Synthesizing technology and device for improving nicosulfuron purity

Abstract

The invention relates to a synthesizing technology and device for improving nicosulfuron purity. The technology is characterized in that 3-[(N,N-dimethylaminocarbonyl)-2-pyridyl] sulfonylcarbamate, 4,6-dimethoxy-2-pyrilamine and methylbenzene are heated to condense; mixed steam of methylbenzene treated as a solvent in the reaction and ethyl alcohol produced in the condensation enters a condenser;the mixed solution of condensed methylbenzene and ethyl alcohol enters an absorbent storing tank; methylbenzene absorbed through the ethyl alcohol is heated through an absorbent, and then the methylbenzene is added to a reaction kettle; the reaction is stopped when the content of the ethyl alcohol in the mixed steam produced by the reaction kettle is less than 0.0005%; the mixed solution in the reaction is cooled and centrifuged to obtain nicosulfuron. According to the technology, the ethyl alcohol produced in the reaction can be quickly and effectively removed, and the reaction is promoted to forwards perform, thus the purity and the yield of nicosulfuron can be improved; and moreover, the methylbenzene treated as the solvent and taken out through the ethyl alcohol is recycled, so that more energy is saved; and the reaction cycle is greatly reduced through the design, and as a result, the production efficiency is improved.

Description

technical field [0001] The invention relates to the technical field of pesticide compound synthesis, in particular to a synthesis process and device for improving the purity of nicosulfuron. Background technique [0002] The chemical formula of nicosulfuron is 2-(4,6-dimethylpyrimidin-2-pyrimidinylcarbamatesulfonyl)-N,N-dimethylnicotinamide, which is a new generation of broad Spectrum, high efficiency, low concentration, low residue and high selectivity herbicide. At present, the route to synthesize nicosulfuron is mainly 3-[(N,N-dimethylcarbamoyl)-2-pyridyl]sulfonylcarbamate (referred to as urethane) and 4,6 dimethoxy Base-2-pyrimidinamine (referred to as pyrimidineamine) is condensed to remove a molecule of ethanol. In this method, rectification is used to separate ethanol, but the rectification time is generally between 20-40 hours and the reaction time is longer. The ethanol extracted from the top contains part of the toluene solvent, so it is necessary to add an equal...

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Problems solved by technology

At present, the route to synthesize nicosulfuron is mainly 3-[(N,N-dimethylcarbamoyl)-2-pyridyl]sulfonylcarbamate (referred to as urethane) and 4,6 dimethoxy Base-2-pyrimidinamine (referred to as pyrimidineamine) is condensed to remove a molecule of ethanol. In this method, rectification is used to separate ethanol, but the rectification time is generally between 20-40 hours and the reaction time is longer. The ethanol extracted from the top contains part of the toluene solvent, so it is necessary to add an equal amount of fresh toluene solvent to the reaction kettle. Due to the addition of fresh solvent to the kettle, the temperature in the kettle will drop or the temperature will fluctuate, which will reduce the rectification capacity. The separation effect of the tower, so the reaction time of this method is long, the energy consumption is large, and the yield (about 95%) and content (about 95%) are not high

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