US3674450A - Antistatic additive for hydrocarbon fuels - Google Patents

Abstract

AN ANTISATATIC ADDITIVE FOR HYDROCARBON FUELS COMPRISING A SYNERGISTIC MIXTURE OF (A) A HYDROCARBYL ACID PHOSPHATE SALT OF A POLYAMIDE HAVING AT LEAST ONE AMINO GROUP AND (B) METAL SALTS OF A MIXTURE OF A NAPHTHENIC ACID AND AN ALKANOIC ACID WHEREIN THE METAL IS A MIXTURE OF A GROUP IIA METAL AND A TRANSITION METAL SELECTED FROM THE GROUP CONSISTING OF IRON, COBALT, NICKEL, COPPER, AND ZINC AND, PREFERABLY, A MONOHYDROCARBYL ETHER OF A GLYCOL; AND HYDROCARBON FUEL COMPOSITIONS CONTAINING SAID ANTISTATIC ADDITIVE. THE HYDROCARBON FUEL COMPOSITIONS OF THIS INVENTION COMPRISE A MAJOR PROPORTION OF THE HYDROCARBON FUEL AND A MINOR PROPORTION OF THE ANTISTATIC ADDITIVE. THE PREFERRED HYDROCARBON FUELS ARE DISTILLATE FUELS SUCH AS NO. 1 FUEL, NO. 2 FUEL, DIESEL FUEL, AND TURBINE FUEL.

Description

United States Patent 3,674,450 ANTISTATIC ADDITIVEIFSOR HYDROCARBON Int. Cl. C] N26 US. Cl. 44-66 12 Claims ABSTRACT OF THE DISCLOSURE An antistatic additive for hydrocarbon fuels comprising a synergistic mixture of (a) a hydrocarbyl acid phosphate salt of a polyamide having at least one amino group and (b) metal salts of a mixture of a naphthenic acid and an alkanoic acid wherein the metal is a mixture of a Group Ha metal and a transition metal selected from the group consisting of iron, cobalt, nickel, copper, and Zinc and, preferably, a monohydrocarbyl ether of a glycol; and hydrocarbon fuel compositions containing said antistatic additive. The hydrocarbon fuel compositions of this invention comprise a major proportion of the hydrocarbon fuel and a minor proportion of the antistatic additive. The preferred hydrocarbon fuels are distillate fuels such as No. 1 fuel, No. 2 fuel, diesel fuel, and turbine fuel.

BACKGROUND OF THE INVENTION Normally liquid hydrocarbon fuels often require additives to improve their performance characteristics. For example, the petroleum industry has encountered problems in supplying middle distillate and heavy residual oils suitable for use in oil burners and compression ignition and turbine engines which will not contribute materially to the pollution of the atmosphere through soot and smoke production. In addition, in motor fuels such as gasoline, diesel fuel, and jet fuel, various additives are employed to assist in maintaining cleanliness in the carburetor and fuel intact system, to prevent carburetor icing, to inhibit rust, and to reduce the amount of unburned hydrocarbons in the engine exhaust. However, common to all normally liquid hydrocarbon fuels is the need to dissipate static electricity. Fuel handling operations, such as pumping from storage tanks to trucks or aircraft, can build up a static charge that, if not dissipated, can cause fires and explosions.

Prior art fuel additives vary in effectiveness, and it is often necessary to use a number of additives in a single fuel composition. Many additives for hydrocarbon fuels are only marginally soluble in hydrocarbons. Furthermore, they are often employed in concentrations that ap proach their limits of solubility. As a result, hydrocarbon compositions containing such additives often exhibit poor stability and, as a result, on standing the additive may precipitate.

In addition, many additives for hydrocarbon fuels have poor water tolerance. When fuel compositions containing such additives come in contact with water as, for example, in storage tanks, water enters the hydrocarbon phase. This is particularly deleterious in jet fuels. The temperatures at high altitudes where jet aircraft operate are well below freezing. Hence, water in the fuel crystallizes and plugs fuel filters, thereby cutting off the flow of fuel to the engines. To combat this, fuel tank heaters and additives to prevent ice formation are employed.

O-ther typical deficiencies of prior art hydrocarbon fuel additives include thermal instability and poor oxidative stability.

Accordingly, these exists a need for hydrocarbon fuel compositions having good electrical conductivity and 3,674,450 Patented July 4, 1972 which are, in addition, free of the undesirable side effects and deficiencies of prior art hydrocarbon fuel compositions.

SUMMARY OF THE INVENTION It is an object of this invention to provide an antistatic additive for normally liquid hydrocarbon fuels.

