Preparation method of trichloropyridine

A technology for trichloropyridine and chloropyridine, which is applied in the field of preparation of 2,3,6-trichloropyridine, can solve the problems of many wastes, complicated product separation process, residual residues and the like

Active Publication Date: 2014-04-23
盐城恒盛化工有限公司
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  • Abstract
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Problems solved by technology

[0008] The object of the present invention is to overcome the product separation process complexity existing in the existing triclopyridine preparation method, waste material is many, residual catalyst such as

Method used

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Examples

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Example Embodiment

[0016] The present invention provides a method for preparing trichloropyridine. The method comprises: contacting and reacting low-chlorinated pyridine compounds with chlorine gas in the presence of a catalyst to obtain a product after the contact reaction, wherein the catalyst is ferric chloride, One or more of zinc chloride, magnesium chloride and aluminum chloride are distilled after passing inactive gas into the product after the contact reaction.

[0017] According to the present invention, the catalyst is a catalyst commonly used in the art to synthesize trichloropyridine by contacting low-chlorinated pyridine compounds with chlorine gas. As such a catalyst, one or more of the aforementioned ferric chloride, zinc chloride, magnesium chloride, and aluminum chloride; from the viewpoint of cost performance, the catalyst is preferably ferric chloride. The catalysts of the present invention are all Lewis acids of metal chlorides. This catalyst can form a complex with chlorine in ...

Example Embodiment

[0034] Example 1

[0035] This example is used to illustrate the preparation method of 2,3,6-trichloropyridine of the present invention.

[0036] 15g of ferric chloride and 350g of 2,6-dichloropyridine were mixed, heated to 200°C under a nitrogen atmosphere, and then reacted with chlorine gas for 8 hours to obtain the product after the contact reaction. The product after the contact reaction contained 389g 2,3,6-trichloropyridine, 17.3g of 2,6-dichloropyridine and 15.5g of 2,3,5,6-tetrachloropyridine.

[0037] The product was bubbled with nitrogen gas at 200°C for 2h, then cooled to 140°C, and distilled under the condition of a vacuum of 0.095MPa. The fraction with a temperature of 132-138°C was collected to obtain 412g of the fraction. The contents of 2,3,6-trichloropyridine, 2,6-dichloropyridine and 2,3,5,6-tetrachloropyridine contained in the pyridine are respectively 92.7% by weight, 4.04% by weight and 3.26% by weight, 2. The distillation yield of 3,6-trichloropyridine was 97....

Example Embodiment

[0041] Example 2

[0042] This example is used to illustrate the preparation method of 2,3,6-trichloropyridine of the present invention.

[0043] 100g of 2,6-dichloropyridine prepared by the method of Example 1 and chlorine gas were contacted with the product material after the reaction. At 200°C, nitrogen gas was introduced for bubbling for 1h, and then the temperature was lowered to 140°C. Distillation was carried out under the condition of 0.085MPa, and the fraction with a temperature of 160-165°C was collected to obtain a fraction 90.1g. The fraction contained 2,3,6-trichloropyridine, 2,6-dichloropyridine and 2,3, The content of 5,6-tetrachloropyridine was 93.2% by weight, 3.75% by weight, and 2.96% by weight, respectively, and the distillation yield of 2,3,6-trichloropyridine was 94.3%.

[0044] Take 0.12g of the above-mentioned fractions for digestion, and mix the digestion product into a 25ml solution for ICP analysis. The measured iron ion concentration is 0.0210mg / L, which ...

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Abstract

The invention discloses a preparation method of trichloropyridine. The method comprises the following steps: enabling a low chlorinated pyridine compound to react with chlorine in a contact manner in the existence of a catalyst, so as to obtain a contact reaction product, wherein the catalyst is one or more of ferric chloride, zinc chloride, magnesium chloride and aluminum chloride; and leading in an inactive gas to the contact reaction product to distill. By adopting the method disclosed by the invention, the distillation yield of the trichloropyridine can be up to over 90%, and the obtained product trichloropyridine does not contain a catalyst ingredient. In addition, the distilled residue can be applied to catalyzed synthesis of the trichloropyridine.

Description

technical field [0001] The invention relates to a preparation method of trichloropyridine, in particular to a preparation method of 2,3,6-trichloropyridine. Background technique [0002] 2,3,6-Trichloropyridine (hereinafter referred to as three CP) is an important pharmaceutical and pesticide intermediate. For example, in pesticide chemistry, 2,3,6-trichloropyridine is mainly used to synthesize new insecticides chlorantraniliprole and cyantraniliprole. In the synthetic method of 2,3,6-trichloropyridine, it is currently widely used to use 2,6-dichloropyridine as a raw material, and 2,6-dichloropyridine is chlorinated by chlorine gas through the catalysis of Lewis acid Three CPs are obtained, wherein, the commonly used Lewis acids of metal chlorides are used as catalysts, such as ferric chloride, zinc chloride, aluminum chloride, etc., and ferric chloride is preferably used. This method has the advantages of simple process, low cost and high yield. [0003] For example, in ...

Claims

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Application Information

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IPC IPC(8): C07D213/61
CPCC07D213/61
Inventor 张小航李勇李季
Owner 盐城恒盛化工有限公司
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