副品红的合成、提纯及生产废水处理工艺改进

Synthesis and purification of parafuchsin and improvement of production wastewater treatment process

摘要:

采用两步催化法合成副品红，首先以对硝基甲苯为起始物料，与多硫化钠在乙醇为有机溶剂、N,N-二甲基乙酰胺（DMA）为胺基催化剂条件下生成对氨基苯甲醛，结果表明，n（DMA）: n（对硝基甲苯）=3:13反应效果最佳；然后，在醇基催化剂聚乙二醇400（PEG-400）催化下与苯胺和盐酸反应生成副品红粗品，考察物料比、反应温度和反应时间对副品红粗品产率的影响，结果表明，n（PEG-400）: n（对硝基甲苯）=2:300、n（对硝基甲苯）: n（苯胺）: n（盐酸）= 1: 5.9: 2.8、在110 ℃下反应4 h，副品红粗品产率为85.6%。在副品红提纯工艺中，考察蒸馏温度和时间对副品红质量分数的影响，结果表明，在130 ℃下蒸馏3 h，副品红的质量分数达到99.3%。副品红生产废水主要为苯胺，精馏后苯胺回收率达89.3%。该工艺具有绿色、高效、环保的特点，有利于工业化推广。

Abstract:

Parafuchsin was synthesized by a two-step catalytic method. Firstly, para-nitrotoluene was used as the starting material, and sodium polysulfide was combined with ethanol as the organic solvent and N, N-dimethylacetamide(DMA) as the amine catalyst. The results showed that n (DMA) : n (p-nitrotoluene) =3:13 reaction effect was the best. Then, under the catalyst of alcohol based catalyst polyethylene glycol 400 (PEG-400), it reacted with aniline and hydrochloric acid to produce para-magenta crude product. The effects of material ratio, reaction temperature and reaction time on the yield of para-magenta crude product were investigated. The results showed that n (PEG-400) : n (p-nitrotoluene) =2: 300, n (p-nitrotoluene) : n (aniline) : n (hydrochloric acid) = 1: 5.9:2.8, reaction at 110 ℃ for 4 h, the yield of para-magenta crude was 85.6% .In the process of parafuchsin purification, the effects of reaction temperature and time on the mass fraction of parafuchsin were investigated, The results showed that the mass fraction of parafuchsin reached 99.3% after reaction at 130℃ for 3h. The wastewater from parafuchsin production is mainly aniline. After rectification, 89.3% of aniline can be recovered. The process has the characteristics of green, high efficiency and environmental protection, and is conducive to industrial popularization.