US2913413A

US2913413A - Compositions for engine operation

Info

Publication number: US2913413A
Application number: US683759A
Authority: US
Inventors: Jerome E Brown
Original assignee: Ethyl Corp
Current assignee: Ethyl Corp
Priority date: 1957-09-13
Filing date: 1957-09-13
Publication date: 1959-11-17
Anticipated expiration: 1976-11-17

Description

Nov. 17, 1959 Filed Sept. 13, 1957 J. E. BROWN COMPOSITIONS FOR ENGINE OPERATION FIGURE l 2 Sheets-Sheet 1 INVENTOR. JEVOME'EBROWN Nov. 17, 1959 J. BROWN 2,913,413

COMPOSITIONS FOR ENGINE OPERATION Filed Sept. 13, 1957 2 Sheets-Sheet 2 FIGURE 2 n: u..| tn 2 :3 z

L|.l 2 S u o w 2 7: u m o z T K L Y IOO Pb 50 Pb O Pb 0 Mn 50 Mn I00 Mn WEIGHT PER CENT OF TOTAL METAL INVENTOR JEROMEE BROWN an internal combustion engine.

United States COMPOSITIONS FOR ENGINE OPERATION Jerome E. Brown, Detroit, Mich., assignor to Ethyl Corporation, New York, N.Y., a corporation of Delaware This invention relates to a method of operating a spark ignition internal combustion engine which utilizes novel compositions of-matter containing a non-ionic metal polycarbonyl compound which enable an engine to give knock-free performance and which possess numerous benefits in connection with improved combustion characteristics and the alleviation of modern day engine problems. This application is a continuation-in-part of prior applications Serial No. 365,279, filed June 30, 1953 (now abandoned.) and Serial No. 446,181 filed July 27, 1954 (now abandoned), which in turn were continuations-inpart of prior application Serial No. 234,463, filed June 29, 1951 (now abandoned).

In the drawings accompanying this specification:

Figure 1 is a schematic representation of an embodiment of this invention and Figure 2 is a graphic representation of the beneficial effect obtained from the use of certain of the compositions of this invention.

Concurrent with the development of'the modern high eificiency, high compression ratio, internal combustion engine of the spark ignition type, it was necessary to develop fuels which would permit the knock-free operation required to utilize most effectively these advances in engine design. The approach to this problem has been in .two directions. On the one hand, improvements in refining operations have been undertaken to provide hydrocarbon fuels wherein the ingredients or mixtures thereof possess high antiknock quality. There exists, however, a limit, depending on a number of factors, beyond which the fuels cannot be economically improved. On the other hand, additives have been provided for such fuels whereby a further increase in the antiknock quality of the mixture is produced.

atent The most successful antiknock additive from a practical standpoint has been tetraethyllead. From time to time, a number of other antiknock materials have been proposed, but none of them have attained commercial Significance in this country.

It is an object of this invention to provide an improved method for operating an internal combustion engine. Another object is to provide new compositions of matter. A more specific 'object is to provide new gasoline compositions. It is also an object of this invention to provide a gasoline containing metal polycarbonyl antiknock compounds or mixtures of such compounds which possess greatly reduced wear causing characteristics. A still further object is to provide gasoline suitable for use in high efficiency, spark ignition internal combustion engines requiring a fuel of high antiknock quality. Still another object is to provide a lubricating oil which acts to reduce the octane requirement of Among the other objects of this invention is the alleviation of engine problems including octane requirement increase, spark plug fouling and surface ignition. Additional objects of the instant invention will be apparent from the discussion which follows:

The above and other objects of this invention are acice complished by providing a process for operating a spark ignition internal combustion engine which comprises introducing into the cylinders thereof, a non-ionicmanganese polycarbonyl antiknock agent. The objects of this invention are also accomplished by providing, ,as novel compositions of matter, gasoline, lubricating oil and antiknock fluids containing a non-ionic manganese polycarbonyl compound or mixtures of manganese polycarbonyl compounds as antiknock agents.

Thus among the important compositions contemplated by the present invention are included a hydrocarbon fuel of the gasoline boiling range for use in spark ignition internal combustion engines containing a small amount of manganese pentacarbonyl .sufficient to improve the antiknock properties of said hydrocarbon fuel. For most purposes this amount of manganese pentacarbonyl will range from about 0.01 gram to about 6 grams of manganese per gallon of fuel. In a preferred embodiment of the invention the amount of manganese pentacarbonyl is regulated so as to be from 0.2 gram to 4 grams of manganese per gallon. More specifically, the present invention contemplates a hydrocarbon of the gasoline boiling range for use in spark ignition internal combustion engines containing substantially 1.77 grams of m'anganese'in the form of manganese pentacarbonyl per gallon of fuel. The present invention also embraces the process of obtaining improved operating characteristics of a spark ignition internal combustion engine which comprises operating said engine on a fuel composition which consists of a hydrocarbon fuel of the gasoline boiling range containing a small amount of manganese pentacarbonyl suflicient to improve the antiknock properties of said hydrocarbon fuel.

It is essential that the manganese polycarbony-l compounds used in the practice of this invention be nonionic in nature in order that they produce the desired effect. For example, ionic manganese carbonyl compounds such as those having halogen bonded directly to manganese are not sufiiciently volatile to be readily inductible into the cylinders of a multi-cylinder engine using a manifold type intake valve. These compounds are unable to give the benefits attributable to non-ionic manganese polycarbonyl compounds.

An unexpected feature of this invention is that the non-ionic manganese polycarbonyls are among the most effective antiknock agents tested to date. This is particularly surprising when it is considered that manganese is located in the Periodic Table next to the element chromium. Chromium carbonyl exhibits a pro-knock effect when employed as a gasoline additive for use in a spark ignition internal combustion'engine.

Even when 'a compound has exceptional antiknock activity, the chances of its becoming a useful product remain extremely remote. This is due to the fact that many other properties must be taken into consideration before a new product can be seriously considered as a useful product. Thus, in the past, compounds having antiknock activity have been rejected from the commercialization because they (a) Have a deleterious effect on the operation of an engine (b) Are not sufficiently soluble in the fuel (0) Are not volatile enough for proper engine inductibility (d) Possess objectionable odors (e) Bring about excessive wear.

For example, various iron and nickel compounds including iron carbonyl and dicyclopentadienyl nickel have been suggested as antiknocks but have not been accepted due to the excessive engine wear caused by their use. As a further example, many aromatic amines exhibit quired of commercial additives.

antiknock acitivity, but their use is not feasible due to the fact that they exude a particularly objectionable odor.

Therefore, to be commercially successful, an antiknock must possess many auxiliary properties in addition to outstanding antiknock activity. Any compound under consideration must undergo extensive tests to insure that it meets the important secondary qualifications.

