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Bazzi receives second U.S. patent for Texas A&M at Qatar for novel catalyst

Published Jun 29, 2016

Dr. Hassan S. Bazzi, professor of chemistry and assistant dean for research at Texas A&M University at Qatar, has received a U.S. patent for a catalyst that makes a widely used type of chemical reaction more efficient.

The patent is the second patent issued that involves Texas A&M at Qatar faculty. Bazzi developed the catalyst in collaboration with Dr. Dave Bergbreiter, professor in the Department of Chemistry at Texas A&M’s main campus in College Station, Texas, USA.

Bazzi and Bergbreiter began working together in summer 2006 on the catalyst, a molecule that kickstarts a chemical reaction. In this case, that chemical reaction was metathesis, which is a type of catalysis used in chemistry to make small molecules or chains of molecules called polymers. Metathesis is an important chemical reaction involving carbon-carbon double bonds that can be used to make cyclic compounds, which are very important in pharmaceuticals and in building polymers, Bazzi said.

“The importance of metathesis is that it builds on building double bonds,” he said. “It’s like Legos, you’re having building blocks coming together. Once you form the polymers, the polymers can have several applications and there are applications in industry, such as in coatings, in bulletproof windows, even water-soluble polymers. The field is huge.”

Metathesis has garnered so much attention in the past two decades after three people — Robert H. Grubbs from Caltech (who is also an adjunct professor of chemistry at Texas A&M at Qatar), Richard Schrock from MIT and Yves Chauvin from France — were awarded the Nobel Prize in Chemistry in 2005 for making metathesis into one of organic chemistry's most important reactions.

The problem with metathesis, though, is that a small amount of the metal-based catalyst remains in the end product. In the pharmaceutical industry, for example, you don’t want patients ingesting the metal left in the drug. In other applications, such as materials, the metal in the polymer may color the material or alter its properties. Bazzi said he and Bergbreiter decided to try to modify the ruthenium-based metathesis catalyst to make the whole catalytic operation more efficient and easier to remove the metal from the final product.

“One of the drawbacks of this reaction is the amount of metal that is left in the product,” Bazzi said. “Our example was the first to use a nonpolar tag — a polymer called polyisobutylene — that we attach to the catalyst and then at the end of the reaction we use it as a handle to pull the metal out. And that reduces the metal leaching, or the metal remaining in the product, quite extensively.”