US3758283A - Conductivity additive for liquid hydrocarbons - Google Patents

Abstract

A COMPOSITION CONSISTING ESSENTIALLY OF A TRIVALENT CHROMIUM SALT OF AN ORGANIC PHOSPHATE, A NITROGEN CONTAINING COPOLYMER AND AN AMINE NEUTRALIZED ALKYL PHOSPHATE INCREASES THE CONDUCTIVITY OF LIQUID HYDROCARBONS AND PREVENTS ACCUMULATION OF STATIC CHARGE IN HYDROCARBON FUELS AND SOLVENTS.

Description

United States Patent Int. Cl. C101 1/26 US. C]. 44-62 4 Claims ABSTRACT OF THE DISCLOSURE A composition consisting essentially of a trivalent chromium salt of an organic phosphate, a nitrogen containing copolymer and an amine neutralized alkyl phosphate increases the conductivity of liquid hydrocarbons and prevents accumulation of static charge in hydrocarbon fuels and solvents.

BACKGROUND OF THE INVENTION (1) Field of the invention This invention relates to an additive composition for liquid hydrocarbons, said additive consisting essentially of a trivalent chromium salt of an organic phosphate, a nitrogen containing copolymer and an amine neutralized alkyl phosphate. This invention also relates to hydrocarbon liquid containing this additive composition.

(2) Descrption of the prior art Hydrocarbon liquids, both aliphatic and aromatic, distillate fuels and jet fuels and tend to accumulate a potentially hazardous electrostatic charge. A number of explosions and fires have occurred in recent years during the bulk handling and transporting of gasolines, kerosene, jet fuels, fuel oils, and hydrocarbon solvents having boiling points between about 70 F. and 700 F. These explosions have been attributed to the accumulation and subsequent discharge of static electricity in systems involved. Some handling conditions which contribute to the rapid generation of dangerous charge levels are rapid flow of fuel through pipelines and hoses, splash filling of receiving vessels, such as storage tanks and seagoing tankers, and refueling of jet aircraft.

Various additives have been proposed to minimize the accumulation of static electricity by increasing the conductivity of the hydrocarbon solvent or fuel. These additives should be effective in small concentrations and have no adverse effects on the hydrocarbon products, especially jet fuels, where stringent specifications have to be met.

A number of metal salts of carboxylic acids, as shown in US. Patent No. 3,012,969, and organic phosphate salt compositions, as shown in US. Patent No. 3,256,073, are useful in increasing the conductivity of volatile solvents and fuel oils. Although these metal salts increase the conductivity appreciably, their effectiveness tends to be short-lived, a substantial portion being lost on storage.

In order to avoid this loss, it was proposed in US. Patent No. 3,013,868 to mix a polymer with a chromium carboxylate. The polymer, preferably a nitrogen containing acrylate or methacrylate copolymer, prolonged the conductivity level of the chromium carboxylates.

The conductivity level of some chromium salts of alkyl phophates was also found to be prolonged by the addition of nitrogen containing copolymers. However, the advantage obtained by incorporating the copolymer is ofiset by the fact that the salt-copolymer mixtures form gels, and thus can not be readily put to practical use. I have now found that a conductivity additive consisting of a chromium salt of an alkyl phosphate and a nitrogen containing copolymer can be rendered liquid and maintained in the liquid state while still retaining a high conductivity 3,758,283 Patented Sept. 11, 1973 level, by incorporating an amine neutralized alkyl acid phosphate.

SUMMARY OF THE INVENTION In summary, this invention is directed to a composition for increasing the conductivity of hydrocarbon liquids consisting of essentially of (1) one part by weight of a trivalent chromium salt of (a) an alkyl phosphate, said salt having the formula wherein R and R can be the same or different and R is alkyl of 1 to 1-6 carbon atoms, alkylphenyl wherein the alkyl contains 1 to 1-6 carbon atoms, or phenyl, and

R is alkyl of 3 to 16 carbon atoms, alkylphenyl wherein the alkyl contains 1 to 16 carbon atoms, or phenyl; or

(b) a mixture of (i) 60 to 40 mol percent of a monohydrocarbon dihydrogen phosphate, and

(ii) 40 to 60 mol percent of a dihydrocarbon monohydrogen phosphate,

wherein the hydrogen is alkyl of 4 to 16 carbon atoms, alkylphenyl the alkyl contains 1 to 16 carbon atoms, or phenyl (2) from .5 to 1 part by weight of an oil soluble copolymer wherein (a) one of the monomers is amine-free;

