SU1087534A1 - Process for preparing water-soluble polyelectrolyte - Google Patents

Abstract

A method for producing a water-soluble polyelectrool by polymerizing (meth) acrylic acid in the presence of ammonium carbonate and a radical type initiator by heating, characterized in that, in order to improve the flocculating and structure-forming properties of the polyelectrolyte, sodium hydrogen carbonate and an polymerase and an polymerase will additionally inject into the mixture and an polymerase and polymerization properties of the polyelectrolyte. at a molar ratio of (meth) acrylic acid, ammonium carbonate and sodium bicarbonate, equal to 1-4: 1-2: 1, respectively.

Description

about

00

The invention relates to a method for the treatment of water-soluble acrylic acid-based polyelectrolytes of nitrogen-containing compounds and can be used in the synthesis of dry powder-like water-soluble polyelectrolytes with various hydrophilic functional groups, and the resulting polyelectrolytes can be used in hydrometallurg and protecting the biospheres during cleaning of wetting chemicals. known waters of metallurgical production. A known method for producing a water-soluble polyelectrolyte, conventionally called SMMA (Na) j, by polymerization of methacrylic acid in the presence of urea and sodium bicarbonate in bulk for 1 hour with a low yield up to 80% 1 X. . The disadvantages of the method include high reaction temperature 90 and low flocculation properties. The closest to the invention in its technical nature is a method for producing a water-soluble polyelectrolyte, conventionally called PAH, by polymerizing acrylic acid in the presence of ammonium carbonate and hydrogen peroxide as an initiator. According to the method, the polymerization of acrylic acid and ammonium carbonate is carried out in a mass in one stage at HC-SO in the presence of hydrogen peroxide 0.5-0.9% to acrylic acid for 30 minutes. However, the polyelectrolyte obtained does not have sufficiently high flocculating and structure-forming properties. The aim of the invention is to improve the flocculating and structure-forming properties of polyelectrolyte. To achieve this goal, according to the method of obtaining a water-soluble polyelectrolyte by polymerizing (meth) acrylic acid in the presence of ammonium carbonate and radical type initiator, the sodium bicarbonate is additionally introduced into the reaction mixture and the polymerization is precipitated; molar ratio of methacrylic acid and carbonate is added ammonium and sodium bicarbonate, 1-4: 1-2: 1 respectively. These reaction conditions, the ratio of monomers and the polymerization of acrylic acid and ammonium carbonate they are in sodium bicarbonate medium, they allow the reaction temperature to be reduced to 40-50, the reaction time is halved compared to the known method, and the content of carboxylate and amide groups in the macromolecule chain is increased compared to the carboxyl group. The proposed polyelectrolyte is conventionally named: PAUS. PAUS polyelectrolytes dissolve well in water, the intrinsic viscosity of CtJs determined in 1.3% NaCl solution in PAUS is 5.48 (higher than that of the known PAH 4.32). Aqueous solutions of PAUS and PAHs conduct electric current: the specific electrical conductivity of 0.5% aqueous solutions for PAUS is 18.4. 10, whereas in PLU 7.8.10 Omsm. High flocculating. the properties of the wastewater treatment of metallurgical production are achieved; due to the combination of functional groups and improved X properties of aqueous solutions. The essence of the method for producing a water-soluble polyelectrolyte is as follows. The calculated amounts of acrylic (methacrylic) acid are mixed and ammonium carbonate is mixed thoroughly, hydrogen peroxide and sodium hydrogen carbonate are added. This mixture is left at 40-50 ° C, stirring occasionally, and for 10 minutes, bournum polymerization of acrylic acid occurs with simultaneous replacement of the carboxyl groups by ammonium carbonate and sodium hydrogen carbonate. As a result, the reaction temperature spontaneously rises to 120-14 ° C with the release of water vapor, carbon dioxide and minor amounts of ammonia, which favors the formation of protective groups in the macromolecule chain. At the end of the reaction, a porous product is obtained, which upon cooling is very easily crushed into powder. Example 1. In a glass with a thermometer and a stirrer, 72 g of 1 mol) of acrylic (87 g, 1 mol, ethacrylic) acid, 45 g (0.5 mol) of ammonium carbonate are placed, the mixture is thoroughly mixed, then 21 g (0, 25 mol of sodium bicarbonate, 0.11 g of hydrogen peroxide (33%) and leave this mass at 40-50 s, occasionally stirring. Within 10 minutes, a burn-in polymerization occurs with the formation of a porous product, which is easily crushed after cooling to a powder. Polymerization is accompanied by a spontaneous rise in temperature to 120-140 ° C and release of water vapor, carbon dioxide and a small amount of ammonia. Output 95-97% of theoretical. Example 2 A polyelectrolyte is prepared as in Example 1 with the exception that the amount of sodium hydrogen carbonate is 42 g (0.5 mol). Example 3. All operations are carried out in the same manner as Example 1, except that ammonium carbonate is taken in an amount of 90 g (1 mol of ammonium bicarbonate — 84 g (1 mol). Example 4. In analogy to Example 1, except that acrylic 36 g (0.5 mol) is taken in the amount of ammonium, 90 g (1 mol) of ammonium carbonate and 42 g (0.5 mol) of ammonium bicarbonate. The effective flocculating effect of the proposed polyelectrolyte is established when it is introduced into the steelmaking and rolling mills of metallurgical plants. For comparison, take the well-known PAH and b Zonal polyacrylamide - PAL. The effectiveness data is given in Table 1, which indicates the time (min) for which there was a decrease in the concentrations of suspended solids from the initial 3.5 kg / m to a permissible concentration of 0.075 KG / M- (75 mg / l) at treatment of steelmaking and rolling plants of metallurgical enterprises Table 1

