关键词: 烷基化, 固体酸催化剂, 程序升温脱附, 酸性, 催化性能, 动力学模型

Abstract: The aim of this paper is to study the surface acidity and catalytic performance of alkylation catalyst in terms of kinetics.Firstly, based on desorption kinetic model, the acidities of solid acid catalysts activated at temperature from 200 ℃ to 400 ℃ in N₂ stream were characterized through temperature programmed desorption(TPD) experiments and model parameters estimation. The catalyst acid strength was characterized with desorption activation energy which was determined by use of desorption kinetic model equation related with heating rate, temperature and overlay fraction of catalyst surface acid sites at maximum rate of desorption.The acidity characterization results indicated that the strength distribution of catalyst surface acid sites broadened firstly and then narrowed with rising catalyst activation temperature,reaching the broadest at activation temperature of 350 ℃.The acid density and acid strength of the catalyst acid sites changed from rise to drop with rising catalyst activation temperature,reaching respectively maximum at 250 ℃ and 350 ℃.Then, the reaction experimental data for alkylation of benzene with long chain olefins(C₁₀—C₁₄) in the liquid-solid reaction system were simulated by use of the kinetic model equation of catalyst deactivation.the order of catalyst independent deactivation was found to be second.The alkylation activity of catalyst changed from rise to drop with rising activation temperature and was the greatest at 250 ℃.The activity stability of catalyst changed from worse to better with rising activation temperature，and was the worst at 350 ℃.The relationship between acidity and performance of catalyst showed that the catalytic performance of the alkylation catalyst might be improved by increasing the acid density of the solid acid catalyst and decreasing the acid strength of the catalyst.

Key words: 烷基化, 固体酸催化剂, 程序升温脱附, 酸性, 催化性能, 动力学模型