Silica adsorbent design and process evaluation for recovery of homogeneous catalysts by reverse flow adsorption

The goal of this work is to demonstrate the stability of reverse flow adsorption process for recovery of homogeneous catalysts and to study the influence of catalyst and adsorbent properties for optimizing the RFA process operation. Data used in simulations were obtained from our previous work. Two models are developed to describe the reversible adsorption. One which describes the adsorption of the metal containing species and second model that describes adsorption of the free ligand. It is shown that stable operation is reached, where leaching of metal is prevented. The RFA process can be applied for wide ranges of the catalyst's stability constants [100-1012 (dm3/mol)2] and it is specially applicable for the recovery of homogeneous catalysts that have a low metal concentration. Values of the adsorbent (M = 0.8, = 1850, PeP = 376.4, dp = 100 m and b = 0.5) and the column characteristics (Bo = 1.74 × 104 and N = 6.6 × 104) that provide a sharp concentration profile inside the bed are determined. Simulation of the recovery of Rh catalyst in the BASF hydroformylation process required a total adsorption bed volume of 6% of reactor volume. © 2008 American Institute of Chemical Engineers AIChE J, 2008