METHOD FOR PREPARATION OF HYDROPHILIC POLYMERIC ION EXCHANGING GELS

GELS POLYMERIQUES, HYDROPHILES D'ECHANGE IONIQUE

English Abstract

Method for preparation of hydrophilic polymeric ion exchanging
mols.
ABSTRACT OF THE DISCLOSURE
The invention relates to preparation of synthetic ??cro-
porous ion-exchanging materials by a ternary copolymeriza-
tion of hydrophilic monomers containing non-ionogeneous
groups with monomers containing ionogenous groups and cross-
linking monomers in an aqueous dispersion in the presence
of inert components and suspension stabilizers. Hydroxy-
alkyl, oligoglycol and polyglycol esters and ?-substituted
or unsubstituted amides of acrylic and methacrylic acid
are used as the hydrophilic monomers; compounds CH2=(?)COX,
where R = H or CH3, X = -(R1N(R2)R3, -OR1SO3H, -NHR1N(R2)R3
or -NHR1SO3H, R1 = alkylene and R2 and R3 = H, alkyl, hydro-
xyalkyl or aminoalkyl, acrylic and methacrylic acid serve
as the ionogenous monomers; the crosslinking agents are
selected from a group of monomer consisting of alkylene,
oligoglycol or polyglycol diacrylates and dimethacrylates,
alkylenebisacrylamides, alkylenebismethacrylamides, divinyl-
benzene and other compounds containing more than 2 polymeriz-
able acryloyl or methacryloyl groups. The invented materials
are suitable above all for isolation and chromatographic
separation of sensitive compounds of the biological origin.
- 1 -

Claims

The embodiments of the invention in which an exclu-
sive property or privilege is claimed are defined as follows:
1. Method for the preparation of an ion-exchange
member having a hydrophilic character, macro or semi-macropores
containing ionogenous groups and characterized by only slight
swelling in aqueous solutions, said method comprising the ternary
copolymerization in an aqueous dispersion medium in the presence
of suspension stabilizer and inert component selected from the
group consisting of hexanol, cyclohexanol, and mixtures of
88.8-98.5 wt. parts of cyclohexanol with 10-19.5 wt. parts of
dodecylic alcohol, of
a) hydrophilic monomers containing non-ionogenous groups,
said hydrophilic monomers containing functional hydroxyl
or amide groups selected from the group of compounds
consisting of hydroxyalkyl acrylates, hydroxyalkyl methacrylates,
oligo-or-polyglycol acrylates, oligo-or-polyglycol metha-
crylates, acrylamides, methacrylamides, with
b) monomers containing ionogenous groups and selected from
the group consisting of acrylic acid, methacrylic acid
and monomers represented by the formula
<IMG>
wherein:
R = H or CH3 and
x is
<IMG> ,
-OR1SO3H,
<IMG> , or
-NH-R1SO3H
11

R1 is alkylene
R2 and R3 are hydrogen, alkyl, hydroxyalkyl or amino-
alkyl radicals, and
c) 30.0 to 39.1% by weight of crosslinking agents
selected from the group consisting of alkylene diacry-
lates, alkylene dimethacrylates, oligoglycol and poly-
glycol diacrylates, oligoglycol and polyglycol dimetha-
crylates, alkylenebisacrylamides, alkylenebismethacrylates
and divinylbenzene.
2. Method according to claim 1, wherein th monomer
containing ionogenous groups is diethylaminoethyl methacrylate.
3. An ion-exchange member having a hydrophilic char-
acter, macro or semi-macropores containing ionogenous groups and
characterized by only slight swelling in aqueous solutions, said
ion-exchange member being formed of a material produced by the
ternary copolymerization in an aqueous dispersion medium in the
presence of suspension stabilizer and inert component selected
from the group consisting of hexanol, cyclohexanol, and mixtures
of 88.8-98.5 wt. parts of cyclohexanol with 10-19.5 wt. parts
of dodecylic alcohol, of
a) hydrophilic monomers containing non-ionogenous groups,
said hydrophilic monomers containing functional hydro-
xyl or amide groups selected from the group of compounds
consisting of hydroxyalkyl acrylates, hydroxyalkyl metha-
crylates, oligo-or polyglycol acrylates, oligo-or-poly-
glycol methacrylates, acrylamides, methacrylamides,
b) monomers containing ionogenous groups and selected from
the group consisting of acrylic acid, methacrylic acid
and monomers represented by the formula
<IMG>
12

