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

Khodadadi Moghaddam, M ; Sharif University of Technology | 2008

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  1. Type of Document: Article
  2. DOI: 10.1016/j.apcata.2008.02.002
  3. Publisher: 2008
  4. Abstract:
  5. 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 (ETN), hydrogen-bond acceptor basicity (β) and hydrogen-bond donor acidity (α) 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 α, π* and β and ETN 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. © 2008 Elsevier B.V. All rights reserved
  6. Keywords:
  7. Alcohols ; Catalyst activity ; Hydrogenation ; Ionic liquids ; Parameter estimation ; Solvents ; Heterogeneous catalytic hydrogenation ; Reactants ; Solvatochromic parameters ; Solvent effects ; Cyclohexane
  8. Source: Applied Catalysis A: General ; Volume 341, Issue 1-2 , 2008 , Pages 58-64 ; 0926860X (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/abs/pii/S0926860X08000707