Method for continuously synthesizing isoproturon

Abstract

The invention discloses a method for continuously synthesizing isoproturon. The method comprises the steps of: taking isopropylaniline as an initial raw material, carrying continuous kettle type phosgenation reaction on isopropylaniline with phosgene, then performing continuous thermal decomposition to obtain isopropylphenyl isocyanate, and carrying out kettle type continuous amination reaction onisopropylphenyl isocyanate and dimethylamine to obtain the product isoproturon. According to the invention, continuous production of isopropylphenyl isocyanate is achieved, and continuous tower-typethermal decomposition and light driving are adopted to replace kettle-type light driving, so that nitrogen is saved, and the operation machine hour is reduced; unreacted phosgene is pumped into the photochemical kettle again for reaction after being cooled, separated and absorbed by methylbenzene, so that the phosgene utilization rate is increased, and the phosgene tail gas treatment cost is reduced; and continuous automatic operation of isoproturon synthesis is achieved.

Description

technical field [0001] The invention relates to a method for synthesizing isoproturon. Background technique [0002] Isoproturon, whose chemical name is N-(4-isopropylphenyl)-N’,N’dimethylurea, is a high-efficiency and low-toxicity substituted urea herbicide. It has the characteristics of wide herbicidal spectrum and long application period. It can prevent and control annual weeds, such as crabgrass, quinoa, bluegrass, and mei Niang. It is suitable for tomatoes, potatoes, seedling leeks, sweet (spicy) peppers, eggplants, and broad beans Weeding in some vegetable fields such as , peas, onions, etc., can be used regardless of pre-emergence or post-emergence. Compounded with other herbicides, it has a synergistic effect and is one of the more ideal dry field herbicides. [0003] At present, there are hundreds of patents on the synthesis of isoproturon and its compounding that have been reported at home and abroad. Among them, the invention patents for the synthesis of the ori...

AI Technical Summary

Problems solved by technology

[0004] ① Use hydrogen chloride to form a salt and then react with phosgene to protect the amine group, which can ensure the conversion of cymene, but consume more hydrogen chloride gas and increase the treatment cost of tail gas

[0005] ②During the cold photochemical process of dropping p-cumylaniline toluene solution, because it is added dropwise on the liquid surface, side reactions will occur in part of the dropped p-cymeniline due to insufficient contact with phosgene. In order to ensure better reaction The efficiency of the reaction requires that the concentration of the reactant and the reaction temperature can only fluctuate within a narrow range.

[0006] ③ After the photochemical reaction is completed, phosgene and hydrogen chloride cannot be completely removed when nitrogen is used, resulting in high consumption of dimethylamine during the synthesis of isoproturon, low efficiency of the overall system, and high ammonia nitrogen in the wastewater, which is difficult to dispose of

[0007] ④The whole reaction process is a batch reaction mode, which is not conducive to automatic control operation and high labor cost

The production process has not been reported