STUDY ON PHASE TRANSITION THERMODYNAMICS OF 4-METHYL-COUMARIN DERIVATIVE

This letter deals with the study on thermodynamic characteristics of phase transition for 4-methyl-coumarin derivatives, i. e. 4-methyl-7-aminocoumarin, 4-methyl-7-hydroxycoumarin, 4-methyl-7-dimethylaminocoumarin and 4-methyl-7-diethylaminocoumarin (hereinafter C120,