University scientists produce isoprene from sustainable resources

MINNEAPOLIS—Obtaining isoprene from sustainable sources has long been a goal for tire manufacturers.

Now, a team of researchers led by the University of Minnesota says it has accomplished that.

According to the university, the researchers have invented a new technology to produce isoprene from trees, grasses and corn.

Tires produced using isoprene from biomass would be identical to existing tires, with the same chemical composition, color and performance, the university said.

The study describing the research that led to this breakthrough has been published in ACS Catalysis, the American Chemical Society's journal on chemical and catalysis sciences, according to the university.

Paul Dauenhauer, an associate professor of chemical engineering and materials science at the University of Minnesota, led the project with the help of researchers from the Center for Sustainable Polymers, a group funded by the National Science Foundation and headquartered at the university.

Traditionally, isoprene is produced by "cracking," a process of breaking apart petroleum molecules in a method similar to producing gasoline, according to the university.

The isoprene is separated out of hundreds of products and purified, the university said. In the final step, the isoprene reacts with itself into long chains to make a solid polymer that is the major component of tires, it said.

Tire makers have tried for the past decade to make biomass-derived isoprene, concentrating mainly on fermentation technology, according to the university. However, it has proven difficult to generate renewable isoprene from microbes, it said.

The University of Minnesota process begins with sugars derived from biomass, the university said. It is a three-step process that combines microbial biological fermentation with conventional catalytic refining, it said.

The first step of the process is fermenting the sugars derived from biomass into an intermediate called itaconic acid, the university said. The second step consists of reacting itaconic acid with hydrogen into a chemical called methyl-THF, it said.

In the third step, methyl-THF is dehydrated into isoprene, using a catalyst called P-SPP (Phosphorus Self-Pillared Pentasil) that was discovered recently at the University of Minnesota.

Using P-SPP, the research team achieved a catalytic efficiency as high as 90 percent, with most of the catalytic product being isoprene, the university said.

"The discovery of a highly efficient route to renewable rubber from biomass is just the first step towards commercialization," Dauenhauer said. "Fundamental research on this process technology will continue."

In the next phase of study, the researchers will engineer the process technology for scale-up to commercial size, Dauenhauer said.

Through its Office of Technology Commercialization, the University of Minnesota has applied for a patent on the isoprene production technology and plans to license the process to companies interested in commercializing it, according to Larry Micek, technology licensing officer at the Office of Technology Commercialization.