US2843463A - Non-stalling gasoline fuel compositions - Google Patents

Description

United States Patent NON-STALLING GASOLINE FUEL COMPOSITIONS Gardner 'E.'Gaston, Tarentum, and John P. 'Pellegrini, Jr.,

Blawnox, Pa., 'assignors to Gulf Research 8; Development Company, Pittsburgh, Pa, n corporation of Delaware No Drawing. Application September 12, 1955 Serial No. 533,920

6 Claims. (CI. 44-58) This invention relates to non-stalling gasoline fuel compositions that are adapted to improve the operation of internal combustion engines under cool, humid atmospheric conditions. More particularly, the invention relates to gasoline fuel compositions that contain a small amount, sufficient to reduce the tendencies of the comhaving a relatively low 50 percent ASTM distillation p'oint, engine stalling is apt to be encountered at idling speeds during the warm-up period, especially where engine idling occurs following a period of light load opera 'tion. Engine stalling under such conditions has been attributed to the partial or complete blocking of the narrow air passage that exists between the carburetor throat and the carburetor throttle valve during engine idling, by ice particles and/ or solid hydrocarbon hydrates that de posit upon and adhere to the metal surfaces of the carburetor parts. Such icing of carburetor parts occurs as a result of the condensation of moisture from the air drawn into the carburetor and as a result of the solidification of such condensed moisture. The aforesaid condensation and solidification of moisture are caused by the refrigeratin'g "effect of rapidly evaporating gasoline. Accordingly, excessive engine stalling due to carburetor icing occurs as a practical matter only in the instance of gasolines containing a large proportion of relatively highly volatile components.

Excessive engine stalling is, of course, a source of annoyance owing to the resulting increased fuel consumption, battery wear and inconvenience of frequent restarting. It is therefore important that in inherent engine stalling characteristics of gasoline fuels be reduced substantially, where 50 percent ASTM distillation point of such gasoline fuels is sufficiently low to cause a problem in this respect.

We have found that the stalling characteristics of gasoline fuel compositions having a 50 percent ASTM distillation point below about 220 F. and that normally tend to promote engine stalling due to carburetor icing are markedly improved by the incorporation therein of a small amount of the oil-soluble still bottoms from the distillation of the products obtained by subjecting a mono-olefin containing 6 to 8 carbon atoms to the 0x0 synthesis process, to recover primary alcohols containing one more carbon atom than the mono-olefin. In one embodiment of the invention the gasoline composition also contains about 0.25 to about 0.75 percent by volume of the composition of a light lubricating oil having a viscosity at 100 F. of about 50 to about 500 Saybolt Universal seconds.

The 0x0 bottoms anti-stalling agents disclosed herein contain substantial proportions of polar, surface-active ice materials. While the invention is not limited to any theory of operation, it might appear that these polar components tend to orient themeselves upon the metal surfaces of the throttle valve and other critical carburetor parts contacted by the gasoline composition, thus forming a moisture-displacing, residual coating on said carburetor parts, which coating tends to prevent the adherence to said metal surfaces of accumulations of ice of magnitudes sutficient to block the narrow air passages that exist in carburetor throats at engine idling conditions. It isalso considered that the polar components of the 0x0 bottoms may orient themselves about small individual water 'or ice particles, thus tending to prevent the formation of macrocrystals of ice of a size sufficient to block carburetor -air passages at engine idling conditions. Although the effectiveness of the herein disclosed addition agents is believed to be attributable at least in part to the polarcharacteristics thereof, this :general explanation is somewhat negatived by the fact that many oil-soluble polar agents have little or no effect upon engine stalling due to carburetor icing.

When the herein disclosed Oxo bottoms anti-stalling agents are utilized in gasoline compositions that contain a small amount of a light lubricating oil, it might appear that the 0x0 bottoms, by virtue of its afiinity for the lubricating oil, tends to attract the oil to the same critical carburetor surfaces referred to above, while simultaneously increasing the spreading and .metal wetting characteristics of the oil, thus promoting the formation "of an adherent oil film on the metal surfaces of the carburetor parts. The oil film therefore would appear to function similarly as the Oxo bottoms, but the superior metal wetting properties imparted to the oil by the additives are believed to enable the oil to displace moisture from metal carburetor surfaces that it would not thoroughly displace alone.

