Application of a structured multifunctional reactor for the oxidation of a liquid organic feedstock

Expts. are performed in a structured packed bed reactor that was developed for the selective oxidn. of org. liqs. to produce pharmaceutical products. Mol. oxygen is used as the oxidant, providing a "cleaner processing route", than in established methods. The structured assembly consists of an integrated heat exchange system, a gas/liq. mixing zone, and provision for reactant injection. To illustrate the application, the selective oxidn. of benzyl alc. to benzaldehyde was studied. The reactor consisted of parallel reaction channels (10 cm long and square shaped) that were packed with Ru/Al2O3 (0.9 wt% Ru) catalyst particles. From expts. in three different sizes of channel: 2 mm * 2 mm, 3 mm * 3 mm, and 5 mm * 5 mm (at P = 8 bar, T = 388 K, with liq. and gas flows L = 3.2 kg m-2 s-1, G = 1.35 * 10-2 kg m-2 s-1), in a short 10 cm length of channel, a product yield up to ca. 29% (with min. 99.5% selectivity) could be obtained. Conversions were highest in the 3 mm * 3 mm channel. From the expts. with the reactor mounted both in horizontal and vertical planes, gravitational influences are minor. The choice of solvent was shown to affect the yield of benzaldehyde. The highest yield was with toluene; the application of dioxane/water mixt. (70/30 by vol.) and N-Me pyrrolidone (NMP) not only decreased the yield by factor 2, but NMP also caused deactivation of the catalyst. Preliminary results are presented of work with Pt/C (Pt 3 wt%) catalyst. [on SciFinder (R)]