It is another object of this invention to provide an antistatic additive for normally liquid hydrocarbon fuels that has excellent water tolerance.

It is yet another object of this invention to provide an antistatic additive for normally liquid hydrocarbon fuels that has such desirable properties as oxidative and thermal stabilities.

Still another object of this invention is to provide a normally liquid hydrocarbon fuel composition having excellent electrical conductivity properties.

Yet another object of this invention is to provide a normally liquid hydrocarbon fuel composition having excellent electrical conductivity properties which also exhibits such desirable properties as reduced unburned hydrocarbons in the exhaust Still other objects and advantages of this invention will be evident to those skilled in the art in view of tlns disclosure.

The foregoing objects are achieved in accordance with this invention. In general, this invention consists of an antistatic additive for normally liquid hydrocarbon fuels comprising:

(a) a hydrocarbyl hydrogen phosphate salt of a compound having the general formula wherein m is at least 1 and the sum of n plus m is from 2 to about 6, R is a multivalent hydrocarbon group of about 2 to about 50 carbons, R is a hydrocarbylene group of about 2 to about 12 carbons, R is selected from the group consisting of hydrogen and hydrocarbyl groups of about 1 to about 30 carbons, R' is a hydrocarbyl group of from about 2 to about 12 carbons, and at least 10% of the amino groups contained therein are converted to the hydrocarbyl hydrogen phosphate salt; and

(b) metal salts of a naphthenic acid plus an alkanoic acid wherein the metal is a mixture of a Group He. metal and a transition metal selected from the group consisting of iron, cobalt, nickel, copper, and zinc; and a normally liquid hydrocarbon fuel composition comprising a major proportion of a normally liquid hydrocarbon fuel and a minor proportion of the additive of this invention.

By using the additives of this invention it is possible to prepare normally liquid hydrocarbon fuel compositions which have excellent electrical conductivity properties and which, in addition, are characterized by reduced unburned hydrocarbons in the exhaust gases of engines operated thereon. Furthermore, the hydrocarbon fuel compositions exhibit such desirable properties as superior water tolerance, carburetor detergency, corrosion inhibition, good carburetor anti-icing characteristics, thermal stability, oxidative stability, and little if any tendency to form a precipitate on standing.

DESCRIPTION OF THE PREFERRED EMBODIMENTS This invention is concerned with antistatic additives for normally liquid hydrocarbon fuels and normally liquid hydrocarbon fuel compositions containing said additives. The additives of this invention impart excellent electrical conductivity properties to hydrocarbon fuels while at the same time yielding a hydrocarbon fuel composition characterized by reduced unburned hydrocarbons in the exhaust gases of engines operated thereon. The hydrocarbon fuel compositions of this invention additionally exhibit desirable properties such as superior water tolerance, carburetor detergency, corrosion inhibition, good carburetor anti-icing characteristics, thermal stability, oxidative stability, and little if any tendency to form a precipitate on standing.

The antistatic additive of this invention is a synergistic mixture of two main components, each of which has antistatic properties. The two main components of the instant antistatic additive are (a) a hydrocarbyl acid phosphate salt of a polyamide having at least one amino group and (b) metal salts of a mixture of a naphthenic acid and an alkanoic acid wherein the metal is a mixture of a Group IIa metal and a transition metal selected from the group consisting of iron, cobalt, nickel, copper, and zinc and, preferably, a monohydrocarbyl ether of a glycol.

Component (a) of the antistatic additive is prepared by reacting a hydrocarbyl hydrogen phosphate with a polyamide containing from 2 to about 6 amide groups and at least one amino group whereby at least about 10% of the amino groups are converted to the hydrocarbyl hydrogen phosphate salt. The polyamides are prepared by condensing a polycarboxylic acid having from 2 to about 6 carboxyl groups with an amine or amines to convert each carboxyl group to the corresponding N-substituted amide group. It is critical that at least one N-substituted amide group in every molecule contain an amino group on the substitutent. Thus at least one carboxyl group of the polycarboxylic acid must be condensed with a polyamine, preferably a diamine, while the remainder of the carboxyl groups may be condensed with either a monoamine or a polyamine. However, it is preferred that each carboxyl group be condensed with a diamine. The preferred acids are dicarboxylic acids. Hence the preferred polyamides are diamino-diamides having the general formula I if g I I H wherein R is a hydrocarbylene group of about 2 to about 52 carbons and preferably about 4 to about 34 carbons, R is a hydrocarbylene group of about 2 to about 12 carbons and preferably about 2 to about 6 carbons, and R" is selected from the group consisting of hydrogen and hydrocarbyl groups of about 1 to about carbons and prefer ably about 3 to about 24 carbons.

