US3009790A

US3009790A - Fuel for spark ignition engines

Info

Publication number: US3009790A
Application number: US650838A
Authority: US
Inventors: Jr John P Pellegrini; Helen I Thayer
Original assignee: Gulf Research and Development Co
Current assignee: Gulf Research and Development Co
Priority date: 1957-04-05
Filing date: 1957-04-05
Publication date: 1961-11-21
Anticipated expiration: 1978-11-21
Also published as: BE566072A; CH380438A; FR1205289A; GB867789A; LU35910A1; DE1065216B; NL112686C

Description

United States Patent 3,009,790 FUEL FOR SPARK IGNITION ENGINES John P. Pellegrini, Jr., and Helen I. Thayer, Pittsburgh,

Pa., assignors to Gulf Research & Development Company, Pittsburgh, Pa., a corporation of Delaware No Drawing. Filed Apr. 5, 1957, Ser. No. 650,838

11 Claims. (Cl. 44-58) This invention relates to fuels and more particularly to leaded gasolines for high-compression, spark ignition engines.

It has long been recognized that for greater economy with respect to fuel requirement and greater efiiciency in the operation of a gasoline-powered, spark ignition engine high-compression ratios are desired. As a result, several automobile manufacturers have increased the compression ratios of their spark ignition engines to 8.5 :1 and even as high as :1, the future trend of the automotive industry indicating that substantially all engines will beoperating at such high or higher compression ratios in the foreseeable future. In order to obtain smooth engine operation at these high compression ratios under various driving conditions itis necessary to employ a fuel having high octane numbers as determined by both the motor method (ASTM: D357-53) and theresearch method (ASTM: D908-55).

Smooth operation at'high speeds under open-road conditions in modern high-compression engines usually requires a fuel having a motor octane number of at least about 85. Smooth operation in the same engines at lower speeds under city driving conditions where frequent accelerations are encountered usually requires a fuel having a research octane number of at least about 95. An opti- I mum fuel for present dayuse is thus one which has a re-.

search octane number of at least about 95"and a'sensitivity of about 8 to 12. 'By sensitivity, we intend to indicate the spread or differential between the octane numbers as determined by the motor method and the research method. Of course, if fuels are available whose motor and research octane numbers coincide at levels of 95 or more, the sensitivity ,of such fuels can bein the order of'l to 2 or less and still result in desirable fuels for use in high-compression engines under both low:

speed and high-speed operation. a

In order to obtain fuels having both high motor and high research octane numbersthe petroleum industry has developed numerous petroleum hydrocarbon conversion processes among which may be mentioned cracking, alkylation, ,aromatization, cyclization, isomerization, hydrogenatio'n, dehydrogenation, hydroisomerization, poly- 3,009,790 Patented Nov. 21, 1961 ICC fuels or a blend of fuels obtained by one or more of the above-mentioned hydrocarbon conversion processes. However, a small amount of straight-run gasoline, in some instances, may be blended with the fuels obtained by a conversion process.

To improve still further the octane ratings of the fuels obtained by the various conversion processes, the petroleum industry, in most instances, has resorted to the use of various anti-knock agents among which is tetraethyl lead. While the addition of tetraethyl lead to gasolines obtained by one or more conversion processes improves their motor and research octane numbers, the resulting fuels have certain disadvantages arising from the presence of the lead. One of the chief objections to the use of gasolines containing tetraethyl lead, i.e., leaded gasolines, arises from the tendency of such fuels upon being burned to form decomposition products of tetraethyl lead, a portion of which products aredeposited on the walls of the combustion chambers of the engine and on the electrodes and insulators of the spark plugs, thus reducing the efiiciency of the engine and offsetting to some extent the increased efficiency obtained by using an engine having a high compression ratio.

In an attempt to overcome the detrimental effect of the deposits of tetraethyl lead decomposition-products in an engine, various scavenging agents have been added to the fuel to change the form of the tetraethyl lead decomposition products to those which are more volatile and thus less likely to be deposited within the engine. For example, various volatile alkyl halides such as ethylene dibromide and/ or ethylene dichloride have been used with tetraethyl lead to produce the corresponding halides of lead-which are more volatile than the oxides. The

volatile alkyl halides, however, have not completely overis frequently evidenced by engine knocking. The knocking thus encountered is that associated with preignition of the fuel in the combustion chamber of a spark ignition engine. This knocking associated With preignition should I not be confused with knocking due to explosive auto I ignition of the unburned portion of the fuel-air mixture merization, hydrodesulfurization,reforming, hydroforming, polyforming, Platforming and combinations of two or more of such processes. These processes produce hydrocarbons boiling in the gasoline boiling point range which have engine performance characteristics markedly superior to the charge stock and to comparable boiling hydrocarbons found in straight-run gasolines. In general, straight-run gasolines are more paraffinic and less olefinic and aromatic than gasolinesobtained, for example, by a cracking process. Straight-run gasolines, per'se,

even'when fortified with tetraethyl lead generally do not give the high motor and research octane numbers re quired for smooth performance in present day engines. This ,invention is concernedprimarily, therefore, with to be traversed by the normal flame from the spark plug] We have found that a motor fuel, and particularly a gasoline obtained by a conversion process and containing tetraethyl lead in an amount suflicient to produce a gaso line fuel composition having amotor octane number of at least about and a research octane number of at least about is markedly improved'withrespect to its preignition characteristics by incorporating therein a small amount of a tri(alkoxyalkyl) following structural formula:

R1 R2 R- o-oHcn ',o

R R, -(O-(ilHCH):O-P=0 U R, R,

-(00HCH),0

phosphate having the 3 7 wherein R, R and R are alkyl groups containing about 1 to about carbon atoms, R and R are selected from the group consisting of hydrogen and alkyl groups con taining about 1 to about 3 carbon atoms and x is an integer from 1 to 2.

