Studies on the Utilization of Alkali Lignin (Part 3)

Abstract

Condition necessary for oxidation of lignin by air have been studied. Variables considered : time of reaction, temperature, weight of air, isolation method of pure vanillin. Vanillin was identified as an important product of the reaction when carried out at high temperature.Studies were made on the use of crude alkali lignin from black liquor of soda pulp waste liquor as raw material for the production of vanillin. The results indicated that air oxidation was as amenable to crude alkali lignin as alkali nitrobenzene oxidation. Optimum conditions yield of vanillin was about 6.90% of lignin (in vanillin 2, 4-dinitrophenyl-hydrazone, 7.53%).Isolation method of pure vanillin depending upon condition by sublimation have been discovered, and yield of pure vanillin was 4.80% of lignin (purity 90.2%).