On December 12, 2012, the Bioenergy Technologies Office hosted a webinar titled, “Upgrading Renewable and Sustainable Carbohydrates for the Production of High Energy Density Fuels.” Featured presenters, John Gordon and Pete Silks of Los Alamos National Laboratory, discussed how improvements in catalysis science are leading to more efficient conversion of non‐food biomass into transportation fuels and chemical feedstocks. Along with a question and answer session, Dr. Gordon and Dr. Silks explained how the increased efficient production can potentially reduce our dependence on foreign oil and ensure the long term availability of renewable starting materials for consumer products while simultaneously reducing the production of harmful greenhouse gasses. Earlier this month, they, along with their Los Alamos National Laboratory team members, also had an article published on their research.
The article focuses on one aspect of non‐food biomass transformation that has received comparatively little attention: furan rings. For more than a century, chemists have focused largely on adding functionality to molecules, not removing it, however, the Los Alamos Team’s research focuses on doing just that.
In their article, “Functional group dependence of the acid catalyzed ring opening of biomass-derived furan rings: an experimental and theoretical study,” the Los Alamos team explains that furan rings are ubiquitous in cellulose/carbohydrate derived fuel precursors, and opening these rings is a necessary step in the production of energy dense alkanes suitable as fuels (see figure). Currently, these rings are typically first hydrogenated and then opened (Path A), requiring high temperatures and very high pressures, which is not favorable from an energy efficiency standpoint.
In Path A, above, opening the furan ring requires comparatively extreme conditions (high temperatures) and numerous reagents. In contrast, Path B allows the direct ring opening of the furan ring and is a good first step toward fuels since it can be performed at relatively mild conditions (80°C) using the common reagent HCl, a catalyst.(Illustration courtesy of Los Alamos National Laboratory.)
However, the Los Alamos Team has investigated an alternative approach to opening the furan rings using a simple catalyst, hydrochloric acid, in low concentrations. The catalytic ring‐opening of the furan groups occurs at mild temperatures (between 80°C and 100°C), to produce precursors to linear alkanes. The process was tested on several biomass‐derived molecules, and the mechanism was studied with the help of density functional theory (DFT) calculations. While this study does not describe an end‐to‐end solution in terms of alkane production, it provides important insight into one of the critical steps in fuels synthesis from biomass and may enable the design of better catalysts and processes for transformation of biomass into fuels and commodity chemicals on large scales.
To learn more, check out the Los Alamos Team’s article in the Catalysis Science and Technology journal or view the December 12th webinar.