The oil-soluble Oxo bottoms which are suitable for the purposes of this invention are believed to comprise complex mixtures containing predominantly materials from the group of acetals, hemi-acetals, esters, ethers, aldol condensation products, alcohols and acids. Oil-soluble Oxo bottoms included by this invention are obtainable as still bottoms from the distillation of the products obtained by subjecting a mono-olefin contining 6 to 8 car bon atoms to the Oxo synthesis process, to recover primary alcohols containing one more carbon atom than the mono-olefin. Thus, for example, the 0x0 bottoms obtained as still bottoms from the distillation of C OX0 alcohols from the product obtained by subjecting mixed heptene isomers to the 0x0 synthesis process might contain C16 17 esters, c3 acids, (:16 a lCOhQlS, C16 aldol Con densation products, C acetals, C hemiacetals, and C ethers.

The Oxo synthesis process .is well known in this country, being practiced commercially by several manufacturers. Briefly, this process comprises subjecting a monoolefin, such .as hexene, heptene, or octene, usually in the form of a mixture of isomers such as can be obtained by fractionation of the products obtained by non-selective polymerization of the C C or mixed C andC monoolefins present in petroleum refinery gases, 'to hydroformylation in order to form a mixture of oxygenated products, principally aldehydes having one more carbon atom per molecule than the original mono-olefin. The aldehydic 'hydroformylation products are then subjected to catalytic hydrogenation to form a mixture containing predominantly isomeric branched chain primary monohydric alcohols containing one more carbon atom per molecule than the original mono-olefin. The hydroformylati-on reaction is normally effected by reacting the mono-olefin with equimolar proportions of hydrogen 4 purposes of this invention.

and carbon monoxide at a pressure of about 1500 to about 4500 p. s. i. g., and at a temperature of about 260 to about 460 F., in the presence of a cobalt catalyst, usually in the form of a salt of a suitable organic acid such as a naphthenic acid or a fatty acid, the latter preferably containing at least 6 carbon atoms per molecule. The catalytic hydrogenation of the aldehydic'hydroformylation product is normally effected with gaseous hydrogen in the presence of a suitable hydrogenation catalyst, e. g., nickel, nickel oxide, molybdenum sulfide and the like, preferably deposited upon an inert carrier, at a pressure of about 50 to about 5000 p. s. i. g. and at a temperature of about 290 to about 400 F.

Distillation of the products of the x0 synthesis reaction will yield a major proportion of a mixture of isomeric primary monohydric alcohols containing one more carbon atom per molecule than the mono-olefin charged to the hydroformylation reaction, and an Oxo bottoms distillation residue comprising a minor fraction of the over-all Oxo synthesis product, for example, percent. In the case of the still bottoms products, the use of which is included by this invention, the bottoms products will comprise predominantly materials boiling above the boiling point of the highest boiling isomer of the primary alcohol mixture produced in the 0x0 synthesis reaction. Thus, in the instance of the Oxo bottoms obtained from the distillation of C Oxo alcohols, the bottoms product will comprise predominantly material boiling above about 331 F. at 760 mm. Hg. In the instance of the Oxo bottoms product obtained from the distillation of C alcohols, the bottoms product will comprise predominantly material boiling above about 378 F. at 760 mm. Hg. In the instance of the 0x0 bottoms product obtained from the distillation of C Oxo alcohols, the bottoms product will comprise predominantly material boiling above about 401 F. at 760 mm. Hg. Oxo bottoms obtained from the sources indicated above, the predominant portion of which boils above the respective specified temperatures, are suitable for the It should be noted that the specific temperatures set forth above are temperatures above which substantially all, but not necessarily one hundred per cent, of the bottoms product will boil, since it will be appreciated that the presence of small amounts of 0x0 alcohols or water in the still bottoms can lower the initial boiling point somewhat below the values specified above. A specific example of an Oxo bottoms product, the use of which is included by the invention and with which excellent results have been obtained, is the oil-soluble still bottoms obtained by distillation overhead of C Ox-o alcohols from the product obtained by hydroformylation of mixed heptene isomers, obtained in turn by fractionation of the product of non-selective polymerization of mixed C C olefin fraction, at 3500 p. s. i. g. and 350 F., in the presence of a cobalt octanoate catalyst, and by hydrogenation of the resulting aldehydic product with gaseous hydrogen at 1000 p. s. i. g. and 380 F. in the presence of a reduced nickel oxide catalyst. A typical sample of the still bottoms as indicated above was found to be essentially completely insoluble in water and to have the following additional characteristics Inspections:

