Process concepts for the transition metal catalyzed syntheses of formic acid and dimethylformamide based on carbon dioxide

In recent years, carbon dioxide has attracted increasing attention as raw material for chemical syntheses [1-3]. In contrast to fossil raw materials as carbon sources, the carbon amounts that are chemically bound as carbon dioxide are nearly inexhaustible. Carbon dioxide is nontoxic, inflammable, and easily accessible. Therefore, syntheses of fine and bulk chemicals based on carbon dioxide possess an enormous economic potential. The chemically inert carbon dioxide can be activated by homogeneous transition metal complex catalysts [4]. This permits a number of various syntheses, for example, of hydrocarbons, alcohols, or carbonates. These syntheses are only profitable if the catalyst separation and recycling can be carried out completely and simply. One approach for this is the liquid-liquid two-phase technique [5]. Here, the catalyst is dissolved in one liquid phase, whereas the starting material(s) and products are retained in a second liquid phase. In this contribution, the development of process concepts for the syntheses of formic acid and dimethylformamide the hydrogenation of carbon dioxide is presented. © 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim.