Rational scale-up of catalytic hydrogenation involving slowly dissolving reactants

Based on an experimental campaign, a model is developed for scaling up a fed-batch catalytic hydrogenation, characterized by a slow dissolution of the reagent. The model considers all mass transfer rates across the 4 phases, with solid reagent dissolution identified as the limiting factor. Chemical kinetics were identified for 7 reactions using laboratory scale data with transients in temperature and stirring. The model developed at 0.5 L scale, accounts for reactor size and impeller type; validation was performed from data from a 170 L reactor. Sensitivity analysis on product purity, batch and dissolution time at pilot scale was performed. Higher temperature shortens both times, but promotes formation of undesirable intermediates. Stirring positively affects solid dissolution and batch time, with more impact at lower temperatures. The optimal operating point was found at a temperature of 65% of the maximum allowed (80 degrees C), allowing for lower stirring rate and reduced power consumption.