(b) one of the monomers contains from 8 to 18 carbon atoms in an aliphatic hydrocarbon chain which is not part of the polymer chain;

(c) one of the monomers contains a basic amino nitrogen which is not itself part of the polymer chain; and

(d) each of the monomers, prior to polymerization, contains a carbon-carbon double bond capable of participation in free radical initiated addition copolymerization;

said copolymer containing from 0.1 to 3.5 weight percent of basic amino nitrogen; and

(3) from .5 to 16 parts by weight of an oil soluble salt (a) a 2 to 24 carbon atom monoamine selected from among (i) tertiary alkyl primary amines;

(ii) secondary amines having 2 mono-valent satuarted hydrocarbon radical substituents; and

(iii) tertiary amines having 3 mono-valent sat-urated hydrocarbon radical substituents; and

(b) mixed monoalkyl acid phosphates and dialkyl acid phosphates wherein the alkyl groups contain 8 to 18 carbon atoms.

This invention is further directed to concentrated solutions of the above compositions in liquid hydrocarbonmiscible solvents and to the above compositions in liquid hydrocarbons.

The composition of this invention are effective in raising the conductivity level of a hydrocarbon liquid, such as jet fuel or fuel oil, and maintains a substantial portion of of its initial level of effectiveness in the liquid hydrocarbon during storage. Another particular advantage of the compositions of this invention is that the components remain in the oil phase during storage of the fuel, even in the presence of small amounts of water; thereby retaining their effectiveness. Moreover the compositions of this invention minimize sludge formation and enhance thermal stability of fuel oils.

DESCRIPTION OF THE INVENTION As stated above, this invention is directed to an additive composition for liquid hydrocarbons consisting essentially of a trivalent chromium salt of an organic phosphate, a nitrogen containing copolymer, and an amine neutralized alkyl phosphate. The three components and their relative concentrations in the compositions as well as their method of preparation are described below.

(1) Components of the additive compositions (A) Chromium phosphate.The phosphate salts of chromium useful in this invention are the trivalent chromium salts of alkyl phosphates having the formula wherein R and R can be the same or different and R is alkyl of l to 16 carbon atoms, alkylphenyl wherein the alkyl contains 1 to 16 carbon atoms, or phenyl, and R is alkyl of 3 to 16 carbon atoms, alkylphenyl wherein the alkyl contains 1 to 16 carbon atoms, or phenyl; and the trivalent chromium salts of mixtures of 60 to 40 mol percent of a monohydrocarbon dihydrogen phosphate and 40 to 60 mol percent dihydrocarbon monohydrogen phosphate wherein the hydrocarbon is alkyl of 4 to 16 carbon atoms, alkylphenyl wherein the alkyl contains 1 to 16 carbon atoms or phenyl.

Representative of suitabe chromium organic phosphates are the Cr(III) salts of di-substituted monohydrogen phosphates such as di-isooctyl phosphate; di-Z-ethylhexyl phosphate; di-decyl phosphate; di-dodecyl phosphate; di-tridecyl phosphate; di-hexadecyl phosphate; diphenyl phosphate; di-p-ethylphenyl phosphate; di-p-nonylphenyl phosphate; di p hexadecylphenyl phosphate; methyl isooctyl phosphate; ethyl isopropyl phosphate; ethyl isooctyl phosphate; methyl-Z-ethylhexyl phosphate; methyl phenyl phosphate; ethyl n-octyl phosphate; ethyl Z-ethylhexyl phosphate; methyl p-ethylphenyl phosphate; and methyl hexadecyl phosphate; and the Cr(III) salts of mixed, substituted, acid phosphates wherein the substituents can be for example isooctyl, n-octyl, Z-ethylhexyl, dodecyl, tridecyl, hexadecyl, phenyl, p-ethylphenyl and pnonylphenyl.

Preferred chromium phosphates are those of Formula 1 above wherein R and R are alkyl and most preferred are those salts wherein R and R are branched chain primary alkyls of 8 to 16 carbon atoms.

The chromium tri-phosphate salts can be conveniently prepared for example by heating one mole of a salt of trivalent chromium, such as the triacetate, tripropionate, or tributyrate salt, in a hydrocarbon solvent, such as toluene or benzene, with 3 moles of the desired hydrocarbon phosphate at reflux. The by-product acid, for example acetic, propionic or butyric, is distilled ofi, and the product chromium triphosphate salt is isolated from the reaction mass by distillation of the solvent.

The chromium salts can also be obtained by reaction of chromium chloride with the appropriate phosphate as illustrated hereinafter in the examples.

(B) Nitrogen-containing polymers-The polymers suitable for use in the present invention are oil-soluble copolymers derived from at least two different polymerizable compounds, one of which must be amine-free, one of which must contain from 8 to about 18 carbon atoms in an aliphatic hydrocarbon chain which in the polymer is not part of the main polymer chain, (thereby providing an oleophilic structure) and one of which must contain a basic amino nitrogen structure, also not a part of the main polymer chain. The copolymers must contain at least 0.1% but not more than 35%, by weight of basic amino nitrogen, and preferably between 0.2% and 3.0%. The polymer need not be derived from only two different polymerizable compounds as illustrated above but can also contain one or more additional polymerizable compounds that do not by themselves form oil-soluble polymers. The latter is true providing the proportions are restricted to insure that (a) the polymers have the requisite oil solubility and(b) no substantial change occurs in the valuable properties of these polymers as sludge inhibitors and dispersants. A basic requirement is that the copolymer formed must have at least a limited solubility in the hydrocarbon liquid, i.e., at least 0.001% by weight. The term oil-soluble is used herein to denote a solubility of at least 0.001%, by Weight, in the liquid hydrocarbon. It is also preferable that the copolymer have an inherent viscosity of between 0.1 and 3.0 as determined at 0.1% weight-volume concentration in benzene at 25 C.

As the oleophilic components of copolymers useful in the preparation of the compositions of this invention there can be employed polymerizable esters, amides, ethers, and hydrocarbons characterized by the presence of at least 8 carbon atoms, preferably with 6 or more in a straight chain, and at least one carbon-carbon double bond capable of participation in free radical initiated addition copolymerization reactions. Examples of oleophilic components suitable for use are: saturated and unsaturated longchain esters of unsaturated carboxylic acids such as 2- ethylhexyl, acrylate, decyl acrylate, 3,5,5-trimethylhexyl methacrylate, 9-octa-decenyl methacrylate; unsaturated esters of long-chain carboxylic acids such as vinyl stearate; long-chain esters of vinylene dicarboxylic acids such as methyl lauryl fumarate; N-long-chain hydrocarbon substituted amides of unsaturated acids such as N-octadecyl acrylamide; and long-chain monoolefins such as the alkyl or acyl substituted styrenes, e.g., dodecylstyrene. Obviously, these components can be employed alone or in various combinations and, in general, make up the majority of the polymeric additive in order to insure proper oleophilic chanacter. The technical lauryl methacrylate obtained from the commercial mixture of long-chain alcoh'ols in the C to C range derived from coconut oil is an especially useful oleophilic component of the copolymer but the group of acrylic and alkacrylic esters of aliphatic alcohols of at least 8 carbons also are, in general, Well suited as the oleophilic component of the copolymer.

The basic amino nitrogen-containing component can be introduced through the use of appropriate copolymerizable monomers containing primary, secondary or tertiary amino nitrogen that is attached ultimately to the chain of the polymer as part of an extralinear substituent group in which the nitrogen is joined extranuclearly only to nonbenzenoid carbon atoms.

Such monomers as glycidyl acr'ylate or vinyl chloroacetate can be employed in the copolymerization. They introduce groups reactive toward ammonia or amines and thus provide a means of attaching the necessary basic amino groups to the polymer chain. Attachment of the amino groups to the main copolymer carbon chain can be through strictly hydrocarbon structures or through ether, ester, or amide linkages.

Particular examples of the basic amino-containing monomers include the basic amino substituted olefins such as p-(beta-diethylaminoethyl)styrene; basic nitrogencontaining heterocycles carrying a polymerizable ethylenically unsaturated substituent, such as the vin'yl pyridines and the vinyl alkyl pyridines, e. g. 2-vinyl-5-ethyl pyridine; esters of basic amino alcohols with unsaturated carboxylic acids such as the alkyl and cycloalkyl esters of the acrylic and alkacrylic acids, e.g., beta-methyl-aminoethyl acrylate, beta-diethylaminoethyl acrylate, 4-diethylamino-- cyclohex'yl methacrylate, and beta-beta-didodecylaminoethyl acrylate; unsaturated ethers of basic amino alcohols, such as the vinyl ethers of such alcohols, e.g., betaaminoethyl vinyl ether, and beta-diethylaminoethyl vinyl ether; amides of unsaturated carboxylic acids wherein a basic amino substituent is carried on the amide nitrogen such as N-(beta-dimethylaminoethyl)-acrylamide; and polymerizable unsaturated basic amines such as diallylamine. The term basic amino nitrogen is used generically herein to mean the primary, secondary and tertiary amines including, as stated above, the basic nitrogencontaining heterocycles.

