Ethyl tert-butyl ether

• Ethyl tertiary -butyl ether
• ETBE
• 2- ethoxy-2- methylpropanoic
• Tert- butyl ethyl ether

Colorless liquid

Liquid

0.74 g · cm -3

-94 ° C

73 ° C.

173 hPa ( 25 ° C)

Little in water ( 12 g · l-1 at 25 ° C)

1.375 (20 ° C)

Risk

Template: Infobox chemical / molecular formula search available

117 RON, MON 101

-19 ° C

Ethyl tert -butyl ether ( ETBE), according to IUPAC actually correct tert- butyl ethyl ether, is a chemical compound belonging to the group of ether. It consists of a tert- butyl group linked through an ether bond with an ethyl radical on the tertiary carbon atom of the Isobutyls. ETBE is a means for increasing the octane number in gasoline.

Production

They are prepared by acid-catalyzed addition of ethanol to the double bond of the isobutene:

Properties

ETBE is a colorless liquid which is not miscible with water.

Use

ETBE is to methyl tert- butyl ether (MTBE ) to improve the antiknock properties added in analogy to the gasoline fuel (up to 15 vol - %). MTBE is produced from fossil fuels. ETBE other hand, can be produced for example from fossil isobutene and ethanol from renewable resources ( bio-ethanol ).

In the EU has to be made in accordance with the Renewable Energy Directive ( EC) 2020 of using 10 % renewable energy in transport. A large part of this objective is to be achieved through the use of biofuels. In Germany, a minimum proportion of biofuels from 8% (by ​​energy ) required by the total fuel market by the Biofuel Quota Act ( BioKraftQuG ) by 2015. This was reduced by the Act amending the promotion of biofuels again, such that a biofuel quota of 6.25 % by the year 2014. Through the stoichiometrically calculated bioethanol content in "Bio -ETBE " can this be counted to 47% biofuel blend. ETBE is more expensive than bioethanol. The incorporation into motor gasoline is therefore only if, for technical reasons ( eg lack of admixture technology) no Bioethanol can be used, or if higher petrol variants are to be produced ( octane number of ETBE is higher than that of ethanol).

As part of the so-called MTBE bans ( see MTBE) and the addition of ETBE into gasoline in several U.S. states is prohibited.