Title:
MULTI-FUNCTIONAL GASOLINE ADDITIVES AND GASOLINES CONTAINING THEM
United States Patent 3807976


Abstract:
Hydrocarbon-soluble combinations of: (A) aliphatic C4 to C10 monoamine salts of branched chain primary C8 to C16 alkyl acid esters of orthophosphoric acid; (B) polybutenes having molecular weights in the range 400 to 3000 and viscosities in the range 500 to 900,000 SUS at 100°F. and 60 to 20,000 SUS at 210°F.; and, optionally, (C) hydrocarbon solvents. These mixtures are useful in gasolines for spark ignition engines to inhibit the formation of intake valve deposits and to clean the engine's carburetor.



Inventors:
POLSS P
Application Number:
05/199775
Publication Date:
04/30/1974
Filing Date:
11/17/1971
Assignee:
EI DU PONT DE NEMOURS AND CO,US
Primary Class:
International Classes:
C10L1/14; C10L1/16; C10L1/26; F02B77/04; (IPC1-7): C10L1/22
Field of Search:
44/72,80
View Patent Images:



Primary Examiner:
Wyman, Daniel E.
Assistant Examiner:
Smith, Mrs. Y. H.
Parent Case Data:


This application is a continuation-in-part of Ser. No. 849,925 filed Aug. 13, 1969, now abandoned.
Claims:
The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows

1. A multi-component multi-functional composition for addition to distillate hydrocarbon fuels, said composition consisting essentially of

2. The composition of claim 1 which contains:

3. The composition of claim 1 wherein the amine salt is a substantially neutral salt of a C4 to C8 alkyl primary amine and a C8 to C16 Oxo-alkyl acid ester of orthophosphoric acid.

4. The composition of claim 3 wherein the alkyl groups of said orthophosphoric acid ester have eight to 13 carbon atoms each.

5. The composition of claim 4 wherein the amine salt is the 2-ethylhexylamine salt of a mixture of about 40 to 60 mole percent of tridecyl dihydrogen orthophosphate and about 60 to 40 mole percent of ditridecyl monohydrogen orthophosphate and the polybutene/amine salt weight ratio is between about 1/1 and about 50/1.

6. The composition of claim 4 wherein the amine salt is the isobutylammonium salt of a mixture of about 40 to 60 mole percent of tridecyl dihydrogen orthophosphate and about 60 to 40 mole percent of ditridecyl monohydrogen orthophosphate and the polybutene/amine salt weight ratio is between about 1/1 and 50/1.

7. The composition of claim 3 wherein the polybutene/amine salt weight ratio is between about 5/1 and 30/1.

8. The composition of claim 5 wherein the polybutene is a polyisobutene having a molecular weight in the range 950 to 2700 and a viscosity in the range 40,000 to 890,000 SUS at 100°F. and in the range 1,000 and 19,500 SUS at 210°F.

9. The composition of claim 5 wherein the polybutene is a polyisobutene having a molecular weight in the range 1,200 to 1,400 and a viscosity in the range 100,000 to 125,000 SUS at 100°F. and in the range 2,000 to 3,000 at 210°F.

10. A composition according to claim 2 wherein the amine salt amounts to from about 1.5 to 30 percent by weight of the composition, the polybutene amounts to from about 30 to 80 percent by weight of the composition, and the hydrocarbon solvent amounts to from 10 to 40 percent by weight of the composition.

11. A composition according to claim 10 wherein

12. A composition according to claim 11 wherein

13. A composition according to claim 11 wherein

14. A gasoline comprising an

15. automotive gasoline that normally tends to form induction system deposits in use in spark ignition engines,

16. from about 0.0005 to about 0.008 weight percent based on the gasoline of a gasoline-soluble salt of

17. from about 0.01 to about 0.3 percent by weight based on the gasoline of a normally liquid, gasoline-soluble polybutene having a number average molecular weight in the range 400 to 3000 and a viscosity in the range 500 to 900,000 SUS at 100°F. and in the range 60 to 20,000 SUS at 210°F.,

18. The gasoline composition of claim 14 containing additionally an antiknock quantity of an organolead antiknock agent.

19. The gasoline composition of claim 15 wherein the amine salt amount is between about 0.002 and 0.005 percent, the polybutene between about 0.01 and 0.1 percent, by weight of the composition.

20. The gasoline composition of claim 16 wherein the amine salt is a substantially neutral salt of a C4 to C8 alkyl primary amine and a C8 to C16 Oxo-alkyl acid ester of orthophosphoric acid.

