UMass-Amherst Team Solves Mystery of Cellulose Chains Breakdown
by Jim Lane (Biofuels Digest) What exactly happens in depolymerization, as hydrogen bonds break down? How could that revolutionize the process of making fuels, solvents, thinners, lacquers or paints out of biobased materials?
Before one is able to arrange a global bioeconomy, first there’s a little rearranging to do with the underlying biomass. – transforming it from algae, or plants or trees into products for everyday life.
There are three ways to do that.
One – fractionation…
… The move into extracting sugars from cellulose and hemicellulose – the cellulosic revolution – has given hope to the idea of utilizing parts of plants not otherwise claimed for food or feed. But there have been delays and headaches in the fantastically difficult science of extracting and fermenting those sugars, at scale, at affordable costs.
Which brings us to door number three – the thermo-chemical path. In this case, we heat up biomass until the hydrogen bonds that hold it together start to modify and break down – and from there we get a soup of material that can be repurposed into a huge range of products.
The process is called depolymerization …
…(Y)ou can think of it as something not entirely unlike melting ice. At the freezing point of water, hydrogen bonds rigidly hold the water molecules together – when heat is applied, the bonds loosen up and water molecules begin to flow as a liquid, and eventually radiate as a gas.
Those bonds can be pretty amazingly strong, as anyone who has ever foolishly stuck their tongue-tip to a freezing pole in wintertime can attest.
Melting water is pretty simple, it happens the same way every time. But the process of breaking the biomass bonds has been unpredictable, with different outcomes derived from different heating protocols.
…Reporting in the current issue of the Journal of the American Chemical Society, theoretical chemist Scott Auerbach, chemical engineers George Huber and Paul Dauenhauer, and colleagues at the University of Massachusetts Amherst have, for the first time, modeled at the molecular level the activation energies needed for the chemical reaction known as “fast pyrolysis” to proceed in cellulose. READ MORE Abstract