The hydrocarbyl hydrogen phosphate which is reacted with the polyamide containing one or more amino groups to form the salt is preferably a hydrocarbyl hydrogen orthophosphate. The hydrocarbyl hydrogen orthophos phate may be a dihydrocarbyl hydrogen orthophosphate, a hydrocarbyl dihydrogen orthophosphate, or preferably a mixture of a dihydrocarbyl hydrogen orthophosphate and a hydrocarbyl dihydrogen orthophosphate. The hydrocarbyl portions contain from about 1 to about 15 carbons and preferably from about 3 to about 10 carbons. In the case of dihydrocarbyl hydrogen orthophosphates and mixtures of dihydrocarbyl hydrogen orthophosphates and hydrocarbyl dihydrogen orthophosphates, the hydrocarbyl groups may be the same or different. The hydrocarbyl portions may be aliphatic, aromatic, or naphthenic or they may contain various mixtures of aliphatic, aromatic and naphthenic segments. Aliphatic and naphthenic segments may be either saturated or unsaturated. The ratio of hydrocarbyl hydrogen orthophosphate to the polyamide containing one or more amino groups is such that at least about 10% of the amino groups are converted to the hydrocarbyl hydrogen orthophosphate salt. While about 10% to about 100% of the amino groups may be converted to the hydrocarbyl hydrogen orthophosphate salt, it is preferred that about 50% to about 90% of the amino groups be converted to the salt since the presence of some free amino groups is usually desirable. However, an excess of hydrocarbyl hydrogen orthophosphate may be present in the case where 100% of the amino groups are converted to the salt.

As stated above, the polyamide containing from 2 to about 6 amide groups and at least one amino group has the general formula wherein -R is a multivalent hydrocarbon group of about 2 to about 52, and preferably about 4 to about 34, carbons, and m is at least 1 and the sum of it plus m is from 2 to about 6. The polycarboxylic acid from which the polyamide is made therefore has the general formula wherein R is a multivalent hydrocarbon group of about 2 to about 52 carbons and preferably about 4 to about 34 carbons. R may be aliphatic, aromatic, or naphthenic, or it may contain various mixtures of aliphatic, aromatic, and naphthenic segments. Aliphatic and naphthenic segments may be either saturated or unsaturated. While the sum of m plus it may be from 2 to about 6, it is preferred that the sum of m plus it be 2, i.e., a dicarboxylic acid. Examples of suitable polycarboxylic acids are succinic acid; glutaric acid; adipic acid; terephthalic acid; 1,4- cyclohexanedicarboxylic acid; pyromellitic acid; 1,18-dicarboxyoctadecane; and trimer acid which is the trimer of a polyunsaturated C monocarboxylie fatty acid, being a C tricarboxylic acid of uncertain structure. The preferred polycarboxylic acid is a dimer acid produced by the dimerization of a polyunsaturated C monocarboxylic fatty acid to produce an unsaturated C dicarboxylic acid whose exact structure is not known with certainty. Such a dimer acid is produced by General Mills under the tradename of Versadyme 216.

The amine which is condensed with the polycarboxylic acid to form the polyamide is selected from the group consisting of monoamines and polyamines, preferably diamines, having the general formulas phatic, naphthenic and aromatic segments. Aliphatic and naphthenic segments may be either saturated or unsaturated. Examples of suitable monoamines are diethylamine, dodecylamine, cyclohexylarnine, methylbutylamine and propylamine. Examples of suitable diamines are ethylenediarnine;

propylenediamine;

1,12-diaminododecane; hexamethylenediamine; N-methyl-N'-propyl-1 ,3-propylenediamine; N,N-dibutylethylenediamine 1,4-diaminohexane; N-oleyl-l,3-propylenediamine; N-cyclohexylethylenediamine; and

N- lil-phenylste aryl) -1,3 -propylenediamine.

The preferred amine is N-tallowyl-l,3-propylenediamine.

Examples of hydrocarbyl hydrogen phosphates are triethyl hydrogen pyrophosphate, methylphenyl dihydrogen pyrophosphate, cyclohexyl dihydrogen orthophosphate, di-

phenyl hydrogen orthophosphate, methyldecyl hydrogen orthophosphate, pentadecyl dihydrogen orthophosphate, dipropyl hydrogen orthophosphate, heptyl dihydrogenorthophosphate, isooctyl dihydrogen orthophosphate, and diisooctyl hydrogen orthophosphate. The preferred hydrocarbyl hydrogen phosphate is a mixture of isooctyl dihydrogen orthophosphate and diisooctyl hydrogen orthophosphate.

