Unleaded aviation gasoline

Abstract: An unleaded aviation gasoline composition which comprises a blend of hydrocarbons and at least one cyclopentadienyl manganese tricarbonyl compound dissolved therein in an amount such that the composition has a minimum knock value lean rating octane number of 100 as determined by ASTM Test Method D2700 and wherein Motor Method octane ratings are converted to aviation ratings in the manner described in ASTM Specification D910-90, the composition being further characterized by having: a) a distillation temperature by ASTM Test Method D86 of 10% evaporated, 167°F maximum temperature; 40% evaporated, 167°F maximum temperature; 90% evaporated, 275°F maximum temperature; and a final boiling point of 338°F maximum temperature; the sum of the 10 and 50% evaporated temperatures being 307°F minimum; the distillation recovery being 97% minimum; the distillation residue being 1.5% maximum; and the distillation loss being 1.5% maximum; b) a heat of combustion by ASTM Test Method D1405 and as calculated from Table 1 thereof of 18,720 btu per pound minimum, or a heat of combustion by ASTM Test Method D2382 of 18,700 btu per pound minimum, the latter method controlling in case of a discrepancy therebetween; c) a vapor pressure by ASTM Test Method D323 or D2551 of 5.5 psi minimum and 7.0 psi maximum; d) a copper strip corrosion by ASTM Test Method D130 of number 1, maximum; e) a potential gum (5-hour aging gum) by ASTM Test Method D873 of 6 mg per 100 mL maximum, or a potential gum (16-hour aging gum by ASTM Test Method D873) of 10 mg per 100 mL; f) a sulfur content by ASTM Test Method D1266 or D2622 of 0.05% by weight maximum; g) a freezing point by ASTM Test Method D2386 of -72°F maximum; and h) a water reaction by ASTM Test Method D1094 wherein the volume change, if any, does not exceed ± 2 mL.

Description: This invention relates to unleaded aviation gasoline compositions which satisfy the specification requirements of ASTM Specification D910-90. The specifications imposed upon aviation gasolines are necessarily extremely rigorous, since the consequences could be disastrous if an aviation gasoline does not perform properly in a spark-ignition aviation engine. While leaded aviation gasolines have performed wonderfully well in actual service for many years, many misguided persons have clamored for elimination of lead from gasoline. If their efforts succeed, the refining industry will be faced with the problem of trying to provide unleaded aviation gasoline that performs as well as leaded aviation gasoline and that does not exceed the economic constraints of the marketplace. This invention is deemed to overcome the above problem most expeditiously. In accordance with this invention, there is provided an unleaded aviation gasoline composition which comprises a blend of hydrocarbons and at least one cyclopentadienyl manganese tricarbonyl compound dissolved therein in an amount such that said gasoline composition has a minimum knock value lean rating octane number of 100 as determined by ASTM Test Method D2700 and wherein Motor Method octane ratings are converted to aviation ratings in the manner described in ASTM Specification D910-90, said composition being further characterized by having: a) a distillation temperature as determined by ASTM Test Method D86 of 10% evaporated, 75°C (167°F) maximum temperature; 40% evaporated, 75°C (167°F) maximum temperature; 90% evaporated, 135°C (275°F) maximum temperature; and a final boiling point of 170°C (338°F) maximum temperature; the sum of the 10 and 50% evaporated temperatures being 152.8°C (307°F) minimum; the distillation recovery being 97% minimum; the distillation residue being 1.5% maximum; and the distillation loss being 1.5% maximum; b) a heat of combustion as determined by ASTM Test Method D1405 and as calculated from Table 1 thereof of 4.354x10 7 J/kg (18,720 btu per pound) minimum, or a heat of combustion as determined by ASTM Test Method D2382 of 4.350x10 7 J/kg (18,700 btu per pound) minimum, the latter method controlling in case of a discrepancy therebetween; c) a vapor pressure as determined by ASTM Test Method D323 or D2551 of 3866.89 kg/m 2 (5.5 psi) minimum and 4921.49 kg/m 2 (7.0 psi) maximum; d) a copper strip corrosion as determined by ASTM Test Method D130 of number 1, maximum; e) a potential gum (5-hour aging gum) as determined by ASTM Test Method D873 of 6 mg per 100 mL maximum, or a potential gum (16-hour aging gum as determined by ASTM Test Method D873) of 10 mg per 100 mL; f) a sulfur content as determined by ASTM Test Method D1266 or D2622 of 0.05% by weight maximum; g) a freezing