Study on Differential Rate Kinetics Analysis Based on the Substitution Reaction of Rare Earth-PHA with CyDTA

The kinetic behaviours of the substitution reaction of rare earth-PHA with CyDTA were studied systemati-cally.The relationship between the rate constant and atomic number was discussed.The rate differentiation val-ue Rd(Rd=lgkz+n-lgkz)was proposed to evaluate the possibility of differential kinetic analysis.The Rd valuebetween the neighbouring lanthanide ions first increases and then decreases along with increasing atomic number,so that the middle and heavy rare earth mixture（such as Sm-Gd and Gd-Y）are ideal systems for thedifferential rate kinetic analysis.