21. The gasoline composition of claim 17 wherein the alkyl groups of said orthophosphoric acid ester have 8 to 13 carbon atoms each.

22. The composition of claim 17 wherein the amine salt is the isobutylammonium salt of a mixture of about 40 to 60 mole percent of tridecyl dihydrogen orthophosphate and about 60 to 40 mole percent of ditridecyl monohydrogen orthophosphate and the polybutene/amine salt weight ratio is between about 1/1 and 50/1.

23. The gasoline composition of claim 17 wherein the amine salt is the 2-ethylhexylamine salt of a mixture of about 40 to 60 mole percent of tridecyl dihydrogen orthophosphate and about 60 to 40 mole percent of di-tridecyl mono-hydrogen orthophosphate, and the polybutene/amine salt weight ratio is between about 5/1 and about 30/1.

24. The gasoline composition of claim 20 wherein the polybutene/amine salt weight ratio is between about 5/1 and about 8/1.

25. The gasoline composition of claim 20 wherein the polybutene/amine salt weight ratio is between about 10/1 and about 14/1.

26. The gasoline composition of claim 20 wherein the polybutene consists essentially of a polyisobutene having a molecular weight in the range 950 to 2700 and a viscosity in the range 40,000 to 890,000 SUS at 100°F. and in the range 1,000 and 19,500 SUS at 210°F.

Description:
BACKGROUND OF THE INVENTION

1. Field of the Invention

Liquid hydrocarbon fuels for spark ignition engines such as present day automotive gasolines are complex mixtures and normally contain relatively unstable, high molecular weight components which tend to deposit on the surfaces of the air-fuel intake system. Naturally occurring sulfur compounds, nitrogen compounds, and polycyclic hydrocarbons, together with additives normally employed in preparing the fuels for commerce, such as antiknock compounds and other agents, contribute to the sludge and deposits that gradually form throughout the induction system of the engine. The increased engine use, these deposits tend to build up causing improper fuel carburetion, improper valve closing, sluggish intake valve action, loss of power and valve burning. Another source of intake system deposits, particularly those found on the intake valve tulips, is the oil which reaches the intake valve tulip by passing between the intake valve stem and the intake valve guide. This oil contains oxidized material and sometimes additives which accumulate on the valve tulip as the result of oxidation and deterioration of the oil and/or evaporation of the oil. This invention relates to multi-functional additives which are effective in inhibiting the formation of such deposits and are also effective as carburetor detergents. More particularly, it relates to novel combinations of selected polybutenes and amine salts of branched chain primary alkyl esters of orthophosphoric acid and to automotive gasolines containing them.

2. Description of the Prior Art

Polybutenes and the amine salts of aliphatic esters of orthophosphoric acid have been individually added to gasoline in the past, but for purposes other than carburetor detergency U.S. Pat. No. 2,049,062 discloses the incorporation of polybutene into gasoline to increase viscosity. U.S. Pat. No. 3,228,758 discloses the use of amine salts of alkyl acid phosphates in distillate fuels, such as gasoline and fuel oils, to inhibit color and haze formation, corrosion of metal by the fuel and the formation of ice in carburetors. The two additives have not been heretofore used together, and they are not particularly noted as materials which inhibit the formation of intake valve deposits. As previously mentioned, polybutenes were considered to be thickeners for gasoline.

SUMMARY OF THE INVENTION

This invention is directed to (1) normally liquid multi-component multi-functional compositions for addition to distillate hydrocarbon fuels and to (2) gasolines containing such compositions, said compositions consisting essentially of

A. a hydrocarbon fuel-soluble salt of

I. a C4 to C10 aliphatic mono- amine wherein each aliphatic radical attached to the amine nitrogen is attached through a saturated carbon atom and

ii. a C8 to C16 branched chain primary alkyl ester of orthophosphoric acid,

B. from 1 to 50 parts by weight per part of (A) of a normally liquid polybutene having a number average molecular weight in the range 400 to 3,000 and a viscosity in the range 500 to 900,000 SUS at 100°F. and in the range 60 to 20,000 SUS at 210°F., and, optionally,

C. a hydrocarbon solvent for (A) and (B) in an amount sufficient to improve the handling characteristics of the composition, said amount corresponding normally to from 10 to 40 percent by weight, preferably about 15 to 30 percent by weight, based on the total composition.

