UC Riverside chemists have come up with a novel way to add hydrogen to natural oils to prolong the shelf life of foods, while minimizing the production of trans fats that may have adverse health effects like increased bad cholesterol levels and coronary heart diseases.
In scientific parlance, the term hydrogenation is used to describe the addition of hydrogen to natural oils.
The researchers have revealed that they have basically designed a catalyst, a substance that accelerates a chemical reaction, which allows hydrogenated oils to be made while minimizing the production of trans fats.
Lead researcher Francisco Zaera, a professor of Chemistry, has revealed that the team used a common catalyst called platinum for these processes in their experiment.
The researcher said that the team controlled the shape of the platinum particles, which enabled them to make the catalyst more selective, that is, become capable of selecting a specific pathway from among many possible chemical reactions.
They said that in their case, selectivity referred to the production of partially hydrogenated fats without the making of trans fats.
Zaera's team found that the platinum catalyst performed most selectively when its particles assumed tetrahedral shapes, with the atoms arranged in a hexagonal honeycomb lattice.
Particles with these shapes allow for the preservation of the harmless cis configuration in the hydrogenated fats, and other lattices found by the researchers favour the production of trans fats.
The researchers call the platinum catalysts used by them heterogeneous because they exist in a different phase (solid) than the reactants (liquid or gas).
The research by Zaera and his colleagues is a breakthrough because it shows for the first time that it is possible to achieve selectivity with heterogeneous catalysts like platinum by controlling the structure of their surfaces.
"The more control we can exert on how we prepare catalysts, the more we can control the catalytic selectivity of a particular chemical process. Our work shows that it is possible to make heterogeneous catalysts that afford us more control on selectivity. This opens the door, we hope, for chemists to think about achieving selectivity for other reactions via the design of specific heterogeneous catalysts with specific shapes," Zaera said
He revealed that heterogeneous catalysts tended to be more practical in terms of manipulation, but were harder to control.
"Our paper shows that, thanks to new advances in nanoscience, sophisticated and highly selective heterogeneous catalysts can be made by controlling their structures. In this sense, our paper changes the paradigm of heterogeneous catalysis. These catalysts can now compete more closely with homogeneous catalysts, which industry traditionally uses for reactions that require high selectivity such as those involved in the manufacture of medicines or other fine chemicals," he said.
Zaera's lab next plans to find other reactions where selectivity is needed, and to improve on the synthetic techniques used to make selective catalysts.