The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 24, 1998
Filed:
Mar. 18, 1993
Applicant:
Inventors:
Assignee:
Ciba Specialty Chemicals Corporation, Tarrytown, NY (US);
Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
C07D / ;
U.S. Cl.
CPC ...
546184 ; 546242 ;
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.