The “Holy Grail reaction” in organic chemistry was recently reached by a team at the Institute of Basic Science in Daejeon, South Korea.
The team, headed by Dr. Mu-Hyun Baik, managed to catalyze certain reactions with methane, the most basic hydrocarbon.
Through the in silico, or computer-assisted, prediction and modeling of reaction conditions, in adjunct to high-throughput lab screening, they managed to achieve the borylation of methane at yields as high as 52 percent.
Hydrocarbons, chemical compounds consisting only of hydrogen and carbon atoms, are the most fundamental chemical building blocks in organic chemistry. The ability to manipulate, synthesize and break them down is key for deriving most other carbon-containing compounds. Many important industrial and medical products, such as plastics, medicines and fertilizers, are produced from hydrocarbons.
Petrofuels, which are some of the most well-known hydrocarbons, are still a major driver of human industry.
Methane, the simplest single-bonded hydrocarbon, is denoted by the chemical formula CH4. As is sometimes apparent outside of laboratories, methane is readily combustible at high temperatures. For the purpose of chemical synthesis, however, the conditions required for the controlled use of methane to create other products are too gentle to break its tough carbon-hydrogen bonds. To make matters more difficult, methane has low solubility and is highly nonpolar due to its chemical properties. All of these factors, in combination, have made the use of methane extremely cumbersome and difficult, until the discovery of the specific catalysts and reaction conditions used by Baik’s team.
In this experiment, the team was divided into two halves. One group used in silico prediction, while the other experimentally tested the varying permutations of ligands and metal catalysts that were offered by the computer models. The reaction that they optimized was the borylation of methane, or the conversion of the methane into a more easily transported and usable fuel by swapping its hydrogen with boron. They achieved the greatest success under conditions of 150 degrees Celsius and 3,500 kilopascals of pressure with iridium as the metal catalyst. While the team managed to achieve this reaction at such high yields and validated this combined computational-experimental approach, Baik noted in the paper that there is still work to be done. Iridium, despite its discovered effectiveness in methane catalysis, is a rare and expensive metal. Cobalt was proposed as a possible replacement, due to its similarity in chemistry and its greater commonality.
With the falling world reserves of petroleum, and the ramifications of “petropolitics,” one of the keys to fueling independence for nations that do not have oil reserves may be the easier manipulation of methane. Methane is relatively plentiful with available sources spread across the world. Though fracking and the extraction of these methane reserves is controversial, the ability to use existing methane supplies through the discovery of favorable reaction conditions like these might increase the use of methane globally.
