US3838991A - Gasoline compositions containing bisamide additives - Google Patents

Abstract

Disclosed herein are gasoline fuel compositions for internal combustion engines containing therein from about 0.003 to 0.02 percent by weight of a bisamide having the formula

WHEREIN Ac is an aliphatic acyl group of 8 to 20 carbon atoms, R is hydrogen or an alkyl group of 1 to 4 carbon atoms, R'' is an alkyl group of 1 to 4 carbon atoms, N IS 2 OR 3 AND X IS 1 TO 3. Also disclosed are bisamide/hydrocarbon solvent concentrates.

Description

United States Patent 1 Garth [451 Oct. 1,1974

1 GASOLINE COMPOSITIONS CONTAINING BISAMIDE ADDITIVES {75] Inventor: Bruce Hollis Garth, Newark, Del.

[73] Assignee: E. I. du Pont de Nemours and Company, Wilmington, Del.

22 Filed: Dec. 1, 1972 21 Appl. No.: 311,396

[52] US. Cl 44/66, 44/71, 44/DIG. 001 [51] Int. Cl C101 1/18 [58] Field of Search 44/DIG. l, 66, 71

[56] References Cited UNITED STATES PATENTS 2,956,020 10/1960 Suprin et a1. 44/66 X 3,157,477 11/1964 Emrick 44/D1G. 1 3,169,980 2/1965 Benoit 44/66 X 3,336,123 8/1967 Crile 44/66 X Primary Examiner-Daniel E. Wyman Assistant ExaminerAndrew H. Metz Attorney, Agent, or Firm.lames A. Costello [5 7] ABSTRACT Disclosed herein are gasoline fuel compositions for internal combustion engines containing therein from about 0.003 to 0.02 percent by weight of a bisamide having the formula 7 Claims, N0 Drawings GASOLINE COMPOSITIONS CONTAINING BISAMIDE ADDITIVES BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to gasoline compositions comprising gasoline plus an additive which is a bisamide compound containing a nonterminal tertiary amine group.

2. Description of the Prior Art Additives for gasoline have been proposed in the art to minimize the formation of harmful deposits in the carburetor or to reduce the amount of the deposit already formed. Such additives, commonly known as gasoline detergents include carboxylic aminoamides, salts of aminoamides, and amine phosphates.

An additive to be useful in gasoline as a carburetor detergent, in addition to being effective in minimizing the formation of the deposits in the carburetor, should be effective in reducing the amount of deposits already present in the carburetor; and should show minimal water interaction such as entrainment of water into gasoline or the formation of water emulsions. Additionally, it is also essential that an additive to gasoline should not contribute to atmospheric pollution or be detrimental to any pollution control device.

The aminoamides and the salts of aminoamides described above are not used extensively because of their limited utility as carburetor detergents or their poor water interaction properties. The various amine phos phates are effective gasoline detergents but the presence of phosphorus is considered to be harmful to the efficient operation of automotive exhaust gas-treating devices such as thermal reactors or catalytic mufflers.

SUMMARY OF THE INVENTION This invention concerns a gasoline composition having a major portion of hydrocarbons boiling in the gasoline range, and from about 0.003 to 0.02 weight percent of a compound of the formula wherein Ac is an aliphatic acyl group of 8 to carbon atoms,

R is selected from the group consisting of hydrogen and alkyl groups of 1 to 4 carbon atoms,

R is an alkyl group of 1 to 4 carbon atoms,

n is 2 or 3 and x is l to 3. Preferred concentrations of the bisamide additive are between about 0.004 to 0.008 weight percent Higher concentrations can be used but provide no correspond ing increase in detergency and may be harmful to the water interaction properties of the gasoline compositions. Preferred compositions are those in which the value of n is 3 and the value of x is l. The most preferred composition for best results is methyliminobis(- propyloleamide),

. CH3 ll H l H ll The additives of this invention are bisamides of polyamines wherein the nonterminal nitrogens are tertiary nitrogens i.e.. tertiary amino groups. The novel gasoline composition is effective in minimizing formation of deposits in the carburetor. in reducing the deposits already present in the carburetor, in providing anti-icing. anti-stalling protection and has satisfactory water interaction characteristics. The bisamide-forming reactions to be described later are preferably carried out in the presence of a hydrocarbon solvent such as benzene. toluene or xylene and the like. The bisamide products, at concentrations of from about 10 to weight percent in such solvent components, are conveniently handied for facile addition to the fuells. Such concentrates of about 10 to 70 weight percent of the hereindescribed bisamides in hydrocarbon solvents are included within the scope of this invention.