In order that this component of our additive have the necessary solubility in hydrocarbon fuels, it is necessary that the polyamide containing from 2 to about 6 amide groups and at least 1 amino group contain about 24 to about 100, and preferably about 30 to about 90, carbons. Since the preferred acid for amide formation is dimer acid, the preferred amine is N-tallowyl-1,3-propylenediamine, and the preferred hydrocarbyl hydrogen phosphate for salt formation is a mixture of isooctyl dihydrogen orthophosphate and diisooctyl hydrogen orthophosphate, the preferred component is a mixture of isooctyl dihydrogen orthophosphate and diisooctyl hydrogen orthophosphate salts of the diamide obtained by condensing one mole of dimer acid with 2 moles of N-ta1lowyl-1,3-propylenediamine. It will be understood that when the dimer acid condenses with the diamine to form the diamino-diamide, either amino group may condense with a carboxyl group and the product is therefore a mixture of the following isomers wherein R is the C hydrocarbylene portion of the dimer acid and R' is a tallowyl group. The ratio of the mixture of isooctyl hydrogen orthophosphates to the diaminodiamide to form the preferred component is such as to convert from about to about 100%, and preferably about 50% to about 90%, of the amino groups of the diaminodiamide to the corresponding isooctyl hydrogen orthophosphate salts. In the case where 100% of the amino groups are converted to the salt, it is contemplated that an excess of the mixture of isooctyl hydrogen orthophosphates may be present.

A particularly advantageous method of handling this component of the additive is to form a cocktail of the component with other ingredients which, for example, enhance the ease of solution of the component in the fuel and the handling characteristics of the component itself. An especially desirable cocktail contains 45 wt. percent of the preferred component (a) of the additive, the component being prepared by reacting about 3 parts of weight of the condensation product of 1 mole of dimer acid and 2 moles of N-tallowyl-l,3-propylenediamine with about 1 part by Weight of a mixture of about 65 wt. percent diisooctyl hydrogen orthophosphate and about 35 wt. percent of isooctyl dihydrogen orthophosphate. Thus about 80-90% of the amino groups of the diamino diamide are neutralized by the mixture of isooctyl hydrogen orthophosphates. The remainder of the cocktail comprises 48.6 wt. percent toluene, 4.5 wt. percent methanol, and 1.9 wt. percent of a demulsifying agent, advantageously DS-415 manufactured by Petrolite Corporation.

Component (b) of the antistatic additive of this invention comprises metal salts of a naphthenic acid plus an alkanoic acid wherein the metal is a mixture of a Group IIa metal and a transition metal selected from the group consisting of iron, cobalt, nickel, copper, and zinc. The preferred component (b) of the additive of this invention comprises the foregoing mixture of acid salts plus the monohydrocarbyl ether of a glycol.

The naphthenic acids which find utility in the practice of this invention are usually saturated and are commonly derived from petroleum sources. Generally, one or more alkyl groups are attached to the cycloparaffinic portion of the molecule. Naphthenic acids derived from petroleum sources are usually mixtures and their nature and properties are well known to those skilled in the art. The naphthenic acids that are useful in the practice of this invention may advantageously contain about 10 to 30 carbons. Naphthenic acids containing about 16 to 24 carbons are preferred. While the naphthenic acid may be a discreet compound, there are economic advantages to using mixtures of naphthenic acids. Thus it is especially preferred that a mixture of naphthenic acids derived from petroleum sources and containing about 16 to 24 carbons and having an average carbon content of about 20 be employed in this invention.

The alkanoic acids which may be employed in the practice of this invention are saturated. The alkanoic acids may contain about 4 to 12 carbons, and preferably about 6 to 10 carbons. It is particularly preferred that the alkanoic acid contain branching in the alpha-position. Examples of suitable alkanoic acids are butyric acid; valeric acid; hexanoic acid; octanoic acid; decanoic acid; undecanoic acid; dodecanoic acid; 2,2-dimethyldecanoic acid; Z-methyloctanoic acid; 3-ethylhexanoic acid; 2-ethylheptanoic acid; 2-propylvaleric acid; isovaleric acid; and mixtures thereof. The preferred acid is Z-ethylhexanoic acid.

