Method for producing ethoxyquin

Abstract

The invention discloses a method for producing ethoxyquin, and relates to the field of chemical synthesis. The method includes the following steps: (1) adding p-phenetidine, a composite catalyst, and methylbenzene into a heatable reactor, adding acetone into the reactor under a heating condition to complete a condensation reaction, so as to obtain reacting liquid; (2) cooling the reacting liquid obtained in the step (1) to room temperature, adding an alkali liquor to neutralize the reacting liquid until the pH value is neutral, separating out the lower-layer catalyst and the remaining alkali liquor, and then adding water for water extraction to obtain the product mixed solution; (3) carrying out reduced pressure distillation on the product mixed solution obtained in the step (2) to obtain the ethoxyquin product. According to the invention, a p-toluenesulfonic acid / iodine composite catalyst is adopted for the preparation of ethoxyquin, and the catalyst matching ratio is adjusted, so that the product yield is improved while the production period is shortened, and the process cost is reduced.

Description

technical field [0001] The invention relates to the field of chemical synthesis, in particular to a production method of ethoxyquinoline which uses p-aminophenetole and acetone as raw materials and p-toluenesulfonic acid / iodine as a compound catalyst. technical background [0002] Ethoxyquinoline (6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline, English name Ethoxyquin, CAS No. 91-53-2) as a high-efficiency, low-toxicity, Inexpensive antioxidants are currently widely used in feed and food industries, which can prevent the main nutrients such as vitamins A, D, E, carotene and fatty acids from oxidizing and deteriorating, and have certain anti-mildew and fresh-keeping effects. In addition, ethoxyquinoline can also be used as an anti-aging agent for rubber, especially styrene-butadiene rubber, which has good oxidation resistance and ozone resistance, as well as good weather resistance and flex crack resistance. [0003] The currently reported ethoxyquinoline synthesis process ma...

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Problems solved by technology

[0004] Chinese patent CN1807416 uses p-aminophenethyl ether and acetone as raw materials and p-toluenesulfonic acid as a catalyst, and reduces the content of p-aminophenethyl ether in the product ethoxyquinoline to 1wt% by replacing the solvent in the water separator at the later stage of the reaction Below, but the process is cumbersome to operate, the amount of solvent is large, the production cycle is as long as 30 to 34 hours, and the process cost is relatively high

[0005] Chinese patent CN101823998 solves the problem of continuous separation of reaction mixture and recycling of reaction raw materials through the coupling of reaction system and simulated moving bed chromatographic separation system. The purity of ethoxyquinoline is increased to more than 98%, but the production cycle of this process is long More than 36 hours, there are also problems such as long production cycle, large amount of solvent consumption, and high process cost

Using p-toluenesulfonic acid as a catalyst to prepare ethoxyquinoline can obtain relatively ideal product yields, but its reaction time is longer and energy consumption is high, resulting in high process costs; using iodine as a catalyst to prepare ethoxyquinoline phenoline, which can realize complete conversion of raw materials in a relatively short period of time, but the amount of iodine is large and expensive, and there are many side reactions at the same time, resulting in low product yield and high process cost

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