System and method for synthesizing hexazinone by continuous pipeline reactions

Abstract

The invention discloses a system and method for synthesizing hexazinone by continuous pipeline reactions, and relates to the hexazinone synthetic method field. The system includes a first solution tank, a first material transferring pump, a filter, a shell-and-tube heat exchanger, a pipeline reactor, a second solution tank, a second material transferring pump, an evaporator, a neutralization washing kettle, a third material transferring pump, a condenser, and a removed solvent receiving tank; the first solution tank is connected to the first material transferring pump through a pipeline; the first material transferring pump is connected to the filter through a pipeline; the filter is connected to the shell-and-tube heat exchanger through a pipeline; the shell-and-tube heat exchanger is connected to the pipeline reactor through a pipeline; the second solution tank is connected to the second material transferring pump through a pipeline; the second material transferring pump is connectedto the pipeline reactor through a pipeline; the pipeline reactor is connected to the evaporator through a pipeline; the evaporator is connected to the neutralization washing kettle through a pipeline; the third material transferring pump is connected to the neutralization washing kettle through a pipeline; the condenser is connected to the evaporator through a pipeline; and the removed solvent receiving tank is connected to the condenser through a pipeline.

Description

technical field [0001] The invention relates to a system and method for synthesizing hexazinone, in particular to a system and method for synthesizing hexazinone through continuous pipeline reaction. Background technique [0002] Hexazinone is a high-efficiency, low-toxicity, broad-spectrum and high-selectivity forestry herbicide widely used in the world at present. It is used for seedling tending in evergreen coniferous forests such as Korean pine, masson pine, and spruce, weeding and irrigation before afforestation, In the existing synthesis technology of hexazinone [application (patent) number: CN201310729322.5)] for forest fire prevention and forest land improvement, etc.: toluene, the produced N-ethoxycarbonyl-N,N',N' -Trimethylguanidine and 1 part by weight of cyclohexyl isocyanate are put into the cyclization kettle to keep warm, heat up to 45°C-50°C for 2 hours after 1 hour, then heat up to 70°C-75°C for 3 hours; then cool to 35°C -40°C, feed dimethylamine gas into ...

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Problems solved by technology

[0004] However, because the cyclization reaction of cyclic esters under the catalysis of sodium methoxide is an exothermic reaction, the reaction speed is very fast; even if the methanol solution of sodium methoxide is added dropwise in the kettle reaction, the reaction speed is also difficult to control, and it is very easy to be caused by reaction. The risk of spillage or explosion is very severe, and the safety risk is very high. In addition, as a tank reaction, the ethanol generated by the reaction, the methanol brought in by the catalyst and a small amount of water in the system are not removed in time. Both will further react with the product hexazinone, and replace the N, N'-dimethyl groups on the hexazinone molecule to become ethoxy, methoxy, and hydroxyl, and generate some impurities with molecular weights of 253, 239, and 225

Thereby make the impurity that this step reaction generates more, yield is lower, and step is loaded down with trivial details, has reduced synthesis efficiency

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