Preparation method of 1-isopropyl-3-tert-butylthiourea

Abstract

The invention discloses a preparation method of 1-isopropyl-3-tert-butylthiourea. Ammonium thiocyanate, tert-butyl alcohol and hydrochloric acid serve as raw materials and conduct the substitution reaction to generate a mixture of thiocyanic acid tert-butyl ester and isothiocyanic acid tert-butyl ester, the mixture stands still and is layered, water in the mixture is removed, then concentrated sulfuric acid serves as a transposition catalyst, thiocyanic acid tert-butyl ester is transposed to generate isothiocyanic acid tert-butyl ester, finally under the existence of isopropylamine, water serves as a solvent, the addition reaction is conducted, and a target product is synthesized. Water is removed in the reaction based on the principle that the specific gravity of matter is reduced to different degrees along with increase of temperature, and a large amount of heat energy is saved; the sulfuric acid serves as the transposition catalyst, and the reaction yield is increased to more than 90% from about 66% originally; the water serves as the solvent, risks are reduced in the production process of a production workshop, operation is safer, environment friendliness is achieved, cost is low, and quality is high; the total reaction yield of the method can be more than 88.9% by ammonium thiocyanate, and the method is more suitable for industrial production.

Description

[0001] technical field [0002] The invention relates to a preparation method of a pesticide intermediate, in particular to a preparation method of 1-isopropyl-3-tert-butylthiourea. Background technique [0003] 1-isopropyl-3-tert-butylthiourea is a key intermediate for the preparation of the insect growth regulator Buprofezin. The chemical name of Buprofezin is 2-tert-butylimino-3-isopropyl-5- Phenyl-1,3,5-thiadiazin-4-one is a thiadiazine insect growth regulator and belongs to insect molting inhibitor. By inhibiting the synthesis of chitin and interfering with metabolism, the pests cannot molt and metamorphosis normally and gradually die. It has the characteristics of high activity, high selectivity and long residual period. It is a chitin synthesis inhibitor of heterocyclic insects that does not kill adults, but can reduce oviposition and hinder egg hatching. Buprofezin is an agricultural insecticide with persistent larvicidal activity against Coleoptera, some Homopter...

AI Technical Summary

Problems solved by technology

[0006] At present, manufacturers of buprofezin use reflux to carry water when producing tert-butyl isocyanate. The disadvantage is that anhydrous zinc chloride and aluminum trichloride are used in the production of tert-butyl isocyanate. If the flocculant is converted into a catalyst, it is easy to generate waste residue, which affects the reaction yield and efficiency

Most of the solvents for synthesizing 1-isopropyl-3-tert-butylthiourea use toluene, 1,2-dichloroethane or mineral spirits, and toluene is a precursor chemical, and the vapor pressures of these solvents are all It is relatively high and is flammable, so it is easy to cause production safety accidents, and it also brings difficulties to the treatment of three wastes

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