US3506712A - Quaternary amine salts useful as fuel stabilizers - Google Patents

Description

United States Patent 3,506,712 QUATERNARY AMINE SALTS USEFUL AS FUEL STABILIZERS Julius Capowski and Harry J. Andress, Jr., Pitman, N.J., assignors to Mobil Oil Corporation, a corporation of New York No Drawing. Original application Aug. 31, 1964, Ser. No. 393,351, now Patent No. 3,387,954, dated June 11, 1968. Divided and this application Oct. 6, 1966, Ser. No. 584,680

Int. Cl. C07c 87/30; Cl 1/22 US. Cl. 260567.6 3 Claims ABSTRACT OF THE DISCLOSURE Alkylamine salts having the formula:

R2 l R3]nX where R R R and R are alkyl groups having from 1 to about 22 carbon atoms, and X is an acid radical of phosphoric acids having from 2 to 8 phosphorus atoms per molecule and n is a whole number from 1 to 5, the maximum value of n being limited by the number of replaceable hydrogen atoms in the acid molecule of which X is an acid radical. These compounds find utility as fuel stabilizers.

This application is a division of our copending application Ser. No. 393,351, filed Aug. 31, 1964, now US. Patent 3,387,954, June 11, 1968, and the invention therein relates to liquid hydrocarbon fuels. More particularly, the invention relates to liquid hydrocarbon combustion fuels that are stabilized against screen-clogging, filter plugging, sediment formation, icing and corrosion, and the novel additive compounds useful for such purposes.

As is well known to those skilled in the art, liquid hydrocarbon fuels, particularly hydrocarbon combustion fuels, such as fuel oils, diesel fuels, jet fuels and gasolines, tend to exhibit certain deleterious characteristics either after long periods of storage or under the conditions of operational use. Thus, it has been found that in such fuels, apart from the fact that under storage or operational conditions they may exhibit icing, corrosion and sediment formation, a particularly serious problem is encountered in the clogging of screens and plugging of filters. This tendency to clog screens and plug filters results from the caustic treatment of catalytically refined petroleum distillate fuels for the removal of sulfur-containing materials.

More specifically, this condition occurs when certain polar materials (surface-active additives and trace constituents) in the fuel contacted by the caustic agents, break down and form, as part of the product, water-soluble alkali metal compounds. When, subsequently, these fuels contact water such as might be present in fuel tank bottoms, these alkali metal compounds are leached out of the hydrocarbon phase into the water phase to greater or lesser degrees. There, by replacement of the alkali metals, corresponding compounds of dissolved metals having normal valences greater than-one (for e.g. calcium, magnesium, zinc, copper, iron, aluminum, barium or lead) may be formed. Because of their surface activity, and reduced water and product solubility, these compounds may cause emulsification and gel formation particularly in the hydrocarbon layer, as well as in the water layer, with consequent serious detrimental effects on the clogging of screens and the plugging of filters. Heretofore, certain organic amine monophosphates have been suggested as anti-icers, carburetor detergents and anti-rust agents; however, these additives have, nevertheless, been found to cause serious problems with respect to the aforementioned screen clogging and filter plugging conditions. Accordingly, a means for stabilizing such fuels and protecting them against the aforementioned screen clogging, filter plugging, as well as other undesirable storage conditions normally encountered, is highly desirable.

It is, therefore, an object of the present invention to provide improved liquid hydrocarbon fuels.

Another object of the invention is to provide improved liquid hydrocarbon combustion fuels and means for protecting them, which are effective not only against sediment formation, icing and corrosion, but also against screen-clogging and filter plugging.

Other objects and advantages inherent in the invention will become apparent to those skilled in the art from the following description.

In accordance with the present invention, as more fully hereinafter described, it hasbeen found that the above objects can be attained by the addition of small amounts of additive compositions having the formula:

where R R R and R are alkyl groups having from 1 to about 22 carbon atoms, and preferably, from about 8 to about 18 carbon atoms, X is an acid radical selected from the group consisting of (a) phosphoric acids having from 2 to 8 phosphorus atoms per molecule, (b) phosphoric acid alkyl esters having from 2 to 8 phosphorus atoms per molecule and containing from 1 to 4 alkyl groups having from 1 to 22 carbon atoms per alkyl group, (c) boric acid, ((1) carbonic acid, (e) aminopolycarboxylic acids and hydroxyethyl aminocarboxylic acids, in which the amine nitrogen atom is separated from the carboxylic carbon atom by a methylene or ethylene linkage and in which when more than one nitrogen atom is present they are separated from each other by ethylene or propylene linkages, and n is a whole number from 1 to 5, the maximum value of n being limited by the number of replaceable hydrogen atoms in the acid molecule of which X is an acid radical.

