AMHERST, Mass. – Chemical engineering researchers Wei Fan, Paul Dauenhauer and colleagues at the University of Massachusetts Amherst report this week that they’ve discovered a new chemical process to make p-xylene, an important ingredient of common plastics, at 90 percent yield from lignocellulosic biomass, the highest yield achieved to date. Details are in the current issue of Green Chemistry.

As Dauenhauer explains, the chemical industry currently produces p-xylene from more expensive petroleum, while the new process will make the same chemical from lower-cost, renewable biomass. He and colleagues call the process “ultraselective” because of its ability to achieve 90 percent selectivity for the desired product. “The biomass-derived p-xylene can be mixed with petroleum-based plastics, and consumers will not be able to tell the difference. But manufacturers and chemical companies will be able to operate more sustainably and at lower cost in the future because of this discovery,” he adds.

3D model of p-xylene molecule. Researchers have discovered a new chemical process to make p-xylene, an important ingredient of common plastics, at 90 percent yield from lignocellulosic biomass, the highest yield achieved to date. Image courtesy of Karlhahn, Wikimedia Commons

Consumers already know the plastics made from this new process by the triangular recycling label “#1” on plastic containers. Xylene chemicals are used to produce a plastic called PET (polyethylene terephthalate), which is currently used in many products including soda bottles, food packaging, synthetic fibers for clothing and even automotive parts, Dauenhauer says.

The UMass Amherst team’s discovery reveals the impact of nano-structured catalyst design on renewable chemical processes. Led by Fan, they examined a large number of nano-porous catalytic materials, including zeolites, investigating their capability for producing p-xylene. A specific material identified as ‘zeolite beta’ was found to be optimal. “We discovered that the performance of the biomass reaction was strongly affected by the nanostructure of the catalyst, which we were able to engineer and achieve 90 percent yield,” Fan says.

Besides Dauenhauer and Fan, the research team includes Chun-Chih Chang, Sara Green and C. Luke Williams, doctoral students in chemical engineering at UMass Amherst.

This discovery is part of a larger effort by the campus’s Catalysis Center for Energy Innovation to create breakthrough technologies for producing biofuels and chemicals from lignocellulosic biomass. The center is funded by the U.S. Department of Energy as part of the Energy Frontiers Research Center (EFRC) program, which involves more than 20 faculty members with complementary skills to collaborate on solving the world’s most pressing energy challenges.