Methanol Production – a Key Intermediate in the Electrochemical Interconversion of Organics to Chemicals and Fuels
Authors: Omasta Travis J , Peng Xiong , Mustain William E 
Published: February 2020

Methanol is the world’s 5th largest commodity chemical by volume. It can be used to synthesize numerous products, and has been touted as an important energy carrier of the future. It has a high energy density and is a liquid at atmospheric conditions, which make it ideal for stable transportation and storage that is compatible with existing infrastructure, which is quite the opposite of methane or even hydrogen gas.1 The production of methanol and its interconversion is typically achieved through the steam reforming of methane to syngas – this is a very energy intensive pathway, along with many intermediate reaction steps that result in an inelegant and energetically circuitous process. Therefore, a low temperature, low energy process is desired to produce methanol from methane. Electrochemical processes are ideal because they allow for control of the catalyst surface free energy directly, thus methanol production may be realized in a single reactor.2 Continuing to use methane for this conversion makes sense from an economic perspective because of the very low cost of natural gas today.

However, the low cost of natural gas also ensures that carbon sources will be used for electricity generation for the foreseeable future – releasing carbon dioxide. CO2 is believed to be the largest contributor to global climate change, with more than 35 gigatons per year (and climbing) being emitted into the atmosphere. However, the global demand to reduce carbon dioxide emissions means that soon we will need to capture this power plant derived CO2, which could flood the market with a new chemical feedstock. Another interesting source for emerging chemical feedstocks, such as acetate (acetic acid) is biomass fermentation.

As we move forward in the 21st century, it is becoming clear that in the very near term, we will have access to a diversity of feedstocks and it is very important to find low energy pathways convert between several small hydrocarbon oxygenates that have market value including: methanol, ethanol, formate, acetate, and carbon monoxide have industry and commercial value. Since electrochemistry can play a critical role in this paradigm, a deeper understanding of an electrochemical pathway from methane to methanol and beyond is desired, from a deeper fundamental understanding to a larger commercial application.

In this poster, we will show recent experimental work in our group regarding the transformation of methane, CO2 and acetate to methanol. We will show the utility of catalysts such as copper, silver, gold, and palladium/copper, and others, to develop a link and fundamental pathway between oxygenates. We will also discuss possibilities other than methanol, and to start to build an electrochemical map from methane to carbon dioxide and back, stopping at all the compounds in between.

References

1. G. A. Olah, A. Goeppert and S. K. Surya-Prakash, Beyond oil and gas: the methanol economy, Wiley-VCH (2009).

2. N. Spinner and W. E. Mustain, J. Electrochem. Soc.,
159, 12 (2012).