That the novel gasoline compositions have anti-icing properties is surprising since it is generally considered that-amides are ineffective as anti-icing additives. For example, in U.S. Pat. No. 3,336,123 it is pointed out that monoamides such as N(3-dimethylaminopropyl )stearamide. N( 3-dimethylaminopropyl tallamide and N--(3-dibutylaminopropyl)oleamide have little or no effect in suppressing carburetor icing.

DETAILS OF THE INVENTION The polyamines useful for the preparation of the bisamide additive compounds have the general formula R! l H- T( nH2nN )xCaH2nIIIH R R wherein R is a hydrogen or an alkyl group of l to 4 carbon atoms,

R is an alkyl group of l to 4 carbon atoms,

11 is 2 or 3 and x is l to 3.

The polyamines are polyethylene (or propylene) polyamines wherein the nonterminal nitrogens are all present as tertiary amino groups. Representative poly amines suitable for the preparation of the bisamide additive compounds include H NCH CH N(CH H NCH CH N(C H )CH CH NH H NCH CH N(C H )CH CH NH H NCH CH N(C H )CH CH NH 2 2 2 H3))2C 2 2 2w 2 H2 2 3))3 2 2 2 2 2 2 2 5))2 z -1N 2, 2 H2 2 2 5))3 2 2 2- CH NHCH CI-I N(CH )CH CH NI-I CH NHCH CH N(CH )CH CH NHCI-I H NCH CH CH N(CH )CH CH CH NH H- NCH CH CH N(C H )CH CH lCH NH H NCH CH CHI MC H )CH CH CH NH H NCH CH CH MC HE,)CH CI-I CH NH 2 2 2 z 3))2H2 2 H2NH2, 2 2 2 2 3))3 z 2 H2 H2, HQM z QM Z Q)2 z Hz H2 2 CH NHCH CH CH MCPL,)CH CH CH NHCH and the like. The preferred polyamine is H NCH CH CI-I N(CI-I )CH CI-I CH NH Many of the above polyamines are available commercially while the others can be prepared by art-known procedures.

The acyl portions of the bisamides, represented by Ac in the general formula for the bisamide, are derived from monobasic aliphatic fatty acids containing 8 to 20 carbon atoms such as caprylic, pelargonic, capric, lauric, myristic, palmitic, margaric, stearic, oleic, linoleic, nondecylic and arachidic. The readily available technical grades of these acids, which usually contain small amounts of homologs, are advantageously used instead of rigorously purified individual acids. For improved handling, up to about percent by weight of C to C fatty acid can also be present. The preferred acid is oleic acid,

The bisamides are prepared by the well-known procedures such as heating a mixture of the polyamine and the carboxylic acid or by the reaction of the acyl halide such as acyl chloride with the polyamine in the presence of a hydrogen halide acceptor such as triethylamine or pyridine.

Illustrative of the amidation reaction, the preferred bisamide, methyliminobis(propyloleamide), can be prepared as follows: 290 g. of methyliminobis(propylamine), H NCI-I CH CH N(CH CH CH CH NH l 130 g. of oleic acid and 1,360 g. of xylene are heated at reflux in a reaction vessel equipped with a modified Dean-Stark separator such that the xylene layer is continuously returned to the reaction vessel while the water is periodically removed. The refluxing and the removal of the water is continued until about 71 g. of water is removed, which process generally requires about 24 hours. The product is obtained as a 50 percent solution of methyliminobis(propyloleamide) (MIBPO) in xylene having Total Acid Number Equivalent (TANE) of less than about 3.3 mg. KOH/g. sample. It is to be noted that since the nonterminal nitrogen is a tertiary nitrogen, at tetrahydropyrimidine-type compound is not formed.

The gasolines into which the bisamides are incorporated to provide improved gasoline compositions comprise a mixture of hydrocarbons boiling in the gasoline boiling range. The gasoline may consist of straight chain or branched chain paraffins, cycloparaffins, olefins, and aromatic compounds or any mixture of these, such hydrocarbons being obtainable from straight run naphtha, polymer gasoline, natural gasoline, thermally or catalytically cracked hydrocarbons and catalytically reformed stocks. The gasoline can also contain any of the conventional additives normally used in gasolines such as alkyllead antiknock compounds, halogencontaining lead scavenging compounds, corrosion inhibitors, dyes, antioxidants, anti-rust agents, anti-icing agents, gum-inhibitors, anti-preignition agents and the like.

