Kinetic study of heterogeneous catalytic hydrogenation of cyclohexene to cyclohexane in ionic liquid–alcohols mixtures

详细信息	查看全文 | 推荐本文 |

• 作者：Mohammad Khodadadi-Moghaddam ; Aziz Habibi-Yangjeh ; Mohamad Reza Gholami
• 关键词：Ionic liquid ; Heterogeneous catalytic hydrogenation ; Solvatochromic parameters ; Solvent effects
• 刊名：Applied Catalysis A ; General
• 出版年：2008
• 期刊代码：4_0926860x
• 类别：ch
• 出版时间：15 June 2008
• 卷：341
• 期：1-2
• 页码：58-64
• 文件大小：365 K

摘要

Heterogeneous catalytic hydrogenation of cyclohexene, catalyzed by Pt/Al₂O₃, was carried out in solutions of 2-hydroxyethylammonium formate (a room temperature ionic liquid, RTIL) mixed with methanol, ethanol and propan-2-ol at 25 °C. The rate constants of the reaction in ionic liquid alcohol mixtures were higher than alcohol alone. First-order rate constant of the reaction in the RTIL relative to propan-2-ol is approximately 28. Furthermore, the rate constant of the reaction increases with the mole fraction of the ionic liquid. Single-parameter correlations of log k vs. normalized polarity parameter (), hydrogen-bond acceptor basicity (β) and hydrogen-bond donor acidity () do not give acceptable results in the solutions. In addition, log k does not show an acceptable dual-parameter correlation with π* (dipolarity/polarizibility, one of the Kamlet–Taft parameters for solvent that shows the dipolarity of the solvent) and , π* and β and and β. However single-parameter correlation of log k vs. π^* gives reasonable results. The increase of the reaction rate with π^* is attributed to the non-polar nature of the reactants.