不同方法合成的镁铝水滑石的表征及其催化原油酯化脱酸性能  

Characterization of MgAl Hydrotalcites Prepared by Various Methods and Their Catalytic Activities for Esterification to Remove Acid From Crude Oil

作　　者：吴雁[1] 王豪[1] 钟婷[1] 张灵[1] 胥利蛟[1] 

机构地区：[1]西南石油大学化学化工学院,四川成都610500

出　　处：《石油学报（石油加工）》2011年第5期687-693,共7页Acta Petrolei Sinica(Petroleum Processing Section)

基　　金：国家自然科学基金(20906075);四川省教育厅青年基金(08ZB003);油气藏地质与开发工程国家重点实验室开放基金(PLN0907)资助

摘　　要：分别采用双滴法、尿素法和超声波法合成镁铝水滑石LDH-CP、LDH-UR和LDH-US,以XRD、N2吸附-脱附、TG-DSC和Hammett碱强度-碱量表征它们的物化性质,以催化原油酯化脱酸反应评价它们的催化性能,并推测反应机理。结果表明,兼具高结晶度和高碱量的水滑石具有最佳的催化酯化活性,既能使醇生成强亲核性的R1O-,又避免了导致副反应的游离R1O-的产生。LDH-UR结晶度最高,但碱量最低;LDH-US碱量最高,但结晶度最低;LDH-CP兼具高结晶度和高碱量,有最高的脱酸活性,可将绥中原油酸值从3.72mgKOH/g降到0.40mgKOH/g以下。Three carbonate hydrotalcites（LDH） with same molar ratio of Mg and Al were prepared by constant pH,urea and ultrasonic coprecipitation methods,respectively,and named as LDH-CP,LDH-UR,LDH-US.Their properties were characterized by XRD,N2 adsorption-desorption and thermal analysis.The basicity strength and basic sites amount of the three hydrotalcites were measured by Hammett indicator-benzene carboxylic acid titration,and furthermore,their catalytic activity in the esterification reaction of petroleum acid and glycol was investigated.Based on the characterization and activity assessment results,the esterification reaction mechanism catalyzed by hydrotalcite was discussed.It was found that the hydrotalcite with both more basic sites and higher crystallinity exhibited better catalytic esterification activity.Large amount of basic sites and regular crystal structure favored to producing strong nucleophilicity R1O-anions as well as preventing the formation of free R1O-anions which can cause side reaction.Among the three hydrotalcites,LDH-UR had the highest crystallinity but the smallest amount of basic sites,LDH-US had the poorest crystallinity but the largest amount of basic sites,LDH-CP had both more basic sites amount and higher crystallinity,which showed the best catalytic activity in the esterification reaction of petroleum acid and glycol.Through the esterification reaction catalyzed by LDH-CP the acid number of Suizhong crude oil could be decreased from 3.72 mgKOH/g to less than 0.40 mgKOH/g.

关 键 词：镁铝水滑石 制备方法 碱性 酯化 脱酸 

分 类 号：TQ028.8[化学工程]