US 3756793 A
Description (OCR text may contain errors)
United States Patent 3,756,793 FUEL COMPOSITION Isaac C. H. Robinson, Chester, England, assignor to Shell Oil Company, New York, N.Y.
No Drawing. Filed June 9, 1971, Ser. No. 151,505 Claims priority, application Great Britain, June 16, 1970, 29,142/70 Int. Cl. C101 1/22 US. Cl. 44-62 3 Claims ABSTRACT OF THE DISCLOSURE Detergent/dispersant properties are imparted to liquid hydrocarbon fuels containing minor amounts of (A) a polyamine which is the reaction product of a halohydrocarbon having an average molecular weight between 600 and 2500 and an alkylenepolyamine and (B) an organic substance having a viscosity between 20 and 2500 cs. at 20 C.
BACKGROUND OF THE INVENTION The regulation and the enforcement of air pollution requirements for motor vehicles containing gasoline or diesel engines is becoming increasingly less tolerant. One means of combating air pollution as well as conforming to air pollution regulations is to reduce the emission of hydrocarbons from these types of engines. In gasoline engines, for example, hydrocarbon emissions are due, inter alia, to crankcase ventilation. This ventilation is necessary to prevent dilution and contamination of the lubricating oil by unburnt or partly burnt gasoline components leaking from the combustion chamber along the piston and cylinder walls into the crankcase. The crankcase is ventilated by a forced draft, as a result of which, components known as blow-by gases find their way into the atmosphere. To reduce this type of emission some engine manufacturers have provided the engine with a means for returning the mixture of blow-by gases and air to the inlet system preceding the carburetor, for instance, to the air filter. This measure, however, causes fouling of the fuel and inlet system, which, in turn causes the engine to malfunction, which in turn tends to increase the concentration of unburnt and partly burnt hydrocarbons in the exhaust gases.
It is possible to counteract fouling of engine parts by incorporating a minor amount of a compound with detergent properties into the fuel. However, to increase engine performance these compounds in the past have been added to fuels in association with relatively viscous mineral oil constituents which have a tendency to break down under the high engine operating temperatures. Thus such a detergent combination itself may give rise to increased amounts of noxious compounds being emitted along with p the exhaust gases into the atmosphere.
THE INVENTION This invention deals with a fuel composition that effectively counteracts the fouling of gasoline and diesel engines without adding an additional source of potential atmospheric pollution to the combustion environment. Moreover, the composition of the invention when used in, for example, gasoline engines, counteracts both fouling of the carburetor and other parts of the inlet system, such as positive crankcase ventilation valves, inlet valves and inlet valve rods, thereby reducing the amount of noxious compounds, such as carbon monoxide and unburnt or partly burnt hydrocarbons and other compounds stemming from the fuel and/ or the lubricating oil which leave via the exhaust system.
The fuel compositions of this invention are of particular importance today in this era of no-lead or low-lead gasolines, since with their use good inlet system cleanice liness and good engine performance may still be obtained even if the gasoline does not contain agents which improve the ignition, such as tetraethyllead and/or tetramethyllead, and scavengers, such as ethylene dibromide and/or ethylene dichloride. Furthermore, the fuel compositions according to the invention may comprise relatively large amounts of non-hydrocarbon combustible compounds. For example, gasoline compositions according to the invention may contain up to 50% v. of ethers, in particular ethers with a branched hydrocarbon chain such as di-isopropylether and methyl tert.butylether, which have a beneficial influence on the octane number of the gasoline compositions. Thus this invention particularly deals with fuel composition additives that (1) promote engine cleanliness and the reduction of atmospheric pollution by reducing engine deposits and exhaust emissions without the use of substances which are themselves sources of noxious emissions and (2) by their adaptability to no-lead, low-lead or ether type fuels allow the use of fuels which also effectively remove the risk of lead as a pollutant and which allow the use of higher octane fuels while maintaining good engine performance.
The invention therefore relates to a fuel composition consisting essentially of a major amount of a liquid hydrocarbon fuel and a minor detergent/ dispersant amount of (A) a polyamine reaction product of a polyisobutenylchloride with an average molecular weight between 600 and 2500 and an alkylenepolyamine having the general formula H-N- RN R l l).
in which R independently is H or CH R is a C alkylene radical, and n is a whole number from 1 to 5 inclusive and (B) an organic substance with a viscosity between 20 and 2500 cs. at 20 C., consisting essentially of a polymer or copolymer or mixtures thereof with an average molecular weight between 300 and 5000 selected from the group consisting of hydrocarbons, substituted hydrocarbons containing oxygen and substituted hydrocarbons containing oxygen and nitrogen.
