CC BY
36
Investigation of physicochemical properties of synthesized amphoteric ion exchangers
10. Rakhmatkariev, G. U. Mechanism of Adsorption of Water Vapor by Muscovite: A Model Based on Adsorption Calorimetry. Clays and Clay Minerals. 2006, 54. 423-430.
11. Mentzen, B. F., Rakhmatkariev, G. U. Localization of Water Sorbed in Barium Exchanged Zeolite Y at Several Loadings. International Neutron Centre ILL. Grenoble. Experiment # 5-22-598, August, 2003.
12. Rakhmatkariev, G. U., Isirikyan, A. A. Complete description of the adsorption isotherm by the equations of the volumetric micropore occupancy theory. Izv. AN SSSR, Ser. chem. 1988, (11), 2644-2645.
Eshkurbonov Furkat Bozorovich, Teacher Termez State University, Uzbekistan Surhondarinskaya region, Termez, E-mail: [email protected] Turaev Hayit Hudaynazarovich, Professor, Doctor of Chemistry, Dean of the Engineering Faculty of Termez State University, Uzbekistan Surhondarinskaya region, Termez, E-mail: [email protected] Jalilov Abdulahat Turapovich, Professor, Doctor of Chemistry, Director of the State Unitary Enterprise of the Tashkent Scientific Research Institute of Chemical Technology, Uzbekistan, Tashkent
E-mail: [email protected]
Investigation of physicochemical properties of synthesized amphoteric ion exchangers
Abstrast: The paper studied the process of obtaining amphoteric ion exchangers based on hydrolyzed polyacrylonitrile (GIPAN) and polyethylene polyamine (PEPA) and epichlorohydrin (EXG). The presence of hydroxyl, epoxy and amino groups in starting materials, reaction mixture and the final product was studied IR, UV spectroscopic analysis methods. When using the hydrolyzed polyacrylonitrile in a molar ratio of 1.0:1.25 exchange capacity of the ion exchanger reaches 4-4,2 mg-ekv/g. By increasing the hydrolyzed polyacrylonitrile to 2.5 m. r. resins obtained have a lower mechanical strength, but with a sufficiently high exchange capacity, up to 5.2 mg-ekv/g.
Keywords: amphoteric ion exchangers, hydrolyzed polyacrylonitrile (GIPAN), polyethylene polyamine (PEPA), epichlorohydrin (EXG), sorption, infrared spectra obtained, the epoxide groups.
Currently, one of the promising directions of the ion-exchange material is the use of reactive oligomers containing ionic groups. Using them as a starting material allows the reaction under mild conditions without using, during this reaction, the polymer analogous reactions. The use of hydrolyzed polyacrylonitrile products of interaction with nitrogen-containing compounds allows to obtain resins which are promising in the process of sorption of some metals from a variety of solutions. As is known, by reacting compounds containing an amino group with a halogen-containing compounds occurs molecular nucleophilic substitution of alkyl halides and increase the primary amine. Thus, in contrast to primary and secondary amines, tertiary amines to form quaternary salts, alkyl group attaching. Interaction with polyethylene polyamine epichlorohydrin results in the
disclosure of the stress cycle oksiaranovogo epichlorohydrin under the influence of a nucleophilic group to form chlorohydrins [1; 2]. Polycondensation of hydrolyzed polyacrylonitrile (GIPAN) and polyethylene polyamine (PEPA.) With epichlorohydrin (EXG) obtained carboxyl and nitrogen-containing oligomeric compounds. In order to identify regularities in the formation of condensate odds, we studied the effect of synthesis conditions on the condensation reaction of the hydrolyzed polyacrylonitrile and polyethylene polyamine with epichlorohydrin (the duration and temperature of reaction, ratios of starting components and others.). The temperature was varied between 80-100 °C. Thus, we investigated the change in molecular weight and intermediates forkon-densatov obtained, the concentration of epoxy groups (Table 1.).
