预热处理温度对Ag-NH_(3)/SBA-15催化剂表面Ag物种形成及其催化性能的影响  

Effect of Preheating Temperature on the Formation of Ag Species on the Surface of Ag-NH_(3)/SBA-15 Catalyst and Its Catalytic Performance

作　　者：李天佑 朱凌彬 林凌[2] 黄隆 陈冲冲 叶闰平 姚元根[2] LI Tianyou;ZHU Lingbin;LIN Ling;HUANG Long;CHEN Chongchong;YE Runping;YAO Yuangen(College of Chemical Engineering,Fuzhou University,Fuzhou 350116,China;Key Laboratory of Coal to Ethylene Glycol and Its Related Technology,Fujian Institute of Research on the Structure of Matter,Chinese Academy of Sciences,Fuzhou 350002,China;College of Chemistry and Chemical Engineering,Nanchang University,Nanchang 330031,China)

机构地区：[1]福州大学石油化工学院,福建福州350116 [2]中国科学院福建物质结构研究所煤制乙二醇及相关技术重点实验室,福建福州350002 [3]南昌大学化学化工学院,江西南昌330031

出　　处：《石油学报（石油加工）》2023年第4期835-844,共10页Acta Petrolei Sinica(Petroleum Processing Section)

基　　金：国家重点研发计划项目(2018YFA0704500);国家自然科学基金项目(22102186);福建省自然科学基金项目(2019J05156,2019H0053);中国科学院战略性先导科技专项(XDA21020800)资助。

摘　　要：采用浸渍法将有序介孔分子筛SBA-15浸渍于银氨溶液中制备催化剂前驱体,然后在不同预热处理温度下制备了Ag-NH_(3)/SBA-15系列催化剂样品,并考察了其催化草酸二甲酯(DMO)加氢制备乙醇酸甲酯(MG)的反应性能。结果表明:控制适当的预热处理温度(如623 K)有利于生成更多能与硅羟基形成Ag—O—Si键的Ag 2O颗粒,从而抑制Ag物种的团聚,提高表面Ag物种分散度,还有利于形成更多带部分正电荷的Ag^(δ+)活性位,使H_(2)分子更容易被活化,进而提高Ag-NH_(3)/SBA-15催化剂的活性;在温度为483 K、压力为2.0 MPa、H_(2)/DMO摩尔比为100、液时质量空速(MHSV)为1.4 h^(-1)的反应条件下,Ag-NH_(3)/SBA-15-623K催化剂作用下DMO的加氢转化率为97.9%、MG的选择性和收率分别为94.9%和92.9%。First,catalyst precursors were prepared by the impregnation method,i.e.,impregnating the ordered mesoporous molecular sieve SBA-15 in silver ammonia solution;next,a series of Ag-NH_(3)/SBA-15 catalyst samples were obtained under different preheating temperatures,and their catalytic performance for hydrogenation of dimethyl oxalate(DMO)to prepare methyl glycolate(MG)were also investigated.The results show that an appropriate preheating temperature(e.g.623 K)is beneficial to the generation of more Ag 2O particles which can form the Ag—O—Si bonds with silicon hydroxyls,thus inhibiting the agglomeration of Ag species and improving the dispersion of Ag species on surface.Meanwhile,it is also beneficial to the formation of more active sites of Ag^(δ+)with partial positive charge,so that H_(2)molecules can be easily activated to further improve the activity of Ag-NH_(3)/SBA-15 catalyst.At the temperature of 483 K,the pressure of 2.0 MPa,the H_(2)/DMO molar ratio of 100 and the mass liquid hourly space velocity(MHSV)of 1.4 h^(-1),under the catalysis of Ag-NH_(3)/SBA-15-623K,the DMO hydrogenation conversion is 97.9%,MG selectivity and yield are 94.9%and 92.9%respectively.

关 键 词：Ag基催化剂 SBA-15 预热处理温度 Ag物种 草酸二甲酯 乙醇酸甲酯 

分 类 号：TQ426.81[化学工程]