Synthesis and physicochemical properties of chelating sorbents containing functional groups of N-aryl-3-aminopropionic acids

Article abstract of DOI:10.1007/s11172-006-0339-3

Two types of chelating sorbents with different types of addition of iminodipropionate groups to a polymeric matrix were synthesized: carboxyethylated aminopolystyrene (sorbent 1) based on linear polystyrene and carboxyethylaminomethylpolystyrene (sorbent 2) based on the copolymer of styrene and divinylbenzene. The ionization constants and concentrations of functional groups of the sorbents (exchange capacity for hydrogen ions) were determined. The sorbents exhibit high selectivity for copper(II) ions with the maximum of sorption from ammonia-acetate buffer solutions lying in a range of pH 5.0-7.5. The time needed for a solution of copper(II)-sorbent system with continuous stirring to reach exchange equilibrium is 3.5 and 2 h for sorbents 1 and 2, respectively. The exchange capacity for copper(II) ions is 2.54 and 0.10 mmol g^-1, respectively. Springer Science+Business Media, Inc. 2006.

Full text of DOI:10.1007/s11172-006-0339-3

828
Russian Chemical Bulletin, International Edition, Vol. 55, No. 5, pp. 828—834, May, 2006
Synthesis and physicochemical properties of chelating sorbents
containing functional groups of Nꢀarylꢀ3ꢀaminopropionic acids
L. K. Neudachina,aꢀ Yu. G. Yatluk, N. V. Baranova, A. V. Pestov, A. A. Vshivkov,
b
a
b
a
a
a
A. Yu. Plekhanova, and M. V. Zorina
aA. M. Gorky Ural State University,
5
1 prosp. Lenina, 620083 Ekaterinburg, Russian Federation.
Fax: +7 (343) 261 5978. Eꢀmail: Ludmila.Neudachina@usu.ru
Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences,
b
2
0 ul. S. Kovalevskoi, 620219 Ekaterinburg, Russian Federation.
Fax: +7 (343) 374 1139. Eꢀmail: eop@ios.uran.ru
Two types of chelating sorbents with different types of addition of iminodipropionate
groups to a polymeric matrix were synthesized: carboxyethylated aminopolystyrene (sorbent 1)
based on linear polystyrene and carboxyethylaminomethylpolystyrene (sorbent 2) based on the
copolymer of styrene and divinylbenzene. The ionization constants and concentrations of
functional groups of the sorbents (exchange capacity for hydrogen ions) were determined. The
sorbents exhibit high selectivity for copper(II) ions with the maximum of sorption from ammoꢀ
nia—acetate buffer solutions lying in a range of pH 5.0—7.5. The time needed for a solution of
copper(II)—sorbent system with continuous stirring to reach exchange equilibrium is 3.5 and
2
0
h for sorbents 1 and 2, respectively. The exchange capacity for copper(II) ions is 2.54 and
.10 mmol g–1, respectively.
Key words: synthesis, carboxyethylaminopolystyrene, carboxyethylaminomethylpolystyrene,
ionization constant, exchange capacity for hydrogen ions, exchange capacity for copper(II)
ions, selectivity of ion exchange.
Chelating sorbents are widely used for separating, isoꢀ
The purpose of the present work is to synthesize two
sorbents with different types of addition of iminodiꢀ
propionate groups to the polymeric matrix and to study
their physicochemical and analytical properties.
lating, and concentrating metal ions as well as for removal
of interfering ions from the examined solution at the preꢀ
liminary stage of analysis.1
—3
Sorbents containing iminodiacetate groups, for exꢀ
ample, Chelex 100, Dowex Aꢀ1, ANKBꢀ10, ANKBꢀ35,
are used for the group isolation of transition metal ions.
Results and Discussion
4
—6
They sorb ions in a wide pH range rather rapidly and have
high sorption capacity; they are hardly suitable for isoꢀ
Synthesis of carboxyethylaminopolystyrene. Carboxyꢀ
ethylaminopolystyrene (sorbent 1) was synthesized by
the method of polymerꢀanalogous transformations
(Scheme 1).
lating individual transition metal ions, in particular,
copper(II).2
,3,7
The known methods for preparation of
chelating sorbents are mainly based on two procedures:
polymerꢀanalogous transformations of the ready polymers
for the purpose of introduction of chelating functional
groups and polymerization (polycondensation) of comꢀ
pounds containing the corresponding groups.1,4,8 The inꢀ
troduction of chelating groups of a new type into the
sorbent structure always requires the development of origiꢀ
nal procedures of synthesis.
