甲酸與鈀／活性碳對二苯甲酮催化還原反應之動力學研究

Kinetic Studies on the Catalytic Reduction of Benzophenone by Formic Acid with Palladium on Carbon

林俊旭(Chun-Hsu Lin):許經世(Ching-Shih Hsu) ； 陳成(Cheng Chen) ； 梁建錚(Jang-Jeng Lieng)

《化學》 45卷3期 (1987/09) Pp. 120-126

https://doi.org/10.6623/chem.1987028

摘要

甲酸在鈀／活性碳的催化下，可將二苯甲酮還原成二苯甲烷。本文將利用氣相層析儀分析二苯甲酮的濃度來進行此一反應的動力學研究。在過量的甲酸溶液中，此還原反應是屬僞一級反應。反應速率隨催化劑用量及溶劑的介電常數增加而加快。在95%乙醇水溶液中的活化能爲68.58kJ mol^(-1)，活化熵爲-0.47 kJ mol^(-1)K^(-1)，活化能與活化熵隨溶劑介電常數的增加而減少。此催化還原反應的反應機構在本文中亦有詳細的討論。

並列摘要

Benzophenone can be catalytically reduced to diphenyl methane by formic acid in the presence of Pd/C. Kinetic studies of this reduction have been performed by measuring the concentration of benzophenone with gas chromatography. The order of the reaction was determined to be pseudo first order reaction in large excess formic acid. The rate constant was dependent on the amount of catalyst and the dielectric constant of solvent. The activation energy and entropy were estimated to be 68.58 kjmol^(-1) and -0.47 kjmol^(-1)k^(-1), respectively, in 95% aqueous ethanol. The activation energy and entropy are decreased with increasing the dielectric constant of solvent. In this paper, the mechanism of this catalytic reduction have been discussed.