Study On Crystallization Process Of Bis (2,4,6-trimethylbenzoyl) Phenylphosphine Oxide

Bis(2,4,6-trimethylbenzoyl)(XBPO)is an ultraviolet initiator.The XBPO crystal products obtained by evaporation crystallization have many problems such as small particle size,wide particle size distribution,poor flowability and seriously agglomeratio,which have a bad impact on the product quality.In this paper,XBPO was studied systematically from crystal thermodynamics to crystal morphology and crystallization process by computer software simulation and experimental.The solubility of XBPO in eight solvents was measured and fitted by NRTL,λh and Apelblat empirical equation to obtain the crystal thermodynamic data of XBPO.The surface entropy factor of XBPO crystal is estimated.The structure of XBPO single crystal was analyzed and four kinds of intermolecular interactions in XBPO crystal were determined.MS software was used to predict the crystal habits of XBPO in vacuum and in real growth environment,which was consistent with the experimental results.The main crystal facets of XBPO crystals were determined,and the reasons for the solvents influence on the crystal habits were explained by analyzing the diffusion and adsorption of solvents on the crystal facets.The growth rate of {020} facet in a range of supersaturation was measured,and obtained the relationship between growth rate and supersaturation by fitting empirical relationship.The reasons for the variation of crystal habits with supersaturation were analyzed.The evaporation and cooling crystallization process of XBPO were studied.By studying the evaporation crystallization conditions: temperature,vacuum degree,stirring rate,add quantity and the seed crystal time,we invested the influence of particle size,particle size distribution and yield.And looking at the influence of four different cooling processes of crystal habits and liquidity.Finally,the optimal conditions improved XBPO product granularity,crystal habits and liquidity.