杂多酸催化甲醇液相合成二甲醚

研究了杂多酸催化甲醇液相合成二甲醚(DME)的工艺,考察了反应温度、反应时间、催化剂种类及用量对甲醇转化率、DME选择性、DME收率的影响,确定了适宜的工艺条件。实验结果表明,杂多酸对甲醇液相合成DME的催化活性高低顺序为:磷钨酸>硅钨酸>磷钼酸,Hamm ett酸性滴定法测定3种杂多酸的酸强度函数范围均为-8.2～-3.7;采用磷钨酸作催化剂,甲醇液相合成DME较适宜的工艺条件为:反应温度180℃、反应时间6h、每100mL甲醇的催化剂用量3.0g。在该条件下,甲醇转化率为65.4%、DME选择性为99.8%、DME收率为32.6%。

Synthesis of Dimethyl Ether from Methanol Catalyzed by Heteropolyacid in Liquid Phase

Synthesis of dimethyl ether(DME)from methanol catalyzed by heteropolyacid in liquid phase was investigated.Effects of reaction temperature,reaction time,catalyst type and its dosage on synthesis of DME were studied.Results show that the order of catalyst activity is as follows:H3PW12O40>H3SiW12O40>H3PMo12O40.Determined Hemmett acidities of the three heteropolyacids in methanol solution are within range of-8.2～-3.7.Conversion of methanol increases with the reaction temperature and time.Under optimal reaction conditions: temperature 180℃,time 6h,catalyst dosage 3.0g per 100mL methanol and H3PW12O40 as catalyst,conversion of methanol,selectivity to DME and yield of DME can reach 65.4%,99.8% and 32.6%,respectively.