Preparation for 6-chlorine-2-trichloromethyl pyridine

Abstract

The invention discloses a method for preparing 6-chloro-2-trichloromethyl pyridine. The method includes the steps as follows: gaseous chlorine and 2-methylpyridine are adopted as the raw materials; initiator is added to a first reactor, and excessive gaseous chlorine is introduced into the reactor; the gaseous chlorine and the initiator react to produce HCl gas which rises into a second reactor, and is in convection with 2-methylpyridine to produce 2-methylpyridine hydrochloride under a temperature-control condition; the hydrochloride returns to the first reactor and reacts with the excessive gaseous chlorine to produce 2-trichloromethylpyridine which reacts with continuously-introduced excessive gaseous chlorine at a certain temperature until the reaction reaches a stable state to obtain a volatile 6-chloro-2-trichloromethyl pyridine enriched mixture; the mixture is extracted from the kettle bottom and refined to obtain 6-chloro-2-trichloromethyl pyridine compound; and a tail-gas recovery device is connected with the second reactor. The method has the advantages of high selectivity, high yield and environment friendliness.

Description

technical field [0001] The invention relates to a preparation method of 6-chloro-2-trichloromethylpyridine. Background technique [0002] Because 6-chloro-2-trichloromethylpyridine can be used as an intermediate of medicine and pesticides, especially in the field of fertilizers, it can be used to improve agricultural nitrogen fertilizer, delay the nitrification of NH4+, and improve soil and plant nutrition. . Therefore, people wish to find a high-efficiency preparation method. The methods for preparing 6-chloro-2-trichloromethylpyridine-enriched mixtures reported in the past include: the patent No. is US3424754, the patent name is "Preparation of 2-chloro-6-trichloromethylpyridine" and the patent No. It is US3420833, and the patent name is "Production of Polychlorinated Pyridine Compounds by Gas Phase Method". The patent No. is US3424754 by passing 2-picoline hydrochloride into chlorine gas, reacting at 200°C to obtain a 75% volatile mixture containing 90% 6-chloro-2-tric...

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Problems solved by technology

Although the patent No. is US4577027, the patent name is that the method introduced in "2-picoline direct liquid-phase chlorination method to produce polychlorinated pyridine mixture" is different from the methods in these documents in the past, but the patent No. is that US4577027 introduces in 100-250°C, at CCL 4 The reaction of chlorine with 2-picoline in the presence of a diluent is also impractical to obtain a mixture enriched in 6-chloro-2-trichloropicoline, which has many by-products, diluent CCL 4 A large amount of loss will cause great harm to the atmospheric environment, and after 2010 CCL 4 It will be banned from production and use, and it is also difficult to industrialize the method

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