Process method for preparing o-ethoxy benzoyl chloride

Abstract

The invention discloses a process method for preparing o-ethoxy benzoyl chloride. The method comprises the following steps: (1) ethylation reaction, (2) alkaline hydrolysis reaction and (3) acylatingchlorination reaction. Cheap and easily available methyl salicylate is used as a starting material, diethyl sulfate, which is low in price and easy to control, is used as an ethylation reagent, the reaction steps are simple, the operability is high, the reaction conditions are mild, the process is simple, and the method is an industrial production method easy to control. The acylating chlorinationreaction is carried out by adopting solid phosgene with a good acylating chlorination effect, the use is convenient, and the generated by-products HCl and CO2 are gas and can be conveniently separated from the product; a catalyst, which can be repeatedly used, is used in the acylating chlorination reaction process, so that the aims of saving energy and saving cost are fulfilled; and the method issimple in process, convenient to operate, low in raw material cost, high in yield, good in quality and convenient for industrial production.

Description

technical field [0001] The invention relates to the technical field of pharmaceutical intermediates, in particular to a process for preparing o-ethoxybenzoyl chloride. Background technique [0002] Acid chloride is an important carboxylic acid derivative, which has important applications in organic synthesis and drug synthesis. It can mainly undergo various reactions such as hydrolysis, aminolysis, alcoholysis, actual reaction with organometallics, and reduction reaction. It is the most active acylating reagent. The most commonly used methods for preparing acid chlorides are thionyl chloride method, phosphorus trichloride method, phosphorus pentachloride method, phosphorus oxychloride method, carbon tetrachloride method, oxalyl chloride method, Phosgene method, double phosgene method and three phosgene method. [0003] O-ethoxybenzoyl chloride is an organic compound used in pharmaceutical intermediates and organic synthesis. It is an important intermediate for the preparati...

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Problems solved by technology

[0004] The synthetic method of o-ethoxybenzoyl chloride reported in the literature mainly comprises two kinds at present: a kind of is to be starting raw material with methyl salicylate, make with iodoethane or bromoethane as ethylating reagent reaction Methyl o-ethoxybenzoate, then hydrolyzed and acidified to obtain o-ethoxybenzoic acid, and finally o-ethoxybenzoyl chloride was obtained by the thionyl chloride method; thionyl chloride has a strong pungent smell, which is harmful to The human body is more harmful, and the excessive thionyl chloride is easily hydrolyzed to generate sulfur dioxide and hydrogen chloride during the process of reapplying, polluting the environment

The other is to use salicylic acid as the starting material, under the catalysis of 18-crown-6 or benzyltriethylammonium chloride, directly react with bromoethane to prepare o-ethoxybenzoic acid, and then pass through phosgene O-ethoxybenzoyl chloride can be obtained by the phosgene method; the catalysts for the preparation of acid chloride by the phosgene method are mainly amides such as dimethylformamide or ureas, tertiary amines such as triethylamine, organic phosphines such as triphenylphosphine, and Lewis acids etc., the dosage is generally 2-10% of the raw material acid mass, the above-mentioned amine and amide catalysts are used in a large amount, it is difficult to separate from the product acid chloride, the denaturation due to moisture absorption after use cannot be applied mechanically, the production capacity is low, and the solid waste generated is more. , and phosgene adducts are prone to explosion in water and other dangerous and unfavorable factors; organic phosphine catalysts by-product phosphine oxides, and the country has strict control indicators for the discharge of phosphine-containing wastes

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