碳酸二甲酯作甲基化试剂催化合成对甲基苯甲醚

使用KOH／AC催化剂,考察了对甲基苯酚与碳酸二甲酯气固相催化合成对甲基苯甲醚的反应工艺条件对催化剂活性的影响。结果表明,在消除内、外扩散效应以后,随着反应温度的升高,对甲基苯甲醚的收率逐渐升高,但过高的温度会引起碳酸二甲酯分解,适宜的反应温度为607 K;改变反应压力,对甲基苯甲醚收率变化不明显;当空速为1 845 h-1,n(碳酸二甲酯)／n(对甲基苯酚)为1.5／1时,有利于对甲基苯甲醚的生成,其收率和空时收率均达到最大值。

Catalytic Synthesis of p- Methoxytoluene with Dimethyl Carbonate as Methylating Agent over KOH/AC

Catalytic synthesis of p-methoxytoluene via vapor phase reaction of p-cresol with dimethyl carbonate (DMC) over KOH activated carbon (AC) was investigated,with the aim of getting better understanding to influence of reaction parameters on catalytic activity. Yield of p-methoxytoluene increased with reaction temperature when the effects of internal diffusion and external diffusion were eliminated, but DMC would decompose at higher temperature. Reaction pressure did not showed obvious impact on synthesis of p-methoxytoluene. Suitable gaseous hourly space velocity and mole ratio of DMC to p-cresol were 1 845 h-1 and 1.5/1, respectively. Moreover, a selectivity hit 98% for p-methoxytoluene was achieved in present synthetic reaction.