We prefer to employ the tri(alkoxyalkyl) phosphates which are soluble in gasoline and substantially insoluble in water, since gasoline occasionally comes in contact with water thus giving rise to the possible loss of watersoluble tri(alkoxyalkyl) phosphates. Water-solubility of the tri(alkoxyalkyl) phosphates is dependent to a large extent upon the sum of the number of carbon atoms in the groups designated as R, R and R in the structural formula shown above. Thus, while the sum of the carbon atoms in R, R and R" can be between 3 and 30, the sum of the carbon atoms to insure substantial water-insolubility is at least 8. The sum of the carbon atoms in the three groups is at least 6 but can be 6 to 24. The higher mo phosphate, in preparing gasoline fuel compositions of the invention, these compounds are water soluble and therefore are subject to loss from a fuel composition containing them if the composition comes in contact with water. For this reason, tri(methoxyethyl) phosphate and tri- (ethoxyethyl) phosphate are less desirable than a compound such as di(et'hoxyethyl) butoxyethyl phosphate, tri(propoxyethyl) phosphate or tri(butoxyethyl) phos; phate. The latter compound, for example, is completely soluble in gasoline at 25 C., and has a solubility in water at 25 C. of only about 0.11 percent.

The groups designated as R, R and R" in the struc tural formula shown hereinabove can be either alike or different. Likewise, R and R can be either alike or different groups. From the standpoint of preparation, however, compounds are preferred where R=R=R.

Specific examples of some of the tri(alkoxyalky1) phosphates which can be used in accordance with our invention are I Tri(methoxyethyl) phosphate Tri(1-methoxy-2-propyl) phosphate Tri-(Lmethoxy-l-butyl) phosphate T ri(1-methoxy-2-butyl) phosphate Tri(2-metl1oxy-3-butyl) phosphate Tri(2-methoxy-'1-pentyl) phosphate Tri(3-methoxy-2-hexy-l) phosphate Tri(3-meth0xy-4-heptyl) phosphate Tri(4-methoxy-5-octyl) phosphate Di(rnethoxyethyl) propoxyethyl phosphate Di(methoxyethyl) butoxyethyl phosphate Di(propoxyethyl) methoxyethyl phosphate Di(propoxyethyl) butoxyethyl phosphate Tri(ethoxyethy-l) phosphate Tri(2-ethoxy-l-propyl) phosphate Tri(1ethoxy-2-butyl) phosphate Tri(3-ethoXy-2-hexyl) phosphate Tri(4-ethoxy-3-heptyl) phosphate Tri(propoxyethyl) phosphate Tri(1-propoxy-2-propy1) phosphate Tri(2-propoxy-3-butyl) phosphate 4 Tri(3-propoxy-4-heptyl) phosphate 'I ri(but0xyethyl) phosphate Tri(2-butoxy-1-propyl) phosphate Tri(2-butoxy-3-butyl) phosphate Tri(4-butoxy-3-heptyl) phosphate I Tri(4-butoxy-5-octyl) phosphate Tri-(pentoxyethyl) phosphate Tri(hexoxyethyl) phosphate Tri(heptoxyethyl) phosphate Tri(octoxyethyl) phosphate Tri(nonoxyethyl) phosphate Tri(decoxyethyl) phosphate Tri(ethoxyethoxyethyl) phosphate Tri[2-(2-ethoxy-l-propoxy)-l-pr0pyl] phosphate Tri{2-(2-ethoxy-3-butoxy)-3-butyl] phosphate Tri[3(3-ethoxy-2-hexoxy) -2-hexyl] phosphate Tri[3-(3-propoxy-2-butoxy)-2-butyl] phosphate Tri[4-(4-propoxy-3-hexoxy) -3-hexyl] phosphate Tri[2-(2-butoxy-1-propoxy)-1-propyl] phosphate Tri[3-(3-butoxy-2-butoxy)-2-butyl] phosphate Tri[4-(4-butoxy-3-hexoxy)-3-hexyl] phosphate The tri(alkoxyalkyl) phosphates can readily be prepared by conventional means including reacting phosphorus oxychloride with the desired alkoxyalkyl alcohol. The following procedures are typical for preparing the tri- (allsoxyalkyl) phosphates which can 'be used in the fuel compositions of the invention.

TRI METHO-XYETHYL) PHOSPHATE 20.2 parts by weight of phosphorus oxychloride are gradually added to parts by weight of methoxyethanol while the mixture is stirred and the temperature held at about 5 to 10 C. Nitrogen gas then is passed through the mixture for eight hours at room temperature to remove hydrogen chloride. Upon completion of the reaction anhydrous sodium carbonate is added until the reaction mixture is neutral.- The tri(rnethoxyethyl). phosphate then is isolated by filtering the mixture, and distilling the filtrate in vacuo, first at 100 mm. Hg to remove the excess alcohol and other low boiling by-prodnets, and then at 1 mm. Hg. The boiling point of the product thus obtained is to 13-6. C. at 1 mm. Hg.

The product is a colorless liquid and has an index of refraction of 1.4352 at 20 C. The phosphorus content of the product so obtained is 11.11 percent as compared with the theoretical amount of 11.37,. The yield is about.

sixty-five percent of theory.

TRI(BUTOXYETHYL) PHOSPHATE To 100 pants by weight of butoxyethanol 21.7 parts by weight of phosphorus oxychloride are added dropwise while maintaining the temperature of the mixture at 10 C. or lower. The reaction mixture is then heated to 60.? C. and held at this point for three hours. The hydrogen chloride evolved is conveniently removed by a gas absorption trap. The mixture is then cooled'to room tcm-,

perature andan aqueous solution of sodium bicarbonate 1s added until the reaction mixture is neutral. The organic layer is' separated, water washed and distilled in vacuo. After the excess alcohol has been removed, the

erties of the tr i(butoxyethyl) phosphate so obtained are as follows:

Freezing point, C --70 Pour point, C 65 Flash point, F

l 340 Fire point, F 470 Viscosity at 20 C., centipoises 1 1.7 Surface tension at. 20 C., dynes/cm 28.8

TRI ETHOXYETHOXYETHYL) PHOSPHATE Into 100 parts by weight of ethoxyethoxyethanol 1 1,4 i

parts by weight of phosphorus oxychloride are added dropwise while the mixture is stirred and the temperature kept at 20 to 30 C. The mixture is then blown with nitrogen for three to four hours tov remove hydrogen chloride and the temperature raised to 50 to 60 C. The reaction mixture is cooled to room temperature and anhydrous sodium bicarbonate is added until the reaction mixture is neutral. After separating the solids by filtration, the filtrate is distilled at 60 to 70 mm. pressure to remove the excess alcohol until the pot temperature reaches about 140 C. The tri(ethoxyethoxyethyl) phosphate which remains in the pot is not distilled, but is sufliciently pure for use in the compositions of the invention as obtained. The product is a light yellow oil having a phosphorus content of 7.50. The theoretical phosphorus content is 6.93. The yield is about ninety to ninety-five percent of theory.

