Scientific name "3, 3-bis (4-hydroxyl-5-isopropyl-2-methyl phenyl) -phthalide". An organic reagent. Chemical formula C28H30O4, molecular weight 430.54. White crystalline powder. Soluble in ether, acetone, sulfuric acid and alkali solution, insoluble in water. Commonly used as acid base indicator, the pH color range is 9.4-10.6, colorless to blue color. Often used to make a 90% ethanol solution of 0.1%. It is also often combined with other indicators into a gentle indicator, so that its color range is narrower, more clearly observed. White or yellowish acicular crystal, soluble in ethanol and acetone, insoluble in water, red in sulfuric acid, blue in dilute alkali

C28H30O4 molecular weight 430.54 CAS number 125-20-2 EINECS number 204-729-7 melting point 251-253℃ water soluble insoluble density 0.92g/mL(25℃) white or yellow needle crystal flash point 74℉