A Comparative Study of Solvent-Free and Highly Efficient Pinene Hydrogenation over Pd on Carbon, Alumina, and Silica Supports

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• 作者：Ayyoub Selka ; Natalie A. Levesque ; Delphine Foucher ; Olivier Clarisse ; Farid Chemat ; Mohamed Touaibia
• 刊名：Organic Process Research & Development
• 出版年：2017
• 出版时间：January 20, 2017
• 年：2017
• 卷：21
• 期：1
• 页码：60-64
• 全文大小：305K
• ISSN：1520-586X

文摘

Solvent-free catalytic hydrogenation of pinene over Pd on carbon, alumina, and silica supports were compared. Despite the absence of solvent, Pd catalyst on all three supports yields to a quantitative conversion of pinene to pinanes and a higher selectivity for the cis isomer (72–89%). The temperature affected similarly the selectivity of the reaction for all three catalysts in favor of the cis-pinane isomer. However, recycling of the Pd on the three tested supports varied greatly. If Pd/C and Pd/alumina were successfully recycled 13 and 14 times, respectively, Pd/silica could be used only once to convert pinenes into pinanes. Remaining very effective during all 13 cycles, Pd/C was the best catalyst/support of the three tested ones for the solvent-free hydrogenation of pinene. The influence of H₂ pressure on pinene conversion rates were investigated for Pd/C catalyst. An extremely low leaching rate of palladium in pinenes and pinanes determined by ICP/MS confirmed the heterogeneous nature of this catalytic solvent-free reaction. The hydrogenation reaction presented in this paper is an alternate environmentally friendly pathway for pinane synthesis.