The amount of tri(alkoxyalkyl) phosphate required to impart improved preignition characteristics to the gasoline fuels, i.e., hydrocarbon mixtures boiling in the gasoline boiling range, depends upon the tetraethyl lead content of the particular fuel encountered, and upon the particular tri(alkoxyalkyl) phosphate which is selected. For this reason, the amount is more significant and can be more accurately expressed in terms of that which is theoretically required to convert the lead introduced into the fuel in the form of tetraethyl lead to lead orthophosphate. While improved results can be obtained with very small amounts, amounts corresponding to at least about 0.1 times that theoretically required to convert the lead to lead phosphate are preferred. Especially good results are obtained by using about 0.2 to about 0.5 times the theoretical amount required. In general, we pre fer to use an amount not more than the amount theoretically required to convert all of the lead to lead orthophosphate. Amounts greater than the theoretical amount can be employed, but for economic reasons, we prefer to use only the amount required to give the desired improvement. Therefore, we prefer to employ an amount equal to about 0.2 to about 0.5 times that theoretically required to convert the lead to lead orthophosphate. In view of the fact that the amount of tetraethyl lead in the gasoline varies from one fuel to another, it is difiicult to'state on a weight basis the amount of a particular compound based upon the weight of the gasoline. However, once knowing the amount of tetraethyl lead present in the gasoline, it is an easy matter to calculate the amount of the particular compound required on a weight basis. Mos-t gasolines on the market today contain between about one and about three cubic centimeters of tetraethyl. lead per gallon of gasoline. Based upon a gasoline having a gravity of about 54 API and containing about one cubic centimeter of tetraethyl lead, we have determined that the amount of the tri- (butoxyethyl) phosphate corresponding to 0.1 to 1.0 theories is about 0.0047 to about 0.047 percent by weight based on the gasoline. It the same gasoline contains 3 cubic centimeters of tetraethyl lead, then the tri(butoxyethyl) phosphate for 0.1 to 1.0 theories is about 0.014 to about 0.14 percent by weight. Thus, the normally useful concentration range for a 54 API gasoline containing about 1 to about 3 cubic centimeters of tetraethyl lead is about 0.0047 to about 0.14 percent. Although greater concentrations can be employed to advantage in some instances, no additional benefits with respect to preignition are achieved by the use of greater concentrations. For most currently marketed commercial gasolines, about-0.003 to about 0.45 weight percent of the tri(-alkoxyalkyl) phosphate is usually suflicient to achieve a satisfactory reduction in the engine preignition tendencies of the fuel. The amount within this range should, of course, be suflicient toincorporate between about 0.1 and about 1.0 times that theoretically required to convert the lead to lead phosphate.

a It will be understood, amount on a weight basis for one particular compound may not be the optimum amount for another compound.

One reason for this is that the efiectiveness of the COD):

pounds may vary from one compound to another. Another reason is that the molecular Weight of one com-' pound may be twice the molecular weight of another compound,-so that to obtain an equivalent amount 04? phosphorus when using the compound having the greater molecular weight, one is required to use twice the amount In any event, the amountof the tri(a1koxyaikyl) phosphate used is suflicient of compound on a weight basis.

to give marked preignition improvement.

The tri(alkoxyalky1) phosphate can be either chemically pure or it can comprise a commercial product which may contain a small amount of the alkoxyalkanol from which the corresponding tri(alkoxy alkyl) phosphate was prepared or other neutral impurities. For example, when using tri(butoxyethy1) phosphate, a small amount of butoxyethanol can be present without deleteriously affecting the improved preigniu'on characteristicsof the fuel.

The gasoline fuel composition to which the tri(alkoxyalkyl) phosphate is added comprises a mixture of hydrocarbons boiling in the gasoline boiling range having a motor octane number (leaded) i of at least about 85 and a research octane number (leaded) of at least about 95. The mixture of hydrocarbons can be obtained by at least one of the petroleum conversion processes including cracking, alkylation, aromatization, cyclization, isomerizatiorn, hydrogenation, dehydrogenation, hydroisomerization, polymerization, hydrodesulfurization, reforming, hy-

drofotrming, polyforming, Platforming, and combinations of two or more such processes, as well as by the Fischer-Tropsch and related processes. While current straight-run gasoline has octanenumbers too low to qualify as the sole'hydrooarbon component of gasoline fuel compositions within the scope of this invention, a-

small amount of straight-run gasoline can be blended with the hydrocarbon mixture obtained by one or more of the designated conversion processes provided the resulting mixture has a motor octane number (leaded) of at least about and a research octane number (leaded) of at least about 95. A preferred gasoline fuel composition comprises a blend of hydrocarbons obtained by catalytic cracking, Platfocrming and alkylation processes.

In addition to the tri(a1koxyalkyl) compound and tetraethyl lead, the gasoline fuel composition of our invention can contain other gasoline improvement agents including upper cylinder lubricants, corrosion and oxidation inhibitors, conventional alkyl halide lead scavenging agents, alcoholic anti-stalling agents,,metal deactivators, dehazing .agents, anti-rust additives, other ignition control agents,

dyes and the like.

When an upper cylinder lubricant is employed it is genorally used in an amount of from about 0.25 to about 0.75

percent by volume of the composition, e.g., 0.5 volume percent. This oil should bea light lubricating oil distillate, e.g., one having a viscosity at F. of from about 50 to about 500 Saybolt Universal'seconds, e.g., about 100 SUS. Although highly paraflinic lubricating distillates can be used, lubricating distillates obtained from Coastal or naphthenic type crudeoils are preferred because of their superior solvent properties. The lubricating oil can be solvent-treated, acid-treated, or'otherwise refined.