It has been found that the non-ionic manganese polycarbonyl compounds, which are the subject of the present invention, possess all the requirements of a successful antiknock to a remarkable degree. That is, they not only exhibit outstanding antiknock effectiveness, but in addition have the properties (including volatility, stability, gasoline solubility, lack of gum forming tendencies, minimization of engine deposits and engine wear and susceptibility to preparation from available materials) re- For example, manganese carbonyl causes only about one-fifth the wear caused by an equivalent amount of iron as iron carbonyl.

The fuels and lubricants used in todays high compression automotive engines cause deposits to be formed during combustion. These deposits which are derived from the fuels and lubricating oils and the additives therein collect on essentially all parts of the combustion chamber including the valves, the spark plugs and the cylinder Walls. The formation of these deposits leads to several problems such as octane requirement increase, deposit induced ignition and spark plug fouling. These problems prevent maximum utilization of the potential of a fuel and limit the designer from providing engines which will accomplish this end.

Not only do the non-ionic manganese polycarbonyl compounds exhibit the properties required of a successful antiknock, but they also have valuable and unexpected auxiliary effects on the operation of a spark ignition internal combustion engine. It has been found that these compounds minimize octane requirement increase and deposit induced ignition and increase the spark plug life of the modern high compression spark ignition internal combustion engine.

An important embodiment of this invention is gasoline containing, in amounts sufficient to improve the octane quality thereof, a non-ionic manganese polycarbonyl compound which is soluble in the gasoline. It has been found that non-ionic manganese polycarbonyl compounds are of outstanding effect as antiknock agents. The amount of the manganese polycarbonyl compound present in the compositions of this invention is regulated such that at least about 0.01 gram of manganese is present per gallon of the finished gasoline, and ordinarily up to about 6 grams of manganese per gallon is provided. In a preferred embodiment the amount of manganese polycarbonyl is regulated to provide from 0.2 gram to 4.0 grams of manganese per gallon of fuel.

The upper limit of beneficial use of the non-ionic manganese polycarbonyl compounds is, as a practical matter, limited due to the fact that at high concentrations the magnitude of the octane number benefit obtainable per unit weight of compound decreases to some extent. Thus, the most beneficial antiknock effect of the non- 'ionic manganese polycarbonyl compound is realized when these compounds are employed in concentrations 'such that there is from about 0.03 to about 10 grams of manganese per gallon of the finished gasoline. At higher concentrations the antiknock efiect per unit weight is diminished, and the other beneficial efiects are also reduced. When used as a primary additive, the best results are obtained when from about 0.01 to about 6 grams of manganese are present in the gasoline.

Spectacular results are obtained in the alleviation of CR1 (the octane requirement increase due to engine deposits) and surface ignition by the use of the manganese polycarbonyls. These deposit modifying effects are obtained both in the presence and absence of organolead antiknock agents. Drastic increases in spark plug life are also imparted by these compositions, particularly when the gasoline also contains at least 0.015 percent of sulfur. The sulfur can be either naturally-occurring sulfur or added sulfur in the form of gasoline-soluble organic compounds. In either case this sulfur is typically in the form of elemental sulfur, hydrogen sulfide, mcrcaptans, sulfides, thiophenes, disulfides, polysulfides and the like. The benefits of this invention are realized in either event.

An outstanding feature of the present invention which is of the greatest commercial importance is the unexpected discovery that the non-ionic manganese polycarbonyl compounds exhibit two distinct types of synergistic effects when used in conjunction with organolead antiknock agents. One of these eifects occurs at manganese concentrations of as low as 0.5 percent of the lead present in the fuel and consists of an increase in octane quality of the fuel of a completely unpredictable magnitude. The other synergistic eifect is achieved at higher manganese proportions and consists in realization of an octane quality much above that to be expected on the basis of determination with either component alone.

When small amounts of manganese as a non-ionic manganese polycarbonyl compound are used in con junction with from 1 to about 6 grams of lead per gallon as an organolead compound, a synergistic effect is obtained in terms of the increase in octane quality of the gasoline. This effect is realized at manganese concentrations up to about 15 percent of the total metal concentration of the fuel, and is observed at concentrations as low as 0.03 gram of manganese per gallon in fuels containing at least 1 gram of lead as an organolead-compound, such as tetraethyllead, per gallon.

The increase in octane number obtained by replacing a small amount of lead with an equal amount of manganese as a non-ionic manganese polycarbonyl compound is totally unexpected. That is, a great percentage of the increase which is obtainable from a complete replacement of lead with a non-ionic manganese polycarbonyl is realized with the first incremental amounts of the latter. Thus, a mixture of 95 percent lead and 5 percent manganese as a non-ionic manganese polycarbonyl compound affects as much as 50 percent of the improvement in octane quality which can be realized with a complete replacement of lead with such a compound.

This phenomenon can be more readily appreciated by reference to Figure 2 which is a graphical representation of the change which occurs in the antiknock quality of a fuel having 3 grams of metal per gallon in the form of a pure organolead compound, a pure manganese polycarbonyl compound or appropriate mixtures of these. The ordinate expresses the octane quality of the gasoline in terms of octane number while the abscissa indicates the mixture of antiknoclr agents which produces this octane number. If the gasoline having 3 grams of lead as tetraethyllead has the octane number indicated by point I of Figure 2 and a higher octane number as shown on point I of the figure when it contains 3 grams of manganese as a non-ionic manganese polycarbonyl, it would be expected that any intermediate compositions comprising a mixture of organolead and non-ionic manganese polycarbonyl antiknock agents would give a resulting fuel having the octane quality rating indicated by the dash line II. However, as illustrated by the point K in Figure 2, addition of a minute quantity of a non-ionic manganese polycarbonyl compound to the leaded fuel gives the fuel an octane rating sharply above the predicted value. The actual octane number enhancement achieved by addition of a minute amount of non-ionic manganese polycarbonyl to a leaded fuel ranges up to several hundred percent of the predicted value.

In general the outstanding synergistic results are realized with compositions whose antiknock constituent contains between about 5 and 10 percent manganese and to 95, percent lead when th total metal concentration is 1 gram per gallon. At the higher total metal concentrations the synergism is evidenced by a somewhat wider range of compositions. Thus, when the total metal concentration is 2 grams per gallon the synergism is realized by utilizing compositions which contain from 2 to about 13 percent of manganese, the balance being lead. When the total metal concentration is about 3 grams per gallon the synergistic effect is realized with from about 1 to about 15 percent manganese. At still higher concentrations the synergism is realized when the proportions of manganese in the antiknock agent is as low as 0.5 percent.

The magnitude of the above described effect varies somewhat depending upon the nature of the gasoline. However, in general the most significant advance in octane number with increased manganese concentrations is in the range between 2 and percent manganese based on the amount of Pb present. These concentrations are found to give about one-half the effect realized from the conversion from lead to a non-ionic manganese polycarbonyl. Thus, when a small amount (from about 2 to about 10 percent) of a non-ionic manganese polycarbonyl compound is used in conjunction with an organolead antiknock agent, a very significant increase in octane quality is obtained which would not be predicted by a comparison of the relative eifect obtainable from an organolead antiknock and a non-ionic manganese polycarbonyl compound.

