| 2-Nitrophenylacetonitrile and 4-nitrophenylacetonitrile are important intermediates in organic synthesis areas.They are widely used in chemical,pharmaceutical,liquid crystal,agricultural and other industries and play a significant role in chemical production and drug synthesis.It is well-known that nitrophenylacetonitrile is also an essential intermediate for the syntheses of aktaril,salidroside,mirabelone,antihypertensive atenolol and antidepressant venlafaxine,etc.contributing to a great demand in domestic and foreign markets.Nowadays,2-nitrophenylacetonitrile and 4-nitrophenylacetonitrile are mostly produced by nitration of phenylacetonitrile in industry but for the low selectivity.While most of 4-nitrophenylacetonitrile is obtained,a small amount of 2-nitrophenylacetonitrile is produced by-product.In addition,the nitrophenylacetonitrile isomers are difficult to separate by means of distillation operation due to their similar physicochemical properties,especially the boiling point.Solvents crystallization combined with the lower temperature of nitrification can effectively separate them.Solvent crystallization as an economy,low-energy and environment-friendly separation method can effectively compelete the unsolvable problems of distillation,extraction and adsorption and obtain green safe separation.In this dissertation,the binary and ternary solid-liquid equilibrium of different systems was studied.The results provide the basis for the separation processes of nitrophenylacetonitrile isomersThe equilibrium solubilities of 2-nitrophenylacetonitrile and 4-nitrophenylacetonitrile in methanol,ethanol,n-propanol,isopropanol,acetonitrile,acetone,toluene,ethyl acetate,n-butanol,2-butanone,isobutanol,cyclohexane,acetic acid,water,1,4-dioxane and ethylbenzene were measured by using isothermal dissolution method.The solubility of nitrophenylacetonitrile isomers increased with a rise of temperature,and obeyed the sequence from high to low in different solvents for 2-nitrophenylacetonitrile at the certain temperature:?ethyl acetate,1,4-dioxane,acetone>2-butanone>acetonitrile>toluene?>?acetic acid,ethylbenzene?>methanol>ethanol>n-propanol>isopropanol>n-butanol>isobutanol>cyclohexane>water and the mole faction solubility of 4-nitrophenylacetonitrile ranked as 1,4-dioxane,ethyl acetate>acetone>?acetonitrile,2-butanone?>toluene>acetic acid>ethylbenzene>methanol>ethanol>n-propanol>n-butanol>isopropanol>isobutanol>cyclohexane>water.Moreover,the obtained solubility values were correlated by the modified Apelblat model,?h model,NRTL model and Wilson model.The maximum values of relative average deviation?RAD?and root-mean-square deviation?RMSD?acquired with the four models were no more than 4.97%and 4.97×10-3,respectively,and the modified Apelblat model provided better results than the other three models.In addition,the solute-solvent and solvent-solvent interactions was studied based on the KAT-LSER equation.Meanwhile,the mixing properties of 2-nitrophenylacetonitrile and 4-nitrophenylacetonitrile in pure solvents were calculated.The equilibrium solubilities of nitrophenylacetonitrile isomers in?ethyl acetate+methanol?,?ethyl acetate+ethanol?,?ethyl acetate+ n-propanol?and?ethyl acetate+isopropanol?solvent mixtures were measured by using isothermal dissolution method.The solubility of 2-nitrophenylacetonitrile and 4-nitrophenylacetonitrile increased with increasing temperature and mass fraction of ethyl acetate for the binary systems studied and no solubilization phenomenon was found during entire experiments.Moreover,the Jouyban-Acree model,Van't Hoff-Jouyban-Acree model,Apelblat-Jouyban-Acree model,Sun model and Ma model were used to correlate the solubility data that obtained the corresponding model parameters.The RAD and RMSD were no more than 6.34%and 6.44×10-3,respectively,and the Jouyban-Acree model achieved best correlation results.In the meanwhile,the standard enthalpy of dissolution and transfer properties of 2-nitrophenylacetonitrile and 4-nitrophenylacetonitrile in mixed solvents were calculated.The solid-liquid phase equilibria of 2-nitrophenylacetonitrile+4-nitrophenylacetonitrile+ethanol and 2-nitrophenylacetonitrile+4-nitrophenylacetonitrile+toluene at 303.15 K,313.15 K and 323.15 K were measured by Schreinemaker's method,and the ternary phase diagrams were obtained.The co-crystallization regions were constantly decreased with increasing temperature.The crystallization region of 4-nitrophenylacetonitrile was lager than that of 2-nitrophenylacetonitrile at a given temperature,especially in 2-nitrophenylacetonitrile+4-nitrophenylacetonitrile+toluene system,and toluene was more faviourable in separation of nitrophenylacetonitrile isomers.In addition,the solubility data was correlated with the NRTL model and Wilson model.The RMSD were 5.02×10-3 and 8.45×10-3 respectively,which illustrated that the NRTL model colud be corral ate the 2-nitrophenylacetonitrile+4-nitrophenylacetonitrile+ethanol/toluene ternary systems accrurately. |
PDF Full Text Request