Phenylbutazone, chemically named 1, 2-diphenyl4-n-butylpyrazole-3, 5-diketone, white or white-like crystalline powder; Odorless, slightly bitter. Soluble in acetone or chloroform, soluble in ethanol or ether, almost insoluble in water; Dissolve in alkali hydroxide solution. The molecular formula is C19H20N2O2, molecular weight is 308.37400, density is 1.173g/cm3, melting point is 104-107 °C, boiling point is 424.9 C at 760mmHg.