High octane unleaded aviation gasoline

1. An unleaded aviation fuel composition having a MON of at least 99.6, sulfur content of less than 0.05 wt %, CHN content of at least 98 wt %, less than 2 wt % of oxygen content, an adjusted heat of combustion of at least 43.5 MJ/kg, a vapor pressure in the range of 38 to 49 kPa, comprising a blend comprising:

from about 35 vol. % to about 55 vol. % of toluene having a MON of at least 107;

from about 2 vol. % to about 10 vol. % of aniline;

from about 15 vol. % to about 30 vol. % of at least one alkylate or alkylate blend having an initial boiling range of from about 32° C. to about 60° C. and a final boiling range of from about 105° C. to about 140° C., having T40 of less than 99° C., T50 of less than 100° C., T90 of less than 110° C., the alkylate or alkylate blend comprising isoparaffins from 4 to 9 carbon atoms, about 3-20 vol. % of C5 isoparaffins, about 3-15 vol. % of C7 isoparaffins, and about 60-90 vol. % of C8 isoparaffins, based on the alkylate or alkylate blend, and less than 1 vol. % of C10+, based on the alkylate or alkylate blend;

from about 4 vol. % to less than 10 vol. % of a branched chain alcohol having 8 carbon atoms provided that the branched chain does not include t-butyl groups; and

at least 8 vol. % of isopentane in an amount sufficient to reach a vapor pressure in the range of 38 to 49 kPa;

wherein the fuel composition contains less than 1 vol. % of C8 aromatics.

2. The unleaded aviation fuel composition of claim 1 wherein the total isopentane content in the blend of 10 vol. % to 26 vol. %.

3. The unleaded aviation fuel composition of claim 1 having a potential gum of less than 6 mg/100 mL.

4. The unleaded aviation fuel composition of claim 1 wherein less than 0.2 vol. % of ethers are present.

5. The unleaded aviation fuel composition of claim 2 further comprising an aviation fuel additive.

6. The unleaded aviation fuel composition of claim 1 having a freezing point of less than −58° C.

7. The unleaded aviation fuel composition of claim 1 wherein no straight chain alcohol and no noncyclic ether are present.

8. The unleaded aviation fuel composition of claim 1 having a final boiling point of less than 190° C.

9. The unleaded aviation fuel composition of claim 1 wherein the alkylate or alkylate blend have a C10+ content of less than 0.1 vol. % based on the alkylate or alkylate blend.

10. The unleaded aviation fuel composition of claim 1 wherein the branched chain alcohol is 2-ethyl hexanol.

11. The unleaded aviation fuel composition of claim 8 having the final boiling point of at most 180° C.

12. The unleaded aviation fuel composition of claim 1 wherein T10 is at most 75° C.