The metals employed to convert the mixture of naphthenic acid and alkanoic acid to the metal salts are a mixture of a Group ID: metal and a transition metal selected from the group consisting of iron, cobalt, nickel, copper, and Zinc. The preferred Group IIa metals are calcium and barium while the preferred transition metals are copper and zinc. The most preferred metals are a mixture of barium and zinc.

The preferred component (b) of the antistatic additive contains, in addition to the metal salts of the naphthenic and alkanoic acids, at monohydrocarbyl ether of an alkylene glycol, preferably a 1,2-glycol. Generally, the monohydrocarbyl ether of an alkylene glycol will contain about 3 to 30 carbons, and preferably about 4 to 18 carbons. Examples of suitable ethers are the monomethyl ether of ethylene glycol, the monomethyl ether of propylene glycol, the monohexyl ether of trimethylene glycol, the monophenyl ether of diethylene glycol, the monocyclohexyl ether of pentaethylene glycol, the monoamyl ether of tripropylene glycol, and the monobutyl ether of hexamethylene glycol. The preferred ether is the monobutyl ether of ethylene glycol.

The metal salts of the naphthenic acid and the alkanoic acid may be prepared by reacting the corresponding acid with a suitable basic compound of the appropriate metal. Examples of suitable classes of basic metal compounds are the oxides, the hydroxides, and the carbonates of the metals. The naphthenic acid and the alkanoic acid may be reacted separately with the basic Group IIa metal compound and the basic transition metal compound and the metal salts thus formed mixed in the desired proportions. However, it is preferred to prepare a mixture of the naphthenic acid and the alkanoic acid in the desired ratio and react the mixture with the stoichiometric amount of a mixture in the desired ratio of basic compounds of the Group IIa metal and the transition metal.

The mole ratio of the naphthenic acid to the alkanoic acid is broadly from about 15:1 to 1:15. The preferred mole ratio of naphthenic acid to alkanoic acid is from about 6:1 to 1:2. It has been found that when the naphthenic acid is a mixture of acids containing about 16 to 24 carbons and having an average carbon content of about 20, and the alkanoic acid is Z-ethylhexanoic acid, it is especially preferred that the mole ratio of naphthenic acid to alkanoic acid be from about :1 to about 3:1.

The naphthenic acid and alkanoic acid are converted to the metal salts by reaction with basic compounds of the Group IIa metal and the transition metal. The molar ratio of Group Ila metal to transition metal, expressed as the metal, is broadly from about 3.521 to 8:1 and preferably from about 4:1 to 6:1. When the Group Ila metal is barium and the transition metal is zinc, it has been found that a particularly preferred molar ratio, expressed as the metal, is from about 4.5:1 to about 5.5: 1.

Accordingly, component (b) of the additive may be prepared by first mixing the naphthenic acid and the alkanoic acid in a molar ratio of about 15:1 to about 1:15, and preferably about 6:1 to about 2:1, naphthenic acid to alkanoic acid. To the mixture of acids is added the stoichiometric amount of a mixture of basic compounds of a Group Ila metal and a transition metal selected from the group consisting of iron, cobalt, nickel, copper, and zinc in a ratio such that the mole ratio of the Group Ila metal to the transition metal, expressed as the metal, is from about 3.5 :1 to about 8:1, and preferably from about 4:1 to about 6:1.

The preferred component (b) of the antistatic additive of this invention contains, in addition to the mixed metal salts of the mixture of naphthenic and alkanoic acids, a monohydrocarbyl ether of a glycol. The amount of ether in the component may broadly be about 1 to 6 wt. percent, and preferably about 2 to 5 wt. percent, based on the total component. When the ether is the monobutyl ether of ethylene glycol, the component advantageously contains about 4 wt. percent, based on the total component, of the ether.

In addition to the mixed metal salts of the mixture of naphthenic and alkanoic acids, and ether when it is present, a small amount of a diluent may also be present. For example, a hydrocarbon such as toluene may be present in minor quantities. The presence or absence of a diluent is not critical and the amount, if a diluent is present, is empirical and within the capability of one skilled in the art to determine. It is advantageous to have present in the component about 1 to 10 wt. percent, and preferably about 3 to 7 wt. percent, of a hydrocarbon diluent wherein the wt. percent is based on the component (b) plus diluent.