Crosslinked polystyrene containing 2% divinylbenzene
(DVB) is used, as a rule, for the preparation of styrene
2
,8
copolymer sorbents. In the present work, we used linꢀ
ear polystyrene for the synthesis, and partial crosslinking of
the polymer occurred during both nitration and carboxyꢀ
1
0
ethylation.
Fuming nitric acid,11 its mixture with sulfuric acid,12
and a mixture of sulfuric acid and potassium nitrate can
be used for polystyrene nitration. Performance testing
showed that only nitration with fuming nitric acid gave a
uniformly nitrated object, which is necessary to predict
the sorption properties of the synthesized products.
Nitropolystyrene is reduced with tin—hydrochloric
acid13 and tin chloride—hydrochloric acid mixtures in
The properties of chelating sorbents are mainly deterꢀ
1
mined by the nature of functional groups. Therefore, it is
of considerable interest to introduce fragments of the earꢀ
9
lier synthesized N,Nꢀdi(2ꢀcarboxyethyl)anilines, which
are highly selective for copper(II) ions, into the chelating
sorbents.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 800—806, May, 2006.
066ꢀ5285/06/5505ꢀ0828 © 2006 Springer Science+Business Media, Inc.
1

New sorbents with aminopropionate groups
Russ.Chem.Bull., Int.Ed., Vol. 55, No. 5, May, 2006
829
Scheme 1
d(pH)/dC
0
0
0
0
0
0
.40
.35
.30
.25
.20
.15
2
4
CKOH/mmol g–1
Fig. 1. Differential curve of potentiometric titration of sorbent 1,
µ = 0.1 M KCl, T = 20±2 °C.
carried out in excess acrylic acid, aminopolystyrene with
a high degree of carboxyethylation can be obtained.
Synthesis of carboxyethylaminomethylpolystyrene. The
sorbent containing residues of methyliminodipropionic
acid (sorbent 2) was synthesized by the method of polyꢀ
merꢀanalogous transformations (Scheme 2).
water13 or alcohol
11,14
and sodium polysulfide,11 sodium
Two main methods of the synthesis are described. The
first method is the interaction of chloromethylated polyꢀ
styrene with an intermediate of the functional group,
dithionite,1 or phenylhydrazine.16 Tin(II) chloride in a
hydrochloric acid—alcohol mixture is used most freꢀ
quently for reduction. It is known1 how difficult is to
wash off the reduced product from residues of tinꢀconꢀ
taining compounds. As our experiments showed, the
amount of ash (residue from burning off the polymer
samples) is 1—2%, which is inappropriate for subsequent
analytical studies. In other cases, the nitro groups are not
completely reduced. In the synthesis we used reduction
with phenylhydrazine, because a minimum number of
unreduced nitro groups is remained after this process.
The carboxyethylation of aromatic amines with acrylic
5
3
19
20—22
viz., dinitrile or dimethyl iminodipropionate.
The
second method includes the transformation of chloroꢀ
methylated polystyrene into aminomethylpolystyrene folꢀ
2
3
lowed by the addition of an acrilic acid derivative. It is
2
3
shown that the variation of the synthesis conditions alꢀ
lows one to prepare sorbents with different exchange caꢀ
pacities (characteristics). In the present work, we used the
first method of synthesis.
Acidꢀbase properties of the sorbents. The acidꢀbase
properties of the sorbents were studied by direct potentioꢀ
metric titration in the case of sorbent 1 (Fig. 1) and by the
method of individual weighed samples for sorbent 2
(Fig. 2). The titration curves of the both sorbents exhibit
one jump, which can be attributed to the ionization of the
acid can afford both monocarboxyethylated and diꢀ
carboxyethylated products.1
7,18
We found no published
data on aminopolystyrene carboxyethylation. The study
of this reaction showed that the carboxyethylation of
aminopolystyrene with solutions of acrylic acid in organic
solvents (chloroform, benzene, carbon tetrachloride) gave
monocarboxyethylation products. When the reaction is
2
4
betainic proton of the amino group. No dissociation of
the carboxyl groups was detected by potentiometric meaꢀ
surements.
