 
concentration of multivalent alkaline earth or transition metal ions in a 
solution containing such ions, to processes for preparing these resins and 
to the use of the resins. Such resins are commonly called ion exchange 
resins. 
The present invention further relates to intermediates which are useful for 
preparing such ion exchange resins and to a process for preparing the 
intermediates. 
It is well known in several areas of technology that cations of the 
alkaline earth metals and transition metals are desired to be removed from 
solutions due to their value or to the detrimental effects they can cause. 
For example, there are situations where these cations are desired to be 
removed from the streams, to the greatest extent possible, prior to the 
a) use of the liquid in chemical or separation processes, 
b) consumption of the liquid or 
c) release of the liquid into the environment. 
It has long been known that it is possible to exchange detrimental ions in 
a stream with more acceptable ions and/or chelate ions to remove them from 
the streams. In this regard there have been many developments made over 
the years in this area of specialized polymeric resins and specialized 
functional groups which can be chemically bound to such resins to provide 
improved systems for the removal of various anions and cations. 
Notwithstanding this activity it remains quite unpredictable which 
functional groups or combinations of functional groups and polymeric 
resins will prove to be suitable for the removal of a particular ion or 
type of ion. 
It remains desirable to provide new water insoluble ion exchange resins 
which are useful for reducing the concentration of alkaline earth or 
transition metal ions in solutions, particularly in aqueous solutions, 
containing such ions. 
Furthermore, it is desirable to provide useful methods for preparing these 
water insoluble ion exchange resins. 
One aspect of the present invention is resin having a polymeric matrix and 
functional groups of formula I 
##STR1## 
wherein: 
R.sup.1 is hydrogen, alkyl of 1 to 12 carbon atoms, cycloalkyl of 3 to 12 
carbon atoms, --(CH.sub.2).sub.n --COOR.sup.7, --(CH.sub.2).sub.p 
--SO.sub.3 R.sup.3, --(CH.sub.2).sub.p --PO.sub.3 (R.sup.7).sub.2 or 
##STR2## 
R.sup.2 independently in each occurence is hydrogen, alkyl of 1 to 12 
carbon atoms, cycloalkyl of 3 to 12 carbon atoms or alkenyl of 2 to 12 
carbon atoms, aryl, aralkyl, aralkenyl, --(CH.sub.2).sub.n --COOR.sup.7, 
--(CH.sub.2).sub.p --SO.sub.3 R.sup.3, --(CH.sub.2).sub.p --PO.sub.3 
(R.sup.7).sub.2 or --CH(SO.sub.3 R.sup.3).sub.2, 
R.sup.3 independently in each occurence is hydrogen or a cation, 
R.sup.4 independently in each occurence is hydrogen, alkyl, cycloalkyl or 
aryl, 
R.sup.5 independently in each occurence is hydrogen, alkyl of 1 to 3 carbon 
atoms, hydroxy or --COOR.sup.7, 
R.sup.6 independently in each occurence is hydrogen, alkyl of 1 to 12 
carbon atoms, cycloalkyl of 3 to 12 carbon atoms, --(CH.sub.2).sub.n 
--COOR.sup.7, --(CH.sub.2).sub.p --SO.sub.3 R3 or --(CH.sub.2).sub.p 
--PO.sub.3 (R.sup.7).sub.2, 
R.sup.7 independently in each occurence is hydrogen, a cation, alkyl of 1 
to 12 carbon atoms or cycloalkyl of 3 to 12 carbon atoms, 
m is from 0 to 12, 
n is from 1 to 12, 
p is from 1 to 6, 
r is from 1 to 6, and 
q is on the average from 0 to 100. 
The above-mentioned resin of the present invention does not have a 
substantial water solubility, has a polymeric matrix which is preferably 
cross-linked and is useful as ion exchange resin. 
Another aspect of the present invention is a process for preparing the 
resin having a polymeric matrix and functional groups of formula I wherein 
a corresponding resin having functional groups of formula II 
##STR3## 
wherein R.sup.1, R.sup.4, R.sup.5, R.sup.6, m, q, and r have the meanings 
given in formula I is reacted with a compound of formula III 
EQU HC(O)R.sup.2 (III) 
wherein R.sup.2 has the meaning given in formula I and a compound of 
formula (R.sup.3).sub.2 SO.sub.3 or (R.sup.3).sub.2 S.sub.2 O.sub.5 
wherein each R.sup.3 independently is hydrogen or a cation. 
In general, each R.sup.3 independently is a cation in formula 
(R.sup.3).sub.2 S.sub.2 O.sub.5. 
Yet another aspect of the present invention is a process for preparing the 
resin having a polymeric matrix and functional groups of formula I by 
reacting a corresponding resin having functional groups of formula V 
##STR4## 
wherein R.sup.1, R.sup.2, R.sup.4, R.sup.5, R.sup.6, m, q, and r have the 
meaning given in formula I with a compound of formula (R.sup.3).sub.2 
SO.sub.3 or (R.sup.3).sub.2 S.sub.2 O.sub.5 
wherein each R.sup.3 independently is hydrogen or a cation. 
In general, each R.sup.3 independently is a cation in formula 
(R.sup.3).sub.2 S.sub.2 O.sub.5. 
By the expression a "corresponding resin" which is used for the starting 
materials in the above-mentioned processes of the present invention is 
meant a resin having different functional groups but the same polymeric 
matrix as the resin to be produced. 
The resins having a polymeric matrix and functional groups of formula V are 
novel. Accordingly, they are another aspect of the present invention. They 
are useful intermediates for producing resins having functional groups of 
formula I. 
Yet another aspect of the present invention is a process for preparing a 
resin having a polymeric matrix and functional groups of formula V by 
reacting a corresponding resin having functional groups of formula II 
##STR5## 
with a compound of formula III 
EQU HC(O)R.sup.2 (III). 