point as determined by ASTM Test Method D2386 of - 22.2°C (72°F) maximum; and h) a water reaction as determined by ASTM Test Method D1094 wherein the volume change, if any, does not exceed ± 2 mL. Preferred gasoline compositions are those in which the gasoline composition additionally has a minimum performance number reported to the nearest whole number and as determined by ASTM Test Method D909 of 130. In this connection, a minimum performance number of 130 is equivalent to a knock value determined using isooctane plus 1.28 milliliters of tetraethyllead per 3.79 Litres (per gallon). Another embodiment of this invention provides the method of operating a four stroke cycle, reciprocating piston aircraft engine which comprises providing or using as the fuel for said engine a gasoline composition of this invention. Cyclopentadienyl manganese tricarbonyl compounds which can be used in the practice of this invention include cyclopentadienyl manganese tricarbonyl, methylcyclopentadienyl manganese tricarbonyl, dimethylcyclopentadienyl manganese tricarbonyl, trimethylcyclopentadienyl manganese tricarbonyl, tetramethylcyclopentadienyl manganese tricarbonyl, pentamethylcyclopentadienyl manganese tricarbonyl, ethylcyclopentadienyl manganese tricarbonyl, diethylcyclopentadienyl manganese tricarbonyl, propylcyclopentadienyl manganese tricarbonyl, isopropylcyclopentadienyl manganese tricarbonyl, tert-butylcyclopentadienyl manganese tricarbonyl, octylcyclopentadienyl manganese tricarbonyl, dodecylcyclopentadienyl manganese tricarbonyl, ethylmethylcyclopentadienyl manganese tricarbonyl, and indenyl manganese tricarbonyl, including mixtures of two or more such compounds. Preferred are the cyclopentadienyl manganese tricarbonyls which are liquid at room temperature such as methylcyclopentadienyl manganese tricarbonyl, ethylcyclopentadienyl manganese tricarbonyl, liquid mixtures of cyclopentadienyl manganese tricarbonyl and methylcyclopentadienyl manganese tricarbonyl, and mixtures of methylcyclopentadienyl manganese tricarbonyl and ethylcyclopentadienyl manganese tricarbonyl. Preparation of such compounds is described in the literature, for example, U.S. 2,818,417. In another preferred embodiment the unleaded gasoline composition additionally contains at least one antioxidant in an amount not in excess of 3.8 kg per 159 m 3 (8.4 pounds per 1000 barrels), said antioxidant being selected from the group N,N'-diisopropyl-p-phenylenediamine, N,N'-di-sec-butyl-p-phenylenediamine, 2,4-dimethyl-6-tert-butylphenol, 2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butylphenol, a mixture of 75% minimum 2,6-di-tert-butylphenol plus 25% maximum di- and tri-tert-butylphenol; and a mixture of 75% minimum di- and triisopropyl phenols plus 25% maximum di- and tri-tert-butylphenol. Most preferably the amount of such antioxidant does not exceed 1.9 kg per 159 m 3 (4.2 pounds per 1000 barrels). It is to be understood that the fuels of this invention are unleaded in the sense that a lead-containing antiknock agent is not deliberately added to the gasoline. Trace amounts of lead due to contamination of equipment or like circumstances are permissible and are not to be deemed excluded from the practice of this invention. The base fuels used in the foregoing compositions can be blends of refined hydrocarbon derived from crude petroleum, natural gasoline, or blends thereof with synthetic hydrocarbons or aromatic hydrocarbons, or both. Blending components, if approved for use in aviation gasolines, such as oxygenated ingredients, can be included. Rarely, if ever, will the content of aromatic hydrocarbons in the gasoline exceed levels above 25%. As noted above, the overall composition must satisfy the requirements a) through h) inclusive as set forth above. Other components which can be employed, and under certain circumstances are preferably employed, include dyes which do not contribute to excessive induction system deposits. Typical dyes which can be employed are 1,4-dialkylaminanthraquinone, p-diethylaminoazobenzene (Color Index No. 11020) or Color Index Solvent Yellow No. 107, methyl derivatives of azobenzene-4-azo-2-naphthol (methyl derivatives of Color Index No. 26105), alkyl derivatives of azobenzene-4-azo-2-naphthol, or equivalent materials. The amounts used should, wherever possible, conform to the limits specified in ASTM Specification D910-90. Fuel system icing inhibitors may also be included in the fuels of this invention. Preferred are ethylene glycol monomethyl ether and isopropyl alcohol, although materials giving equivalent performance may be considered acceptable for use. Amounts used