In some circumstances it is advantageous to prepare a concentrate of component (b) in a suitable hydrocarbon fuel such as, for example, diesel fuel, jet fuel, No. 2 fuel oil, or kerosene. One readily apparent advantage of a concentrate of the component in a hydrocarbon fuel is case of solubility in the ultimate hydrocarbon fuel. The quantity of the hydrocarbon fuel in the concentrate of the component is not critical and may readily be varied by one skilled in the art to suit the particular circumstances. It has been found advantageous to form concentrates of the component containing about to about 70% by weight, based on the total concentrate, of hydrocarbon fuel. Component (b) concentrates containing about 25% to about 50% by weight of hydrocarbon fuel, based on the total concentrate, are preferred. Especially preferred are concentrates containing about 33 wt. percent, based on the total concentrate, of kerosene.

The antistatic additive of this invention comprises a mixture of component (a) and component (b) in a weight ratio within the range of from about 28:1 to about 1:15 component (b) to component (a). The preferred weight ratio is within the range of from about :1 to about 1:2 component (b) to component (a). In the case of the most preferred antistatic additive where component (a) of the additive is the reaction product of about 3 parts by weight of the condensation product of one mole of dimer acid and two moles of N-tallowyl-l,3-propylenediamine with about 1 part by weight of a mixture of about 65 Wt. percent diisooctyl hydrogen orthophosphate and about 35 vwt. percent of isooctyl dihydrogen orthophosphate and component (b) of the additive is the mixed barium and zinc salts of a mixture of naphthenic acids containing about 16 to 24 carbons and Z-ethyl-hexanoic acid plus the monobutyl ether of ethylene glycol, the most preferred weight ratio of component (b) to component (a) is within the range of from about 15 :1 to about 1:1.

Hydrocarbon fuel compositions of this invention broad 1y comprise a major proportion of a hydrocarbon fuel and a minor proportion of the inventive antistatic additive. Generally, it has been found that hydrocarbon fuel compositions containing from about 1 to about lbs. of additive per thousand barrels (PTB) of the composition are used. However, hydrocarbon fuel compositions containing from about 3 to about 50 PTB of additive are preferred. In the case of hydrocarbon fuel compositions containing the most preferred antistatic additive described above, it is especially preferred that the hydrocarbon fuel be a distillate fuel such as No. 1 fuel, No. 2 fuel, diesel fuel, or turbine fuel and that the hydrocarbon fuel composition contain from about 3 to about 25 PTB of said most preferred additive.

When the hydrocarbon fuel composition of this invention is prepared from a cocktail of the antistatic additive derived from a cocktail of component (a) and a concentrate of component (b) in a hydrocarbon fuel, the amount of the cocktail" of additive used will depend on the concentration of the active ingredients of the additive therein. In the case Where the additive cocktail is prepared from a cocktail containing about 45 Wt. percent of component (a) and a concentrate containing about 64 weight percent of component (b), the preferred hydrocarbon fuel composition contains about 5-55 PTB of said additive cocktai The invention will be further illustrated by the following specific examples.

EXAMPLE I A number of antistatic additive cocktails are prepared by mixing various proportions of a cocktail of component (a) with a concentrate of component (b). The cocktail of component (a) comprises 48.6 wt. percent toluene; 4.5 wt. percent methanol; 1.9 wt. percent of DS-415, a demulsifying agent manufactured :by Petrolite Corp.; and 45 wt. percent of component (a), said component being the reaction product of about 3 parts by weight of the condensation product of one mol of dimer acid and two moles of N-tallowyl-1,3-propylenediamine with about 1 part by Weight of a mixture of about 65 wt. percent diisooctyl hydrogen orthophosphate and about 35 wt. percent of isooctyl dihydrogen orthophosphate. The concentrate of component (b) comprises 4.3 parts by weight of toluene; 50.6 parts by weight of kerosene; and 97.0 parts by weight of component (b). Thus the concentrate is 63.9 wt. percent of component (b). Component (b) comprises 4.4 wt. percent of the monobutyl ether of ethylene glycol and 95.6 wt. percent of mixed barium and Zinc salts of a mixture of naphthenic acids containing about 16 to 24 carbons and having an average carbon content of about 20 plus 2ethylhexanoic acid wherein the mole ratio of barium to zinc, as the metal, is about 5:1 and the mole ratio of naphthenates to 2-ethylhexanoate is about 4: 1.

The additive cocktails, comprising 20 PTB of tures of the cocktail of component (a) and the concentrate of component (b) in various proportions, are incorporated in both a No. 1 fuel oil and a No. 2 fuel oil and the conductivities of the resulting fuel compositions are determined. In Table I are shown the make-up of the antistatic additives, their concentrations in the fuel oil compositions, and the conductivities in picomhos/ meter of the fuel oil compositions.