Still another aspect of the present invention is the use of the resin 
having a polymeric matrix and functional groups of formula I wherein 
R.sup.1, R.sup.2, R.sup.4, R.sup.5, R.sup.6, m, r and q have the meanings 
stated above and each R.sup.3 independently is hydrogen or an alkali metal 
ion, preferably sodium, for reducing the concentration of alkaline earth 
or transition metal ions in a solution, preferably an aqueous solution, 
containing such ions. 
Yet another aspect of the present invention is a method of reducing the 
concentration of alkaline earth or transition metal ions in a solution, 
preferably an aqueous solution, containing such ions by containing the 
solution with the resin having a polymeric matrix and functional groups of 
formula I wherein R.sup.1, R.sup.2, R.sup.4, R.sup.5 , R.sup.6, m, r and q 
have the meanings stated above and each R.sup.3 independently is hydrogen 
or an alkali metal ion, preferably sodium.

It has been found that ion exchange resins having a polymeric matrix and 
the above mentioned functional groups of formula I are useful for 
adsorbing and removal of alkaline earth meal ions such as calcium, 
magnesium, strontium and barium ions and transition metal ions from 
solutions, preferably from aqueous solution such as water. Exemplary of 
transition metal ions are those of group VIII of the periodic table of 
elements, for example of iron, cobalt, nickel, of group IIIB such as 
lanthanum, of group IIB such as zinc, cadmium and mercury, of group IIIA 
such as aluminum, gallium, of group IVA such as lead and preferably of 
group IB such as copper and silver, or UO.sub.2.sup.2-. Most preferably, 
the resins of the present invention having a polymeric matrix and 
functional groups of formula I are used for adsorption and removal of 
copper ions such as Cu.sup.2+ from an aqueous solution. 
When R.sup.1, R.sup.2, R.sup.6 and/or R.sup.7 in the functional groups of 
formula I, II and V is alkyl it has 1 to 12, preferably 1 to 6, more 
preferably 1 to 3 carbon atoms. Preferably, R.sup.1, R.sup.2, R.sup.6 
and/or R.sup.7 are hydrogen or alkyl of 1 to 3 carbon atoms. 
Preferred meanings for R.sup.1 are also --(CH.sub.2).sub.p --SO.sub.3 
R.sup.3 or --(CH.sub.2).sub.p --PO.sub.3 (R.sup.7).sub.2, particularly 
--CH.sub.2 --SO.sub.3 R.sup.3 or --CH.sub.2 --PO.sub.3 (R.sup.7).sub.2. 
When R.sup.1, R.sup.2, R.sup.6 and/or R.sup.7 is cycloalky it has 3 to 12, 
preferably 3 to 6 carbon atoms. 
When R.sup.2 is alkenyl it has 2 to 12, more preferably 2 to 6, most 
preferably 2 to 3 carbon atoms. 
When R.sup.2 is aryl, aralkyl or aralkenyl, such as phenyl or 
2-phenyl-ethenyl, it preferably has 6 to 12 carbon atoms. Preferably, 
R.sup.2 is C.sub.1-3 -alkyl or C.sub.2-3 -alkenyl, such as methyl or 
propenyl, or hydrogen. 
When R.sup.4 is aryl it preferably has 6 to 12 carbon atoms. The preferred 
aryl radical is phenyl. When R.sup.4 is alkyl it generally has 1 to 12, 
preferably 1 to 6, more preferably 1 to 3 carbon atoms. When R.sup.4 is 
cycloalkyl it preferably has 3 to 12, more preferably 3 to 6 carbon atoms. 
Preferred cations contemplated by R.sup.3 and R.sup.7 in the foregoing 
formulae are alkali metal ions such as sodium or potassium, alkaline earth 
or transition metal ions such as those mentioned above, quaternary 
ammonium ions such as NH.sub.4 + or tetraalkyl ammonium ions wherein the 
alkyl groups preferably have 1 to 12, more preferably 1 to 6, most 
preferably 1 to 4 carbon atoms, or the tetraphenylammonium ion. 
Preferably, R.sup.4, R.sup.5 and/or R.sup.7 are hydrogen; 
m is from 0 to 12, preferably from 0 to 6, more preferably from 0 to 3, 
most preferably from 1 to 3; 
n is from 1 to 12, preferably from 1 to 6, more preferably from 1 to 3; 
p is from 1 to 6; preferably from 1 to 3, more preferably 1 or 2; 
r is from 1 to 6; preferably from 1 to 3, more preferably 2; 
q is from 0 to 100, preferably from 0 to 15, more preferably from 0 to 5. 
The preferred meanings of R.sup.1 to R.sup.7, m, n, p, q and r are mainly 
dependent on the intended use of the water insoluble resins having a 
polymeric matrix and functional groups of formula I. For example, when 
using these water insoluble resins for removal of alkaline earth metal 
ions and transition metal ions from aqueous solutions, R.sup.3 preferably 
has the meaning of the sodium ion. 
The most preferred functional groups of formula I are those wherein R.sup.1 
is hydrogen, --CH.sub.2 --SO.sub.3 R.sup.3 or --CH.sub.2 --PO.sub.3 
(R.sup.7).sub.2, R.sup.2 and R.sup.4 are hydrogen, R.sup.3 and R.sup.7 
independently are hydrogen or a cation, preferably an alkali metal ion, 
most preferably the sodium ion, or a tetraalkylammonium ion, m is 1 and q 
is 0. The most preferred functional groups of formula V are those wherein 
R.sup.1, R.sup.2 and R.sup.4 are hydrogen, m is 1 and q is 0. 
The resins having a polymeric matrix and functional groups of formula I 
have a high sulfur content, in general of up to 9 weight percent, 
preferably between 6 and 9 weight percent, based on the total resin 
weight, a total sodium capacity of up to 18 g/l resin, preferably between 
9 and 18 g/l resin and a total copper capacity of up to 50 g/l resin, 
preferably between 20 and 50 g/l resin. 