Utility The gasoline compositions of the invention have been found to minimize the formation of deposits in the carburetor and to remove the previously-formed deposits. The detergency of gasoline containing the additives was demonstrated by the clean-up of carburetors in (l) laboratory scale tests wherein the carburetors were purposely dirtied by a short term engine operation using increased ring gap in the piston rings, and by supplying the cngine blowby and a portion of the exhaust to the inlet air and (2) in a programmed chassis dynamometer (PCD) test wherein carburetors dirtied in service were used under simulated driving conditions with the vehicles operated for 6,500 miles under controlled conditions of idle, acceleration and deceleration. These tests show that when at least about 0.003 percent by weight of the bisamide is present in the gasoline, the carburetors are effectively cleaned and maintained in the clean condition.

The novel gasoline compositions have anti-icing properties and good water interaction properties. It is recognized that gasolines will unavoidably come into I contact with water since water is almost always present during handling, storage, and transportation of gasolines. The interaction of gasolines with water to form emulsions or to increase entrainment of water in gasoline is undesirable. The bisamide additive compounds when incorporated into gasolines in the concentration ranges contemplated for gasoline detergency and antiicing properties, do not adversely affect the water'interaction properties of the gasolines.

This absence of water interaction is surprising since another bisamide, iminobis(propyloleamide),

(not of the invention), which differs from methyliminobis-(propyldioleamide),

of the invention, only in having a nonterminal nitrogen which is a secondary amino instead of a tertiary amino group, has very high and unacceptable water interaction properties when incorporated into gasoline.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Example 1 This Example illustrates the carburetor detergency of the gasoline compositions containing a bisamide described herein in a laboratory scale test. In this test, the deposits are initially accumulated in the carburetor under specified conditions. The effectiveness of an additive as a carburetor detergent is then determined by operating the engine with a fuel containing the additive and then determining the amount of accumulated deposits which is removed. The fuel used in the test was base fuel known in the industry under the designation of MS-08.

A Chevrolet 6 cylinder, 230 cu. in. engine was used having a Carter No. 3511-5 carburetor and an ice tower with heater. The ring gap of the top piston ring was increased by one-eighth inch to a gap of 0.138 inch and installed in place of the second compression ring leaving the top ring groove empty thus increasing the blowby. The total engine blowby was directed to the carburetor air cleaner from the dome cover. The air cleaner filter element was eliminated. The exhaust line was modified to supply engine exhaust to the carburetor air cleaner. The distributor vacuum advance was eliminated to maintain spark advance of 4 before top center.

The operating conditions were as follows: engine speed at 700 i rpm; water outlet temperature 175 i: 2.5F., air/fuel mixture set for maximum vacuum; carburetor air cooled by passage through the ice tower and then reheated to 9095F.; engine exhaust supply to the carburetor air inlet controlled as indicated below. For the deposit accumulation, new spark plugs were installed, the motor oil was changed to an SAE 30 low detergent oil, and the carburetor, air cleaner housing and the exhaust system were cleaned. The engine was started with the exhaust feed valve to engine inlet air closed. The speed was adjusted to 700 rpm at maximum vacuum. The exhaust feed valve was opened and the engine speed maintained at 700 rpm. The exhaust feed valve opening is such that while the engine still operates smoothly without stalling the maximum amount of exhaust is fed to the engine. The engine was operated for 10 hours or until it could no longer be kept running under these conditions. The carburetor was removed and rated using a visual rating chart on which a rating of 100 is clean. If a rating cleaner than 30 was obtained, additional deposit accumulation operation was carried out.

To determine the detergency effectiveness of an additive, the engine was operated with the gasoline containing the additive under the same operating conditions except that the blowby and exhaust were not fed into the air inlet. The detergency test was carried out for 50 hours and the percent clean-up was determined as follows:

1. 100 minus the rating of deposit accumulation amount available for clean-up;

2. rating after clean-up minus rating of accumulation amount of clean-up;

3. percent clean-up amount of clean-up divided by amount available for clean-up times 100.

The results of the carburetor detergency tests are summarized in Table l. The bisamide used, methyliminobis-(propyloleamide), MIBPO, was added to the gasoline as a 50 percent by weight solution in Xylene and was present at a concentration of 0.003 weight percent of the gasoline. In tests 1 to 6, the gasoline additionally contained 0.5 weight percent of 2- ethylhexanol.

