METHOD OF PREPARING VANILLIN

• Main Authors: WANG, Lizhi, LIU, Zhenjiang, YAO, Yueliang, MAO, Haifang, WU, Jianxin, WANG, Chaoyang, ZHAO, Feifei
• Format: Patent
• Language: English; French; German
• Published: 12.05.2021
• Subjects: ACYCLIC OR CARBOCYCLIC COMPOUNDS; CHEMISTRY; METALLURGY; ORGANIC CHEMISTRY

A method of preparing vanillin comprises weighing eugenol, a strong alkali, a catalyst, and a first organic solvent, respectively, the molar ratio of the strong alkali to eugenol being 1 : 2-15, the amount of the catalyst being 0.1% to 2.0% of the weight of eugenol, and the volume of the first organic solvent being 3 to 10 folds of the volume of eugenol; adding the above substances to a reactor, respectively, the reaction pressure being 0.01-0.30 MPa, heating to 60-120°C under stirring, then beginning to introduce oxygen gas to control partial pressure of oxygen gas within 0.01-1 MPa, and performing oxidation reaction for 4-30 h; cooling to room temperature, adding water with the volume ratio of water to the first solvent being 0.5 to 2, adjusting to neutrality with an acid solution, recovering the first organic solvent, extracting the water phase with a second organic solvent, carrying out reduced pressure distillation, crystallizing with a mixed solvent of ethanol and water, and drying to give vanillin. In the present invention, vanillin is synthesized directly without protection of phenolic hydroxyl group of eugenol, isomerization of eugenol or other processes. The invention is simple in process and convenient for post treatment.