Scheme 2

830
Russ.Chem.Bull., Int.Ed., Vol. 55, No. 5, May, 2006
Neudachina et al.
pH
R (%)
9
8
0
0
1
0
8
6
1
1
2
3
4
5
6
70
2
6
5
4
3
2
1
0
0
0
0
0
0
7
0
.5
1.0
1.5
2.0
CKOH/mmol g–1
Fig. 2. Curves of potentiometric titration for sorbent 2 obtained
using the method of individual weighed samples. Equilibration
time is 5 h (1), 1 (2), 2 (3), 3 (4), 5 (5), 9 (6), and 14 days (7);
µ = 0.1 M KCl, T = 20±2 °C.
1
2
3
4
5
6
7
8
pH
Fig. 3. Plots of the degree of extraction (R) of copper(II) ions on
sorbents 1 (1) and 2 (2) vs. pH of buffer solutions at C
In the case of sorbent 2, the presence of a methylene
bridge between the nitrogen atom of the iminodiproꢀ
pionate group and benzene ring increases the basicity of
the nitrogen atom, which becomes apparent from the
shapes of curves in Figs 1 and 2. The pH jump for sorꢀ
bent 1 is rather pronounced only when the differential
form of the titration curve is used (see Fig. 1), whereas for
sorbent 2 the jump is only ~2 pH units (see Fig. 2). Sorꢀ
bent 2 is a crosslinked polymer and, hence, it is only after
CuII
=
–
4
–4
–1
5
•10 (1) and 1•10 mol L (2).
bents 1 and 2, the maximum sorption from a ammoꢀ
nia—acetate buffer solution is achieved in a range of
pH 5.0—7.5. The optimum pH values at which the highꢀ
est amounts of copper(II) ions are sorbed from solutions
are 6.0—6.5 for both sorbents. These pH intervals agree
with the optimum pH values of complexation of monoꢀ
meric arylaminopropionic acids with copper(II) ions
9
days when the titration curve of this sorbent becomes
timeꢀindependent (see Fig. 2, curve 6).
2
6
The ionization constants were calculated by the
(pH 5.5—8.0).
1
Henderson—Hesselbach equation. The values obtained
The changes in the IR spectra of the complexed ionꢀ
exchange resins as compared to the IR spectra of the
initial ionꢀexchange resins can serve as a direct proof for
the formation of a coordination bond between the metal
for sorbent 1 are comparable with the ionization conꢀ
stants for the monomeric analog (Table 1). The differꢀ
ences are caused, most likely, by the presence of remainꢀ
ing nitro groups or amino groups not only in the paraꢀ but
also in the orthoꢀposition. We could not find the value of
the ionization constant for benzyliminodipropionic acid
but that for benzyliminodiacetic acid is published.2
The static exchange capacities (SEC) for hydrogen
atoms for sorbents 1 and 2 determined from the data of
potentiometric titration are given in Table 1.
8
ion and ionogenic groups of the polymer. The IR spectra
of sorbent 1 before and after sorption (Table 2) exhibit
almost no shift of the absorption band of the carbonyl
group and no noticeable signals indicating the formation
of the O—Cu bond. The IR spectrum of sorbent 2 maniꢀ
fests a noticeable shift of the absorption band of the carꢀ
bonyl group from 1721 to 1706 cm , which points out a
stronger complexation. The same evidence comes from
the appearance of the absorption band of the O—Cu bond
4
–
1
Sorption of copper(II) ions as a function of pH of the
solution. As can be seen from the data in Fig. 3 for sorꢀ
Table 1. Selected physicochemical properties of sorbents and monomeric analogs
Compound
рK1
рK2
SECH
+
/mmol g–1
Experiment
SECCuII
mmol g–1
/
Calculation
Sorbent 1
Sorbent 2
—
—
3.89
6.49±0.31
7.54±0.12
6.41
5.1—6.58
5.4—7.5
1.7
2.54
0.12
—
1.5
—
Anilinedipropionic
—
2
5
acid
Benzyliminodiacetic
2.24
8.90
—
—
—
2
4
acid

New sorbents with aminopropionate groups
Russ.Chem.Bull., Int.Ed., Vol. 55, No. 5, May, 2006
831
Table 2. Wave numbers (ν) of absorption bands in the
IR spectra of sorbents 1 and 2 before (I) and after sorpꢀ
tion (II)
a/mmol g–1
a
2
.5
Sorbent
ν/cm–1
С=О
O—Cu
2.0
I
II
I
II
1
1
.5
.0
1
2
1713
1721
1714
1706
—
—
—
452
(
see Ref. 8) at 452 cm–1. These facts suggest that the
0.5
complexes based on arylaliphatic amino acid are stronger
than those on the basis of aromatic amino acid. The meꢀ
thylene bridge decreases the interaction of the aromatic
ring with a lone electron pair of the nitrogen atom of the
functional group and increases its basicity and, hence, the
5
10
15
20
t/h
a/mmol g–1
2
4
strength of a forming compound with metal ions.
