Patent · US Expired

Production of phthalic anhydride

US3931243A · kind A · utility

5Cited by
4References
8Claims
0Family size

Assignee

Inventors

Key dates

Filing dateJan 28, 1974
Grant dateJan 6, 1976
Priority date—
Expiry dateJan 28, 1994

Classification

  • Technology area (CPC C)Chemistry; Metallurgy
  • CPC primaryC07C51/08
  • WIPO fieldOrganic fine chemistry
  • WIPO sectorChemistry

Abstract

Anhydrides of carboxylic acids, more particularly, of aromatic, naphthenic and saturated aliphatic acids having at least one pair of carboxyl groups attached to adjacent carbon atoms, can be prepared by thermal decomposition of amine salts of the acids, with removal of the amine. The amine salts may be produced by aqueous hydrolysis of the corresponding nitriles, imides, or amides in the presence of an amine, or by hydrolysis to the ammonium salts followed by conversion to the amine salt by stripping off ammonia in the presence of an amine.

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