Product name:o-Cresolphthalein
CAS:596-27-0
Molecular Formula:C22H18O4
Formula Weight:346.38
Description:O-cresolphthalein is a white or red yellow crystalline powder. Melting point 223-225℃, soluble in ethanol, ethyl ether, glacial acetic acid, slightly soluble in water, soluble in dilute alkali purple, hardly soluble in benzene.
O-cresolphthalein is obtained by condensation of phthalic anhydride and o-toluene. The phthalic anhydride and o-cresol were mixed and heated to melt. Anhydrous zinc chloride was added at 110℃, and the reaction was stirred at 110-115℃ for 12-18h. The remaining o-cresol was expelled by steam. The crude product sodium hydroxide solution was dissolved and filtered. The filtrate is neutralized with dilute hydrochloric acid, and the white crystal is the finished product.
The mixture of o-methylphenol and phthalic anhydride was mixed, and the mixture was slowly heated under agitation until melting, then the fresh anhydrous zinc chloride was rapidly added. The mixture was heated to 105 ~ 110℃ and kept for 5 ~ 6h for condensation reaction:
After the reaction, add a small amount of water, stir to dissolve the precipitation, and then add it to dilute hydrochloric acid. After the precipitation is complete, filter it, wash the precipitation with a small amount of distilled water for several times, grind the precipitation and then add dilute hydrochloric acid to filter it. Add 10% sodium hydroxide solution to the filtered crystallization, stir and heat to dissolve, then add cold distilled water, cool the crystallization, filter, and wash the crystallization with water until qualified. The washing solution was combined with filtrate, and concentrated hydrochloric acid was added to cool and crystallize, filter, and wash until qualified, and then combined with the above crystallization drying to obtain o-cresolphthalein.
Specification:25g
Melting point:223-225 °C
Boiling point:555 °C at 760mmHg
Flash Point:198.8 °C
Density:1.32 g/cm3
Chemical property:white to pink or beige to tan powder.Slightly soluble in water.
Use:As acid-base indicator.