Location: Renewable Product Technology Research2013 Annual Report
1a. Objectives (from AD-416):
Develop an understanding of the catalyst characteristics that correlate to the linear/ring ratio in the dehydration of 1,2,6-hexanetriol, and a mechanistic model for the 1,2,6-hexanetriol dehydration reaction to determine the key step(s) that dictate this selectivity. Extend the dehydration experiments to other polyhydroxylated reactants, and develop an overarching framework for how polyhydroxylated reactants dehydrate as a function of key catalyst characteristics.
1b. Approach (from AD-416):
Screen catalysts in which hydrogenation metals and acid groups are both present to determine the extent to which we can manipulate the linear/ring ratio in the dehydration of 1,2,6-hexanetriol. Additionally, we plan to examine some metal oxide materials. Simultaneously, we will initiate an ab initio computational study to understand the energetics of the possible competing dehydration pathways. Once we have established the key chemistry rules dictating how catalysts can manipulate the relative linear/ring selectivity, we will extend the experimental portion of the work to examine a broader class of polyhydroxylated molecules.
3. Progress Report:
The production of bio-based chemicals is needed in the further development of the biorefining industry. The objective of this research is to develop an understanding of the catalyst characteristics that correlate to the linear/ring ratio in the dehydration of 1,2,6-hexanetriol, and a mechanistic model for the 1,2,6-hexanetriol dehydration reaction to determine the key step(s) that dictate this selectivity. This research will also be extended to the dehydration of other polyhydroxylated reactants. In FY13, ARS Renewable Product Technology Research Unit scientists at the National Center for Agricultural Utilization Research, Peoria, IL, made significant progress toward this objective, as demonstrated by the following activities. Synthesis of 1,2,omega-triols (where omega=4, 5, 6 and 7). Pulse studies with these triols demonstrated that hydroxyaldehydes are a major dehydration product. This work has potential to improve production of value-added chemicals from biomass by improving the selectivity of the removal of oxygen from structurally complex feedstocks.