Bioethanol 2.0

Synthesis of higher alcohols based on bioethanol for completely bio-based plasticizers

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Bio-based plasticizers

Plastics become flexible or malleable due to plasticizers. This makes them easier to work with or gives them specific usage characteristics.

© Fraunhofer UMSICHT

High-quality alcohols

Reactor for the synthesis of high-quality alcohols from bioethanol.

Project aims

In the Bioethanol 2.0 project, higher alcohols are produced from bio-based short-chain alcohols. The aim is to esterify the higher alcohols with citric and succinic acid in order to produce new, non-hazardous plasticizers that are independent of fossil raw materials. In this way, the bio-based proportion of plastics is to be increased over the long term while improving the performance of the materials at the same time.

Benefits

Demand for products made from bio-based raw materials is rising – especially where consumers come into direct contact with the products. Higher alcohols are an important raw material for the production of plasticizers used in plastics production. In the Bioethanol 2.0 project, a process was developed that enables the value creation of higher alcohols from bio-based ethanol and, in a next step, the production of bio-based plasticizers. For example, bioethanol, which has been used almost exclusively as a fuel until now, is used to produce high-quality material products.

Sustainable and economical synthesis route

Bioethanol offers a harmless alternative to conventional raw materials such as imported palm kernel oil and coconut oil, which have so far been used as raw materials for the production of bio-based higher alcohols. By esterifying the higher alcohols with citric and succinic acid, biologically harmless plasticizers can finally be produced. The fossil-based or non-sustainably produced alcohols based on vegetable oil are thus replaced by starting materials that are globally available and can be produced sustainably. In addition to the sustainable aspect, the process also offers economic advantages: At around 450 euros per tonne[K1] , ethanol is comparatively cheap. Plasticizers, on the other hand, cost between 1500 and 2500 euros per tonne. If the higher alcohols are produced bio-based from ethanol, and plasticizers are synthesized from them, the value of ethanol can be increased almost fivefold. The developed process allows for this leap in value creation.

Result

In the Bioethanol 2.0 project, a synthesis route for higher alcohols based on bioethanol was developed. In the process, ethanol is condensed into butanol and other longer-chain alcohols (such as 2-ethyl-hexanol). The basis for bio-based ethanol is sugar, which is fermented. In Europe, this comes mainly from grain or sugar beet and is, therefore, one of the renewable raw materials. In the long term, ethanol can also be produced from residues such as straw or syngas. Ethanol is not the only possible starting material for higher-grade alcohols: The project was able to show that other alcohols produced through fermentation such as butanol, isopropanol or acetone can also be used. The first syntheses for plasticizers produced from these alcohols were carried out as part of Bioethanol 2.0. Bio-based plasticizers were thus produced sustainably and cost-effectively for the first time.

Funding
Duration: July 2012 to July 2015
Funding code: 22028311
Website: www.bmel.de