US 3030195 A
Description (OCR text may contain errors)
" 3,030,195 Patented Apr. 17, 1962 3,030,195 MOTOR FUELS Evan B. Ewan, Swedesboro, N.J., assignor to Sun Oil Company, Philadelphia, Pa., a corporation of New Jersey No Drawing. Filed Jan. 20, 1959, Ser. No. 787,831 Claims. (Cl. 44-56) This invention relates to novel fuel compositions for spark ignition internal combustion engines. More particularly, it relates to a novel additive combination for the suppression of knocking or detonation during the combustion of such fuels.
The incorporation of various organo-metallic compounds in motor fuels to suppress knock has been prac ticed for some time. Organo-lead compounds have been found to be very effective, particularly tetraethyl lead (TEL), which is in common commercial use today. Recently another class of organo-metallic compounds, viz., cyclomatic manganese tricarbonyls, has been proposed as anti-knock additives. In the latter class methyl cyclo pentadienyl manganese tricarbonyl has been found to be particularly effective. The cyclomatic manganese tricarbonyls are quite compatible with TEL and thus can be used either with TEL or alone.
Many nonmetallic organic compounds have also been proposed and tested for anti-knock effectiveness, but none has been found to be as commercially practical as the organo-metallic lead compounds. The lower molecular weight aliphatic alcohols, for example, exhibit significant anti-knock effectiveness and possess other properties which recommend their use as motor fuel additives. As compared to TEL, for example, they are more volatile, less expensive, are more soluble in petroleum hydrocarbons and do not decompose to form harmful combustion chamber deposits. While their anti-knock effectiveness in unleaded fuel may not warrant their use alone as additives in fuels of low anti-knock quality, it would be highly desirable to use one or more lower aliphatic alcohol as a supplement to an organo-lead compound such as TEL, so as to permit either the use of lower anti-knock quality base fuels, or the replacement with the alcohol of a significant portion of the organo-lead compound with the consequent advantages described above. Unfortunately, however, when an organo-lead compound and a lower aliphatic alcohol are present together in gasoline, the anti-knock effect achieved by such a combination is substantially less than would be expected in view of their known individual anti-knock efiicacies. This phenomenon is well known in the art, and the lower aliphatic alcohols are often referred to as having negative lead susceptibilities, i.e., the property of reducing the anti-knock effect obtainable from the organo-lead compound. The same phenomenon may also be expressed in another Way, viz., that the octane number blending value, or apparent octane number, of the lower aliphatic alcohol is drastically reduced in the presence of organo-lead compounds. The latter terminology is generally preferred when speaking of motor fuel components present in the fuel in relatively substantial amounts rather than additives of very low concentration. Accordingly, the terminology of octane number blending value is generally used hereinafter.
In view of the above, one object of this invention is to produce novel motor fuel compositions wherein high antiknock quality is provided by a novel combination of additives, which fuels possess significant advantages over those containing anti-knock additives and combinations thereof heretofore described in the art. Another object is to provide a novel motor fuel anti-knock additive com bination containing both an organo-lead anti-knock compound and a lower aliphatic alcohol, in which the antiknock effectiveness of the lower aliphatic alcohols is substantially and unexpectedly enhanced. Other objects and benefits of the invention will become apparent'from a reading of the following detailed description of the invention.
It has now been discovered that in the presence of even a very small amount of a cyclomatic manganese tricarbonyl the anti-knock effectiveness of the lower aliphatic alcohols in motor fuels is not deleteriously affected by the presence of an organo-lead compound but, on the" contrary, is actually and unexpectedly improved to a substantial degree. Furthermore, in the presence of both the organo-manganese compound and an organo-lead anti-knock additives.
manganese compound, or in combination with the organolead compound. This synergistic effect is best illustrated by the experimental data presented in the following These data show the effect of various lower aliphatic alcohols on the anti-knock quality of a commercial grade motor fuel when used alone, and in combination; with TEL and/or methylcyclopentadienyl manganese t'ri-- In the table, the anti-knock quality of the} different motor fuels is expressed in terms of the octane: number obtained by the Research Method (A.S.T.M.
