Hydroformylation of long-chain alkenes with new supported aqueous phase catalysts

In this paper the development and investigation of a new type of immobilized catalyst for the hydroformylation of long-chain alkenes is presented. The catalyst system consisted of the well known metal complex carbonylhydrido-tris-(m-sulfo-triphenylphosphine)-rhodium which was immobilized on activated carbon treated at high temperature. As starting materials I-hexene, 1-decene, 1-tetradecene, 2-hexene and 2,3-dimethyl-2-butene were used. For all linear alpha-olefins the same nliso ratio in the product of 2:1 was determined. The reaction rate decreased with increasing chain length and sterical hindrance of the alkene double bond. All hydroformylation experiments were performed in a stirred semi-batch reactor. Catalyst leaching turned out to be a function of solvent polarity. Using n-heptane as solvent the immobilized catalyst remained stable on the carrier. The activity of the immobilized catalyst decreased compared to the homogeneous catalyst system. Water content was identified to be one of the most significant parameters of the reaction rate. The simulation of experimental data was modelled by a semi-empirical rate law. Within the simulation the reaction scheme consisting of hydroformylation, isomerization and aldol reaction was simultaneously calculated. It was possible to determine the reaction orders of all components, rate constants and the activation energies of all reactions. (c) 2005 Elsevier B.V. All rights reserved.