Patent · US Expired

Process for removing 1,4-naphthoquinone from phthalic anhydride

US4026770A · kind A · utility

1Cited by

0References

6Claims

0Family size

Assignee

BAYER HEALTHCARE LLC · DE

Inventors

Gerhard Scharfe · Leverkusen, DE
Rupert Wenzel · Leverkusen, DE
Wolfgang Biedermann

Key dates

Filing date	Oct 29, 1975
Grant date	May 31, 1977
Priority date	—
Expiry date	Oct 29, 1995

Classification

Technology area (CPC C)Chemistry; Metallurgy
CPC primaryC07C51/42
WIPO fieldOrganic fine chemistry
WIPO sectorChemistry

Abstract

1,4-NAPHTHOQUINONE IS REMOVED FROM PHTHALIC ANHYDRIDE BY HEATING WITH ELEMENTARY SULFUR AT TEMPERATURES IN THE RANGE OF FROM 200.degree. TO 300.degree. C.

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