The chemical industry is intensively researching ways to replace crude oil with renewable alternatives. Of particular interest here is the approach of using the greenhouse gas carbon dioxide, which is produced as exhaust gas in many processes. In this way, the climate could be protected at the same time as carbon could be fed into a sustainable circular economy. The newly launched "ElkaSyn" project is now investigating two approaches to making such processes more efficient and thus more economical.

Reducing processes to one step

As a rule, hydrogen is required to react with carbon dioxide to form higher-value compounds. Hydrogen is produced by electrolysis, which is ideally powered by electricity from renewable sources. Only in a second step does the catalysis take place to produce starting materials, for example for the production of plastics. This two-stage process not only requires intermediate storage of the hydrogen, but also involves energy losses. Several German research institutions and technology groups now want to jointly develop a single-stage process and thus save about one fifth of the energy previously required. The project will be funded by the Federal Ministry of Economics until 2022.

Two approaches in development

The researchers are investigating two possible concepts for a high-pressure and a normal-pressure process. The reactor components developed for this purpose include iron-nickel sulfides, copper-based compounds on oxidic carriers and carbon carriers as well as porous gas diffusion electrodes in which gases are in contact and converted with an electron-conducting solid and an electrolysis solution.

Creating an economical alternative to crude oil

The result are the alcohols methanol, ethanol, propanol and butanol. Methanol is an important basic chemical which is processed into formaldehyde, acetic acid, methyl tert-butyl ether, methyl methacrylate, methyl chloride and methyl amines. Ethanol, propanol and butanol are the starting materials for alkenes and dienes, which are used, for example, in the production of polyethylene, polypropylene and synthetic rubber. At present, these products are primarily produced from petroleum-based raw materials, as this has previously been more economical.

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