Cu_2(μ-OMe)_2/SiO_2的结构与催化乙烯氢甲酰化反应性能的研究

Study on the Structure of Cu_2(μ-OMe)_2/SiO_2 Catalyst and Its Ethylene Hydroformylation Behaviors

采用表面改性和离子交换相结合的方法制得了负载型双核桥联配合物催化剂Cu2（μ-OMe）2／SiO2。用络合滴定化学分析、IR、BET、XRD、TEM、TG／DTA和微反技术考察了催化剂的物理化学结构、热稳定性和乙烯氢甲酰化反应性能。结果表明：催化剂表面的双核桥联结构中，金属离子Cu^2＋与载体SiO2表面O^2-以双齿配位键合，甲氧基以桥基形式连接双Cu^2＋形成双核物种Cu2（μ-OMe）2，这种桥联结构于176℃开始发生分解；在60～180℃温度范围内，C2H4、CO与H2在催化剂Cu2（μ-OMe）2／SiO2上发生反应，产物主要是丙醛和乙烷；反应温度、空速、压力及物料配比对乙烯转化率和丙醛选择性都有不同程度的影响。适宜条件（100℃、1000h^-1、0．6MPa、n（C2H4）／n（CO）／n（H2）=1／1／1）下，乙烯的转化率可达9％，丙醛选择性达86％。

A silica supported dinuclear complex, Cu2（μ-OMe）2/SiO2, was prepared by the method of surface modification combined with ion-exchange. The physico-chemical structures and thermal stability were characterized by methods of titration analysis, IR, BET, XRD, TEM and TG/DTA. Then, the reaction behaviors of ethylene hydroformylation over this catalyst were observed via microreactor technique. The results showed that the dinuclear bridged structure existed on the catalyst surface, copper （Ⅱ） bonded with the surface O^2- on SiO2 in bidentate fashion, bis-μ-OMe bridged structure Cu2 （μ-OMe）2 was formed between two copper （Ⅱ） ions and it began to decompose at 176℃. Hydroformylation of ethylene took place at 60-180℃ over this catalyst and produced propanal with ethane mainly. The temperature, space velocity, pressure and reactant composition had some influence upon the conversion of ethylene and the selectivity of propanal. Under the condition of 100℃, 1000h^-1 , 0.6MPa, n （C2H4）/n（CO）/n（H2） = 1/1/1 ,the conversion of ethylene was about 9% with the propanal selectivity of 86%.