| 1 Objectives:Cinnamic acid organisms are an important pharmaceutical intermediate,which is widely used in drug synthesis and development.In order to improve the purity of the product,crystallization is often used as an important method in solids separation and purification.The solubility of solids is the basis of dissolution and crystallization process,However,the experimental data and theoretical research about this kind of material are insufficient.This paper focused on cinnamic acid and its other two solid derivatives,including p-coumaric Acid and caffeic acid,obtained solubility data and thermodynamic parameters,which can provide model and data basis in its industrial refining.Besides,different concentrations of ethanol + water solutions are often used in the industrial production of cinnamic acid.In order to effectively recover the ethanol from the waste liquid,reduce the pollution and discharge of organic reagent in wastewater.This study focus on simulation and recover the different concentration of ethanol solution.2 Methods:(1)This study takes the cinnamic acid,p-coumaric acid and caffeic acid as the research objects and measured the solubility of the three cinnamic acid organisms.(2)The solutes before and after dissolution are same,confirming that the solute structure do not change due to the results of X ray diffraction.The melting point and melting enthalpy is measured by differential scanning calorimeter.(3)Choose the commonly used thermodynamic model correlate the solubility data of three substance in different solvents.(4)The article simulate the separation of 100 kg/h ethanol solution by the chemical process software Aspen Plus.Using orthogonal design optimization the best operating process.3 Results:(1)Measured the solubility of cinnamic acid in nine mono solvents,including methanol,ethanol,1-propanol,2-propanol,n-butanol,isobutanol,methyl acetate,ethyl acetate and water,and also in the ethanol + water mixtures from(293.15 to 328.15)K,measured the solubility of p-coumaric acid acid in ten mono solvents,including methanol,ethanol,1-propanol,2-propanol,n-butanol,isobutanol,acetone,methyl acetate,ethyl acetate and water and also in the ethanol + water mixtures from(293.15 to 333.15)K,measured the solubility of caffeic acid in nine mono solvents,including methanol,ethanol,1-propanol,2-propanol,n-butanol,isobutanol,acetone,ethyl acetate and water and also in the ethanol + water mixtures from(293.15 to 333.15)K by gravimetric method.Draw the solubility curve of solutes in pure and mixture solvents and eutectic renderings,analysis and discuss the variation of solubility.The solubility of the three substances increases with the increase of temperature,And in the same solvent,the solubility of the three substances is in the order of cinnamic acid>p-coumaric acid>caffeic acid.(2)Enthalpy(?dHm),dissolving entropy(?dSm)obtained of the three substance and it's all positive.The results illustrate that the dissolution of the three substances is an irreversible and endothermic process.(3)The solubility of cinnamic acid,p-coumaric acid and caffeic acid in pure solvents were correlated using Apelblat model,Van't Hoff model,?h model,NRTL model,Uniquac model,and Wilson model,and calculated the relevant thermodynamic parameter.The average relative deviations between model correlation value and actual measured value of cinnamic acid are 0.82%,1.42%,0.88%,1.26%,1.11%and 0.80%,respectively.Van't Hoff model is the best-fitting.The average relative deviations between model correlation value and actual measured value of p-coumaric acid are 0.49%,0.60%,0.61%,1.33%,0.68%and 1.11%,respectively.The Apelblat model equation have the best fitting results;The average relative deviations of caffeic acid are 0.68%,0.73%,0.92%,1.33%,1.92%and 2.68%,respectively.And the Apelblat model equation has the best fitting results.The solubility of the three cinnamic acid substances in mixed solvents were correlated Apelblat model,Van't Hoff model,NRTL model,Wilson model,Uniquac model,JA7 model and ?h model.The average relative deviations between model correlation value and actual measured value of cinnamic acid are 0.69%,0.81%,2.64%,2.76%,2.88%,1.56%and 1.29%,respectively,the Apelblat model equation have the best fitting results.The average relative deviations of p-coumaric acid are 0.26%,0.15%,2.46%,2.90%,2.80%,0.82%and 0.19%,respectively,the Apelblat model equation have the best fitting results.The average relative deviations between model correlation value and actual measured value of caffeic acid 0.73%,0.73%,4.82%,2.01%,3.23%,0.77%and 0.52%,respectively,the Apelblat and Van't Hoff model have the good fitting results.(4)This experiment adopts the Aspen Plus chemical process software simulated and recycled the waste liquid in the crystallization process of cinnamic acid organisms.The waste liquid is different concentrations of ethanol + water solution.Finally,the best parameters of the distillation obtained.4 Conclusion(1)This study focus on cinnamic acid,p-coumaric acid and caffeic acid,Measured the solubility of the three substance in different solvents.The trend of the three cinnamic acid organisms in different solvents is the solubility increases gradually with the increase of temperature.The solubility sequence of the solute in the pure polarity solvent is cinnamic acid>p-coumaric acid>caffeic acid.In ethanol + water mixed solvent,the solubility increases with the increase of alcohol content in the mixture.(2)The solubility of the three substance in pure solvents were correlated by Apelblat model,Van't Hoff model,?h model,NRTL model,Uniquac model,and Wilson model,and the solubility in mixed solvents were correlated by Apelblat model,Van't Hoff model,NRTL model,Wilson model,Uniquac model,JA7 model and ?h model.Each of the models has the good-fitting.(3)NRTL model could accurately describe most distillation process of ethanol-water system;Optimizating the best theoretical plate number,feed location,reflux ratio and distillation recovery operation parameters through orthogonal design. |
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