SU632690A1 - Method of obtaining c7-c9-alkylhydroxamic acid - Google Patents

Description

I

The invention relates to an improved method for the preparation of cOiKHjjrHflpOKcaMOBHx acids, which find use as flotation reagents.

The patent and technical literature widely describes various methods for the preparation of alkyl hydrokeamic acids by the interaction of carboxylic acid esters with hydroxyl amine in the presence of caustic alkali and surfactants lj.

The closest to the described method by technical ingenuity and the achieved result is the method of obtaining Cb – alkyl hydroxamic acids, which is due to the fact that the esters of carboxylic acids of the C СУ – C9 fraction are reacted with 1b – 40% aqueous solution of salt ( In the presence of a substance, for example OP-10, an aqueous solution of sodium hydroxide and a 10% aqueous solution of sodium sulfide, taken in a twofold excess, are compared with that calculated by the reaction, in the presence of a substance, for example OP-10, in the presence of HocTHo-ciKTHBHoro. Yield 80-88% 23,

However, if the introduction of sulfide in the atmosphere makes it possible to stabilize

2

the known process, it is necessary to strictly observe the pH value at the dosage of sodium sulfide, since at pH lower than 7 its decomposition begins with release of hydrogen sulphide, and at pH higher than 7 it does not give the desired effect.

In addition, sodium sulphide is a toxic product capable of causing burns, its use leads to the release of hydrogen sulphide, which improves hygiene and hygiene.

 process characteristics and complicates waste gas disposal. All this

§ complicates the process ..

The aim of the invention is to simplify the process.

The goal is achieved

the described method for the preparation of C-j-C-alkylhydroxamic acids, which consists in the fact that the esters of the corresponding carboxylic acids

: is reacted with an aqueous solution of a hydroxylamine salt in the presence of surfactants and elemental sulfur, used as a solution in hydroxide

;on three . The amount of ceI used is 0.01-0.05 mol per

Claims (2)

i1 mol of the starting carboxylic ester. The desired product was settled by settling, yield 90%. A 4-liter YrimertsV quadrupole flask equipped with a stirrer, a thermometer and an addition funnel was charged with 700 ml (910 g) of a 15.1% solution of technical hydroxyalgensulphate containing 30.5% ammonium sulphate, 10.5% of sulfuric acid and 0.02% iron ibnov, 186 ml (163.6 g) of methyl ester of carboxylic acids of the Cf and Ca fractions and 17 g of the auxiliary substance OP-10. At a temperature of 20–25 ° C, 505 ml (750 g) of 45% sodium hydroxide is poured in which 0.5–1.0 g of elemental sulfur is preliminarily dissolved. After two hours of aging at 25–27 € and pershlivanie, 500 ml of water and 132 ml (242 g) of 92% sulfuric acid (up to pH 3). The temperature should not exceed140 ° C. After half an hour of settling, 199 g of an oil layer containing 74% alkylhydroxamic acid is separated. and 10% carboxylic acids. You move alkylhydroxamic acids, considered not; carboxylic acid methyl esters, 90%. The process according to the invention makes it possible to produce alkylhydroxamic acids under industrial conditions in a yield of about 90% and in high quality. This simplifies the process management, improves the sanitary and hygienic state of production, in addition, the production of alkylhydroxamic acids by this method can be carried out by continuous technology. The method of obtaining Su-C-alkyl hydroxamic acids by the interaction of esters of the corresponding carboxylic acids with an aqueous solution of a hydroxy-1 salt in the presence of surfactants and an aqueous solution of sodium hydroxide, characterized in that, in order to simplify the process, in the presence of elemental sulfur in the amount of 0.01; 0.05 mole per mole of the starting carboxylic acid ester. Sources of information taken into consideration during the examination; 1. Authors certificate. 3,90074, cl. C 07 S 83/08, L4.08.7b. 2. Shchukin N.E. et al., Improvement of the IM-50 flotation reagent process. Journal of Applied Chemistry, 1976, v. 49, c. .3, p. 638-640.