When an oxidation inhibitor is desired, any of the conventional inhibitors can be utilized. The alkylated phenols, e.g., 2,4,o-tni-tertiary-butylphenol, 2,6-di-tertiarybutyl-4-methylphenol, 2,2-bis(2-hydroxy-3-tertiary-butyl- 5-methylphenyl) propane and bis(2-hydroxy-3-tertiarybutyd-S-methylphenyl) methane, because of their hydrocarbon-solubility and water-insolubili-ty characteristics are preferred oxidation inhibitors. Such inhibitors when used are incorporated in the gasoline fuel composition in of course,- that the optimum amounts. of from about 0.001 to about 0.02 percent by weight of the composition, e.g., 0.007 weight percent.

Exemplary of other specific improvement agentswhich we can use are N,N-disalicylidene-1:Z-diaminopropane as a metal deactivator and the cocoamine salt of isoamyl octyl acid orthophosphate as a rust inhibitor agent. The

metal ,deactivator. is generally used in small amounts of the, order of about 0.0003 to about 0.001 percent by weight based on the fuel composition. The rust" inhibitor is generally'used in small amounts ofthe order of about 0.002'to about 0.008 percent by weight based on the fuel composition.

The cocoamine salt of isoamyl octyl. acid orthophosphate and its preparation are fully described in U.S.

Patent .No. 2,371,851 which issued. on March 20, 1945, to Herschel G. Smith and Troy L. Cantrell. As disclosed in said patent, the cocoamine salt of isoamyl octylacid phosphate can be'readily prepared by reacting cocoamine with isoamyl octyl acid orthophosphate in approximately equimolecular ratios, the reaction being so controlled as to produce substantially neutral reaction mixtures having a pH value within the range of 5.5 to 7.5, as illustrated in Examples. 1 and 2 of that patent. ture of amines prepared from coconut oil fatty acids, and contains. a predominant amount of n-dodecyl amine (l auryl amine), together with minor amounts of n-octyl, n-decyl, n-tetradecyh. n-hexadecyl, n-octadecyl, and noctadecenylamines. The isoamyl octyl acid phosphate employed in a di-ester of onthophosphoric acid having the following structural formula:

I n n n o H H HaC-( 3( J( l-Oi O-(il( J-CiHo omen (in it can hol, isopropyl alcohol, isooctyl alcohol, decyl alcohol,-

methylal, acetal, propylal and isopropylal, tetraethoxy propane, dimethyl metal of isooctyl aldehyde, ethyl ether, cyclohexano-l, acetone, an alkoxyalkanol, or the like. The concentrate, of course, can contain other conventional gasoline. -improvement agents, such as anti-oxidants, typical anti-stalling agents, anti-knock agents, ametal deactivator, an: upper cylinder lubricant, an alkylhalide lead scavenging agent, a dehazing agent, anti-rust additives, other ignition control agents, dyes and the like. Since the amount of tri(alkoxyalkyl) phosphate depends to some extent upon the amount of the tetraethyl lead present, this method of adding the compound to the gasoline serves as a convenient way of adding the;.correct amount of tri(alkoxyalkyl) phosphate and tetraethyl leadsimultaneously. Thus, a gasoline-benefiting concentrate can be.

made by admixing tetraethyl lead or commercially available mixtures of tetraethyl lead and a halide of ethylene with the tri(alkoxyalkyl) phosphate wherein the tri(alk- Cocoamine is a mixoxyalkyl) phosphate is present in an amount bet-ween about 0.1 and about 1.0 times the theoretical amount required to convert the lead of the tetraethyl lead to lead orthophosphate.

The proportions of the constituents in such a gasolinebenefiting concentrate may vary depending upon the characteristics of the base gasoline to which the concentrate is to be added as well as the compression ratio of the engine in which the gasoline is to be used. Good results can be obtained, however, with a composition consistingof about 23 to about 60 percent by weight of tetraethyl lead, about 13 to about 36 percent by weight of a mixture of ethylene halides and about 3 to about 63 percent by weight of a -tn'(alkoxyalkyl) phosphate, the

tri(alkoxyalkyl) phosphate being present in at least 10.1

times the theoretical amount required to convert the lead in the tetraethyl lead to lead phosphate.

One convenient method of preparing a gasoline-benefiting concentrate is to start with a commercially available product comprising tetraethyl lead and the halides of ethylene. One such commercially available product consists of about 61.5 percent by'weight of tetraethyl lead, about 17.9 percent by Weight of ethylene dibromid'e and about 18.8 percent by weight of ethylene dichloride.

This commercially available product has a specific gravity Grams Percent by Weight Tetraethyl lead 4. 94 53. 2 Ethylene dibromide 1. 43 15.4 Ethylene dichloride l. 51 16. 3 Tri(butoxyethyl) phosphate 1. 23 13. 3

Toincorporate three cubic centimeters of tretaethyl lead in a gallon of gasoline, the above concentrate is added to the base gasoline in amounts of about 9.26 grams per gallon. The gasoline-benefiting concentrate thus prepared exhibited no deterioration upon prolonged storage in the dark at room temperature.

The amount of the gasoline-benefiting concentrate added to gasoline will vary depending upon the octane improvement desired; Ordinarily, however, the concentrate is added in an amount sufficient to incorporate between about one and about three cubic centimeters of tetraethyl lead in a gallon of gasoline.

Although the tn'(alkoxyalkyl) phosphates of this invention are utilized primarily as preignition agents, they are additionally useful in that they give increased valve life and spark plug life andthey impart valuable anti-rust, oxidation stability and anti-stalling properties to gasoline compositions when used in preignition-inhibiting amounts.

The gasoline compositions of this invention and their preparation are illustrated in detail by the following specific examples.

