Product name:Phenolphthalein
CAS:77-09-8
Molecular Formula:C20H14O4
Formula Weight:318.32
Description:Phenolphthalein is a weak organic acid, at room temperature for white or microband yellow small crystal, odorless, tasteless, difficult to dissolve in water and soluble in alcohol (ethanol), ether. An acid-base indicator is made by dissolving in an alcohol solution, which is colorless in an acidic solution, red in an alkali solution or carbonate solution of alkali metals, but colorless trimetallic salts are formed in a concentrated alkali solution, and the red color fades. Due to this characteristic, it is often used as an indicator for acid-base titration in the laboratory. The range of discoloration is from colorless to red with PH value of 8.2 ~ 10.0. When phenolphthalein reagent drops into water or neutral, acidic aqueous solution, white turbidity will appear, this is because alcohol soluble in water, the reagent is difficult to dissolve in water phenolphthalein precipitation.
The main USES of phenolphthalein are as follows:
1, pharmaceutical industry pharmaceutical raw materials: used for habitual stubborn constipation, tablets, suppositories and other dosage forms.
2, used in organic synthesis: mainly used in synthetic plastics, especially the synthesis of dinitrogen miscellaneous naphthalene poly (aryl ether ketone ketone polymer poly (aryl ether ketone, this kind of polymer because it has excellent heat resistance, water resistance, chemical corrosion resistance, heat aging resistance and good processing formability, made from the fibers, coatings and composite materials such as soon is widely used in electronic appliances, mechanical equipment, transportation, aerospace, nuclear engineering and military and other fields.
3, used for acid-base indicator, non-aqueous titration indicator, reagent for chromatographic analysis.
Phenolphthalein can be prepared by mixing phthalic anhydride with phenol and co-heating sulfuric acid.