Fundamental ion exchange technology is well known in the art and is for 
example described in the book "Ion exchange" F. Helfferich, McGraw-Hill 
Book Co., N.Y. 1962 and in "Ullmann's Enzyklopadie der Technischen 
Chemie", 4th Edition, Vol. 13, pages 279 ff. Various cross-linked polymers 
are useful as a matrix for the resins of the present invention. One known 
type of matrix is based on phenol/formaldehyde condensation polymers which 
are cross-linked with an aldehyde, a chlorinated hydrocarbon or an epoxy 
compound. The preferred matrixes are cross-linked polystyrene or 
poly-(alpha-methyl styrene) or cross-linked polymer beads of styrene or 
alpha-methyl styrene which is substituted at the benzene ring with 
C.sub.1-6 -alkyl, for example methyl, ethyl, tert. butyl, isopropyl, or a 
halogeno-C.sub.1-6 -alkyl, e.g. chloromethyl, or aminomethyl. The 
cross-linking agent is preferably an alkyl acrylate or a di- or polyvinyl 
compound such as trivinyl cyclohexane, ethylene glycol dimethacrylate or 
trimethylolpropane triacrylate, most preferably divinylbenzene. 
Divinylbenzene is typically copolymerized with the substituted or 
unsubstituted styrene. 
The following description of the resins of the present invention relates to 
resins which have such a preferred cross-linked styrene-divinylbenzene 
copolymer matrix, although the scope of the present invention is not 
restricted thereto. 
The resins of the present invention can have macroporous or gel-type 
(microporous) structure. The macroporous resins preferably have an average 
core diameter of more than 10 nm. The microporous resins preferably have 
an average core diameter of 0.5 to 2 nm. 
The most preferred resins of the present invention are cross-linked 
spheroido gel-type copolymer beads which have a core/shell morphology. By 
the term "core/shell morphology" it is meant that the polymeric structure 
of the copolymer beads changes from the inside to the outside of the bead. 
Such changes in polymeric structure may be somewhat gradual yielding a 
bead having a gradient of polymeric structure along the radius. 
Alternatively, said changes in polymeric structure may be relatively 
abrupt as one moves along a radius of the bead outward from the center. 
The effect in any case is that these gel-type resin beads have a 
relatively distinct core having one polymeric structure and a relatively 
distinct shell having another polymeric structure. The core/shell 
morphology of the copolymer beads is detectable using known analytical 
techniques such as those mentioned in European Patent Application 0 101 
943. The core/shell copolymer beads preferably have a shell containing a 
lower proportion of cross-linking monomers than the core. In this way, 
beads of this type will have a shell which is softer (less friable and 
more elastic) than the core of the bead. This permits the bead to 
distribute energy throughout its structure when subjected to external 
stresses and pressures while retaining its shape and integrity. It is 
believed that this improves the crush strength and resistance to osmotic 
shock of such core/shell copolymer beads. In addition to the difference in 
cross-link densities of the core and shell, the polymer in the shell can 
advantageously have a higher molecular weight than the polymers of the 
core. This also can impart mechanical strength to the bead and increase 
its resistance to osmotic shock. Accordingly, the breakage of the beads is 
reduced. The breakage of the ion exchange beads may be caused by 
mechanical or osmotic stresses, such as when the beads are subjected to 
sudden or repeated changes in electrolyte concentration. Such resins of 
the present invention having high crush strength and high resistance to 
osmotic shock are obtainable by using a corresponding resin having 
functional groups of formula II which exhibit a core/shell morphology as a 
starting material. The polymer beads useful for preparing the resins of 
the present invention are described in detail in European Patent 
Application 0 101 943. 
The resins which have functional groups of formula I may be prepared from a 
corresponding resin having functional groups of formula II 
##STR6## 
wherein R.sup.1, R.sup.4, R.sup.5, R.sup.6 and m, r and q have the meaning 
given in formula I. 
The resins having functional groups of formula II are known in the art. 
They can be prepared by converting polymer beads having the above 
mentioned cross-linked matrix, for example poly(vinyl aromatic) copolymer 
beads, most preferably of styrene/divinylbenzene copolymers, to resins 
having the functional amino groups of formula II using techniques well 
known in the art. These techniques are for example described in "Ullmann's 
Enzyklopadie der Technischen Chemie", 4th Edition, Vol. 13, pages 301 ff. 
and in European Patent Application 0 101 943. 
Resins having functional groups of formula II wherein m is zero can for 
example be prepared in a known way by the nitration of poly(vinyl 
aromatic) copolymer beads and reduction of the nitro groups which are 
bound to the aromatic ring to amino groups. 
Preferably, resins are prepared which have functional groups of formula II 
wherein m is from 1 to 12, more preferably 1. When preparing these resins, 
in a first step the beads are advantageously haloalkylated, preferably 
halomethylated, most preferably chloromethylated. Methods for 
haloalkylating the cross-linked copolymers and the haloalkylating agents 
included in such methods are also well known in the art. The 
haloalkylating agent can be substituted, e.g. by aryl. Reference is made 
thereto for the purposes of this invention. Illustrative of such are U.S. 
Pat. Nos. 2,642,417; 2,960,480; 2,597,492; 2,597,493; 3,311,602 and 
2,616,817, European Patent Application 0 087 934 and Ion Exchange by F. 
Helfferich, published in 1962 by McGraw-Hill Book Company, N.Y. and above 
mentioned "Ullmann's Enzyklopadie der Technischen Chemie". 
Typically, the haloalkylation reaction involves swelling of the 
cross-linked polymer with a haloalkylating agent, preferably 
bromomethylmethyl ether, chloromethylmethyl ether or a mixture of 
formaldehyde and hydrochloric acid, most preferably chloromethylmethyl 
ether and then reacting the polymer and haloalkylating agent in the 
presence of a Friedel-Craft catalyst such as zinc chloride, iron chloride 
or aluminum chloride. Thereby, polymer beads having groups of 
formula--(CHR.sup.4).sub.m --X wherein X is halogen, preferably chlorine, 
are prepared. 
