Catechol violet

Structural formula
General
Surname	Catechol violet
Molecular formula	C 19 H 14 O 7 S
Brief description	dark green odorless solid
External identifiers / databases
CAS number 115-41-3 EC number 204-088-3 ECHA InfoCard 100.003.717 PubChem 66993 Wikidata Q910031
properties
Molar mass	386.36 g mol −1
Physical state	firmly
Melting point	185 ° C
solubility	bad in water (1 g l −1 )
safety instructions
GHS labeling of hazardous substances no GHS pictograms H and P phrases H: no H-phrases P: no P-phrases
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Pyrocatechol violet is a chemical compound from the group of triphenylmethane dyes . It is used as an indicator substance which changes its color from red in the pH range <0, via yellow in the range from 2–8 to purple in the range around 8 and red-violet in the basic range. It forms complex compounds with metal ions .

Extraction and presentation

Catechol violet can be obtained by reacting catechol with 2-sulfobenzoic anhydride .

use

Catechol violet solutions (e.g. EDTA ) can be used for the determination of many metals ( titration for chelates and other complexes ), especially for the detection of tin . The chelates formed by metals with catechol violet are generally blue to blue-violet in color.

Individual evidence

1. ↑ ^{a b c} data sheet Catechol Violet at AlfaAesar, accessed on December 7, 2019 ( PDF )(JavaScript required) .
2. ↑ ^{a b c} Datasheet Pyrocatechol Violet, suitable for indicator at Sigma-Aldrich , accessed on December 7, 2019 ( PDF ).
3. ↑ Google Patents: CN103387563A - Preparation method for catechol violet - Google Patents , accessed December 7, 2019