Example I A gasoline composition having excellent preignition characteristics was prepared by incorporating 0.825 gram of tri(butoxyethyl) phosphate in a gallonof the base gasoline (approximately 0.029 weight percent). The base gasoline was a blended gasoline made up of catalyti cally cracked gasoline, alkylate and Platformate. The base gasoline contained about 3 cubic centimeters (4.94 grams) of tetraethyl lead per gallon of gasoline. addition, the base gasoline contained as a oxidation inhibitor 2,6-di-tertiary-butyl-4-methylphenol (30 lbs/1000 bbls.) and as ametal deactivator N,N'-disalicylidene 1:2-diaminopropane (l lb./1000 bbls.). The tri(-butoxyethyl) phosphate thus comprised about 0.2 times the theoretical amount required to convert the lead of the tetraethyl lead to lead orthophosphate. Typical samples of the base gasoline and the base gasoline containing 0.029 percent of the tri(butoxyethyl) phosphate had the following inspections:

With no With tri (bu- 0.029% trl toxyethyl) (butoxyphosphate ethyl) phosphate Gravity, API 53. 7 54. Sp. gr., 60/60 F 0. 7640 O. 7628 Sulfur, L, percent 0. 04 0. 04 Copper strip test, 122 F., 3 hrs 1A 1A Copper dish gum: mg./100 m1. ASTM: D910- 53T g 1 4g Existent gum, mg./l00 ml Oxidation stability, min.. 733 861 Bromine number 32 34 Knock rating:

Motor method 89.3 89. 0 Research method 99. 7 99. 4 TEL, mL/gal 3. 04 3. 04 Vapor pressure, Reid, lb 5. 5. 3 Distillation, gasoline:

Over point, F 104 112 End point, F 374 377 evap. at F 161 162 50 245 244 90" 309 818 Recovery- 99. 2 98. 2 Residue 0. 5 1. 2

1 This increase over the base gasoline is not indicative of an increase in gum formation. Reason for increase is that tr1(butoxyethyl) phosphate is not volatile under the conditions of the gum test.

Example II Another suitable composition was prepared in the manner of the foregoing Example I by incorporating 1.24 grams of tri(butoxyethyl) phosphate in a gallon of the base gasoline (approximately 0.043 weight percent). The tri(butoxyethyl) phosphate thus comprised about 0.3 times the theoretical amount required to convert the lead to lead orthophosphate. 3

Example III Another composition was prepared in the manner of the foregoing Example I by incorporating 1.65 grams of tri(butoxyethyl) phosphate in a gallon of base gasoline (approximately 0.057 weight percent). The tri(butoxyethyl) phosphate thus comprised about 0.4 times the theoretical amount required to convert the lead to lead orthophosphate.

Example IV An additional composition was prepared in the manner of the foregoing Example I by incorporating 4.14 grams of tri(butoxyethyl) phosphate in a gallon of gasoline. The tri(butoxyethyl) phosphate thus comprised about 1.0 times the theoretical amount required to convert the lead to lead orthophosphate.

Example V An additional gasoline composition having excellent preignition characteristics combined with good uppercylinder lubrication was prepared by adding a lubricating oil distillate to the base gasoline and then incorporating in the oil-containing gasoline fuel composition 1.24 grams of tri(butoxyethyl) phosphate per gallon of gasoline fuel composition (approximately 0.043 weight percent). The

Gravity, API L-bs./gal., 60 F Example VI Other suitable compositions were prepared by admixture of the cocoamine salt of 3-methylbutyl Z-ethylhexyl or-thophosphoric acid to the oil-containing gasoline fuel composition of Example V. The cocoamine dialkyl o-phosphate (84 weight percent oil concentrate) in these compositions was added to the gasoline in the ratios of about 5 pounds and about 16 pounds per 1000 barrels (approximately 0.0019 and 0.0060 percent by weight active component).

Example VII Another satisfactory composition in accordance with this invention was prepared in the manner set forth in the foregoing examples by incorporating in the base gasoline 0.564 gram (approximately 0.020 weight percent) of tri- (methoxyethyl) phosphate. The tri(methoxyethy1) phosphate thus comprised about 0.2 times the theoretical amount required to convert the lead to lead orthophosphate.

Example VIII Another satisfactory composition was prepared as indicated in Example VII, except that tri(octoxyethyl) phosphate was used as the preignition inhibitor.

Example IX Another satisfactory composition was prepared as indicated in Example VII, except that tri(ethoxyethoxyethyl) phosphate was used as the preignition inhibitor.

' Example X Another satisfactory composition is prepared as indiciate'd in ExampleVII, except that tri(3-methoxy-'4- heptyl) phosphate is used as the preignition inhibitor.

Example XI Example XIV Another satisfactory gasolinecomposition is prepared by admixture of approximately 0.038 percent by weight of the composition of tri(propoxyethyl) phosphate with a base gasoline fuel composition having a lead content of about 3 cubic centimeters of tetraethyllead per gallon and containing 0.5 volume percent of a SUS at 100 F. (approximate) lubricating distillate oil obtained from I.

a Coastal type crude.

Example XV Another-satisfactory gasoline composition is prepared substantially identically as indicated in Example XIV except that tri(octoxyethyl) phosphate is used as the preignition inhibitor.

The compositions described in the foregoing examples are illustrative only, and other tri(all oxyalkyl) phosphates disclosed herein can be substituted in the foregoing specific compositions in the same or equivalent concentrations with goodresults.

An appreciable reduction-in preignition due to tetraethyl lead decomposition product deposits is achieved by the use of the foregoing gasoline fuel compositions in internal combustion engines of the gasoline-powered, spark ignition type. For example, when the compositions described in the examples are burned in an internal combustion engine operated under conditions wherein noise, includingpreignition, knock or rumble would normally be encountered such engine noise is markedly less than the noise encountered when the base gasoline is used alone.

In order to illustrate the improved preignition characteristicscbtained with a fuel of the invention, a test was employed in which the fuel was burned in four commercially available spark-ignition engines. These engines, with the exception of Engine C which had a compression ratio of 8.5 to 1, each had a compression ratio of 10 to 1. In this test, the engines were operated on a cycling schedule consisting of three minutes at 1500 r.p.m. at a 15 brake horsepower load, followed by a one-minute idle at 450 rpm. The spark advance i-n-each instance was the manufacturers setting. The coolant temperatures in and out were 150 and 160 F. (:5), respectively. The oil temperature in all instances was 180 F. (:5 At the end of each twenty-four hours under the abovedescribed cycling schedule, noise requirement determinations were made. After the noise requirement determinations were made, the engines were then put back on the cycling schedule for another twenty-four hours. The cycling and noise requirement tests were continued for nine 24-hour periods.