Generally, the resins having functional groups of formula II are prepared 
in a second step from the haloalkylated bead by contacting said bead with 
an amination agent such as ammonia, a primary amine or a secondary amine. 
The amination agent preferably has the general formula IV 
##STR7## 
Representative primary and secondary amines include the methyl amine, ethyl 
amine, butyl amine, cyclohexyl amine, dimethyl amine and diethyl amine. 
Also diamines are useful such as alkylene diamines, preferably 
1,3-diaminopropane, 1,4-diaminobutane or 1,6-diaminohexane. A preferred 
amination agent is a polyamine or oligoamine such as 
EQU H--(NH--CH.sub.2 --CH.sub.2).sub.q --NH.sub.2. 
A further preferred amination agent is hexamethylene tetramine (urotropin). 
After amination and hydrolysis resins having --(CHR.sup.4).sub.m 
--NH.sub.2 groups are produced. 
Amination with a compound of formula IV generally comprises heating with 
reflux a mixture of the haloalkylated copolymer beads and at least a 
stoichiometric amount of the aminating agent to a temperature sufficient 
to react the aminating agent with the halogen atom. A reaction medium such 
as water, ethanol, methanol, methylene chloride, ethylene dichloride, 
dimethoxymethylene or combinations thereof is optionally, but 
advantageously employed. A complete amination is generally obtained within 
about 2 to 24 hours at reaction temperatures between 25.degree. C. and 
about 150.degree. C. 
Resins having functional groups of formula II wherein R.sup.5 and R.sup.6 
have a meaning other than hydrogen can be prepared by selecting those 
compounds of formula IV having the desired radicals R.sup.5 and R.sup.6 as 
an aminating agent or by converting after amination a resin having 
functional groups of formula II wherein R.sup.5 and/or R.sup.6 are 
hydrogen into a resin having functional groups of formula II wherein 
R.sup.5 and/or R.sup.6 have a meaning other than hydrogen in a known way. 
For example, the radicals alkyl, (CH.sub.2).sub.n --COOR.sup.7, 
--(CH.sub.2).sub.p --SO.sub.3 R.sup.3, --(CH.sub.2).sub.p --PO.sub.3 
(R.sup.7).sub.2 can be introduced into a group of formula II by reacting a 
group of formula II wherein R.sup.6 is hydrogen with a compound of formula 
X-alkyl, X--(CH.sub.2).sub.n --COOR.sup.7, X--(CH.sub.2).sub.p --SO.sub.3 
R.sup.3 or X--(CH.sub.2).sub.p --PO.sub.3 (R.sup.7).sub.2 wherein X is 
halogen, preferably chlorine. 
Resins having functional groups of formula II wherein R.sup.6 is --CH.sub.2 
--SO.sub.3 R.sup.3, --CH.sub.2 --COOR.sup.7 or --(CH.sub.2)--PO.sub.3 
(R.sup.7).sub.2 can for example also be prepared by subjecting a 
functional group of formula II wherein R.sup.6 is hydrogen to a 
sulfomethylation step described below, to a carboxymethylation or to a 
phosphomethylation step. The phosphomethylation can, for example, be 
carried out with formaldehyde or with a formaldehyde derivative stated 
below and with H(R.sup.7).sub.2 PO.sub.3. 
The described methods are particularly suitable for preparing resins having 
functional groups of formula II and having a poly(vinyl aromatic) 
copolymer matrix such as cross-linked polystyrene beads. Further methods 
of haloalkylation and amination of poly(vinyl aromatic) copolymer beads 
are described in WO-83/02947, WO 86/03988 and in U.S. Pat. Nos. 3,037,945, 
4,002,564 and U.S. Pat. No. 4,442,231. Further methods of preparing resins 
having aminoalkyl groups are described in U.S. Pat. Nos. 3,882,053 and 
3,989,650. 
Methods for converting polymer beads other than poly(vinyl aromatic) beads 
to resins having functional groups of formula II are illustrated in 
Helfferich, supra, pages 48 to 58. 
The resins having functional groups of formula I are prepared by reacting 
an above described corresponding resin having functional groups of formula 
II with a compound of formula III 
EQU HC(O)R.sup.2 (III) 
and a compound of formula (R.sup.3).sub.2 SO.sub.3 or (R.sup.3).sub.2 
S.sub.2 O.sub.5. Sodium sulphite, ammonium bisulphite, trimethylammonium 
sulphite, sodium bisulphite or sodium metabisulphite are preferred, sodium 
bisulphite and sodium metabisulphite being the most preferred reactants. 
Preferably, R.sup.2 is hydrogen, i.e. the compound of formula III is 
formaldehyde. Further useful aldehydes of formula III are acetaldehyde, 
crotonaldehyde, cinnamic aldehyde and HC(O)--CH(SO.sub.3 R.sup.3).sub.2. 
Sulphomethylation of monomeric amines with formaldehyde and sodium 
bisulphite is known from "Sulphonation and related reactions", by E. E. 
Gilbert, Interscience Publisher, 1965, pages 242 ff. The sulphonation is 
usually effected by mixing and heating the amine, aldehyde and sodium 
bisulphite in an aqueous solution for 3 hours in the range of 30.degree. 
C. to 100.degree. C. 
From U.S. Pat. No. 2,761,834 sulphonated methylol acrylamide polymers are 
known. They are prepared using a polymerized acrylamide as a starting 
material. Polyacrylamide is reacted with formaldehyde and with sodium 
bisulphite simultaneously or in sequence. The reaction is carried out in 
an aqueous solution at a temperature between 30.degree. C. and 100.degree. 
C. The condensation between the formaldehyde and acrylamide is carried out 
under alkaline or acid conditions, preferably at a pH of 6 to 11 at a 
temperature between 20.degree. C. and 100.degree. C. 
Sulphomethylation of polyacrylamide is also disclosed in Ind. and Ing. 
Chem. 48, pages 2132 to 2137, 1956. 