should, wherever possible, conform to the limits referred to in ASTM Specification D910-90. The concentration of the cyclopentadienyl manganese tricarbonyl compound used in the unleaded aviation gasoline base stock satisfying the above criteria will vary to some extent depending upon the identity and properties of the base fuel and the octane quality desired in the finished fuel. Ordinarily amounts equivalent to 0.01-0.5 gram of manganese per gallon of fuel are sufficient, although higher amounts can be used whenever deemed necessary or appropriate, provided that the resultant fuel composition satisfies the requirements of a) through h) above. Preferably the fuel will contain up to 0.25 gram of manganese per 3.79 Litres (per gallon) as one or more cyclopentadienyl manganese tricarbonyl compounds. There are good and sufficient reasons why the gasoline composition is to comply with the requirements set forth above as a) through h). The rationale behind these requirements as set forth in ASTM Specification D910-90, paragraphs X1.1.1, X1.1.3 and X1.2.1. In accordance with other preferred embodiments this invention further provides a method of operating a four stroke cycle, reciprocating piston aircraft engine which comprises providing and/or using as the fuel for said engine a gasoline composition of this invention, and providing and/or using as the lubricating oil for said engine a lubricating oil composition satisfying the chemical and physical property requirements set forth below; The chemical and physical property requirements of the lubricating oil used in the foregoing preferred aircraft engine embodiment are as follows: 1) Viscosity, m 2 /S (cSt), per ASTM D 445: SAE Grade Minimum at 100°C Less than at 100°C 30 9.3x10 -6 (9.3) 12.5x10 -6 (12.5) 40 12.5x10 -6 (12.5) 16.3x10 -6 (16.3) 50 16.3x10 -6 (16.3) 21.9x10 -6 (21.9) 60 21.9x10 -6 (21.9) 26.1x10 -6 (26.1) 2) Multigrade oil shall meet the viscosity requirements and the Low Temperature Viscosity Cold Crank Simulation requirements of SAE Test Method J300 for the designated grade. 3) Viscosity Index, minimum per ASTM D 2270: 100 for SAE grades 30, 40 and Multigrade; 95 for SAE grades 50 and 60. 4) Flash Point, °C, minimum per ASTM D 92: 220 for SAE grades 30 and Multigrade; 225 for SAE grade 40; and 243 for SAE grades 50 and 60. 5) Pour Point, °C, maximum per ASTM D 97: -24 for SAE grade 30; -22 for SAE grade 40; and -18 for SAE grades 50 and 60. 6) Viscosity, High Temperature, High Shear at 150°C, Pas (cP) minimum per ASTM D 4683, D 4741, D 4624: 3.3x10 -3 Pas (3.3) for all viscosity grades. 7) Total Acid Number, mg KOH/g, maximum (titrated to a pH 11 end point) per ASTM D 664: 1.0 for all viscosity grades. 8) Ash Content, Mass %, maximum per ASTM D 482: 0.006 for all viscosity grades. 9) Trace Sediment, mL/100 mL Oil, maximum per ASTM D 2273: 0.005 for all viscosity grades. 10) Copper Strip Corrosion, maximum rating per ASTM D 130: 1 after 3 hours @ 100°C for all viscosity grades; and 3 after 3 hours @ 204°C for all viscosity grades. 11) Foaming Tendency/Stability per ASTM D 892: Aerated Volume, mL, maximum for all viscosity grades per Sequences I, II and III: 50; Volume after 10 minutes, mL, maximum for all viscosity grades per Sequences 1, II, and III: 0. 12) Compatibility with other oils per FTM 791 Method 3403: All viscosity grades shall pass. 13) Elastomer Compatibility, % swelling, acceptable range for all viscosity grades after 72 hours per FTM 791 Method 3604 (except conducted with the specific materials and temperatures herein listed): Material Test Temperature Acceptable Limits AMS-3217/1 70°C (158°F) - 5 to + 5 AMS-3217/4 150°C (302°F) - 5 to + 5 AMS-3217/5 150°C (302°F) - 5 to + 5 US Navy Silicone Rubber 121°C (250°F) 0 to + 20 14) Trace Metal Content, ppm, maximum for all viscosity grades, per test method of Paragraph 4.5.2 of MIL-L-22851D (1 December 1990) or equivalent: Iron, 5; Silver, 3; Aluminum, 7; Chromium, 5; Copper, 3; Magnesium, 3; Nickel, 3; Lead, 5; Silicon, 25; Tin, 10; Titanium, 2; Molybdenum, 4. The most preferred lubricating oils will not only meet the above requirements 1) through 14) but in addition, will meet the following L-38 Engine Test Requirements: 15) Total Bearing Weight Loss, mg, maximum per ASTM STP 509A, Part IV for all viscosity grades: 500. 16) Used Oil Viscosity, Stripped, maximum % Change @ 40°C per ASTM D 445 for all single viscosity grades: -15 to + 10. 17) Used Oil Viscosity at 100°C of Multi-grade Oil per SAE J300 shall remain in SAE J300 grade. 18) Used Oil Total Acid Number, maximum change for all viscosity grades per ASTM D 664 (titrated to a pH 11 end point): 2.0.

