Hydrogenation of biomass derived oxygenates
Date
2017
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Abstract
Biomass, an abundant, renewable, and near carbon-neutral feedstock, has the potential to supply many valuable chemicals and biofuels and is as an alternative to crude oil feedstocks. Biomass-derived species, however, naturally contain a high oxygen concentration, which lowers the energy density of the biomass-derived molecules, and thus are not feasible for direct use. The development of selective catalytic technology for the removal of this ‘excess’ oxygen from biomass-derived species is essential to making these technologies a practical reality. ☐ At the same time, shale gas production has increased rapidly since 2007 in the U. S. due to the new extraction technologies such as hydraulic fracturing and horizontal drilling. As a clean, inexpensive, and abundant carbon source, methane has attracted scientists all over the world to research C1 chemistry and transform this molecule into more valuable species. ☐ This dissertation focuses on the development of catalytic processes for biomass derived oxygenates upgrading and natural gas conversion into petrochemicals. In this dissertation, three types of heterogeneous catalysts are investigated: catalysts for the hydrodeoxygenation of furfural (Cu supported on silica), catalysts for the selective hydrogenation of aliphatic carboxylic acids to aldehydes (first-row metal oxides), and catalysts for the non-oxidative coupling of methane (based on Mo2C). ☐ The selective hydrodeoxygenation of furfural to 2-methylfuran was investigated over iron-promoted copper catalyst as the first part of the thesis. Iron was added as a promoter to the silica supported copper catalyst and the roles that the iron play in this reaction were identified with various characterization methods. In addition, the selectivity of this reaction was investigated under different pre-treatment and reaction conditions. ☐ The selective hydrogenation of carboxylic acids to the corresponding aldehydes was carried out on chromium containing catalyst. Different types of chromium oxide catalysts from different synthetic methods were evaluated with a series of (small) carboxylic acids of propionic acid (C3) to hexanoic acid (C6). The active phase of the catalyst was characterized and the reaction mechanism was studied further. Finally, a few kinetic studies were performed to validate the reaction rate expression derived from the proposed mechanism. ☐ As a study for natural gas utilization, the methane coupling reaction to ethylene in a single step and oxidants free condition was investigated with Mo2C/ZSM-5 catalyst. The effect of zeolite acidity was investigated in the methane activation reaction to control the products selectivity. A boron containing zeolite was synthesized and the zeolite structure evolution was investigated through the reaction. The active molybdenum species were characterized with surface and bulk techniques to find out the surface reaction with methane.