Thymolphthalexone


Thymolphthalexone is a chemical compound from the group of iminodiacetic acid derivatives of thymolphthalein. Its chemical formula is.
This is a metallochromic indicator widely used in complexometric titrations, particularly for the determination of transition metals. The compound features a thymolphthalein-derived core linked to aminopolycarboxylic acid functional groups. This hybrid architecture grants the compound the ability to preferentially bind specific metal ions through coordinated interactions.

Synthesis

Thymolphthalexone can be obtained by Mannich condensation of formaldehyde and iminodiacetic acid with thymolphthalein.

Physical properties

Thymolphthalexone forms a white crystalline powder soluble in water and organic solvents.

Uses

Thymolphthalexone and its sodium salt are used as an indicator or photometric reagent for alkaline metal ions, such as those of calcium, strontium, barium, and others.