Acetyl No 166.8 Hydroxylamine No 159.4 Neutralization No 9.9 Saponification No 39 Specific gravity: 68/68 F 0.8569

Distillation, F. (corrected to 760 mm. Hg):

Over point 327 End point (extrapolated) 730 2% evap. at F. (corrected to 760 mm.

Since the boiling point of the highest boiling isomer present in C Oxo alcohols is approximately 378 F. at 760 mm. Hg, essentially all 99 percent) of the bottoms product described above boiled above this temperature. The low initialv boiling point for the abovedescribed still bottoms product is attributable to the presence of a small amount of water.

The Oxo bottoms anti-stalling agents described herein are useful when incorporated in gasoline compositions of the type disclosed in an amount sufficient to reduce the engine stalling characteristics thereof. For example, a good improvement in the stalling characteristics of gasolines of the type disclosed will normally be obtained by the addition thereto of the herein disclosed Oxo bottoms products in amounts of at least 0.05 percent by volume of the composition. Preferably the 0x0 bottoms antistalling agents disclosed herein will be employed in proportions of at least about 0.2 percent by volume of the composition. Excellent results have been obtained by the addition of 0x0 bottoms of the kind disclosed herein to gasoline compositions in proportions between 0.2 percent and 1.0 percent by volume of the composition, and this constitutes the preferred concentration range for the purposes of this invention. Although in some instances it may be desired to employ the 0x0 bottoms anti-stalling agents in amounts of up to about 1.75 percent by volume or more, such higher concentrations are less preferred since the degree of improvement in the stalling characteristics of the gasoline, per unit increment of Oxo bottoms, is relatively low. In no instance should the 0x0 bottoms additive disclosed herein be added to the gasoline in amounts such as to produce an undue adverse effect on the volatility, combustibility, anti-knock or gum-forming characteristics of the gasoline.

It will be appreciated that the optimum concentration of the disclosed Oxo bottoms anti-stalling agents can vary within the disclosed range according to the particular gasoline employed, since the problem of engine stalling due to carburetor icing is a function of the 50 percent ASTM distillation point of the gasoline. Thus, greater concentrations of the additive are normally desirable with decreasing 50 percent ASTM distillation point. The optimum concentration of the OX0 bottoms anti-stalling agents can also vary somewhat according to the particular make and model of engine in which the gasoline is used and also according to the severity of the atmospheric conditions encountered. With regard to the last mentioned factor, the problem of engine stalling due to carburetor icing resulting from the refrigeration by evaporating gasoline of moisture condensed from the atmosphere has been observed to be significant at temperatures between about 30 and 50 F., e. g., 35, 40, 45, 50 F., and when the relative humidity is in excess of about 65 percent, e. g., 75, 85, 99 percent. The optimum concentration of the OX0 bottoms anti-stalling agents will be one that is suflicient to effect a substantial reduction in the stalling tendencies of the fuel at the atmospheric conditions of tempertaure and humidity which are likely to be encountered in service.

Practically speaking, the problem of engine stalling due to carburetor icing caused by rapid evaporation of gasoline occurs only in connection with gasolines having a 50 percent ASTM distillation point of not greater than about 235 F. Accordingly, this invention relates only to gasolines of this type. While occasional engine stalling may occur as a result of carburetor icing at severe atmospheric conditions of temperature and humidity With gasolines having somewhat higher 50 percent ASTM distillation points, experience has indicated that the problem does not assume major importance except with gasolines of the character indicated. The problem of engine stalling due to carburetor icing is especially severe in connection With gasolines having a 50 percent ASTM distillation point of less than about 220 F. The invention is particularly useful in connection with such gasolines. The term gasoline is used herein in its conventional sense to include hydrocarbon mixtures having a 90 percent ASTM distillation point of not more than about 392 F. and a percent ASTM distillation point of not less than about 140.

