Preparation method for intermediate of disperse blue 2 BLN

Abstract

The invention discloses a preparation method for an intermediate of disperse blue 2 BLN, which belongs to the technical field of fine chemical engineering. The method is as follows: sulphur is used to substitute a part of sodium sulfide; sulphur and sodium sulfide undergo an alkalization reaction at first, with alkalization temperature being 80 to 100 DEG C and alkalization time being 2 to 4 h; 1,5-dihydroxy-4,8-dinitroanthracenedione is reduced by produced Na2S2, with reduction reaction temperature being 95 DEG C and reaction time being 2 h, and a reduction product of 1,5-dihydroxy-4,8-diaminoanthracenedione is obtained. According to the invention, in preparation of the intermediate of disperse blue 2 BLN, bimolecular reduction and generation of azoxy compounds and hydrazo compounds are prevented, product purity is improved, hydrolysis of amino groups is reduced, and reaction yield is improved; meanwhile, hydrolysate of a same amount is reduced, and the number of consumed sodium sulfide molecules is decreased, thereby reducing the usage amount of sodium sulfide and production cost.

Description

technical field [0001] The invention relates to a preparation method of a disperse blue 2BLN intermediate, the chemical name of the intermediate is: 1,5 dihydroxy-4,8 diaminoanthraquinone, and the chemical formula is: , belonging to the field of fine chemical technology. Background technique [0002] At present, the process of synthesizing the intermediate 1,5 dihydroxy-4,8 diaminoanthraquinone of disperse blue in the domestic chemical dye factory is basically the same, all of which use 1,5 dihydroxy-4,8 dinitroanthraquinone as raw material. Add 1,5-dihydroxy-4,8-dinitroanthraquinone into the reduction pot, raise the temperature to 90°C, then add 18% sodium sulfide solution dropwise, control the slight excess, react to the end, cool down to 50°C, filter and Wash in a filter press until neutral, and then dry, the reaction process is shown in formula (1). But this method has the following shortcomings: [0003] ① The alkalinity is too strong in the later stage of the react...

AI Technical Summary

Problems solved by technology

[0003] ① The alkalinity is too strong in the later stage of the reaction: because Na 2 NaOH is generated after S reduction, and as the reaction progresses, OH in the medium - The concentration is gradually increased, so that the newly formed amino group undergoes hydrolysis reaction, which greatly reduces the yield. The yield of this process is only 90%.

[0005] ②Many side reactions: Aromatic amino compounds and aromatic nitro compounds undergo bimolecular reactions in the solution to form high polymers, while the hydrolysis of amino groups produces hydroxyl sodium salts that cannot be removed, and the purity of the products cannot be guaranteed