TABLE I CocktalP' Concentrate Antlstatie Weight Conductivity, containing cont g additive, PTB Ratio, picomhos/rneter 45 wt. percent 63.9 wt. per- [Component Component Component (a), cent Compo- Component Component (a) plus Com- (b):Com- N o. 1 No. 2 PTB nent PTB PTB (b PTB ponent (11)] ponent (a) fuel fuel 1 4 20 0 12. 78 12. 78 182 202 19 0. 45 12. 14 12. 59 26. 98:1 340 240 5 15 2. 25 9. 58 ll. 83 4. 26:1 418 306 4. 5O 6. 39 10. 89 1. 42:1 375 294 5 6. 75 3. 19 9. 94 1:2. 12 100 149 1 8. 55 0. 64 9. l9 1: 13. 36 16 37 0 9. 00 0 9. 00 16 26 The data in Table I illustrate the synergistic interaction of components (a) and (b). While component (a) and component (b) individually impart antistatic properties to the fuel oil compositions, it is apparent that mixtures of component (a) and component (b) are more effective as antistatic additives than is either component alone. It is seen that as component (b) is partially replaced by component (a), the conductivity increases to a maximum at a weight ratio of component (b) to component (a) of about 4.26:1 and the mixture is still more effective than either component alone at a Weight ratio of component (b) to component (a) of about 1.42:1, even though the overall amount of antistatic additive is decreasing. :After passing through a maximum, the conductivity drops oif as the additive approaches pure component (a).

The fuel oil compositions will also exhibit such desirable propern'es as thermal and oxidative stabilities and good water tolerance.

EXANIPLE II A number of antistatic additive cocktails are prepared by mixing various proportions of the cocktail of component (a) described in Example I with the concentrate of component (b) described in Example I. Each additive cocktail contains various proportions of components (a) and (b), but the overall concentration of antistatic additive in each case is the same, about 12.78 PTB. Fuel compositions are prepared by dissolving the additive cocktails in a No. 2 fuel oil and in a turbine fuel. In Table II are shown the make-up of each antistatic additive in each fuel composition and the conductivities in picomhos/ meter of each fuel composition.

TABLE II Weight ratio, Conductivity, Antistatio additive Component picomhos/meter Component (a), Component Component No. 2 Turbine PTB (a) Fuel Fuel The data in Table I1 illustrate the synergistic interaction of components (a) and (b) of applicants antistatic additive. At a constant additive concentration, there is a maximum effectiveness as an antistatic agent at a weight ratio of component (b) to component (a) of about 3: 1.

The No. 2 fuel and the turbine fuel compositions will exhibit other desirable properties such as good water tolerance and improved thermal and oxidative stabilities.

While the instant invention has been illustrated by several specific examples, it will be understood that the antistatic additive and fuel compositions containing said additive may be varied within the set forth in the foregoing description. For example, the additive need not be prepared from a cocktail of component (a) or a concentrate of component (b) but instead may be prepared from the straight components. Also, while it is preferred that component (b) contain a monohydrocarbyl ether of a glycol, the ether may be omitted. In addition, the make-up of components (a) and (b) may be varied within the limits described, the ratio of component (b) to component (a) may be varied as disclosed, and the concentration of the additive in the hydrocarbon fuel composition may be within the range disclosed. It will be understood, therefore, that the above examples serve only to illustrate the invention and are not in any sense restrictive of the scope of the invention.

We claim:

1. An antistatic additive for normally liquid hydrocarbon fuels comprising the components:

(a) a hydrocarbyl hydrogen phosphate salt of a compound having the general formula wherein m is at least 1 and the sum of n plus m is from 2 to about 6, R is a multivalent hydrocarbon group of about 2 to about 50 carbons, R is a hydrocarbylene group of about 2 to about 12 carbons, R" is selected from the group consisting of hydrogen and hydrocarbyl groups of about 1 to about 30 carbons, R' is a hydrocarbyl group of from about 2 to about 12 carbons, and at least 10% of the amino groups contained therein are converted to the hydrocarbyl hydrogen phosphate salt; and (b) metal salts of a naphthetic acid plus an alkanoic acid wherein the metal is a mixture of a Group IIa metal and a transition metal selected from the group consisting of iron, cobalt, nickel, copper, and zinc. 2. The antistatic additive of claim 1 wherein in component (a) R is a multivalent hydrocarbon group of about 4 to about 34 carbons, R is a hydrocarbylene group of about 2 to about 6 carbons, R" is selected from the group consisting of hydrogen and hydrocarbyl groups of about 3 to about 24 carbons, R" is a hydrocarbyl group of about 2 to about 6 carbons, n is O and m is 2, and about 50% to about of the amino groups contained therein are converted to the hydrocarbyl hydrogen phosphate salt; and in component (b) the naphthenate contains about 16 to 24 carbons, the alkanoate contains about 6 to 10 carbons and is branched in the alpha-position, and there is in addition a monohydrocarbyl ether of a 1,2-glycol, said ether containing about 4 to 18 carbons.

