SC - OT Octane was brewing

[Gedney, Jeff]

hmmm....
this is dredging up old science courses I thought long buried, but...

I thought "Octane" was a reference to the "Carbon Ring" structure of the
petrol.
As I understood it, an Octane ring has eight carbon atoms and is
"chained" together in strings of varying numbers of rings. So a "93
octane" fuel has chains of octane rings, 93 rings long in each molecule.
the more rings, the more carbon atoms available for combustion per
molecule. Hence more power and sustained combustion at high compression,
resulting in less "knocking" ( predetonation ) in a "piston" engine.
The process of refining gasoline is done by "crack" refining, this uses
a catalyst to break ("crack") the longer octane chains of the unrefined
petroleum at specified points, and selectively distill off the various
fuels produced in a "stepped" distillation process.

A "hexane" ring has six atoms. I think that most "natural gas" fuel is
hexane based.
I understand that there are pentanes and heptanes, as well. 


Brandu


> ----------
> From: 	margali[SMTP:margali at 99main.com]
> Reply To: 	sca-cooks at Ansteorra.ORG
> Sent: 	Wednesday, January 07, 1998 10:27 AM
> To: 	sca-cooks at Ansteorra.ORG
> Subject: 	Re: SC - OT Octane was brewing
> 
> > I'll pobablyget castigated for continuing this, but my all three of
> my
> >
> > Mustangs are screaming bloody murder right about now:-)
> > Actually, octane is a measure of a fuel's resistance to premature
> > detonation.
> >
> > 2MACH4U, Puck
> 
> Actually, it is a number indicating the degree of knocking of a fuel
> mixture under standard test conditions. pure normal heptane is
> arbitrarily assigned a rating of 0 and isooctane is assigned 100,
> making
> the amount of knocking in the test engine of a liquid rated at 80 is
> the
> equivalent of 80 parts heptane, 20 parts isooctane. to get octane
> results of over 100 require the addition of lead alkyl
> products[tetraethyl or tetramethyl lead iirc]. there is a chemical
> known
> as n-octane, c8h18 or ch3[ch2]6ch3 used as a solvent and in the iso
> form
> for callibrating testing aparatus.
> margali
> ex car nut, x chem factory worker, civillian nuke, and lover of
> useless
> triviata
> 
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