Cr_2O_7^(2-)/Cr^(3+)和Ce^(4+)/Ce^(3+)电解液作媒质间接合成对甲氧基苯甲醛

Indirect Synthesis of p-Methoxybenzaldehyde Using Cr_2O_7^(2-)/Cr^(3+ )and Ce^(4+)/Ce^(3+) as Electrolytic Medium

在高剪切混合乳化机搅拌下,通过对Cr2O72- /Cr3+和 Ce4+/Ce3+两种媒质间接合成对甲氧基苯甲醛槽外反应的研究,得到合成对甲氧基苯甲醛的优选条件分别为:原料配比n(Cr2O72-):n(p-CH3O-C6H4-CH3)=1:6,反应温度 80℃,反应时间10min,对甲氧基苯甲醛反应收率90.5%;原料配比 n(Ce4+):n(p-CH3O-C6H4-CH3)=1:1,反应温度30℃,反应时间6min,对甲氧基苯甲醛反应收率97.1%。结果表明,Ce4+/Ce3+做媒质产品时-空效率较低,这是Ce4+/Ce3+媒质存在的本质缺陷;而Cr2O72-/Cr3+做媒质产品时-空效率提高近2倍,显著地增加产品的产量,提高了经济效益。

Outside cell reactions of indirect electrosynthesis of p-methoxybenzaldehyde by using Cr2O7 /Cr3+ or Ce4+/Ce3+ as electrolytic medium in an emulsifying stirrer were studied. The optimum 2- conditions of outside cell reaction by using Cr2O7 /Cr3+ as electrolytic medium are found as 2- n(Cr2O7 ):n(p-CH3O-C6H4-CH3)=1: 6, reaction temperature 80℃ and reaction time 10min. The optimum 2- conditions of outside cell reaction by using Ce4+/Ce3+ as electrolytic medium are n(Ce4+): n(p-CH3O-C6H4-CH3)=1:1, reaction temperature 30 ℃ and reaction time 6min. Reaction yields of p-methoxybenzaldehyde are 90.5% and 97.1%, respectively. The results show that using Cr2O7 /Cr3+ as2- electrolytic medium, the yield of p-methoxybenzaldehyde in a certain space-time is 2 times higher than that of using Ce4+/Ce3+ as electrolytic medium.