TABLE I Carburetor Detergency 71 Carburetor Test No. Clean-Up ooqchua-butu- EXAMPLE 2 The effectiveness of the gasoline composition in reducing the deposits already present in the carburetor was demonstrated in a Programmed Chassis Dynamometer (PCD) Test. In the deposit accumulation step of Example 1, the deposits were formed under controlled laboratory conditions using a single type of fuel and for a relatively short period of time whereas under actual service conditions, different types of fuels are used and the driving conditions are extremely varied. It is therefore possible that the type of deposit formed in the carburetor in actual use might differ from that accumulated under controlled laboratory conditions; such deposits for example may differ in their response to detergent-containing gasoline.

For the PCD test, field-dirtied carburetors were ob tained from carburetor rebuilders. No prior histories for these carburetors were available. Since the dirty carburetors varied in deposit formation, particularly in the presence or absence of deposits held loosely, the dirty carburetors were standardized by using the carburetors as received for 1,500 miles of the driving schedule described below. The fuel used throughout was MS-O8 base fuel. The PCD test utilizes a driving schedule of a vehicle on a chassis dynamometer, which driving schedule simulates typical driving sequences of idle acceleration, and deceleration usually encountered in normal driving.

The driving schedule used was the Durability Driving Schedule (Federal Register Volume 35, Number 219, November 10, l970, Part II, Appendix D). The schedule consists of ll laps of a 3.7 mile course. The basic vehicle speeds for each of the first nine laps are from 30 mph to 45 mph, for the tenth lap 55 mph, and for the eleventh lap mph. During each of the first-nine laps there are four stops with 15 seconds of idle. Normal acceleration and deceleration. are used. In addition, there are five light decelerations each lap from the base speed to 20 mph followed by light acceleration to the base speed. The tenth lap is run at a constant speed of 55 mph. The eleventh lap is started with a wide open throttle acceleration from stop to 70 mph. A normal deceleration to idle followed by a. second wide open throttle acceleration occurs at the midpoint of the lap. The above 1 1 laps were repeated for the mileage accumulation of 3,000 miles, 5,000 miles and 6,500 miles, at which mileages the carburetors were examined and rated for deposits as in Example 1. The results are summarized in Table ll.

For comparison purposes, two of the gasoline detergent compositions presently used commercially were also tested in the PCD test. Commercial additive A was an amine phosphate type composition while commercial additive B was a composition containing polybuteneamine, n-butanol, top cylinder oil and xylene. The bisamide additive was methyliminobis(- propyloleamide) which was added to the gasoline as a 50 percent by weight solution in xylene, thus the concentrations used of 20 lbs/1,000 barrels and 40 lbs./ 1,000 barrels correspond to 0.004 percent and 0.008 percent by weight of the bisamide.

TABLE u TABLE Ill-Continued Carburetor Detcrgency Programmed Chassis Dynamometer (PCD) Tests Concentration 7r Carburetor Clean Up The above results show that the compositions of this invention are effective detergents in cleaning carburetors which contained deposits formed in actual use.

EXAMPLE 3 This Example illustrates the anti-icing properties of the gasoline composition of the invention. The antiicing properties are determined by Engine Carburetor Anti-icing Test described below. The test is carried out by using a Chevolet 230 cu. in 6 cylinder engine. The environment of the carburetor is mantained at 40F. and 95 percent relative humidity. Cool, essentially water-saturated air is thus drawn through the carburetor. The test consists of running the engine on a two-part cycle: (1) 20 seconds with open throttle at 1,600 rpm. and (2) l seconds with the throttle almost closed at 400 rpm. 1

During the test, ice forms on the throttle plate and causes the engine to stall by blocking the flow of air when the throttle plate is almost closed during the idle portion (400 rpm) of the test. Normally, in the absence of an effective additive, engine stalling occurs after about 3 to 5 cycles. Generally an additive is considered effective if it prevents stalling to about cycles; however it is highly desirable that an anti-icing agent prevent stalling to about 25 cycles or more. The results are summarized in Table 111. Methyliminobis(propyloleamide) was added to the gasoline as'a 50 percent by weight solution in xylene.

TABLE 111 Anti-Icing Tests Anti-Icing Tests Active ingredient wt.

No. of cycles to stall Test No. Additive 5 MlBPO The above results show that the novel gasoline compositions are excellent anti-icing agents with the methyliminobis(propyloleamide) present at a concentration of about 0.004 wt. percent. Since the bisamide is shown to have practically no anti-icing effect at the concentration of 0.002 wt. percent, it is clear that if anti-icing protection is desired, the bisamide should. be used at a concentration higher than 0.002 wt. percent, say about 0.003 wt. percent.

