Technique for co-production of dimethyl carbonate and oxamide

Abstract

The invention discloses a technique for co-production of dimethyl carbonate and oxamide. According to the method, urea and dimethyl oxalate are taken as raw materials, and two products of the dimethyl carbonate and oxamide are obtained by simultaneous synthesis through ester-ammonia exchange reaction under the action of a catalyst. According to the method, amino in the urea and methoxyl in the dimethyl oxalate can be efficiently recombined, so that losses of two groups in forms of ammonia gas and methanol are avoided; the problems of low raw material utilization rate and poor atom economy in a raw material conversion path in the original process of synthesizing the dimethyl carbonate through urea alcoholysis and the original process of synthesizing the oxamide through dimethyl oxalate ammonolysis are mainly solved; and meanwhile, the adverse effects of by-products of the ammonia gas generated in the urea alcoholysis process and the methanol generated in the dimethyl oxalate ammonolysis process on reaction balance are effectively eliminated.

Description

technical field [0001] The invention belongs to the technical field of organic catalytic synthesis, and relates to a process method for co-producing dimethyl carbonate and oxamide by utilizing the amino group of urea and the methoxy group of dimethyl oxalate to efficiently recombine. Background technique [0002] As an important emerging organic chemical intermediate, dimethyl carbonate has attracted the attention of many researchers in the fields of medicine, biology and energy due to its green and environmental protection characteristics. Dimethyl carbonate is mainly used to synthesize polycarbonate and other bulk chemical raw materials; it can replace highly toxic phosgene to participate in the methylation and carbonylation process of organic synthesis; as an additive, it can improve the antiknock performance of gasoline. The initial production method of dimethyl carbonate is phosgene method, but the toxicity and corrosiveness of phosgene limit the application of this met...

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Problems solved by technology

This is because the generation of a large amount of methanol not only dilutes the raw material, reduces the reaction rate, but also reduces the reaction equilibrium constant, making it difficult to move the equilibrium to the product direction.

In addition, a large number of effective methoxy groups can only generate methanol with low added value after being replaced by amino groups, and the atom economy of the reaction is poor; the amino groups are derived from ammonia molecules in the gas phase, which makes the reaction only possible in gas-liquid Two-phase interface, the utilization rate of ammonia gas is very low, and the ammonia gas that is too late to react cannot be discharged directly, and a special ammonia corrosion-resistant device is required for recycling, which leads to an increase in equipment and process costs

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