SU233656A1 - - Google Patents

Description

A METHOD FOR OBTAINING CRYSTALLINE ACRYLAMID.L

A known method for the preparation of crystalline acrylamide is the saponification of acrylonitrile with seric acid, neutralization with gaseous ammonia in the presence of methylene blue as an inhibitor of polymerization, subsequent separation of ammonium sulfate at a temperature of 50 ° C and a filter of the filtrate, cooling the filtrate to 0.15 ° C to isolate the desired product by the known procedure .

Get the product with iel. M. Pl. 84.5-85 ° C.

In order to obtain a product suitable for the preparation of dressing, adhesives and high molecular weight flocculants, a method is proposed for obtaining crystalline acrylamide by saponifying acrylic nitride with sulfuric acid, neutralizing it with lime to pH 8.5-9, filtering and subsequent evaporation of the mother liquor under vacuum, first with temperature 65-75 ° C, pressure 400-600 mm Hg. Art., and RP solution of 8.5-9.5, and then with a temperature of 150-110 ° C and a pressure of 600- 650 mm Hg. Art. Get the target product with so pl. 55-60 ° C.

Example. Here, 53 wt. including acrylic acid nitrile in 116 weight. h. 85 / o-th sulfuric acid; forms 169 wt. including product containing 42 ° / o acrylamine, then the resulting acrylamide sulfate is diluted with 30 wt. including water and neutralized with lime to pH 8.5-9 at a temperature not higher than 45 ° C. Plasma plaster pulp is filtered, and the mother liquor with lines of water is subjected to a two-stage process in the following equipment and in the next mode.

The first stage of evaporation is carried out in tubular evaporators under a vacuum of 400-600 mm Hg. Art. to a concentration of 45-55 / o at a temperature of 65-75 C and RP of the environment 8.5-9.5. Then, the resulting 501L. Ny product for concentration increase is evaporated in a film design of the Dzerzhinsky oil processing plant, under the following conditions:

temperature in section x of the apparatus:

in the first 150 ° C

in the second 120 ° C

in the third 110 ° C

vacuum 600-650mm Hg Art.

The melt of the acrylamide solution is crystallized on the kul-rollers and removed with a knife in the form of a cheschey product with t. 55-60 ° C.

The chemical composition of crystalline acrylamide, o / o:

acrplamsd .... 80-85 polymers .... 15-10 moisture and ir. impurities. 5 3 Leni dressing, the method of preparation of which is known and consists of the following. The dry product is diluted with water at room temperature to 7 s / s concentration in any tank, where per-5 potassium sulfate solution is supplied at the rate of 0.5 o / v to the weight of acrylamide and dry sodium hydrosulfide salt 0.14.0 / 0. The mixture is stirred and incubated for 0.5-1.5 hours. 10 The resulting thick mass is diluted 2-2.5 times to obtain a Dioxide solution, which is the finished sizing or adhesive. 4 Subject of the Invention The method of obtaining crystalline acrylamide and the saponification of acrylonitrile, neutralizing and further isolating the target product by a known technique, characterized in that the solution is evaporated under vacuum in order to obtain a dressing, adhesives and high molecular weight flocculants under vacuum, after neutralization first, when temeture 65-75 ° C, a pressure of 400-600 mm RT. Art. and the pH of the solution is 8.5-9.5, then at a temperature of 150-110 ° C and a pressure of 600-650 mm Hg. Art.