Claims: An unleaded aviation gasoline composition which comprises a blend of hydrocarbons and at least one cyclopentadienyl manganese tricarbonyl compound dissolved therein in an amount such that said gasoline composition has a minimum knock value lean rating octane number of 100 as determined by ASTM Test Method D2700 and wherein Motor Method octane ratings are converted to aviation ratings in the manner described in ASTM Specification D910-90, said composition being further characterized by having: a) a distillation temperature as determined by ASTM Test Method D86 of 10% evaporated, 75°C (167°F) maximum temperature; 40% evaporated, 75°C (167°F) maximum temperature; 90% evaporated, 135°C (275°F) maximum temperature; and a final boiling point of 170°C (338°F) maximum temperature; the sum of the 10 and 50% evaporated temperatures being 152.8°C (307°F) minimum; the distillation recovery being 97% minimum; the distillation residue being 1.5% maximum; and the distillation loss being 1.5% maximum; b) a heat of combustion as determined by ASTM Test Method D1405 and as calculated from Table 1 thereof of 4.354x10 7 J/kg (18.720 btu per pound) minimum, or a heat of combustion as determined by ASTM Test Method D2382 of 4.350x10 7 J/kg (18,700 btu per pound) minimum, the latter method controlling in case of a discrepancy therebetween; c) a vapor pressure as determined by ASTM Test Method D323 or D2551 of 3866.89 kg/m 2 (5.5 psi) minimum and 4921.49 kg/m 2 (7.0 psi) maximum; d) a copper strip corrosion as determined by ASTM Test Method D130 of number 1, maximum; e) a potential gum (5-hour aging gum) as determined by ASTM Test Method D873 of 6 mg per 100 mL maximum, or a potential gum (16-hour aging gum as determined by ASTM Test Method D873) of 10 mg per 100 mL; f) a sulfur content as determined by ASTM Test Method D1266 or D2622 of 0.05% by weight maximum; g) a freezing point as determined by ASTM Test Method D2386 of -57.8°C (-72°F) maximum; and h) a water reaction as determined by ASTM Test Method D1094 wherein the volume change, if any, does not exceed ± 2 mL. A composition as claimed in Claim 1 wherein said gasoline composition has a minimum knock value lean rating octane number of 100 as determined by ASTM Test Method D2700 and a minimum performance number reported to the nearest whole number and as determined by ASTM Test Method D909 of 130. A composition as claimed in Claim 1 wherein said cyclopentadienyl manganese tricarbonyl compound consists essentially of methylcyclopentadienyl manganese tricarbonyl. The method of operating a four stroke cycle, reciprocating piston aircraft engine which comprises A) providing or using as the fuel for said engine an unleaded aviation gasoline composition which comprises a blend of hydrocarbons and at least one cyclopentadienyl manganese tricarbonyl compound dissolved therein in an amount such that said gasoline composition has a minimum knock value lean rating octane number of 100 as determined by ASTM Test Method D2700 and wherein Motor Method octane ratings are converted to aviation ratings in the manner described in ASTM Specification D910-90, said composition being further characterized by having: a) a distillation temperature as determined by ASTM Test Method D86 of 10% evaporated, 75°C (167°F) maximum temperature; 40% evaporated, 75°C (167°F) maximum temperature; 90% evaporated, 135°C (275°F) maximum temperature; and a final boiling point of 170°C (338°F) maximum temperature; the sum of the 10 and 50% evaporated temperatures being 152.8°C (307°F) minimum; the distillation recovery being 97% minimum; the distillation residue being 1.5% maximum; and the distillation loss being 1.5% maximum; b) a heat of combustion as determined by ASTM Test Method D1405 and as calculated from Table 1 thereof of 4.354x10 7 J/kg (18,720 btu per pound) minimum, or a heat of combustion as determined by ASTM Test Method D2382 of 4.350x10 7 J/kg (18,700 btu per pound) minimum, the latter method controlling in case of a discrepancy therebetween; c) a vapor pressure as determined