The noise requirement deter'minations were made according 'to three successive steps. If noise was encountered in step one, then steps two and threewere omitted. If noise was: encountered instep two, then only step three was omitted. Noise in this-test is intended to include preignition, normal knocking or rumble. The three successive stepsof the test'are as follows:

(1) At a. speed of 1100 rpm. the throttle is opened to detent (that is, the rear barrels of the carburetor are just open) at l-inch Hg intake manifold vacuum.

(2) The engine speed is increased to 1300 rpm. at 3- inch vacuum.

(3) The engine is acceleratedat IO-inch vacuum from. 1300 to 2000 r.p.m., standard spark, and held at this setting for 3 seconds (throttle Wide-open at end of 3-second period).

Aural observations are made at steps (1),. (2) and 3) and preignition, rumble and knock are recorded- Ratings are made on the tank fuel. (99 research octane number) and the actual noise requirement determined by the use of a set of commercial" reference fueis up to an octane number of 113.5. For noise requirements in the range 113.5 to 120, leaded isoootane was used. Octane numbers above 100 are expressed in the approved extension scale, \Mese octane numbers, which are:

Performance No.- 100 3 12 vert the lead to lead orthophosph'ate. The results of an additional (test are shown where 0.2 theories of triifmethoxyethyl) phosphate was used. The results of still further tests on fuel compositions containing an upper cylinder lubricant and a corrosion inhibitor are also shown.

Engine Fuel composition Base gasoline 111. 2 Base gasoline plus 0.2 theories of tri(butoxyethyl) phosphate (Example I composition) Base gasoline plus 0.3 theories of tri(butoxyethyl) phosphate (Example II composition) Base gasoline plus 0.4 theories of tri(butoxyethyl) phosphate (Example III composition) Base gasoline plus 0.3 theories of triOautoxyethyl) phosphate and 0.5 vol. erccnt Coastal Lubricating Oil Example V composition)" Base gasoline lus 0.2 theories of tri(methoxyet. yl) phosphate (Example VII composition)- Base gasoline plus 0.5 vol. percent Coastal Lubricating Oil and 5 pounds per 1,000 barrels of gasoline of the cocoamine salt of 3-methylbuiziyl 2-ethylhoxyl orthophosphorlc aci Base gasoline plus 0.3 theories of tri(butoxyethyl) phosphate, 0.5 vol. percent Coastal Lubricating Oil and 5 pounds per 1,000 barrels of gasolineof the cocoamine salt of 3-methylbutyl Z-ethylhexyl orthophosphoric acid (Example VI composition) The data in the foregoing Table I clearly indicate the improvement obtained when a small amount of rtri (butoxyethyl) phosphate is added to the base gasoline. It will be noted, for example, that the octane number requirement of the 10 to 1' compression ratio engines in which the base gasoline had been used was 120+. The octane number requirement of the 8.5 to 1 compression ratio'engine (Engine C) in which the base gasoline had been used was; 111.2. The octane number requirement when 'using fuel compositions of the invention was markedly reduced in every instance.

TABLE II.2=1-HOUR PERIODSCFO SUSTAINED VIOLENT C PREIGNITION Engine Fuel composition It will be noted from the data in Table II that test Engines A, B and D ran for five, three and two 24-hour periods, 'respectively,on the basegasoline before sustained violent preignitionwas'encountered. When the engines were operated with fuel compositions of the invention, sustained violent pre'ignition' was not encountered, with one exception, evenat the end of nine 24-hour periods.

The fuel compositions of the invention show not only marked improvement with respect to their preignition characteristics but also there are'less deposits formed in the combustion chambers of the engines operated with the improved fuels. At the termination of the prior tests,

TABLE TIL-DEPOSIT WEIGHTS (GRAMS) Engine Fuel composition Base gasoline Base gasoline plus 0.2 theories of tri(butoxyethyl) phosphate (Example I composition). Base gasoline plus 0.3 theories of tri(butoxyethyl) phosphate (Example II composition Base gasoline plus 0.4 theories of tri(butoxyethy)l) phosphate (Example III composition Base gasoline plus 0.3 theories of tri(butoxyethyl) phosphate and 0.5 vol. percent Coastal Lubricating Oil (Example V composition) Base gasoline plus 0.2 theories of tri(methoxyethsgl) phosphate (Example VII composition Base gasoline plus 0.5 vol. percent Coastal Lubricating Oil and pounds per 1.000 barrels of gasoline of the cocoamine salt of 3-methylbutyl 2-ethylhexyl orthophosphoric acid Base gasoline plus 0.3 theories of tri(butoxyethyl) phosphate, 0.5 vol. percent Coastal Lubricating Oil and 5 pounds per 1,000 barrels of gasoline of the cocoamine salt of 3- methylbutyl 2-ethylhexyl orthophosphoric acid (Example VI composition) The data in Table III clearly indicate that the deposits formed in the combustion chambers of each of the test engines was less when using a gasoline containing a tri- (alkoxyalkyl) phosphate than when using the base gasoline alone. While the addition of an upper cylinder lubricant gave an increase in deposits in some tests the deposits were still less than those obtained with the base gasoline alone.

In order to illustrate further the improved results obtained with fuel compositions of the invention, noise determinations were made in over-the-road fleet tests using four 1955 Cadillacs having a 10:1 compression ratio. Two of the cars were run for 6500 miles using as a fuel a base gasoline containing 0.2 theories of tri(butoxyethyl) phosphate (Example I composition). The other two cars were run for 10,000 miles using as a fuel a base gasoline containing 0.3 theories of tri(butoxyethyl) phosphate (Example II composition). Comparative tests were made on the same cars using the base gasoline alone. During the fleet tests, the cars operating on the fuel containing 0.2 theories of tri(butoxyethyl) phosphate were driven on a level driving course at a maximum speed of 35 mph for'the entire 6500 miles. The cars operating on the fuel containing 0.3 theories of tri(butoxyethyl) phosphate were driven on a level driving course at a maximum speed of 35 mph. for 6,000 miles, then over a hilly route at a maximum speed of 45 mph. for 2,000 miles and finally over the level course at a maximum speed of 35 mph for 2,000 miles. All of the cars were driven five days. a week, 7.5 hours per day. At the end of every third day of operation, noise requirement determinations were made on a dynamometer. As in the case of the multicylinder stationary engines the fleet cars were rated first on tank fuel and then the ,noise requirement determined by using commercial reference fuels. In the case of the fleet cars, requirements were determined first at 2500 r.p.m. and then at 2000 r.p.m. The noise requirements are expressed as octane numbers for either knock or rumble at 2500 r.p.m. When the cars were operated with the base gasoline, the/test at 35 mph. was discontinued after 3800 miles inasmuch as the octane requirement at the end of this period had become in excess of 120. The test was continued at 45 mph. for an additional 2000 miles at the end of which period the octane requirement leveled off at about 114. The cars operating on the fuel containing 0.2 theories. of tri(butoxyethyl) phosphate had average octane requirements of about 99-100 during the entire 6,500 miles. The cars operating on the fuel containing 0.3 theories of tri(butoxyethyl) phosphate vhad average octane requirements of about 97 to 98 over the entire test. The results obtained with the fuel of the invention are thus in marked contrast with the results obtained when using the base gasoline.