Time dependence of the sorption of copper(II) ions.
b
0
.035
Equilibrium in a sorbent 1—copper(II) solution system
–
4
0.030
with continuous stirring of a 5•10 M solution of copper
sulfate is achieved within 3 h (Fig. 4, a), while periodic
stirring requires from 24 h to 3 days for equilibration. At
least 2 h of continuous stirring are necessary to equilibrate
a sorbent 2—copper(II) solution system (Fig. 4, b). The
amount of sorbed copper(II) ions decreases upon contact
of the phases for more than 3 h. The shape of the curve
0
0
0
0
.025
.020
.015
.010
(
see Fig. 4, b) indicates that copper(II) sorption on sorꢀ
0.005
2
7
bent 2 is a multistage process. It is known that on some
crosslinked polymeric sorbents transition metal ions first
add via the soꢀcalled "dangling model," when a metal ion
is attached to one functional group of the sorbent. Later
the "bridge model" can be operative when a metal ion is
bound to two functional groups from one chain or from
different macromolecular chains. In the last case, the
total amount of the metal ion retained by the sorbent
decreases. The multistage character of sorption of transiꢀ
tion metal ions on complexing ionꢀexchange resins was
1
2
3
4
5
t/h
Fig. 4. Plots of the number of copper(II) ions in the phases of
sorbent 1 (a) and 2 (b) vs. time at Т = 20±2 °C.
fact that the exchange capacity for copper ions is lower
than that for hydrogen ions is a larger radius of the hydrated
copper(II) ion as compared to the radius of the hydrated
proton, which results in a worse accessibility of sorption
sites in the sorbent grain depth for copper(II) ions.
Selectivity of the sorbents. The results of studying the
sorption of cobalt(II) and nickel(II) ions on sorbent 1 at
different pH values of ammonia—acetate buffer solutions
are presented in Fig. 6.
The maximum sorption of cobalt(II) ions falls on
the pH interval 6.4—7.0, and that for nickel(II) ions lies
at pH 7.0—8.5 (see Fig. 3). Equilibration in a sorꢀ
bent 1—cobalt(II) or nickel(II) solution requires ~1.5 h;
the degree of extraction of nickel(II) is 70—75%, and that
of cobalt(II) is 60—65%. Under the same conditions, as
already mentioned, the maximum of sorption of copper(II)
ions lies in an interval of pH 5.0—6.5 and the degree of
extraction is 90—97%. The partition coefficients of
copper(II), cobalt(II), and nickel(II) ions for the maxiꢀ
mum degree of extraction of these ions on sorbent 1 are
8
mentioned in a monograph. According to published
2
data, the time needed to attain sorption equilibrium on
similar chelating sorbents (iminodiacetic acid derivatives)
with periodical stirring ranges from 3 to 30 days.
Sorption capacity for copper(II) ions. The sorption isoꢀ
therms were plotted to determine the sorption capacity.
