Process for purifying sterically hindered 4-amino piperidines

US6011157A · kind A · utility

Assignee

• BASF SE

Inventors

• Manfred Julius · Schifferstadt, DE
• Harald Rust · Bochum, DE
• Alfred Krause · Speyer, DE
• Hardo Siegel · Speyer, DE
• Wolfgang Siegel · Schifferstadt, DE
• Tom Witzel · Ludwigshafen, DE

Key dates

• Filing date: Nov 12, 1998
• Grant date: Jan 4, 2000
• Expiry date: Nov 12, 2018

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07D211/56
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A process for purifying crude piperidines of the formula I ##STR1## where R.sup.1 to R.sup.4 are C.sub.1 -C.sub.6 -alkyl, or R.sup.1 and R.sup.2 and/or R.sup.3 and R.sup.4 together are a CH.sub.2 -chain of 2 to 5 carbons, which comprises, in a first step, removing high-boiling substances and, if present, water from the crude piperidines by distillation; in a second step, adding from 0.01 to 5% by weight, based on the product of the first step, as a reducing agent; and, in a third step, isolating the piperidines by distillation.