HYDROGENATION AND METHYLATION OF DODECYLNITRILE IN THE PRESENCE OF SUPPORTED COPPER CHROMIUM CATALYSTS .2. CATALYTIC PROPERTIES

Non-stoichiometric copper chromite catalysts are active and selective in the synthesis of dimethylalkylamines, dialkylamines or dialkylmethy lamine from fatty acids, esters or nitriles. These specific properties result from the association of copper and chromium which increases th e metal surface area, hydrogen adsorption, and storage and acidity (es pecially of strong acid sites). Nevertheless these mixed catalysts, wh ich are more stable than monometallic ones, are modified during the ca talytic reaction, as is selectivity. For example ammonia (and/or water ) are strong inhibitors and excess hydrogen is necessary to reduce the adsorption of reaction products and the transformation of catalysts. In our study the main intermediate species were identified and selecti vity modifications were examined in relation to the surface and bulk p hysico-chemical properties.