Patent · US Expired

Process for the preparation of 4-hydroxy-1,2,2,6,6,-pentamethylpiperidine

US5840905A · kind A · utility

1Cited by

5References

15Claims

0Family size

Assignee

Ciba Specialty Chemicals Corporation · US

Inventors

Karl Stephan Nitsche · Bensheim, DE
Walter Wolf · Backnang, DE
Joachim Fries · Bensheim, DE

Key dates

Filing date	Mar 18, 1993
Grant date	Nov 24, 1998
Priority date	—
Expiry date	Mar 18, 2013

Classification

Technology area (CPC C)Chemistry; Metallurgy
CPC primaryC07D211/46
WIPO fieldOrganic fine chemistry
WIPO sectorChemistry

Abstract

A process for the preparation of 4-hydroxy-1,2,2,6,6-pentamethylpiperidine (HPMP) from 4-oxo-2,2,6,6-tetramethylpiperidine (TAA) is described, in which TAA is first reduced to 4-hydroxy-2,2,6,6-tetramethylpiperidine (HTMP) by means of catalytic hydrogenation in water, the resulting crude solution, if desired after concentration by distillation, is reacted with formaldehyde or paraformaldehyde in at least 20% molar excess, and with formic acid, and the crude product melt separated from the reaction mixture is worked up by distillation.

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