The solid state reactions of Cu(OAc)2.H2O with 1-phenyl-3-methyl-4-benzoylpyrazolone-5(HPMBP, keto form and enol form) have been studied at low heating temperature (<100℃). It is shown that keto form HPMBP must be isomerized to its enol form in the process of the solid state reaction of keto form HPMBP with Cu(OAc)2.H2O. The mechanisms of these two solid state reactions are discussed.

Key words: ULTRAVIOLET SPECTROPHOTOMETRY, INFRARED SPECTROPHOTOMETRY, ISOMER, PYRAZOLINE P, COPPER ACETATE