A micro-structured single channel falling film is used for gas–liquid contacting. A small falling angle of 7.5° is used to ensure long residence time in the range 3–22 min, even with low viscosity solvents such as methanol. Using this device, a screening of molecular catalysts of the type rhodium/chiral diphosphines for the asymmetric hydrogenation of Methyl-Z-(α)-acetamidocinamate and similar substrates has been performed. The very small reacting volume of 14 μl leads to an average inventory of Rh/test as low as 0.1 μg. Comparisons with traditional batch experiments are provided.
