Novel preparation method of dimethoxy propyl diimine dimethyl bisulfate

Abstract

The invention discloses a novel preparation method of dimethoxy propyl diimine dimethyl bisulfate. Cheap propane diamide is taken as the raw material, then O-methylation of propane diamide can be achieved in the presence of a methylation agent (dimethyl sulfate) under the catalytic conditions of Lewis acid, dimethoxy propyl diimine dimethyl bisulfate can be obtained stably, and the yield is high. Moreover, the production cost is low, the operation is simple, and the method is environment-friendly and equipment-friendly, and is suitable for industrial production. The prepared dimethoxy propyl diimine dimethyl bisulfate can be used to produce 2-amino-4,6-dimethyoxy pyrimidine and 2-chloro-4,6-dimethyoxy pyrimidine, the reaction activity is equivalent to that of dimethoxy propyl diimine dihydrochloride, and moreover, the stability is better.

Description

technical field [0001] The invention relates to the technical field of pesticides, in particular to a new method for preparing dimethoxypropylenediimine dimethyl hydrogensulfate, which belongs to the category of organic chemical synthesis. Background technique [0002] Dimethoxypropanediimide salt is a very important intermediate in organic synthesis, mainly used in the key intermediates of sulfonylurea herbicides, 2-amino-4,6-dimethoxypyrimidine and pyrimidine salicylic acid Synthesis of 2-chloro-4,6-dimethoxypyrimidine, an important intermediate of herbicides. [0003] The usual preparation method of dimethylpropanediimide salt is to use malononitrile as raw material, add twice the amount of methanol, in an organic solvent (such as: toluene, methyl acetate, methanol, dimethylformamide, tetrahydrofuran, three Toluene, methyl isobutyl ketone, dioxane, chloroform, etc.), feed dry hydrogen chloride gas at low temperature, such as U.S. Patents USP4310470, USP4412957, USP449510...

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Problems solved by technology

[0008] 3) The preparation process of anhydrous hydrogen chloride is cumbersome, and there are many post-processing devices. Some equipment must be customized and imported to achieve better results, such as filter elements in demisters, demisters, and acid mist separators. Domestic The blocking effect of the equipment is limited, it is easy to reach saturation and the service life is only 3 months;

[0009] 4) The detection and measurement of anhydrous hydrogen chloride are relatively difficult, and the production is mainly based on experience, which cannot be tracked, and it is easy to cause the target product yield to be unstable, and the reason cannot be found;

[0010] 5) There is a lot of excess hydrogen chloride gas in this process, and the gas that does not participate in the reaction must be disposed of in a way, and the amount of waste gas is large;

[0011] 6) The equipment requirements for the process of preparing anhydrous hydrogen chloride gas are relatively high. It is relatively easy for qualified enterprises to adopt chlorine and hydrogen synthesis. Those without conditions generally use phosphorus trichloride hydrolysis, hydrochloric acid and hydrogen chloride with a large amount of gas generation. Hydrogen chloride with a lot of water has special requirements on materials. Although plastics can be anti-corrosion, they are easy to age, and the welds are not pressure-resistant, and they are easy to leak and cause environmental pollution; steel-lined PO and steel-lined PTFE are custom-made parts, and the cost is high; phenolic resin The connection of FRP is difficult and the cost is not low, and the pressure is also a test for it

The price of malononitrile produced by these two methods is relatively high. In the production of dimethoxymalondiimine disalt, the cost of malononitrile accounts for more than 80%, resulting in an increase in the cost of corresponding downstream products.

[0013] 8) The toxicity of malononitrile is similar to that of cyanide, which is a highly toxic and dangerous chemical; malononitrile is a paste solid at room temperature, packed in an iron drum, and must be heated and melted before feeding. When opening or closing the lid, if the safety protection If the measures are not in place, it is very easy to cause inhalation poisoning

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