A kind of addition method of diuron

Abstract

The invention relates to a novel addition method of diuron. The addition method specifically comprises the following steps: adding 60 percent dimethylamine aqueous solution into a reaction kettle, adding methylbenzene as a solvent, starting a stirrer to uniformly stirring and mixing materials, cooling the reaction kettle to a temperature of -20 DEG C by using an external cycling program-controlledconstant-temperature trough, dropwise adding 3,4-benzene dichloroisocyanate into the reaction kettle by virtue of a dropwise adding tank, uniformly mixing with solvent methylbenzene, controlling thetemperature of the reaction kettle at about 25 DEG C by using the external cycling program-controlled constant-temperature trough, controlling the temperature not to exceed 30 DEG C, reacting for 4 hours, adjusting the pH value to be 7 to 8 by using alkali, heating to 80 DEG C, centrifugally filtering, recycling solvent methylbenzene, washing a filter cake to be neutral, drying at the temperatureof 90 to 100 DEG C, and obtaining the diuron. The purity of the thiophanate-methyl synthesized in the invention reaches 98 percent or above, the reaction conversion rate is 95 percent or above, the safety is good, the temperature is easy to control, the generation of pollutants is reduced, and the byproducts are reduced.

Description

technical field [0001] The invention relates to the technical field of diuron synthesis, in particular to a method for adding diuron. Background technique [0002] Diuron (English name Diuron) is a substituted urea herbicide developed by DuPont Company of the United States. It is derived from the addition of 3,4-dichlorophenylisocyanate and dimethylamine. The reaction equation is as follows: [0003] [0004] Diuron has a systemic conduction effect and a certain contact effect, mainly root absorption. After the weed root system absorbs the pesticide, it spreads to the leaves on the ground and spreads along the veins to the surroundings. It can kill the plants by inhibiting the Hill reaction in photosynthesis, causing the weeds to fade from the tip and edge of the leaves, and finally to the leaves. The whole leaf withers, unable to produce nutrients, and dies of starvation. Diuron is mainly used for cotton, soybean, corn, peanut, sugarcane, fruit tree, tea tree, rubber...

AI Technical Summary

Problems solved by technology

Although this method has a certain improvement compared to adding 3,4-dichlorophenylisocyanate solution dropwise to dimethylamine aqueous solution, because there is still moisture in the system, it has not solved the problem of "causing m-3,4-dichlorophenylisocyanate Hydrolysis reaction with water produces by-product N,N-bis(3,4-dichlorodiphenyl)urea, resulting in low product yield, low content, and difficult separation and purification”

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