Polyacrylamide is reacted with formaldehyde in an aqueous solution at a pH 
of about 10 and the produced methylol derivative is reacted without having 
been separated from the reaction mixture with sodium bisulphite or sodium 
sulphite at a pH of about 12. Also a simultaneous reaction between 
polyacrylamide, formaldehyde and sodium bisulphite at a pH of about 12 is 
suggested. 
Unfortunately, the sulfomethylated products obtained according to these 
teachings contain rather high amounts of by-products. For example, in an 
alkaline reaction medium, sodium bisulfite reacts partially with the base 
whereby sodium sulfite is produced. When the amine, an aldehyde, such as 
formaldehyde, and sodium bisulfite are heated as suggested in the 
literature, sodium bisulfite and formaldehyde react to hydroxymethane 
sulfonic acid in an acidic reaction medium. Accordingly, the 
sulfomethylation step is sensitive to the pH of the reaction medium. 
It has been found that the process of the present invention is useful for 
preparing the water insoluble resins having a high amount of the 
functional groups of formula I above. The process can be carried out by 
mixing a corresponding resin having functional groups of formula II with a 
compound of formula III and an above mentioned salt or derivative of 
sulphurous acid in one step. The reaction is preferably carried out in an 
aqueous reaction diluent. The preferred pH value is from 5 to 13, more 
preferably from 8 to 13. The reaction temperature is preferably from 
20.degree. C. to 100.degree. C., most preferably from 40.degree. C. to 
80.degree. C. The reaction is preferably carried out during 2 to 12 hours, 
most preferably during 3 to 8 hours. The compound of formula III and the 
above mentioned derivatives of sulphurous acid are preferably used in an 
amount of 1 to 10 mols, most preferably of 2 to 4 mols, based on the molar 
amount of functional groups of formula II in the resin which is used as a 
starting material in the sulphomethylation reaction. If H.sub.2 SO.sub.3 
is used in the reaction, it is preferably prepared in situ by passing 
gaseous SO.sub.2 through an aqueous medium of a pH value of 4 to 7. 
It was surprisingly found that higher conversion rates and ion exchange 
resins with a higher level of sulphonic acid groups are obtainable when 
the sulphoalkylation according to the process of the present invention is 
carried out in two separate steps. The best results are obtained if the 
intermediate product is isolated and preferably also purified. 
In a first step a resin having functional groups of formula II as defined 
above is reacted with a compound of formula II1 to produce a resin having 
a polymeric matrix and functional groups of formula V 
##STR8## 
The resin having a polymeric matrix and functional groups of formula V and 
the mentioned method of preparing them are novel. 
This step can be carried out at a pH value of 1 to 13, preferably 5 to 13, 
more preferably 8 to 13, and is preferably carried out in the above 
mentioned temperature range and above mentioned molar ratio. Of the 
compounds of formula III formaldehyde is preferred. Advantageously 
formaldehyde is used in the reaction as an aqueous formaldehyde solution, 
for example known as formalin. However, formaldehyde can also be prepared 
in the first reaction step in situ by treating trioxane, paraformaldehyde 
or a hexamethylene tetramine/water mixture with an inorganic acid such as 
HCl, H.sub.2 SO.sub.4 or with an organic acid such as p-toluene sulfonic 
acid. The preparation of formaldehyde from trioxane or paraformaldehyde is 
described in "Ullmann's Enzyklopadie der Technischen Chemie", 4th Edition, 
Vol. 11, pages 697 and 698. 
The intermediate product which has functional groups of formula V is 
insoluble in the reaction diluent such as water and can be easily 
separated from the reaction mixture, for example by filtration. Preferably 
it is also purified, for example by washing with water. 
In a second step, the intermediate product having functional groups of 
formula V is reacted with a compound of formula (R.sup.3).sub.2 SO.sub.3 
or (R.sup.3).sub.2 S.sub.2 O.sub.5, preferably in the same molar ratio and 
the same temperature range described above with respect to the one step 
process. The second step can be carried out at a pH value of 1 to 13. 
However, it is preferably carried out in an acidic reaction medium, more 
preferably at a pH of 2 to 5, most preferably at a pH of 3 to 4. Organic 
or inorganic acids can be used for adjusting the pH value in the second 
step. For example, HCl, H.sub.2 SO.sub.4, HClO.sub.4, H.sub.3 PO.sub.4, 
acetic or p-toluene sulphonic acid are useful for adjusting the pH value. 
The acids are preferably used in about molar solutions. If H.sub.2 
SO.sub.3 is used in the reaction, it is preferably prepared in situ by 
passing gaseous SO.sub.2 through an aqueous medium of a pH value of 4 to 
7. 
Resins having functional groups of formula I wherein R.sup.1 has a meaning 
other than hydrogen can be prepared by selecting those resins having 
functional groups of formula II having the desired radical R.sup.1 or by 
converting after sulfomethylation a resin having functional groups of 
formula I wherein R.sup.1 is hydrogen into a resin having functional 
groups of formula I wherein R.sup.1 has the desired meaning other than 
hydrogen in a known way. For example, the radicals alkyl, 
--(CH.sub.2).sub.n --COOR.sup.7, --(CH.sub.2).sub.p --SO.sub.3 R.sup.3, 
--(CH.sub.2).sub.p --PO.sub.3 (R.sup.7).sub.2 can be introduced into a 
group of formula I by reacting a group of formula I wherein R.sup.1 is 
hydrogen with a compound of formula X-alkyl, X--(CH.sub.2).sub.n 
--COOR.sup.7, X--(CH.sub.2).sub.p --SO.sub.3 R.sup.3 or 
X--(CH.sub.2).sub.p --PO.sub.3 (R.sup.7).sub.2 wherein X is halogen, 
preferably chlorine. 
