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Insights into the Major Reaction Pathways of Vapor‐Phase Hydrodeoxygenation of m ‐Cresol on a Pt/HBeta Catalyst
Author(s) -
Sun Qianqian,
Chen Guanyi,
Wang Hua,
Liu Xiao,
Han Jinyu,
Ge Qingfeng,
Zhu Xinli
Publication year - 2016
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201501232
Subject(s) - methylcyclohexane , hydrodeoxygenation , chemistry , catalysis , deoxygenation , toluene , cresol , activation energy , photochemistry , organic chemistry , selectivity , phenol
Abstract Conversion of m ‐cresol was studied on a Pt/HBeta catalyst at 225–350 °C and ambient hydrogen pressure. At 250 °C, the reaction proceeds through two major reaction pathways: (1) direct deoxygenation to toluene (DDO path); (2) hydrogenation of m ‐cresol to methylcyclohexanone and methylcyclohexanol on Pt, followed by fast dehydration on Brønsted acid sites (BAS) to methylcyclohexene, which is either hydrogenated to methylcyclohexane on Pt or ring‐contracted to dimethylcyclopentanes and ethylcyclopentane on BAS (HYD path). The initial hydrogenation is the rate‐determining step of the HYD path as its rate is significantly lower than those of subsequent steps. The apparent activation energy of the DDO path is 49.7 kJ mol −1 but the activation energy is negative for the HYD path. Therefore, higher temperatures lead to the DDO path becoming the dominant path to toluene, whereas the HYD path, followed by fast equilibration to toluene, is less dominant, owing to the inhibition of the initial hydrogenation of m ‐cresol.