烷基膦酸促进负载磷钨酸催化异丁烷/丁烯烷基化反应

异丁烷/丁烯烷基化是生产高辛烷值汽油的重要反应,目前主要采用液体强酸为催化剂,而固体催化剂用于该反应的性能均不理想。我们设计合成出十六烷基膦酸(HDPA)修饰的氧化硅负载型磷钨酸纳米多级结构催化剂(HDPA-HPW/SiO2),其结构与悬铃木果实相似。通过X射线衍射(XRD)、傅里叶变换红外光谱(FT-IR)、透射电子显微镜镜(TEM)、氮气吸附-脱附、异丁烷吸附-脱附等对该催化剂进行了表征,并使用固定床微型反应器评价了其对异丁烷/丁烯烷基化反应的催化性能。结果表明,HDPA的外围修饰增强了催化剂对烃类反应物的吸附,减少了烯烃聚合副反应和催化剂表面积碳的产生,提高了高辛烷值产物的选择性,延长了催化剂的寿命。

Isobutane/Butene Alkylation on Supported Phosphotungstic Acid Promoted by Hexadecylphosphate

The alkylation of isobutane/butene is an important reaction to produce high-octane gasoline. Replacement of liquid acid by solid acid to catalyze this reaction is the focus of the study. In this work, solid acid catalysts with hydrophobic surface were prepared by decorating hexadecylphosphate (HDPA) on SiO₂-supported heteropolyacids samples with impregnatiom method, whose structure is similar as the fruit of platanus. These catalysts were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), N₂ and i-C₄H₁₀ sorption. And the performances of the catalysts for the alkylation of isobutane/butene were evaluated using a fixed bed micro-reactor. The results show that the HDPA-modification enhances the adsorption of the hydrocarbon reactants on the surface of catalyst, which helps to reduce the polymerization of butene and to inhibit the deposition of coke on the surface of catalyst, leading to an improved selectivity of high-octane products and prolonged life of catalysts. The catalyst had an optimal catalytic performance when the HPW load was 30%(w/w) and the modified amount of HDPA is 3%(w/w).