Bioethanol (alcohol)

Bioethanol is an alcohol produced from biomass that is primarily used as a biofuel. It is produced through alcoholic fermentation and is often blended with petrol. The chemical structure of bioethanol corresponds to that of synthetic ethanol.

Definition of bioethanol
Bioethanol is an alcohol produced by the fermentation of sugary or starchy plants and cellulosic raw materials. It is mainly used in fuels and has the same chemical properties as synthetically produced ethanol.

Background / origin
Bioethanol is produced by alcoholic fermentation, whereby microorganisms convert sugar and other carbohydrates into alcohol. Plants such as sugar beet and various types of grain are the most common raw materials for production in Germany. Cellulose-containing materials, in particular lignocellulose, can also serve as a starting material, but require biochemical pre-processing to break down sugar.

The entire fermentation process ends when the maximum possible alcohol concentration has been reached or the biomass has been used up. This is followed by multiple distillation to separate the ethanol from the water and ensure a purity of between 99.5 and 99.9% by volume. This purity is crucial to ensure that bioethanol remains stable in gasoline blends.

Properties
Bioethanol has the same chemical structure as synthetic ethanol, which is obtained from fossil fuels. It has the following physical characteristics:

- Composition: Bioethanol is produced from a variety of organic raw materials, primarily from plants containing sugar and starch as well as cellulose.
- Physical characteristics: It is a clear, colorless and easily vaporizable liquid.
- Quality differences: The main difference in quality lies in the purity of the ethanol. Higher purity grades are necessary for use in gasoline.
- Chemical characteristics: Bioethanol can be used in various blending ratios with gasoline (such as E5 and E10).

Application and importance in the market
Bioethanol is used worldwide as a biofuel and can be found in the fuel blends E5 and E10, among others. In Germany, up to 10% ethanol by volume may be blended with petrol in accordance with DIN EN 228. Around 90% of vehicles with gasoline engines can run on E10. The previous tax exemption for the bioethanol content in Germany ran until the end of 2015.

Bioethanol also serves as a base material for the production of the petrol additive ethyl tertiary butyl ether (ETBE). This additive improves the octane rating and reduces the energy-intensive production of petrol components. ETBE can be added up to 22% by volume.

Differentiation from similar terms
- Ethanol: The term includes both bioethanol and synthetic ethanol. Both types are chemically identical, but are produced differently.
- E5/E10: These terms refer to petrol with a certain proportion of bioethanol, whereby E5 contains a proportion of up to 5% by volume and E10 up to 10% by volume.
- E85: A higher proportion of bioethanol, which was widely used in some countries until the end of 2015, but is no longer offered as a fuel in Germany.

Summary
Bioethanol is a biogenic alcohol obtained from various plant-based raw materials, usually through alcoholic fermentation. It is primarily used as a biofuel in petrol blends and is widely accepted in vehicles with petrol engines in Germany. The additive ETBE, which is synthesized from bioethanol, improves the properties of petrol. With the change in taxation, E85 lost its market position and is no longer available in Germany.