D908). As discussed hereinbefore, this invention resides in the synergistically high anti-knock quality of motor' fuel compositions containing the alcohol as a motor fuel blending component when both TEL and a cyclomatic The anti-knock" quality of the alcohols in the various motor fuel compositions represented in the following table is expressed inmanganese tricarbonyl are also present.
terms of the octane number blending value of the alcohol as a fuel component. By octane number blending value (O.N.B.V.) is meant the effective, or apparent, Research octane number of the alcohol. The O.N.B.V. is obtained by mathematical calculation from the volumetric composition of the final fuel blend (neglecting the volume ofadditives present in very small quantities such as TEL and methylcyclopentadienyl manganese tricarbonyl) and from the Research octane numbers of the motor fuel before and after addition of the alcohol. For example, in a motor fuel which had its Research octane number (R.O.N.) raised from 82.65 to 86.25 by the addition of 5.0 volume percent of methanol, the methanol in the final fuel blend would have an O.N.B.V. of
a d a TABLE ctane-Number Blending Values of Lower-- Aliphatic Alcohols With vol. percent With 5 vol. percent With 5 vol. percent With 5 vol. percent With 5 vol. percent methanol ethanol 2-propauol l-butanol 2-methyl-2-propanol R.O.N
O.N. O.N. O.N. O.N. O.N. R.O.N. B.V. of R.O.N. B.V. oi R.O.N. B.V. of R.O.N. B.V. of R.O.N. B.V. of Alcohol Alcohol Alcohol Alcohol Alchool l A. Base 1161 82. 65 86. 25 155 86. 55 161 85. 95 149 84. 25 115 83. 95 09 B. Base fuel+3 cc. TEL 96. 45 99.00 147 98. 70 141 98.10 129 96.85 104 97. 35 114 0. Base fuel+2.0 g. Mn 100. 55 103.30 156 102.85 147 103.05 151 101.95 129 101.50 120 D. Base fuel+2.0 g. Mn +3 TEL 105.70 111.25 217 111.80 228 111.25 217 106. 50 122 106.60 124 Basis: 1 gallon. 1 As methylcyclopentadienyl manganese tricarbonyl.
As can be seen from the above data, the lower molecular Weight aliphatic alcohols, vizl, methanol, ethanol and 2- propanol, have unexpectedly high octane number blending values when used in combination with TEL and methylcyclopentadienyl manganese tricarbonyl. The other aliphatic alcohols shown, viz., l-butanol and 2- methyl-2-propanol, do not exhibit similar synergism and are.therefore not within the scope of this invention.
In accordance with the practice of this invention, one or more lower molecular weight aliphatic alcohol is employedas a motor fuel additive in combination with an organo-lead' anti-knock compound and a cyclomatie manganese: tricarbonyl. Suitable alcohols for use are theprimary and secondary alcohols having not-more than 3. carbon atoms per molecule. Alcohols which can be employed are methanol, ethanol, 1-propanol, and 2-propanol. The use of methanol in'the practice of this invention is preferred. Preferably, the alcohol employed should be anhydrous, but alcohols containing small amountsof water can be used with good results. Generally, amounts of the alcohol in the range of from about 0.5% to about 15.0% by volume of the resultant fuel composition are suitable although, on occasion, amounts outside of this range can also be employed. Concentrations of the alcohol of from about 1.0% to about 10.0% by volume give excellent results and are preferred. Within the preferred concentration range most of the lower aliphatic alcohols are. completely miscible with petroleum hydrocarbons audit is preferred that the alcoholbe usedin an amount within its solubility limits in the fuel. However, if desirable, an amount of the alcoholin excess of its solubility can be incorporated in the fuel by such means, as for example, mutualsolvents or dispersants. I
The novel fuel compositions of the invention must contain an organo-lead anti-knock compound and a cyclomatic manganese tricarbonyl. Tetraethyl lead (TEL) is themost commonly used organo-lead anti-knock compoundand is preferredlin the practice of the present invention. However, other organo-lead compounds such as, forexample, .tetramethyl lead, tetraphenyl lead, tetrai-propyl lead, triethyl methyl lead, diethyl dimethyl lead, and-tetraamyl lead also give good results. Mixtures of these compounds can. also be used in practicing this invention. In automotive motor fuels the organo-lead antiknock compounds can be used in amounts ranging from about 0.05 to 3 cc. of the compound per gallon of fuel,v while in aviation fuels a greater amount can be used, viz., up to about 6 cc. per gallon. The upper limits in the above recited concentration ranges are consistent with current industry practice'as to the maximum amount of sii'cli compounds to be employed. However, it is to be understood that the present invention is not to be limited thereby, since excellent results are also obtained in the practice of this invention with amounts greater than the above upperlimit's; ln accordance with one of the principal objects of the invention,.it is desirable to use assmall' an amount of the organo-lead anti-knock additive as is practical. It has been found, for example, that good? results can be achieved with the use of amounts as small as 0.05 cc. per gallon.
