	US 12,221,415 B2
	Method for preparing 2,3-dichloro-5-trifluoromethylpyridine with high selectivity
Wanjin Yu, Hangzhou (CN); Shengda Lin, Hangzhou (CN); Minyang Liu, Hangzhou (CN); Wucan Liu, Hangzhou (CN); Jianjun Zhang, Hangzhou (CN); and Xianjin Chen, Hangzhou (CN)
Assigned to ZHEJIANG LANTIAN ENVIRONMENTAL PROTECTION HI-TECH CO., LTD., Hangzhou (CN); ZHEJIANG RESEARCH INSTITUTE OF CHEMICAL INDUSTRY CO., LTD., Zhejiang (CN); and SINOCHEM LANTIAN CO., LTD., Hangzhou (CN)
Filed by Zhejiang Lantian Environmental Protection Hi-Tech Co., Ltd., Hangzhou (CN); Zhejiang Research Institute of Chemical Industry Co., Ltd., Zhejiang (CN); and Sinochem Lantian Co., Ltd., Hangzhou (CN)
Filed on Sep. 17, 2021, as Appl. No. 17/478,129.
Application 17/478,129 is a division of application No. 16/620,763, granted, now 11,186,546, previously published as PCT/CN2018/119312, filed on Dec. 5, 2018.
Claims priority of application No. 201711275197.X (CN), filed on Dec. 6, 2017; application No. 201810009294.2 (CN), filed on May 1, 2018; application No. 201810009301.9 (CN), filed on May 1, 2018; and application No. 201810020465.1 (CN), filed on May 1, 2018.
Prior Publication US 2022/0002249 A1, Jan. 6, 2022
Int. Cl. C07D 213/61 (2006.01)

CPC C07D 213/61 (2013.01)

15 Claims

1. A method for preparing 2,3-dichloro-5-trifluoromethylpyridine, wherein the method comprises:

at a temperature of 100˜150° C. and a pressure of 0.5˜5.0 MPa, in the presence of a first catalyst, 2-chloro-5-trifluoromethylpyridine reacts with chlorine gas to obtain 2,3-dichloro-5-trifluoromethylpyridine;

the first catalyst is supported metal chloride; for the supported metal chloride, its active components are at least one selected from WCl₆, MoCl₅, FeCl₃, AlCl₃, CuCl₂, ZnCl₂, SnCl₄, and SbCl₅, and the loading of the active components is 1-50 wt %;

the 2-chloro-5-trifluoromethylpyridine is prepared by the following steps:

in the presence of a second catalyst, the reaction temperature is maintained at 150˜350° C., and 3-trifluoromethylpyridine reacts with chlorine in gaseous phase, to obtain 2-chloro-5-trifluoromethylpyridine;

the second catalyst is at least one selected from ZSM-5,5A, β and 13X molecular sieve, for the ZSM-5 molecular sieve, its Si/Al ratio is 50˜300, the counter cation is at least one selected from H⁺, Na⁺, K⁺, Ca²⁺.