Thymolphthalein is a phthalein dye used as an acid–base (pH) indicator.
Thymolphthalein is a phthalein dye used as an acid–base (pH) indicator. Its transition range is around pH 9.3–10.5. Below this pH, it is colorless; above, it is blue.
The molar extinction coefficient for the blue thymolphthalein dianion is 38,000 M−1 cm−1 at 595 nm.Thymolphthalein is also known to have use as a laxative[2] and for disappearing ink.
THYMOLPHTHALEIN COMPLEXON AR