The Synthesis of 2, 3, 5-trichloropyridine and 2, 3-difluoro-5-chloropyridine
|Keywords||2,3,5 - Trichloropyridine 2,3 - Difluoro-5 - chloropyridine Preparation Fluorinated|
This paper mainly studies an important pesticide intermediate 2,3,5 cross-linked with pyridine and 2, 3-2 fluoro - 5 - chloro pyridine synthesis, they can be widely used to synthesize a weeding or insecticidal activity compounds. In the process of synthesis of high-intensity,3,5 - pyridine 2, the two synthetic methods were studied. The first method is based on five chlorine pyridine as raw material, under certain conditions, products made by reaction with zinc powder of high-intensity,3,5 - pyridine, 2 dosage of zinc powder, alkali concentration, reaction temperature, reaction time, the factors influencing post-processing methods, etc. The second method is based on chloral and acrylonitrile as raw material, under the effect of catalyst, the preparation of high-intensity,3,5 - pyridine, 2 examines the material ratio, operation mode, reaction temperature, reaction time, catalyst, etc factors. Fluorine in synthesis of 2, 3 - two - five - in the process of chlorine pyridine, mainly studied the halogen exchange fluorination method. Reaction with 2,3,5 - cross-linked with pyridine as raw material, using a mixture of KF and CsF for fluoride, in a certain reaction under the condition of the preparation of product 2, 3 - two fluorine - 5 - chloro pyridine. Reaction temperature, reaction time, mode of operation, the factors influencing reaction solvents, catalysts, etc.