“A team of researchers from Purdue University’s Center for Direct Catalytic Conversion
of Biomass to Biofuels, or C3Bio, developed a process that uses a chemical catalyst and heat to spur reactions that convert lignin into valuable chemical commodities. Lignin is a tough and highly complex molecule that gives the plant cell wall its rigid structure.
The study was published in the journal Green Chemistry. Mahdi Abu-Omar, Purdue’s R.B
Wetherill Professor of chemistry and Professor of chemical engineering and Associate Director of C3Bio, led the team. The process started with untreated chipped and milled
wood from sustainable poplar, eucalyptus or birch trees. A catalyst was added to start and speed the desired chemical reactions and can be recycled and reused. A solvent was added
to the mixture to help dissolve and loosen up the materials in a pressurized reactor and heated for several hours. The process broke up the lignin molecules and resulted in
lignin-free cellulose and a liquid stream that contained two additional chemical products. They also developed an additional process that uses another catalyst to convert the two phenol products into high-octane hydrocarbon fuel suitable for use as drop-in gasoline. The fuel produced has a research octane rating greater than 100. The research explored four promising lignin applications: BTX, phenol, carbon fiber and vanillin. The researchers found they can create carbon with a structure made up of several tiny tubes. These tubes are one thousand times smaller than an average human hair.