物理化学学报 >> 2000, Vol. 16 >> Issue (03): 226-231.doi: 10.3866/PKU.WHXB20000307

研究论文 上一篇    下一篇

CO2和CH3OH直接合成碳酸二甲酯Cu-Ni/V2O5-SiO2催化剂

钟顺和, 黎汉生, 王建伟, 肖秀芬   

  1. 天津大学化工学院,天津 300072
  • 收稿日期:1999-06-24 修回日期:1999-09-14 发布日期:2000-03-15
  • 通讯作者: 钟顺和

Cu-Ni/V2O5-SiO2 Catalyst for the Direct Synthesis of Dimethyl Carbonate from Carbon Dioxide and Methanol

Zhong Shun-He, Li Han-Sehng, Wang Jian-Wei, Xiao Xiu-Fen   

  1. College of Chemical Engineering and Technology,Tianjin University,Tianjin 300072
  • Received:1999-06-24 Revised:1999-09-14 Published:2000-03-15
  • Contact: Zhong Shun-He

摘要:

采用表面反应改性法制备了V2O5-SiO2(VSiO)表面复合物 ,用等体积浸渍法制备了VSiO担载的Cu-Ni双金属催化剂 ,用IR、TPD、TPSR和微反技术研究了CO2 和CH3OH在催化剂表面上的化学吸附与反应性能. 结果表明,在Cu-Ni/VSiO催化剂上存在着金属位Cu-Ni合金、Lewis酸位Vn +和Lewis碱位V=O三类活性中心 ;CO2 在金属位和Lewis酸位协同作用下可生成CO2卧式吸附态M -(CO) -O→Vn + ,此吸附态在138℃左右可解离成M -CO和V=O ;CH3OH在Lewis酸位和Lewis碱位协同作用下可形成解离吸附态V -OCH3和V -OH ;CO2 和CH3OH在Cu-Ni/VSiO催化剂表面上的反应产物主要为碳酸二甲酯(DMC)、CH2O、CO和H2O ,其生成DMC的选择性在85%以上.

关键词: 二氧化碳, 甲醇, 碳酸二甲酯, V2O5-SiO2复合氧化物, 双金属催化剂

Abstract:

The surface complex support of V2O5-SiO2(VSiO) was prepared by the method of surface reaction modification. VSiO supported Cu-Ni bimetallic catalysts were made using isovolumic impregnation. Adsorption and reaction of CO2 and CH3OH on catalyst were characterized by IR, TPD, TPSR and micro-reactor techniques. The results show that three active sites exist on Cu-Ni/VSiO catalyst: metal site(Cu-Ni alloy, denoted M), Lewis acid site(Vn+)and Lewis basic site(V=O); horizontally adsorped CO2, formed by shearingly adsorbed CO2 on M in cooperation with the adjacent Vn+, can dissociate into M-CO and V=O at about 138 ℃and methanol dissociated into V-OCH3 and V-OH cooperated with Vn+ and adjacent V=O; the mainly reaction products of the reaction of CO2 and CH3OH on Cu-Ni/VSiO catalyst are DMC (with selectivity over 85%), CH2O, CO and H2O.

Key words: Carbon dioxide, Methanol, Dimethyl carbonate, V2O5-SiO2 complex support, Binetallic catalyst, Surface reaction