DESCRIPTION OF THE INVENTION

As previously mentioned, the amine salts of alkyl acid phosphates have been added to gasoline to obtain such beneficial effects as anti-icing, corrosion inhibition and stability against haze formation. This invention is based on the discovery that the overall performance of these amine salt additives can be advantageously extended and improved by combination with polybutenes. When the additive combinations of this invention are used in gasoline, they exert a resistance to intake valve deposit formation and a remarkable degree of effectiveness in cleaning up dirty carburetors i.e., carburetors that have accumulated deposits over long periods of use. Thus the compositions of this invention are referred to as multi-functional additives since they provide a wide range of highly advantageous properties to present day motor gasolines.

The polybutene additives of this invention consist essentially of polyisobutenes (i.e., polybutenes wherein each monomer unit in the polymer chain is --C(CH3)2 CH2 -- derived from isobutene), or polybutenes wherein the butylene units are derived from 1-butene or 2-butene, or co-polymers of the various butenes, provided the polybutene is liquid at ordinary temperatures and has a molecular weight and viscosity as defined. For reason of availability and overall characteristics the polyisobutenes are preferred. The term polyisobutene as used herein is meant to include polymers which may have incorporated in the polymer chain minor amounts of 1-butene and 2-butene units. The polyisobutenes are conveniently obtained by polymerizing isobutene or mixtures of isobutene with small amounts of 1-butene and/or 2-butene, according to known methods. Polybutenes which may be used in this invention are commercially available.

The molecular weights referred to herein are number average molecular weights determined by vapor pressure osmometry according to ASTM D-2503. Thus the polybutene additives of this invention having molecular weights in the range of 400 to 3,000 are mixtures of polybutene molecules averaging from about 7 to about 54 C4 H8 units in the polymer chain, with each molecule containing an olefinic double bond, analyzable by titration with bromine according to standard methods, such as ASTM D-1159.

The molecular weight and molecular weight distribution among the polybutene molecules in these mixtures are such that the viscosities of these normally liquid materials range from about 500 SUS at 100°F. and from about 60 SUS at 210°F. for the low (400) molecular weight polymers to about 900,000 SUS at 100°F. and about 20,000 SUS at 210°F. for the high (3000) molecular weight polymers, the viscosities being determined according to ASTM D-445 and 446.

Preferred polybutenes have molecular weights in the range 950 to 2,700 and viscosities in the range 1,000 to 19,500 at 210°F. and in the range 40,000 to 890,000 SUS at 100°F. Most preferably the molecular weights are in the range 1,200 to 1,400, with viscosities in the range 2000 to 3,000 SUS at 210°F. and in the range 100,000 to 125,000 at 100°F. In general, the polymers with molecular weights in the lower end and in the upper end of the overall 400 to 3,000 molecular weight range tend to be less effective in reducing intake system deposits. Mixtures of two or more of the various polybutenes may be used if desired.

The amine salts, useful in this invention, are hydrocarbon soluble materials and preferably for ease of handling are liquid compositions. Such salts may be prepared according to any of a number of methods which are well known in the art. Usually they are prepared by reacting primary alkyl acid phosphates, wherein the primary alkyl groups have from eight to 16 carbon atoms in branched chain configuration, with aliphatic monoamines containing a total of from four to 10 carbon atoms. Normally, a molecule of amine is used for each molecule of monoalkyl dihydrogen phosphate and for each molecule of dialkyl hydrogen phosphate. The resulting salts are generally regarded as substantially neutral, i.e. they exert a pH of between 6 and 7 in water.

The branched chain primary alkyl acid esters of orthophosphoric acid (acid phosphates) will be understood to be those esters in which only 1 or 2 of the three acidic hydrogen atoms of orthophosphoric acid have been replaced by alkyl groups; i.e., they are the monoalkyl dihydrogen phosphates and the dialkyl hydrogen phosphates. Such esters may be obtained according to the general methods of the art which involve reacting an alcohol with phosphorus pentoxide (P2 O5). From about 2 to about 4 moles of the alcohol may be used per mole of P2 O5. Preferably, about 3 moles of the alcohol per mole of P2 O5 is used. When this 3:1 mole ratio of alcohol to P2 O5 is employed, the mixtures are considered to be approximately equimolar mixtures of the mono- and dialkyl esters of orthophosphoric acid. On analysis however, it may be found that the range varies from about 40 to about 60 mole percent of the monoalkyl esters to about 60 to about 40 mole percent of the dialkyl esters. These mixtures of mono- and dialkyl esters are preferred for reasons of economy but other mixtures, as well as the mono- alkyl esters alone or the dialkyl esters alone, may also be used.

