Sinochem Lantian Co., Ltd.

Zhejiang Lantian Environmental Protection Hi-tech Co., Ltd.

Zhejiang Research Institute of Chemical Industry Co., Ltd.

Wanjin Yu

Wucan Liu

Jianjun Zhang

Shengda Lin

Minyang Liu

Xianjin Chen

A method for preparing 2,3-dichloro-5-trifluoromethylpyridine, comprising at a temperature of 100˜150° C. and a pressure of 0.5˜5.0 MP, in presence of at least one catalyst selected from supported metal chloride, supported zeolite molecular sieve and supported heteropolyacid, 2-chloro-5-trifluoromethylpyridine reacts with chlorine gas to obtain 2,3-dichloro-5-trifluoromethylpyridine. The preparing method provided by the present invention has advantages such as high selectivity of desired product, high utilization rate of chlorine gas, moderate process condition, simple operation and less three wastes. The present invention also discloses a preparing method for preparing 2-chloro-5-trifluoromethylpyridine, which is capable of reducing unit consumption, reducing separation cost, and improving safety compared to the prior art.

Method for preparing 2,3-dichloro-5-trifluoromethylpyridine with high selectivity

The present invention provides a method for the preparing of 2-chloro-5-trifluoromethylpyridine, comprising two steps of chlorofluorination reaction and chlorination reaction, the chlorination catalyst used in the chlorination reaction was chosen from a fluoride, an oxide, a hydroxide, a carbonate, or a chloride of magnesium, calcium and barium and a supported palladium catalyst; or under the action of at least one catalyst chosen from ZSM-5, 5A, &#x3b2; and 13&#xd7; molecular sieves, 3-trifluoromethylpyridine and chlorine gas phase have reaction to obtain 2-chloro-5-trifluoromethylpyridine. Or, under the action of a catalyst chosen from a fluoride, an oxide, a hydroxide, a carbonate, or a chloride of magnesium, calcium, and barium and a supported palladium catalyst, 3-trifluoromethylpyridine and chlorine gas phase have reaction to obtain 2-chloro-5-trifluoromethylpyridine. The present invention has the advantages of easily availability and low-cost of raw materials, safe operation, high yield, easy isolation and recovery of catalyst, environmental protection, fast reaction speed and continuous production on a large-scale, etc.

Method for preparing 2-chloro-5-trifluoromethylpyridine

The present invention discloses a method for preparing 2,3-dichloro-5-trifluoromethylpyridine, comprising at a temperature of 100&#x2dc;150&#xb0; C. and a pressure of 0.5&#x2dc;5.0 MP, in presence of at least one catalyst selected from supported metal chloride, supported zeolite molecular sieve and supported heteropolyacid, 2-chloro-5-trifluoromethylpyridine reacts with chlorine gas to obtain 2,3-dichloro-5-trifluoromethylpyridine. The preparing method provided by the present invention has advantages such as high selectivity of desired product, high utilization rate of chlorine gas, moderate process condition, simple operation and less three wastes. The present invention also discloses a preparing method for preparing 2-chloro-5-trifluoromethylpyridine, which is capable of reducing unit consumption, reducing separation cost, and improving safety compared to the prior art.

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Zhejiang, China

Wanjin Yu