Improved process for 2,3,5-trimethylhydroquinone manufacture: highly efficient catalytic hydrogenation of 2,3,5-trimethylbenzoquinone

摘要

An efficient and green process of catalytic hydrogenation of 2,3,5-trimethylbenzoquinone (TMBQ) to 2,3,5-trimethylhydroquinone (TMHQ) on Pd/C catalyst using the LBA (a commercial mixed solvent) as solvent is described. The important reaction parameters (e.g. temperature, catalyst loading, initial concentration of TMBQ, hydrogen pressure, and agitation speed) have been investigated to acquire the optimal process conditions. The hydrogenation molar yield of TMHQ by HPLC analysis is 99.4 %. The solvent could be recovered by steam distillation, while the isolated TMHQ overall molar yield reaches up to 96.7 %. The deactivation of Pd/C during the reuse of catalysts was ascribed to the depositions of TMHQ and TMBQ based on various characterizations and regeneration study of catalyst. The possible catalytic hydrogenation mechanism is also discussed.