More specifically, with respect to the aforementioned substituents for the acid radical X, phosphoric acids of the type indicated under (a) may include pyrophosphoric acid (diphosphoric acid), triphosphoric acid, hexaphosphoric acid and polyphosphoric acid. Aminopolycarboxylic acids of the type indicated under (e) may include ethylenediamine tetraacetic acid, nitrilotriacetic acid, diaminocyclohexane -N,N- tetraacetic acid, and diethylenetriamine pentaacetic acid. Hydroxyethyl aminocarboxylic acids indicated under (e) may include N-hydroxyethyl ethylenediamine triacetic acid and dihydroxyethyl glycine.

As will become hereinafter apparent, these additive compositions are particularly effective not only as stabilizers against icing, corrosion and sediment formation, but also as anti-screen clogging and filter plugging agents in liquid hydrocarbon fuels.

These beneficial eifects result from the fact that in the previously described replacement of the alkali metals, those metals having valences greater than one are tied up and rendered unavailable. As a result of such action, the aforementioned detrimental effects are prevented from occurring.

The alkylamine salt additives are, in general, prepared by reacting one equivalent of the selected amine with one equivalent of the selected acid, in accordance with the above-described general formula, preferably at elevated 3 temperature, for example, from about 50 C. to about 120 C.

The aforementioned alkylamine salt additives may be used to improve liquid hydrocarbon fuels, generally. Of particular significance is the use of these additives to improve liquid hydrocarbon fuels comprising petroleum distillates, which are hydrocarbon fractions, having an initial boiling oint of at least about 90 F. and an end boiling point not higher than about 750 F., and boiling substantially continuously throughout their distillation range. Such fuels are generally referred to as distillate fuel oils. It will be understood, however, that this terminology is not restricted to straight-run distillate fractions. The distillate fuel oils may comprise straight-run distillate fuel oils, catalytically or thermally cracked (including hydrocracked) distillate fuel oils, or mixtures of straight-run distillate fuel oils, naphthas and the like, with cracked distillate stocks. Moreover, such fuel oils can be treated in accordance with well known commercial methods, such as, acid or caustic treatment, hydrogenation, solvent refining, clay treatment and the like.

The distillate fuel oils are characterized by their relatively low viscosities, pour points and the like. The principal property which characterizes the contemplated liquid hydrocarbon fuels of the present invention, however, is their distillation range. As previously indicated, this range will lie between about 90 F. and about 750 F. Obviously, the distillation range of each individual fuel oil will cover a narrower boiling range, falling, nevertheless, within the above-specified limits. Likewise, each fuel oil will boil substantially continuously throughout its distillation range.

Particularly contemplated among the aforementioned liquid hydrocarbon fuel oils are gasolines, Nos. 1, 2 and 3 fuel oils used in heating, diesel fuel oils, and the jet combustion fuels. The gasolines generally boil within the range from about 90 F. to about 450 F. The domestic fuel oils generally conform to the specifications set forth in ASTM Specifications D396-62T. Specifications for diesel fuels are defined in ASTM Specifications D975-60T. Typical jet fuels are defined in Military Specifications MIL-F-5624B.

The amount of the aforementioned alkylamine salt additive contemplated for use herein which is added to the liquid hydrocarbon fuel will depend, of course, upon the intended and the particular additives selected, inasmuch as these additives are not equivalent in their activity. Certain of these additives may necessitate being used in greater concentrations than others to be effective. In most cases, in which it is desired to obtain the aforementioned beneficial results in the liquid hydrocarbon fuels, viz prevention of clogging of screens and plugging of filters, in addition to stabilization against sediment formation, icing and corrosion, additive concentrations varying from about 1 to about 200 pounds per thousand barrels of the fuel will be employed. Preferably, it will vary from about 5 to about pounds per 100 barrels of fuel. If so desired, the aforementioned liquid hydrocarbon fuel compositions of the present invention can contain other additives for the purpose of achieving other results. Thus, for example, there may be present foam inhibitors, ignition and burning quality improvers, and others. Examples of such additives are silicones, dinitropropane, amyl nitrate, metal sulfonates, and the like.

The following examples and comparative data are intended to illustrate the novel additive compositions of the present invention and also to demonstrate their effectiveness in improving the properties of liquid hydrocarbon fuels. It will be understood, of course, that it is not intended the invention be limited to the particular compositions shown or to the operations or manipulations involved. Various other additive compositions, and other fuels, can be utilized as those skilled in the art will readily appreciate.