For the preparation of the branched chain primary alkyl acid phosphates, the alcohol will be a branched chain primary alcohol having eight to 16 carbon atoms, preferably eight to 13 carbons, or a mixture of two or more of such alkanols. These alcohols preferably will be the branched chain primary alkanols made by the well-known Oxo process from CO, H2 and a branched chain olefin such as the C12 -C15 monoolefinic polymers and interpolymers of propylene and butylene. Such alcohols are disclosed by Smith et al. in U.S. Pat. No. 2,824,836 and by Rudel et al. in U.S. Pat. No. 2,884,379. Examples of preferred Oxo-alcohols that may be used are branched octyl primary alcohols from propylenebutylene interpolymers, branched tridecyl primary alcohols from triisobutylene and from tetrapropylene, and the branched hexadecyl primary alcohols from pentapropylene.

The amines that are used to produce the amine salt component are the aliphatic monoamines containing a total of four to 10 carbon atoms and wherein each aliphatic radical is attached to the nitrogen through a saturated carbon atom. The term "aliphatic monoamine" will be understood to mean a compound which contains only one amino nitrogen to which is attached 1 to 3 aliphatic radicals and is sufficiently basic to form neutral salts with the defined alkyl acid phosphates. The amines may be primary, secondary, or tertiary amines, with the primary amines being preferred. Also, it is preferable to use amines which are water insoluble. The aliphatic radicals attached to the nitrogen may be acyclic (open chain) or alicyclic (cycloaliphatic) radicals. Also, the aliphatic radical may be saturated or unsaturated, provided that the carbon atom attached to the nitrogen atom is a saturated carbon atom, that is, a carbon atom that is not attached to another carbon or to the nitrogen by a multiple bond. The aliphatic amines are generally unsubstituted hydrocarbon amines.

Preferably, the amine will be an alkyl (acyclic, saturated) monoamine of four to eight carbon atoms and most preferably eight carbon atoms. If the amine is a secondary amine, or a tertiary amine, it is preferable that it contain a total of at least eight carbon atoms.

Examples of suitable primary amines are: n-butylamine, isobutylamine, isoamylamine; n-hexylamine; cyclohexylamine; octylamine; 2-ethylhexylamine; and 1,1,3,3-tetramethylbutylamine (t-octylamine). Further examples are t-nonylamine, available commercially and consisting mainly of the C9 amine with small amounts of the C8 and C10 amines. Examples of useful secondary amines are di-n-butylamine, disec.-butylamine, di-isobutylamine, and diamylamine. Examples of suitable tertiary amines are N,N-dimethylcyclohexylamine and N,N-diethylcyclohexylamine.

Any of the above amines can be employed in salt formation with any of the above branched chain alkyl acid phosphates. Preferred, however, are 2-ethylhexylamine, and isobutylamine.

A preferred class of amine salt comprises substantially neutral salts wherein the alkyl acid phosphate component is a mixture of about 40 to 60 mole percent of mono- C8 to C13 -Oxo-alkyl dihydrogen orthophosphate and 60 to 40 mole percent of di- C8 to C13 -Oxo-alkyl monohydrogen orthophosphate. Particulary preferred amine salts are the isobutylamine salt and the 2-ethylhexylamine salt of the above mixture of mono-Oxo-tridecyl dihydrogen orthophosphate and di-Oxo-tridecyl monohydrogen orthophosphate. These are particularly preferred because of their low cost and exceptional detergency effect. Representative and preferred combinations of polybutenes and amine salts are described in the examples below.

An important advantage of this invention is that only small amounts of the low molecular weight polybutenes and of the amine salt components are necessary to exert significant action in cleaning dirty carburetors and inhibiting formation of intake valve deposits in spark ignition engines. The actual quantities required depend on the particular polybutene and amine salt employed, on the fuel and its tendency to form deposits, the extent of deposit accumulation on the engine's carburetor and on the effect desired. Normally there is used sufficient quantities of these two critical components to supply to the gasoline from about 0.01 to about 0.3 percent by weight of the polybutene based on the gasoline and from about 0.0005 to about 0.008 weight percent of the amine salt component based on the gasoline. Often not more than 0.1 percent of the polybutene and not more than 0.005 percent of the amine salt need be used; and usually highly satisfactory results are obtained with from about 0.02 to 0.06 percent of the polybutene and 0.002 to 0.005 percent of the amine salt.

