(598d) An Approach for Efficient Conversion of Carbohydrates to Value Added Products Using Metal Coated Polymeric Membranes

One of the most important challenges in the development of a biorefinery is to develop a facile conversion technology capable of converting the renewable carbon to high value chemicals. Conventional hydrogenation technology employs slurry-phase systems in which gaseous hydrogen is contacted with a solid catalyst dispersed in a liquid reactant. These three-phase systems suffer from the vanishingly small solubility of hydrogen in liquids. Operation at extreme pressures (frequently in excess of 100 atm) is employed to overcome these thermodynamic limitations. Maintaining high hydrogen coverage at the catalyst surface favors hydrogenation reactions over side reactions.

 The research presented here focuses on developing membrane reactor hydrogenation technology capable of operating at modest hydrogen pressures while simultaneously providing rapid hydrogen delivery to the catalyst surface. Specifically, the membrane reactor employed is designed such that one surface of the membrane is decorated with metal catalyst sites. This surface of the catalyst is contacted by the substrate-containing liquid to be converted. In this study, aqueous phase hydrogen of lactic acid, an intermediate of significant importance to the biorefining field was investigated.  Hydrogen is supplied on the permeate side of the membrane and is transferred to the catalyst surface by the imposed chemical potential driving force.

 The membranes used in the reactor are integrally skinned asymmetric Polyetherimides with thin, defect-free surface layers. Ruthenium was employed as the catalyst for the hydrogenation reaction and applied via spin coating.

 This study can thereby help in contributing towards efficient processing conditions for obtaining value added products from renewable carbon.