US3342570A

US3342570A - Detergent gasoline composition containing 2-amino straight-chain alkanes

Info

Publication number: US3342570A
Application number: US373509A
Authority: US
Inventors: George J Kautsky
Original assignee: Chevron Research and Technology Co
Current assignee: Chevron USA Inc
Priority date: 1964-06-08
Filing date: 1964-06-08
Publication date: 1967-09-19
Anticipated expiration: 1984-09-19
Also published as: FR1437041A; DE1289354B; GB1066562A

Description

United States Patent Ofifice ABSTRACT OF THE DISCLOSURE Leaded gasoline composition containing secondary attached straight-chain alkyl primary amines having from about 9 to 24 carbon atoms in the alkyl group.

This invention relates to improved detergent gasoline compositions for spark ignition internal combustion engines. More particularly, the invention concerns gasoline compositions containing new detergent additives which substantially reduce carburetor deposits in spark ignition internal combustion engines.

In the operation of spark ignition internal combustion engines there have been problems of rough idling and engine stalling, and carburetor adjustments and reconditioning are often necessary to provide satisfactory service. It 'is found, particularly in the case of stop-and-go driving in metropolitan areas, that such stalling and idling problems are more frequent, especially in the case of multithroat carburetors of the type employed in many present-day automobiles. It has been determined that the rough idling and engine stalling are primarily due to the accumulation of deposits in the throttle body section of the carburetors. As the deposits build up, the amount of air for given amount of fuel is impeded and greatly reduced, and the air-fuel mixture is overly rich for satisfactory engine operation. Frequent adjustments of the carburetor are needed to overcome the effect of this deposit buildup, and finally it becomes necessary to replace the carburetor or give it a complete overhaul.

. Various additives have been suggested for use in gasoline to cut down on the buildup of carburetor deposits. However, such additives have usually sufiered certain disadvantages as to overall effectiveness, and the search has continued for more suitable compositions.

It has now been found that deposits in the carburetors of spark ignition internal, combustion engines are substantially reduced by an improved detergent gasoline composition comprising a major proportion of a hydrocarbon base fuel boiling in the gasoline boiling range and from about 00001 to 1.5% by weight of branched-chain alkyl primary amine having from about 9 to 24 carbon atoms in the alkyl group.

The branched-chain alkyl primary amines of the gasoline"cornpositions of the invention are characterized by the formula CHNH:

in which one of the branches, R is a straight-chain alkyl group of from 1 to 4 carbon atoms and the other branch, R is a straight-chain alkyl group of to 22 carbon atoms. Such amines may also be described as aminoalkanes, that is, Z-aminoalkane, 3-aminoalkane or 4-aminoalkane in which the alk-ane is straight-chain and contains 9 to 24 carbon atoms.

3,342,570 Patented Sept. 19, 1967 Although the branched-chain alkyl primary amine is satisfactorily employed in any amounts sufficient to impart detergency to the gasoline composition, it is preferred that it be present in the gasoline in amounts from about 0.0001 to 1.5% by weight. For present purposes, amounts in the range from about 0.003 to about 0.03% by Weight are most satisfactory from the standpoint of elfectiveness and cost.

To facilitate handling, it is customary to formulate the improved detergent additives of this invention as concentrates. Since the additives are unusually stable and possess good solubility characteristics, these concentrates represent a particular embodiment of the invention. In the preparation of the concentrate, the detergent additive is dissolved in a suitable hydrocarbon or alcohol solvent boiling in the range from about 150 to 400 F., preferably an aromatic hydrocarbon solvent such as benzene, toluene, xylene, or higher boiling aromatics or aromatic thinners. Aliphatic alcohols of about 3 to 8 carbon atoms, such as isopropanol, isobutylcarbinol, n-butanol and the like, as well as mutually compatible mixtures of such alcohols and hydrocarbon solvents, are also suitable for use with the detergent additive. The amounts of detergent additive in the concentrate are ordinarily at least 10% by weight, and may vary up to about 70% by weight.

In addition to the detergent additive, other fuel additives may be used in the gasoline compositions of the invention. The deposit-reducing benefits are obtained in combination with lead alkyl antiknock agents, such as tetramethyl lead or tetraethyl lead. Such antiknock agents are ordinarily employed in amounts sufiicient to enhance the octane number, usually from about 0.5 to 4 ml./gal.

A nonvolatile light mineral lubricating oil, suchas petroleum spray oil, is also a suitable additive for the gasoline compositions of the invention. These oils are believed to act as a carrier for dispersed deposits. They are employed in amounts from about 0 .05 to 0.5% by to haloalkanes volume based on the final gasoline composition.