Normally, the proportions of the two critical components are such that there is present from about 1 to 50 parts by weight of the polybutene for every part of the amine salt, preferably between 5 to 30 parts and, most preferably from about 10 to 20 parts. The two components may be added separately to the fuel or they may be added together, for example as a concentrate in a suitable carrier such as a liquid hydrocarbon sufficient to improve the handling characteristics of the composition. Many of the additive combinations of this invention are viscous, and the presence of a solvent makes it easier to pour and mix the materials. For convenience in this respect, the solutions should be concentrated e.g., contain from 10 to 40 percent, preferably 15 to 30 percent, by weight of the solvent. Suitable solvents include those boiling in the gasoline and light hydrocarbon range such as hexane, isooctane, kerosene, toluene and the xylenes. Commerical mixed xylenes is a preferred carrier solvent.

To further illustrate the above proportions and use quantities, representative additive compositions of the invention will normally contain: from about 1.5 to 30 (preferably 3 to 15) percent of the amine salt component; from about 30 to 80 (preferably 60 to 80) percent of the polybutene component; and from 10 to 40 (preferably 15 to 30) percent of hydrocarbon solvent, based on the total composition. Preferred additive compositions of this invention contain: 70 to 75 percent of a polybutene having a 1,260 molecular weight, a 100°F. viscosity of 104,000 SUS and a 210°F. viscosity of 2,460 SUS; 5 to 6 percent of 2-ethylhexylamine salt of a mixture of mono-Oxotridecyl dihydrogen orthophosphate and di-Oxo-tridecyl monohydrogen orthophosphate; and 18 to 24 percent of a hydrocarbon solvent consisting essentially of mixed xylenes. When added to gasoline in amounts of from about 50 to 250 lbs./1000 barrels, which corresponds to from 0.015 to 0.08 percent by weight, this preferred composition supplies from about 0.01 to 0.06 percent of the polybutene and from 0.001 to 0.005 percent of the amine salt. The preferred 75 to 125 lbs./1000 barrels dosage provides from about 0.015 to 0.04 percent of the polybutene and about 0.0015 to 0.003 percent of the salt.

The gasolines useful in this invention can be free of additives other than the polybutene or they can contain antiknock compounds such as organolead antiknock compounds. The organolead antiknock agent can be any of those known to the art for such purpose, but usually will be a lower (C1 -C4) tetraalkyl lead, such as tetramethyl lead, tetraethyl lead, methyl triethyl lead, dimethyl diethyl lead, trimethyl ethyl lead, tetraisopropyl lead, and the like. Mixtures of two or more of such organolead antiknock agents are also useful. The quantity of antiknock agent employed will depend upon the octane number of the base stock and the octane number desired in the finished product. Generally, an amount of antiknock agent is used which will provide about 0.1 to 6 grams of lead for each gallon of the motor fuel, and preferably about 2 to 4 grams of lead per gallon. Preferably, the antiknock agent will be one or more tetraalkyl lead compounds in which the alkyl groups contain 1-2 carbon atoms. The compositions of this invention can also contain varying amounts of conventional fuel additives such as scavenging agents, dyes, antioxidants, anti-icing agents, rust inhibitors, corrosion inhibitors, inhibitors of haze formation, inhibitors of gum formation, anti-preignition agents, and the like. Any of such agents which are chemically and physically compatible with the additive compositions of this invention may be incorporated into these additives.

EXAMPLES

The following Examples illustrate this invention. For convenience, the polybutenes referred to in these Examples are characterized below. Such polymers are commercially available "Oronite" polybutenes. These materials are liquid polymers consisting essentially of polyisobutenes and are characterized by the following properties:

Mol, Viscosity (b) Bromine Polybutene Wt. (a) at 100°F. at 210°F. Number (c) __________________________________________________________________________ I 440 550 63 37 II 730 9500 350 24 III 950 40,000 1,050 18 IV 1260 104,000 2,460 14 V 1400 123,000 2,990 13 VI 2700 890,000 19,500 7 __________________________________________________________________________ (a) Number Average by "MechroLab" vapor pressure osmometry, ASTM D-2503 (b) SUS, by ASTM D-445 and D-446 (c) Grams Br2 /100 grams polymer, by ASTM D-1159

EXAMPLES 1 to 7

The ability of the additive combinations of this invention to clean up a dirty engine is illustrated by the carburetor detergency test described below (involving a deposit accumulation step and a deposit clean-up step) in a fuel having the following inspection data:

A.P.I.° gravity 59.6 Initial b. pt. °F. 88 Recovered, by volume 5% 112° 20% 147° 50% 225° 70% 290° 90% 360° End point 410° Residue, % by vol. 1.0 Aromatics, % by vol. 25 Olefins, % by vol. 8 Saturates, % by vol. 67 Sulfur, Wt. % 0.017 Tetraethyl lead, g/gal 1.41* * includes 0.5 theory ethylenedibromide and 1.0 theory ethylenedichloride

For the test, Polybutenes IV and V described above were blended into samples of the above fuel in a concentration of 0.031 weight percent of the fuel. An amine salt of an alkyl acid phosphate was also blended into the fuel, and in this instance, it was the 2-ethylhexylamine salt of a 1:1 molar mixture of mono-Oxo-tridecyl dihydrogen orthophosphate and di-Oxo-tridecyl monohydrogen orthophosphate prepared according to the procedure of Example 1 of U.S. Pat. No. 3,228,758. The concentration of the amine salt, which is referred to below as 2-ethylhexylammonium tridecyl orthophosphate, was varied as noted in Table I.

DETERGENCY TEST PROCEDURE

A Chevrolet 6 cylinder, 230 cu. in. engine was used having a Carter No. 3511-S 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 ± 10 rpm; water outlet temperature 175 ± 2.5°F.; air/fuel mixture set for maximum vacuum; carburetor air was cooled by passage through an ice tower and then reheated to 90°-95°F.; engine exhaust supply to the carburetor air inlet was controlled as indicated below.

A. Deposit Accumulation (Control Fuel)

New spark plugs were installed, motor oil was changed to an SAE 30 low detergent oil, carburetor, air cleaner housing and 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 engine speed maintained at 700 rpm. The exhaust feed valve setting is critical. This setting was such as to feed the maximum amount of exhaust that the engine would accept and still operate smoothly without stalling. By this method there is produced in the shortest time sufficient throttle body deposit for the clean-up phase of the test.

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. A rating of 100 is clean. If a rating cleaner than "30" was obtained, additional deposit accumulation operation was required.

B. DEPOSIT CLEANUP

The engine conditions are the same as those for (A), except that blowby and exhaust are not fed into the air inlet. The cleanup procedure was followed for 50 hours in five 10-hour segments. Ratings were made at appropriate intervals to determine the amount and speed of cleanup. Percent cleanup was determined as follows:

1. 100 minus rating of deposit accumulation = amount available for cleanup

2. rating after cleanup minus rating of accumulation = amount of cleanup

3. % cleanup = amount of cleanup divided by amount available for cleanup multiplied by 100

Table I ______________________________________ Detergency Test Results 2-Ethylhexylammonium Example Polybutene Tridecyl Phosphate No. mol. wt. wt. % wt. % % clean up ______________________________________ Control 1 -- 0 0 18 Control 2 -- 0 0.0048 17 Control 3 IV 1260 0.031 0 30 1 do. do. 0.031 0.0010 35 2 do. do. 0.031 0.0024 46 3 do. do. 0.031 0.0048 65 4 do. do. 0.031 0.0080 44 Control 4 V 1400 0.031 0 20 5 do. do. 0.031 0.0024 24 6 do. do. 0.031 0.0048 38 7 do. do. 0.031 0.0080 48 ______________________________________

The results show the additive combinations are remarkably effective to clean deposits from dirty carburetors. The cleanup effect is greater than "additive;" i.e. greater than that expected from the performance of either the polybutene or the amine salt alone. The clean-up effect is particularly pronounced with the 1,260 molecular weight polybutene which, at the concentrations employed, shows peak performance at a polybutene/amine salt ratio in the range of about 5/1 to 13/1.

EXAMPLES 8 TO 11

Other additive combinations were tested by the procedures outlined above for examples 1 to 7 using a fuel having the following inspection data:

A.P.I.° gravity 59.4 Initial b. pt., °F. 96 Recovered, by volume 5% 114° 20% 138° 50% 201° 70% 259° 90% 341° End point 410° Residue, % by vol. 1.0 Aromatics, % by vol. 25 Olefins, % by vol. 12 Saturates, % by vol. 63 Sulfur, % by wt. 0.068 Tetraethyl lead, g./gal 2.53* * includes 0.5 theory ethylene dibromide and 1.0 theory ethylenedichloride.

