Ionic Liquid-mediated Catalytic Oxidation of Isoeugenol to Vanillin via Oxovanadium 1,3,5-Benzenetricarboxylate

Abstract

A series of oxovanadium 1,3,5-benzenetricarboxylate complex catalysts was prepared and characterized by FT-IR,diffuse reflectance UV-Vis( DR UV-Vis) and TG,respectively. The effects of catalyst,promoter such as ionic liquid,ionic liquid amount and reaction time on the oxidation of isoeugenol to vanillin were investigated systematically. VO( BTC)-1 with a molar ratio of VO2 +and BTC( 1,3,5-benzenetricarboxylate) as 1 ∶ 1 exhibits better catalytic performance. Complete conversion of isoeugenol and87. 2% yield of vanillin are achieved using VO( BTC)-1 as catalyst,1-dodecyl-3-methylimidazolium chloride([C12mim]Cl) as additive with the molar ratio of isoeugenol,H2O2 and [C12mim]Cl as 1∶2∶0. 01 after 24 h reaction at 20 ℃ in acetone. The formation of a highly effective oxidation system from [C12mim]Cl/VO(BTC)-1 and H2O2 is beneficial in the mild conversion of isoeugenol, as indicated by spectral characterization and the reaction results.