As previously indicated, the gasoline compositions of this invention are additionally benefited with respect to non-stalling characteristics by the inclusion therein of a small amount of a lubricating oil having a viscosity at 100 F. of between about 50 and about 500 Saybolt Universal seconds; for example, an oil having a viscosity of about 100 S. U. S./l00 F. can be used with advantage. Although highly parafiinic lubricating distillates can be used, lubricating distillates obtained from Coastal or naphthenic type crude petroleum oils are preferred because of their superior solvent properties. The lubricating oils utilized in the gasoline compositions of this invention can have been solvent-treated, acid-treated or otherwise refined prior to incorporation into the gasoline compositions of this invention. The lubricating distillates referred to are useful in the gasoline compositions of this invention in amounts of from about 0.25 to about 0.75 percent by volume of the composition, for example 0.5 volume percent. In such concentrations these lubricating distillates tend to assist the anti-stalling function of the 0x0 bottoms and in addition function as upper cylinder and valve top lubricants. Greater amounts of the lubricating oil can be used but without appreciable further improvement in the stalling tendencies of the gasoline composition; however, the amount of lubricating oil used should not be so great as to adversely aifect the solubility and combustion characteristics of the ultimate gasoline compositions.

The Oxo bottoms anti-stalling agents of this invention can be incorporated into the base gasoline fuel compositions in any suitable manner. Thus, they can be added as such to gasoline or in the form of a dispersion or solution in solvents such as butanol, isopropanol, ethanol, methanol, 2-butoxyethanol, diethylene glycol monobutyl ether, benzene, toluene, heptane, kerosene, gasoline, mineral oil or the like, which solvents may or may not themselves additionally contribute to the anti-stalling characteristics of the ultimate composition. If desired, the disclosed Oxo bottoms anti-stalling agents can be incorporated in gasoline fuel compositions in admixture with other materials designed to improve one or more properties of the gasoline such as antioxidants, fanti-gumming agents, anti-knock agents, e. g., tetraethyl lead, lead scavenging agents, e. g., ethylene dibromide, ignition control additives, d'e-icing agents, corrosion inhibitors, dyes and the like.

Gasoline compositions of this invention can be further illustrated by the following representative specific examples.

EXAMPLE I Gasoline compositions according to this invention and having reduced engine stalling tendencies were prepared by incorporation in separate samples of a gasoline having a strong tendency as such to promote engine stalling of, respectively, 0.1, 0.25, and 0.5 volume percent of the above-described 327 -730 boiling range Oxo bottoms 6 obtained as still bottoms from the distillation of a C Oxo alcohol product. A typical sample of the base gasoline employed in these compositions had the following inspections:

Gravity, API 64.4 Sp. gr., 60/60 F 0.7223 Anti-knock rating, octane No.2

An additional gasoline composition in accordance with this invention and having reduced engine stalling characteristics can be obtained by admixture of 0.25 volume percent of the 0x0 bottoms of Example I with the base gasoline described in Example I, to which there has been previously added 0.5 percent by volume of an approximately 100 S. U. S./ 100 F. Texas (Coastal) lubricating distillate, a sample of which has the following inspections:

Gravity, API 24.5 Viscosity, SUV, sec.:

70 F 235 100 F 106 130 F 63.9 210 F 38.3 Viscosity index 16 Pour, F M --60 Carbon residue, Conradson, percent 0.02

The foregoing specific embodiments of the compositions of this invention are illustrative, and other suitable compositions within the scope of this invention and having good engine stalling characteristics can be prepared similarly by the substitution in the foregoing examples of other gasolines of the type disclosed herein and tending to promote carburetor icing and by the use of other proportions within the range disclosed herein of the 0x0 bottoms products described in the foregoing examples or other Oxo bottoms products disclosed herein.

As heretofore indicated, the Oxo bottoms anti-stalling agents of this invention produce an appreciable improvement in the stalling characteristics of gasolines that normally tend to promote engine stalling due to carburetor icing. To illustrate the nature of the improvement obtained, in the table following there are presented illustrative results obtained with engine tests using gasoline fuel compositions prepared in accordance with this invention. In order to demonstrate the unusual effectiveness of the 0x0 bottoms anti-stalling agents of this invention, there are also presented in the table below the results obtained with engine tests of a sample of the uninhibited test gasoline.

