烷基化催化剂TPD酸性表征及催化性能的动力学  

Kinetics of TPD acidity characterization and catalytic performance of alkylation catalyst

作　　者：任杰[1] 黄国文[1] 万庆梅[1] 郑妙娟[1] 

机构地区：[1]浙江工业大学化学工程与材料学院,浙江杭州310014

出　　处：《化工学报》2005年第11期2108-2113,共6页CIESC Journal

基　　金：浙江省自然科学基金项目(20010148).~~

摘　　要：通过程序升温脱附实验及其动力学模拟,对不同温度活化的催化剂进行酸性表征.表征结果表明,随着活化温度的提高,固体酸催化剂表面酸强度分布先变宽后变窄,350℃活化催化剂的强度分布最宽;催化剂表面酸强度和酸密度均呈先增大后降低、分别在350℃和250℃时达到极大值的变化规律.用催化剂失活动力学模型对烷基化反应实验数据进行模拟计算的结果表明,烷基化催化剂失活符合2级独立失活规律;随着活化温度的提高,催化剂活性先增大后降低、在250℃时为极大值,而催化剂活性稳定性具有先变差后变好、在350℃时为最差的变化规律.催化剂性能与酸性的关联显示,酸密度较大、酸强度较低的固体酸催化剂是活性稳定性较好的烷基化催化剂.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.

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 

分 类 号：O643[理学—物理化学]