文献类型：专利

英文题名：Reduction of particle size of azodicarbonamide foaming agent by reacting hydrazine hydrate and urea to obtain biurea, washing, circularly filtering, adding biurea in dimethyl sulfoxide or N,N-dimethyl formamide, and dripping sodium chlorate

作者：GE Q;WU F;ZHAO M;XIONG Y;NIU D;DENG D;SHUI S

机构：[1]UNIV EAST CHINA SCI&TECHNOLOGY

申请号：CN101838224-A

申请日：2009-03-19

公开日：2010-09-22

语种：英文

收录：DERWENT

摘要：NOVELTY - Particle size of azodicarbonamide (AC) foaming agent is reduced by reacting hydrazine hydrate and urea in solvent A and in presence of catalyst A for 5-20 hours at 100-110 degrees C to obtain biurea; washing biurea with water for 2-3 times to eliminate ammonium hydroxide, and drying; measuring urea content in obtained filtrate, and circularly using filtrate to synthesize biurea; adding the prepared biurea in a solvent B, then adding a catalyst B and stirring, dripping sodium chlorate at 30-60 degrees C, and reacting for 1-10 hours; slowly reducing temperature at rate of 10-20 degrees C/minute; and vacuumizing. USE - Method of reducing particle size of azodicarbonamide (AC) foaming agent (claimed). ADVANTAGE - The method utilizes small device corrosion, has less wastewater discharge, is environment-friendly, and produces AC foaming agent having fine and average particle size. DETAILED DESCRIPTION - Reduction of particle size of AC foaming agent comprises: (A) adding hydrazine hydrate and urea at mole ratio of 1-2:1-10; then adding solvent A (60 mass% of hydrazine hydrate) selected from water, methanol, ethanol or acetonitrile solution with concentration of more than 95%, then adding a reaction catalyst A (0.1-1 mass% of hydrazine hydrate) selected from benzoic acid, oxalic acid, perfluoro caprylic acid, tartaric acid, malic acid, perfluorosulfonic acid ion exchange resin, or perfluorosulfonic acid ion exchange film, and reacting for 5-20 hours at 100-110 degrees C to obtain biurea; (B) washing biurea using water for 2-3 times to eliminate ammonium hydroxide, and drying; (C) measuring urea content in the obtained filtrate based on the national standard GB/T696-94, putting the filtrate to the next reaction for synthesizing biurea, adding needed urea based on amount of hydrazine hydrate so that the ratio of urea and hydrazine hydrate is 3:1-6:1, then adding reaction catalyst A (0.1-1 mass% of hydrazine hydrate), and performing circular reaction for more than 10 times to prepare biurea; (D) adding the prepared biurea in a solvent B (mass ratio of 1:1) selected from water, dimethyl sulfoxide or N,N-dimethyl formamide solution with concentration of 95%, then adding a catalyst B (0.1-1 mass% of biurea) selected from sodium bromide, potassium bromide, iron bromide, or iron chloride and stirring, dripping sodium chlorate at 30-60 degrees C at mole ratio of sodium chlorate to biurea of 1:3-2:3, and reacting for 1-10 hours; (E) slowly reducing the temperature at rate of 10-20 degrees C/minute; and (F) vacuumizing when the temperature is reduced to 0 degrees C.