SU64046A1 - Method of cleaning comenamic acid - Google Patents

Description

Comenaminic acid (3,4-dioxy-pico. Tonic acid) can be obtained either by heating b-bromo-comenic acid with ammonia to 150 or by boiling with an excess of ammonia meconic or comenic acid. The last of these methods is the most important, since Komenova (5-hydroxy-4-pyrone-2-carboxylic) acid is a technical product, easily obtained from opium production waste (meconates). But in its implementation, the co-product becomes strongly tarred, and to obtain colorless crystals of comenamic acid one has to cross it over and overlap it in the presence of coal.

The author of the present invention proposes to purify comenamic acid, obtained by aminating comenic acid, by acidifying the reaction product with hydrochloric acid, treating with coal, then filtering the south solution by evaporation. One stripped off solution is neutralized by heating with caustic sodium, cooled, and the crystalline precipitate of Kamenovo acid is separated.

Example. A solution of 140 g of the ammonium salt of Kamenovo acid in

1.4 liters of water and 280 ml of a 22-percent ammonia are heated in a flask with a direct cooler fitted with a trap and a receiver. Heating is carried out in an oil bath heated to 100-120, while ammonia water is distilled off. After two hours, the sludge is poured back into the reaction flask, and 70 ml of 22 g of 1 g of gum is added to the same. After three such transfusions, the sample from the trap is acidified to acidic reaction to the congo and, if ethol precipitates a bronze-colored precipitate, which gives a blue-violet staining with ferric chloride, the process is terminated.

In total, heating lasts 10–12 hours, after which 420 ml of hydrochloric acid (sp. 1.19) is added to an additional warm reaction mass, heated to boiling and filtered through a filter. The filtrate is treated with carbon to decolorize the solution. The solution is evaporated to a residue in the initial volume. At 60-70, 400 ml of a 30% aqueous solution of sodium hydroxide are slowly added to the evaporated filtrate, cooled, and precipitated crystals. filtered off. No. 64046-2 -

The yield is 78 g, which is in a diluted solution, about 62% of the theoretically possible, characterized in that the product

The melting point of 260-263 ° C is acidified by hydrochloric acid degradation. A lot of acidic solution is purified.

, -, - cornered, filtered solution

PRIORITY AND 3 ABOUT 6 N and they thicken, neutralize at heat. The method of cleaning comenamine refining with caustic sodium R after-,

acid received by; Amini-cooling separates crystalline ammonium and carbonic acid ammonium sludge.