wherein:
R = H or CH3,and
x is
<IMG> ,
-OR1SO3H,
<IMG> , or
-NH-R1SO3H
R1 is alkylene
R2 and R3 are hydrogen, alkyl, hydroxyalkyl or
aminoalkyl radicals; and
c) 30.0 to 39.1% by weight of crosslinking agents
selected from the group consisting of alkylene diac-
rylates, alkylene dimethacrylates, oligoglycol and
polyglycol dimethacrylates, alkylenebisacrylamides,
alkylenebismethacrylates and divinylbenzene.
4. The ion-exchange member of claim 3, wherein the
monomer containing ionogenous groups is diethylaminoethyl
methacrylate.
13

Description

1070896
The invention relates to ion exchangers prepared by
copolymerization of hydrophilic non-ionogenous monomers with
ionogenous monomers resulting in formation of a hydrophilic
ion-exchanging gel; suitable above all for isolat~on and
chromatographic separation of sensitive compounds, usually of
a biological origin, as are proteins, polypoptides, entigens,
enzymes, nucleic acids and their high-molecular-weight fragments,
as well as for numerous further possible applications.
Isolation is one from fundemental and very important
chemical operations and materials with groups capable to exchan-
ge ions are very important tools used in this process. However,
ion exchangers have numerous further applications which are
not less important. Ion-exchanging materials manufactured
till the present time did not satisfy always the requirements
Eor their use, although already a great number of them was
developed. The known materials are of the natural origin
(various aluminosilicates , e.g. zeolites), or prepared by a
simple modification of natural materials (e.g. sulfonated coal),
or especially synthetic materials inorganic as well as organic.
Only a limited number of inorganic synthetic ion exchangers
is used; besides synthetic zeolites, also phosphates, molybdates
and tungstates of thorium, titanium and namely of zirconium are
important at the present time. A great number of organic
synthetic ion exchangers has been prepared and is produced,
starting with the oldest phenol - formaldehyde and urea resins
to the up to date copolymers of acrylic acid and its deriva-
tives with divinylbenzerle and styrene - divinylbellzene ion
exchangers.
The above mentioned types of ion exchangers are mostly
unsuitable for the purpose of isolation and chromatographic
separation of sensitive compounds of the biological origin,
which have a complicated sterical structure (primary, secondary
- 2 - ~
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1070896
and tertiary structure), as are proteins, polypeptides, nucleic
acids and their fragments. Either they have unsuitable ionogenous
properties (the inorganic ion exchangers) or strong hydrophobic
interactions occur on the surface of hydrophobic a-romatic matrices
which destroy the higher structures of sensitive biological
products and denaturate them (the organic ion exchangers).
Therefore, application of these ion exchangers brings about
an excessive loss of the valuable material or is impossible at
all. Ir. addition to it, the relatively high number of cross
links allows to employ only the surface functional groups
for the sorption of natural macromolecules. This is the reason
why the hydrophilic ion exchangers were sought and prepared,
which do not denaturate the natural polymers and are more
accessible for macromolecules. Among these exchangers are namely
ion-exchanging derivatives of cellulose (e.g. carboxymethyl-
cellulose, diethylaminoethylcellulose, etc.) and iron-exchanging
derivatives of polydextran (e.g. carboxymethyl, diethylamino-
ethyl, sulfoethyl or sulfopropyl, and quarternized aminoethyl
derivatives of polydextran). An advantage of these ion exchangers
is the polysaccharide structure of chains with numerous hydro-
philic hydroxyl groups~ with very sparce cross links (at poly-
dextrans) or the fibrillous structure of cellulose; broad pores
enable permeation of macromolecules to the functional groups
of these ion exchangers. At the present time, these products
are supplied by several producers for the purpose of sorption
and chromatography of proteins, polypeptides, nucleic acids,
their fragments and other compounds and are employed not
only in the laboratory scale but also in plants.
A disadvantage of these products is their relatively
~0 low mechanical strength and the low chemical stability, because
materials of the biological origin (cellulose, polydextran)
which are neither mechanically nor chemically resistant are
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~0'70896
used for their preparation. Another disadvantage is the shape
and properties of particles. Bunches of cellulose fibrils
cannot be prepared in a globular form, even when the natural
fibers are now shortened for the preparation of ion exchangers.
The packing of a column acquires a form of the pressed felt
at higher pressures and the column became clogged. Therefore,
these materials are not perspective for the modern developing
liquid chromatography where still higher through-flow rates
and pressures are used and globular particles are required.
This shape of particles is not very convenient also for the
purpose of production plants.
Polydextrans are produced in a form of globules which
are, however, very soft and considerably change their volume in
\

