By Bruce Hall

In a paper in New Scientist, Rachel Nowak describes a new process converts carbon dioxide into methanol, without the need for extreme temperatures and pressures.

Just one problem:

Methanol combustion is: 2CH3OH + 3O2 = 2CO2 + 4H2O + heat

Are we missing something here?

Here are some excerpts from the paper:

CONVERTING a greenhouse gas into a clean-burning fuel offers two benefits for the price of one. That’s the thinking behind a novel process for converting carbon dioxide into methanol at room temperature, developed by a team at the Institute of Bioengineering and Nanotechnology in Singapore (Angewandte Chemie International Edition, DOI: 10.1002/anie.200806058).

Molecules of CO2 are very stable, so processes that convert the gas to methanol normally require high temperatures and pressure. They also use catalysts containing toxic metal ions. “Our catalyst isn’t toxic, and the reaction happens rapidly at room temperature,” says team leader Jackie Ying.

The catalyst used by Ying’s team is a type of chemical called an N-heterocyclic carbene (NHC). The mechanism by which the NHC speeds up the conversion is uncertain, but it appears to change the shape of the CO2 molecule, “activating” it in a way that makes it easier for hydrogen to bond with its carbon atom, says team member Yugen Zhang.

The catalyst may also help to release hydrogen from hydrosilane molecules, which are the source of hydrogen in the new process. Hydrosilane is an expensive chemical usually used to make computer chips, so the team wants to find a cheaper source.

“Potentially, it’s a means for taking carbon dioxide out of the air and making it into something useful,” says Dongke Zhang, director of the Centre for Petroleum, Fuels and Energy at the University of Western Australia in Perth. As well as being a fuel, methanol can be used as a feedstock for the chemical industry. Zhang’s team is developing a technique for converting CO2 into methanol using high-frequency electromagnetic fields or plasmas to activate the gas. See Bruce’s post here.

In other words, for those without knowledge of chemistry, when you burn methanol, the two principle byproducts aside from the desired heat are water vapor and carbon dioxide, both greenhouse gases. So one removes carbon dioxide to produce methane and then burns methane which releases carbon dioxide. Along the way, other chemicals and energy was used to produce the methane which is readily available already from natural sources.