81
Section 8. Chemistry
Table 1. - Effect of temperature on the reaction time of the polycondensation of hydrolyzed polyacrylonitrile (GIPAN) and polyethylene polyamine (PEPA) and epichlorohydrin (EXG)
Starting materials The reaction temperature, °C. The molecular weight (u. y.) The reaction time, min The content of epoxy groups,%.
EXG 20 80 - 35,4
GIPAN, PEPA, EXG 75 804 120 31,2
GIPAN, PEPA, EXG 95 1040 90 14,5
GIPAN, PEPA, EXG 105 3105 40-50 4,45
From the data ofTable 1 shows that the maximum degree of conversion observed at 90-100 °C. Therefore, the optimum temperature for the reaction took 100 °C. Increasing the reaction temperature to 90-100 °C results in a decrease in the content of epoxy groups and polycondensation reaction apparently proceeds through epoxide groups. Effect of reaction temperature on the conversion of the polymer shows that at 100 °C has the highest degree of conversion of the polymer (Figure 1).
The presence of carboxyl, epoxy and amino groups in starting materials, reaction mixture and the final product was studied IR, UV spectroscopic analysis methods. Analysis of IR spectra of the starting materials and the resulting polymer confirms the presence ofion exchanger in the structure of the active ionic groups (Figure 2.3). So on polyethylenepolyamine IR spectrum absorption bands in the region 650-900 cm-1, 3500-3000 cm-1 related to the stretching vibrations — NH2, = NH groups (Figure 2). The spectra of the resulting ampholyte also absorption bands in the region of 900-650 cm-1, 1150 cm-1 due to the variation of primary, secondary amino (Figure 3). However, the intensity of these bands is significantly reduced. In addition, in the spectra of the ion exchanger,
new bands in the region 1030-1230 cm-1, suitable stretching vibrations — N = group, which formation is due to the interaction of mobile hydrogen atoms, the secondary amino groups with the epichlorohydrin the epoxy. The presence of carboxyl and hydroxyl groups in the IR spectrum of hydrolyzed polyacrylonitrile is characterized by an absorption band in the area of 3400sm-1 and a weak absorption band at 2600-3200 cm-1 (Figure 2). The location and nature of these bands identical to those bands in the spectrum obtained by the resin, reduced only its intensity. The lack of absorption bands in the region of 30003040 cm-1 related to the stretching vibrations ofepichloro-hydrin oksiaranovogo cycle indicates that the interaction of hydrolyzed polyacrylonitrile, polyethylene polyamine with epihlorgidrnnom is due to the disclosure of epichlorohydrin oksiaranovogo cycle (Figure 3). The appearance on the IR spectrum, the reaction product of a hydrolyzed polyacrylonitrile and polyethylene polyamine with epichlorohydrin in the frequency domain 2600-2800sm-1 corresponding to the vibrations — CH2-N+ groups, indicating the formation of a quaternary ammonium salt due to the interaction ofthe chloromethyl group of epichloro-hydrin with amines polyethylenepolyamine.
80
90
100
10 20 40 60 80 Time, min
Figure 1. The dependence of the degree of conversion based polymer hydrolyzed polyacrylonitrile, polyethylene polyamine and epichlorohydrin from the length of service of the reaction at temperatures: 1-80; 2-90; 3-100 °C.
82
Investigation of physicochemical properties of synthesized amphoteric ion exchangers
Figure 3. IR spectrum of interaction hydrolyzed polyacrylonitrile, polyethylene polyamine and epichlorohydrin
Figure 4. UV spectra of the reaction product of a hydrolyzed polyacrylonitrile, polyethylene polyamine and epichlorohydrin
83
Section 8. Chemistry
The presence of the absorption band at 250 nm in the UV spectrum (Figure 4) and a reaction product GIPAN PEPA corresponding n-n* electronic transition conjugated aromatic system (phenol) [3], consistent with the infrared spectral data of a substituted benzene ring.