~07~)896
dependence on the ionic strength of a solution. For this
reason, they do not allow regeneration and washing with water
in the columns. The column has to be packed ayain for each
use and this fact makes the laboratory application and
especially the plant application difficult. In addition to
this, deformation of the soft spheroids and clogging of
a>l~ns take place at increased through-flow rates and higher
pressures. Neither this type of ion exchangers is therefore
perspective for purposes of the modern liquid chromatography.
~th types vf ion-exchanging derivatives - cellulose and
pDlydextran derivatives - are sensitive to the extreme values
of pH, especially at the increased temperature, and to the
oxidation and other chemical agents. Besides this, they are
decomposed by some hydrolytic enzymes and are readily attacked
by ~nicro-or~anlsms.
The present invention relates to a method for
the preparation of an ion-exchange member having a hydro-
philic character, macro or semi-macropores containing
ionogenous groups and characterized by only slight swelling
in aqueous solutions, said method comprising the ternary
copolymerization in an aqueous dispersion medium in the
presence of suspension stabilizer and inert component se-
lected from the group consisting of hexanol, cyclohexanol,
and mixtures of 88.8-98.5 wt. parts of cyclohexanol with
10-19.5 wt. parts of dodecylic alcohol, of
a) hydrophilic monomers containing non-ioncgenous
groups, said hydrophilic monomers containing func-
tional hydroxyl or amide groups selected from the
group of compounds consisting of hydroxyaIkyl acry-
lates, hydroxyalkyl methacrylates, oligo-or-

~0708~6
polyglycol acrylates, oligo-or polyglycol metha-
crylates, acrylamides, methacrylamides, with
b) monomers containing ionogenous groups and selected
from the group consisting of acrylic acid, metha-
crylic acid and monomers represented by the formula
R
CH2=C -COX
wherein:
R = H or CH3 and
x is R2
-Rl-N~
R3
-ORlS03H,
~R2
-NH-Rl-N\ , or
1 o3
Rl is alkylene
R2 and R3 are hydrogen, alkyl, hydroxyalkyl or
aminoalkyl radicals; and
3 ~. ~ t ~ 3Cl 1 70
c) ~4-.~ to 3 O partc by weight of crosslinking agents
selected from the group consisting of alkylene diac-
rylates, alkylene dimethacrylates, oligoglycol and
polyglycol diacrylates, oligoglycol and polyglycol
di.methacrylates, alkylenebisacrylamides, alkylene-
bismethacrylates and divinylbenzene.
The resulting type of the fund~mental macroporous or
semi-macropc;rou~, aero-xerogel matrix prov:i.des the :ion
exchan~ers
C.

1070E396
with the high mechanical stability, the pressure resistance
and the chemical stability. The formed derivatives are resis-
tant towards the acidic and alkaline hydrolysis, oxidation and
effects o~ organic solvents. As the initial monomers are not
compounds of the biological origin which may be suitable
substrates for microorganisms, the prepared gels are also
resistant towards contamination with germs or moulds. The
copolymers swell only very little in aqueous solutions and
their particles do not change the size with the changing ionic
strength even at hiyh capacities of the ion exchangers. Con-
sequently, the ion exchangers are easy to regenerate. The
easy control of the pore size within broad limits during the
synthesis allows penetration of natural macromolecular polymers
up to the molecular weight of millions preserving all advanta-
ges and enables in this way the preparation of materials
with optimum fitting to the given purpose. Besides this,
selectivity of the ion exchangers to molecules of various
size may be achieved by choosing the suitable porosity.
These properties make the application of the new ion
exchangers advantageous both in the laboratory and production
scale in common as well as in pressure columns and enable
their use in the developing liquid chromatography and in
sorption for production purposes by a column or a batch pro-
cedure. Because the new materials do not denaturate biopoly-
mers, they are suitable for sorption and chromatographic se-
paration of biopolymers without limiting their practical use
to this. These ion exchangers may be prepared in the form of
globular spheroids or also as blocks, granu:Les, membranes,
tubes, fibers, foils or belts. Threads or strings may be
woven into a form of ion-exchanging fabric for the purpose
of the continuous sorption and desorption on a conveyer belt.
Procedures for preparation of these ion exchangers

