Study On The Dilution Crystallization Process And Crystallization Technology Of LLM-105

2,6-diamino-3,5-dinitropyrazine-1-oxide?LLM-105?is a new type of heat-resistant explosive with high energy and low sensitivity,and has excellent comprehensive performance,and has attracted much attention in the field of energetic materials.The crystallization process of LLM-105 was studied in this paper.The crystallization thermodynamic and kinetic parameters of LLM-105 were obtained,and the crystallization technology was optimized.The main research contents are as fllows:?1?The crystal morphology prediction of LLM-105 in vacuum was simulated by Materials Studio7.0.The molecular interface models of LLM-105 with solvents of dimethyl sulfoxide,N,N-dimethylformamide,N-methylpyrrolidone and dimethyl sulfoxide-water were established.The interaction energy between solvent and crystal plane was calculated,and the crystal morphology of LLM-105 in different solvents was predicted by MAE model.The results showed that the crystal morphology of LLM-105 in dimethyl sulfoxide solvent was more regular,and with a smaller aspect ration and closer proportion of each plane,and the crystal morphology of DMSO/H₂O mixed solvent is different under different mass ratios.?2?The solubility of LLM-105 in DMSO and DMF solvent was measured by laser dynamic method.The solubility data was correlated using the Apelblat equation,the van't Hoff equation and the empirical equation.The equation parameters were determined.The dissolution enthalpy,dissolution entropy and dissolution Gibbs energy of LLM-105 in DMSO and DMF solvent were calculated based on the solubility data.The results showed that the solubility of LLM-105 in both solvents increases with increasing temperature,and the dissolution process is endothermic and non-spontaneous.?3?The crystallization kinetics of LLM-105 in DMSO and DMF solvent were studied by batch dynamic method.The data of suspension density,supersaturation,stirring intensity,crystal nucleation rate and growth rate during crystallization process were determined.The crystallization kinetics model was established by least squares regression.The crystal growth of LLM-105 in DMSO and DMF solvent is independent of particle size.During the crystallization of LLM-105 in DMSO solvent,temperature and agitation accelerate the nucleation rate and slow down the growth rate.Based on the kinetic model,the influence of kinetic parameters on the crystallization process of LLM-105 was analyzed.?4?The crystallization technology of LLM-105 in DMSO-H₂O system was determined according to the results of crystal morphology prediction and crystallization kinetics.The particle size and morphology was used as indicators,and the crystal products were analyzed by XRD and DSC.The effects of different crystallization conditions on the crystal quality of LLM-105 were investigated.The optimal crystallization technology conditions are:the temperature is 50°C;the dropping rate is 1.53 mL·min^-1;the stirring rate is 300 r·min^-1;the initial concentration is 3.92 g·100mL^-1.The crystal particles have regular morphology,uniform distribution and good dispersibility.The average particle size M.S is 6.06?m,and the C.V value is 3.05.