改性骨架镍催化加氢3,4-二甲基硝基苯制备3,4-二甲基苯胺

采用骤冷法制备了改性骨架镍,将其应用于3,4-二甲基硝基苯的催化加氢制备3,4-二甲基苯胺。考察了各反应参数的影响,结果表明,以甲醇为溶剂,3,4-二甲基硝基苯初始浓度1.0mol/L,催化剂质量为3,4-二甲基硝基苯质量的7%,在60℃和0.5MPa的条件下反应40min,3,4-二甲基硝基苯的转化率和3,4-二甲基苯胺的选择性均达到100%。反应过程中底物浓度与时间趋于线性关系,该反应近似表现为零级反应。反应中未检测到羟胺组分,仅有少量的亚硝基化合物以中间体形式产生,并最终完全转化为目标产物3,4-二甲基苯胺。

Catalytic Hydrogenation of 3,4-Dimethylnitrobenzene to 3,4-Dimethylaniline over Modified Skeletal Nickel

The rapid-quenching technique was introduced into the production of modified skeletal Ni catalyst,which was employed for the hydrogenation of 3,4-dimethylnitrobenzene to 3,4-dimethyl-aniline.Effects of various reaction parameters of the hydrogenation have been investigated.Under the optimized conditionsm(catalyst)/m(substract)=7% in methanol,initial concentration of the substrate=1.0 mol/L,60 ℃ and 0.5 MPa],both the conversion of 3,4-dimethylnitrobenzene and the selectivity of 3,4-dimethylaniline can be up to 100% in 40 minutes.During the reaction process,the relationship of the reactant concentration versus reaction time was linear,which suggested that it is a pseudo-zero reaction.Arylhydroxylamine,which usually exists in the hydrogenation of nitroarenes,was not found in this process.The nitroso compound was detected as the main intermediate which can completely convert to the target product.