阅读说明：本技术 一种硝磺草酮的制备方法 (Preparation method of mesotrione ) 是由 张晓臣 李萍 张强 牛巍 于 2019-11-22 设计创作，主要内容包括：本发明公开了一种硝磺草酮的制备方法,包括以下步骤：将100重量份2-硝基-4-甲磺酰基苯甲酰氯溶解在有机溶剂中,加入150～170重量份1,3-环己二酮后均匀滴加150～160重量份吡啶,进行酯化缩合；再加入30～40重量份4-二甲氨基吡啶、2-3重量份四丁基溴化铵以及150～180重量份吡啶的混合液进行重排反应,再加盐酸调至pH为1～2,分液水洗,加水蒸馏以回收二氯甲烷,然后放料、抽滤得粗品磺草酮；趁热将抽滤出的粗品磺草酮投入精制反应釜中,在50～55℃下搅拌20～40分钟,放料后抽滤,母液进甲醇蒸馏釜蒸馏精制以回收甲醇,将固体产物经干燥、气流粉碎后得硝磺草酮成品。该方法提高了产品的收率和纯度,还避免了使用三乙胺造成的水体污染。(The invention discloses a preparation method of mesotrione, which comprises the following steps: dissolving 100 parts by weight of 2-nitro-4-methylsulfonylbenzoyl chloride in an organic solvent, adding 150-170 parts by weight of 1, 3-cyclohexanedione, uniformly dropwise adding 150-160 parts by weight of pyridine, and performing esterification condensation; then adding a mixed solution of 30-40 parts by weight of 4-dimethylaminopyridine, 2-3 parts by weight of tetrabutylammonium bromide and 150-180 parts by weight of pyridine for rearrangement reaction, adding hydrochloric acid to adjust the pH value to 1-2, separating the liquid, washing with water, adding water for distillation to recover dichloromethane, then discharging and carrying out suction filtration to obtain a crude sulcotrione product; and putting the pumped and filtered crude mesotrione into a refining reaction kettle while the mesotrione is hot, stirring for 20-40 minutes at 50-55 ℃, discharging, pumping and filtering, feeding the mother liquor into a methanol distillation kettle, distilling and refining to recover methanol, drying and carrying out jet milling on a solid product to obtain a mesotrione finished product. The method improves the yield and purity of the product, and avoids water pollution caused by triethylamine.)

1. A method for preparing mesotrione, comprising the steps of: dissolving 100 parts by weight of 2-nitro-4-methylsulfonylbenzoyl chloride in an organic solvent, adding 150-170 parts by weight of 1, 3-cyclohexanedione, uniformly dropwise adding 150-160 parts by weight of pyridine, and performing esterification condensation; then adding a mixed solution of 30-40 parts by weight of 4-dimethylaminopyridine, 2-3 parts by weight of phase transfer agent and 150-180 parts by weight of pyridine for rearrangement reaction, adding hydrochloric acid to adjust the pH value to 1-2, separating liquid, washing with water, adding water for distillation to recover dichloromethane, then discharging and carrying out suction filtration to obtain a crude product mesotrione; and putting the pumped and filtered crude mesotrione into a refining reaction kettle while the mesotrione is hot, stirring for 20-40 minutes at 50-55 ℃, discharging, pumping and filtering, feeding the mother liquor into a methanol distillation kettle, distilling and refining to recover methanol, drying and carrying out jet milling on a solid product to obtain a mesotrione finished product.

2. The process for preparing mesotrione according to claim 1, wherein: the organic solvent is dichloromethane.

3. The process for preparing mesotrione according to claim 1, wherein: the phase transfer agent is tetrabutylammonium bromide.

4. The process for preparing mesotrione according to claim 1, wherein: the temperature of esterification condensation is 15-40 ℃, and the time is 60-80 minutes.

5. The process for preparing mesotrione according to claim 1, wherein: the temperature of the rearrangement reaction was 50 ℃ for 30 minutes.

Technical Field

The invention belongs to the field of organic chemistry, and particularly relates to a preparation method of mesotrione.

Background

The mesotrione is targeted at the action of p-hydroxyphenyl pyruvate dioxygenase (HPPD), is mainly used for preventing and removing broadleaf weeds and grassy weeds in corn fields, has the characteristics of wide weeding spectrum, good environmental compatibility, low toxicity to mammals and aquatic organisms, safety to corn, no phytotoxicity to succeeding crop rotation crops and the like, and has great market demand and good application prospect. In addition, mesotrione is particularly effective against triazobenzene and sulfonylurea resistant weeds, and there is no cross-resistance between the weeds and these types of herbicides, which provides convenience in herbicide selection in crop rotation. In the production process of mesotrione, a large amount of alkaline organic wastewater is generated, and the alkaline organic wastewater contains a large amount of triethylamine, so that the alkaline organic wastewater can cause serious influence on fishes and shrimps in a river if the alkaline organic wastewater is directly discharged into the river.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a preparation method of mesotrione, which avoids environmental pollution caused by triethylamine and simultaneously improves the purity and yield of the product.

The technical scheme provided by the invention is as follows:

a process for the preparation of mesotrione, comprising the steps of:

dissolving 100 parts by weight of 2-nitro-4-methylsulfonylbenzoyl chloride in an organic solvent, adding 150-170 parts by weight of 1, 3-cyclohexanedione, and uniformly dropwise adding 160 parts by weight of pyridine to perform esterification condensation; then adding a mixed solution of 30-40 parts by weight of 4-dimethylaminopyridine, 2-3 parts by weight of tetrabutylammonium bromide and 150-180 parts by weight of pyridine for rearrangement reaction, adding hydrochloric acid to adjust the pH value to 1-2, separating liquid, washing with water, adding water for distillation to recover dichloromethane, then discharging, and carrying out suction filtration to obtain a crude sulcotrione product; and putting the pumped and filtered crude mesotrione into a refining reaction kettle while the mesotrione is hot, stirring for 20-40 minutes at 50-55 ℃, discharging, pumping and filtering, feeding the mother liquor into a methanol distillation kettle, distilling and refining to recover methanol, drying and carrying out jet milling on a solid product to obtain a mesotrione finished product.

On the basis of the technical scheme, the organic solvent is dichloromethane.

On the basis of the technical scheme, the phase transfer agent is tetrabutylammonium bromide.

On the basis of the technical scheme, the temperature of esterification condensation is 15-40 ℃, and the time is 60-80 minutes.

On the basis of the technical scheme, the temperature of the rearrangement reaction is 50 ℃, the esterification condensation time is 30 minutes and is 15-40 ℃, and the esterification condensation time is 60-80 minutes.

Compared with the prior art, the invention has the following advantages and beneficial effects:

(1) the invention adopts alkalescent pyridine to replace the traditional triethylamine, the pyridine reacts with the byproduct HCl of 2-nitryl-4-mesylbenzoyl chloride and 1, 3-cyclohexanedione to generate the hydrochloride salt which is not easy to volatilize, the gas pollution caused by using triethylamine is avoided, the pyridine hydrochloride has wide application range, can be directly sold, and is easy to recover and become the pyridine.

(2) The invention adopts 4-dimethylamino pyridine and tetrabutyl ammonium bromide to replace virulent acetone cyanohydrin as the catalyst, thereby improving the safety of production.

(3) The yield of the invention can reach more than 91 percent, and is improved by 3 percent compared with the prior art.

Detailed Description

The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. The reagents and raw materials used are commercially available unless otherwise specified. The experimental methods without specifying specific conditions in the following examples were selected according to the conventional methods and conditions, or according to the commercial instructions.