Along, with the organo-lead anti-knock compound,
various volatile halohydrocarbons are normally incorporated in the fuel in lead scavenging amounts, i.e., in
amounts theoretically calculated to convert the lead in the organo-lead' compound to volatile compounds, viz.,
lead dihalides. Examples of such halohydrocarbon lead scavengers are: organo-bromides and-chlorides suchas ethylene dib'romide, ethylene dichloride, acetylene tetrabromide, hexachloropropylene, and mixtures thereof; monoand poly-halo-propanes, -butanesand -pentanes;
polyhalo-alkyl be'nzenes; and mixtures thereof with each other and the like. It is to be understood that this invention contemplates the use, together with theiorgano-lead anti-knock compound, of all such lead scavengers as are commonly employed, and'in such amounts as may be" 40, required.
One or more cyclomatic manganese tricarbonyl antiknock additives must also be present'in the fuel compositions of this invention. The oyclomatic manganese tricarbonyls have the general formula:
AMn(CO) wherein A is a cyclornatic hydrocarbon radical. As used herein the term cyclomatic radical'is intended to denote a carbocyclic radical having 5 or more carbon 0 atoms and embodying the configurationcharacteristic of' cyclopentadiene. Four different types of cyclomatic hydrocarbon radicals are suitable for use, these being represented by the following generic structural formulae:
(1) The cyclopentadienyl-type radical (2) The indenyltype radical n." was R- l a.
(3) The fiuor'enyl type radical wil ( 2M (CH2)b wherein a and b can be the same or different and are either zero or small whole integers excluding 1. The symbol R, as designated by various subscripts in the foregoing formulae, can be the same or different and represents either hydrogen or a monovalent hydrocarbon substituent. The hydrocarbon substituents can be either aliphatic, alicyclic or aromatic radicals and preferably contain not more than 12 carbon atoms per radical. Thus, the cyclomatic hydrocarbon radicals can contain such substituents as, for example, alkyl, alkenyl, aralkyl, aralkenyl, cycloalkyl, cycloalkenyl, aryl and alkaryl groups. Illustrative, but nonlimiting examples of such substituted and unsubstituted cyclomatic manganese tricarbonyl anti-knock compounds are: cyclopentadienyl manganese tricarbonyl; methylcyclopentadienyl manganese tricarbonyl; benzylcyclopentadienyl manganese tricarbonyl; 1,2-dipropyl-3-cyclohexylcyclopentadienyl manganese tricarbonyl; 1,3-diphenylcyclopentadienyl manganese tricarbonyl; idenyl manganese tricarbonyl; 3-(A- propenyl)indenyl manganese tricarbonyl; Z-(a-phenylethenyl)indenyl manganese tricarbonyl; 3-(oc-CYCl0l16XYlethenyl)indenyl manganese tricarbonyl; 2-tolylindenyl manganese tricarbonyl; fluorenyl manganese tricarbonyl; 2,3,4,7-tetrapropylfluorenyl manganese tricarbonyl; 3-(ocphenylethyDfiuorenyl manganese tricarbonyl; 4-cyclopropylfluorenyl manganese tricarbonyl; B-naphthylfiuorenyl manganese tricarbonyl; 4,5,6,7-tetrahydroindenyl manganese tricarbonyl; 3-ethenyl-4,7-dihydroindenyl manganese tricarbonyl; 2-ethyl-3-(a-phenylethe-nyl)-4,5,6,7- tetrahydroindenyl manganese tricarbonyl; 3- (a-CYClOhCXYlethenyl)-4,7-dihydroindenyl manganese tricarbonyl; 3- tolyl-4,5,6,7-tetrahydroindenyl manganese tricarbonyl; 1,4,5,8-tetrahydrofluorenyl m a n g a n e s e tricarbonyl; 1,2,3,4,5,6,7,8-octahydrofluoreny1 manganese tricarbonyl and the like. Mixtures of such compounds can also be used. The cyclomatic manganese tricarbonyl anti-knock compounds can be prepared by methods which are known in the art. Preparation methods are described, for example, in U.S. Patents 2,818,416 and 2,818,417.