For the test the samples and fuel were blended as described above for examples 1 - 7 and the results are shown below in Table II.

Table II __________________________________________________________________________ Detergency Test Results Example Polybutene Amine Salts Clean up No. mol. wt. wt. % No. wt. % % __________________________________________________________________________ Control 1 -- -- 0 -- 0 17 Control 2 V 1400 0.031 -- 0 13 Control 3 -- -- 0 A 0.0048 17 8 V 1400 0.031 A. 0.0048 56 Control 4 -- -- 0 B 0.0048 29 9 V 1400 0.031 B 0.0048 36 Control 5 -- -- 0 C 0.0048 14 10 V 1400 0.031 C 0.0048 26 Control 6 -- -- 0 D 0.0048 28 11 V 1400 0.031 D 0.0048 24 __________________________________________________________________________

In the above tests the amine salts designated A through D were as follows:

Designation ______________________________________ A isobutylammonium oxi-tridecylphosphate B 2-ethylhexylammonium oxo-tridecylphosphate C 2-ethylhexylammonium oxo-octylphosphate D 1,1-dimethyl C10-12 ammonium oxo-octylphosphate. ______________________________________

The results show that the additive combinations of this invention, examples 8, 9 and 10 display carburetor detergency that is greater than the additive effect of the components alone, while an additive combination outside the scope of this invention, example 11, actually shows antagonism in the combined result.

EXAMPLES 12 TO 20

To illustrate the effectiveness of the additive combinations of this invention in preventing intake valve deposits, polymers III through VI above were blended, in concentrations ranging from 0.012 to 0.124 weight percent, as more fully exemplified below, into samples of a motor gasoline having a tendency to form intake valve deposits under both ordinary and severe driving conditions. Also blended into the fuel samples was 2-ethylhexylammonium tridecyl phosphate (described above) in concentrations of 0.0024 and 0.0048 weight percent based on the fuel. The gasoline's inspection data was as follows:

A.P.I.° gravity 58.9 Initial b. pt., °F. 92 Recovered, by volume 5% 114° 20% 149° 50% 215° 70% 266° 90% 348° End point 410° Residue, % by vol. 1.0 Aromatics, % by vol. 24 Olefins, % by vol. 15 Saturates, % by vol. 61 Sulfur, Wt. % 0.141 Tetraethyl lead, g./gal 3.27* * includes 0.5 theory ethylene dibromide and 1.0 theory ethylene dichloride per mole of tetraethyl lead.

The effectiveness of the additive combination of this invention in the above described gasoline was determined in two intake valve deposit tests -- one (designated test A) simulating ordinary driving conditions, the other (designated Test B) being a relatively severe, high-speed, heavy-duty test.

Chevrolet Intake Valve Deposit Test

TEST A

The engine used was a 1968, 250 cubic inch, 6 cylinder Chevrolet engine equipped with "Power-Glide" transmission and inertia flywheel. The engine was on a test stand equipped with a dynamometer to absorb the power output. The heads were completely reconditioned, deposits removed from piston tops and the carburetor overhauled. New PCV valve, spark plugs, points and gasoline filter were installed. The oil filter was changed and 10W-30 oil put in.

The test was performed by operating the engine for 100 one hour cycles. Each cycle consisted of the following conditions designed to similate stop-and-go on-the-road conditions including moderate and high speed driving alternating with stopped periods with the engine running such as at a traffic light.

______________________________________ Time Interval Engine Speed, Dyno Speed, (mins.) rpm rpm Throttle ______________________________________ 0-5 -- 1300±50 Idle-WOT* 5-8 600 -- Idle 8-12 -- 1700±50 Idle-WOT* 12-15 600 -- Idle 15-18 -- 2050±75 Idle-WOT* 18-21 600 -- 21-26 -- 1300±50 Idle 26-29 600 -- Idle-WOT* 29-34 -- 2800±75 Idle 34-60 600 -- Idle-WOT* ______________________________________ * 5 sec. idle, 5 sec. wide open throttle The engine coolant fluid inlet and outlet temperatures, the engine oil temperature and pressure, the transmission oil temperature and the engine and dynamometer speeds were continuously recorded. The oil and spark plugs were changed at 50 hours.

At the end of the 100 cycles, the intake valves were removed, washed with pentane, dried and weighed. These valves were then cleaned by scraping off the tulip deposit and weighed again. Table III reports results obtained.