Even at higher concentrations a manganese polycarbonyl compound in admixture with an organolead compound produces an increase in the octane rating of a gasoline which cannot be accounted for by virtue of the organolead compound and the manganese polycarbonyl compound additively. This elfect is observed when at least 1 gram of manganese as a non-ionic manganese polycarbonyl is employed. Thus, an embodiment of this invention is an improved gasoline containing a synergistic mixture of at least 1 gram per gallon of manganese as a manganese polycarbonyl compound in admixture with an organolead compound. Generally, the amount of such organolead compound is sufiicient to give a lead concentration of from about 0.5 to about 8 grams per gallon.

Such a synergism is illustrated by a mixture of manganese carbonyl and tetraethyllead. When tested alone in a commercial gasoline, manganese carbonyl is found to be 1.9 times as effective as tetraethyllead on a Weight of metal basis. Thus, a fuel containing 1 gram of manganese as manganese carbonyl and 1 gram of lead as tetraethyllead would be expected to give the same octane number as a fuel containing 2.9 grams of lead as tetraethyllead. However, such a mixture gave an octane number increase which would only be realized with the addition of 3.8 grams of lead. Therefore, the addition of 1 gram of manganese as manganese carbonyl gave about twice its expected effect.

It has also been found that when a manganese polycarbonyl compound is added to the crankcase lubricating oil of an internal combustion engine, a drastic and rapid decrease in the octane requirement of the engine takes place. This is believed to be due to the fact that the manganese polycarbonyl compound enters the cylinders of the engine either as a vapor or in the oil film on the cylinder walls. Thus, the objects of this invention are also accomplished by providing a lubricating oil for internal combustion engines, which oil contains a manganese polycarbonyl compound in amount suflicient to reduce the octane requirement of the fuel used in the engine.

As the non-ionic manganese polycarbonyl compounds find outstanding and unexpected utility as additivesto both gasoline and crankcase lubricating oil, this invention gives rise to novel compositions of matter comprising a liquid hydrocarbon mixture useful in a spark ignition internal combustion engine, which mixture contains a non-ionic manganese polycarbonyl compound in amount sufiicient to improve the combustion characteristics of the engine.

The non-ionic manganese polycarbonyl antiknock agents of this invention are also conveniently introduced into the cylinders of an internal combustion engine by utilizing a separate system of supply in conjunction with the system which supplies fuel to the cylinders. Thus, the non-ionic manganese polycarbonyl compounds are supplied to the cylinders by atomiz ing, vaporizing or directly spraying the compound or a solution thereof, directly into the cylinders or into the intake manifold which supplies the cylinders with fuel. Introduction of the non-ionic manganese polycarbonyl compound into the manifolding system may be accomplished either prior or subsequent to carburetion or injection of the gasoline. When the non-ionic manganese polycarbonyl compound is a solid, it is often possible to vaporize it by passing a stream of air over or through a supply of the compound. When the compound is a liquid, it is conveniently supplied to the intake manifold through a wick which is supplied from a reservoir of the liquid.

Figure 1 is illustrative of a method of introducing a non-ionic manganese polycarbonyl compound into a combustion chamber of an internal combustion engine having a plurality of combustion chambers equipped with movable pistons wherein the walls of the chambers are lubricated with a crankcase lubricating oil and wherein gasow line is introduced into the combustion chamber and ig-' nited and the products of combustion act upon the pistons and produce a driving force. With reference to Figure 1, the numeral 10 generally represents a cylinder and cylinder head of a multi-cylinder spark ignition internal combustion engine which contains a piston 11, combustion chamber 12, spark plug 13 which is under the influence of an ignition system (not shown), intake valve 14 and intake port 15 through which gasoline and combustion air are supplied by a carburetion system (not shown), an exhaust valve 16 and an exhaust port 17. These components make up the basic parts required in a conventional four-cycle spark ignition internal combus tion engine. I

To eflectively conduct the process ofthis invention, a non-ionic manganese polycarbonyl compound is conveniently injected into the combustion chamber 12 by the utilization of a separate injection system which consists of a supplemental opening 18 which has fitted theretoa valve 19 shown for purposes of illustration as a poppet valve held closed by a spring 20 and having an elongated stem 21 which places the valve under the influence of a solenoid 22. The solenoid 22 is conveniently arranged to be under the influenceof a set of breaker points (not shown) coordinated with the ignition system of the engine so that the valve 19 will be open during the intake stroke of the piston 11 for a time sufi'icient to permit the required amount of non-ionic manganese polycarbonyl compound to enter the combustion chamber 12. The non-ionic manganese polycarbonyl compound is supplied through the opening 18 by means of avaporizing system 23 which terminates in an inlet port 24 through which the valve stem 21 operates by means of the aperture 25. The valve stem 21 is sealed in the aperture 25 in any convenient manner. To supply a non-ionic manganese polycarbonyl compound as a vapor to the combustion chamber 12 through the opening 18, a reservoir 26 of any convenient form contains a supply of manganese polycarbonyl compound to a convenient level 27. The container 26 is fitted with a means for passing vaporizing gas through the manganese polycarbonyl compound as shown by the conduit 28 which is attached to an opening 29 in the container 26. Back-up in the conduit 28 is prevented by any convenient means, such as a diaphragm valve 30. To the upper portion of the container 26 is attached a'plurality of conduits 31 corresponding to the number of cylinders in the engine. The conduits 31 terminate in the inlet port 24. p A vaporizing gas, such as nitrogen, air, carbon dioxide and the like, supplied from any convenient means such as a compressor or tank (not shown) through the conduit 2'81pa'sses through the manganese polycarbonyl compound 27 and carries the compound as a vapor through the conduit 31 to the inlet port 24 where at the appropriate time it passes through the aperture 18 into the combustion chamber 12 where it mixes with the gasoline and combustion air and improves the combustion which takes place under the influence of spark plug 13 at the end of the compression stroke of the piston 11. The manganese polycarbonyl compound shown at 27 may be in the form of a solid such as methyl manganese pentacarbonyl or may be a liquid which contains a non-ionic manganese polycarbonyl which may be blended with an antiknock fluid containing halogen scavenger material and an organolead antiknock agent such as tetraethyllead.

Fuels containing organolead antiknock agents ordinarily contain, in addition to the antiknock agent, corrective agents commonly termed scavengers. Thus, when organolead antiknock agents are present in the compositions of this invention, it is desirable to include therewith such scavengers. These scavengers consist of organo bromine and/or chlorine compounds such as ethylene dibromide, ethylene dichloride and like material. They function to inhibit the build-up of lead deposits on the interior surface of internal combustion engines.

Halogen containing hydrocarbons are useful as scavengers in conjunction with the manganese polycarbonyl antiknock agents and are conveniently blended therewith to form fluids which are added to gasoline to give the benefits of this invention. These fluids also may contain small amounts of such hydrocarbon solvents as kerosene as well as dyes, antioxidants and the like. The proportion of halogen in such compositions is adjusted such that an atom ratio of halogen to manganese of from about 0.221 up to 12:1 is achieved. However, the octane enhancement of the manganese polycarbonyl compounds is realized even in the absence of such scavengers.

