硅烷基Schiff碱共价修饰纳米二氧化硅负载过渡金属催化乙烯齐聚性能  

Catalytic Properties of Silylated-Salicylaldimine Transition Metal Complexes Functionalized Nano-silica Catalysts in Ethylene Oligomerization

作　　者：李锋[1] 路世玉 张宇[1] 郭丽君 翟雪 李翠勤[1] LI Feng;LU Shi-Yu;ZHANG Yu;GUO Li-Jun;ZHAI Xue;LI Cui-Qin(Provincial Key Laboratory of Petroleum and Natural Gas Chemical Engineering,College of Chemistry and Chemical Engineering,Northeast Petroleum University,Daqing 163318,China)

机构地区：[1]东北石油大学化学化工学院,石油与天然气化工省重点实验室,大庆163318

出　　处：《应用化学》2022年第6期949-959,共11页Chinese Journal of Applied Chemistry

基　　金：黑龙江省自然科学基金(No.E2018012);黑龙江省博士后启动基金(No.16190023)资助。

摘　　要：将3种水杨醛Schiff亚胺配合过渡金属(Si-Schiff-M,M=Ni,Co,Cr)通过共价键接枝到纳米二氧化硅,制备了3种硅烷基Schiff碱共价修饰纳米二氧化硅负载过渡金属催化剂(Si-Schiff-SiO_(2)-M),并对其催化乙烯齐聚性能进行了研究;采用元素分析、红外光谱、扫描电子显微镜和电感耦合等离子色谱表征了3种Si-Schiff-SiO_(2)-M的结构和形貌。以甲基铝氧烷(MAO)为助催化剂,研究了反应条件及催化活性中心种类对3种Si-Schiff-SiO_(2)-M催化乙烯齐聚产物性能的影响。结果表明,当Si-Schiff-SiO_(2)-M用量为7μmol,n(Al)/n(M)(M=Cr,Ni,Co)为500,反应温度为35℃,反应压力为0.5 MPa和反应时间为30 min时,Si-Schiff-SiO_(2)-Cr、Si-Schiff-SiO_(2)-Ni和Si-Schiff-SiO_(2)-Co催化乙烯齐聚活性分别为1.92×10^(5)g/(mol Cr·h)、2.17×10^(5)g/(mol Ni·h)和2.07×10^(5)g/(mol Co·h),且3种催化剂催化乙烯齐聚产物主要是C4和C6烯烃。Si-Schiff-SiO_(2)-M由于载体的限域效应,其催化乙烯齐聚活性低于相应的均相催化剂(Si-Schiff-M),但产物分布较均相催化剂窄。Si-Schiff-SiO_(2)-M具有良好的循环利用性,3次循环使用后,3种负载型催化剂催化乙烯齐聚活性分别为1.39×10^(5)g/(mol Cr·h)、1.68×10^(5)g/(mol Ni·h)和1.42×10^(5)g/(mol Co·h)。Three kinds of silylated-salicylaldimine transition metal complexes functionalized nano-silica catalysts were prepared with silylated-salicylaldimine transition metal complexes as precursors and with nano-silica as support.Three kinds of heterogeneous catalysts were characterized by elemental analysis,FT-IR,SEM and ICP.The effect of the reaction parameters and the kinds of catalytic active center on the catalytic properties of the three heterogeneous catalysts were investigated with methylaluminoxane(MAO)as the cocatalyst.The results show that when the precatalyst dosage is 7μmol,the molar ratio of Al/M(M=Cr,Ni,Co)is 500,the reaction temperature is 35℃,the reaction pressure is 0.5 MPa and the reaction time is 30 min,the catalytic activities for Si-Schiff-SiO_(2)-Cr,Si-Schiff-SiO_(2)-Ni and Si-Schiff-SiO_(2)-Co in ethylene oligonerization are 1.92×10^(5)g/(mol Cr·h),2.17×10^(5)g/(mol Ni·h)and 2.07×10^(5)g/(mol Co·h),respectively,and the main oligomers are C4 and C6 olefin.Si-Schiff-SiO_(2)-M has lower catalytic activity and narrower product distribution compared to the corresponding homogeneous catalyst due to the low loading of metal active center and the confinement effect of the support.Si-Schiff-SiO_(2)-M has the good repeatability and the better thermal stability,and the activity of the recovered catalyst is up to 1.39×10^(5)g/(mol Cr·h),1.68×10^(5)g/(mol Ni·h)and 1.42×10^(5)g/(mol Co·h),respectively after three oligomerization reactions.

关 键 词：乙烯齐聚 纳米二氧化硅 负载催化剂 共价修饰 硅烷基水杨醛亚胺 

分 类 号：O643.3[理学—物理化学]