Table III __________________________________________________________________________ Chevrolet Intake Valve Deposit Test - TEST A __________________________________________________________________________ Amine Phos- Polymer phate Salt* Valve Deposit Ex. No. mol. wt. wt. % wt.% wt. g. (avg.) __________________________________________________________________________ Con- trol -- -- 0 0 1.28 12 III 950 0.062 0.0024 0.22 13 IV 1260 0.031 0.0024 0.32 14 IV 1260 0.031 0.0048 0.51 15 V 1400 0.031 0.0024 0.19 16 V 1400 0.012 0.0024 1.10 17 VI 2700 0.031 0.0024 0.31 __________________________________________________________________________ * 2-ethylhexylamine salt of mixed mono- and di-(Oxo)tridecyl acid phosphate described in Examples 1-7.

Buick Intake Valve Deposit Test

TEST B

The engine used was a 401 CID Buick with export pistons and an extra head gasket (i.e., a low compression package) so that the engine was capable of operating on lower octane fuels such as are more commonly used in Europe. The carburetor was a Carter AFB carburetor with the interconnecting passageways between the barrels sealed so that two fuels could be introduced and tested simultaneously. This engine, which was without transmission and inertia flywheel, was mounted on a test stand and a dynamometer was used to provide the load. The heads were completely reconditioned, deposits removed from the piston tops and carburetor overhauled. New PCV valve, spark plugs, points and gasoline filter were installed. The oil filter was changed and 10W-30 oil put in.

The test was performed by operating the engine for 110 hours, repeating the following idle-load cycle.

______________________________________ Operation (repeated for Idle Load 110 hours) ______________________________________ Time-Interval in seconds 60 196 Speed, rpm 2000 ± 25 2800 ± 25 Torque, ft. lbs. 0 75 Air-Fuel Ratio 12.0:1 ± 1.0 14.0:1 ± 0.5 ______________________________________

The oil and spark plugs were changed at 60 hours. The engine coolant fluid inlet and outlet temperatures, the engine oil temperature and pressure, the engine speed and dynamometer load and the fuel flow and the intake manifold vacuum continuously recorded. The air fuel ratio was checked and recorded every eight hours.

At the end of 100 hours, the intake valves were removed, washed with pentane, dried and weighed. These valves were then cleaned by scraping off the tulip deposit and weighed again. Table IV reports the results obtained.

Table IV __________________________________________________________________________ Buick Intake Valve Deposit Test - TEST B __________________________________________________________________________ Amine Phos- Polymer phate salt* Valve Deposit Ex. No. mol. wt. wt.% wt., % wt., g __________________________________________________________________________ Con- trol -- 0 0 1.96 18 III 950 0.124 0.0048 1.16 19 IV 1260 0.031 0.0024 0.79 20 IV 1260 0.062 0.0024 0.47 __________________________________________________________________________ * 2-ethylhexylamine salt of mixed mono- and di(Oxo)tridecyl acid phosphat as described in Examples 1-7

The results of Tests A and B in conjunction with the detergent test show that the additive combination is effective not only as a carburetor detergent but also as an agent to inhibit formation of intake valve tulip deposits.

In addition to the additive combinations disclosed in the Examples, there are various other combinations of amine salts and polybutenes that are suitable in this invention. For example, a preferred polybutene-amine salt additive composition can be prepared by blending together 72.5 parts of polybutene V, 7.5 parts of 2-ethylhexylamine salt of mixed mono- and di-Oxo-tridecyl hydrogen orthophosphates prepared according to Example 1 of U.S. Pat. No. 3,228,758 as a 80 percent wt. concentrate in kerosene (thus providing 6 parts of the amine salt to the combination), and 20 parts of commercial mixed xylene. This is a mobile liquid suitable for addition to gasoline. Also the aforementioned 2-ethylhexylamine salt of mixed mono- and di-Oxo-tridecyl hydrogen phosphate can be used with the polybutenes designated as I and II at the beginning of the Examples. Another preferred combination of polybutene V and the 2-ethylhexylamine salt described above is 67.5 parts polybutene, 14 parts amine salt concentrate (containing 2.8 parts kerosene) and 18.5 parts xylene. It should also be pointed out that amine salts other than those previously disclosed can be used. Among these are amine salts of approximately 1:1 molar mixtures of monoalkyl dihydrogen phosphates and dialkyl monohydrogen phosphates, prepared as concentrates in kerosene, according to the procedure described in Example 1 of U.S. Pat. No. 3,228,758.