diketone type chelating ligands have high coordinative activity and selectivity, and are widely applied in analytical chemistry. In order to obtain profounder understanding to the properties of bis(4 acylpyrazolone 5), A new 4 acylpyrazol 5 one derivative (H 2BPMPP) was syntheszed, which contains a heterocyclic ring between two 1 phenyl 3 methyl 4 acylpyrazol 5 one rings. The new compound was characterized by element analyses, UV, IR and 1H NMR spectra. The equilibrium of the keto enol tautomerism was studied. The results show that a lower dielectric constant of solvent favors the enol form which has a higher λ max . Due to special merits of paraffin wax, the solid liquid extraction behavior of Ce(Ⅲ) with molten paraffin wax as a diluent was also investigated at higher temperature. The value of the pH 1/2 was 3.19 and the value of log K ex was 3.467. The chemical composition of the complex was obtained by the slope analysis method. diketone type chelating ligands have high coordinative activity and selectivity, and are widely applied in analytical chemistry. In order to obtain profounder understanding to the properties of bis (4 acylpyrazolone 5), A new 4 acylpyrazol 5 one derivative (H 2BPMPP) was synthesized, which contains a heterocyclic ring between two 1 phenyl 3 methyl 4 acylpyrazol 5 one rings. The new compound was characterized by element analyzes, UV, IR and 1H NMR spectra. The equilibrium of the keto enol tautomerism was studied. The results show that a lower Dielectric constant of solvent favors the enol form which has a higher λ max. Due to special merits of paraffin wax, the solid liquid extraction behavior of Ce (Ⅲ) with molten paraffin wax as a diluent was also investigated at higher temperature. The value of the pH 1/2 was 3.19 and the value of log K ex was 3.467. The chemical composition of the complex was obtained by the slope analysis method.