Study On Crystallization Process Of Spirotetramat

Spirotetramat is a new type of insecticide and acaricide of quaternary acid derivatives with good endosmosis,which can be conducted upward through the xylem and phloem of plants and has a wide insecticidal spectrum with long validity,and can control mites,moths and other pests on many crops.The research on spirotetramat at home and abroad is mainly focused on the industrial synthesis route,and the crystallization process is less reported in the literature.In this paper,the crystallization process of spirotetramat was systematically investigated.The solubility data of spirotetramat in four binary solvent mixtures of methanol +water,ethanol + water,isopropanol + water and acetone + water at 278.15-323.15 K were determined by dynamic laser method,and the super-solubility data were also determined under several solvent compositions.The Apelblat model,λh model,Van’t Hoff model,Jouyban-Acree model and NRTL model were applied to fit the solubility data.Subsequently,the KAT-LSER model was applied to analyze the effect of solute-solvent intermolecular interactions on solubility.Finally,the mixing thermodynamic properties of spirotetramat in the above four binary mixed solvent systems were calculated based on the Van’t Hoff equation,which provided basic data and theoretical support for the study of crystallization kinetics and crystallization process.The variation of the induction period of spirotetramat in different solvents with the supersaturation ratio was measured by laser monitoring method,and the interfacial tension of the solution was obtained by regression analysis,and the primary nucleation parameters were calculated according to the classical homogeneous nucleation theory.The intermittent dynamic method was used to study the crystallization kinetics of spirotetramat,and the particle size distribution of the samples was determined by Mastersizer 3000 particle size meter.And the nucleation and growth rates of crystals under different conditions were calculated by applying the method of moment transformation based on the particle size equation.The influence of each factor on the nucleation process was investigated in conjunction with the kinetic parameters.The solvation and crystallization process of spirotetramat was investigated by systematic experiments.The effects of solvent type,stirring speed,crystalline species addition,solubilizer ratio,solubilizer drop acceleration rate and crystallization time on the quality of spirotetramat were investigated systematically by single-factor experiments to determine the optimal process conditions for solubilization crystallization of spirotetramat.Through the optimized crystallization process,the average particle size of the product reached 318 μm,the diameter distance was reduced to 1.195,the yield reached more than80% and the crystal acquisition was relatively complete.The diffraction data of spirotetramat were resolved using Materials Studio molecular simulation software,and the AE model was used to predict the morphology of spirotetramat crystals in vacuum,and the dominant growth surface of the crystals was obtained.Subsequently,the interaction of ethanol solvent with the crystalline planes of spirotetramat was investigated,and the modified AE model was used to predict the crystal morphology of spirotetramat in ethanol solvent,and the simulated crystal acquisition was closer to the actual crystal acquisition.