Only a very small amount of this organo-manganese compound is required to achieve the synergistically high anti-knock effectiveness of the alcohol present and, in accordance with the principal object of the invention, it is desirable to use as little of the organo-manganese compound as is necessary to obtain the benefits of the invention. Concentrations of the cyclomatic manganese tricarbonyl compound (expressed as grams of manganese metal per gallon of the resulting fuel composition) as low as 0.02 g. per gallon are sufficient, but concentrations up to and including 10.0 g. per gallon can be employed. On occasion, amounts outside of the aboverecited range can be employed. Concentrations in the range of from about 0.1 g. to about 3.0 g. per gal. give excellent results and are preferred. It is to be understood that this invention contemplates the use of other additives, such as scavengers, made necessary or desirable by the presence of the organo-manganese compound in the fuel.
The novel spark-ignition engine fuel compositions of this invention comprise mainly gasoline, i.e., fractions of petroleum hydrocarbons boiling (at atmospheric pres sure) in the gasoline boiling range of from about 80 F. to about 440 F., and usually from about 90 F. to about 400 F. Both automotive gasoline and aviation gasoline are within the scope of this invention. Aviation gasoline has a more closely specified atmospheric boiling range, generally extending from a minimum of about 100 F. to a maximum of about 350 F. The fuel com- 6 positions of the invention can contain, in addition to the novel additive combination described herein, any other fuel additives commonly employed in the art such as, for example, anti-icing agents, detergents, corrosion inhibitors, stabilizers, dyes, and the like.
Fractions of petroleum hydrocarbons boiling within the gasoline range generally contain various hydrocarbon types such as, for example, saturated (including straight and branched chain aliphatic and cyclic) hydrocarbons, olefins and aromatics. While blends of these hydrocarbon types in any and all proportions are suitable for use as the base fuel to which is added the novel additive combination in accordance with the present invention, it has been found that the results achieved are more beneficial the greater the proportion of saturated hydrocarbons and the lower the proportion of aromatics and olefins in the base fuel blend. For example, gasolines containing not less than about 50.0 vol. percent of saturated hydrocarbons and not more than about 50.0 vol. percent total of olefins and aromatics are suitable for the practice of this invention and give good results. Gasolines containing even greater proportions of saturated hydrocarbons, viz., not less than about 70 vol. percent give better results and are preferred.
It is essential in the practice of this invention only that the novel combination of additives, viz., an organolead anti-knock compound, a cyclomatic manganese tricarbonyl and one or more suitable lower molecular weight aliphatic alcohol, be present in suitable amounts in the liquid fuel just prior to vaporization and combustion of the fuel in the engine. Accordingly, it is within the scope of this invention to add the components of the novel additive combination to the base fuel either separately in any sequence, or as a mixture or mixtures with each other, so long as the foregoing requirement is met. In one embodiment of the invention, for example, a mixture consisting of all of the components of the novel additive combination is separately prepared and subsequently blended with the base fuel either at the refinery or in the dispensing pump. When using such mixtures, it is desirable that the components be present in the relative proportions desired between suchcomponents in the final fuel composition, e.g., 0.05 to 6.0 parts by volume of tetraethyl lead anti-knock compound; 0.057 to 28.5 parts by volume of the compound methylcyclopentadienyl manganese tricarbonyl; and from 18.9'to 568.0 parts by volume of one or more suitable alcohol. Such mixtures can be incorporated in small amounts of gasoline to provide concentrates therein for ease in handling. Furthermore, any ancillary additives such as scavengers required by the organo-lead and organo-manganese compounds can also be present in the mixtures of components of the novel additive combination.
In order to illustrate a specific embodiment of the invention a novel fuel composition was prepared from a gasoline consisting of a predominant proportion of saturated hydrocarbons and minor proportions of olefins and aromatics. This gasoline, with 3 cc. of TEL and 2.0 g. Mn (as methylcyclopentadienyl manganese tricarbonyl) per gallon had a Research octane number of 99.7. To each of two portions of the above gasoline containing TEL and the organo-manganese compound methanol was added in an amount equivalent to 1.0 vol. percent in the first portion and 2.0 vol. percent in the second, both concentrations being based on the resultant fuel compositions. The two fuel compositions illustrate the novel compositions of the invention. The fuel containing the 1.0 vol. percent methanol had a Research octane number of 100.8, corresponding to a methanol octane number blending value of 215. The fuel containing the 2.0 vol. percent methanol had a Research octane number of 101.7, corresponding to a methanol octane number blending value of 200. It can readily be seen that when methanol is used in combination with TEL and methylcyclopentadienyl manganese tricarbonyl, it has an unexpectedly high a'nti knock quality as a motor fuel component.
