How is propanol converted into propene

CO2 as a raw material: making electrosynthesis of alcohols more energy-efficient

A one-step process for the electrochemical production of methanol, ethanol, propanol and butanol from CO2 and develop water - this is the aim of »ElkaSyn - increasing the energy efficiency of electrocatalytic alcohol synthesis«. Fraunhofer UMSICHT (coordination), Siemens AG, Mitsubishi Hitachi Power Systems Europe GmbH, the Institute for Technical Chemistry at the University of Stuttgart and the chairs for Inorganic Chemistry I and for Process Engineering Transport Processes at the Ruhr University in Bochum are behind the research project.

Existing concepts for material CO2-Usage often provide for a two-step process. It all starts with an electrolysis process in which hydrogen is produced with the help of renewable electricity. A catalytic process step follows. The hydrogen is mixed with CO2 converted to the desired end product - for example alcohols. The disadvantages: On the one hand, the intermediate product hydrogen has to be stored; on the other hand, energy losses occur during electrolysis for hydrogen production.

Energy-efficient reduction of CO2 to alcohols

This is where the "ElkaSyn - increasing the energy efficiency of electrocatalytic alcohol synthesis" project comes in. The researchers want to develop processes with which the C1- to C4-Alcohols methanol, ethanol, propanol and butanol are produced in a one-step process directly using renewable energy, carbon dioxide and water. Such a one-step electrochemical reduction of CO2 In addition to alcohols, there is no need to store the intermediate product hydrogen or the system costs for a reactor in which hydrogen and CO2 to be implemented in the target products. The successful development of the one-stage process is expected to result in energy savings of up to 20 percent compared to a two-stage process.

On the way to such a single-stage reduction, the researchers rely on two different reactor concepts. You develop or examine system components for a high pressure and a normal pressure process. These include iron-nickel sulfides, copper-based compounds on oxidic and carbon carriers and porous gas diffusion electrodes in which gases are in contact with an electron-conducting, possibly catalyst-activated solid and an electrolysis solution and are converted.

On the meaning of methanol, ethanol, propanol and butanol

The end products methanol, ethanol, propanol and butanol are of great importance for various processes. The C1-Alcohol Methanol is - apart from its role as an energy carrier - one of the most important basic chemicals and is largely processed into formaldehyde, acetic acid, methyl tert-butyl ether, methyl methacrylate, methyl chloride and methyl amines. The C2- to C4-Alcohols Ethanol, propanol and butanol can be further processed into alkenes and dienes that are still extracted from petroleum today. Ethanol and propanol can be converted into ethene and propene - the starting materials for the plastics polyethylene and polypropylene. Butanol can be used to make butadiene - the raw material for synthetic rubber.