METHOD FOR PREPARING 2,6-DICHLOROPYRIDINE THROUGH LIQUID PHASE PHOTOCHLORINATION OF PYRIDINE
First Claim
1. A method for preparing 2,6-dichloropyridine through liquid phase photochlorination of pyridine, wherein pyridine and chlorine gas are enabled to continuously experience chlorination reaction at temperature of 150-210°
- C. under irradiation of ultraviolet light by using pyridine and chlorine gas as starting materials and using trifluoromethyl chlorobenzene as a solvent, and a chlorination reaction product and the solvent are cooled to obtain pyridine chlorination solution.
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Abstract
The present invention relates to a method for preparing 2,6-dichloropyridine with product purity greater than or equal to 99.0% by using trifluoromethyl chlorobenzene as a solvent for reaction between pyridine and chlorine gas. The preparation process comprises the following steps: enabling pyridine and chlorine gas to continuously experience chlorination reaction under irradiation of ultraviolet light by using pyridine and chlorine gas as starting materials and using trifluoromethyl chlorobenzene as a solvent, and cooling a chlorination reaction product and the solvent to obtain pyridine chlorination solution. Advantages: firstly, it pioneers the precedent of direct and high-selectivity preparation of 2,6-dichloropyridine through liquid phase photochlorination, and not only can the 2,6-dichloropyridine product with purity greater than or equal to 99.0% be obtained, but also industrial production is facilitated; and secondly, not only can the reuse of the separated solvent in the preparation process of the 2,6-dichloropyridine product with purity greater than or equal to 99.0% be realized, but also the purposes of low pollution, low energy consumption and low cost in the preparation process can be realized.
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9 Claims
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1. A method for preparing 2,6-dichloropyridine through liquid phase photochlorination of pyridine, wherein pyridine and chlorine gas are enabled to continuously experience chlorination reaction at temperature of 150-210°
- C. under irradiation of ultraviolet light by using pyridine and chlorine gas as starting materials and using trifluoromethyl chlorobenzene as a solvent, and a chlorination reaction product and the solvent are cooled to obtain pyridine chlorination solution.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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