Sinochem Lantian Co., Ltd.

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

Zhejiang Research Institute of Chemical Industry Co., Ltd.

Advanced New Technologies Co., Ltd.

Jianjun Zhang

Wucan Liu

Wanjin Yu

Shengda Lin

Minyang Liu

Xianjin Chen

Yawen Wei

Zhiwei Wang

Shucheng Wang

Wenfeng Han

Feixiang Zhou

Zhanqi Bai

Deqiang Ran

Yan Pan

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

Disclosed is a method for reducing carbon deposits on a catalyst in recycling HFC-23. The recycling is realized by means of a fluorine-chlorine exchange reaction with HFC-23 and a halogenated hydrocarbon. The catalyst for the fluorine-chlorine exchange reaction comprises a main body catalyst and a precious metal. The precious metal is selected from at least one of Pt, Pd, Ru, Au or Rh, and has an addition amount of 0.01-2 wt %. During the fluorine-chlorine exchange reaction, hydrogen gas is introduced. The invention has advantages of good catalyst stability, long life, etc.

Method for reducing carbon deposits on catalyst in recycling HFC-23

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.

Disclosed herein are methods, systems, and apparatus for cross-chain authentication. One of the methods includes: obtaining an identity confirmation request and a first public key; obtaining an identity verification request and a corresponding identity verification identifier for identity verification of a user associated with the user terminal; sending the identity verification request and the first public key to the user terminal; obtaining digitally signed data, a second public key, and identity verification data; verifying an identity of the user based on the identity verification data; verifying that the first public key and the second public key correspond to the user; and recording authentication data comprising the digitally signed data and the identity verification identifier to a blockchain.

Cross-chain authentication method, system, server, and computer-readable storage medium

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Hangzhou, China

Jianjun Zhang