Increasing octane rating as simple as adding xylene?

[Elite Engineer]

For a boost in octane rating (starting at 93), I read, adding xylene to gasoline (about 30% of the gas that you have). Is it this simple or is there more to it ?

 

 

 

 

~EE

 

[John Cuthber]

It is simple, but not cheap.

[Elite Engineer]

Question is in the title

 

~EE

[Enthalpy]

Why prefer xylene over toluene?

 

I also bought "mixed isoalkanes C9 to C11" as a solvent at a hobby market. I suspect it's the heavier fraction of the output of a refinery's alkylation unit. Then it would be very similar to avaiation gas, which has octane rating ~120.

[Enthalpy]

The octane rating relates very strongly with the autoignition temperature

http://www.engineeringtoolbox.com/fuels-ignition-temperatures-d_171.html

aromatics have a high autoignition temperature, branched alkanes too, linear alkanes a low one. I don't know for sure the detailed reason.

[swansont]

!

Moderator Note

"What "mechanism" makes adding xylene to gasoline increase its octane rating?" (title referred to in post 3) merged with existing thread on the subject

[GM11]

check your pipe work and such for solvent compatibility