High octane unleaded aviation gasoline
View Patent ↗High octane unleaded aviation gasoline having low aromatics content and 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 of less than −58° C. is provided.
1. An unleaded aviation fuel composition having a MON of at least 99.6, sulfur content of less than 0.05 wt %, 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, comprising a blend comprising:
from about 5 vol. % to about 20 vol. % of toluene having a MON of at least 107;
from about 2 vol. % to about 10 vol. % of toluidine;
from about 35 vol. % to about 65 vol. % of at least one alkylate or alkyate 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 5 vol. % to about 20 vol. % of a diethyl carbonate with the proviso that the combined toluene and diethyl carbonate content is at least about 20 vol. %; 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 8% to 22 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 alcohols 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 having a freezing point of less than −58° C.
7. The unleaded aviation fuel composition of claim 4 wherein no other oxygenates than diethyl carbonate and fuel system icing inhibitor additives are present.
8. The unleaded aviation fuel composition of claim 1 wherein the final boiling point of at most 200° 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 combined toluene and diethyl carbonate content is at least 30 vol. %.
11. The unleaded aviation fuel composition of claim 1 having water reaction within +/−2 mL as defined in ASTM D1094.
12. The unleaded aviation fuel composition of claim 1 further comprising aniline.