Preparation of bactericide propiconazole

Abstract

The invention discloses a preparation method of propiconazole that is a bactericide, which comprises four steps: first of all, under the action of an acid catalyst, atmospheric refluxing dehydration is carried out to 2, 4-dichloroacetophenone and 1, 2-pentanediol which are in an organic solvent so as to obtain ketal reaction solution which then reacts with bromine to generate bromide ketal which then reacts with 1, 2, 4- triazole sylvite in a polar solvent under the action of a phase transfer catalyst to obtain a propiconazole crude product; finally, under the action of an antioxidant, the propiconazole crude product is distilled under high vacuum and high temperature to obtain the propiconazole finished product. The preparation method of the invention reduces the varieties and dosage of the solvents necessary for reactions as well as the yield of wastewater resulted from cleaning during the reactions, thus realizing the goal of clean production.

Description

technical field [0001] The invention relates to an agricultural fungicide, in particular to a preparation method of propiconazole. Background technique [0002] Propiconazole is 1-[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolane-2-methyl]-1-hydrogen-1,2,4- Generic name for triazole. It is a systemic triazole fungicide with protective and therapeutic effects, which can be absorbed by roots, stems, and leaves, and can quickly conduct upwards in the plant to prevent and control ascomycetes, basidiomycetes, and half-knowledge fungi. It has a good control effect on wheat take-all, powdery mildew, rust, root rot, rice bad fungus, and banana leaf spot. [0003] U.S. Patent US4079062 (1979) application document discloses the synthetic method of series compounds such as propiconazole, and wherein propiconazole adopts 2,4-dichlorophenyl-alpha-bromomethyl ketone as starting raw material, through and 1 , 2-pentanediol is cyclized to obtain bromoketal, and then condensed with 1,2,4-tria...

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Problems solved by technology

[0004] The weak point of above-mentioned patent method is: (1) in the preparation process of starting material 2,4-dichlorophenyl-alpha-bromomethyl ketone, be difficult to reach ideal quality and yield, main reason is that there is 8% of 2,4-dichlorophenyl-α, the by-product of α-dibromomethyl ketone, and 6% of 2,4-dichloroacetophenone can not react, resulting in purification and separation difficulties, thus greatly Affected the content of propiconazole crude product

In the process of salt formation and neutralization reaction, a large amount of organic solvents are needed, which will be lost in the process of recycling organic solvents, which will easily cause air pollution

In addition, during the washing process, a large amount of sodium nitrate-containing wastewater is generated, which is difficult to treat and discharge up to the standard

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