Because of their relatively greater basicity and more effective sludge suspending and inhibiting properties, the polymerizable ethylenically unsaturated compounds containing a basic tertiary amino group are preferred and those having only primary basic amino groups are least desirable. Particularly outstanding and readily available basic amino nitrogen-containing components are the alkyl and cycloalkyl substituted tertiary aminoalkyl and cycloal-kyl esters of acrylic and alkacrylic acids.

The basic amino nitrogen-containing component of the copolymer must be present in a minor proportion by weight, corresponding to no more tha 3.5% and no less than 0.1% of basic amino nitrogen based on the weight of the polymer. Above the higher level, which, for example, corresponds to about 50% by weight of amino monomer in a lauryl methacrylate/beta-diethylaminoethyl methacrylate copolymer, and at less than the lower level, the performance of the polymer as a sludge inhibitor falls off rapidly. It is preferred that the basic amino nitrogen content be within the range of 0.2% to 3.0% by weight of the polymer.

The copolymers useful in the practice of the invention can be prepared by conventional bulk, solution, or dispersion polymerization methods involving known initiators, including oxygen-yielding compounds, such as benzoyl peroxide, and azo compounds, such as alpha, alpha-azodiisobutyronitrile. Convenient solvents are highboiling hydrocarbons, particularly those similar to the hydrocarbons in which the copolymers are to be used, such as kerosene. The polymerization process is usually carried out in an inert atmosphere such as nitrogen or carbon dioxide, at temperatures ranging from 30 C. to 150 C., depending on the catalyst used, and generally at temperatures between 50 C. and 70 C. when alpha, alpha'-azodiisobutyronitrile is used as the catalyst. It is important to carry the copolymerization substantially to completeness so that little or no unpolymerized monomer remains and the proportions of each component in the final product are essentially those of the original monomer mixture.

'(C) Amine neutralized acid phosphates-The third component of the compositions of this invention is an oilsoluble amine salt of an alkyl acid phosphate.

The acid alkyl phosphates are obtained by reacting an alcohol with phosphoric anhydride (P From about 2 to 4 moles of a primary alkanol or mixture of such alcohols may be employed per mole of P 0 Preferred for the present purpose are the approximately equimolar mixtures of the monoand dialkyl phosphates produced on using 3 moles of alcohol per mole of P 0 For the preparation of the acid alkyl phosphates, the alkanol is a primary alkanol, and preferably a branched primary alkanol, having 8 to 18 carbon atoms. Examples are the normal alkanols derived from coconut kernel oils. One such fraction, available commercially consists mainly of the n-octyl and n-decyl alcohol but contains other n-alkanols containing from 10 to 18 carbon atoms. Still another ranges from n-C to C with n-C predominating. Preferably the alcohol is a mixture of branched chain primary alkanols, such as those produced in the wellknown 0x0 process from C0, H and a branched chain olefin. Examples of these are the 0x0 octyl, decyl, tridecyl and octadecyl alcohols, all of which are mixtures consisting predominantly of branched chain primary alkanols obtained from propylene-butylene dimer, tripropyl ene, tetra-propylene and penta-propylene, respectively.

The amine salts of the subject compositions are oilsoluble substituted ammonium alkyl phosphates prepared by neutralizing an acid alkyl phosphate with a C to C monoamine. Most broadly, the amine can be a primary amine containing a tert-alkyl substituent on nitrogen, or a secondary or tertiary amine containing monovalent aliphatic, cycloaliphatic, or phenyl hydrocarbyl substituents on nitrogen, or a heterocyclic amine, such as pyridine.

Preferably, the amine will be a C to C tert-al'kyl primary amine, and most preferably the amine salt will be the salt of such an amine and the acid phosphate derived from the mixed octyl alcohols made by the 0x0 process. Examples of the tert-alkyl amines used to prepare these preferred additives are: 1,l,3,3-tetramethylbutyl amine (tert. octyl amine); the mixed tert, alkyl amine fractions having from 12 to 14 carbon atoms and from 18 to 21 carbon atoms, respectively, such as those marketed commercially under the trade names Primene 81- and Primene JM-T; and tert. nonyl amine, also available commercially, consisting mainly of the C with small amounts of C and C amines and having a molecular weight range of 143 to 157.