Organolead antiknock agents are commonly provided as fluids for addition to hydrocarbon fuels. These fluids ordinarily contain the organolead compound and the halogen scavenger agents referred to above. In addition, these fluids also often contain solvents comprising mixtures of hydrocarbons as well as antioxidants and the like. Thus, another variant within the purview of this invention is the provision of an antiknock fluid comprising an organolead compound and a manganese polycarbonyl compound. These fluids are conveniently blended with hydrocarbon fuels to prepare the improved fuels of this invention.

Because of the property inherent in the manganese polycarbonyl compounds within the scope of this invention of being highly soluble in gasoline, such blending operations present little or no difficulties. It is generally necessary only to add the requisite quantity of an improved antiknock fluid of the present invention to gasoline; and, by stirring, shaking or otherwise mechanically agitating'these components, homogeneous improved fuel compositions are obtained. As a result of the high solubility of the'antiknock fluids of this invention in gasoline such fluids can be utilized in any commercially available gasoline including straight run, catalytically cracked, catalytically reformed and thermally cracked base stocks and likewise, blends thereof.

Among the manganese carbonyl compounds suitable for use in the present invention are those which have the empirical formula R Mn(CO) where R is an organic radical, x ranges from to '7 and y is an integer from 2 to 5. However, the non-ionic manganese polycarbonyl compounds preferred in the practice of this invention are those where R is a monovalent organic radical, x ranges from 0 to l inclusive, such that when x is 0, y is and when x is l, y is a small odd integer from 3 to 5 inclusive. R is most preferably a monovalent aliphatic hydrocarbon radical, such as an alkyl or aryl radical, or a monovalent acyl radical. Examples of these compounds include manganese carbonyl, methyl manganese pentacarbonyl, benzoyl manganese pentacarbonyl, phenyl manganese pentacarbonyl, acetyl manganese pentacarbonyl, and the like. These and other manganese polycarbonyl compounds exhibit extraordinary antiknock effect and other unexpected properties which render them of interest as commercial antiknock agents.

The relative size of the organic radical in the manganese carbonyl compounds, while not too important, is best limited to those having from 1 to about 20 carbon atoms, as it is found that these are best suited to the practice of this invention. Compounds having organic groups containing from 1 to 13 carbon atoms are preferred as these compounds are found to best combine the qualities of volatility and inductibility which are prerequisites to proper functioning as gasoline additives.

When x in the above generic formula is 0, the formula becomes Mn(CO) This compound exists, under some conditions, as the dimer having the formula [Mn(CO) 1 and is prepared, for example, by a process which man prises the reduction of a manganese halide with a reducing agent such as magnesium in the presence of a catalyst under pressure of carbon monoxide at elevated temperatures. Manganese carbonyl is recovered from the reaction mixture by acid hydrolysis followed by steam distillation.

Manganese carbonyl is a solid at ordinary temperatures, having a melting point when pure of about 155 C., and a density of about 1.2. The material possesses a vapor pressure of 1 millimeter of at C. Manganese carbonyl is stable in the ordinary sense of the term up to a temperature of about 200 C. It is soluble in gasoline, but is insoluble in water and aqueous solutions.

Compounds having the formula RMn(CO) where the R represents an organic radical from the group consisting of organic hydrocarbon radicals and organic oxygen containing radicals, are conveniently prepared from manganese carbonyl in an ether solution. Manganese carbonyl is first converted to an alkali metal salt such as the sodium salt by treating the solution with an alkali metal present by an alkali metal dispersion or amalgam. The alkali metal salt is then reacted with an alkylating agent such as a dialkyl sulphate to form an alkyl manganese pentacarbonyl. Alternatively, the alkali metal salt of manganese carbonyl is reacted with an acyl halide to form an acyl manganese pentacarbonyl compound. These acyl manganese pentacarbonyl compounds are converted to the corresponding lower alkyl or aryl manganese pentacarbonyl compounds by pyrolysis accompanied by the loss of CO at elevated temperatures. Thus, phenyl manganese pentacarbonyl is conveniently produced by the pyrolysis of benzoyl manganese pentacarbonyl.

The lowest molecular weight compound having the formula RMn(CO) is methyl manganese pentacarbonyl which is a crystalline solid melting at about C. and which is highly volatile and soluble in gasoline. Another compound of this class is benzoyl manganese pentacarbonyl, also a soluble crystalline solid, which melts at about 38 C. Propyl manganese pentacarbonyl and acetyl manganese pentacarbonyl are other representative members.

In order to illustrate the utility and some of the commercial advantages of employing the manganese carbonyl compounds used in the practice of this invention, a great number of tests have been conducted. The results of some of the most significant are presented below.

Another unexpected advantage which the manganese polycarbonyl compounds possess is their extremely low wear causing characteristics. To demonstrate the low wear rate caused by the use of manganese polycarbonyl compounds as compared to the Wear caused when iron containing compounds are employed for the same purpose, the following tests were conducted: Gasoline, con

taining manganese carbonyl on the one hand and iron carbonyl on the other, was employed in a single-cylinder engine having a displacement of 35' cubic inches operating at a speed of 1850 r.p.m. at a jacket temperature of 180 F. The intake air was filtered in order to prevent dust in the atmosphere from entering the combustion chamber. The amount of wear was determined according to the method disclosed in US. Patent 2,315,845. It is reported in Table I below as the rate of loss in weight of the upper piston ring during the test period, in terms of milligrams per hour. The piston ring in question was made of standard cast iron and contained radioactive isotopes. As the surface of this ring was subjected to .wear in the operation of the engine on a particular gasoline, the wear debris was carried into the lubricating oil where its concentration was measured by determining the radioactivity of the oil solution by means of a counting device. The radioactivity count was then compared with the count obtained from a standard solution of metal secured from the surface of a piston ring similar to the one used in the test. By appropriate mathematical calculations, the observed count of radioactivity of the oil was transformed to figures representing the loss in weight of the piston ring due to wear in the operating of the engine.

It is seen from Table I that at a concentration of the carbonyl compound equivalent to 0.21 gram of the metal per gallon of fuel, manganese carbonyl produces only 24 percent of the wear observed when iron carbonyl is used as the additive. It is further seen that when the concentration of the additive is increased to that equivalent to 0.62 gram of the metal per gallon of fuel, the amount of wear due to the use of manganese carbonyl is only 15.5 percent of that observed when iron carbonyl is the additive. Stating this in a different manner, iron carbonyl has been shown, as indicated in the above table, to produce from 416 percent to 645 percent as much wear as manganese carbonyl produced in the combustion chamber of the spark fired internal combustion engine when used as an antiknook additive in fuel. This further illustrates the desirability of employing a manganese polycarbonyl as an antiknock agent.