The fuel compositions according to the invention may consist of any liquid fuel, in particular fuels obtained from mineral oils. They may be residual fuels but preferably are distillate fuels such as gasoline, diesel fuel, aviation fuel, gas oil and the like.
The term distillate fuels not only comprises fuels obtained by distillation of a mineral oil or a mineral oil fraction, but also fuels which have been obtained by conversion processes of a mineral oil, such as alkylation, isomerization, polymerization, thermal and catalytic cracking, reforming processes, e.g., platforming, hydrotreating, hydrocracking and the like, and have a boiling range comparable to that of fuels obtained by distillation of a mineral oil per se. In general the boiling point of a distillate fuel will be at most about 350 C. at atmospheric pressure. The preferred distillate fuels are aviation turbine fuel and gasoline. Aviation turbine fuel as defined herein is a hydrocarbon oil having a Reid vapor pressure below three pounds per square inch at F. and a final boiling point below 325 C. Gasoline as defined herein is a mixture of hydrocarbons having a boiling range determined according to ASTM Method D 86 between about 30 C. and 210 C.
The polyamines (Additive A) which according to the invention are incorporated into the fuel compositions are the product of a reaction between a polyisobutenylchloride having an average molecular weight between 600 and 2500 and preferably between 800 and 2000 and an alkylenepolyamine.
Examples of alkylenepolyamines suitable for the reaction are ethylene-1,2-diamine, propylene 1,2 diamine,
propylene-1,3-diamine, N,N-dimethyl-propylene-1,3 diamine, and ethylene and propylene polyamines, such as diethylenetriamine, triethylenetetraamine and tetraethylenepentamine or mixtures thereof. Tetraethylenepentamine is particularly preferred.
The polyamines according to the invention may be prepared, for instance, by allowing a suitable polyamine to react with the halogen-containing hydrocarbon. The halogen-containing hydrocarbon, that is, polyisobutenylchloride, may be prepared in any convenient manner. A convenient method is to halogenate the polyisobutene with molecular halogen without a solvent or in solution. The reaction between the polyisobutenylchloride and the alkylenepolyamine is typically carried out at a temperature between and 200 C., preferably in the presence of an inert solvent or diluent such as benzene, toluene, xylene, hexane, heptane or mixtures of such hydrocarbons as fractions of mineral oils. The reaction time will, of course, vary with ambient and reaction conditions but will usually require less than 24 hours. The molar quantities of the reactants depend upon how many hydrocarbon groups derived from the polyisobutenylchloride it is desired to introduce to the alkylenepolyamine. For example, if the polyamine is N,N-dimethylpropylene-1,3-diamine, one mole of the chlorohydrocarbon is reacted per mole of the diamine; however, if the amine is tetraethylenepentamine about 3 moles of the chlorohydrocarbon are reacted per mole of tetraethylenepentamine. Preferably, the molar quantities of the reactants are controlled in such a manner that the amine products contain on the average up to 4 hydrocarbon radicals originating from the halogen-containing hydrocarbon per molecule.
During the reaction hydrogen chloride is liberated when the hydrocarbon radical from the polyisobutenylchloride is coupled to the alkylenepolyamine, usually combining with the amine starting material. In order to prevent this undesirable reaction, the reaction between the alkylenepolyamine and the polyisobutenylchloride is preferably carried out in the presence of a basic substance as hydrogen-halide acceptor which differs from both the amine that is used as starting material and the polyamine to be formed which is a stronger base than either, and which is preferably not an amine. carbonates, bicarbonates, oxides and hydroxides are used for this purpose. Alkalimetal compounds such as sodium carbonate and potassium carbonate are preferred hydrogen-halide acceptors.
A wide variety of compounds or substances are suitable as the organic substance having a viscosity between 20 and 2500 cs. at 20 C. (Additive B). Polyamines other than the polyamines disclosed hereinabove as Additive A are suitable for use as the Additive B. Also suitable as Additive B are amides, esters or mixtures of ester used as synthetic lubricants; for example, aliphatic diesters of dibasic aliphatic carboxylic acids having from 6 to 20 carbon atoms and aliphatic monohydric or polyhydric alcohols having from 1 to 12 carbon atoms such as esters of adipic, azelaic and sebacic acid and heptyl alcohol, propylene glycol and pentaerythritol, and also esters of monocarboxylic acids having from 4 to 18 carbon atoms in a molecule, such as esters of caprylic acid and monohydric or polyhydric alcohols having from 2 to 18 carbon atoms in the molecule as Z-ethyl-hexyl alcohol and glycerol.
