PYROGALLOL RED

Chemical properties

dark brown powder

The Uses of PYROGALLOL RED

Pyrogallol Red is a complexometric indicator for the metal elements molybdenum and copper. Dyes and metabolites.

The Uses of PYROGALLOL RED

The white powdery crystal was made by the superheating of gallic acid. Pyrogallic acid, popularly known as pyro, is one of the earliest developers and its use has spanned three centuries. It was first used in an acid state to physically develop wet collodion negatives. When silver bromide gelatin plates were adopted pyro was used again but in an alkaline state for chemical development. It was used throughout the 20th century and often chosen for the peculiar yellow stain it imparted to gelatin negatives.

What are the applications of Application

Pyrogallol Red is a complexometric indicator for the metal elements molybdenum and copper

Purification Methods

It is recrystallised from aqueous alkaline solution (Na2CO3 or NaOH) by precipitation on acidification, filter it off and dry in a vacuum. [Suk Collect Czech Chem Commun 31 3127 1966, Beilstein 19 H 407, 19 II 417, 19 III/IV 599, 19/10 V 226.]