连续化反应制备N,N'-双乙酰乙酰基-2,5-二甲基对苯二胺

Continuous Operation for Preparation of N,N'-bisacetoacetyl-2,5-dimethyl-1,4-phenylenediamine

以4-硝基-2,5-二甲基苯胺为原料,采用Pt/C催化加氢还原,过滤得到的溶液直接与双乙烯酮反应制备N,N'-双乙酰乙酰基-2,5-二甲基对苯二胺。考察了催化加氢的温度、氢气压力、催化剂用量和回用以及双乙酰乙酰化温度对结果的影响。实验结果:1%的Pt/C催化剂用量为4-硝基-2,5-二甲基苯胺的0.5%,氢气压力0.8 MPa,反应温度80℃,双乙酰乙酰化温度40℃,得到的产品含量98.5%,总收率95%。

An intermediate solution was prepared from 4-nitro-2,5-dimethyl aniline by Pt/C catalytic hydrogenation reduction, and N, N＇-bisacetoacetyl - 2,5 - dimethyl - 1,4 - phenylcnediamine was directly synthesized with the filtered solution and diketeneo The effects of temperature of catalytic hydrogenation, hydrogen pressure, amount of catalyst, catalyst recycling, and temperature of bis-aee- toacetylation were investigated. A proper condition was obtained by experiments： the amount of 1% Pt/C catalyst was 0. 5% of 4-nitro- 2,5-dimethylaniline in weight, hydrogen pressure was 0. 8 MPa, reaction temperature was 80 ℃ , bis-acetoacetylation temperature was 40 ℃ ; The purity of product was 98.5%, the total yield was 95%.