Fine chemicals from lignosulfonates. 1. Synthesis of vanillin by oxidation of lignosulfonates

The oxidation of lignosulfonates (LS) to vanillin by persulphate, oxygen, and a variety of catalytic systems has been investigated. Cobalt and copper catalysts appeared to be the most effective in the oxidation by oxygen. An investigation where multivariate mathematical and statistical design and modelling have been used for the process optimisation has led to the development of a multivariate mathematical model which describes the oxidation process with high predictive capacity. By using this model, an increase of the vanillin yield from 4.1% of the current procedure to 7.2% is obtained, this corresponding to 75% relative improvement of the yield.