According to the test procedure followed the fuel compositions to be tested were fed to a standard, 216 cubic inch displacement, 6-cylinder overhead valve Chevrolet engine, the air supply to the carburetor of the engine being obtained by natural aspiration from a cold room atmosphere. The engine was equipped with a standard Carter downdraft carburetor. The ambient temperature of the cold room was 40 F., and the relative humidity was to percent.

The first operating cycle of the engine included, after permitting the engine to cool to the ambient tempera- 7 ture of 40 F., starting the engine and running for 40 seconds at 2000 R. P. M. and then for 20 seconds at 500 R. P. M. (idle) under no load, or until the engine stalls. Repetition of the foregoing cycle 20 times con- 8 amount of oil soluble Oxo still bottoms is about 0.05 to about 1.75 percent by volume of the composition.

4. The composition of claim 1 wherein said small amount of oil-soluble Oxo still bottoms is about 0.2 to

stituted one test. about 1.0 percent by volume of the composition.

Table Composition Concentration, Engine Test, Stalls percent Per Operating Base Fuel Additive by Vol- Cycles ume 10 (avg, 8 tests).

Base Gasoline, 206 F. 50% ASTM Distillation Point (Example I Base Fuel).

0. 1 7 (avg., 3 tests).

0. 3.75 (avg, 4 tests). 0. 5 3.3 (avg., 6 tests).

From the results presented in the foregoing table it will be seen that uninhibited gasolincs having a 50 percent ASTM distillation point in the range disclosed possess poor stalling characteristics. In contrast, an uninhibited gasoline having a 50 percent ASTM distillation point of 240 F. produced an average number of stalls approaching zero in 20 operating cycles. From the foregoing data it is also apparent that gasolines having a 50 percent ASTM distillation point within the range disclosed are markedly improved by incorporation therein of the herein disclosed proportions of the OX0 bottoms anti-stalling agents of this invention.

To the gasoline fuel compositions of this invention there can also be added one or more additional additive agents designed to improve one or more characteristics of the gasoline fuel. For example, antioxidants, anti-knock agents, ignition control agents, other de-icing agents, antirust agents, dyes, lead scavenging agents, anti-gumming agents and the like can be added to the compositions of this invention, and the invention specifically includes gasoline compositions containing such additives.

Numerous additional embodiments of the invention will readily suggest themselves to those skilled in the art. Accordingly, we do not intend to be limited by the foregoing description, but only by the terms of the claims appended hereto.

We claim:

1. A gasoline fuel composition comprising a major amount of a hydrocarbon mixture boiling in the gasoline range that has a 50 percent ASTM distillation point not greater than about 220 F. and that tends to promote stalling of internal combustion engines, and containing a small amount, sufficient to reduce the engine stalling characteristics of the gasoline composition, of oil-soluble Oxo still bottoms obtained by subjecting a mono-olefin containing 6 to 8 carbon atoms to the 0x0 synthesis process by hydroformylating the -mono-olefin with hydrogen and carbon monoxide in the presence of a hydroformylation catalyst to form an aldehydic product having one more carbon atom per molecule than the original monoolefin and then hydrogenating the aldehydic product in the presence of hydrogen and a hydrogenating catalyst to form Oxo alcohols containing one more carbon atom per molecule than the original mono-olefin, and distilling overhead from the reaction products at least the major portion of the Oxo alcohols containing one more carbon atom than the mono-olefin, leaving behind a still bottoms product.

2. The composition of claim 1 wherein the hydrocarbon mixture contains additionally about 0.25 to about 0.75 percent by volume of the composition of a light lubricating oil having a viscosity at 100 F. of about 50 to about 500 Saybolt Universal seconds.