The sorption isotherms of copper on sorbents 1 and 2 are
presented in Fig. 5. The shape of the isotherms indicates
that the surface of sorbent 1 contains energetically uniꢀ
form sorption sites and the plots show a classical shape of
the Langmuir isotherm. For sorbent 2 we obtained a
stepped isotherm, whose shape implies at least two types of
sorption sites, and its nature needs additional studies. The
static exchange capacity for copper(II) ions determined
–
1
from the sorption isotherms is 2.54 and 0.10 mmol g for
sorbents 1 and 2, respectively. A possible reason for the

832
Russ.Chem.Bull., Int.Ed., Vol. 55, No. 5, May, 2006
Neudachina et al.
a/mmol g–1
a/mmol g–1
a
0
0
0
0
0
0
0
0
0
.9
.8
.7
.6
.5
.4
.3
.2
.1
1
3
2.5
2.0
1.5
1.0
0.5
2
0
.0005 0.0010 0.0015 0.0020 CCuII/mol L–1
3
4
5
6
7
8
9
pH
a/mmol g–1
Fig. 6. Plots of the number of copper(II), cobalt(II), and nickel(II)
ions in the phase of sorbent 1 vs. pH of solutions: ammoꢀ
nia—acetate buffer solutions of copper(II) (1), cobalt(II) (2),
and nickel(II) (3) ions; t is 2 h, Т = 20±2 °C. The fraction size is
b
0
.10
.08
.06
.04
.02
0
.1—0.125 mm.
0
Thus, sorbent 1 manifests high selectivity for copper(II)
ions. The order of selectivity for sorbent 1 is Cu > Ni >
Co , which is consistent with the Irwing—Williams
series for O,Nꢀligands and with the data on selectivity of
the polymeric chelating sorbents containing residues of
iminodiacetic acid (Table 3).
In view of substantial differences in the partition coefꢀ
ficients for sorbent 1 it is possible to propose the scheme
for separation of Cu from Co and Ni controlling the
pH of the solution. At pH = 5.0 only about 20% of Co
and Ni ions introduced are extracted, whereas extraction
of Cu ions is as high as 90%. Therefore, at pH = 7.0—8.0
the sum of Cu , Co , and Ni ions can be extracted,
while pH = 5.0 is suitable for the selective extraction of
copper(II) ions.
II
II
II
>
0
0
0
1
II
II
II
II
II
II
0
.0005
0.0010
0.0015
CCuII/mol L–1
II
II
II
Fig. 5. Sorption isotherms of copper(II) ions on sorbents 1 (a)
and 2 (b) at Т = 20±2 °C.
Although the exchange capacity is low (see Table 1),
II
II
2
8.4, 2.0, and 2.4, respectively. Sorbent 2 does not virtuꢀ
the absence of sorption of Co and Ni ions on sorbent 2
ally sorb cobalt(II) and nickel(II) ions.
allows us to propose this sorbent for selective extraction
Table 3. Selectivity patterns for chelating sorbents1
Sorbent
Matrix*
Functional
Order
analytical group
of selectivity
V
Chelexꢀ100
PSꢀDVB
—CH N(CH COOH)
Hg > UVI > Cu > V > Pb > Ni >
2
2
2
Cd > Zn > Co > FeII > Mn
II
>
>
>
Be > Ca > Mg > Ba
II
III
III
II
GMA—EDMA—IDAA
Copolymer of glycidyl methacrylate —N(CH COOH)
Cu > Fe > Co > AlIII > Ni
>
2
2
II
I
II
II
VI
II
with ethylenedimethacrylate
> Mn > Ag > Zn > Pb > U
II
II
II
II
ANKBꢀ2
Dowex Aꢀ1
PSꢀDVB
PSꢀDVB
—CH N(CH COOH)
Cu > Ni > Co > Zn > Mn
2
2
2
2
III
II
—CH N(CH COOH)
Cr > FeIII >PdII > CuII > Hg
>
2
2
>
NiII > Pb > Zn > Co
II
II
II
*
PSꢀDVB is the copolymer of styrene and divinylbenzene.

New sorbents with aminopropionate groups
Russ.Chem.Bull., Int.Ed., Vol. 55, No. 5, May, 2006
833
of copper(II) ions. Sorbents with a low exchange capacity
solution. The pH value was monitored on an EVꢀ74 ionometer
equipped with glass (ESLꢀ43ꢀ07) and saturated Ag/AgCl
–
1
(
0.01—0.1 mmol g ) and a small grain size (grain diamꢀ
(
EVLꢀ1M3.1) electrodes at 20±1 °C and the ionic strength of
eter less than 20 µm) find wide use for the preparation of
–
1
2
8
the solution µ = 0.1 mol L (KCl). Standard buffer solutions
were used for calibration of the ionomer, and a carbonateꢀfree
solution of potassium hydroxide was used as the titrant.
columns in ion chromatography. These characteristics
of the sorbent make it possible to extract copper(II) ions
from fairly dilute solutions, and a small volume of the
eluate can be used for elution.
