阅读说明：本技术 一种氟乐灵原药的合成方法 (Method for synthesizing trifluralin technical material ) 是由 郑龙生 方东 张亮 李付香 于 2018-07-02 设计创作，主要内容包括：本发明公开了一种氟乐灵原药的合成方法。以对氯二硝三氟甲苯、二正丙胺为原料,烧碱为催化剂,水为反应介质,反应结束后水洗、重结晶、离心、真空烘干后即得氟乐灵(2,6-二硝基-N,N-二正丙基-4-三氟甲基苯胺)成品。本发明与现有技术相比,(1)所用原料、催化剂、溶剂来源广泛,制备方便；(2)烧碱有效地促进反应进行,原料转化率高、产品选择性好,合成反应转化率高于99%,产品纯度99wt%；(3)制备工艺对设备要求低,无需增加特殊设备；(4)反应过程中三废排放较低,环境友好；(5)乙醇重结晶,后处理方便,是一种环境友好的氟乐灵的合成方法,有利于规模工业化发展。(The invention discloses a method for synthesizing a trifluralin original drug. Taking parachlorodinitrilo benzotrifluoride and di-N-propylamine as raw materials, caustic soda as a catalyst and water as a reaction medium, and after the reaction is finished, washing, recrystallizing, centrifuging and drying in vacuum to obtain the finished product of the trifluralin (2, 6-dinitro-N, N-di-N-propyl-4-trifluoromethylaniline). Compared with the prior art, the invention has the advantages that (1) the raw materials, the catalyst and the solvent are wide in source and convenient to prepare; (2) the caustic soda effectively promotes the reaction to be carried out, the conversion rate of the raw materials is high, the selectivity of the product is good, the conversion rate of the synthetic reaction is higher than 99 percent, and the purity of the product is 99 percent by weight; (3) the preparation process has low requirement on equipment, and no special equipment is required to be added; (4) the discharge of three wastes in the reaction process is low, and the method is environment-friendly; (5) the ethanol is recrystallized, the post-treatment is convenient, and the method is an environment-friendly method for synthesizing trifluralin and is beneficial to large-scale industrial development.)

1. A method for synthesizing a trifluralin technical material is characterized by comprising the following steps: taking parachlorodinitrilo benzotrifluoride and di-n-propylamine as raw materials, taking caustic soda as a catalyst and water as a reaction medium, heating, stirring and reacting for a period of time, washing for 2 times after the reaction is finished, recrystallizing with ethanol, centrifuging, and drying in vacuum to obtain a trifluralin finished product, wherein the reaction is shown as a formula (I):

2. The method for synthesizing trifluralin technical material according to claim 1, which is characterized in that: the molar ratio of materials is p-chlorodinitrobenzotrifluoride: di-n-propylamine: caustic soda = 1: 1: 1.

3. the method for synthesizing trifluralin technical material according to claim 1, wherein the reaction temperature is 85 ~ 90 ℃.

4. The method for synthesizing trifluralin technical material according to claim 1, which is characterized in that: the reaction time is 5.0-6.0 hours.

Technical Field

The invention relates to a method for synthesizing a trifluralin original drug, and belongs to the technical field of chemical material preparation. The method is suitable for the occasions of preparing target compounds by heating and stirring reaction by taking parachlorodinitrilo benzotrifluoride and di-n-propylamine as raw materials, caustic soda as a catalyst and water as a reaction medium.

Background

Trifluralin (chemical name: 2, 6-dinitro-N, N-di-N-propyl-4-trifluoromethyl aniline) is an orange crystal, has a melting point of 48.5-49 ℃, is easy to volatilize and photolyze, has extremely small hydrosolvent, and is not easy to move in a soil layer. Is a selective pre-emergence soil treatment agent and is mainly absorbed by coleoptiles and hypocotyls of weeds. Has no effect on emerged weeds, is effective on gramineae and broad-leaved weeds of partial small-grain seeds, and has long efficacy duration. The medicine has low toxicity to human and livestock, and the acute oral administration of LD50 of rat is more than 10000 mg/kg. The herbicide composition is suitable for crops such as cotton, soybean, rape, peanut, potato, winter wheat, barley, sunflower, carrot, sugarcane, tomato, eggplant, hot pepper, cabbage, celery, orchard, mulberry field, melon and the like, and can be used for preventing and killing 1-year gramineae and part of broadleaf weeds such as barnyard grass, crabgrass, goosegrass, sorghum bicolor, moleplant seed, teff grass, bluegrass, brome, duramen, club grass, amaranth, gooseberry, purslane, chickweed, polygonum, morningglory, tribulus terrestris and the like.

