Caffeic acid is not only a metabolite of lignin synthesis pathway, but also an intermediate product of phenylpropane metabolism pathway in tobacco. Its appearance is yellow crystal, and it usually exists in the form of glucoside and ester. It is an organic acid and naturally exists in honeysuckle, vegetable thistle, wormwood and other plants.
According to relevant reports, using catechins as raw materials, caffeic acid can be obtained through substitution, oxidation, addition and other reactions. Caffeic acid can also be prepared by 3-methoxy-4-hydroxybenzaldehyde, 3, 4-dimethoxy-benzaldehyde, 3, 4-dimethoxy-benzaldehyde, 3, 4-methylenedioxy-benzaldehyde and substituted cinnamate through corresponding condensation, demethylation, hydrolysis and other chemical reactions. However, not all of these preparation methods are suitable for industrial production. For the production of caffeic acid, we advocate a green, scientific and reasonable development path.