TABLE I Comparison of top piston ring wear in a single cylinder test engine Additive Sulfur cone. in content, Fuel/air Duration Wear Additive g. of Weight ratio of test, rate,

metal} Percent hours mgJhr.

gal.

PART I Fe(CO)s 0.21 0.080 23 0.646 Fe(CO)5- 0.21 0.065 19. 5 0.770 Fe(GO) 0.21 0.15 0.080 20 0.86 Fe(O 0. 21 0. 15 0. 080 23 1. 02

PART II M]1(C0)n 0.21 0. 065 18 0.241 Mn(0 0);; 0.21 0. 065 20. 25 0. 155

PART III Fe(C O)s 0.62 0. 080 22. 5 2. 36 Fe(OO)t 0. 62 0. 080 20 4. 52

PART IV Mn(O 0) 0.62 0.065 15 0.635

1 Average.

The unexpected nature of this drastic reduction in wear brought about by the use of a manganese polycarbonyl compound appears at once from a consideration of the relative hardness of the products of combustion of these compounds and iron antiknocks. The iron compounds produce oxides having relative hardness of aboutthe same magnitude as oxides produced by the manganese polycarbonyl compounds. Therefore, the great difference in wear cannot be accounted for in terms of the hardness of the products of combustion, but rather it would be expected that they cause wear of about the same magnitude.

A most important feature of the present invention is the outstanding antiknock activity exhibited by the nonionic manganese polycarbonyl compounds. For example, the octane rating of typical test gasolines to which had been added in varying proportions a manganese polycarbonyl, as well as other previously known metal carbonyl compounds and tetraethyllead was determined by the Research Method. The Research Method of determining the octane number of a fuel is generally accepted as a method of test which gives a good indication of fuel behavior in full-scale, automotive engines under normal driving conditions and the method most used by commercial installations in determining the value of a gasoline or additive. The Research Method of testing antiknocks is conducted in a single-cylinder engine especially designed for this purpose and referred to as the CFR engine. This engine has a variable compression ratio and during the test the temperature of the jacket water is maintained at 212 F. and the inlet air temperature is controlled at F. The engine is operated at a speed of 600 rpm. with a spark advance of 13 before top dead center. The test method employed is more fully described in test procedure D-908 55 contained in the 1956 edition of ASTM Manual of Engine Test Methods for Rating Fuels.

The results of these tests are summarized in Table II. In brief, they demonstrate that the manganese polycarbonyl compounds are unexpectedly superior to previously used metal carbonyl antiknock agents such. as iron carbonyl. The tests also show that the non-ionic manganese polycarbonyl compounds are vastly more effective than the present commercial anti'knook agent, tetraethyllead as is indicated by the fact that 1.77 grams of manganese as manganese carbonyl is as eifectiye as 3.3 grams of lead as tetraethyllead.

The tests shown in Table H were conducted .in two different test gasolines, one having a research octane number rating of 60 without additives (designated as A), the other having a rating of 70 octane numbers (designated as B).

In addition to the remarkable antiknock activity of the manganese polycarbonyl compounds, the tests shown in Table II point out the unexpectedness of this property. Tungsten and chromium are both closely neighboring elements to manganese in the periodic classification but as the tests show, the carbonyls of these elements both exhibit strong pro-knock activity. Similar tests were also conducted using a rhenium containing carbonyl compound as an additive. The results of these tests showed the compound to have absolutely no antiknock elfect on the gasoline.

The antiknock properties of manganese polycarbonyl compounds are even more unexpected when it is considered that some other compounds of manganese are inefiective. For example, manganese naphthenate exhibits a slight pro-knock quality.

In a series of tests conducted with a multi-cylinder engine having a 11.3:1 compression ratio, small amounts of manganese polycarbonyl compounds were added to the gasoline which contained 3 milliliters of tetraethyllead per gallon and the octane number of the resulting gasoline was determined by the borderline rating method to show the synergism existing between a lead anti-knock agent and a small amount of manganese. When 0.062 gram of manganese per gallon as manganese carbonyl was added to the gasoline, an increase in octane quality was obtained which is the equivalent of that obtained with 3.60 milliliters of tetraethyllead. Thus, the 0.062 gram of manganese gave about 950 percent of the effect obtainable with the same amount of lead.

In order to demonstrate the synergistic effect produced by utilizing a larger amount of a manganese polycarbonyl compound in combination with an organolead antiknock agent, a number of similar engine tests were conducted utilizing the same fuel base stock to which had been added various concentrations of a typical non-ionic manganese polycarbonyl material, manganese carbonyl. By so doing, it was found that a concentration of this material equivalent to 1.0 gram of manganese per gallon resulted in an antiknock quality equivalent to that produced by 1.9 grams of lead per gallon as tetraethylleacl. Similarly, when 1.5 grams of manganese per gallon was present as manganese carbonyl, the octane quality was found equivalent to that produced by the addition of 3.8 grams of lead per gallon as tetraethyllead. The tests were conducted according to the Research Method referred to above. Thus, one gram of manganese as manganese carbonyl was the equivalent of 2.8 grams of lead when used in conjunction with one gram of lead instead of the 1.9 grams of additional benefit which was expected from the manganese. Therefore, the mixture of tetraethyllead and manganese carbonyl exhibited a synergism equal to an additional 0.9 gram of lead for each gram of manganese. Thus, the unexpected improvement in the octane quality of a gasoline was of the order of 152 percent. Similar results, as indicated by Table III, were obtained when 1.5 grams of manganese as manganese carbonyl were used in conjunction with one gram of lead as tetraethyllead per gallon of the same gasoline. In this case, the expected effect would be equivalent to a total of 3.85 grams of lead as tetraethyllead. However, the total eliect produced by 1.5 grams. of manganese as manganese carbonyl and one gram of lead as tetraethyllead was equivalent to that produced by 6.4 grams of lead alone. Thus, the mixture exhibited a synergism of 190 percent over and above the effect expected from the manganese alone.

TABLE III Metal Content Antiknoek Eileetiveness Percent Improvement Mn, Pb, Expected Obtained gJgal. gJgal.

pyllead, and the like.

12 are summarized in Table IV from which it can be seen thatthe addition of a relatively small quantity of an organo manganese pentacarbonyl, such as methyl manganese pentacarbonyl, greatly improves the octane number of the gasoline,

The following examples are illustrative of the novel gasolines, lubricating oils and antiknock fluids which are within the scope of this invention.

EXAMPLE I A typical method of providing fuels containing a dissolved manganese polycarbonyl compound is as follows: To a gasoline having a final boiling point of 406 in a vessel provided with an agitator is added 6.29 parts of manganese pentacarbonyl per gallon of the gasoline. After agitating the mixture for approximately fifteen minutes, the manganese carbonyl was completely dissolved and uniformly distributed throughout the fuel. This is demonstrated by analysis of a portion of the fuel for manganese, which shows the fuel to contain 1.77 grams of manganese per gallon of fuel mixture.

