The Synthesis Of Vanillin

Vanillin is a typical food additives, which has been used widely in agriculture, food industry, chemical industry and medicine with the continuous development of science and technology. However, in domestic, the vanillin development is relatively slow, not only the production but also the product purity have not reached the international level. Accordingly, the development of vanillin has become the top priority.Nowadays, most industrial process for the synthesis of the vanillin is based on a two-step procedure:(i) condensation reaction of glyoxalic acid with guaiacol and (ii) oxidative decarboxylation of the intermediary 3-methoxy-4-hydroxymandelic acid (vanillymandelic acid). On the basis of forefathers, particular attention was paid to the second step, using mesoporous CuO as the catalyst for selective oxidation of 3-methoxy-4-hydroxymandelic acid to vanillin in the second chapter. The effects of reaction conditions has been investigated, and he best conditions were:reaction temperature 85℃, oxygen pressure 0.45MPa, PH 12.5, reaction time 6h, catalyst amount 46mg, and the yield 88.3% of the goal product could be achieved.Vanillin is prepared by dehydrogenation of 4-hydroxy-3-methoxybenzyl alcohol for the first time in the third chapter, we investigates the versatility and the recyclability of the Pd0 catalyst in water, indicating that the system is highly efficient and green. The yield of vanillin is>99%, it proved that this method is suitable for industrial production.