Synthetic method of ethyl salicylate

Abstract

The invention belongs to the field of chemical engineering, and particularly discloses a synthetic method of ethyl salicylate with high purity and conforming to drug use. The method comprises the steps of using sulfuric acid for catalytic synthesis of the ethyl salicylate, washing a product and purifying the product; a mixture of ethanol and water is collected while ethanol with high concentration is added to a reaction system in the synthesis process, forward esterification reaction can be effectively promoted, and the improvement of the reaction yield is facilitated; the obtained ethyl salicylate product is high in purity, no unknown impurities are introduced, the requirements of the drug use are met, the quality is guaranteed from raw materials, and the unknown risk of the product during clinical use is reduced.

Description

technical field [0001] The invention belongs to the field of chemical industry, in particular to a method for synthesizing ethyl salicylate with high purity and suitable for medicinal use. Background technique [0002] Ethyl salicylate is a colorless liquid with a special aroma similar to holly, and it gradually turns yellow-brown when exposed to light or left for a long time. It can be used medicinally as a fixative for daily flavors or food flavors; it can be used as an intermediate, such as for salicylamide, ethyl acetylsalicylate, ethyl nitrosalicylate; it can also be used Used as a solvent, such as a solvent for nitrocellulose, etc., is an important class of ester compounds. [0003] The catalysts that can catalyze the reaction of salicylic acid and ethanol to generate ethyl salicylate mainly include solid superacid catalysts, p-toluenesulfonic acid catalysts, sodium bisulfate catalysts and concentrated sulfuric acid catalysts. A solid superacid is an acid stronger th...

AI Technical Summary

Problems solved by technology

A solid superacid is an acid stronger than 100% sulfuric acid, such as using The solid superacid catalyst catalyzes the reaction of salicylic acid and ethanol, and the yield can reach 89% (referring to "Fine Petrochemical Industry", 1997 (7): 3); The solid superacid catalyst catalyzes the reaction of salicylic acid and ethanol, and the yield of ethyl salicylate can reach 84.6% (referring to "Inner Mongolia Petrochemical Industry", 2001, 27:37), but after utilizing this type of solid superacid to catalyze the reaction The processing is more complicated, and other impurities are easily introduced. The obtained ethyl salicylate has unknown risks when it is used for clinical use, and the preparation of solid superacid is time-consuming, usually one week, and the reusability of the solid superacid has yet to be determined. Further exploration, it is difficult to be used in industrial production

[0004] P-toluenesulfonic acid can also achieve better results as an acid-catalyzed reaction between salicylic acid and ethanol. For example, patent application 201410632341 discloses a method for the synthesis of ethyl salicylate catalyzed by p-toluenesulfonic acid. First, the raw materials and catalyst are heated and stirred After a period of time, reflux in a microwave reaction device for a period of time, and finally transfer to a distillation device for reaction, the yield of ester can reach 89%, but there are many devices required when using this method for preparation, and the post-treatment process is complicated. Toluene Sulfonic acid is difficult to remove, and the obtained ethyl salicylate has potential risks for medicinal use

[0005] Sodium bisulfate catalyst has stable performance during catalysis, is insoluble in organic matter, easily soluble in water, has good catalytic activity, and the yield can reach 70-80% (see "Industrial Catalysis", 2006, 14 (5), 42-44), but Its yield is not high even under pressurized conditions, which cannot meet the needs of industrial reactions

[0006] Sulfuric acid catalyzed synthesis of ethyl salicylate is a common method. Under sulfuric acid catalyzed conditions, salicylic acid and ethanol undergo esterification reaction through heating to generate ethyl salicylate, which is obtained during the synthesis of ethyl salicylate by this conventional method. Low product yield, easy to cause waste of raw materials

Images