EXAMPLES II-VIII Other improved gasoline compositions of this invention prepared as in Example I are illustrated in Table V. The initial boiling points (IE?) and final boiling points (FBP) of the gasolines used are indicated as well as the particular manganese polycarbonyl compounds and their concentrations in terms of grams of manganese per gallon of gasoline. Other such improved gasoline compositions will be apparent to one skilled in the art.

TABLE V Gasoline containing manganese polycarbonyl compounds Gasoline Grams Ex. Manganese Polyearbonyl Mn Compound per IBP FBP Gal.

406 Manganese pentacarhonyl 0. 01 94 390 s -do 10.0 94 390 Aeetyl manganese pentaearbonyl- 6. 0 84 392 Ethyl manganese pentacarbonyl. 0. 1 89 385 Methyl manganese pentacarbonyl 2. 0 98 378 Manganese pentaearbonyl 4. 0 94 390 Propionyl manganese pentaearbonyl 1. 3

EXAMPLES 1XXIX Table VI illustrates typical gasolines of this invention which contain a non-ionic manganese polycarbonyl compound in conjunction with an organolead compound.

The organolead antiknocks which are ingredients of certain of the compositions of this invention are preferably hydrocarbon lead compounds such as tetraphenyllead, tetratolyllead and particularly tetraalkyllead compounds such as tetramethyllead, tetraethyllead, tetrapro- Tetraethyllead is preferred. In general, the amount of organolead antiknock agent is selected so that its content of the gasoline is equivalent to about 0.1 to-about 8 grams of lead per gallon of gasoline. v

TABLE VI Gasoline Man- Grams Scav- Example Manganese Polycarbonyl Additive ganese, Lead Antiknoek of Pb Scavenger enger Per- Gravg./gal. Agent per gal. nc., cent FBP ity, g./gal

S API IX 0 02 426 61. 4 Manganese pentacarbonyl 0. 25 Tetraethyl-lead. 3. 17 {figgfiggg g ggggigg: g Y Ethylene dichloride. 1.48 X o. 02 426 61.4 d0 0.1 do s. 17 {Ethylenedipmmidk 5 426 61.4 Methyl manganese pentacarbonyl 6.0 do 3.17 {ggfifiggg 390 59.0 p-OcItyl benzoyl manganese pentacarbo- 2.4 Tetramethyl-lead. 2.0 Dibromobutane 2 1 ny 366 54. 6 Nonoyl manganese pentacarbonyl 4.0 Tetraphenyl-lead. 0.05 385 64.4 Acetyl manganese pentacarbonyl 0. 03 Tetraethyl-1ead 8.00 {gggggg g giggg fi 420 61.4 Benzoyl manganese pentaearhonyl 8.0 Tetrabutyl-lead-.. 0.1 416 63. 2 Phenyl manganese pentacarbonyl 0.,9 Tetraethyl-lead-.. XVII 0.02 426 61.4 Methyl manganese pentaearbonyL; 0.05 do XVIII 420 60. 8 Manganese pentacarbonyl .10

Other compositions of this invention comprising an improved gasoline containing a non-ionic manganese polycarbonyl compound are prepared in a manner similar to that described above and illustrated in Examples I through XIX. Further, illustrative examples of the nonionic manganese polycarbonyl compounds utilized alone or in admixture in such improved gasolines include propionyl manganese pentacarbonyl, phenyl manganese pentacarbonyl, benzoyl manganese pentacarbonyl, trimethyl manganese tetracarbonyl, benzyl manganese pentacarbonyl, m-ethylbenz'yl manganese pentacarbonyl, and the like.

'Where halohydrocarbon compounds are employed as scavenging agents, the amounts of halogen used are given in terms of theories of halogen. A theory of halogen is defined as the amount of halogen which is necessary to react completely with the metal present in the antiknock mixture to convert it to the metal dihalide, as, for example, lead dihalide and manganese dihalide. In other words, a theory of halogen represents two atoms of halogen for every atom of lead and/or manganese presenti In like manner, a theory of phosphorus is the amount of phosphorus required to convert the leadpres ent to lead onthophosphate, Pb '(PO that is, a theory of phosphorus based on lead represents an atom ratio of two atoms of phosphorus to three atoms of lead. When based on manganese, a theory of phosphorus likewise represents two atoms of-phosphorus for every three atoms of manganese, that is sufficient phosphorus to convert manganese to manganese orthophosphate, 1

Mnsi oz- The scavenger compounds can be halohydrocarbons both aliphatic and aromatic in nature, or a combination of the two, with halogens being attached to carbons either in the aliphatic or the aromatic portions of the molecule. The scavenger compounds may also be carbon, hydorgen and oxygen-containing compounds, such as haloalkyl ether, halohydrins, halo esters, halonitro compounds, and the like. Still other examples of scavengers that may be used in conjunction with my manganese compounds either with or without hydrocarbolead compounds are illustrated in US. Patents 2,398,281 and 2,479,900903, and the like. Mixtures of different scavengers may also be used. These fluids can contain other components as stated herein above. In like manner, manganese-containing fluids are prepared containing from 0.01 to 1.5 theories of phosphorus in the form of phosphorus compounds. To make up the finished fuels, the concentrated fluids are added to the gasoline in the desired amounts and the homogeneous fluid obtained by mixing, agitation, etc.

EXAMPLE XX To 11 parts of methyl manganese pentacarbonyl is added 5 parts of ethylene dichloride and the mixture agitated until. a homogeneous fluid results. The manganese to chlorine atom ratio in this fluid is 1:12 and represents 6 theories of halogen based on the manganese.

In like manner, a fluid is prepared comprising benzyl manganese pentacarbonyl and ethylene dibromide in which the manganese to bromine ratio is 1:6, representing 3 theories of bromine based on the manganese. Likewise, a fluid containing manganese pentacarbonyl, ethylene bromohydrin, and 2,3-dichloro-1,4-dimethylbenzene is prepared in such proportions that for every atoms of manganese, there are one atom of bromine and two atoms of chlorine, representing a total of 0.02 theory of halogen.

The above fluids are added to hydrocarbon fuels in amounts so as to provide improved fuels containing 0.015 gram, 0.25 gram, 1.00 gram, 6 grams and 10 grams of manganese per gallon.

EXAMPLE XXI To 8.0 parts of lead in the form of tetraethyllead inan antiknock fluid containing 0.5 theory of bromine as ethylene dibromide and 1.0 theory of chlorine as ethylene dichloride, wherein the theories of halogen are based upon the amount of lead present, is added 0.015 part of manganese in the form of an equimolar mixture of manganese pentacarbonyl and acetyl manganese pentacarbonyl.

This fluid is then added to a commercial hydrocarbon fuel having an initial boiling point of 82 F. and a final boiling point of 420 F. in an amount so as to provide 8.0 grams of lead and 0.015 gram of manganese per gallon.

