高选择性和稳定性的CsPW/Nb_2O_5催化剂用于甘油脱水制备丙烯醛(英文)  

Highly selective and stable CsPW/Nb_2O_5 catalysts for dehydration of glycerol to acrolein

作　　者：刘蓉[1] 王铁峰[1] 刘畅[1] 金涌[1] 

机构地区：[1]清华大学化学工程系 绿色反应工程与工艺北京市重点实验室,北京100084

出　　处：《催化学报》2013年第12期2174-2182,共9页

基　　金：supported by the Program for New Century Excellent Talents in University(NCET‐12‐0297)~~

摘　　要：以磷钨酸铯盐Cs2.5H0.5PW12O40(CsPW)为活性组分,负载到Nb2O5载体上,并用于甘油脱水制备丙烯醛的反应中.通过调节焙烧温度(400–700°C)以及活性组分负载量(5儃60 wt%),对催化剂酸性进行调节.CsPW负载量为20 wt%,500°C焙烧的CsPW/Nb2O5催化剂性能最佳,甘油转化率为96%,丙烯醛选择性为80%,反应10 h内没有失活现象,并且该催化剂具有良好的热稳定性,可通过烧炭进行再生.Acrolein production by gas-phase dehydration of glycerol at 300 °C, catalyzed by a Cs+-substituted Keggin-type phosphotungstate, Cs2.5H0.5PW12O40 (CsPW), supported on Nb2O5 was investigated. The catalysts were characterized using N2 adsorption-desorption, X-ray diffraction, Fourier-transform infrared and Raman spectroscopies, and NH3 temperature-programmed desorption. It was demon-strated that Lewis acid sites were responsible for byproduct formation, and that Br?nsted acid sites of medium strength were the active sites for acrolein production by glycerol dehydration. The acid-ity of the supported CsPW was affected by the calcination temperature and CsPW loading. The CsPW was well dispersed on Nb2O5 at loadings￡20 wt%, and the strong acid sites of bulk CsPW were converted to selective medium acid sites. The CsPW catalyst with 20%of CsPW loading cal-cined at 500 °C gave 96%of glycerol conversion and 80%of acrolein selectivity, and there was no significant deactivation in 10 h. The catalyst with a 20%decrease in activity was regenerated by simple coke burning with air at 500 °C.

关 键 词：甘油脱水 丙烯醛 五氧化二铌 磷钨酸铯盐 

分 类 号：TQ224.132[化学工程—有机化工]