The branched-chain alkyl primary amine detergent additive is available from a number of sources. For example, straight-chain olefinic hydrocarbons of the desired chain length may be converted by conventional methods having halogen in the 2-, 3- or 4- positions, and the resulting haloalkanes may then be treated with ammonia to give the corresponding branched-chain alkyl amine. The olefins also may be reacted with concentrated: (-95%) sulfuric acid,

then reacted with hydrocyanic acid, hydrolyzed with water and treated with an excess of aqueous caustic to give the amine. lOlefins may be reacted with nitrogen oxide compounds, for example, nitrogen tetroxide (N 0 in ether solution to give a mixture of nitronitrites, dinitroalkanes and nitronitrates which, in the presence of base on heating, are converted to nitroalkenes, which are then hydrogenated to the corresponding aminoalkanes. Suitable aminoalkanes in general are also available from unsaturatedaliphatic hydrocarbons by the so-called Ritter reaction as set forth in Ritter US. Patent No. 2,573,673, issued October 30, 1951.

In accordance with the present invention, a preferred.

class of branched-chain alkyl primary amines and mix tures thereof is obtained by converting cracked wax olefins to the corresponding haloalkanes and aminoalkanes.

The cracked wax olefins contain from about 9 to 24 carbon atoms, and preferably from about 12 to 18 carbon atoms. Mixtures of cracked Wax olefins obtained by the thermal cracking of paraflin waxes are particularly suitable. Such mixtures and their preparation are described in various publications, including U.S. Patent No. 2,172,- 228 on Process for the Manufacture of Olefins. The primary amines produced from these olefins have the amino group attached to the branched-chain alkyl at the 2-, 3- or 4- positions to provide a mixture of branchedchain alkyl groups, i.e., secondary alkyl groups.

As an illustration of a suitable method of preparing particular branched-chain alkyl primary amines in accordance with the invention, a mixture of alkyl chlorides is first prepared by hydrochlorination of the thermally cracked wax olefin mixture containing from about 15 to 20 carbon atoms per molecule. This gives a mixture of secondary alkyl chlorides or 2-, 3- and 4-chloroalkanes, as they are otherwise termed. One mole of the alkyl chlorides thus obtained is reacted with from about 10 to 20 moles of ammonia at about 160 C. under autogenous pressure in an autoclave. Reaction time is about 10 hours. The product is washed with caustic and then with water. The yield is 80% primary amines, 4% secondary amines, olefins and 11% unconverted alkyl chlorides. The olefins and unconverted alkyl chlorides are removed and recycled as desired.

. The improved gasoline compositions containing the I branched-chain alkyl primary amines in accordance with the invention provide excellent detergent performance compared to gasoline compositions containing other alkyl amines. Such detergent properties are determined by the generally accepted method of appraising the gasoline compositions in the glass throttle body engine test, which has been especially developed to observe and to evaluate deposits in the carburetors of typical gasoline engines.

In the Glass Throttle Body Test, a 6-cylinder Plymouth automobile engine is set up in the laboratory and is provided with a conventional carburetor modified by the replacement of the metal throttle body section by a removable glass throttle body section. This glass throttle body is a section of glass tubing A" thick, of approximately 1% outside diameter and about 1% long. An automatic cycler or timer, which consists of a constantspeed electric motor and a magnetic clutch, is provided for insuring cyclic operation of the engine with 7.5 min. idle periods followed by five accelerations to 2000 r.p.m. Crankcase fumes are vented to the'carburetor air inlet, since these fumes are now known to be responsible for the larger portion of the deposits. The engine is started up, using leaded gasoline containing a conventional amount of tetraethyl lead (1.5 ml./gal.), but no surfaceactive additives of any kind. It is run for 4 hours with the blowby fumes being drawn in at the air intake. The engine is then stopped, the glass body is removed, and both sides of it are photographed. Thereupon the dirty glass body is again installed on the engine and run for one hour on the same leaded base gasoline compounded with the detergent-action additive. This time the blowby fumes are not piped to the carburetor. After the run is completed, the glass throttle body is again photographed, and the effectiveness of the detergent-containing gasoline (the percentage of cleanup of deposits) is visually estimated.

In these tests, branched-chain alkyl primary amine mixtures obtained from C C cracked wax olefins as described above were evaluated in the gasoline composition at a concentration of 0.003% by weight. They were found to give a carburetor cleanup of up to 76%, whereas a typical straight-chain amine, namely, oleyl amine, gave a cleanup of only 57%.

