Preparation of benzaldehyde dialkyl acetals

US5507922A · kind A · utility

Assignee

• BASF SE

Inventors

• Dieter Hermeling · Haßloch, DE
• Heinz Hannebaum · Ludwigshafen, DE
• Hartwig Voss · Bischofswerda, DE
• Andreas Weiper-Idelmann · Waldsee, DE

Key dates

• Filing date: Aug 11, 1994
• Grant date: Apr 16, 1996
• Expiry date: Aug 11, 2014

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C25B3/23
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

Benzaldehyde dialkyl acetals of the general formula I ##STR1## where R.sup.1 is C.sub.1 -C.sub.6 -alkyl, R.sup.2 is C.sub.1 -C.sub.6 -alkyl, C.sub.1 -C.sub.6 -alkoxy, halogen, cyano or carboxyalkyl where the alkyl group is of 1 to 6 carbon atoms, n is an integer of from 1 to 3 and the radicals R.sup.2 may be identical or different when n is >1, are prepared by electrochemical oxidation of a substituted toluene compound of the general formula II ##STR2## by a process in which a substituted toluene compound II is oxidized in the presence of an alkanol R.sup.1 --OH and of an auxiliary electrolyte in an electrolysis cell, the reaction solution thus obtained is let down outside the electrolysis cell to a pressure which is from 10 mbar to 10 bar lower than the pressure in the electrolysis cell and PA1 A) in the batchwise procedure, the gas released from the reaction solution on letting down the latter is separated off and the reaction solution is recycled at least once to the electrolysis cell, subjected to electrolysis, let down, separated from the released gas and then worked up to obtain the product, or PA1 B) in the continuous procedure, some of the reaction solution is worked up to …