Effect and Mechanism of Aluminum(III) for Guaiacol-Glyoxylic Acid Condensation Reaction in Vanillin Production.

ABSTRACT: 3-methoxy-4-hydroxymandelic acid (VMA) was the critical intermediate for the synthesis of vanillin by the glyoxylic acid method. Meanwhile, a valuable byproduct (2-hydroxy-3-methoxy-mandelic acid, o-VMA) was obtained during the reaction. Al³⁺ was found to be a helpful catalyst in increasing the selectivity for VMA and o-VMA. In the presence of Al³⁺, the selectivity for VMA and o-VMA increased from 83 to 88% and from 3 to 8%, respectively, while that of the helpless byproduct 2-hydroxy-3-methoxy-1,5-mandelic acid (di-VMA) decreased from 14% to less than 4%. The kinetics based on the kinetic equation of the condensation reaction was studied by the initial concentration method. The results indicated that the involvement of Al³⁺ could reduc

SUBMITTER: Mao H 

PROVIDER: S-EPMC7528326 | biostudies-literature | 2020 Sep

REPOSITORIES: biostudies-literature