Study on the Purification Process of HNS

The purity of HNS-Ⅱ was increased by recrystallization.Orthogonal design method is used to analyze the optimal conditions of experiment technique.The effects of circumfluence reaction temperature,reaction time,solution scale and washing solvent on purity of production were investigated.The results indicate that the reaction temperature is main influence factor and reaction time has some impacts on HNS purity.However,solution scale and washing solvent have a little influence on it.The times of recrystallization was decided by material purity.Finally,the purity of HNS can over 99.7%,while the reaction temperature is(160±2)℃,reaction time is 1.5h,solution scale is 1∶7(g/mL) and washing solvent is100% methanol.