and of the cocoamine salt of isoamyl -octyl acid phosphate in addition to exhibiting improved noise .characteristics, i.e., less preignition, knock and rumble, also show improved anti-stalling characteristics. For example, when the composition of Example VI containing approximately atmospheric conditions, the number of engine stalls due to carburetor icing was markedly less for this composition than for an otherwise identical composition but containing no tri(butoxyethyl) phosphate.

The improved anti-stalling characteristics were determined in a 1954 Plymouth operating with an intake air temperature of 35 to 40 F., and a relative humidity of percent. In making the determinations, the engine was cold when started. The engine then was accelerated and maintained at 1500 r.p.m. for 1 minute after which the engine was decelerated to idle for /2 minute. At this time the stalling characteristics were observed and recorded. Ifthe engine stalled, the above cycle was repeated. -When the composition of Example VI was used as a fuel, there were 2 stalls in 11 cycles. When the comparative composition containing no tri(butoxyethyl) phosphate was used, there were 5 stalls in 13 cycles. Tn'(butoxyethyl) phosphate thus effected about a 50 percent reduction in the number of stalls.

The increased valve life imparted to engines operating with a fuel of the invention has been determined with a Chevrolet-6 engine. Inmaking this determination, the engine is operated on a cycling schedule consisting of 45 minutes at 3150 r.p.m. at a 30 horsepower load, 10 min-. utes at 3150 r.p.m. at a 60 horsepower load and then 5 valves fail. The results of the valve life tests are sum-.- marized in Table IV.

TABLE IV.VALVE LIFE TESTS Valve life in hours as measured by- Fuel composition r 1st 2nd, 3rd

failure failure failure Base gasoline plus 0.5 vol. percent Coastal Lubricating Oil and 5pounds per 1,000 barrels of gasoline of the cocoamine salt of 3-methylbutyl 2-ethylhexyl orthophosphoric acid 66 99 99 Base gasoline plus 0.3 theories of tri(butoxyethyl) phosphate, 0.5,,vol. percent Coastal. Lubricating'Oil and.5 pounds per 1,000 barrels of gasoline of the-cocoamine salt of 3- -methylbutyl 2-ethylhexyl orthophosphoric acid (Example VI composition) 253 -310 374 Thedata in Table. IV clearly indicate, the increased valve life obtained when operating an engine with a composition of the invention as compared with the base gaso- The fuel compositions of the present invention when 1 containing a small amount of upper cylinder lubricant line.. It will be noted, for example, that when the engine was operated with a fuel of the invention (Example VI composition) under the severe test conditions, the third valve failure did not occur until 374 hours. When the comparative composition. containing no tri(butoxyethy1) phosphate was used, the third valve failed within 99 hours. The tri(butoxyethyl) phosphate thus eifected about a 275 percent increase in valve life.

While our invention is described above with reference to various specific examples and embodiments, it will be understood that the invention is not limited to such examples and embodiments and may be variously practiced within the scope of the claims hereinafter made.

We claim:

1. A gasoline motor fuel comprising a major amount of gasoline containing tetraethyl lead in an amount sufficient to produce a gasoline fuel composition having a motor octane number of at least about 85 and a research octane number of at least about 95 and between about 0.1 and about 1.0 times the theoretical amount of a tri (alkoxyalkyl) phosphate required to convert the lead to lead phosphate, said tri(alkoxyalkyl) phosphate having the structural formula:

wherein R, R and R" are alkyl groups containing about 1 to about carbon atoms, R and R are selected from the group consisting of hydrogen and alkyl groups containing about 1 to about 3 carbon atoms and x is an integer from 1 to 2.

2. Agasoline motor fuel comprising a major amount of gasoline containing tetraethyl lead in an amount sutficient to produce a gasoline fuel composition having a motor octane number of at least'about 85 and a research octane number of at leastabout 95 and between about 0.003 and about 0.45 percent by weight, based on the gasoline, of a tri(alkoxyalkyl) phosphate having the structural formula:

R-(O-CHCHhO wherein R, R and R" are alkyl groups c'ontainingabout 1 to about 10 carbon atoms, R and R 'are selected from the group consisting of hydrogen and alkyl groups containing about 1 to about 3 carbon atoms and x is an integer from 1 to 2, the amount of the tri(alkoxyalkyl) phosphate present corresponding to at least 0.1 times the theoretical amount required to con'vert the lead to lead phosphate.

3. The motor fuel. composition of claim 2, wherein the sum of the carbon atoms in R, R and R" is at least 8 and R and R are hydrogen.

4. A gasoline motor fuel comprising a major amount of gasoline containing tetraethyl leadin an amount sulfieient to produce a gasoline fuel composition having a motor octane number of at least about 85 and a research octane number of at least about 95 and between about 0.0047 and about 0.14 percent by weight, based on the gasoline, of tri(butoxyethyl) phosphate, the amount of the tri(butoxyethyl) phosphate corresponding to at least about 0.1 times the theoretical amount required to convert the lead'to lead phosphate.

5. A gasoline motor fuel comprising a major amount of gasoline containing about 1 to about 3 cubic centimeters of tetraethyl lead per gallon of gasoline to produce a gasoline fuel composition having a motor octane number of at least about and research octane number of at least about and between about 0.1 and about 1.0 times the theoretical amount of tri (butoxyethyl) phosphate required to convert the lead to lead phosphate.

