Patent · US Expired

Process for the preparation of lithium salts of anionic dyes by reacting the calcium salts with lithium sulfate or lithium hydrogen sulfate

US4707545A · kind A · utility

7Cited by
8References
18Claims
0Family size

Assignee

Inventors

Key dates

Filing dateNov 26, 1985
Grant dateNov 17, 1987
Priority date—
Expiry dateNov 26, 2005

Classification

  • Technology area (CPC C)Chemistry; Metallurgy
  • CPC primaryC09B69/02
  • WIPO fieldBasic materials chemistry
  • WIPO sectorChemistry

Abstract

Lithium salts of anionic dyes are prepared by first converting another salt of this anionic dye in aqueous solution or suspension by means of a compound which releases calcium ions into the water-insoluble or sparingly water-soluble calcium salt of the dye, which is separated from the aqueous medium and is then converted to an aqueous suspension by treatment with lithium sulfate or lithium hydrogensulfate or a mixture thereof in an equivalent amount of each or in an excess of up to 10% into its lithium salt.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.