10083. Xylenol Blue

Nomenclature

CAS number: 125-31-5
4,4′-(3H-2,1-Benzoxathiol-3-ylidene)bis[2,5-dimethylphenol] S,S-dioxide; p-xylenolsulfonephthalein; 1,4-dimethyl-5-hydroxybenzenesulfonephthalein; α,4,4′-trihydroxy-2,5,2′,5′-tetramethyltriphenylmethane-2″-sulfonic acid γ-sultone.
C23H22O5S; mol wt 410.48.
C 67.30%, H 5.40%, O 19.49%, S 7.81%.

Description and references

Prepd from o-sulfobenzoic acid dichloride or o-sulfobenzoic acid anhydride and p-xylenol in the presence of zinc chloride: Cohen, Biochem. J. 16, 31 (1922).

Chemical structure

Properties

Brown crystals from alcohol.

Use

Indicator, used in 0.02% soln: pH 1.2 red, 2.8 yellow, 9.6 blue.