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DPA(2-甲基-4-甲氧基二苯胺)是合成压敏染料、医药、橡胶、农药和胶粘剂辅料的重要中间体。以MMA(2-甲基-4-甲氧基苯胺)和邻氯苯甲酸为原料,采用先Ullmann缩合后脱羧法制得DPA。研究结果表明:当缩合反应的催化剂为无水醋酸铜[Cu(CH_3CO_2)_2]、配体为脯氨酸、w[Cu(CH_3CO_2)_2]=6%(相对于MMA质量而言)、n(MMA)∶n(邻氯苯甲酸)∶n(K_3PO_4)=1.0∶1.3∶1.5、反应温度为130℃和反应时间为4 h时,产物的收率(为93%)相对最高;当脱羧反应的催化剂为Cu(CH_3CO_2)_2、配体为四甲基乙二胺、w[Cu(CH_3CO_2)_2]=5%(相对于2-MMA-苯甲酸质量而言)、反应温度为180℃和反应时间为6 h时,产物的收率(为92%)相对最高;上述催化剂、配体均价廉易得、分离提纯简便且环保佳,符合绿色化学生产要求。
DPA (2-methyl-4-methoxy diphenylamine) is an important intermediate for the synthesis of pressure-sensitive dyes, pharmaceuticals, rubbers, pesticides and adhesives. Using MMA (2-methyl-4-methoxyaniline) and o-chlorobenzoic acid as raw materials, DPA was prepared by Ullmann condensation followed by decarboxylation. The results show that when the catalyst of the condensation reaction is anhydrous copper acetate [Cu (CH_3CO_2) _2], the ligand is proline and w [Cu (CH_3CO_2) _2] = 6% (relative to the mass of MMA), n (MMA): n (KClPO4) = 1.0:1.3:1.5, the reaction temperature is 130 ℃ and the reaction time is 4 h, the product yield is 93% The catalyst was Cu (CH_3CO_2) _2, the ligand was tetramethylethylenediamine, w [Cu (CH_3CO_2) _2] = 5% (relative to the mass of 2-MMA-benzoic acid) and the reaction temperature was 180 ℃ And the reaction time was 6 h, the yield of the product was the highest (92%). The catalyst and the ligand were cheap and easy to get, and the separation and purification were simple and environmentally friendly, which met the requirements of green chemical production.