PW_(12)/MCM-41上异丁烷/丁烯烷基化反应

Isobutane/butene alkylation over PW_(12)/MCM-41 catalyst

采用水热法制备负载型PW12 /MCM 41催化剂 ,用XRD、IR、TG DTA表征催化剂的结构、杂多酸的分散性及酸性。结果表明 :PW12 /MCM 41催化剂具有强酸性 ;在负载量高达 40 %的催化剂上 ,磷钨酸保持着Keggin结构。负载 40 %PW12 的催化剂用于异丁烷与丁烯的烷基化 ,该催化剂的酸性受活化温度影响 ,最佳温度为 2 5 0℃。超临界态下反应明显延长了催化剂寿命 。

The solid acid catalysts consisting of heteropoly acid PW 12 supported on a mesoporous molecular sieve MCM 41 were prepared by hydrothermal methods. The structure, HPA dispersive state and acidity of the catalysts were investigated by XRD,IR and TG DTA.The results show that PW 12 /MCM 41 catalysts have a high acidity and HPA can exist on MCM 41 surface and retain the Keggin unit even at HPA loadings as high as 40%. The catalyst with 40% PW 12 loadings was applied to the alkylation of isobutane and butene. It is found that the acidity of the catalyst depends on the activation temperature, the optimerized temperature of activation is about 250 ℃, and the supercritical conditions clearly prolong the catalyst's life, but the selectivity of the catalyst is unsatisfactory and in the liquid product the olefins content is still high.