CS231885B1 - Purification method of 2-hydroxy-3-<3-ureido-n-phenyl>p-naftamide - Google Patents

Abstract

The invention relates to a method of cleaning 2-Hydroxy-3- [3-ureido-N-phenyl] naphthamide, prepared by the reaction of 2-hydroxy-3-naphthoyl chloride with 3-aminophenyl urea in heterogeneous the presence of surfactants, for example alkyl polyglycol ethers. The raw product is often contaminated by-products of reaction and dyeing for refining purposes process. Previous method of cleaning by washing in 0.2% by weight hydrochloric acid it was not effective enough and did not allow obtain the product in the required quality. The process according to the invention can be reliably controlled remove the by-products of the reaction by washing in aqueous ammonia and solution ammonium salts at pH 8.5 to 10 under action surfactants such as alkyl polyglycol ethers, at 80-100 ° C, filtering and washing the product.

Description

The present invention relates to a process for the purification of 2-hydroxy-3- (3-ureldo-N-phenyl) -naphthamide.

The present method of purification of 2-hydroxy-3- (3-ureido-N-phenyl) -naphthalide by washing in 0.2% hydrochloric acid, filtration and washing with water has not been effective and did not remove the accompanying impurities from the synthesis of crude product of dyeing quality the blank was not suitable.

These disadvantages are eliminated by a method of purification of 2-hydroxy-3- / 3-ureido-phenyl-N / naphthamide technical type disperser, in the presence of nonionic detergents such as alkyl polyglycol ethers such as ethylene condensates Ig ^H 37- ^C / ^O- C ^H 2 ^-CH 2 ^{/ R2} O ^OH 'which is the subject of the invention whose principle consists in that the cleaning is done in an aqueous ammonia environment in which may be optionally replaced Some ammonia ammonium salt such as chloride, sulphate or carbonate at a pH of 8.5 to 10 and a temperature of 80 to 100 ° C, followed by stirring the reaction mixture, filtering and washing the product.

The following examples illustrate the process without limiting the scope of the invention.

Example 1

1200 l of water are introduced into the enameling boiler with stirring, 120 kg of crude 2-hydroxy-3- (3-ureido-N-phenyl) -naphthamide are introduced in the form of a 40% aqueous paste, 20 l of 25% ammonia water are allowed. % alkyl polyglycol ether and 6 kg of C ₁₈ H ₃₇ - / O-CH ₂ -CH ₂ / _2O -OH.

The boiler is sealed, the reaction mixture is heated to 85 ° C and kept at this temperature for 2 hours, then filtered on a filter press and washed with 400 L of 60 ° C warm water.

110 kg of 2-hydroxy-3- (3-ureido-N-phenyl) -naphthamide pure 100% are obtained.

Example 2

The second exemplary embodiment of the invention is similar to the first exemplary embodiment except that 15 l of 25% by weight ammonia water is used instead of 20 l of 25% by weight aqueous ammonia together with the addition of 3 kg of ammonium chloride and with the difference that the purification is performed instead of at 85 ° C at 90 ° C.

Claims (1)

Process for the purification of 2-hydroxy-3- (3-ureido-N-phenyl) -naphthamide in the presence of nonionic surfactant-type dispersants, for example ethylene condensates such as alkyl polyglycol ether C, _o H, _- / 0-CH.-CH - / - "- 0H, characterized in that the cleaning is performed in an aqueous ammoniacal tallow / 4 4 4Ό environment in which part of the ammonia can optionally replace ammonium salts such as chloride, sulfate or carbonate at pH 8.5 to 10 and 80 to 100 ° C, followed by stirring the reaction mixture, filtering and washing the product.