Representative of the secondary amines and tertiary amines are diisopropylamine; di 2 ethylhexylamine; N-octenylcyclohexylamine; triethylamine; tributylamine; triisoctylamine; N,N diethylcyclohexylamine; dimethyl aniline and pyridine.

The amine salts suitable for use in the compositions of this invention can be prepared simply by neutralizing the alkyl acid phosphate with an appropriate amine to a pH of about 6-7. The mixed acidic mono and dialkyl phosphates, and their amine salts described in the examples below were prepared by the following general procedures:

Anhydrous phosphoric pentoxide (P 0 was added gradually under anhydrous conditions to 3 molar equivalents of the alcohol under agitation. The addition of P 0 was regulated so as to maintain the reaction temperature in the range 40 to 90 C. Good results were ordinarily obtained either at 50:10" C. or at -l0 C. When the addition of P 0 was complete, the reaction mass was held at 60-70 C. for about 12 to 24 hours to complete the reaction. The course of the reaction can, if desired, be followed by conventional methods of analysis for reactants and products. In most instances, the acid alkyl phosphate was a viscous oil.

The amine salt was obtained by neutralizing the acid alkyl phosphate to a pH of about 7 by the addition thereto of approximately 2 moles of amine per mole of P 0 originally employed. Conveniently, the amine, together with sufficient kerosene to produce a final solution containing about 80% of the neutralized salt as the active ingredient, was added gradually to the acid phosphate under agitation, and the reaction mass held at 70J -10 C. until it became completely homogeneous.

(2) Preparation of the additive compositions The three components of the antistatic composition of this invention are mixed together in a liquid hydrocarbonmiscible solvent such as xylene, toluene, benzene, hexane or kerosene and preferably heated to facilitate formation of a homogeneous solution. They are mixed in such proportions that for one part by weight of the chromium phosphate there will be from /2 to 1 part of the nitrogen containing polymers and /2 to 16 parts of the amine neutralized alkyl phosphate. It is preferable that the amine phosphate be added before the polymer.

Since only very small amounts of the components of the composition are necessary to be effective in preventing the accumulation of static charge in the hydrocarbon liquid or fuel oil, they are conveniently added in the form of their solvent solution. This solvent concentrate ordinarily contains about 5090% by weight of the solvent. An amount of the solvent concentrate to be added to the liquid hydrocarbon is that which will incorporate therein about 1-6 p.p.m. of the chromium phosphate, /2--3 p.p.m. of the nitrogen containing polymer and /z-16 p.p.m. of

the amine phosphate. For practical purposes, these ranges correspond to approximately 0.3 to .2 pounds of the chromium phosphate, 0.15 to 1 lb. of the polymer and 0.15 to 4.5 lb. of the amine phosphate, per 1000 barrels of liquid hydrocarbon.

(3) Conductivity measurements The effectiveness of the compositions was tested in a Maihak Conductivity Meter. Solutions of the appropriate chromium triphosphate were prepared by dissolving 0.1896 gram of the chromium triphosphate, 0.0474 gram of the nitrogen containing polymer and 0.0948 gram of the amine neutralized alkyl phosphate in 25 milliliters of xylene and adding 0.1 milliliter of this solution to 1 liter of jet fuel or fuel oil and evaluating the conductivity of the resulting solution with the Maihak Conductivity Meter.

The Maihak Conductivity instrument is sold by H. Maihak A.G. Hamburg, Germany, for use in the measurement of the electrical conductivity of light oil products in ther anges of 0.500 and 0.1000 conductivity unit. A conductivity unit is equal to 1 10- mhoXmf =1 picomho m.- The instrument consists of a transmitter for immersion in the liquid to be checked and an indicator unit with cable reel. Both parts are connected via an oilresistant cable which is wound on the cable reel.

This instrument measures the resistance of the liquid between two electrodes of a transmitter cell. The resistance is determined by measuring the current flow when applying a measuring potential of 6 volts. This current is very low, a conductivity of 500 conductivity units (C.U.) corresponds to about 6.10- A., so it is amplified by means of an amplifier built inside the transmitter cell to a level that can be indicated on the Conductivity instrument.

The transmitter cell consists of chromium-plated brass electrodes. Both electrodes and cable connector are potted to one unit. The cell is immersed in the liquid to be measured and the liquid passes through holes below and above and circulates between the electrodes. After the transmitter has been immersed and has come to rest, the instrument is ready for measurements to be taken.

The power supply and measuring voltage to the transmitter are switched on. The reading taken is the maximum pointer deflection immediately after switching on the power.

