SOLVENT EFFECT ON THE RATE CONSTANT OF ROTETIONAL ISOMERISM IN SOLUTIONS

点击翻译按钮获取中文摘要

THE PURPOSE OF THIS WORK IS TO ELUCIDATE THE RATE CONSTANT OF ROTATIONAL ISOMERISM IN SOLUTIONS BY ULTRASONIC AND RAMAN SPECTROSCOPIC METHODS.THE ULTRASONIC RELAXATION SPECTRA OF SEC-BUTYLBROMID IN N-HEXANE AND DIISOBUTYLPHTHALATE WERE MEASURED IN THE FREQUENCY RANGE FROM 5 MHZ TO 800MHZ.THE VISCOSITY DEPENDENCE OF THE RELAXATION FREQUENCY OF THE RATE CONSTANT WERE OBSERVED.THE CHANGES IN THE ENTHALPY (DELTAH) AND VOLUME (DELTAV) ACCOMPANYING THE ROTATIONAL ISOMERISM WERE ESTIMATED FROM THE TEMPERATURE AND PRESSURE DEPENDENCE OF THE RAMAN SPECTRA CORRESPONDING THE ROTATIONAL ISOMERS.THE VALUES OF DELTAH AND DELTA1V DECREASED WITH INCREASING THE VISCOSITY IN SOLUTIONS.ON THE OTHER HANDS,THE ACTIVATION ENTHALPY,WHICH IS ESTIMATED FROM THE TEMPERATURE DEPENDENCE OF THE ULTRASONIC FREQUENCY ARE AROUND 18 KJ/MOL.THE VISCOSITY DEPENDENCE OF THE RATE CONSTANT OF SEC-BUTYLBROMID IS NOT INTERPRETED IN TERMS OF THE KRAMERS THEORY.THE DEVIATION FROM THE THEORY WAS RECOGNIZED IN THE HIGH VISCOSITY REGION.THE RESULTS OBTAINED FROM THE ULTRASONIC AND RAMAN SPECTROSCOPY INDICATED THAT THE POTENTIAL CURVES OF THE ROTATIONAL ISOMERISM IS MODIFIED BY THE CHANGE IN THE VISCOSITY IN SOLUTION.THAT IS THE INTERACTION BETWEEN SOLUTE AND SOLVENTS.IT IS DESIRABLE TO DEVELOP THE NEW THEORY OF THE RATE CONSTANT,WHICH PREDICTS THE VISCOSITY DEPENDENCE.