UiO-66-NH_(2)接枝吡啶亚胺钴系催化剂的合成及催化乙烯齐聚性能

Synthesis of UiO-66-NH_(2) Grafted Pyridineimine Cobalt Catalyst and Its Catalytic Performance in Ethylene Oligomerization

以金属有机骨架(MOFs)UiO-66-NH_(2)和吡啶-2-甲醛为原料,采用后合成修饰法制备一种UiO-66-NH_(2)接枝吡啶亚胺配体,然后以UiO-66-NH_(2)接枝吡啶亚胺配体和CoCl_(2)·6H_(2)O为原料,经配合反应,合成出一种UiO-66-NH_(2)接枝吡啶亚胺钴系催化剂。采用傅里叶红外变换光谱(FT-IR)、X射线衍射(XRD)、扫描电子显微镜(SEM)、电感耦合等离子体质谱(ICP-MS)和氮气吸附-脱附等方法对合成产物的结构进行了表征,并考察了该催化剂在乙烯齐聚反应中的催化性能。研究结果表明,反应温度、n(Al)/n(Co)和乙烯压力对催化乙烯齐聚活性和产物选择性均有较大的影响,当以环己烷为溶剂,甲基铝氧烷(MAO)为助催化剂,在反应温度为25℃、n(Al)/n(Co)为1000、乙烯压力为1.0 MPa时,UiO-66-NH_(2)接枝吡啶亚胺钴系催化剂催化乙烯齐聚的活性可达1.23×10^(5) g/(mol_(Co)·h),对丁烯的选择性为88.96%。

UiO-66-NH_(2)grafted pyridineimine ligand was prepared by post synthetic modification with metal organic frameworks(MOFs)UiO-66-NH_(2)and 2-pyridinecarboxaldehyde as raw materials,and then a novel UiO-66-NH_(2)grafted pyridineimine cobalt catalyst was synthesized by complexation reaction with UiO-66-NH_(2)grafted pyridineimine ligand and CoCl_(2)·6 H_(2)O as raw materials.The structure of the products was characterized by Fourier transform infrared spectroscopy,X-ray diffraction,scanning electron microscope,inductively coupled plasma mass spectrometry and nitrogen adsorption-desorption,and the catalytic performance of the UiO-66-NH_(2)grafted pyridineimine cobalt catalyst in ethylene oligomerization was investigated.The results show that the reaction temperature,Al/Co molar ratio and ethylene pressure have a significant effect on the catalytic activity and products selectivity.The catalytic activity of 1.23×10^(5)g/(mol_(Co)·h)and 88.96% selectivity of butene are obtained under the condition of the reaction temperature 25℃,Al/Co molar ratio of 1000 and ethylene pressure of 1.0 MPa.