It was also studied the influence ofthe ratio ofthe initial components on the properties ofion exchange resins (Table 2). Table 2. - Influence of the ratio of reacting components on the properties of ion exchangers (m. r.)
Hydrolyzed polyacrylonitrile m. r. The exchange capacity of 0.1 n. HCl solution, mg-ekv/g The exchange capacity of 0.1 n. NaOH solution, mg-ekv/g Mechanical strength,%
Ion exchangers based GIPAN, PEPA, EXG (PEPA and 1m. r. 1m. r. EXG)
0,5 3,8-4,3 3,4 90,4
1,0 3,7 91,0
1,25 4,2 91,8
1,5 4,5 90,2
2,0 4,8 88,3
2,5 5,2 83,8
m. r. molar ratio.
When using the hydrolyzed polyacrylonitrile in an amount of 0,5 — m. r. observed decrease in exchange capacity compared with other relations hydrolyzed polyacrylonitrile. When using the hydrolyzed polyacrylonitrile in a molar ratio of 1,0: 1,25 exchange capacity of the ion exchanger reaches 4-4,2 mg-ekv/g. By increasing the hydrolyzed polyacrylonitrile to 2,5 m. r. resins differ low mechanical strength, but have a relatively high
exchange capacity of up to 5,2 mg-ekv/g. Therefore, the
OH
optimal ratio of the starting components for the resin-based hydrolyzed polyacrylonitrile, polyethylene polyamine, epichlorohydrin took 1,25:1:1. m. r. respectively.
Thus, on the basis of these physico-chemical and chemical research (IR, UV spectroscopy, chemical analysis, and others.) proposed structure obtained ampholytes can be represented as follows:
Ampholyte based hydrolyzed polyacrylonitrile, polyethylene polyamine and epichlorohydrin:
OH
-N-
H
H
CH
H
N
H
I H2 H2 H
-C—c —c —C-
H I
N
2 OH
H
-C---C----
H H
N
COOH
H H2 H
H
-C —C---C
Loch
H2C
2 I H2 1
---C-----C C--------N-
i H I
3
H
OOH
OH
COOH
H2 H H2 H
C —C---C —C
H C
OOCH
2
H
H2
C2
_C.
H
H
H
H
N
3
H
H
Basic properties ampholytes obtained optimum conditions are shown in Table. 3, where they are conventionally designated sleduyushego manner: ampholyte based hydrolyzed polyacrylonitrile, polyethylene polyamine and epichlorohydrin.
We carried out a detailed study of the physical and chemical properties of the ion exchangers. Main char-
COOH
acteristics of ion exchangers are presented in Table 3. Since the resins obtained have a crosslinked structure, to study their properties and structure, along with the usual chemical methods of analysis, we used the physical-chemical methods of analysis (IR, UV spectroscopy, Photocolorimeters, potentiometry, conductivity, and others.).
84
Investigation of physicochemical properties of synthesized amphoteric ion exchangers
Table 3. - Basic physical and chemical properties of the amphoteric ion exchangers
The name of indicators Humid- ity Bulk weight The specific volume of the swollen ion exchanger in water SEC of 0.1 n. solution of hydrochloric acid: The sorption capacity of ions
HCl NaOH Cu Co Ni As Ca Mg_
Unit of measurement % g/ml mg/g mg-ekv/g
GIPAN, EXG, PEPA 8,2 0,52 7,9 4,2 4,0 4,2 4,0 2,8 3,2 3,9 3,8
References:
1. Kholikov V. K., Mukhitdinova B. A., M. S. Romanov, Ergozhin E. E. The amphoteric ion exchangers based on polyvinyl benzilftalimida and some of their properties//Math. AN Kaz Ser.Him. - 1988. № 1. - S. 67-71.
2. Smokes A. N. Technical analysis. M.: Metallurgy. - 1964. - 148 p.
3. Myagoy I. O., A. I. Ryaguzova. Theory and practice of sorption processes. - M.: 1966. - S. 240-244.
85
