SU432137A1 - METHOD OF OBTAINING 1,2-NAFTOHINON-5-SULFURA ACETE PLANT: ^ W 3 3 ^ ME'gTy \ g.,. , - Google Patents

Description

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The invention relates to a new method of producing 1,2-naphthoquinone-5-sulfonic acid, used as a raw material for the production of 1,2-naphthoquinone-5-sulfonyl chloride and its corresponding diazides.

A known method for producing 1,2-naphthoquinone 5-sulfonic acid is that 2-hydroxynaphthalene-5-sulfonic acid is combined with diazotized aniline, the resulting azo compound is reduced with tin in hydrochloric acid, the resulting amino-naphthol sulfonic acid is oxidized by a nitric acid to a nitric acid in a hydrochloric acid, and the resulting nitric acid is oxidized with a nitric acid to a nitric acid and an acid to a nitric acid in a hydrochloric acid; The known method is multistage, in addition it is necessary to work with carcinogenic p-naphthylamine, which is the starting product for the synthesis of 2-hydroxynaphthalene-5-sulfonic acid.

A new method is proposed for the preparation of 1,2-naphthoquinone-5-sulfonic acid by oxidation of 1-hydroxy naphthalene-5-sulfonic acid with an aqueous solution of potassium nitrosodisulfonate.

The method consists in mixing the aqueous solution of 1-hydroxynaphthalene-5-sulfonic acid with the reaction mixture neutralized to RP 4-8, which is obtained in the process of preparing cadmium nitrosodisulfonate, after separating it from the manganese dioxide precipitate, for 5-120 minutes keeping the pH constant in the range of 6-7, at a temperature of about -60 ° C, after which the precipitated precipitate is filtered and washed with a small amount of cold water. Dry the substance at a temperature of 20-60 ° C. The yield of 1,2-naphthoquinone-5-sulfonic acid is 75% of the theoretical, calculated on the starting 1-hydroxy naphthalene-5-sulfonic acid.

The method is simple, single-stage, and eliminates the need to work with carcinogenic p-naphthylamine.

Example. 0.84 g of sodium nitrite is dissolved in 3.6 ml of water and mixed with 6.3 ml of 5N. sodium bisulfite solution at a temperature of about -10 ° C. To the mixture is added

0.63 ml of glacial acetic acid, 1.3 ml of concentrated aqueous ammonia and 12.7 ml of 1N. potassium permanganate solution. The precipitated manganese dioxide precipitate is filtered and washed with water. Get 100 ml of the filtrate containing potassium nitrosodisulfonate. Dilute hydrochloric acid to pH 4--8 and 1.5 g of potassium dihydrogen phosphate are added to it. Solution I is prepared. 1.22 g of 1-hydroxynaphthalene-5-sulfonic acid is dissolved in 5 ml of water and 30 ml of solution I containing 1.5 g of potassium nitrosodisulfonate is added gradually with vigorous stirring. The reaction mixture is left for 30 minutes, the precipitated precipitate is filtered,

washed with water and dried at 20-60 ° C. Obtain 0.8583 g of 1,2-naphthoquinone-5-sulphelic acid; yield 75%.

The polarographic method is used to investigate the substance obtained. The polarization is carried out in a cell with a cathode and anode space divided by a porous partition. A mercury-droplet electrode is used as a cathode, and anode is a bottom mercury. A acetate buffer (pH 5.5) was used as the background. A peak at a potential of 0.09 V was obtained on the AC polarogram.

1,2-Naphthoquinone-5-sulphonic acid is identified as 1,2-naphthoquinone-2-oxime-5 sulphonic LbtH, koTra when Iron salts are added, Gives yumumrudne green, and when cobalt salts are added, a purple-red color is added.

Subject of inventions

The method of obtaining 1,2-naphthohynbn-5-у Л Л ф acid, which is distinguished by 4te, in order to simplify the process, h uxine alin 5 sulphonic acid is subjected to oxidation with an aqueous solution of potassium nitrosodisulfonate at a pH of 6-7.