Patent · US Expired

Process for the preparation of 2,3,4,5-tetrafluorobenzene derivatives

US6613948B1 · kind B1 · utility

0Cited by

3References

9Claims

0Family size

Assignee

BAYER HEALTHCARE LLC · DE

Inventors

Otto Neuner
Norbert Lui · Odenthal, DE
Dietmar Bielefeldt · Ratingen, DE
Michael Holzbrecher · Engelskirchen, DE

Key dates

Filing date	Sep 14, 1998
Grant date	Sep 2, 2003
Priority date	—
Expiry date	Feb 1, 2020

Classification

Technology area (CPC C)Chemistry; Metallurgy
CPC primaryC07C253/30
WIPO fieldOrganic fine chemistry
WIPO sectorChemistry

Abstract

2,3,4,5-tetrafluorobenzene derivatives can be obtained in a particularly advantageous manner by reacting the corresponding chlorobenzene or (chloro, fluoro)-benzene derivatives with a fluorinating agent in the presence of a solvent and a catalyst at elevated temperature, which comprises carrying out the reaction initially under temperature and pressure conditions such that the respective 2,3,4,5-tetrafluoro-benzene derivative continuously distills off through a column, and subsequently setting temperature and pressure conditions such that residual fractions of the 2,3,4,5-tetrafluorobenzene derivative distill off with the corresponding 2,3,4-trifluoro-5-chloro compound.

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