Scientist Javier Grajeda of Eastman and chemist Alex Miller of the University of North Carolina-Chapel Hill are spearheading a cooperative academic-industry team to find more environmentally friendly ways to develop the fundamental building blocks of the chemical industry.
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Compounds such as methanol and methyl esters are currently transformed in the chemical industry into acetic acid or acetic anhydrides, which are then incorporated into plastics, fabrics, drugs, and other products. Carbonylation processes, in which a carbon monoxide unit is added to a substance, produce millions of tons of these chemical building blocks.
However, these reactions have typically relied on expensive and scarce precious metal catalysts such as rhodium and iridium to speed the reaction. The team's novel reaction technique provides a potential alternative.
A new study published in Science on November 17th, 2023, shows that nickel, when combined with organic imidazole derivatives, is a good compound system for carbonylation processes. Nickel is a significantly more cost-effective, abundant, and ecologically friendly metal source than rhodium.
Previous studies of nickel carbonylation catalysis, which used phosphine ligands, found that even when significant amounts of catalyst and promoters were applied, the rate of product formation was slow.
With strong activity even at low loadings of nickel, ligand, and additives, the combination of nickel and organic imidazole derivatives proved to be an exceptional catalyst system. The catalyst system exhibits air tolerance and can be refueled with carbon monoxide without experiencing significant reductions in activity.
Nickel is far less expensive than rhodium, which is another important advantage. For reference, one troy ounce of rhodium can cost the same as one metric ton of nickel. More research and optimization are possible because of the rates of the new nickel system, which can be compared to the most advanced precious metal catalysts being utilized in industry today.
Funding was provided for the research through an ongoing collaboration between UNC-Chapel Hill and Eastman, which was formed in 2013. With 38 sponsored research projects totaling over $7 million and covering five departments at Carolina, Eastman has financed them over the last ten years.
Journal Reference
Yoo, C., et. al. (2023) Nickel-catalyzed ester carbonylation promoted by imidazole-derived carbenes and salts. Science. doi:10.1126/science.ade3179
Source: https://www.unc.edu/