A resin having functional groups of formula I wherein R.sup.1 is --CH.sub.2 
--SO.sub.3 R.sup.3, --CH.sub.2 --COOR.sup.7 or --CH.sub.2 --PO.sub.3 
(R.sup.7).sub.2 can for example also be prepared by subjecting a resin 
having functional groups of formula I wherein R.sup.1 is hydrogen to a 
sulfomethylation step described above, to a carboxymethylation step or to 
a phosphomethylation step. The phosphomethylation can, for example, be 
carried out with formaldehyde or with a formaldehyde derivative stated 
above and with H(R.sup.7).sub.2 PO.sub.3. 
Radical R.sup.1 can be introduced into the functional groups of formula I 
before or subsequently to the sulfoalkylation of the resin having 
functional groups of formula II. 
As will be illustrated by the following examples, the resins having 
functional groups of formula I have a high sulphur content. The sulphur 
content can be influenced by the way of carrying out the process of the 
present invention. The resins of the present invention which comprise a 
core/shell morphology exhibit excellent mechanical strength and resistance 
to osmotic shock. When testing these resins under osmotic shock similar to 
DIN method 45406 by treating the resins with 4 molar hydrochloric acid, 
then with water, then with 4 molar potassium hydroxide and again with 
water, typically more than 95 percent, in most cases even more than 99 
percent of the bead sphericity is retained. 
The resins of the present invention having functional groups of formula I, 
in particular those wherein each R.sup.3 is hydrogen or an alkali metal 
ion, are useful for reducing the concentration of alkaline earth or 
transition metal ions in a solution containing such ions, for example in 
water treatment and in precious metal recovery. 
The resins having functional groups of formula I have amphoteric 
properties. Accordingly, they are useful for removing salts from 
solutions, for example in water treatment and purification, and in the 
processing, purification and separation of various amino acids and sugars. 
The invention is further illustrated by the following examples which should 
not be construed to limit the scope of the invention. All parts and 
percentages are by weight unless otherwise mentioned. 
The gel-type polyvinylbenzylamine resins employed in Examples 1 to 4, 7 to 
10, 14 and 15 are prepared from commercially available gel-type 
styrene/DVB resin beads by chloromethylating the beads with chloromethyl 
ether, swelling the beads in methylal (formaldehyde dimethyl acetal) and 
aminating the resin with hexamethylenetetramine in a known way. The 
preparation of the styrene/DVB resin beads and of the polyvinylbenzylamine 
resins therefrom is for example described in "Ullmann's Enzyklopadie der 
Technischen Chemie", 4th Edition, Vol 13, pages 300 ff.). 
The macroporous polyvinylbenzylamine resin employed in Example 5 is 
prepared analogously from commercially available macroporous styrene/DVB 
beads. 
The polyvinylbenzylamine resin having a core/shell morphology employed in 
Example 6 is prepared analogously from commercially available styrene/DVB 
beads having a core/shell morphology according to the teaching in 
"Ullmann's Enzyklopadie der Technischen Chemie", 4th Edition, Vol. 13, 
pages 300 ff. and in European Patent Application 0 101 943. 
The sulfur content of the resins having functional groups of formula I 
prepared according to the following Examples is determined by combusting 
the resin samples in oxygen and determining the sulfur content by ion 
chromatography. 
The total copper wet volume capacity of the sodium form of these resins is 
determined by contacting the resin beads with a solution of 60 g of 
CuSO.sub.4 --5H.sub.2 O and 120 ml of concentrated ammonium hydroxide 
diluted with water to 1 liter, washing the beads with water to remove 
excess copper and then with 2N sulphuric acid to remove the copper ions 
bound to the functional groups. The amount of copper removed from the 
beads with 2N sulphuric acid is determined using a potassium iodide/sodium 
thiosulphate oxidation/reduction titration. 
The total copper wet volume capacity is expressed as milli equivalents per 
ml of wet resin. By drying a wet resin sample having a determined volume 
and determining its weight, the total copper dry weight capacity can be 
calculated. 
The dynamic total calcium capacity for an ion exchange resin is determined 
using the sodium form of the resin at a pH of 10 to 12. The resin is 
transferred to a column equipped with a heating jacket. A chemically 
pretreated brine containing up to 2 milligrams calcium per liter of brine 
is passed through the resin at 60.degree. C. and at a flow rate of 60 bed 
volumes of brine per hour. During the run the column effluent is monitored 
for calcium by colorimetry. This is done in order to determine when the 
resin bed is no longer removing the calcium to a sufficiently low level. 
This endpoint is set at 0.05 milligrams calcium per liter brine. With the 
ion exchange resins according to the invention the calcium concentration 
is below 0.02 milligrams calcium per liter brine for most of the cycle. 
When the endpoint of 0.05 milligrams calcium per liter brine is reached in 
the effluent, the regeneration of the resin is initiated by treating it 
with acid, deionized water and caustic. The solutions which are thus 
collected from the column are analyzed for calcium and the value for the 
resin dynamic capacity is calculated. The dynamic total calcium capacity 
is expressed as grams calcium per liter of resin. 
EXAMPLE 1 
A gel-type polyvinylbenzylamine resin is used which has a cross-linked 
styrene/divinylbenzene (DVB) matrix with a DVB content of 3 percent and 
which has a weak base capacity of 1.8 meq/ml. 
50 ml of the resin is reacted with 150 ml of a 38 percent aqueous solution 
of NaHSO.sub.3 and 80 g of paraformaldehyde. The solution is acidified by 
the addition of 20 ml of concentrated HC1 and heated at 50.degree. C. for 
5 hours. The resin is separated by filtration and thoroughly washed with 
water. 
The sulfur content is 0.8 percent. 
EXAMPLE 2 
100 ml of a 38 percent aqueous solution of formaldehyde and 200 ml of a 38 
percent aqueous solution of NaHSO.sub.3 are added to 100 ml of the 
polyvinylbenzylamine resin described in Example 1. The pH is adjusted to 
13 with 25 percent aqueous NaOH and the mixture is heated at 50.degree. C. 
for 6 hours. Additional aqueous NaOH is added dropwise to maintain the pH 
at 13. The total amount of 25 percent aqueous NaOH used is 180 ml. 
