Preparation method of vanillin

The invention belongs to the technical field of organic chemical industry, and particularly relates to a preparation method of vanillin. The preparation method includes: using 3-methoxy-4-hydroxybenzyl alcohol as a raw material and pure water as a solvent; under action of a Pd modified SBA-15 catalyst, enabling dehydrogenation reaction to obtain vanillin. The preparation method has the advantages that cost is low, and the water which is environment-friendly can be utilized as the solvent, so that using of conventional organic solvents like methylbenzene and benzene is avoided; the solvent is easy to separate and recycle. 本发明属于有机化工技术领域，具体为种香兰素的制备方法。本发明以3-甲氧基-4-羟基苯甲醇为原料，以纯水为溶剂，在Pd改性SBA-15催化剂作用下经脱氢反应制备得到香兰素；本发明的有益效果在于，本发明成本低，可利用绿色环保的水为溶剂，避免了传统有机溶剂甲苯、苯的使用，催化剂容易分离和回收重复利用。