In carrying out the comparative experimentation, previously referred to, laboratory bench tests were made in which 40 ml. of an average commercially available gasoline blend (comprising, by volume,--40% -catalytically cracked, 40% reformate and 20% alkylate components), was treated with 10 ml. of 0.8 N NaOH (as a sulfur compound, particularly mercaptan, removing agent), 6 ml. of distilled water and 20 ml. of 13.6 g./l. of ZnCl solution (a component providing zinc ions which are often present in the field in tank water bottoms as a result of chemical actions on galvanized metal surfaces) in a 100 ml. mixing graduate. This mixture was given fifteen uniform, moderate, shakiugs and allowed to settle for one minute. The mixture was then examined for indications of colloidal states. The following table indicates the results obtained in such examinations. With regard to this table, it should be noted that the laboratory tests simulate the most severe conditions of commercial use that would normally be expected to result in emulsion and gel formation, which would otherwise cause handling difliculties in product distribution systems and in vehicle fuel lines, with particular emphasis residing in encountering screen clogging and filter plugging. As will be seen from the table, under such conditions the additives of the present invention reduced, to a very significant degree, the tendency of the uninhibited gasoline and the uninhibited gasoline containing an alkylamine monophosphate (as a typical anti-icer, anti-rust and carburetor detergent multifunctional additive) to form emulsions.

The additives of the following table were prepared as follows:

EXAMPLE I Preparation of dicoco dimethylammonium pyrophosphate A mixture comprising: 200 grams of dicoco dimethylammonium chloride and containing 25 percent isopropanol and having a combining weight of about 475; 35 grams of sodium pyrophosphate decahydrate having an equivalent weight of 111.5; 1 00 grams of water; and 200 grams of benzene, was refluxed to a temperature of about 195 C. over a period of 8 hours. The resulting reaction mixture was then filtered to remove sodium chloride and topped at 180 C. under reduced pressure to yield the desired dicoco dimethylammonium pyrophosphate additive.

EXAMPLE II Preparation of dicoco dimethylammonium salt of ethylenediamine tetraacetic acid A mixture comprising: 280 grams of dicoco dimethylammonium chloride and containing 25 percent isopropanol and having a combining weight of about 475; 42 grams of the tetrasodium salt of ethylenediamine tetraacetic acid having a molecular weight of 380 and an equivalent weight of 50 grams of water; and grams of benzene was refluxed to a temperature of C. until the evolution of water had ceased, viz approximately 8 hours. The resulting reaction mixture was then filtered and topped to yield the dicoco dimethylammonium salt of ethylenediamine tetraacetic acid additive.

EXAMPLE III Preparation of disoya dimethylammonium salt of tripolyphosphoric acid A mixture comprising: 220 grams of disoya dimethylammonium chloride containing 25 percent isopropanol and having a combining weight of about 580; 21 grams of sodium tripolyphosphate (Na P O having an equivalent weight of 74; 50 grams of water; and 100 grams of benzene was refluxed to a temperature of about C. over a period of 8 hours. The resulting reaction mixture was filtered and topped to yield the desired disoya dimethylammonium salt of tripolyphosphoric acid additive.

TABLE Demulsification test Gasoline Concentration layer, percent lbs./ 1,000 bbls. emulsified Water layer, observations (1) Blank gasoline l 40 Cloudy with heavy precipia e. (2) Blank gasoline plus a commercial alkylamine 100 80 Cloudy with moderate premonophosphate. cipitate. Blank gasoline plus dicoco dimethylam- 100 Cloudy with slight precipimonium pyrophosphate. tate. (4) Blank gasoline plus dicoco dimethylam- 100 5 Slightly cloudy.

moiium salt of ethylenediamine tetraacetic acl (5) Blank gasoline plus disoya dimethylam- 100 Clear with slight precipitate.

monium salt of tripolyphosphoric acid.

1 A commercial type catalytically eracked/reforrnate/alkylate gasoline blend containing 5 lb./l,000 barrels 2,6- ditertiary butyl paracresol; l lb./1,000 barrels N,N-disalicylidene-1,2-propanediam1ne; and 3 cc. tetraethyl lead/gal.

While the present invention has been described with preferred embodiments, it should be understood that modifications and variations thereof may be resorted to without departing from the spirit of the invention as will be obvious to those skilled in the art.

We claim:

1. Alkylamine salts selected from the group consisting of dicoco dimethylammonium pyrophosphate and disoya dimethylammonium salt of tripolyphosphoric acid.

2. An alkylamine salt as defined in claim 1, wherein said salt is dicoco dimethylammonium pyrophosphate.

3. An alkylamine salt as defined in claim 1, wherein References Cited UNITED STATES PATENTS 2,805,203 9/1957 Knapp et al 260501.11 2,830,019 4/1958 Fields et a1. 260-50-1.1l 3,005,012 10/ 1961 Mulloy 260567.6 3,033,665 5/1962 Gaston et a1 4466 3,121,091 2/1964 Green 260- 567.6

3,321,521 5/1967 Kerr 260-501.11

FOREIGN PATENTS 786,758 11/1957 Great Britain.

said salt is disoya dimethylammonium salt of tripoly- LEON ZITVER Primary Examiner phosphoric acid.

M. W. GLYNN, Assistant Examiner