The sulfur content is 3.8 percent. 
EXAMPLE 3 
50 ml of the polyvinylbenzylamine resin described in Example 1 and 100 ml 
of a 38 percent aqueous solution of formaldehyde are placed in a 500 ml 
three-necked glass vessel equipped with a stirrer and a reflux condenser. 
25 ml of 30 percent aqueous HCl is added dropwise through a funnel to 
adjust the pH to 1. The mixture is heated at 50.degree. C. for 1.5 hours. 
The resin is filtered off and thoroughly washed in water. The resin is 
placed into the vessel and 200 ml of a 37 percent aqueous solution of 
NaHSO.sub.3 is added. The pH is adjusted to 3 using 15 ml of 1 molar 
aqueous HCl. The reaction mixture is heated at 50.degree. C. for a further 
6 hours. The resin is separated by filtration and dried. 
The sulfur content is 6.1 percent. 
EXAMPLE 4 
21 ml of a 38 percent aqueous formaldehyde solution is added to 50 ml of 
the polyvinylbenzylamine resin described in Example 1. The pH is adjusted 
to 13 using 12 ml of 25 percent aqueous NaOH and the reaction mixture is 
heated at 70.degree. C. for 1.5 hours. The resin is filtered off, washed 
in water and reacted with 50 ml of a 38 percent aqueous solution of 
NaHSO.sub.3 at 70.degree. C. for 5 hours. 18 ml of 25 percent aqueous NaOH 
is added to maintain the pH at 13. 
The sulfur content is 6.9 percent. 
Examples 1 to 4 illustrate that resins with a considerably higher level of 
sulfonic acid groups are obtained when the sulfomethylation is carried out 
in two separate steps and the intermediate is separated and purified. 
EXAMPLE 5 
A macroporous polyvinylbenzylamine resin is used which has a cross-linked 
styrene/DVB matrix with a DVB content of 6 percent and which has a weak 
base capacity of 1.2 meq/ml. 50 ml of the resin is reacted with 15 ml of a 
37 percent aqueous solution of formaldehyde and 15 ml of 25 percent 
aqueous NaOH at 50.degree. C. and a pH of 13 for 1.5 hours. The resin is 
isolated, washed with water and reacted with 35 ml of a 37 percent aqueous 
solution of NaHSO.sub.3, 20 ml of 1 molar aqueous H.sub.2 SO.sub.4 at 
70.degree. C. and a pH of 3 for a further 5 hours. 
The sulfur content is 6.1 percent and the total copper capacity 0.8 meq/g. 
EXAMPLE 6 
A polyvinylbenzylamine resin is used which has a cross-linked styrene/DVB 
matrix. The resin has a core/shell morphology with a varying DVB content. 
The DVB content in the core is about 8 percent and in the shell about 2 
percent. The weak base capacity of the resin is 1.4 meq/ml. 96 ml of the 
resin is reacted with 125 ml of a 38 percent aqueous solution of 
formaldehyde and 30 ml of 25 percent aqueous NaOH at 50.degree. C. and a 
pH of 13 for 1.5 hours. The resin is filtered off, washed with water and 
placed into the reaction vessel. 400 ml of a 37 percent aqueous solution 
of NaHSO.sub.3 and 35 ml of 1 molar aqueous H.sub.2 SO.sub.4 is added and 
the reaction mixture is heated at 50.degree. C. and a pH of 3 for a 
further 5 hours. 
The sulfur content is 8.2 percent and the total copper capacity 1.3 meq/g. 
EXAMPLE 7 
50 ml of the polyvinylbenzylamine resin described in Example 1 is reacted 
with 21 ml of a 38 percent aqueous solution of formaldehyde at 50.degree. 
C. for 1.5 hours. The pH is adjusted to 13 using 12 ml of 25 percent 
aqueous NaOH. The resin is filtered off, washed and placed into the 
reaction vessel. 50 ml of a 37 percent aqueous solution of NaHSO.sub.3 and 
15 ml of 1 molar aqueous H.sub.2 SO.sub.4 are added and the mixture is 
heated at 50.degree. C. for a further 5 hours. The resin is thoroughly 
washed with water and dried. 
The sulfur content is 8.9 percent and the total copper capacity is 1.6 
meq/g. 
EXAMPLE 8 
100 ml of the polyvinylbenzylamine resin described in Example 1 is stirred 
in a solution of 108 g of Na.sub.2 SO.sub.3 in 225 ml of a 38 percent 
aqueous solution of formaldehyde. 30 ml of 25 percent aqueous NaOH is 
added and the reaction mixture is heated at 50.degree. C. for 5 hours. The 
resin is separated by filtration and washed with water repeatedly. 
The sulfur content is 2.4 percent. 
EXAMPLE 9 
50 ml of the polyvinylbenzylamine resin described in Example 1 is reacted 
with 100 ml of a 38 percent aqueous solution of formaldehyde and 30 ml of 
25 percent aqueous NaOH at 50.degree. C. and a pH of 13 for 1.5 hours. The 
resin is isolated, washed in water and placed into the reaction vessel. A 
saturated solution of 109 g of Na.sub.2 SO.sub.3 in 240 ml of water and 15 
ml of 1 molar aqueous H.sub.2 SO.sub.4 are added and the mixture is heated 
at 50.degree. C. and a pH of 3 for 5 hours. 
The sulfur content is 3.1 percent. 
EXAMPLE 10 
50 ml of the polyvinylbenzylamine resin described in Example 1 is reacted 
with 21 ml of a 38 percent aqueous solution of formaldehyde and 15 ml of 
25 percent aqueous NaOH at 50.degree. C. for 1.5 hours. The resin is 
filtered off, washed with water and placed into the reaction vessel. A 
solution of 34 g of Na.sub.2 S.sub.2 O.sub.5 in 60 ml of water and 20 ml 
of 25 percent aqueous NaOH are added and the mixture is heated at 
50.degree. C. for 5 hours. 
