Y型分子筛负载磷钨酸催化剂的结构和性能

Structure and Catalytic Activity of Phosphotungstic Acid Supported on Y-Zeolite

采用混合法制备磷钨酸质量分数不同的Y型分子筛负载催化剂,利用傅立叶红外光谱和X射线衍射仪表征了催化剂的表面酸性和结构,并用催化法脱除芳烃中微量烯烃的烷基化反应考察其催化性能。结果表明,220℃焙烧的磷钨酸为Keggin结构,550℃焙烧的磷钨酸为Dawson结构,Dawson结构的磷钨酸催化烷基化反应的性能优于Keggin结构的磷钨酸。随着磷钨酸量的增加,催化剂中B酸量先增加后减少,L酸量减少。550℃焙烧的磷钨酸质量分数为5%的催化剂具有较好的催化活性和较长的寿命。

The catalysts loading phosphotungstic acid on Y-zeoliten were prepared by mixed method and charactered by Foruier transform infrared （FT-IR） and X-ray diffraction （XRD）. The catalytic activity of catalysts prepared was investgated by alkylation olefins from aromatic hydrocarbons. The results showed that the structure of phosphotungstic acid was Keggin at 220 ℃ and Dawson at 550 ℃, and the catalytic alkylation performace of Keggin was better than that of Dawson. With the increasing of the mass fraction of phosphotungstic acid, the B acid sites firstly increased then decreased and the L acid sites decreased. The catalyst containing 5% mass fraction of phosphotungstic acid and baked at 550 ℃ showed high catalytic activity and long life.