3. The composition of claim 1 wherein said small 5. A gasoline fuel composition comprising a major amount of a hydrocarbon mixture boiling in the gasoline range that has a percent ASTM distillation point not greater than about 220 F. and that tends to promote stalling of internal combustion engines, and containing a small amount, suflicient to reduce the engine stalling characteristics of the gasoline composition, of oil-soluble Oxo still bottoms obtained by subjecting a mono-olefin containing 7 carbon atoms to the OX0 synthesis process by hydroformylating the mono-olefin with hydrogen and carbon monoxide in the presence of a hydroformylation catalyst to form an aldehydic product having 8 carbon atoms per molecule and then hydrogenating the adehydic product in the presence of hydrogen and a hydrogenation catalyst to form Oxo alcohols containing 8 carbon atoms per molecule, and distilling overhead from the reaction products at least the major portion of the 0x0 alcohols containing 8 carbon atoms, leaving behind a still bottoms product, the predominant portion of said Oxo still hottoms boiling above about 378 F. at 760 mm. Hg.

6. A gasoline fuel composition comprising a major amount of a hydrocarbon mixture boiling in the gasoline range that has a 50 percent ASTM distillation point not greater than about 220 F. and that tends to promote stalling of internal combustion engines, and containing a small amount, sufiicient to reduce the engine stalling characteristics of the gasoline composition, of oilsoluble OX0 still bottoms obtained by subjecting a monoolefin containing 7 carbon atoms to the OX0 synthesis process by hydroformylating the mono-olefin with hydrogen and carbon monoxide in the presence of a hydroformylation catalyst to form an aldehydic product having 8 carbon atoms per molecule and then hydrogenating the aldehydic product in the presence of hydrogen and a hydrogenation catalyst to form Oxo alcohols containing 8 carbon atoms per molecule, and distilling overhead from the reaction products at least the major portion of the Oxo alcohols containing 8 carbon atoms, leaving be bind a still bottoms product, said Oxo still bottoms having the following approximate inspections:

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 2 843 463 July 15, 1958 Gardner E0 Gaston et all It is hereby certified that error appears in the-printed. specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 5 line 17 for "less than about 140" read more than about Signed and sealed this 16th day of September 19580 KARL Ho AXLINE ROBERT C. WATSON Commissioner of Patents Attcsting Officer

Claims (2)

1. A GASOLINE FUEL COMPOSITION COMPRISING A MAJOR AMOUNT OF A HYDROCARBON MIXTURE BOILING IN THE GASOLINE RANGE THAT HAS A 50 PERCENT ASTM DISTILLATION POINT NOT GREATER THAN ABOUT 220*F. AND THAT TENDS TO PROMOTE STALLING OF INTERNAL COMBUSTION ENGINES, AND CONTAINING A SMALL AMOUNT, SUFFICIENT TO REDUCE THE ENGINE STALLING CHARACTERISTICS OF THE GASOLINE COMPOSITION, OF OIL-SOLUBLE OXO STILL BOTTOMS OBTAINED BY SUBJECTING A MONO-OLEFIN CONTAINING 6 TO 8 CARBON ATOMS TO THE OXO SYNTHESIS PROCESS BY HYDROFORMYLATING THE MONO-OLEFIN WITH HYDROGEN AND CARBON MONOXIDE IN THE PRESENCE OF A HYDROFORMYLATION CATALYST TO FORM AN ALDEHYDIC PRODUCT HAVINE ONE MORE CARBON ATOM PER MOLECULE THAN THE ORIGINAL MONOOLEFIN AND THEN HYDROGENATING THE ALDEHYDIC PRODUCT IN THE PRESENCE OF HYDROGEN AND A HYDROGENATING CATALYST TO FORM OXO ALCOHOLS CONTAINING ONE MORE CARBON ATOM PER MOLECULE THAN THE ORIGINAL MONO-OLEFIN, AND DISTILLING OVERHEAD FROM THE REACTION PRODUCTS AT LEAST THE MAJOR PORTION OF THE OXO ALCOHOLS CONTAINING ONE MORE CARBON ATOM THAN THE MONO-OLEFIN, LEAVING BEHIND A STILL BOTTOMS PRODUCT.

2. THE COMPOSITION OF CLAIM 1 WHEREIN THE HYDROCARBON MIXTURE CONTAINS ADDITIONALLY ABOUT 0.25 TO ABOUT 0.75 PERCENT BY VOLUME OF THE COMPOSITION OF A LIGHT LUBRICATING OIL HAVING A VISCOSITY AT 100*F. OF ABOUT 50 TO ABOUT 500 SAYBOLT UNIVERSAL SECONDS.