6. A gasoline motor fuel comprising a major amount of gasoline containing about 1 to about 3 cubic centimeters of tetraethyl lead per gallon of gasoline to produce a gasoline fuel composition having a motor octane number of at least about 85 and a research octane number of at least about 95, between about 00047 and about 0.14 percent by weight of tri(butoxyethyl) phosphate, the tri(butoxyethyl) phosphate comprising at least about 0.1 times the theoretical amount required to convert the lead in said tetraethyl lead to lead phosphate and about 0.25 to about 0.75 percent by volume of a light lubricating distillate oil having a viscosity at F. of from about 50 to about 500 Saybolt Universal seconds.

7. A gasoline motor fuel comprising a major amount of gasoline containing about 1 to about 3 cubic centimeters of tetraethyl lead per gallon of gasoline to produce a gasoline fuel composition having a motor octane number of at least about 85 and a research octane number of at least about 95, between about 0.0047 and about 0.14 percent by weight of tri(butoxyethyl) phosphate, the tri(buto)ryethyl) phosphate comprising at least about 0.1 times the theoretical amount required to convert the lead in said tetraethyl lead to lead phosphate, about 0.25 to about 0.75 percent by volume of a light lubricating distillate oil having a viscosity at 100 F. of from about 50 to about 500 Saybolt Universal seconds I and about 0.002 to about 0.008 .percent by weight of the 0.1 times the theoretical amount required to convert the lead in said tetraethyl lead to lead phosphate, about 0.25 to about 0.75 percent by volume of a light lubricating distillate oil having a viscosity at 100 F. of from about 50 to about 500 Saybolt Universal seconds, about 0.002 to about 0.008 percent by weight of the cocoamine salt of isoamyl octyl acid phosphate, about 0.001 to about 0.02 percent by weight of 2,6-di-tertiary-butyl-4- methylphenol and about 0.0003 to about 0.001 percent by weight of N,N-disalicylidene-l:Z-diaminopropane.

9. A gasoline motor fuel comprising a major amount of gasoline containing about 3 cubic centimeters of tetraethyl lead per gallon of gasoline to produce a gasoline fuel composition having a motor octane number of about 89 and a research octane number of about 99, about 0.043 percent by weight of tri(butoxyethyl) phosphate, the tri(bu toxyethyl) phosphate comprising abfout 0.3 times the theoretical amount required to convert the lead in said tetraethyl lead to lead phosphate, about 0.5 percent by volume of a light lubricating distillate oil having a viscosity at 100 F. of about 100 Saybolt Universal seconds, about 0.002 to about 0.006 percent by weight of the cocoamine salt of isoamyl octyl acid phosphate, about 0.007 percent by weight of.2,6-di-tertiary-butyl-4-methylphenol and about 0.004 percent by weight of N,N'-disalicylidene-l Z-diaminoprop ane.

10. A gasoline benefiting concentrate comprising a major amount of tetraethyl lead and about 0.1 to about 1.0 times the theoretical amount of a tri(alkoxyalkyl) phosphate required to convert the lead to lead phosphate,

wherein R, R and R" are alkyl groups containing about 1 to about 10 carbon atoms, R and R are selected from the group consisting of hydrogen and alkyl groups containing about 1 to about 3 carbon atoms and x is an integer from 1 to 2.

11. A gasoline benefiting concentrate consisting essentially of about 23 to about 60 percent by weight of tetraethyl lead, about 13 to about 36 percent by Weight of a mixture of ethylene halides and about 3 to about 63 percent by weight of a tri(butoxyethyl) phosphate, the tri(butoxyethyl) phosphate being present in at least 0.1

times the theoretical amount required to convert the lead in said tetraethyl lead to lead phosphate.

References Cited in the tile of this patent UNITED STATES PATENTS 2,372,244 Adams et a1 Mar. 27, 1945 2,405,560 Campbell Aug. 13, 1946 2,427,173 Withrow Sept. 9, 1947 2,477,220 V011 et a1. July 26, 1949 2,667,234 Hasche Jan. 26, 1954 2,723,237 Ferrin Nov. 8, 1955 2,794,719 Bartleson June 4, 1957 2,797,153 Bereslavsky June 25, 1957 2,820,766 Elliott et al. Jan. 21, 1958 2,851,343 Cantrell et a1 Sept. 9, 1958 FOREIGN PATENTS 600,191 Great Britain Apr. 2, 1948 683,405 Great Britain Nov. 26, 1952 733,820 Great Britain July 20, 1955 1,100,185 France Sept. 16, 1955 UNITED STATES PATENT'OFFICE CERTIFICATE OF CORRECTION Patent No. 3 009 790 I 7 November .21 1961 John Pv Pellegrini Jr at al,

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 7,, line 29 for "in" read me is g column 14 line 19 for "cumbustion" read combustion 3 column 16 line YO for "0.004"- read 0.0004

Signed and sealed this 10th day of April 1962..

(SEAL) Attest:

ERNEST in SWIDER DAVID L. LADD Attesting Officer Commissioner of Patents

Claims

6. A GASLINE MOTOR FUEL COMPRISING A MAJOR AMOUNT OF GASOLINE CONTAINING ABOUT 1 TO ABOUT 3 CUBIC CENTIMETERS OF TETRAETHYL LEAD PER GALLON OF GASOLINE TO PRODUCE A GASOLINE FUEL COMPOSITION HAVING A MOTOR OCTANE NUMBER OF AT LEAST ABOUT 85 AND A RESEARCH OCTANE NUMBER OF AT LEAST 95, BETWEEN ABOUT 0.0047 AND ABOUT 0.14 PERCENT BY WEIGHT OF TRI(BUTOXYETHYL) PHOSPHATE, THE TRI(BUTOXYETHYL) PHOSPHATE COMPRISING AT LEAST ABOUT 0.1 TIMES THE THEORETICAL REQUIRED TO COVERED TO CONVERT THE LEAD IN SAID TETRAETHYL LEAD TO LEAD PHOSPHATE AND ABOUT 0.25 TO ABOUT 0.75 PERCENT BY VOLUME OF LIGHT LUBRICATING DISTILLATE OIL HAVING A VISCOSITY AT 100*F. OF FROM ABOUT 50 TO ABOUT 500 SAYBOLT UNIVERSAL SECONDS.