Ethyl Tertiary Butyl Ether (ETBE) is produced from ethanol and isobutylene in a catalytic reaction. Blending with ETBE, improves the combustion characteristics of petrol, and ETBE is also more compatible with pipelines and engines than ethanol.
ETBE is produced from bioethanol (Bio-ETBE). Isobutylene is currently derived from fossil sources from either refining or from natural gas. ETBE provides improvements in air quality when blended into conventional gasoline. The EU maximum blending level specification for ETBE is 22% in E10 gasoline and 17.24% mass in E5 (equivalent to 2.7% mass of oxygen).
Bio-ETBE is extensively used in the EU in conventional vehicles and fuel distribution systems. This requires minimal investment in distribution system infrastructure. Bio-ETBE currently accounts for the majority of bioethanol destined for the EU gasoline market.
In February 2017, GlobalBioenergies has announced the production of ETBE purely from renewable resources, at its facilities in France. This breakthrough represents a new opportunity for increasing the proportion of biofuels in gasoline. The innovation consists of using this same process to combine renewable ethanol with renewable isobutene obtained using Global Bioenergies' technology. This purely renewable ETBE holds the potential for incorporating 2.7 times more renewable energy in gasoline than with traditional biofuels. It will also help to cut greenhouse gas emissions even further.
Tert-Amyl Ethyl Ether (TAEE) is also be derived from ethanol. Bioethers are also produced from biomethanol (e.g. MTBE, TAME).
Further information on ETBE and bioethers is available from the European Fuel Oxygenates Association