EXAMPLE 1 To a reactor was added 239.4 grams of mixed monoand di-isooctyl phosphate. Then 500 milliliters of anhydrous isopropanol were added, the solution was stirred until homogeneous, and was heated to reflux (83 C.). Next, 36.0 grams of sodium hydroxide were dissolved in 36 grams of water and the resulting solution was added slowly to the monoand diisooctyl phosphate/isopropanol solution. The pH of the final solution was checked and found to be between 6-7. The solution was then heated to reflux (83 C.) and 79.8 grams of chromic chloride (CrCl -6H O) was added. After completion of addition, the solution was stirred at reflux for 1 hour. The by-product sodium chloride (wet with isopropanol and water) was removed by filtration. The remaining solution was then subjected to distillation followed by application of a 20-25 mm. vacuum while maintained at 8090 C. to remove all isopropanol and water. Two hundred and thirty four grams of chromium tri(monoand di-isooctyl) phosphate was recovered for a 93% yield.

EXAMPLE 2 To a reactor maintained with a nitrogen atmosphere was added 18.2 grams of triethyl phosphate followed by the slow addition of 14.2 grams of phosphorous pentoxide. The reaction solution was kept at 75-80 C. during the addition. After all of the phosphorous pentoxide was added, the reaction solution was held at 75-80" C. for an additional 2 hours. The solution was then cooled to 60 C. and 39.1 grams of Z-ethylhexanol were added and the reaction mass was stirred for about 20 hours at C. to obtain ethyl 2-ethylhexyl phosphate. The chr0- mium salt of the dialkyl phosphate was prepared as in Example 1. Sixty-one and three tenths grams of chromium tri-(ethyl-Z-ethylhexyl phosphate) were obtained for an 86% yield.

By following this same procedure, 59.4 grams of chromium tri-(ethyl, isooctylphosphate), (83% yield) and 61.6 grams of chromium tri-(ethyl, n-octylphosphate), (86.4% yield) were obtained.

EXAMPLE 3 To a reactor were added 100 milliliters of carbon tetrachloride and 30.64 grams of di-2-ethylhexyl phosphite. The solution was cooled to 0.5 C. and chlorine was bubbled through the solution at a moderate rate. After the solution became yellow in color (indicating an excess of chlorine) the introduction of chlorine was stopped and the solution stirred at 05 C. for /2 hour. The excess chlorine was then removed by purging the solution with nitrogen. The carbon tetra-chloride was then removed to give 34.2 grams of di-Z-ethylhexyl phosphorochloridate which was immediately converted into the di-2-ethylhexyl phosphate by the following procedure.

To a flask charged with 250 milliliters of water and 7.9 grams of pyridine was added dropwise 34.1 grams of di-Z-ethylhexyl phosphoro-chloridate while the solution was kept at about 30 C. After completion of the addition, the temperature of the solution was increased to C. and held for about 3 hours. The solution was then cooled and extracted with hexane and diethyl ether. The hexane/ether layers were dried with sodium sulfate. The hexane/ether was then removed to give 24.9 grams of di-Z-ethylhexyl phosphate, for a 77% yield.

EXAMPLE 4 To the 234.0 grams of chromium tri(monoand diisooctyl phosphate) obtained in Example 1, there was added 468 grams of kerosene. This heterogeneous solution was stirred at 80 C. for 1 hour while most of the chromium alkyl phosphate was dissolved. To this solution was added 117.0 grams of the Primene 81-R salt of mixed monoand diisooctyl acid phosphate, followed by stirring at 80 C. for /2 hour. 117.0 grams of a terpolymer consisting of octadecenyl methacrylate, styrene and fi-diethylaminoethyl methacrylate, 50/40/10, was then added and the resulting solution stirred at 80 C. for 1 hour. The final solution was allowed to cool and filtered to remove any undissolved material.

The initial conductivity tests are reported below in Table I and Table I-A.