by ASTM Test Method D323 or D2551 of 3866.89 kg/m 2 (5.5 psi) minimum and 4921.49 kg/m 2 (7.0 psi) maximum; d) a copper strip corrosion as determined by ASTM Test Method D130 of number 1, maximum; e) a potential gum (5-hour aging gum) as determined by ASTM Test Method D873 of 6 mg per 100 mL maximum, or a potential gum (16-hour aging gum as determined by ASTM Test Method D873) of 10 mg per 100 mL; f) a sulfur content as determined by ASTM Test Method D1266 or D2622 of 0.05% by weight maximum; g) a freezing point as determined by ASTM Test Method D2386 of -57.8°C (-72°F) maximum; and h) a water reaction as determined by ASTM Test Method D1094 wherein the volume change, if any, does not exceed ± 2 mL. A method as claimed in Claim 4 wherein said gasoline composition has a minimum knock value lean rating octane number of 100 as determined by ASTM Test Method D2700 and a minimum performance number reported to the nearest whole number and as determined by ASTM Test Method D909 of 130. A method as claimed in Claim 4 wherein said cyclopentadienyl manganese tricarbonyl compound consists essentially of methylcyclopentadienyl manganese tricarbonyl. The method of operating a four stroke cycle, reciprocating piston aircraft engine according to claim 4 which additionally comprises: providing and/or using as the lubricating oil for said engine a lubricating oil composition satisfying the following chemical and physical property requirements: 1) Viscosity, m 2 /S (cSt) per ASTM D 445: SAE Grade Minimum at 100°C Less than at 100°C 30 9.3x10 -6 (9.3) 12.5x10 -6 (12.5) 40 12.5x10 -6 (12.5) 16.3x10 -6 (16.3) 50 16.3x10 -6 (16.3) 21.9x10 -6 (21.9) 60 21.9x10 -6 (21.9) 26.1x10 -6 (26.1) 2) Multigrade oil shall meet the viscosity requirements and the Low Temperature Viscosity Cold Crank Simulation requirements of SAE Test Method J300 for the designated grade. 3) Viscosity Index, minimum per ASTM D 2270: 100 for SAE grades 30, 40 and Multigrade; 95 for SAE grades 50 and 60. 4) Flash Point, °C, minimum per ASTM D 92: 220 for SAE grades 30 and Multigrade; 225 for SAE grade 40; and 243 for SAE grades 50 and 60. 5) Pour Point, °C, maximum per ASTM D 97: -24 for SAE grade 30; -22 for SAE grade 40; and -18 for SAE grades 50 and 60. 6) Viscosity, High Temperature, High Shear at 150°C, Pas (cP), minimum per ASTM D 4683, D 4741, D 4624: 3,3x10 -3 Pas (3.3) for all viscosity grades. 7) Total Acid Number, mg KOH/g, maximum (titrated to a pH 11 end point) per ASTM D 664: 1.0 for all viscosity grades. 8) Ash Content, Mass %, maximum per ASTM D 482: 0.006 for all viscosity grades. 9) Trace Sediment, mL/100 mL Oil, maximum per ASTM D 2273: 0.005 for all viscosity grades. 10) Copper Strip Corrosion, maximum rating per ASTM D 130: 1 after 3 hours @ 100°C for all viscosity grades; and 3 after 3 hours @ 204°C for all viscosity grades. 11) Foaming Tendency/Stability per ASTM D 892: Aerated Volume, mL, maximum for all viscosity grades per Sequences I, II and III: 50; Volume after 10 minutes, mL, maximum for all viscosity grades per Sequences 1, II, and III: 0. 12) Compatibility with other oils per FTM 791 Method 3403: All viscosity grades shall pass. 13) Elastomer Compatibility, % swelling, acceptable range for all viscosity grades after 72 hours per FTM 791 Method 3604 (except conducted with the specific materials and temperatures herein listed): Material Test Temperature Acceptable Limits AMS-3217/1 70°C (158°F) - 5 to + 5 AMS-3217/4 150°C (302°F) - 5 to + 5 AMS-3217/5 150°C (302°F) - 5 to + 5 US Navy Silicone Rubber 121°C (250°F) 0 to + 20 14) Trace Metal Content, ppm, maximum for all viscosity grades, per test method of Paragraph 4.5.2 of MIL-L-22851D (1 December 1990) or equivalent: Iron, 5; Silver, 3; Aluminum, 7; Chromium, 5; Copper, 3; Magnesium, 3; Nickel, 3; Lead, 5; Silicon, 25; Tin, 10; Titanium, 2; Molybdenum, 4.

Inventors: HENDERSON DOUGLAS HAROLD, HENDERSON, DOUGLAS HAROLD
Applicants: ETHYL PETROLEUM ADDITIVES INC, ETHYL PETROLEUM ADDITIVES, INC.
Application year: 1992
Main classification: C10L1
IPC codes: C10L10, C10L1