Researchers at Northwestern University in the US have successfully produced methanol from methane gas using a lightning plasma in glass tubes. The achievement demonstrates that the potential for carrying out energy-intensive reactions can be realized quickly and easily in plasma-generating bubble reactors. 

Methanol is a chemical with diverse uses and can be burned cleanly, producing no smoke. It can be used in vehicles and marine vessels, as well as cooking stoves, and finds wider applications in industry to produce certain plastics and acids, as well as an industrial solvent.

Although widely used, methanol production is an energy-intensive process that requires temperatures over 1,400 Fahrenheit and 200-300 times atmospheric pressure to form methanol molecules. This makes methanol use unsustainable in the long run, prompting scientists to seek simpler, more energy-efficient ways to synthesize it. 

Lightning in a bottle

To overcome the high-temperature requirement for methanol synthesis, Northwestern researchers used electricity to generate a plasma state of matter inside a water-filled reactor. Glass tubes coated with copper-oxide catalysts feed the methane gas needed for the reaction. 

When high-voltage pulses are applied within the reactor, the gas is also converted to plasma, producing highly reactive fragments that quickly form methanol. Conventional methanol synthesis reactions also face another hurdle is methanol degradation, where newly formed methanol rapidly degrades into carbon dioxide. 

In this setup, the methanol is immediately absorbed by the surrounding water, thereby freezing the reaction and avoiding the degradation step. To further enhance the reaction, the researchers also added argon, which stabilized it and prevented the formation of unwanted products. 

Greenhouse gases to useful chemical

Eliminating the need for high temperatures and pressures helps reduce the cost of methanol production. Moreover, the new approach is a single-step reaction, which is much more streamlined and has a smaller environmental impact. 

“We also ended up with ethylene, which is a precursor to plastic production, and hydrogen gas, which is an important commodity chemical and a zero-carbon fuel in its own right,” said Dayne Swearer, assistant professor in Chemistry at Northwestern University, who co-led the research. 

“So, we took methane, which is a very abundant gas, and turned it into methanol along with ethylene, hydrogen and a bit of propane. These are all intrinsically more valuable products.”

The researchers acknowledge that their setup is still at a laboratory scale, but if successfully scaled, it could help turn methane-leaking sites into locations where methanol can be produced. The team is now focused on optimizing their approach and on recovering methanol from water and separating it into a purified product. 

“Right now, the way to deal with leaked methane is to light it on fire to turn it into carbon dioxide, which warms the climate less than methane but is still clearly a problem,” explained Swearer in a press release.

“Instead, we could take a smaller-scale reactor to the place that’s leaking methane and turn it into a transportable liquid fuel.”

The research findings were published in the Journal of the American Chemical Society.