SU237908A1 - METHOD OF OBTAINING NITRODAMINE "B" - Google Patents

Description

A known method for the preparation of nitrorodamin "B" by the condensation of 4-nitrophthalic anhydride with l-diethylaminophenol.

However, the yield of the target product in this case is lOf / c, the remaining 90 ° / o - 2- (2-hydroxy-4-ditylaminobenzoyl) -4 (5) is nitrobenzoic acid.

In order to increase the yield of the target product and increase its purity, the resulting substituted benzoyl benzoic acid is formed and treated with diethylaminophenol, when heated, in the presence of concentrated sulfuric acid.

Example 1. 9.65 g of 4-nitrophthalic anhydride, 8.26 g of freshly distilled g-diethylaminophenol and 50 ml of xylene are boiled for 3 hours, cooled, xylene is decanted, 8.26 g are added to the oily residue. diethylaminophenol and 30 ml of concentrated (d 1.84) sulfuric acid.

The mixture is heated at 150 ° C for 3 hours, poured into 150 ml of ice-cold distilled water and neutralized with 20 ° / V-aqueous sodium hydroxide solution (pH 6-7). The precipitate formed is separated, dried to a constant weight and extracted with 700 ml of chloroform. The chloroform extract is filtered, evaporated to volume.

300 ml II with careful stirring poured B 1.2 liters of petroleum ether (so kip. 40-60 ° C). The precipitate is separated and dried.

Yield 21.24 g (87.2 o / o). Content of the main substance 76,4Vo- Output in terms of lOOJ / 0-th product 66 ,.

Example 2. a) 19.31 g of 4-nitrophthalic anhydride, 16.52 g of freshly distilled lg-diethylamyophenol and 100 ml of benzene are heated at boiling point for 9 hours. The precipitate formed during cooling is separated and washed with chloroform. Yield of 2- (2-oxy-4-diethylam-11-benzoyl) -4 (5) -nitrobenzoic acid 13.35 g (37.2 ° / o) - 11.10 g (31.0 ° / o) acid are additionally isolated from the mother liquor.

The total yield of 2- {2-hydroxy-4-diethylaminobenzoic) -4 (5) - nitrobenzoic acid

24.45 g {68.2 o / o), m.p. 207-208.5 ° С (from acetone-chloroform). When chromatography in the system methanol - water (1: 1) on paper brand

“Slow substance gives one bright yellow spot Rf 0,860;

b) 3.58 g of 2- (2-hydroxy-4-diethylaminobenzoyl) 4 (5) -nitrobenzoic acid, 1.65 g. of i-diethylaminophenol and 20 ml of concentrated 3 for 3 hours, cooled, poured into 100 ml distilled water and neutralized with 20Vo-HHM sodium hydroxide solution (pH 6-7). The precipitated precipitate is separated; p is extracted with 150 ml of hydrochloric acid {1; 1) .5 The hydrochloric acid solution is filtered, the filter cake is washed with 70 ml of hydrochloric acid (1: 1), the filtrate is neutralized with 20 ° / NaO sodium hydroxide solution (pH 6-7). The precipitated precipitates are separated, washed with 300 ml of distilled water. 10 and dried. The output of nitrorhodamine 3.08 g (63,1o / o). The content of the main product is 93.2o / (,. Output in terms of SO / o-tional product 59, OVo. 4 P r e m u e and z oo brie n i. Method for the preparation of n-rhodamine " anhydride of Lg-diethylaminophenol followed by separation of 2- (2-hydroxy-4-diethylamino-isoyl) -4 (5) -nitrobenzoic acid precipitated as a precipitate, characterized in that, with an increase in yield and purity of the target product, the precipitate formed is treated with diethylaminophenol coli for the yield and increase in purity of the target product, the precipitate is treated with diethylaminophenol coli for the yield and purity of the target product, and the resulting precipitate is treated with diethylaminophenol colloidolol. up to 150 ° C in the presence of concentrated sulfuric acid with nosledu the selection of the target product by known techniques.