EXAMPLE XXII A concentrated fluid is prepared as in Example XX containing kerosene, a blue dye, and 10 parts by weight of manganese as an equimolar mixture of methyl manganese pentacarbonyl and benzoyl manganese pentacarbonyl for every 0.02 part of lead in the form of diethyldimethyllead. This fluid is then blended with a commercial hydrocarbon fuel having an initial boiling point of F. and a final boiling point of 394 F. in an amount suflicient to provide 10 grams of manganese and 0.02 gram of lead per gallon.

EXAMPLE XXIII Tetraethyllead and manganese 'pentacarbonyl are admixed so that the ratio is 2.0 grams of lead as tetraethyllead present for every 1.0 gram of manganese present as manganese carbonyl. This composition is found to possess superior antiknock and deposit modifying properties when added to gasoline.

EXAMPLE XXIV To the composition of Example XXIII is added ethylene dibromide in amount such that there is one theory of scavenger present based upon the total amount of metal.

The amount of the improved antiknock fluids of this invention containing organolead compounds and manganese polycarbonyl compounds employed in gasoline is dependent primarily upon the use for which the gasoline is intended. In gasolines for use in automotive engines, such as passenger cars, trucks, buses, and the like, amounts of any of the compositions of this invention equivalent to from between about 0.1 and about 4.3 grams of lead per gallon are satisfactory. It will be appreciated, however, that in most cases the lead content of such improved fuels is preferably from between about 1.06 and about 3.17 grams of lead per gallon which, when the organolead constituent of such fuels is tetraethyllead, is equivalent to from between about 1 and about 3 milliliters of tetraethyllead per gallon. When the improved gasolines of this invention are designed primarily for use in aviation engines, somewhat greater concentrations can be tolerated and are frequently preferred. In such instances, it is advantageous to employ an amount of improved antiknock fluid of this invention equivalent to from between about 3.17 and about 6.34 grams of lead per gallon. That is to say, when utilizing a tetraethyllead-containing antiknock fluid of the present invention in an aviation fuel, amounts of such a fluid equivalent to from between about 3 and about 6 milliliters of tetraethyllead per gallon are satisfactory. Concentrations above these limits can be employed in both motor and aviation fuels, practical considerations being the prime criterion for establishingrthe upper concentration limit.

Use-of antiknock fluids containing non-ionic manganese polycarbonyls in addition to resulting in great convenience in storage, handling, transportation, blending with fuels, and so forth, also are unexpectedly potent concentrates which serve the multi-purpose functions of being useful asantiknocks, deposit modifiers, valve corrosion'inhibitors, wear reducers, and the like. The fluids are also found to. possess a surprising degree of inherent stability. I

The gasolines to which the antiknock compositions of this invention are added are mixtures which may have a wide variation of compositions. These fuels can contain all types of hydrocarbons, including paraffins, both straight and branched chain; olefins; cycloaliphatics containing paraflin or olefin side chains; and aromatic containing aliphatic side chains. The gasoline type depends on the base stock from which it is obtained and on the method of refining. For example, it can be a straight run or processed hydrocarbon, including thermally cracked, catalytically cracked, reformed fractions, etc. When used for spark-fired engines, the boiling range of the components of gasoline can vary from zero to about 430 F., although the boiling range of the fuel blend is often found to be between an initial boiling point of from about 80 F. to 100 F. and a final boiling point of about 430 F. While the above is true for ordinary gasoline, the boiling range is a little more restricted in the case of aviation gasoline. Specifications for the latter often call for a boiling range of from about 82 F. to about 338 F., with certain fractions of the fuel boiling away at particular intermediate temperatures. All commercial gasolines including all those embraced within the present invention, always contain a great number of individual hydrocarbon compounds as components and always have a final boiling point of at least 300 F.

The gasolines in which the antiknock agents of this invention can be employed often contain minor quantities of various impurities. One such impurity is sulfur which can be present either in a combined form as an organic or inorganic compound or as the elemental sulfur. The amounts of such sulfur can vary in various fuels from about 0.003 percent to about 0.30 percent by weight. Fuels containing quantities of sulfur, both lesser and greater than the range of amounts referred to above, are also known.

For best results for increasing spark plug life, the improved gasolines of this invention should contain at least 0.015 weight percent of sulfur and preferably between 0.015 and 0.065 weight percent of this element. Spark plug life with such gasolines is spectacularly increased. These gasolines may also contain organolead antiknock agents in the amounts specified above.

It will be apparent that the present invention is susceptible of additional variations. Some of these variants include the utilization in the antiknock fluid embodiments of solubilizing agents, such as kerosene, petroleum cuts or fractions, and in general various aromatic solvents including those containing diphenyl and the like. In addi tion to this, various organolead stabilizers can be used in such embodiments. Among such materials are included styrene, naphthalene, lecithin, aminodiphenyl amines, phenyl-a-naphthyl amine and analogous materials. Likewise, in both the antiknock fluid and antiknock fuel embodiments of this invention it is frequently advantageous to employ minor proportions of antioxidants, particularly those of the phenylene diamine type as well as the various alkyl phenols. A still further variant within the contemplation of this invention relates to the utilization of various organic dyestuffs in the antiknock fluid embodiments of this invention, which materials serve primarily as a means of product identification, although frequently the coloration produced by such dyestuffs imparts to the composition a degree of stabilization against deterioration resulting from exposure to light. Furthermore, under certain circumstances benefits are to be obtained by utilizing as the scavengers in the diverse compositions of the present invention, organic halides possessing volatilities comparable to that of the organolead antiknock agent utilized. Such scavengers are described in several of the patents cited hereinbefore.

The improved gasolines and fluids of the present invention can be utilized in conjunction with other well known motor fuel adjuvants. Of such materials, the various catalytically active substances, such as phosphorus compounds comprising various phosphates, phosphites, phosphonates and the like can thus be used in various embodiments of this invention. Other. variants within the contemplation of this invention will be apparent to those skilled in the art.

The manganese polycarbonyl containing additives of this invention may be mixed with antioxidants, such as alkylated phenols and amines, metal deactivators, phosphorus compounds; antiknock agents, such as amines as well as the alkyllead compounds mentioned above; antirust and anti-icing agents, and wear inhibitors.

EXAMPLE XXV To 500 parts of a commercially available neutral crankcase lubricating oil is added a quantity of manganese pentacarbonyl suflicient to produce a composition containing about 2.5 weight percent manganese. The mixture is agitated until the manganese pentacarbonyl is completely dispersed in the oil.

EXAMPLE XXVI To 10,000 parts of a wholly-distilled mixed base, solvent-refined lubricating oil having a gravity of 289 API, a viscosity grade of SAE 10W-20 and a viscosity index of 135.7 is added parts of manganese as 2,4,6- triethylbenzyl manganese pentacarbonyl and the mixture is stirred until a homogeneous solution is obtained.

EXAMPLE XXVII To 1000 parts of a mixed-base, solvent-refined lubricating oil containing bright stock and which has an SAE mixture is stirred until the benzoyl manganese pentacarbonyl is dissolved.

