歧化反应合成对氨基苯甲醛的动力学

Kinetics of Synthesizing p-Aminobenzaldehyde by Disproportionation Reaction

用动力学方法研究对硝基甲苯(PNT)和多硫化钠(Na_2S_x)在碱性乙醇介质中形成对氨基苯甲醛(PAB)的时间进程。结果表明反应速度只与PNT浓度有关,属准一级反应;在微沸温度(83℃)及反应物PNT的起始浓度为0.304mol/L和0.152mol/L时,表观速度常数k′分别为3.32×10^(-2)min^(-1)和3.42×10^(-2)min^(-1);在最佳条件下,反应可于160min完成,转化率为94%(实际产率91%);还报道了不同条件下的转化率,为指导生产实践提供依据。

Kinetic studies showed that the reaction between p-nitrotoluene and sodium polysulfide in alkaline ethanolic medium is dependent on the concentration of p-nitrotoluene alone and the reaction is of pseudo first order with its apparent rate constants 3.32×10^(-2) min^(-1) and 3.42×10^(-2) min^(-1) when the initial concentrations of p-nitrotoluene are 0.304 mol/L and 0.152 mol/L respectively. The results also revealed that under optimum conditions, the reaction could be accomplished in 160 min with conversion ratio of 94% (actual yield 91%). Studies of synthetic reaction process by chemical kinetics would be valuable in directing manufacturing technology.