Laccaic acid

Description

A red dyestuff that is the primary colorant in Lac dye. Laccaic acid is an oxy-anthracinone carbon acid. It is extracted from the raw sticklac during the Shellac purification process using a dilute solution of Sodium carbonate.

Synonyms and Related Terms

lac dye; Natural Red 25; CI 75450

Physical and Chemical Properties

• Laccaic acid is soluble in methanol (dries to form needle-like crystals).
• Composition = C20H14O10

Resources and Citations

• The Merck Index, Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983 Comment: entry 5342

• Thomas B. Brill, Light Its Interaction with Art and Antiquities, Plenum Press, New York City, 1980

• The Dictionary of Art, Grove's Dictionaries Inc., New York, 1996 Comment: 'Pigments'

• Judith Hofenk-de Graaff, Natural Dyestuffs: Origin, Chemical Constitution, Identification, Central Research Laboratory for Objects of Art and Science, Amsterdam, 1969