PdCl_2-CuCl_2/Li-Al-O对CO低压气相合成碳酸二乙酯反应的催化性能  

Catalytic Performance of PdCl_2-CuCl_2/Li-Al-O for Synthesis of Diethyl Carbonate from CO and Ethyl Nitrite at Low Pressure

作　　者：高晓晨[1] 马新宾[1] 王胜平[1] 李振花[1] 

机构地区：[1]天津大学化工学院绿色合成与转化教育部重点实验室,天津300072

出　　处：《催化学报》2007年第8期720-724,共5页

基　　金：'十一五'国家科技支撑计划(2006BAE02B00);教育部新世纪优秀人才支持计划(NCET-04-0242);天津市科技攻关项目(043185511-2)

摘　　要：采用Li NO3对γ-Al2O3进行改性,制备了以多孔锂铝尖晶石为载体,以Pd为活性组分的PdCl2-CuCl2/Li-Al-O负载型催化剂,并考察了催化剂对CO低压气相合成碳酸二乙酯(DEC)反应的催化性能,探讨了载体Li/Al比、改性浸渍方法、不同改性金属、Pd负载量和反应压力等因素对催化剂催化性能的影响.结果表明,当n(Li)/n(Al)=0.2,压力为0.3 MPa和温度为110℃时,DEC的时空收率可达到418 g/(L.h).用Li NO3对γ-Al2O3改性后的催化剂载体表层具有Li Al5O8尖晶石结构,不同Li/Al比的催化剂载体的晶胞参数、晶胞体积略有不同.采用双金属改性的催化剂载体表面由于结晶度较低不能形成'完全尖晶石结构',其催化活性较低.随着催化剂表面活性组分PdCl2含量的增加,可有效提高产物DEC的时空收率;锂铝尖晶石载体表面的酸性较低,有利于提高目标产物DEC的选择性.The catalytic performance of the PdCl2-CuCl2/Li-Al-O catalyst, with palladium as the active compo- nent and porous lithium alumina spinel （Li-Al-O） as the support, for vapor-phase synthesis of diethyl carbonate （DEC） from CO and ethyl nitrite was studied in a continuous fixed-bed reactor at low pressure. The Li-Al-O spinel support was synthesized by impregnation of γ-Al2O3 （2-3 mm） with aqueous LiNO3 solution. Under the mild reaction conditions of 5 % CO-20 % EtONO-75 % N2, GHSV = 2 500 h^- 1, 0.3 MPa, and 110 ℃ , the CO conversion was 40 % and the space time yield of DEC was 418 g/（L· h）. The perfectly close-packed spinel structure could be obtained because of the lithium ions that entered the vacancy of γ-Al2O3. The Li-Al-O catalyst support had no strong acid sites, and the catalyst had stable palladium chloride, both of which were favorable for the DEC synthesis reaction.

关 键 词：碳酸二乙酯 一氧化碳 亚硝酸乙酯 氯化钯 氯化铜 氧化铝 锂铝尖晶石 负载型催化剂 

分 类 号：O643.32[理学—物理化学]