Article · Wikipedia archive · Last revised Jul 19, 2026

Phthalein dye

Phthalein dyes are a class of dyes mainly used as pH indicators, due to their ability to change colors depending on pH. They are formed by the reaction of phthalic anhydride with various phenols. They are a subclass of triarylmethane dyes.

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Chemical structure of phenolphthalein, a common phthalein dye source ↗

Phthalein dyes are a class of dyes mainly used as pH indicators, due to their ability to change colors depending on pH.1 They are formed by the reaction of phthalic anhydride with various phenols. They are a subclass of triarylmethane dyes.

Common phthalein dyes include:

See also

See also

References

References

  1. Sabnis, Ram W. (2010). "Phthalein Dyes". Kirk-Othmer Encyclopedia of Chemical Technology. doi:10.1002/0471238961.phthsabn.a01. ISBN 978-0471238966.