Sorbents were synthesized by the method of polymerꢀanaloꢀ
gous transformations and identified by elemental analysis and
IR spectroscopy at the Laboratory of Oligomers of the Institute
of Organic Synthesis (Ural Branch of the Russian Academy of
Sciences). Diffuse reflectance IR spectra were obtained on a
Perkin—Elmer SpectrumꢀOne spectrometer. Elemental analyꢀ
sis was carried out on a Perkin—Elmer automated analyzer.
Synthesis of sorbent 1. Nitration of polystyrene. Finely crushed
polystyrene (5 g) was slowly added to fuming nitric acid (22 mL,
d = 1.5 g cm–3) with stirring and cooling in a water bath. A yellow
viscous solution that formed was heated for 1 h at 60 °C and
poured into 1 L of water. The resulting solid mixture was crushed
in a mortar, transferred onto a filter, washed with water to the
neutral reaction, and dried in vacuo to constant weight. The
yield was 7.5 g. Found (%): C, 60.60; H, 4.03; N, 9.57. Calcuꢀ
lated (%): C, 60.68; H, 4.81; N, 9.55. The average degree of
nitration per styrene cycle was 1.02.
Experimental
All reagents used were reagent grade. A solution of copper(II)
sulfate (0.1 mol L–1) was prepared by the dissolution of a weighed
sample of CuSO •5H O in 500 mL of distilled water. An exact
4
2
concentration of the prepared solution was determined by
complexonometric titration with ethylenediaminetetraacetic acid
disodium salt (EDTA) in the presence of the murexide indicaꢀ
2
9
–1
tor. Solutions of cobalt and nickel (1 g L ) were prepared
2
9
from pure metals (99.99%) using known procedures, and their
solutions of lower concentrations were prepared by the dissoluꢀ
tion of the initial solutions directly before experiment.
The influence of the pH of the solution and duration of
contact of the phases on the sorption of transition metal ions
II
II
II
(
Cu , Co , and Ni ) was studied and the sorption capacity was
Reduction of nitropolystyrene. Phenylhydrazine (50 mL) was
placed in a flask equipped with a stirrer, a thermometer, a conꢀ
denser, and a tube for argon supply. The flask was heated
to 200 °C. Then nitropolystyrene (2 g) was added by small porꢀ
tions at the same temperature with stirring; during this process
benzene and water were distilled off and nitropolystyrene was
dissolved. The reaction mixture was heated at 200 °C for 1 h,
and excess phenylhydrazine was distilled off in vacuo at the
temperature of the bath not higher than 200 °C (90% phenylꢀ
hydrazine were regenerated). Diethyl ether (100 mL) was poured
to the viscous mixture that formed in the same flask, and the
resulting mixture was periodically stirred until a solid mixture
was formed, which was transferred onto a paper filter and exꢀ
tracted with hot diethyl ether for 30 h. The product was dried
in vacuo and crushed in a mortar. The yield was 1.27 g.
Found (%): C, 75.80; H, 7.55; N, 12.34. Calculated (%):
C, 75.80; H, 7.41; N, 12.34. The ratio NO : NH was 3 : 7.
determined under static conditions by the method of restricted
volume with continuous stirring.2 Acidꢀbase properties of sorꢀ
bents were studied by direct potentiometric titration and using
the method of individual weighed samples.2
,3
Ionization constants of functional groups and exchange caꢀ
pacities for hydrogen ions for sorbent 1 were determined by
direct potentiometric titration with a 0.01 M solution of KOH.
After addition of each portion of the titrant, the time required to
establish a constant pH value was 30—40 min. For sorbent 2, the
ionization constants of functional groups and exchange capacity
values for hydrogen ions were determined by the method of
individual weighed samples. Weighed samples of the sorbent
(
(
0.03 g) were placed in solutions with a specified pH value
necessary pH values were set using a KOH solution) and stored
to equilibration. To control equilibration, portions of the soluꢀ
tion above the sorbent were taken periodically and the pH was
measured.