When the other disclosed lower aliphatic alcohols, viz.,
ethanol, 1-propanol and 2-propanol, are used in accordance with the invention substantially equivalent results are obtained.
This application is-a' continuation-in-part of my pendin'g-application, Serial'Number 710,399, filed on January 22, 1958, and now abandoned.
The invention claimed is:
1. A- motor fuel composition for spark ignition internal combustion engines consisting essentially of: petroleum hydrocarbons boiling Within the gasoline range; a small, anti-knock amount of a tetra-alkyl lead anti-knock compound; a small, anti-knock amount of a cyclopentadienyl manganese tricarbonyl anti-knock compound having the general formula AMn(CO) wherein A is a radical selected from the group consisting of the unsubstituted cyclopentadienyl radical and hydrocarbon-substituted cyclopentadienyl radicals having less than 13 carbon atoms in each substituent hydrocarbon group; and from about 0.5 to about 15.0 volume percent of an alcohol selected from the group consisting of methanol, ethanol, l-propanol and 2-propan0l.
2. A fuel composition according to claim 1 wherein said tetra-alkyl lead anti-knock compound is tetraethyl lead and said cyclopentadienyl manganese tricarbonyl anti-knock compound is methylcyclopentadienyl manganese tricarbonyl.
3. A fuel composition according to claim 1 whereinsaid alcohol selected from the group is methanol.
4. A fuel composition according to claim 1 wherein said alcohol selected from the group is ethanol.
5. A fuel composition according to claim 1 wherein said alcohol selected from the group is l-propanol.
6. A fuel composition according to claim 1 wherein said alcohol selected from the group is 2-propanol.
7. A motor fuel composition for spark ignition in ternal combustion engines consisting essentially of: petroleum hydrocarbons boiling within the gasoline range; from about 0.5 to about 6.0 cc. per gallon of a tetra-alkyl lead anti-knock compound; from about 0.02 to about 10.0 grams per gallonrof manganese as a cyclopentadienyl manganese tricarbonyl anti-knock compound having the general formula AMn(CO) wherein A is a radical selected from the group consisting of the unsubstituted cyclopentadienyl radical and hydrocarbon-substituted cyclopentadienyl radicals having less than 13' carbon atoms in each substituent hydrocarbon group; and from about 0.5 to about 15.0 volume percent of an alcohol selected from the group consisting of methanol, ethanol, l-propanol and 2-propanol.
8. A fuel composition according to claim 7 wherein said tetra-alkyl lead anti-knock compound is tetraethyl lead and said cyclopentadienyl manganese tricarbonyl antiknock compound is methylcyclopentadienyl manganese tricarbonyl.
9. An anti-knock additive composition for incorporation in spark ignition internal combustion engine fuels which consists essentially of: from about 0.05 to about 6.0 parts by volume of a tetra-alkyl lead anti-knock compound; from about 0.057 to about 28.5 parts by vol ume of a cyclopentadienyl manganese tricarbonyl antiknock compound having the general formula AMn(CO) wherein A is a radical selected from the group consisting of the unsubstituted cyclopentadienyl radical and hydrocarbon-substituted cyclopentadienyl radicals having less than 13 carbon atoms in each substituent hydrocarbon group; and from about 18.9 to about 568.0 parts by volume of an alcohol selected from the group consisting of methanol, ethanol, 1-propanol and 2-propanol.
10. An additive composition according to claim 9 wherein said tetra-alkyl lead anti-knock compound is tetraethyl lead and said cyclopentadienyl manganese tricarbonyl anti-knock compound is methylcyclopentadienyl manganese tricarbonyl.
References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Aviation Gasoline Manufacture, Van Winkle, 1st Ed. 1944, McGraW-Hill Book (10., page 199.
A1cohola Fuel for Internal Combustion Engines, by Pleeth, Chapman & Hall Ltd., 1949, pages 120-129.