Researchers at the University of Wisconsin in Madison have discovered a new and more efficient way to transform raw cellulosic biomass into a energy-rich biofuel with far-reaching implications. This breakthrough, outlined in the Journal of the American Chemical Society, involves subjecting untreated inedible biomass to a new two-step chemical process. It marks the first time that raw biomass has been used as the basic source material in this particular type of conversion.
According to Ronald Raines, a professor in the Department of Biochemistry and the Department of Chemistry at Wisconsin, the first and most critical step involves converting the cellulose in this biomass into a "platform" chemical, 5-hydroxymethylfurfural (HMF). This is done by treating it with a unique and patented solvent mix that was developed by Raines and Joseph Binder, a graduate student and fellow researcher. The HMF then undergoes a follow-up procedure which transforms it into a high-energy biofuel known as 2.5-dimethylfuran (DMF).
Although primary research was done using corn stalks and leaves, the team also experimented with pine sawdust and Raines believes that almost any type of biomass would work. "Other groups have demonstrated some of the individual steps involved in converting biomass to HMF, starting with glucose or fructose. What we did was show how to do the whole process in one step, starting with biomass itself." While the solvent used in this process is strong enough to dissolve cotton balls, which are pure cellulose, Raines points out that the system is a simple one that's "not corrosive, dangerous, expensive or stinky."
So far, this new process has yielded a nine-percent cellulose-DMF conversion ratio. However, that figure is expected to climb as the second stage of the process is optimized. Raines claims that DMF, which has already been employed as a gasoline additive, offers numerous advantages over ethanol. Most notably, it has the same energy content as gasoline, is fully compatible with the existing delivery and pumping infrastructure and does not mix with water.