Although these substances are suitable for use as the Additive B, the preferred materials for use as Additive B are polymers or copolymers or mixtures thereof with an average molecular weight between 300 and 5000 and are suitably hydrocarbons, substituted hydrocarbons containing oxygen, or substituted hydrocarbons containing oxygen and nitrogen. Exemplary of the hydrocarbon polymers are polyisobutylene, poly-alpha-alkyl styrenes, e.g., polyalpha-methyl styrene, block polymers of polystyrenes and polydienes such as polybutadiene and polyisoprene, and t e ike. Representative f the Substituted hydrocarbons containing oxygen are polyesters, polyetherglycols and copolymers and mixtures thereof.
A useful class of the above-mentioned polyesters includes polyalkyl acrylates and polyalkyl methacrylates. The polyalkyl acrylates and polyalkyl methacrylates may contain lower alkyl groups with one to seven carbon atoms such as methyl or ethyl groups, and also higher alkyl groups with from 8 to 22 carbon atoms such as octyl, dodecyl, or octadecyl. Branched alkyl groups, such as tertiary butyl groups, are also suitable. Copolymers of acrylates and/ or methacrylates with different alkyl groups can also be used.
The most preferred type of polymeric compounds for Additive B are the polymers of substituted hydrocarbons containing oxygen of the group consisting of polyalkylene oxides, such as polyethylene oxide, polypropylene oxide, polybutylene or copolymers thereof, such as copolymers of propylene oxide and ethylene oxide. A particularly preferred group of polyalkylene oxides to be used in the fuel compositions of the invention are those having molecular weight between 1000 and 2500. The polyalkylene oxides may be conveniently prepared by polymerizing alkylene oxide in the presence of a catalyst, for example, an acid catalyst, such as boron trifiuoride, by a basic catalyst such as a hydroxide or an alkoxide of an alkali metal is preferable. However, a basic catalyst is used in the presence of an initiator, such as water or a monohydric alcohol. These initiators may contain other polar groups, e.g., one or more amine groups; in the latter case, polyalkylene oxides are obtained which contain one or more amine groups. Polyalkylene oxides which contain at least one hydroxy group may be further reacted, that is, esterified or etherified, before being utilized in the invention.
A most highly preferred group of polymers of substituted hydrocarbon containing oxygen are the polyether glycols. These may be obtained by polymerizing one or more alkaline acids in the presence of a basic catalyst and in the presence of water or a glycol as an initiator. Polyoxypropylene glycol, obtained by polymerization of propylene oxide in the presence of Water as initiator, is particularly preferred. Another group of useful polymers of substituted hydrocarbons containing oxygen includes block polymers or copolymers. For example, homo or heteric copolymers of oxypropylene and oxyethylene glycol in a weight ratio range of from about 75:25 to about 25:75, and preferably 1:1, may be used with advantage.
Exemplary of the polymeric materials of substituted hydrocarbons containing oxygen and nitrogen useful as Additive B are the above-mentioned polyalkylene oxides containing one or more amine groups. Another such group is obtained by incorporation of polar monomers such as N- vinylpyrrolidone, 4-vinylpyridine, 2-methyl-5-vinylpyrrolidone, and the like, in the above-mentioned polyacrylates and polymethacrylates by copolymerization of these polar monomers with the alkylacrylates or alkylmethacrylates.
The concentration of each of the additives according to the invention in the fuel compositions may vary between the wide limits. In general, the fuel compositions will contain from about 0.001 to about 0.1% by weight of the total fuel composition of each of the additives. Since the additives are soluble in the fuel compositions within the scope of the invention, they may be added to the fuel as such but preferably they are added in the form of a concentrate. Such concentrates contain, besides the additives, at least one liquid which is a solvent for the additive and may contain mixtures of solvents. Suitable solvents are hydrocarbons such as butanol, pentanol or hexanol; optionally, mineral oil substituents such as spindle oil, or a light or medium machine oil, may be part of the solvent. In general, however, heavy oils such as bright stock should not be used, since they may give rise to air pollution due to their incomplete combustion in the engine. The concentrates will normally contain between about 5 and about wt. and in particular between about and about 70% wt. of the additives of the invention.
