Water → HCID 131710714, compound

Participants

Reaction Steps

30 Parts of crude flavanthrone were dissolved in 300 parts of concentrated sulfuric acid. 36 Parts of water were added dropwise at 50°-70° C, the flavanthrone-sulfate crystals formed were suction-filtered via an acid-resistant filter at room temperature and washed with about 150 parts of 80% sulfuric acid. The filter cake was introduced while stirring into 300 parts of water, the dyestuff was filtered and washed with water until free from acid. 63 Parts of an aqueous filter cake were obtained having a content of solid body of 43%.

Provenance & Evidence