High octane unleaded aviation gasoline
View Patent ↗High octane unleaded aviation fuel compositions having a CHN content of at least 97.2 wt %, less than 2.8 wt % of oxygen content, a T10 of at most 75° C., T40 of at least 75° C., a T50 of at most 105° C., a T90 of at most 135° C., a final boiling point of less than 210° C., an adjusted heat of combustion of at least 43.5 MJ/kg, a vapor pressure in the range of 38 to 49 kPa is provided.
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 97.2 wt %, less than 2.8 wt % of oxygen content, a T10 of at most 75° C., T40 of at least 75° C., a T50 of at most 105° C., a T90 of at most 135° C., a final boiling point of less than 210° C., an adjusted heat of combustion of at least 43.5 MJ/kg, a vapor pressure in the range of 38 to 49 kPa, and a freezing point is less than −58° C comprising a blend comprising:
(a) from about 15 vol. % to about 40 vol. % of toluene having a MON of at least 107;
(b) from about 2 vol. % to about 10 vol. % of toluidine;
(c) from about 30 vol. % to about 55 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;
(d) from about 4 vol. % to about 10 vol. % of a branched alkyl acetate having branched chain alkyl group having 4 to 8 carbon atoms; and
(e) 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 14% 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 alkanols and 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 wherein no straight chain alcohol and no noncyclic ether are present.
7. The unleaded aviation fuel composition of claim 1 wherein the final boiling point of at most 200° C.
8. 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.
9. The unleaded aviation fuel composition of claim 1 further comprising aniline.
10. The unleaded aviation fuel composition of claim 1 having water reaction within +/−2 mL as defined in ASTM D1094.
11. The unleaded aviation fuel composition of claim 1 wherein the branched alkyl acetate is selected from the group consisting of t-butyl acetate, iso-butyl acetate, ethylhexylacetate, iso-amyl acetate, t-butyl amyl acetate, and mixtures thereof.