In addition to the fuel and a minor amount of the additives, the fuel compositions of the invention may contain minor amounts of other substances by which the quality of the fuel is further improved, such as agents for improving the ignition, scavenging ageuts, anti-icing agents, antioxidants, conductivity improving agents, metal deactivating agents, phosphorus compounds and the like.
EXAMPLE I The gasoline compositions were tested according to A Bench Technique for Evaluating the Induction System Deposit Tendencies of Motor Gasolines, described by A. A. Johnston and E. Dimitrotf in The Society of Automotive Engineers (SAE) Paper No. 660783, to comparatively evaluate the inventive compositions, and compositions not within the scope of the invention. A tube temperature of 240 C. was used. The amount of deposit (in mg. per 100 ml. gasoline composition sprayed upon the tube) was determined after the tube at the end of each experiment had been washed with heptane. 'An N,N-dimethyl-N-polyisobutenylpropylene diamine (Additive A) with a molecular weight of 1350 and polyisobutenyl group containing 90 carbon atoms, a polyoxypropylene glycol (Additive B) with a molecular weight of about 1500 and a viscosity of 304 cs. at 20 C. were added in amounts shown in the table below to a premium grade gasoline, which contained 400 p.p.m. of an anti-icing additive consisting primarily of dipropylene glycol, and 250 p.p.m. of a 20 W/ 50 motor oil. The 20 W/50 motor oil was present in the gasoline in order to give a measurable amount of deposit in the test when no additives according to the invention were present in the gasoline. The table shows the results.
TABLE Additives (p.p.m.) Deposit, Experiment; mg./100 ml. number Additive A Additive B gasoline In Experiment 4 the gasoline composition is according to the invention; Experiments 1, 2 and 3 are for comparison only. As will be seen from the table, the amount of deposit obtained with the gasoline composition of the invention is much lower than the amounts obtained in the comparative experiments.
EXAMPLE II In order to evaluate the additives under actual engine conditions a premium gasoline, which contained 100 p.p.m. of the N,N-dimethyl-N'-polyisobutenylpropylene diamine as described in Example I and 350 p.p.m. of the polyoxypropylene glycol as described in Example I, was tested in a Sunbeam Talbot engine. In this test the general condition of the inlet system as regards fouling is determined on the basis of the extent to which fouling of the inlet valves and the inlet valve rods occurs. The test is carried out on a Sunbeam Talbot engine with a piston displacement of 2264 cm. a compression ratio of 6.45:1, and a maximum capacity of brake horsepower at 4000 r.p.m. Before the test was started, the engine, including the two carburetors, was cleaned whereupon the engine was kept in continuous operation for 32 hours at a speed of 1500 r.p.m., a capacity of 15 brake horsepower and a fuel consumption of 5.0 kg. per hour. After the test had been finished, the fouling of the inlet valves and the inlet valve rods was evaluated.
The cleanliness of the inlet system showed an improvement of 93% over the cleanliness obtained with the same premium gasoline without the additives according to the invention. For comparison the same premium gasoline containing ppm. of the N,N-dimethyl-N-polyisobutenyl propylene diamine and no polyoxypropylene glycol was tested. The cleanliness of the inlet system in this case showed an improvement of 91% over the cleanliness obtained with the premium gasoline only.
Other disclosed compositions not exemplified in the above examples, give equivalent, although not identical results.
What is claimed is:
1. Gasoline containing (A) from about 0.001 to about 0.1% by weight of a polyamine reaction product of a polyisobutenylchloride with an average molecular weight between 800 and 2000 and N,N-dimethylpropylenediamine and (B) from about 0.001 to about 0.1% by weight of a polyether glycol having an average molecular weight between 300 and 5000 and a viscosity between 20 and 2500 cs. at 20 C.
2. The gasoline composition of claim 1 in which the polyether glycol is polyoxypropylene glycol.
3. The gasoline composition of claim 1 in which the polyether glycol is a copolymer of oxyethylene and oxypropylene glycol in a 1:1 weight ratio.
References Cited UNITED STATES PATENTS 3,438,757 4/1969 Honnen et al 44-72 3,565,804 2/ 1971 Honnen et al. 4472 3,336,124 8/ 1967 Dunworth 44-62 3,264,216 8/ 1966 Rockett 44-62 3,004,837 10/1961 Riemenschneider 4462 3,037,851 6/ 1962 Scheule 44-62 DANIEL E. WYMAN, Primary Examiner Y. H. SMITH, Assistant Examiner US. (:1. X.R. 44-72