EXAMPLE XXIX H To 216 parts of a wholly distilled lubricating oil having an API gravity of 29.1, an SAE number of lW-30 and a viscosity index of 13819 is "added 3 percent of manganese as manganese pentacarbonyl. The mixture is agitated until a homogeneous solution is obtained.

The lubricating oils used in the practice of this invention include those fractions or blends of fractions from mineral oils which are used for lubricating purposes in the crankcase of an internal combustion engine. Lubricating oil stock is usually considered to include all the distillate obtainable from crude oils after the lower boiling fractions and gas oils have been expelled, as well as some of the residues that are left in the still when non-asphaltic crudes are distilled.

Generally lubricating oils are made from distilled fracions of a crude, but often these distilled fractions are combined with refined residuum, such as bright stocks, to yield oils having excellent lubricating qualities.

in addition to the non-ionic manganese pentacarbonyl compound, the lubricating oils of this invention may contain ether additives. These other additives may include, for example, viscosity index improvers, detergents, corrosion inhibitors, metal deactivators, rust inhibitors, color stabilizers, pour depressants, emulsifiers, dyes, etc.

The non-ionic manganese polycarbonyl compounds used in the practice of this invention are prepared by various methods. Examples of these are indicated below.

EXAMPLE XXX pentacarbonyl, styryl manganese pentacarbonyl, and the like.

EXAMPLE XXXI Benzoyl manganese pentacarbonyl is prepared in a manner similar to that described in Example XXX by reacting benzoyl chloride with sodium manganese pentacarbonyl. The benzoyl manganese pentacarbonyl is gently heated to above 90 C. at which temperature a strong evolution of gas is readily identified as carbon monoxide. When the gas evolution ceases, the remaining product is found on analysis phenyl manganese pentacarbonyl.

EXAMPLE XXXII Manganese bromide, methyl lithium, and carbon monoxide are contacted in the presence of dioxane as a solvent at a CO pressure of about 5000 p.s.i.g. at 300 C. for twelve hours. A good yield of trimethyl manganese tetracarbonyl is subsequently separated from the reaction mixture.

When the non-ionic manganese polycarbonyl compounds used in the practice of this invention contain an organic radical, such radical has, in general, from 1 to "about 20' carbon atoms. Thus, compounds -s'uital5jle for use in the process of this invention include B ll .8 v manganese pentacarbonyl, heptaethyl manga'n" bonyl, dibutyl manganes tetraca'rbonyl, methyl 'manganese pentacarbonyl, trioctyl manganese tetracarbonyl, "and the like. Theseeom'poun'ds have a molecular Weight from about '194 to about 50p1(manganesecarbonyl itself exists as the dimer [Mn(CO)5] andhas a'r'nolecular weight of about 390).

When the organic "group 'is a hydrocarbon radical, it preferably has from l"'to'about 13 carbon atonrs'an'd the manganese polycarbonyl compound which .cont'ainsit has a molecular weight up toabout 450. "Examplesjof such non-ionic manganese polycarbonyl compounds include ethyl manganese pentacarbonyl, allyl manganese pentacarbonyl, triheptyl manganese tetracarbonyl,ipentapi'bpyl 'rnanganese tricarb'onyl, "phenyl manganese'penta arbpnyl, p-hexyl benzyl manganese pentacarbonyl, andthe'like.

Likewise, when the organic group is an acyl radical or an acylated hydrocarbon radical, it preferably contains up to about 13 carbon atoms and the non-ionic manganese polycarbonyl compound has a molecular weight up to about 465. Examples of these compounds include benzoyl manganese pentacarbonyl, tripropionyl manganese tetracarbonyl, stearoyl manganese pentacarbonyl, heptaacetyl manganese dicarbonyl, and the like.

The present invention resides in the discovery that the non-ionic manganese polycarbonyl compounds are unexpectedly beneficial with regard to antiknock effect and deposit-modifying properties when used in conjunction with the operation of a spark ignition internal combustion engine. The invention gives rise to a number of embodiments including a novel process for operating such an engine by means of introducing a non-ionic manganese polycarbonyl compound into the combustion chambers, and a number of novel compositions which are of particular benefit in such a process. These novel compositions include a liquid hydrocarbon mixture for use in such an engine which mixture contains a nonionic manganese polycarbonyl compound. This liquid hydrocarbon mixture, as has been pointed out, may be .a gasoline or a lubricating oil. When the hydrocarbon is a gasoline it may contain an organo-lead antiknock agent and appropriate halohydrocarbon scavengers in addition to the manganese polycarbonyl compound. Suitable organolead compounds include the alkyl lead compound, tetraethyllead, which may be present in amount such that up to 6.34 grams or more of lead are present per gallon of fuel. The atom ratio of manganese to lead may be from about 0.05 to 1 to 64 to 1, or, expressed differently, from about 1 to 20 to about 64 to l. Applicable halohydrocarbon scavengers include ethylene dichloride and ethylene dibromide.

Further novel compositions of particular benefit in conducting the process of this invention comprise antiknock fluids containing a non-ionic manganese polycarbonyl. Fluids containing halohydrocarbon scavengers along with the non-ionic manganese polycarbonyl compound are also within the scope of this invention, as are fluids containing organolead antiknock agents in addition to the non-ionic manganese polycarbonyl compounds. Illustrative of such fluids are those containing manganese carbonyl and tetraethyllead such that the atom ratio of manganese to lead is from about 0.05 to about '64 to 1. These fluids are conveniently added to gasolines to give composition containing up to 6.34 or more grams of lead per gallon.

A variant in the practice of the present invention comprises the use of a non-ionic manganese polycarbonyl compound wherein the organic group is substituted with a non-ionic, non-reactive group.

Having fully described the nature of the present invention, the need therefor, and the best modes derived for carrying it out, it is intended that this invention be 19 limited only within the spirit and scope of the appended claims.

Iclaimz .1. A liquid hydrocarbon crankcase lubricating oil containin'g from about 0.05 to about 10.0 weight percent manganese as manganese pentacarbonyl.

I about 64:1.

"5. Gasoline containing a small antiknock quantity of manganese pentacarbonyl. V

References Cited in the file of this patent UNITED STATES PATENTS 1,954,865 Danner Apr. 17, 1934 2,398,282 Bartholomew Apr. 9, 1946 2,434,578 Miller: Ian. 13, 1948 2,763,617 Scott et a1. Sept. 18, 1956 FOREIGN PATENTS 1,092,700 France Nov. 10, 1954 OTHER REFERENCES Jour. of the Institute of Petroleum Technologists, vol. 13, 1927, pp. 244-255.

Jour. Amer. Chem. Soc., vol. 71, 1949, page 1899.

M a. with

Claims

1. A LIQUID HYDROCARBON CRANKCASE LUBRICATING OIL CONTAINING FROM ABOAUT 0.05 TO ABOUT 10.0 WEIGHT PERCENT MANGANESE AS MANAGANESE PENTACARBOXYL.