~C~70896
are further elucidated in examples, without, however, limiting
the scope of the invention to them.
EXAMPLE 1
A suspension copolymerization of 32.7 wt. parts of
2-hydroxyethyl methacrylate, 24.5 wt. parts of N,N-diethyl-
aminoethyl methacrylate, and 24.5 parts of ethylene dimetha-
crylate was carried out in 88.8 parts of cyclohexanol, 19.5
parts of dodecylic alcohol and ~00 parts of water in a glass
autoclave of the volume 1 liter equipped with a stainless-steel
anchor-shaped stirrer with continuously controllable revolutions,
a thermometer and a thermostating jacket for 12 hours at 80C.
The suspension was stabilized with 6 parts of polyvinylpyrro-
lidone (BASF, Mw = 750,000). Azobisisobutyronitrile (0.8
parts) was used as the initiator of radical polymerization.
After completion of the polymerization, the gel was thoroughly
washed with water and ethanol, fractionated according to the
particle size, and titrated to determine its exchange capacity
in the usual way (0.29 mequiv/g). The ternary copolymerizations
with varying initial concentration of N,N-diethylaminoethyl
methacrylate was carried out in the similar way. Fig. 1 shows the
dependence of the exchange capacity of ternary copolymers on
the initial concentration of the ionogenous monomer. The exchan-
ge capacities of the product are plotted on the y-axis in
miliequivalents par 1 g of the dry polymer, the concentration
of N,N-diethylaminoethyl methacrylate is plotted on the x-axis
in percent of the initial monomer mixture.
EXAMPLE 2
A strongly acidic cation exchanger was prepared in
the similar way as in Example 1, with the distinctioll that 2-
sulfoethyl methacrylate was used as the ionogenous monomer.
The globular particles of the product were isolated and the
exchange capacity was determined analogously as in Example 1
.. .. . .

~)70896
(i.39 mequiv/g).
EXAMPLE 3
The same apparatus was used as in Example 1 for
copolymerization of 41.6 wt. parts of 2-hydroxyethyl, acrylate,
8.2 parts of N,N-diethylaminoethyl methacrylate and 32 parts
of diethylene glycol dimethacrylate in the presence of 90 parts
of cyclohexanol and 10 parts of lauryl alcohol. The exchange
capacity of the product was determined after its isolation and
washing.
EXAMPLE 4
A polymer having the macroporous structure was prepared
analogously as in Example 1, with the distinction that N,N-
dimethylaminoethyl methacrylate was used as the ionogenous
monomer.
EXAMPLE 5
The same apparatus as in Example 1 was used for
copolymerization of 33.5 wt. parts of diethylene glycol
monomethacrylate, 32 parts of ethylene dimethacrylate and
16.5 parts of N-(2-sulfoethyl)methacrylamide in the presence
of 100 parts of cyclohexanol. The macroperous polymer was
obtained in the form of globular particles and was washed with
water and ethanol and fractionated according to the particle
size on screens. The fraction 100 - 200~um was used for
determination of the exchange capacity (0.73 mequiv/g).
EXAMPLE 6
A polymer was prepared analogously to the Example 1
with the distinction that methacrylic acid (14.9 parts) was
used as the ionogenous monomer and the ternary copolymerization
was carried out with 35 parts of 2-hydroxyethyl methacrylate
and 32 parts of ethylene dimethacrylate in the presence of 98.5
parts of cyclohexanol and 10 parts of dodecylic alcohol. The
resulting polymer was washed, fractionated and used as the

1~708g6
weak acid cation exchanger.
EXAMPLE 7
Analogously to Example 1, 33 wt. parts of 2-hydroxy-
ethyl acrylate, 32 wt. parts of methylenebisacrylamide and
18 parts of diethylaminoethyl acrylate were copolymerized
in the presence of 100 parts of hexanol. The polymer was obtain-
ed in the form of globular particles and exhibited the exchange
Gapacity 0.7 mequiv/g.
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