At present, a plurality of methods for preparing trifluralin are reported, the content of the trifluralin is usually lower than 93% in the production process, the amination yield is lower than 92%, and the preparation of the trifluralin comprises five raw materials: 1) the p-chlorotoluene is used as a raw material, and a target compound is obtained through chlorination, fluorination, nitration and amination; 2) the method comprises the following steps of (1) performing chlorination, nitration, fluorination and amination on p-aminobenzoic acid serving as a raw material to obtain a target compound; 3) p-hydroxybenzoic acid is used as a raw material, and a target compound is obtained through nitration, chlorination, fluorination and amination (pesticide, 1987, 5: 5-7); 4) substituting aniline as a raw material, and performing nitration reaction in a microreactor to synthesize a target compound (CN 102786423A) in one step; 5) 3, 5-dinitro-4-chloro-benzotrifluoride is used as a raw material, and the trifluralin is synthesized by one step through amination reaction. The method has the main defects of more byproducts in the synthesis process, difficult purification of intermediates, high cost of some fluorinating agents and difficult control of the process. Some methods have long synthesis time and large energy consumption, generate a large amount of three wastes in production and are harmful to the environment.

Disclosure of Invention

The invention aims to provide a novel synthesis process of a trifluralin original drug.

The technical solution for realizing the invention is as follows: taking parachlorodinitrilo trifluorotoluene and di-N-propylamine as raw materials, taking caustic soda as a catalyst and water as a reaction medium, heating, stirring and reacting for a period of time, washing for 2 times after the reaction is finished, recrystallizing with ethanol, centrifuging, and drying in vacuum to obtain the finished product of the trifluralin (2, 6-dinitro-N, N-di-N-propyl-4-trifluoromethylaniline).

The raw materials, alkali, solvent and the like used in the present invention are commercially available raw materials.

The molar ratio of the materials used in the invention is p-chlorodinitrobenzotrifluoride: di-n-propylamine: caustic soda = 1: 1: 1.

the temperature of the reaction of the present invention was 85 ~ 90 ℃.

The reaction time of the present invention was 5.0 ~ 6.0.0 hours.

After the reaction is finished, the reaction product is cooled to room temperature to precipitate crystals, and after the reaction product is kept stand for a period of time, the reaction product is filtered and washed for 2 times, and then is recrystallized by ethanol, centrifuged and dried in vacuum to obtain the finished product of the 2, 6-dinitro-N, N-di-N-propyl-4-trifluoromethyl aniline (trifluralin).

The chemical reaction principle on which the invention is based is as follows:

according to the novel method for the trifluralin technical grade, the technical key point is that the caustic soda is used as an acid-binding agent to promote the reaction, so that the conversion rate and the selectivity are improved; secondly, ethanol is used for recrystallization, so that impurities such as nitrosamine generated by side reaction can be effectively removed. Compared with the prior art, the invention has the advantages that: (1) the raw materials, the catalyst and the solvent are wide in source and convenient to prepare; (2) the caustic soda effectively promotes the reaction to be carried out, the conversion rate of the raw materials is high, the selectivity of the product is good, the conversion rate of the synthetic reaction is higher than 99 percent, and the purity of the product is 99 percent by weight; (3) the preparation process has low requirement on equipment, and no special equipment is required to be added; (4) the discharge of three wastes in the reaction process is low, and the method is environment-friendly; (5) the ethanol is recrystallized, the post-treatment is convenient, and the method is an environment-friendly method for synthesizing trifluralin and is beneficial to large-scale industrial development.

Detailed Description

The following examples further illustrate the invention in order to provide a better understanding of the invention. The examples do not limit the scope of the invention in any way. Modifications and adaptations of the present invention within the scope of the claims may occur to those skilled in the art and are intended to be within the scope and spirit of the present invention.