The data show that the efficiency of the proposed PAUS in comparison with the CMMACNa analogue of the known PAH and base PAA is 1.3-1 times more. So, for example, at a dose of 0.5 mg / l, PAUS reaches the permissible concentration of suspended solids in 25 minutes of settling, during the same time, permissible concentration is achieved using PAA, but already at a higher dose — 0.7 mg / l, and PAH is consumed 1.0 mg / l and SMMA (Na) is also 1.0 mg / l, therefore, the consumption of the proposed PAUS is 1.5-2 times less than the analog of the SMMA (Na), known PAH and base PAA. The proposed polyelectrolyte, as well as the well-known and basic PAA, has structure-forming properties when introduced into the soil dispersion. Thus, when introduced into the soil, the proposed polyelectrolyte forms a larger number of water-resistant soil aggregates larger than 0.25 mm in diameter compared with the known and basic PAA. The number of water-resistant soil aggregates is

510875346

the main characteristic of the process on the formation of water-resistant soil structure formation in soils.

Effect of dose and type of polyelectrolytes

As can be seen from the data table. 2 in terms of structure-forming ability, the proposed polyelectrolyte is superior to the known and basic PAA at various doses by 4–14%, which indicates the effectiveness of the proposed polyelectrolyte.

aggregates of typical sierozem are given in table. 2

table 2

The advantage of the proposed method over the known method is the possibility of obtaining polyelectrolyte in the form of a friable, porous, easily comminuted mass. In addition, the proposed polyelectrolyte is non-hygroscopic.

Claims (1)

METHOD FOR PRODUCING A WATER-SOLUBLE POLYELECTROLYTE by polymerizing (meth) acrylic acid in the presence of ammonium carbonate and a radical type initiator by heating, characterized in that, in order to improve the flocculating and structure-forming properties of the polyelectrolyte, sodium bicarbonate is additionally introduced into the reaction mixture and polymerization is carried out. at a molar ratio of (meth) acrylic acid, ammonium carbonate and sodium bicarbonate, equal to 1-4: 1-2: 1, respectively. _o ω c {wa · ^ ABOUT Q0 h SL 1087534 ί