TABLE L-CONDUO'IIVITY IN HYDROOARBON LIQUIDS Concentration, Conducp.p.m. in tivity J P-4 picomho Additive fuel a m.-

None 0-10 Chromium tri(di-Z-ethylhexylphosphate) 1 Primene 81-R 1 salt of monoand diisooctyl acid phosphate 12 10 Chromium tri(di-Z-ethylhexylphosphate) 1 Primene 81-12." salt of monoand diisooctyl acid phosphate 0. 5 Polymer A 0. 5 Chromium tri(monoand diisooctyl phosphate) 1 Primene 81-R salt of monoand diisooctyl acid phosphate V 0. 5 450i50 Polymer A 0.5 Primene 81-12 salt of monoand diisooctyl acid phosphate 12 Polymer A 12 40 Chroimum tri(methyl, isooctyl phosphate). 1 "Primene BI-R salt of monoand diisooctyl acid phosphate 0.5 Polymer A. 7 0. 5 300i50 Chromium tri(monoand diphenyl phosphate)- 1 Primene 81-R" salt of monoand diisooctyl acid phosphate 0.5 01 A 0.5 70:1;20

Primene 81-13. salt of monoand diisooctyl phosphate TABLE 1--'Continued Concentration, Conducp.p.m. in tivity J P-4 picomho Additive fuel 8 Xmr Polymer A 0. 5 50:l:20 Chromium t ri(monoand diisooctyl phosphate). 1 n-Propylamine salt of monoand diisooctyl phosphate 0. 4 Polymer A 0. 5 280 Chromium tri(monoand diisooctyl phosphate). 1 Ethanolamme salt of monoand diisooctyl phosphate 0. 4 Polymer A 0. 5 500 Chromium tri (monoand diisooctyl phosphate). 1 Dimethylcyclohexylamine salt of monoand diisooctyl phosphate Polymer A Chromium tri(monoand diisooctyl phosp e) Di-Z-ethylhexylamine salt of monoand diisooctyl phosphate Polymer A Chromium tri(monoand diisooctyl phosphate). n-Decylamine salt of monoand diisooctyl Polymer A Chromium tri(monoand diisooctyl phosphate). Aniline salt of monoand diisooctyl phosphate.. Polymer A Chromium tri(monoand diisooctyl phosphate). 2-Ethylhexylamine salt of monoand ditridecylphosphate Polymer A Chromium tri(monoand diisooctyl phosphate). "Primene 8l-R salt of monoand diisooctyl TABLE IL-WATER WASH TEST Conductivity picomho m.-

Before After wash wash Concentration p.p.m. in Additive JP-4 fuel Chromium tri(mon0- and diisooctyl phosphate) "Primene 81-11" salt of m phosphate). Primene 81R" salt of isooctyl phosphate. Polymer C Chromium tri(monoand diisooctyl phosphate) Polymer C phos hate 16 Polym r A 0. 5 500400 TABLE III Chromium tri(monoand diisooctyl phosphate). 1 Primene 81-12." salt of monoand diisooctyl Amine of 1110110 and diisooctyl phosphate 1 Phosphate (rggly'mer A. ".n n u nn n i 450-550 ggzf g W ight G 1 romium tri monoan 'isooc y p osp ate e e a- Primene 81-R salt of monoand diisooctyl 801mm Percent Amine Percent fi m Iihosp 1;? "B116 1 85 Ye s. P0 ymer u 2 81 Primene 81-R 4 N l Primene 81R is a mixture of tertiary alkyl amines containing from 12 3 31 Z HiNH 4 No. to 14 carbon atoms. 4 81 Triethylamme 4 No. 2 PolymerAis 50/40/10 wt. percent octadecenyl methacrylate/styrene/B- 5 31 i y ye ohexy emi 4 No. diethylaminoethyl methacrylate. 5 81 Y Y e-- 4 No. 8 J P-4 fuel had the following inspection data: APT gravity, 46; Aro- 31 e y e 4 No. matic max., 25 volume percent; Olefin content, 5 volume percent; Boiling 81 yp 4 No. range, 50% at 370 F., 90% at 470 F. 81 Amlme 4 No. 4 Polymer B is 95/5 wt. percent 2-ethylhexyl acrylate/diethylamino- 10 81 y y mme Sell; 4 No. ethyl vinyl ether. m0n0- and d1tndecyl phosphate.

TABLE I-A Conductivity, average picomhoXm.-

Concen- I In tration, In fuel In fuel rubber In mineral Additive p.p.m. 011 D oil E solvent I heptane spirits 1 Chromium tri(monoand diisooctyl phosphate). 1 "Primene 81-R salt of monoand diisooctyl phosphate. 0. 5 Polymer A 0. 5 90=i=10 120=|=10 -1,o00 350530 525g Chromium tri (monoand diisooctyl phosphate)- 6 "Primene 8l-R salt of monoand diisooctyl phosphate-.. 3 Polymer A 3 470=l=20 600=|=20 1 Commercially available No. 2 fuel oil.

