Novel method for preparing dihydroxyurea

Abstract

The invention relates to a novel method for preparing dihydroxyurea and belongs to the field of organic synthesis. The dihydroxyurea belongs to a novel salt-free reducing agent which is used for spent fuel post treatment and has good application prospects. The novel method is mainly characterized in that under the anhydrous conditions, solid phosgene and hydroxylamine are used for synthesizing the dihydroxyurea. Concretely, hydroxylamine and potassium acetate are firstly placed into a three-opening flask, are placed into an ice salt bath and are stirred into emulsion. In addition, the solid phosgene is dissolved into 1, 4-dioxane, the mixed liquid is placed into a constant-pressure liquid dripping funnel, when the temperature is below 0 DEG C, the solid phosgene mixing liquid is dripped into the emulsion at the controlled speed, and the temperature is maintained at 0 to 5 DEG C. The reaction is continuously carried out for 2 hours after the dripping completion, and then, the pH of the solution is regulated to 2 to 3 through concentrated hydrochloric acid. Solid materials are removed through filtering, solvents are removed through rotary evaporation on filter liquid, and solid is obtained. A proper amount of tetrahydrofuran is used for extracting the dihydroxyurea in the solid, the solvents are removed through the rotary evaporation, coarse dihydroxyurea is obtained, ethanol is used for recrystallization, and the pure dihydroxyurea is obtained. Through the detection and characterization on products by various methods, the product purity is 95 percent, and the yield is 57 percent.

Description

technical field [0001] The invention relates to a new method for preparing dihydroxyurea, which belongs to the field of organic synthesis. Background technique [0002] The rapid development of nuclear energy will inevitably produce a large amount of used nuclear fuel, that is, spent fuel. Dihydroxyurea is a new salt-free reducing agent for spent fuel reprocessing, which can effectively separate Pu and Np from U; theoretical predictions and preliminary experimental results show that the main product of dihydroxyurea decomposition is gas, which is beneficial to waste disposal. The least quantified, so it is a promising new salt-free reducing agent. But, there is no manufacturer to produce both at home and abroad. [0003] The existing method for synthesizing dihydroxyurea is as follows: solid phosgene reacts with hydroxylamine hydrochloride, the acid-binding agent is potassium acetate, and the solvent is water and dioxane. The purpose of adding water is in order to increas...

AI Technical Summary

Problems solved by technology

Although potassium acetate is added, because the system contains a large amount of dioxane and a small amount of water, potassium acetate and hydroxylamine hydrochloride cannot be completely dissolved, and potassium acetate cannot completely free the hydroxylamine in hydroxylamine hydrochloride

The above two points may be the reason for the low yield of dihydroxyurea, and also the reason why there are still more hydroxylamine hydrochloride after the reaction

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