Preparation method of ethoxyquin serving as antioxidant

Abstract

The invention discloses a preparation method of ethoxyquin serving as an antioxidant. The preparation method comprises the concrete steps of heating to react after mixing 2-nitro-5-ethoxyphenylboronic acid, DMF, sodium carbonate, tetrakis(triphenylphosphine)palladium and 4-bromo-2-methyl-2-hydroxyl-3-pentene; then, filtering the reactants, carrying out reduced pressure distillation and re-crystallizing to obtain a faint yellow solid; adding a hydrochloric acid solution and stannous chloride dihydrate, and reacting for 10-16 hours by stirring; next, extracting a reaction solution by using dichloromethane, sequentially washing an organic phase by using a sodium carbonate solution, water and a saturated sodium chloride solution; and removing a solvent after drying to obtain an oily matter, namely ethoxyquin serving as the antioxidant. According to the preparation method, a novel synthesis route is adopted, and a great deal of methylbenzene and acetone are not needed in synthesis reaction, so that human injuries can be reduced, and environment pollution can be reduced; and the reaction conditions are mild, the reaction time is short, and the purity of ethoxyquin in a final product obtained through reaction is larger than 97% which is far higher than the purity of the existing product sold on the market.

Description

technical field [0001] The invention relates to the field of chemical industry, in particular to a preparation method of antioxidant ethoxyquinoline. Background technique [0002] Ethoxyquinoline, also known as "Antioxidant", is a commonly used feed antioxidant. Commercial application has a history of nearly 60 years. Although there are many types of antioxidants on the market, such as traditional BHT, expensive BHA, and efficient TBHQ, etc., a comprehensive comparison of the effects and price factors of single species of feed antioxidants found that , Ethoxyquinoline has low cost and good antioxidant effect, and is still the preferred antioxidant species in the world feed industry. [0003] my country began to use ethoxyquinoline as a feed antioxidant in the mid-1980s, and promulgated the national standard for food additive ethoxyquinoline (GB8849-88) in 1988, which is suitable for premixes, fish meal and additives Fatty products can protect vitamins A, D, E and other vita...

AI Technical Summary

Problems solved by technology

However, the reaction time is long (generally more than 48 hours), the conversion rate is lower than 90%, and the product purity is low (the purity range of commercially available products is 80-90%), which cannot meet the needs of the high-end feed market; A certain amount of p-aminophenethyl ether will remain in the product, which not only affects the product quality, but also p-aminophenethyl ether is a toxic substance that can cause cancer and threatens human health. Therefore, in order to ensure the complete reaction of p-aminophenethyl ether, it is often necessary to Acetone and toluene, which far exceed the theoretical amount, are used as reaction raw materials and solvents, which increase production costs and cause waste of resources; in addition, in conventional synthetic routes, raw materials such as soda ash, caustic soda, and hydrochloric acid are needed to achieve rectification conditions, and the reaction costs are high. , The amount of exhaust gas emissions is large, polluting the environment

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