The sulfur content is 7.2 percent. 
EXAMPLE 11 
50 ml of a gel-type chloromethylated resin which has a cross-linked 
styrene/DVB matrix with a DVB content of 1.8 percent and a wet volume 
capacity of 1.4 meq/ml is swollen with 75 ml of methylal (formaldehyde 
dimethylacetal) for 1 hour at 40.degree. C. 200 ml of diethylenetriamine 
is added and heated for a further 5 hours at 60.degree. C. After cooling 
to room temperature the resin is washed with diluted hydrogen chloride to 
remove the excess of the amine, then with water. The weak base capacity is 
2.8 meq/ml. 
60 ml of the produced polyvinylbenzylamine resin is added to 150 ml of a 37 
percent aqueous solution of formaldehyde and 10 ml of 25 percent aqueous 
NaOH. The reaction mixture is heated to 50.degree. C. for 3 hours and the 
resin is repeatedly washed with water. Then the resin is heated for a 
further 6 hours in 360 ml of a 38 to 40 percent aqueous solution of 
NaHSO.sub.3 and 25 ml of I molar aqueous H.sub.2 SO.sub.4. After the resin 
has been washed and dried, its total dry weight copper capacity is 1.2 
meq/g. 
EXAMPLE 12 
150 ml of a macroporous chloromethylated resin which has a cross-linked 
styrene/DVB matrix with a DVB content of 6.4 percent and a wet volume 
capacity of 1.1 meq/ml is swollen in 120 ml of methylal for 1 hour at 
40.degree. C. 300 ml of tetraethylenepentamine is added and the mixture is 
heated for 5 hours at 60.degree. C. After washing the resin with diluted 
hydrogen chloride and water the weak base capacity is 2.2 meq/ml. 
100 ml of the produced polyvinylbenzylamine resin is reacted with 100 ml of 
a 37 percent aqueous solution of formaldehyde and 10 ml of 25 percent 
aqueous NaOH for 3 hours at 50.degree. C. The resin is washed neutral with 
distilled water and reacted with 180 ml of a 38 to 40 percent aqueous 
solution of NaHSO.sub.3 and 16 ml of 1 molar aqueous H.sub.2 SO.sub.4 for 
6 hours at 90.degree. C. After washing with water the wet volume capacity 
of the resin is 0.5 meq/ml and the total dry weight copper capacity is 1.0 
meq/g. 
EXAMPLE 13 
Example 11 is repeated, however, hexamethylenetetramine (urotropin) is used 
as the amination agent instead of diethylene triamine and the amination is 
carried out at 48.degree. C. The weak base capacity of the produced 
polyvinylbenzylamine resin is 1.3 meq/ml. The sulfomethylation of this 
resin is carried out as described in Example 11. The total dry weight 
copper capacity is 1.3 meq/g. 
EXAMPLE 14 
a) Sulfomethylation 
100 ml of the polyvinylbenzylamine resin described in Example 1 is reacted 
with 150 ml of a 38 percent aqueous solution of formaldehyde and 30 ml of 
25 percent aqueous NaOH for 3 hours at 70.degree. C. The resin is filtered 
off, washed with water and reacted with 400 ml of a 38 to 40 percent 
aqueous solution of NaHSO.sub.3 and 30 ml of 1 molar aqueous H.sub.2 
SO.sub.4 for 6 hours at 70.degree. C. The total copper wet volume capacity 
is 0.8 meq/ml. The total copper dry weight capacity is 1.6 meq/g. 
b) Phosphomethylation 
40 ml of the produced resin is further phosphomethylated with 35 g of 
H.sub.3 PO.sub.3 dissolved in 55 ml of water. 13 g of paraformaldehyde and 
11 ml of concentrated HCl are successively added to the reaction mixture 
and heated to 95.degree. C. for 3.5 hours. After the resin has been washed 
with distilled water, the total copper wet volume capacity is 2.6 meq/ml. 
The total copper dry weight capacity is 5.0 meq/g. The dynamic total 
calcium capacity is 21.8 g calcium/1 resin. 
EXAMPLE 15 
120 ml of the sulfomethylated polyvinylbenzylamine resin produced according 
to Example 14a) is brought into its sodium form by treatment with 300 ml 
of 5 percent aqueous NaOH. The caustic is removed from the beads and the 
resin is added to the reactor. A solution of 104 g of chloroacetic acid in 
180 ml of water is prepared. The solution is cooled in an ice-bath to less 
than 10.degree. C. 45 g of 50 percent aqueous NaOH is slowly added keeping 
the temperature at less than 40.degree. C. The solution is added to the 
reactor. An additional amount of 10 g of 50 percent aqueous NaOH is added 
and the flask is heated to 65 to 70.degree. C. The reaction is held at 
this temperature for a total of 4 hours and then cooled to room 
temperature. The sodium chloroacetate solution is removed from the beads. 
The resin is washed two times with 500 ml of water stirring for 30 
minutes. The produced resin is washed several times on a fritted glass 
filter. The total copper wet volume capacity is 1.3 meq/ml. The total 
copper dry weight capacity is 2.6 meq/g. The dynamic total calcium 
capacity is 5.8 g calcium/1 resin. 
Examples 14 and 15 illustrate that resins which are sulfomethylated and 
phosphomethylated have a considerably higher copper and calcium capacity 
than resins which are only sulfomethylated or 
sulfomethylated/carboxymethylated. 
EXAMPLE 16 
20 ml of the sulfomethylated polyvinylbenzylamine resin produced according 
to Example 11 is reacted with 17.5 g of H.sub.3 PO.sub.3 dissolved in 28 
ml of water. 6.9 g of paraformaldehyde and 6 ml of concentrated HCl are 
successively added. The reaction mixture is heated at 90.degree. C. for 
3.5 hours. After washing the resin with water, the total wet volume copper 
capacity is 0.7 meq/ml and the total dry weight copper capacity is 1.3 
meq/g.