Kinetic Studies Of Biomass Hydrodeoxygenation In A Continuous Flow Reactor
Hydrodeoxygenation (HDO) of 5-hydroxymethylfurfural (HMF) has received a great deal of attention in the past few years because of its importance for converting biomass into petrochemical replacements. Previously, most studies on liquid-phase HDO have been performed only in batch reactors. The present work investigates the HDO reaction in a self-designed flow reacting system, which is demonstrated to be a powerful tool for kinetic studies. The data indicate that the HDO of HMF follows a sequential scheme, with HMF first reacting to partially hydrogenated intermediates. These intermediate products then form DMF, which in turn reacts further to undesired products. The HDO performance has been investigated over a large number catalysts in the flow reactor. Monometallic catalysts (Pt, Pd, Ni, Co, Ru, Ir, etc.) are generally found to be unselective, due to the over-hydrogenation of DMF through ring-opening or ring-hydrogenation. By contrast, bimetallic catalysts, especially with well-controlled particle size and metal composition, are observed to be highly selective in the HDO of HMF. Nearly 100% yields of DMF can be achieved over Pt3Co2, Pt3Ni, Pt2Zn and PtCu nanocrystal catalysts. Theoretical calculations indicate that the binding configuration of furanic intermediates change on bimetallic surfaces compared to monometallic catalyst, leading to different reaction pathways. This thesis work provides a general strategy for improving the HDO selectivity from HMF.