Study offers insight into converting wood to bio-oil

Dec 14, 2012 by Mick Kulikowski
A paper that offers insight into converting wood to useful bio-oils appears as the cover article in the Journal of Physical Chemistry A.

(—New research from North Carolina State University provides molecular-level insights into how cellulose – the most common organic compound on Earth and the main structural component of plant cell walls – breaks down in wood to create "bio-oils" which can be refined into any number of useful products, including liquid transportation fuels to power a car or an airplane.

Using a supercomputer that can perform functions thousands of times faster than a standard desktop computer, NC State chemical and biomolecular engineer Dr. Phillip Westmoreland and doctoral student Vikram Seshadri calculate what's occurring at the molecular level when wood is rapidly heated to high temperatures in the absence of oxygen, a decomposition process known as pyrolysis.

A paper that offers insight into converting wood to useful bio-oils appears as the cover article in the Journal of Physical Chemistry A.

The results, which could help spur more effective and efficient ways of converting farmed and waste wood into useful bio-oils, appear in a feature article on the cover of the Dec. 13 print edition of the A.

Much of the energy that can be extracted from wood exists in the cellulose found in cell walls. Cellulose is a stiff, rodlike substance consisting of chains of a specific type of a simple sugar called glucose. The paper describes a mechanism for how glucose decomposes when heated. The mechanism is somewhat surprising, Westmoreland says, because it reveals how and even the glucose itself can trigger this decomposition.

"The calculations in the paper show that although the decomposition products and rates differ in glucose and cellulose, the various elementary steps appear to be the same, but altered in their relative importance to each other," Westmoreland says.

Knowing the specifics of the will allow researchers to make predictions about the ease of extracting energy from different types of wood from various soil types.

The researchers are now conducting experiments to verify their calculations.

Explore further: 'Invisible' protein structure explains the power of enzymes

More information: Concerted Reactions and Mechanism of Glucose Pyrolysis and Implications for Cellulose Kinetics

Authors: Vikram Seshadri and Phillip Westmoreland, North Carolina State University

Published: Dec. 13, 2012, in Journal of Physical Chemistry A

Abstract: Concerted reactions are proposed to be keys to understanding thermal decomposition of glucose in the absence of ionic chemistry, including molecular catalysis by ROH molecules such as H2O, other glucose molecules, and most of the intermediates and products. Concerted transition states, elementary-reaction pathways, and rate coefficients are computed for pyrolysis of ?-D-glucose (?-Dglucopyranose), the monomer of cellulose, and for related molecules, giving an improved and elementary-reaction interpretation of the reaction network proposed by Sanders et al. (J. Anal. Appl. Pyrolysis, 2003, 66, 29?50). Reactions for ring-opening and formation, ring contraction, retro-aldol condensation, keto?enol tautomerization, and dehydration are included. The dehydration reactions are focused on bicyclic ring formations that lead to levoglucosan and 1,6-?-D-anhydrousglucofuranose. The bimolecular ROH-assisted reactions are found to have lower activation energy compared to the unimolecular reactions. The same dehydration reaction to levoglucosan should occur for cellulose going to cellosan (e.g., cellotriosan) plus a shortened cellulose chain, a hypothesis supported by the very similar activation energies computed when alternate groups were substituted at the C1 glycosidic oxygen. The principles of Sanders et al. that distinguish D-glucose, D-fructose, sucrose, and cellulose pyrolysis prove useful in providing qualitative insights into cellulose pyrolysis.

Related Stories

'Mini-cellulose' molecule unlocks biofuel chemistry

Feb 16, 2012

A team of chemical engineers at the University of Massachusetts Amherst has discovered a small molecule that behaves the same as cellulose when it is converted to biofuel. Studying this 'mini-cellulose' molecule reveals for ...

Improved Reaction Data Heat Up the Biofuels Harvest

Aug 06, 2008

High food prices, concern over dwindling supplies of fossil fuels and the desire for clean, renewable energy have led many to seek ways to make ethanol out of cellulosic sources such as wood, hay and switchgrass. ...

Wood completely broken down into its component parts

Oct 24, 2012

Crude oil is getting scarce. This is why researchers are seeking to substitute petroleum-based products - like plastics - with sustainable raw materials. Waste wood, divided into lignin and cellulose, could ...

Recommended for you

What makes fireflies glow?

Jul 01, 2015

As fireflies are delighting children across the country with their nighttime displays, scientists are closing in on a better understanding of how the insects produce their enchanting glow. They report in ...

Scientists unravel elusive structure of HIV protein

Jul 01, 2015

HIV, or human immunodeficiency virus, is the retrovirus that leads to acquired immunodeficiency syndrome or AIDS. Globally, about 35 million people are living with HIV, which constantly adapts and mutates ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.