Re: Organic chem -- or was it "ethanol"

[loescher@tamu.edu (Mitch Loescher)]

>> Ethanol statement - makes it burn less efficient, but producing more 
>> power. Isn't this a contradiction in terms? It has been my impression
>> that it is sold in an effort to reduce polution.
>
>It's been my impression that it's sold in an effort to subsidize corn 
>growers...

Ethanol raises the octane slightly, but it also has a relatively high vapor
pressure which results in emissions from the tank (on hot days).  It also
has a high heat of vaporization which means it can affect cold start
performance.  MTBE also raises the octane, but has lower VP, and lower heat
of vaporization. 

Ethanol produced for fuel is not subject to federal taxes.  It is not
subsidized per-se, but the tax exemption may be considered a subsidy.
Without this, ethanol is overwhelmingly uneconomical.  All other fuels sold
in the US are taxed.  The exemption is due to the farm lobby and the
"green/renewable energy" lobby.

Refiners want to try to use ETBE (ethyl t-butyl ether), because it has
similar properties to MTBE (methyl t-butyl ether) so they could use bio/corn
produced ethanol in its manufacture, but the corn lobby is fighting giving
this ETBE the exemption, because it feels it would lose ethanol sales.
Politics.

 - Mitch Loscher
   '87 5000S Quattro
   Chemical Engineering Department
   Texas A&M