Keggin结构多阴阳离子构筑高活性多酸基氧化脱硫催化剂

设计开发高活性超深度氧化脱硫催化剂是解决未来石化工业适应日益严格要求的清洁燃油标准的重要出路之一。本文合成了Keggin结构多聚铝阳离子烷基硫酸盐Al_13-SDS和磷钨酸(HPW)多阴离子构筑的催化剂HPW-Al_13-SDS(SDS=十二烷基硫酸钠),采用傅里叶红外光谱(FT-IR)、紫外可见光谱(UV-Vis)、热重分析(TG)、X射线衍射(XRD)和Brunauer-Emmett-Teller(BET)等测试手段对催化剂的结构进行表征。FT-IR和UV-Vis的表征结果表明,焙烧后的催化剂中多聚铝阳离子和HPW同时保持Keggin骨架结构。以有机硫二苯并噻吩(DBT)的正己烷溶液为模拟油品的氧化脱硫为探针反应,在选定的条件下,DBT有机硫的脱除率达到99.5%。反应后HPW-Al_13-SDS催化剂的FT-IR和XRD的表征证实产生过氧化多钨酸化合物。催化剂能够循环使用,易分离,循环使用后活性未见明显降低,是理想的模型有机硫化物氧化脱除用催化剂。

Preparation of High Activity Oxidative DesulfurizationCatalyst with Polycation and Heteropolyanion Keggin Structure

Design and development of high activity ultra-deep oxidation of desulfurization catalyst is one of the most important ways to meet the increasing stringent requirements of petrochemical industry for cleaning fuel standards in the future. Catalysts with Keggin structure aluminum hydroxide polyoxocations(Al₁₃), Al₁₃-SDS and HPW-Al₁₃-SDS(HPW=Keggin structure phosphotungstic acid, SDS=sodium dodecylsulfate) were prepared. The structures of these catalysts were characterized by Fourier transform infrared spectroscopy(FT-IR), X-ray diffraction(XRD), ultraviolet visible spectroscopy(UV-Vis), Brunauer-Emmett-Teller(BET) and thermogravimetry(TG). The preservation of the Keggin structure on HPW-Al₁₃-SDS catalyst was confirmed by IR and UV-Vis spectra. Catalytic oxidation desulfurization(ODS) reaction over HPW-Al₁₃-SDS with a model of oil(n-hexan solution of organic sulfur) was studied. In optimized condition, up to 99.5% conversion of sulfur was achieved. The efficiencies of ODS decrease from dibenzothiophene to benzothiophene. IR and XRD characterizations of HPW-Al₁₃-SDS catalyst after the reaction show that the catalysts form peroxo-tungsten complexes. The catalytic activity of the recycled HPW-Al₁₃-SDS is almost the same as freshly prepared, and can be recycled via easy separation. The catalyst used herein is an ideal model for ODS of organic sulfide.