2 Petroleum distillate used in making rubber cements and in tire manufacture, volatility similar to gasoline (boiling range 150-3 F) In order to demonstrate the ability of the additive compositions of the invention to remain in the oil phase, they were subjected to a stringent wash test described below.

Effect of washing with water Procedure-To one liter of JP-4 jet fuel was added ,ul of a stock solution containing one of the antistatic additive compositions in kerosene or xylene. This resulted in the Chromium tri (alkyl phosphate) being added at 1 p.p.m. to the jet fuel, the amine phosphate and nitrogen containing polymer being present at /2 p.p.m. The conductivity of the resulting solution was then measured after the solution had been stored for several days in metal cans so that an equilibrated value could be obtained.

The one liter jet fuel solution was then thoroughly mixed with 100 ml. of water for 5 minutes. The water was then allowed to separateand was removed. The conductivity of the jet fuel solution was then determined again with the Maihak Conductivity Meter.

00 i Petroleum distillate used as thinner in paints and varnishes with a boiling range of 200-300 F.

What is claimed is: 1. A composition for increasing the conductivity of hydrocarbon liquids consisting essentially of (1) one part by weight of a trivalent chromium salt of (a) an alkyl phosphate, said salt having the formula wherein R and R can be the same or different, and

R is alkyl of 1 to 16 carbon atoms, alkylphenyl wherein the alkyl contains 1 to 16 carbon atoms, or phenyl, and R is alkyl of 3 to 16 carbon atoms, alkylphenyl wherein the alkyl contains 1 to 16 carbon atoms, or phenyl; or

1 1 (b) a mixture of (i) 60 to 40 mol percent of a monohydrocarbon dihydrogen phosphate, and (ii) 40 to 60 mol percent of a dihydrocarbon monohydrogen phosphate, wherein the hydrocarbon is alkyl of 4 to 16 carbon atoms, alkylphenyl wherein the alkyl contains 1 to 16 carbon atoms, or phenyl (2) from .5 to 1 part by weight of an oil soluble copolymer wherein (a) from about 50 to about 95% by weight of the polymer is units from a long-chain ester of an unsaturated carboxylic acid which contains from 8 to 18 carbon atoms in an aliphatic hydrocarbon chain which is not part of the polymer chain; (b) from about to about 10% by weight of the polymer is units from unsaturated ethers of basic amino alcohol, or esters of basic amino alcohols with unsaturated carboxylic acids, wherein the basic amino nitrogen is not itself part of the polymer chain; (c) from 0 to about 45% by weight of the polymer is units from styrene; and (d) each of the monomers, prior to polymerization, contains a carbon-carbon double bond capable of participation in free radical initiated addition copolymerization; said copolymer having an inherent viscosity of between 0.1 and 3.0 at 1% weight-volume concentration in benzene at 25 C. and containing from 0.1 to 3.5 weight percent of basic amino nitrogen; and (3) from .5 to 16 parts by weight of an oil soluble salt of (a) a 2 to 24 carbon atom monoamine selected from among (i) tertiary alkyl primary amines; (ii) secondary amines having 2 monovalent 12 saturated hydrocarbon radical substituents; and (iii) tertiary amines having 3 monovalent saturated hydrocarbon radical substituents; and (b) mixed monoalkyl acid phosphates and dialkyl acid phosphates wherein the alkyl groups contain 8 to 18 carbon atoms.

2. A composition of claim 1 wherein the oil soluble salt (3) is the salt of an 8 to 21 carbon tertiary alkyl primary amine, and an acid phosphate in which the alkyl groups are branched chain primary alkyl groups.

3. A solution of a composition of claim 1 in a hydrocarbon-miscible solvent, said solution containing about to percent 'by weight of said solvent and about 10 to 40 percent by weight of the composition of claim 1.

4. A liquid hydrocarbon composition comprising a major portion of a liquid hydrocarbon and an amount suflicient to increase the conductivity of said liquid hydrocarbon of a composition of claim 1.

References Cited UNITED STATES PATENTS 3,126,260 3/ 1964 Van der Minne 4462 3,210,169 10/1965 Van der Minne 44-'-62 3,336,124 8/1967 Dunworth 4462 3,012,969 12/1961 Van der Minne 4470 3,084,035 4/1963 Rogers et a1. 44-68 3,397,971 8/1968 Van der Minne 4468 3,013,868 12/1961 Skei et a1. 44-62 2,888,340 5/1959 Winnick 4462 DANIEL E. WYMAN, Primary Examiner Y. H. SMITH, Assistant Examiner US. Cl. X.R. 4468, 72, Dig. 4