Tables I, I1, and Ill amply demonstrate the beneficial carburetor cleaning and anti-icing properties of the novel compositions when employed as fuel in a process for operating an internal combustion engine.

EXAMPLE 4 This example illustrates the good water interaction properties of the gasoline compositions described herein. The tests were carried out according to Method 3251.7 Federal Test Method Standard No. 7918 whereby the hydrocarbon fuel containing the additive is vigorously shaken with an aqueous phosphate buffer solution and the condition of the interface observed. Since the rating in the above method gives the designations for a narrow range of interface characteristics a new rating system was devised which provides for a greater degree of differentiation of the interface characteristics, particularly for interface conditions not provided for in the above method. The rating system used and the comparison with the rating in Method 3251.7 for the different interface characteristics are summarized in Table IV.

TABLE IV Water Interaction Ratings Method 325 l .7 Rating Rating 1 1 Clean, clear interface no bubbles 2 lb clear bubbles covering of the interface. No lace or scum.

Clear bubbles covering 50% of the interface. No lace or scum Loose lace or sum covering 507c of the interface. No bubbles. Thin line interface.

Loose lace or scum covering 50% of the interface. No bubbles. Thin line interface.

Tight lace or scum covering the entire interface. No bubbles. Thin line interface.

Layer of bubbles some scum or emulsion. Line interface disappearing. Thick scum with emulsion layer between fuel and water phases. Three distinct layers.

Water layer completely emulsified. Two layers.

l0 4 N interface. Total emulsion or miscibility.

Water interaction ratings of isooctane containing six different preparations of methyliminobis(propyloleamide) containing different amounts of residual acidity (TANE) are given below. In tests 1, 3, 4 and 5, the isooctane composition also contained 0.5 wt. percent of 2-ethylh'exanol. For comparative purposes, water interaction ratings of iminobis(propylolcamide), lBPO, as an additive are also included. The water interaction ratings are summarized in Table V. TANE values are Total Acid Number Equivalent mg. KOl-l/g. of sample.

TABLE V R is selected from the group consisting of hydrogen and alkyl groups of l to 4 carbon atoms,

R is an alkyl group of l to 4 carbon atoms,

n is 2 or 3 and .x is 1 to 3.

2. A composition according to claim 1 wherein n is Water Interaction Ratings Table V shows that the novel gasoline compositions exhibit satisfactory water interaction properties when the bisamide is used in the concentration ranges contemplated for carburetor detergency and anti-icing effects. Ratings in the presently used rating system of 4 or less are considered to be satisfactory. The above data also show that in order to obtain satisfactory water interaction rating, the bisamide should have a T ANE of less than about 4. The iminobis(propyloleamide) (IBPO) used in Test No. 7 shows very poor water inter action properties (rating of 9 at all concentrations).

The embodiments of the invention in which an exclusive property of privilege is claimed are defined as follows:

l. A gasoline composition having from about 0.003 to 0.02 weight percent of a bisamide compound of the formula wherein carbon atoms,

3 and x is l.

3. A composition according to claim 2, wherein the bisamide is methyliminobis(propyloleamide).

4. A composition according to claim 1 having from about 0.004 to 0.008 weight percent of the bisamide.

5.. A composition according to claim 2 having from about 0.004 to 0.008 weight percent of the bisamide. 6. A composition according to claim 3 having from about 0.004 to 0.008 weight percent of the bisamide. 7. A concentrate of about 10 to weight percent of a bisamide compound of the formula C HuN-AO wherein Ac is an aliphatic hydrocarbyl acyl group of 8 to 20 carbon atoms,

R is selected from the group consisting of hydrogen and alkyl groups of l to 4 carbon atoms,

R is an alkyl group of l to 4 carbon atoms,

11 is 2 or 3 and x is l to 3 in a hydrocarbon solvent.

* =l l= l

Claims (7)

1. A GASOLINE COMPOSITION HAVING FROM ABOUT 0.003 TO 0.02 WEIGHT PERCENT OF BISAMIDE COMPOUND OF THE FORMULA

2. A composition according to claim 1 wherein n is 3 and x is 1.

3. A composition according to claim 2, wherein the bisamide is methyliminobis(propyloleamide).

4. A composition according to claim 1 having from about 0.004 to 0.008 weight percent of the bisamide.

5. A composition according to claim 2 having from about 0.004 to 0.008 weight percent of the bisamide.

6. A composition according to claim 3 having from about 0.004 to 0.008 weight percent of the bisamide.

7. A concentrate of about 10 to 70 weight percent of a bisamide compound of the formula