In further tests, the oxidative stability of the branchedchain alkyl primary amines of the invention was determined in comparison to similar straight-chain l-aminoalkanes. In these tests, 0.5 g. of l-amino C C alkanes obtained from cracked wax olefins was heated on an aluminum planchet open to the atmosphere for 24 hours at 130 C. 0.4 g. was lost by evaporation. The residue weighed 0.1 g. It was dissolved in mixed aqueous-organic solvent and titrated with acid. The residue was found to contain no base. By way of comparison, the corresponding branched-chain alkyl primary amine gave a residue of 0.1 g. which, upon titration, was found to contain 0.2 mm. of base. The result of this test shows that at 24 hours at C. in the presence of air there was still present 55.5% of the original base of the branched-chain alkyl primary amine, while, on the other hand, the l-aminoalkane analog has been completely decomposed.

The loss of base of the detergent additives as indicated above was further studied. The additives were blended into white oil and heated at 230 F. and at 300 F. The oil was inhibited with 4,4-methylene bis-(2,6-dit-butylphenol) against oxidation. It was found that after 24 hours at 230 F., the branched-chain alkyl primary amines obtained from C C cracked wax olefins lost only about 13% of the basic nitrogen, whereas the l-aminoalkane analogs and oleyl amine lost about 30% of the basic nitrogen under the same conditions. At 300 F., the decomposition occurs at a much faster rate, and in 8 hours about 40% of oleyl amine is decomposed while only about 8% of the branched-chain alkyl primary amine decomposed by a loss of basic nitrogen.

In the foregoing illustrations of the invention, the effectiveness of amines derived from mixtures of olefins, such as thermally cracked wax olefin fractions, is particularly apparent. The typical C -C olefins which were employed have the following weight composition:

Percent n 0-6 C 11.2 C 19.3 17 18.5 C 18.4 C 17.3 C 14.0 C 0.7

Such a mixture contains about 92% by weight of straightchain wolefins, 3% a,w-diOl6finS, 3% internal olefins and 2% branched-chain, naphthenic and other hydrocarbons. In the hydrohalogenation of these olefins a catalyst, such as ferric chloride, is conveniently employed to direct the addition such that the halogen atom attaches to nonterminal carbon atoms, thereby providing the branchedchain alkyl structure for the amine final product. The hydrohalogenation is also customarily carried out at temperatures, such as 30 to 40 C., which are not high enough to cause rearrangement of the olefin double bond. The 2-, 3- and 4-haloalkanes thus obtained are readily converted to amines by conventional procedures as previously indicated. 1

While the character of this invention has been described in detail with numerous examples, this has been done by way of illustration only and without limitation of the invention. It will be apparent to those skilled in the art that numerous modifications and variations of the illustrative examples may be made in the practice of the invention within the scope of the following claims.

I claim:

1. An improved detergent gasoline composition comprising a major proportion of a hydrocarbon base fuel boiling in the gasoline boiling range, lead alkyl antiknock agent in amount suflicient to enhance the octane number and froma about 0.0001 to 1.5 percent by weight of branched-chain alkyl primary amine having from about 9 to 24 carbon atoms in the alkyl group of the formula:

in which one of the branches, R is a straight-chain alkyl group of from 1 to 3 carbon atoms and the other branch,

3,342,570 5 6 2. The composition of claim 1 in which the branchedto 75 percent by weight of the branched-chain alkyl prichain alkyl group of the structural formula denoted by: mary amine of the gasoline composition of claim 1.

RI References Cited 5 UNITED STATES PATENTS 1,787,789 1/1931 Lovell et al. 44-72 1,954,939 4/1934 Magness 44-80 is derived from thermally cracked wax olefin mixtures 2,684,292 7/1954 Caron et a1 44*72X having about 15 to 20 carbon atoms per molecule.

3. An improved detergent gasoline concentrate conm DANIEL WYMAN Primary Examiner sisting essentially of a hydrocarbon solvent and from 10 Y- H- SMITH, s stant Ex miner.

Claims

1. AN IMPROVED DETERGENT GASOLINE COMPOSITION COMPRISING A MAJOR PROPORTION OF A HYDROCARBON BASE FUEL BOILING IN THE GASOLINE BOILING RANGE, LEAD ALKYL ANTIKNOCK AGENT IN AMOUNT SUFFICIENT TO ENHANCE THE OCTANE NUMBER AND FROM ABOUT 0.0001 TO 1.5 PERCENT BY WEIGHT OF BRANCHED-CHAIN ALKYL PRIMARY AMINE HAVING FROM ABOUT 9 TO 24 CARBON ATOMS IN THE ALKYL GROUP OF THE FORMULA: