Title:
Gasoline
United States Patent 3894849


Abstract:
Composition exhibiting good anti-icing, anti-rust and carburetor and lower engine detergent properties and comprising a hydrocarbon mixture boiling in the gasoline range and an effective amount, usually 0.002-0.2% by weight, based on the weight of the hydrocarbon mixture, of a generally liquid, acylated polyalkylene polyamine which is substantially free of nitrogen-containing cyclic groups and is of the formula ##EQU1## wherein ##EQU2## R' is C9-21 saturated or unsaturated aliphatic hydrocarbyl, n is 2 or 3 and x is 2-6.



Inventors:
POLSS PERRY
Application Number:
05/419972
Publication Date:
07/15/1975
Filing Date:
11/29/1973
Assignee:
E. I. du Pont de Nemours & Co. (Wilmington, DE)
Primary Class:
Other Classes:
44/419, 252/392, 554/57
International Classes:
C10L1/14; C10L1/224; C10L1/18; C10L1/22; (IPC1-7): C10L1/22
Field of Search:
44/66,DIG.1 252
View Patent Images:
US Patent References:
3687644N/A1972-08-29Delafield et al.
3468639GASOLINES CONTAINING DEPOSIT-REDUCING MONOAMIDES OF POLYAMINES CHARACTERIZED BY IMPROVED WATER TOLERANCE1969-09-23Lindstrom
3429673CORROSION INHIBITING ADDITIVE COMPOSITIONS FOR FUEL OILS1969-02-25Reese et al.
32961332-stroke engine lubricants1967-01-03Ratner et al.
3169980Fatty acid polyamide1965-02-16Benoit
3166548Condensation products1965-01-19Kirkpatrick et al.
3035070Dialkylpolyaminopolyalkalene amides1962-05-15Carpenter et al.
2956020Anti-corrosion compositions1960-10-11Suprin et al.
2922708Gasoline compositions1960-01-26Lindstrom et al.
2902353Anti-stall gasoline1959-09-01Becker et al.
2862800Gasoline fuels1958-12-02Cantrell et al.
2807525Additive for motor fuels1957-09-24Foreman
2805135Stabilized hydrocarbon fuel oil compositions and stabilizaers therefor1957-09-03Bell et al.
2786745Fuel oil1957-03-26Stayner et al.
2647125Acylated imidazolines and method for preparing the same1953-07-28Gunderson
2622018Motor fuel1952-12-16White et al.



Primary Examiner:
Gantz, Delbert E.
Assistant Examiner:
Vaughn I.
Claims:
The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows

1. Composition exhibiting good antiicing, anti-rust and carburetor and lower engine detergent properties and comprising a hydrocarbon mixture boiling in the gasoline range and 0.002-0.02% by weight, based on the weight of the hydrocarbon mixture, of a generally liquid, acylated polyalkylene polyamine which is substantially free of nitrogen-containing cyclic groups and is of the formula ##EQU7## wherein R is selected from H and ##EQU8## at least two R groups ##EQU9## R' is C9-21 saturated or unsaturated aliphatic hydrocarbyl, n is 2 or 3 and x is 4 .

2. Additive for imparting good anti-icing, anti-rust and carburetor and lower engine detergent properties to a hydrocarbon mixture boiling in the gasoline range, said additive comprising a 30-70% by weight alkanol or aromatic hydrocarbon solution of a generally liquid, acylated polyalkylene polyamine which is substantially free of nitrogen-containing cyclic groups and is of the formula ##EQU10## wherein R is selected from H and ##EQU11## at least two R groups ##EQU12## R' is C9-21 saturated or unsaturated aliphatic hydrocarbyl, n is 2 or 3 and x is 4 .

3. The additive of claim 2 which contains an anti-icing agent which is an amine carboxylate salt of the formula ##EQU13## R1 is C8-24 saturated or unsaturated aliphatic hydrocarbyl, each of R2 and R3 is selected from H and CH3, R4 is C11-21 saturated or unsaturated aliphatic hydrocarbyl, each of a and b is 1-14 and the sum of a and b is 2-15 (a and b being average values), said salt having at least two (CH2 CH2 O) groups and the weight ratio of the polyamine to the salt being in the range of 1:10 to 10:1.

4. The additive of claim 3 wherein the weight ratio of polyamine to anti-icing agent is in the range 1:1.5 to 1.5:1.

5. The additive of claim 4 wherein the anti-icing agent is a salt of tall oil fatty acid and a C18 n-alkyl or n-alkenyl amine containing 4-6 oxyethylene groups.

6. The additive of claim 2 wherein n is 2.

7. The additive of claim 6 wherein R'-C represents the acyl moiety of tall oil fatty acid.

8. The composition of claim 1 wherein n is 2.

9. The additive of claim 7 wherein the total number of ##EQU14## groups in the formula is three.

Description:
BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to improved gasolines having good anti-icing, anti-rust and carburetor and lower engine detergent properties.

2. Description of the Prior Art

Rough idling and engine stalling of carburetted, automotive, spark ignition engines have long been recognized as problems associated with the operation of automotive vehicles. One of the causes of rough idling and stalling is the accumulation of deposits on the carburetor throttle plate and on the surrounding wall. The accumulation of deposits interferes with the normal air flow in the carburetor, leading to fuel-rich mixtures. The deposits may be produced, for example, by the accumulation of contaminants in the air, engine blowby and dust. Corrective measures include periodic carburetor cleaning, which is costly, or increasing the normal engine idling speed, which results in greater difficulty in handling the vehicle and in waste of the fuel.

The engines in the automotove vehicles presently being produced may provide additional problems, particularly during the engine warm-up periods, which problems may be manifested as frequent engine stalling, rough idling and hesitation. Such problems are generally recognized as consequences of the various engine modifications and the added devices designed to control exhaust emissions of hydrocarbons, carbon monoxide and oxides of nitrogen. These difficulties may be compounded by the aforesaid operational difficulties brought about by the accumulation of deposits in the carburetor.

It is known that deposits present in the carburetor may be decreased or the accumulation of such deposits inhibited by utilizing fuels which contain certain additives which are known as carburetor detergents. Although it is recognized that the activity of such additives need not involve a detergency mechanism, the fact is that many such additives are effective in cleaning a carburetor which already has accumulated deposits and in maintaining the cleanliness of a clean carburetor. Many types of compounds have been suggested in the art as carburetor detergents. These include long chain amines, amine phosphates, amides, aminoamides and amine carboxylates. The most effective types of compounds are the amine phosphates, used alone or in combination with other additives. However, it is being increasingly recognized that the presence of phosphorus compounds in fuels is undesirable because of the possible deleterious effects of phosphorus on the exhaust gas emission control devices which are being installed on the engines of the automotove vehicles currently being produced. Hence, a need exists for an efficient non-phosphorus-type carburetor detergent additive for motor fuels.

In addition to carburetor detergency additives modern motor fuels require other additives to improve fuel performance, for example, those which provide anti-rust protection, anti-icing protection and control of intake system deposits. For simplified handling and economy the desirable performance characteristics should be obtained with a minimum number of additives and the additives should be effective at low concentrations. Preferably, the additive should provide several performance characteristics, that is, it should be a multifunctional additive. Although numerous multifunctional additives are suggested in the art, many are not acceptable, either because they introduce some undesirable side effects or because they must be used in excessive amounts to provide the desirable properties.

SUMMARY OF THE INVENTION

It is an object of this invention to provide a phosphorus-free additive for motor fuels. It is a further object to provide such an additive which exhibits multi-functional performance characteristics, including anti-rust, anti-icing and carburetor and lower engine detergency. A still further object is to provide a motor fuel composition having multifunctional performance characteristics.

In summary, this invention resides in a composition exhibiting good anti-icing, anti-rust and carburetor and lower engine detergent properties and comprising a hydrocarbon mixture boiling in the gasoline range and an effective amount, usually 0.002-0.02% by weight, based on the weight of the hydrocarbon mixture, of a generally liquid, acylated polyalkylene polyamine which is substantially free of nitrogen-containing cyclic groups and is of the formula ##EQU3## wherein R is H and/or ##EQU4## R' is C9-21 saturated or unsaturated aliphatic hydrocarbyl, n is 2 or 3 and x is 2-6.

DETAILED DISCUSSION OF THE INVENTION

The acylated alkylene polyamines which are used in this invention as summarized above may be fully acylated, that is, each nitrogen atom of the polyamine may have an acyl substituent, or the polyamine may be partially acylated, that is, just some of the nitrogen atoms of the polyamine may have acyl substituents. Generally, when two or more acyl groups are present, it is believed that the terminal nitrogen atoms of the polyamine molecule containg acyl substituents. Alkylene polyamines which are useful for the preparation of the acylated polyamines are represented by the formula H2 N--(Cn H2n NH)x H wherein n and x are as defined above. It is to be understood that when n is three, Cn H2n can be either a 1,2- or 1,3-propylene group. The alkylene polyamines and their preparations are well known in the art. For example, a desired alkylene polyamine can be prepared by reacting an appropriate alkylene dihalide and ammonia. Representative of known amines are diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, dipropylenetriamine, tripropylenetetramine, tetrapropylenepentamine and pentapropylenehexamine, all of which are commercially available. Mixtures of alkylene polyamines can also be used to prepare the acylated polyamine. Polyethylene polyamines are particularly preferred because of their greater availability.

The alkylene polyamines can be acylated by reacting the polyamine with a carboxylic acid (preferred because of generally lower cost and ready availability) of the formula R'COOH wherein R' is as defined above, or an anhydride or an acid halide of such a carboxylic acid by procedures well known in the art. Although the immediately following disclosure is provided in terms of a carboxylic acid being used, it is to be understood that a similar disclosure could be formulated for an anhydride or an acid halide.

The carboxylic acid used to acylate the polyamine is an aliphatic hydrocarbon monocarboxylic acid of 10-22 carbon atoms; it can be saturated or unsaturated. Included are alkanoic, alkenoic and alkadienoic acids. Carboxylic acids wherein the hydrocarbyl portion of the molecule is of a straight chain configuration are preferred since, generally, less severe reaction conditions are required for acylation with such acids. Representative carboxylic acids include decanoic, decenoic, dodecanoic, dodecenoic, tridecanoic, tridecenoic, tetradecanoic, tetradecenoic, hexadecanoic, hexadecenoic, octadecanoic, octadecenoic, octadecadienoic, eicosanoic, uneicosanoic and doeicosanoic acids. Mixed acids can be employed, the mixture being preferred because of generally lower cost and better properties of fluidity and greater solubility. Acid mixtures such as those obtained by hydrolysis of natural fats and oils are useful. Included are those derived from coconut oil, corn oil, cottonseed oil, tallow and soybean oil. The acids prepared from tallow are ordinarily mixtures of tetradecanoic, tetradecenoic, hexadecanoic, hexadecenoic, octadecanoic, octadecenoic, octadecadienoic and eicosanoic acids; those prepared from soybean oil are mixtures containing hexadecanoic, octadecanoic, octadecadienoic and eicosanoic acids; those prepared from cotton seed oil are mixtures ordinarily containing tetradecanoic, hexadecanoic, octadecanoic, octadecadienoic and eicosanoic acids; and those prepared from coconut oil contain decanoic, dodecanoic, tetradecanoic, hexadecanoic, octadecanoic, octadecenoic and octadecatrienoic acids with a very small amount of octanoic acid. A particularly useful and preferred acid mixture is tall oil fatty acid obtained from tall oil. Tall oil is a mixture of rosin and fatty acids released by acidulation of the black liquor soap skimmed off the black liquor from the sulfate process in the manufacture of Kraft paper. Crude tall oil is commonly fractionally distilled to provide various cuts wherein the ratio of fatty acids to rosin acids varies from 1:99 to 99:1. In the context of this description tall oil fatty acid is intended to include tall oil compositions having a fatty acid content of at least about 50% by weight, the balance being mainly rosin acids in admixture with minor amounts of unsaponifiable materials of unknown chemical composition. The fatty acids in tall oil fatty acids consist mainly of oleic, linoleic, conjugated linoleic, palmitic, stearic, palmitoleic, arachidic and behenic acids. Tall oil fatty acids which are commercially available include those with the following compositions: palmitic (0.1-5.3%); palmitoleic (0.1-2.1%); stearic (2.1-2.6%); oleic (39.3-49.5%); linoleic (38.1-41.4%); eicosanoic (1.2-1.9%); eicosadienoic (0.5-3.2%); eicosatrienoic (0.4-2.9%); and behenic (0.4-0.9%) acids, with the balance being rosin acids, unidentified acids and unsaponifiable materials.

As already indicated the acylated polyamines can be prepared by methods well known in the art. Thus, when an anhydride is used as the acylating reactant, the anhydride is mixed with the amine and the mixture is heated slightly. If preferred a catalyst, such as pyridine, can be used. When an acid halide is the acylating reactant, the acylation can be carried out in the presence of aqueous alkali according to the well known Scotten-Baumann reaction. With a carboxylic acid as the acylating reactant the preferred method is to react the carboxylic acid and the polyamine at 70°-200°C. in the absence of any solvent, and to remove no more than about one mole of condensation water for each mole of the acid reacted. The ratio of the carboxylic acid to the polyamine used in the reaction depends upon the particular polyamine used and the particular product desired. It can vary from one mole of the carboxylic acid per mole of the polyamine to one mole of the acid per gram atom of nitrogen per mole of the polyamine. The preferred acylated polyamine is prepared from tall oil fatty acid and tetraethylenepentamine reacted in the molar ratio of 3:1.

It is well known in the art that, under certain reaction conditions, when a carboxylic acid is reacted with an alkylene polyamine, particularly an ethylene polyamine or a propylene polyamine, a cyclization reaction involving the primary amino group, its adjacent amino group and the carboxylic acid takes place to form nitrogen-containing cyclic compounds which are imidazoline derivatives (when an ethylene polyamine is used) or tetrahydropyrimidine derivatives (when a propylene polyamine is used). The acylated polyamine compounds employed herein are substantially free of such nitrogen-containing cyclic groups. By substantially free of nitrogencontaining cyclic groups is meant that the acylated polyamine contains less than about 5% by weight of the imidazoline or tetrahydropyrimidine compounds. Generally, when the acylated polyamine is prepared by reacting an anhydride or an acid halide, and particularly when such reaction is carried out at a reasonably low temperature, for example, below about 150°C., no nitrogen-containing cyclic compound is formed. In the reaction of a carboxylic acid and a polyamine it has been discovered that the formation of nitrogen-containing cyclic compounds are avoided when the reaction is carried out in the absence of any solvent, the reaction temperature is kept below about 200°C. and removal of water of condensation is restricted to a maximum of one mole of water per mole of caraboxylic acid reacted. The nitrogen-containing cyclic compounds differ in performance properties from the acylated polyamines even though both compositions are prepared by reacting, in the same reactant ratio, the same carboxylic acid and alkylene polyamine, the former being prepared in a solvent, the latter being prepared in the absence of a solvent. As demonstrated hereinafter, the latter compound is effective as an engine detergent (keeping sludge down and piston skirts clean) and is responsive to a dehaze agent whereas the former compound (for example, an imidazoline) is not effective as an engine detergent and is not responsive to a dehaze agent.

The above-described acylated polyamines are useful as an additive for hydrocarbon fuels, particularly motor fuels boiling in the gasoline range, and confer the multi-functional properties of carburetor and lower engine detergency, anti-rust protection and some anti-icing protection. Their utility and suitability as a multifunctional gasoline additive are enhanced by the ancillary properties of good resistance to water extraction and emulsion formation and good response to a dehaze agent. Generally, to obtain the benefit of its multifunctional properties, the acylated polyamine is incorporated into gasoline at a concentration of 0.002-0.02% by weight, preferably 0.003-0.01%, most preferably 0.004-0.008%. Incorporation of more than about 0.02% is wasteful of the additive since no additional benefits are derived from the added quantity.

Since the acylated polyamines are generally liquids, they are well-suited for facile addition to motor fuels at the refinery. Such incorporation may be made by any method known in the industry for the addition of a liquid composition to motor fuels. Preferably, the acylated polyamine is provided as a solution in a suitable solvent, such as methanol, ethanol, propanol, butanol, benzene, toluene and xylene, or a mixture of any two or more of these solvents. The solution can contain 10-90% by weight of the acylated polyamine, preferably 30-70%. To such a solution, which is considered to be an additive concentrate, can be added a dehaze agent, which enhances the fuel-water separation characteristics of a fuel, an an anti-icing agent, the latter providing increased carburetor anti-icing protection. Typically, a concentrate can contain, based upon the weight of acylated polyamine, 10-25% of a dehaze agent and/or 0-150% of an anti-icing agent. Dehaze agents are readily available commercially, such products generally being highly polar compounds such as oxyalkylenated alkyl phenols with or without carboxyl groups. Although anti-icing agents also are readily available, preferred is one of the formula RO[CH(CH 3)--CH2 O]m --[CH2 CH2 O]n H wherein R is an alkyl group of 12-22 carbon atoms, m and n are integers, the sum of which is 7-30, n is O- 4 and m/n is at least 2. The most preferred anti-icing agent employed herein is an amine carboxylate salt of the formula ##EQU5## R1 is C8-24 saturated or unsaturated aliphatic hydrocarbyl, each of R2 and R3 is selected from H and CH3, R4 is C11-21 saturated or unsaturated aliphatic hydrocarbyl, each of a and b is 1- 14 and the sum of a and b is 2-15 (a and b being average values), said salt having at least two (CH2 CH2 O) groups. Such an amine carboxylate salt can be readily prepared by a neutralization reaction involving an appropriate amine which contains the oxyalkylene groups and an appropriate hydrocarbon monocarboxylic acid. Since such amine carboxylate salts, in addition to having anti-icing properties, also provide corrosion protection and carburetor detergency, when they are used in combination with the acylated polyamine, less of the latter is required. It has been discovered that such a combination provides performance characteristics, at relatively low concentrations in gasolines, which are more representative of the performance of each of the components used separately at higher concentration levels. Thus, a combination consisting of approximately equal weights of acylated polyamine and amine carboxylate salt provides substantially the same carburetor anti-icing protection at about one half of the normally required amount of the amine carboxylate salt alone and it provides substantially the same carburetor detergency at about one half of the normally required amount of the acylated polyamine alone.

Combinations of an acylated polyamine and an amine carboxylate salt in weight ratios of about 1:10 to 10:1 are useful; the preferred ratios are in the range 1:1.5 to 1.5:1. When the combination is used in motor fuels, the concentration of the acylated polyamine should be at least about 0.002% by weight. The preferred acylated polyamine in the combination is that prepared from tall oil fatty acid and tetraethylenepentamine by reacting the two materials at a molar ratio of 3:1. The preferred amine carboxylate salt in the combination is that prepared from tall oil fatty acid and a C18 n-alkyl or n-alkenyl amine containing about 4-6 oxyethylene groups.

The motor fuel to which the acylated polyamine is added to impart the desired characteristics described above comprises a mixture of hydrocarbons boiling in the gasoline range. The base fuel can consist of straight chain or branched chain paraffins, cycloparaffins, olefins and aromatic compounds or any mixture of such hydrocarbons obtainable from straight run naphtha, polymer gasoline, natural gasoline, thermally or catalytically cracked hydrocarbon stocks and catalytically reformed stocks. The gasoline can also contain varying amounts of conventional fuel additives, such as anti-knock compounds, including tetramethyllead, tetraethyllead and mixed alkyllead, scavenging agents, dyes, anti-oxidants, anti-icing agents, rust inhibitors, detergents and anti-preignition agents.

The following experiment illustrates the preparation of acylated polyalkylene polyamines.

Experiment

a. Tetraethylenepentamine (189 g., 1 mole) was placed in a reaction flask equipped with a condenser, thermometer, agitator and an addition funnel. Agitation was started and tall oil fatty acid was added through the addition funnel. The tall oil fatty acid had the following composition: 2.3% palmitic, 0.6% palmitoleic, 2.3% stearic, 41.0% oleic, 32.8% linoleic (cis-9, cis-12), 3.8% linoleic (cis-9, trans-11), 1.9% eicosanoic, 4.8% linoleic (trans-9, trans-11), 2.1% eicosadienoic, 2.9% eicosatrienoic and 0.9% behenic acids, the balance unknown. Although the addition of the acid was accompanied by evolution of heat, additional heat was supplied to the reaction mixture to maintain good fluidity in the temperature range 65°-95°C. The total amount of the tall oil fatty acid added (852 g.) was equivalent to three moles of carboxylic acid functionality. After the addition of the tall oil fatty acid was completed, a vacuum of 100 mm. of Hg was applied to the reaction system and the reaction mixture was heated to 175°C. The water evolved upon heating was condensed and collected. The heating was terminated when 52.9 gm. of water (98% of theory of 1 mole of water per mole of acid reacted) were collected. The acylated tetraethylenepentamine obtained was a clear amber liquid containing 6.5% nitrogen and having an acid number of 15. Infrared analysis of the product indicated the presence of amide groups and the absence of imidazoline groups.

b. Using the general procedure described in Part (a) the acylated polyamines shown in Table 1 were prepared from tall oil fatty acid. The reaction temperatures employed were in the range 125°-190°C. and the vacuum used was in the range 35-100 mm. of Hg. In all cases the reaction was terminated when about one mole of water per mole of acid reacted was collected. All condensation reactions were carried out in the absence of solvent. Infrared analyses of the products showed the presence of amide groups and the substantial absence of imidazoline groups.

TABLE 1 ______________________________________ Moles of Tall Oil Acid Run Polyamine Per Mole of Polyamine ______________________________________ 1 Diethylenetriamine 2 2 Diethylenetriamine 3 3 Triethylenetetramine 2 4 Tetraethylenepentamine 1 5 Tetraethylenepentamine 2 ______________________________________

The following examples demonstrate the usefulness of the acylated polyalkylene polyamines as multifunctional gasoline additives.

EXAMPLE 1

The anti-rust properties of the acylated polyalkylene polyamines are determined according to the method of ASTM D-665, Procedure A. In this test 300 ml. of the hydrocarbon fuel containing the addition test is stirred with 30 ml. of distilled water at a temperature of 32°C. (90°F.) with a cylindrical steel specimen completely immersed therein. The test is carried out for 20 hours. With the base fuel alone the steel specimen usually has about 80% of the surface covered with rust spots after 20 hours. The results obtained with the acylated polyamines prepared in the above experiment are tabulated below.

TABLE 2 ______________________________________ Compound of Experiment % Rust ______________________________________ a 0 b-1 0 b-2 0 b-3 0 b-4 0 b-5 0 ______________________________________

EXAMPLE 2

The usefulness of the acylated polyalkylene polyamines as a carburetor detergent is demonstrated by two series of tests. The first test measures the effectiveness of the polyamines in removing deposits already present in the carburetor. The second test measures the effectiveness of the polyamines in keeping the carburetor clean.

A. In the first test deposits are initially accumulated in the carburetor under specified conditions. The effectiveness of an additive as carburetor detergent is then determined by operating the engine with fuel containing the additive and measuring the amount of accumulated deposit removed. Chevrolet, 6 cylinder, 230 cubic inch engines having Carter No. 3511-S carburetors and ice towers with heaters were used. One engine was used to produce, in the shortest time, sufficient throttle body deposit for the cleanup phase of the test. Since the deposit accumulation phase of the test is carried out over a period of about 10 hours and the clean-up phase of the test requires about 50 hours, by utilizing one engine for deposit accumulation and several engines for the clean-up portion of the test, the testing can be accomplished in a relatively short time. In the deposit accumulation engine the ring gap of the top piston ring was increased by 0.125 inch (0.32 cm.) to 0.138 inch (0.35 cm.) and the ring was installed in place of the second compression ring, leaving the top ring groove empty and thus increasing the blowby. The total blowby was directed to the carburetor air cleaner from the dome cover. The air cleaner element was eliminated. The exhaust line was modified to supply engine exhaust to the carburetor air cleaner. The engine was operated under the following conditions: the distributor vacuum advance was eliminated to maintain spark advance of 4° before top center; engine speed at 700 ± 10 r.p.m.; water outlet temperature 175 ± 2.5°F. (79 ± 1.5°C.); air/fuel mixture at maximum vacuum; carburetor air cooled by passage through an ice tower and then reheated to 90°-95°F. (32°-35°C); and engine exhaust supplied to carburetor air inlet as described below. The fuel used was MS-08, an industry standard fuel used for Sequence MS oil testing.

The engine was started with the exhaust feed valve to engine inlet air closed. The speed was adjusted to 700 r.p.m. at maximum vacuum. The exhaust feed valve was opened and the engine speed was maintained at 700 r.p.m. (the exhaust feed valve setting is critical). The setting was such as to feed the maximum amount of exhaust that the engine would accept and still operate smoothly without stalling. The engine was operated for about 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. A rating of 100 is considered as clean. If a rating cleaner than 30 is obtained, additional deposit accumulation is required.

For the clean-up phase of the test, the dirty carburetor was installed in another engine and the operating conditions described above were used except that normal piston rings wee used and the blowby and exhaust were not fed into the air inlet. Before the test new spark plugs were installed, SAE 30 low detergent oil was placed in the crankcase and the air cleaner housing and exhaust system were cleaned. The clean-up procedure was carried out for 50 hours in five 10-hr. segments, the ratings being made at appropriate intervals to determine the amount and speed of clean-up. The percent clean-up was determined according to the following formula ##EQU6## wherein RD is the carburetor rating after deposit accumulation and R0 is the carburetor rating after clean-up. The results are tabulated in Table 3.

TABLE 3 ______________________________________ % Clean-up Control Fuel 15 Control Fuel + 0.004% of Experiment (a) polyamine 35 ______________________________________

The above results show that the acylated polyamine is highly effective in removing deposits already present in the carburetor.

B. In the second test the carburetor keep-clean test (Onan) is carried out in a single cylinder engine to which a controlled amount of exhaust gas from another engine is mixed with air supplied to the test carburetor. The test carburetor throat consists of a two piece stainless steel liner fitted around the throttle plate shaft. The liner is easily removed for inspection and rating. The engine is operated under cycling conditions of one minute idling and three minutes of part throttle until an overall test period of two hours is achieved. The liner is visually rated on a scale of 0-10, the visual rating of 10 being given for a clean carburetor, 0 for a very dirty carburetor. The results are tabulated in Table 4.

TABLE 4 ______________________________________ Additive (0.004%) Onan Rating ______________________________________ None (Control Fuel) 4.5 Experiment (a) polyamine 8.5 Experiment (b-1) polyamine 7.4 Experiment (b-2) polyamine 7.6 Experiment (b-3) polyamine 6.2 Experiment (b-4) polyamine 7.4 Experiment (b-5) polyamine 5.8 ______________________________________

The above results show that the acylated polyamines are effective in keeping carburetors clean. Generally, a rating of at least 7 is desired for very effective carburetor detergency; thus, it is evident that the acylated polyamines of Experiments (b-3) and (b-5) should be used at concentrations greater than 0.004%.

EXAMPLE 3

The usefulness of the acylated polyalkylene polyamines as anti-icing additives for gasolines is demonstrated by two series of tests. The first test measures the effectiveness of the polyamines in reducing the tendency of fuels containing water to freeze in cold weather. The second test measures the effectivness of the polyamines in preventing ice formation on the throttle plate and the surrounding wall of the carburetor.

A. In the first test gasoline presaturated with water at room temperature is treated with the additive, placed in a fuel reservoir and circulated through a closed system containing a cooling coil and a filter cell. Pressure drop across a stainless steel screen (325 mesh, U.S. Sieve Series) due to ice accumulation and the time required to reach an indicated pressure drop are used as performance measures of fuels or fuel/additive combinations. The results obtained with the acylated polyamine of Experiment (a) are tabulated in Table 5. The test was run for 60 minutes or until a pressure drop of 140 inches of water was obtained.

TABLE 5 ______________________________________ Fuel Line Pressure Drop at 0°F. (-18°C.) ΔP (inches of H2 O) Time (min.) ______________________________________ Control Fuel 140 15 Control Fuel + 0.004% Experiment (a) polyamine 38 60 ΔP = pressure drop ______________________________________

B. In the second tests the carburetor anti-icing properties of the polyamines are determined by using a gasoline containing an additive and measuring the number of cycles before stalling. The test is carried out with a Chevrolet, 230 cubic inch, 6 cylinder engine. The environment of the carburetor is maintained at 40°F. (4°C.) and 95% relative humidity. At these conditions essentially water saturated cool air is drawn through the carburetor. The test consists of running the engine on a two part cycle, namely, 20 seconds with open throttle at an engine speed to 1,600 r.p.m. and 10 seconds with the throttle almost closed at 400 r.p.m. (idling speed). During the test, with a poor anti-icing gasoline, ice forms on the throttle plate and on the surrounding carburetor walls and causes the engine to stall by blocking the flow of air when the throttle plate is almost closed during the idling portion of the cycle. With a poor anti-icing gasoline engine stalling occurs in about 3-5 cycles. The number of cycles to stall is an average of two or more tests. Generally an additive is considered effective if it prevents stalling to about 10 cycles; an excellent anti-icing additive prevents stalling to at least about 25 cycles.

The compound of Experiment (a) was evaluated as a carburetor anti-icing additive at the 0.004% by weight level in two series of gasolines. In an unleaded gasoline having a 93.3 research octane number, a Reid vapor pressure of 9 lbs., a 50% distillation point of 218°F. (103.4°C.) and containing (by volume) 58% saturates, 2% olefins and 40% aromatics, stalling occurred after 6.1 cycles (average). This fuel with 0.004% by weight of the polyamine of Experiment (a) did not stall in 25 cycles. In a leaded fuel having a 94-96 research octane number, a Reid vapor pressure of 9.5 lbs., a 50% distillation point of 202°F. (94.4°C.) and containing (by volume) 55-75% saturates, 15-20% olefins and 20-25% aromatics, stalling occurred after 4.5 cycles (average). This fuel with 0.004% by weight of the polyamine of Experiment (a) stalled after 7.1 cycles (average). Thus, the polyamine shows excellent anti-icing performance in the higher midpoint gasoline and shows some effect in the lower midpoint fuel. It has been found that this polyamine shows improved icing control in a poorly responsive fuel when it is used in combination with another anti-icing compound, for example, an alkyl polyoxyalkylene ether, and particularly C12-16 H25-33 O[CH(CH3)CH2 O]7 H (designated A in Table 6) wherein C12-16 H25-33 designates a mixture of alkyl groups of 12-16 carbon atoms. An anti-icing performance greater than the additive effects of each anti-icing compound alone is obtained. The results are summarized in Table 6.

TABLE 6 ______________________________________ No. of Cycles Additive Wt. % to Stall ______________________________________ None (Control Fuel) -- 4.9 Experiment (a) polyamine 0.004 6.5 A 0.006 14 Experiment (a) polyamine 0.004 + 25+ + A 0.006 (A) ______________________________________

The results show that the acylated polyamines provide excellent carburetor anti-icing performance in responsive fuels and in poorly responsive fuels are capable of providing excellent performance in combination with other antiicing compounds.

EXAMPLE 4

The usefulness of the acylated polyalkylene polyamines as a lower engine detergent is demonstrated by MS Sequence V-B Test. MS Sequence V-B Test is used in the industry primarily to evaluate motor oil performance in reducing engine deposits produced by low and medium temperature engine operating conditions. However, since it is known that gasoline qualities also influence results, the test is often used to evaluate gasoline performance in reducing engine deposits by maintaining lubricating oil quality constant. A Ford, 289 cubic inch displacement (C.I.D.) engine is used and the test consists of operating the engine for 192 hours in 48 four-hour cycles. Each four-hour cycle is composed of three different types of engine operation, namely, idle, low temperature operation and medium temperature operation. Every fourth cycle is folowed by an eighthour shutdown. The operating conditions are designed to promote sludge and varnish formation. The fuel used is MS-08 fuel, an industry standard for MS Sequence oil testing. The four-hour cycle is indicated in Table 7.

TABLE 7 __________________________________________________________________________ Stage 1 Stage 2 Stage 3 __________________________________________________________________________ Time, minutes 45 120 75 Speed, r.p.m. 500 2500 2500 Load, bhp None 86.6 86.6 Oil Temperature, °F. 120 175 205 Water Out Temperature, °F. 115 125 170 Air/Fuel Ratio 9.5 15.5 15.5 Intake Manifold Vacuum, inches of Hg 17-20 4.0-6.5 4.0-6.5 Spark Advance 6°BTDC 6 26 26 Blowby, cfm. -- -- 2.5-3.0 bhp = brake horsepower BTDC = before top dead center __________________________________________________________________________

At the conclusion of the test the engine is disassembled and inspected. A set of industry wide rating standard is used to derive numerical ratings. Overall sludge rating is obtained by inspecting rocker arm covers, bottom of intake manifold, oil screen, oil pan, valve deck area(including rocker arms), push rod chamber and timing gear cover. A rating from 0 to 10 (0 being very dirty and 10 being very clean) is assigned to each of the seven inspected areas. The summation of the ratings for the seven areas is multiplied by 5/7 to obtain an overall rating. Thus, the overall sludge rating can vary from 0 to 50 (50 being very clean). Similarly, an overall varnish rating is obtained by rating the following five areas on the scale of 0 to 10 by comparison with a standard varnish color scale: piston skirt, rocker arm cover, valve lifters, cylinder wall and oil pan. The summation of the ratings for the five areas provides an overall rating. Thus, the overall varnish rating can vary from 0 to 50 (50 being clean).

The results of the MS Sequence V-B Test with the polyamine of Experiment (a) are summarized in Table 8.

TABLE 8 ______________________________________ Overall Overall Additive Wt. % Sludge Varnish ______________________________________ None (Control Fuel) 0 28.7 23.7 Experiment (a) polyamine 0.004 32.0 26.8 ______________________________________

EXAMPLE 5

This example illustrates the difference in performance characteristics between the acylated polyalkylene polyamines and cyclic imidazoline compounds. Such a nitrogen-containing cyclic compound was prepared by reacting one molar amount of tetraethylenepentamine with three molar amounts of tall oil fatty acid at 175°C. in the presence of xylene as a solvent. The condensation was carried out until about four molar amounts of water were evolved. The product, after the removal of the solvent, was shown by infrared spectroscopy to contain imidazoline and amide groups.

A. Table 9 shows that the polyamine is effective as a lower engine detergent but the imidazoline is relatively ineffective. The MS Sequence V-B Tests were carried out as described previously.

TABLE 9 ______________________________________ Overall Overall Additive Wt. % Sludge Varnish ______________________________________ None (Control Fuel) 0 28.7 23.7 Imidazoline 0.004 29.1 23.8 Experiment (a) poly- amine 0.004 32.0 26.8 ______________________________________

B. Additionally, it has been found that whereas the polyamine is responsive to an anti-haze additive, the imidazoline is not. One of the ancillary properties required of commercially practical gasoline additives is that the additives do not contribute to emulsion formation or be detrimental to the cleanness of separation of fuel and water. The test (United States Federal Water Rating) is conducted according to the method of ASTM D-1094 wherein the fuel containing an additive is shaken with an aqueous phosphate buffer solution (pH 7) and the condition of the fuel-water interface is noted and rated according to the following:

Rating Appearance of Interface ______________________________________ 1 Clear and clean 1b Small, clear bubbles covering not more than an estimated 50% of the interface and no shreds, lace or film at the interface 2 Shred of lace and/or film at the interface 3 Loose lace and/or slight scum 4 Tight lace and/or heavy scum ______________________________________

Generally, a rating of 1B is required of an acceptable additive. When the additive alone does not meet the required 1B rating, it is a common practice in the industry to use a small amount (0.0002-0.0008% by weight based on the fuel) of a dehaze additive to bring the fuel-water separation rating to 1B or 1. The dehaze compounds are highly polar compounds and include etherified and esterified ethoxylated phenol or amine formaldehyde condensation products. Table 10 shows that the polyamine is responsive to a dehaze agent (to provide a fuel-water separation rating of 1B) whereas the imidazoline is not. The dehaze agent used was commercially available under the trademark "Tolad."

TABLE 10 ______________________________________ Additive (0.004 wt. %) Dehaze Agent Rating ______________________________________ None (Control Fuel) -- 1 Imidazoline None 4 Experiment (a) polyamine None 4 Imidazoline + dehaze agent 0.0004% 4 Experiment (a) polyamine + dehaze agent 0.0004% 1b ______________________________________

EXAMPLE 6

This example demonstrates the effectiveness of the acylated polyalkylene polyamine in combination with an amine carboxylate salt. The amine carboxylate salt was prepared by reacting equal molar amounts of oleylamine containing five (an average) ethylene oxide groups and tall oil fatty acid. The tall oil fatty acid contained 44% oleic, 32% nonconjugated linoleic, 8% conjugated linoleic and 5% saturated (palmitic and stearic) acids and 11% other acids. The concentrates shown in Table 11 were prepared, the amounts indicated being in percent by weight.

TABLE 11 ______________________________________ Concentrate Concentrate Concentrate A B C ______________________________________ Amine carboxylate 80 -- 40 Experiment (a) poly- amine -- 57.1 28.55 Dehaze agent -- 8.6 4.3 Xylene 20 20 20 Isopropanol -- 14.3 7.15 ______________________________________

The concentrates were added to gasoline at various levels and the gasolines were then tested for anti-icing and carburetor detergency performances by procedures described above. The results are summarized in Table 12.

TABLE 12 __________________________________________________________________________ Conc'n. in Fuel (wt. %) Amine Experiment Additive ptb carboxylate (a) polyamine Fuel R Fuel M Fuel S __________________________________________________________________________ A. Carburetor Anti-icing No. of Cycles to Stall None -- -- -- -- 7.6 10.2 Concentrate A 7.5 0.0024 -- 11.6 -- -- Concentrate A 15.0 0.0048 -- 25+ 25+ 25+ Concentrate B 8.75 -- 0.002 6.0 -- -- Concentrate B 17.5 -- 0.004 8.2 -- 25+ Concentrate C 16.25 0.0024 0.002 25+ 25+ 25+ B. Carburetor Detergency (Onan Keep-Clean) Onan Rating None -- -- -- 4.5 4.6 5.0 Concentrate A 15 0.0048 -- 7.9 7.6 6.7 Concentrate B 17.5 -- 0.004 7.9 8.0 8.7 Concentrate C 16.25 0.0024 0.002 7.7 -- 7.9 __________________________________________________________________________ ptb = pounds per thousands barrels Distillation midpoint: Fuel R, 202°F. (94°C.); Fuel M, 201°F. (94°C.); Fuel S, 241°F. (116°C.)

The above results show that the combination provides better carburetor anti-icing protection than would be expected from the results of each component separately. Thus, in Fuel R it is seen that the amine carboxylate salt at the 0.0024% level provides anti-icing protection to 11.6 cycles before stall or an improvement of 7.1 cycles over the control fuel whereas the compound of Experiment (a) at the 0.002% level provides anti-icing protection to 6 cycles before stall or an improvement of 1.5 cycles over the control fuel. The combination of 0.0024% of the amine carboxylate and 0.002% of the compound of Experiment (a), however, provides anti-icing protection of more than 25 cycles before stall. In contrast, it would have been expected that the combination would provide about 13.1 cycles to stall.

Additionally, for carburetor detergency, it can be seen that the combination provides a performance almost equal to that provided by the compound of Experiment (a).

Tests of the above concentrates B and C at 15 pounds per thousand barrels and at 16.25 pounds per thousand barrels, respectively, in six cylinder Chevrolet automobiles under programmed chassis dynamometer Automotive Manufacturers Association (AMA) cycle tests have confirmed the carburetor detergency effectiveness of the compound of Experiment (a) and of the combination exemplified in concentrate C.