2
2
Carboxyethylation of aminopolystyrene. A mixture of aminoꢀ
polystyrene (5 g) and acrylic acid (14 mL) was heated with
stirring in a water bath for 5 h, cooled, filtered, and washed with
water on the filter to the neutral reaction. The solid residue was
transferred back to the flask, and potassium hydroxide (6 g) and
distilled water (25 mL) were added. The mixture was boiled for
15 min. Then the contents of the flask was placed on a filter and
washed with water to the neutral reaction. The product was
dried in vacuo. The yield was 5.05 g. Found (%): C, 43.21;
H, 5.98; N, 4.34. Calculated (%): C, 43.20; H, 5.98; N, 4.35.
Two carboxyl groups fall per amino group (degree of carboxyꢀ
ethylation).
The dependence of the sorption of transition metal ions
II
II
II
(
Cu , Co , and Ni ) on pH of the solution was studied
under static conditions by the method of restricted volume
with continuous stirring. Solutions with the concentration
–
4
–1
n•10
pH 3.0—9.0. Specifically acetate (pH 3.2), ammonia—acetate
pH 3.5—8.0), and ammonia (pH 8.5—9.0) buffer solutions were
applied.
Sorption isotherms were obtained under static conditions
mol L were used for sorption in the interval of
(
with continuous stirring for 3.5 h (sorbent 1) and 2 h (sorbent 2)
at pH 6.0—7.0 from solutions with the content of copper(II) ions
–
4
–3
–1
–1
from 1.0•10 to 2.5•10 mol L . The amount of the sorbed
metal ion was determined from the difference of concentrations
of copper(II) ions in the solution above the sorbent before and
after sorption.
IR spectrum of sorbent 1, ν/cm : 2700—2900 (N—H); 1715
–
–
31
(C=O); 1600 (COO ); 1370 (COO ); 1330 (N—H).
Prior to work the sorbent was transformed into the H+ form
with a 0.1 M solution of HCl followed by washing with water to
The concentration of metal ions in the solution above the
sorbent before and after sorption was determined by spectroꢀ
photometry using 4ꢀ(2ꢀpyridylazo)resorcinol.30 The absorbance
of solutions was measured on an SFꢀ26 spectrophotometer at
λmax = 495 nm and l = 1.0 cm, using a blank entry as a reference
remove chloride ions (test with AgNO ).
3
Synthesis of sorbent 2. Preparation of iminodipropionitrile.
A 75% aqueous solution of ammonia (18.8 mL) was added to
acrilonitrile (33.25 mL). The reaction mixture was stirred and
left to stand for 1 day. Then the twoꢀphase liquid was distilled

834
Russ.Chem.Bull., Int.Ed., Vol. 55, No. 5, May, 2006
Neudachina et al.
in vacuo, and the fraction with b.p. 165 °C (160 Torr) was
collected. The yield was 13.3 g.
8. K. M. Saldadze and V. D. KopylovaꢀValova, Kompleksoꢀ
obrazuyushchie ionity [Complexation IonꢀExchange Resins],
Khimiya, Moscow, 1980, 335 pp. (in Russian).
9. A. A. Vshivkov, L. K. Neudachina, and V. P. Melkozerov, in
Khimiya (Programma "Universitety Rossii»") [Chemistry (Proꢀ
gram "University of Russia")], Mosk. Gos. Univ., Moscow,
1994, 96 (in Russian).
10. D. Braun, Khimiya i tekhnologiya polimerov [Chemistry and
Technology of Polymers], 1961, Issue 6, 66 (Russ. Transl.).
11. M. Kucharski, Polymery, 1966, 11, 251.
Synthesis of dimethyl iminodipropionate hydrochloride.
Methanol (89.65 mL) and iminodipropionitrile (12.3 g) were
placed in a flask equipped with a mechanical stirrer and a dropꢀ
ping funnel. The mixture was cooled down to 15 °C, and thionyl
chloride (28.8 mL) was added with such a rate that the temperaꢀ
ture of the reaction mixture would not exceed 15—20 °C. After
the whole portion of thionyl chloride was added, the reaction
mixture was stored at the same temperature for 18 h and then
heated to boiling and kept boiling for 1.5 h. After 1 day, the
reaction mixture was heated again, and a precipitate of ammoꢀ
nium chloride that formed was filtered off from the hot solution.
The filtrate was cooled down, and methanol was distilled off
in vacuo. The residue was dried in vacuo to constant weight. The
yield was 16.27 g.
12. H. Zenftman, J. Chem. Soc., 1950, 982.
13. V. G. Sinyavskii, M. Ya. Romankevich, and N. P.
Tsygankova, in Metody polucheniya khimicheskikh reaktivov i
preparatov [Methods for Preparation of Chemical Reagents],
IREA, Moscow, 1964, Issue 9, 17 (in Russian).
14. R. V. Davies, J. Kennedy, E. S. Lane, and J. L. Willans,
J. Appl. Chem., 1959, 9, 368.
Introduction of fragments of methyliminodipropionic acid.
A mixture of the chloromethylated styrene copolymer with 2%
15. G. B. Bachman, H. Hellmar, K. R. Robinson, R. W. Finholt,
E. J. Kahler, L. J. Fillar, L. V. Heisey, L. L. Lewis, and
D. D. Micucci, J. Org. Chem., 1947, 12, 108.
pꢀdivinylbenzene (chlorine content 1.0—1.1 mgꢀequiv g–
1
)
(
9.5 g), dimethyl iminodipropionate hydrochloride (8.135 g),
and a solution of metallic sodium (0.85 g) in methanol (15 mL)
was stored for 15 h on boiling (temperature 70 °C) in a water
bath. The product was cooled down, filtered, and washed with
methanol (200 mL). Methanol (12 mL), water (12 mL), and
NaOH (2.9 g) were added to the grafted product, and the mixꢀ
ture was heated for 5 h at 55 °C. The obtained polymer was
washed with water, 5% HCl (to pH < 7), and water again to
16. H. Seliger, Makromol. Chem., 1973, 169, 83.
17. US Pat. 2195974; Chem. Abstrs, 1940, 34, 5093 .
18. GB Pat. 478304; Chem. Abstrs, 1938, 32, 4610 .
19. E. B. Trostyanskaya and G. Z. Nefedova, Zh. Anal. Khim.,
1962, 17, 411 [J. Anal. Chem. USSR, 1962, 17, 400 (Engl.
Transl.)].
20. Author´s Certificate 608799 USSR; Byul. izobret. [Invention
Bulletin], 1978, 20 (in Russian).
7
1
remove chloride ions (test with AgNO ). The sorbent was dried
3
at 60 °C. The yield was 9.8 g. Found (%): C, 83.61; H, 7.88;
N, 1.01. Calculated (%): C, 83.31; H, 7.81; N, 1.09.
IR spectrum of sorbent 2, ν/cm–1: 1722 (C=O).
21. Author´s Certificate 645358 USSR; Byul. izobret. [Invention
Bulletin], 1981, 26 (in Russian).
22. US Pat. 4055586; Chem. Abstrs, 1977, 87, 24212t.
31
2
3. US Pat. 3899472; Chem. Abstrs, 1975, 83, 114436r.
This work was financially supported by the Ministry
of Education and Science of the Russian Federation
24. N. M. Dyatlova, V. Ya. Temkina, and I. D. Kolpakova,
Kompleksony [Complexones], Khimiya, Moscow, 1970,
417 pp. (in Russian).
(
Scientific Program "Universities of Russia," Grant
2
5. V. P. Melkozerov, L. K. Neudachina, and A. A. Vshivkov,
Zh. Obshch. Khim., 1997, 67, 99 [Russ. J. Gen. Chem., 1997,
UR.05.01.438) and the Ural Scientific Educational
Center "Promising Materials" (Grant CRDF RECꢀ005,
EKꢀ005ꢀХ1).
6
7, 92 (Engl. Transl.)].
2
6. Yu. A. Skorik, L. K. Neudachina, A. A. Vshivkov, Yu. G.
Yatluk, and N. V. Gert, Zh. Fiz. Khim., 1999, 73, 2269 [Russ.
J. Phys. Chem., 1999, 73, 2055 (Engl. Transl.)].
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2
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. W. Rieman and H. Walton, Ion Exchange in Analytical Chemꢀ
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6
1
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erence Book], Khimiya, Moscow, 1979, 320 pp. (in Russian).
Received January 10, 2006;
in revised form April 17, 2006