Degussa Aktiengesellschaft

Rainer Sanzenbacher

Thomas Lehmann

Christoph Weckbecker

Martin Hateley

Jürgen Bilz

Dieter Engel

Christian Reufer

A process for the preparation of &#x3b1;-substituted carboxylic acids from the series including &#x3b1;-hydroxycarboxylic acids and N-substituted-&#x3b1;-aminocarboxylic acids by cathodic carboxylation with carbon dioxide of a compound corresponding to the general formula R&#x2014;C(&#x2550;X)Rwhich is constituted by aldehydes, ketones or N-substituted imines. In the past, that carboxylation has taken place in an undivided electrolytic cell with the use of a sacrificial anode. As described herein, the carboxylation takes place in the absence of a sacrificial anode in an electrolytic cell divided by a separator, at a diamond film cathode. The anode is formed of a material which is stable under electrolytic conditions; in particular, it is a diamond film electrode. The catholyte includes an organic solvent and a conducting salt.

Process for the preparation of &#x3b1;-substituted carboxylic acids from the series comprising &#x3b1;-hydroxycarboxylic acids and n-substituted-&#x3b1;-aminocarboxylic acids

A process for the electrolytic removal of contaminants from gases, wherein a gas and a liquid electrolyte are passed co- or counter-currently through a fixed bed electrode of an electrolysis cell which has a counterelectrode separated from the fixed bed electrode by a separator and the contaminant is electrochemically converted at an effective cell voltage. Such cells have hitherto been operated in a flooded state. The degree of purification may be substantially increased if the fixed bed electrode is operated as a trickle bed reactor.

Process for the purification of gases

Growing community of inventors

Geinhausen, Germany

Rainer Sanzenbacher