HMCM-22分子筛负载磷钨酸催化合成聚甲醛二甲醚

摘要

In order to increase the acidity of HMCM-22 catalyst and its catalytic performance for synthesizing of polyoxymethylene dimethyl ethers (DMMn), the acidity of HMCM-22 was enhanced by the method of loading phosphotungstic acid (PW) on it. Over the obtained PW/HMCM-22 catalyst, the synthesis of DMMn was studied by using methanol and trioxane as raw materials. The effect of the loading amount of PW, the calcining temperature and the calcining time on the catalytic performance were also investigated. The results show that the optimal preparation conditions are the mass loading amount of catalyst of 30%, the calcining temperature of 300 ℃ and the calcining time of 4 h. A higher catalytic activity of PW/HMCM-22 can be achieved under the optimal preparation conditions, and the conversion of trioxane and the selectivity of DMM2-8 are 87.12%and 54.84%respectively. After reusing five times, the catalytic performance of the catalyst has only little change, which indicates that the stability of the catalyst is perfect.%为提高HMCM-22催化剂的酸性，增强其催化聚甲醛二甲醚(DMMn)合成反应活性，通过在HMCM-22分子筛上负载磷钨酸（PW）来增强HMCM-22催化剂的酸性，并以制得的PW/HMCM-22为催化剂，甲醇和三聚甲醛为原料，对聚甲醛二甲醚的合成反应进行了研究。考察了磷钨酸的负载量、焙烧温度和焙烧时间对催化性能的影响。结果表明，当磷钨酸负载量为总催化剂质量的30%，焙烧温度为300℃，焙烧时间为4 h的条件下，PW/HMCM-22催化剂的催化活性较高，三聚甲醛转化率和DMM2~8选择性分别达到了87.12%和54.84%。催化剂循环使用五次后，其活性基本没变化，表明该催化剂的稳定性能很好。