A method for the continuous solvent-free reaction synthesis of hexazinone

Abstract

The invention discloses a method for synthesizing hexazinone through continuous solvent-free reaction, which comprises preparation of cyclic ester compound, synthesis of hexazinone and purification of hexazinone. This application uses N-ethylcarbonyl-N,N',N'-trimethylguanidine and cyclohexyl isocyanate in a certain ratio (molar ratio 1:1) after the static mixer A reacts at room temperature, and the mixed solution passes through static Mixer B generates hexazinone under the action of catalyst sodium methoxide. After the generated hexazinone is pickled and neutralized by the static mixer, the organic phase enters the melting crystallizer and crystallizes. After passing the test, it can be sliced ​​to obtain a content greater than 99%. , the yield of hexazinone is about 95%. This application does not need to add n-hexane and toluene solvents, and there is no need to consider the problem of solvent volatilization in the process of neutralization, washing, distillation and drying of hexazinone, which can save production cost, and there is no need to consider the problem that a part of hexazinone is also taken away in the mother liquor during solvent crystallization, thereby improving the effect of yield.

Description

technical field [0001] The invention relates to the technical field of preparation of hexazinone, in particular to a method for synthesizing hexazinone through continuous solvent-free reaction. Background technique [0002] Hexazinone is a herbicide that kills herbicides, and its mechanism of action is to inhibit the photosynthesis of the plants to be controlled, and inhibit the absorption of the roots and leaves of the plants to be controlled, so as to achieve the control effect. [0003] Regarding its synthesis method, there are mainly three kinds of cyanide amine method, S-methylisothiourea method and methyl isothiocyanate method, among which the important synthetic route is through N-ethylcarbonyl-N,N ',N'-Trimethylguanidine and cyclohexyl isocyanate are reacted in a tubular mixing reactor, and then mixed with sodium methoxide in a tubular reactor to form hexazinone. The reaction is as follows: [0004] [0005] In the patent CN201310729322.5, the synthesized N-ethox...

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Problems solved by technology

[0007] In the above two patents, solvents such as toluene and n-hexane are used in the synthesis and crystallization, and the use of solvents will cause the loss of solvents in the processes of neutralization of hexazinone and water washing, distillation and drying, and in the process of distillation and drying When, also can increase energy consumption, also take away part of hexazinone product in the mother liquor of the mixed solvent crystallization of normal hexane and toluene simultaneously, can cause yield and reduce, thereby increased the cost of synthetic hexazinone, toluene and n-hexane The use of alkane will also cause certain damage to the environment and the human body, so it is particularly important to invent a method for the continuous solvent-free reaction synthesis of hexazinone

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