Research On The Crystallization Process Of Benzophenone

Benzophenone is one kind of photo initiators.Benzophenone and its derivatives are widely used in many areas,such as sunscreen cosmetics,perfume,pharmaceutical industry,UV absorbers and photosensitizers.In the traditional industry,rectification operation is often used to achieve the purification and separation of benzophenone.However,the rectification operation cannot always obtain product with high purity and require large energy consumption.Crystallization has the advantage of low energy consumption and high product purity,the purification of benzophenone by crystallization technology has gradually attracted the attention of researchers.In this context,with the purpose of developing new crystallization process,the thermodynamic properties of benzophenone,crystal morphology and crystallization process of benzophenone were studied.First of all,the thermodynamic properties of the benzophenone were studied.The solubility of benzophenone in binary system(methanol + acetonitrile,methanol +acetone,methanol + ethyl acetate)was experimentally determined by static method.Apelblat simplified empirical equation,λh equation and NRTL mixing model were used to correlate the experimental solubility data,respectively.At the same time,the NRTL model and solubility data were used to calculate the mixing and dissolution thermodynamic properties.Secondly,the BFDH and AE models were used to predict the benzophenone crystal habit under vacuum condition.It was found that there was a big difference between the predicted crystal habit and the actual habit which was greatly affected by the solvent.The Materials Studio was used to calculate the adhesion energy of different crystal faces under the influence of S + water and the crystal habit was corrected.The predicted crystal habit closer to the actual product was obtained.Finally,based on the above theoretical research,the crystallization process of benzophenone was designed and optimized by investigating the effects of crystallization methods,solvent system,cooling end temperature,adding rate of antisolvent,stirring rate on crystal habit,particle size distribution,product purity and yield of benzophenone product.The product has high purity,complete crystal habit,uniform particle size distribution,good fluidity,high process yield and meets the requirements of relevant cooperative enterprises.Through literature review,no similar reports on above researches have been reported in domestic and foreign literature.