3. An antistatic additive for normally liquid hydrocarbon fuels comprising the components:

(a) a hydrocarbyl hydrogen onthophosphate salt of a compound selected from the group consisting of and mixtures thereof wherein R is the C hydrocarbylene portion of the dimer of a polyunsaturated C 1 l monocarboxylic fatty acid, R is tallowyl, and about 50% to about 90% of the amino groups are converted to the hydrocarbyl hydrogen orthophosphate salt; and (b) metal salts of a naphthenic acid containing about 16 to 24 carbons plus an alkanoic acid containing about 6 to 10 carbons and which is branched in the alpha-position wherein the metal is a mixture of a Group Ha metal selected from the group consisting of calcium and barium and a transition metal selected from the group consisting of copper and zinc, and a monohydrocarbyl ether of a 1,2-glycol, said ether containing about 4 to 18 carbons, and wherein the mole ratio of naphthenate to alkanoate is from about 6:1 to about 1:2 and the mole ratio of the group He metal to the transition metal, as the metal, is from about 4:1 to about 6:1. 4. An antistatic additive for normally liquid hydrocarbon fuels comprising the components:

(a) a hydrocarbyl hydrogen orthophosphate salt of a compound selected from the group consisting of H o o H H R'D T(CH2):4I T- R( I T(CH2)sb 1R' R o B. H N-'(CHa)3 JR-( J-lil-(CH2)3NH2 o R R'I 1(CH2)3I Ii. /R -1 T-(CH2)sNH2 and mixtures thereof wherein R is the C hydrocarbylene portion of the dimer of a polyunsaturated C monocarboxylic fatty acid, R is tallowyl, the saltforrning hydrocarbyl hydrogen orthophosphate comprises about 65 Weight percent of diisooctyl hydrogen orthophosphate and about 35 weight percent of isooctyl dihydrogen orthophosphate, and about 50% to about 90% of the amino groups are converted to the hydrocarbyl hydrogen orthophosphate salt; and (b) a mixture comprising about 4.3 parts by weight of the monobutyl ether of ethylene glycol, about 4.3 parts by weight of toluene, and about 92.7 parts by weight of metal salts of a mixture of naphthenic acids containing about 16 to 24 carbons and having an average carbon content of about 20 plus Z-ethyl-hexanoic acid wherein the metal is a mixture of barium and zinc having a mole ratio, as the metal, of from about 4.5 :1 to about 5.5 :1 and the mole ratio of naphthenate's to Z-ethylhexanoate is from about 5:1 to about 3:1.

5. The antistatic additive of claim 2 wherein the weight ratio of component (b) to component (a) is from about 28:1 to about 1:15.

6. The antistatic additive of claim 3 wherein the weight ratio of component (b) to component (a) is from about 20:1 to about 1:2.

7. The antistatic additive of claim 4 wherein the weight ratio of component (b) to component (a) is from about 15:1 to about 1:1.

8. A normally liquid hydrocarbon fuel composition comprising a major proportion of a normally liquid hydrocarbon fuel and an antistatic amount of the antistatic additive of claim 1.

9. A normally liquid hydrocarbon fuel composition comprising a major proportion of a normally liquid bydrocarbon fuel and about 1 to 100 PTB of the antistatic additive of claim 5.

10. A normally liquid hydrocarbon fuel composition comprising a major proportion of a normally liquid bydrocarbon fuel and about 3 to PTB of the antistatic additive of claim 6.

11. A normally liquid hydrocarbon fuel composition comprising a major proportion of a normally liquid bydrocarbon fuel and about 3 to 25 PTB of the antistatic additive of claim 7.

12. The normally liquid hydrocarbon fuel composition of claim 11 wherein the normally liquid hydrocarbon fuel is a distillate fuel selected from the group consisting of No. 1 fuel, No. 2 fuel, diesel fuel, and turbine fuel.

References Cited UNITED STATES PATENTS 3,024,096 3/1962 Zech 4466 3,161,486 12/1964 Rogers et a1. 4468 3,240,009 3/1966 Walters 44DIG 1 FOREIGN PATENTS 749,898 6/ 1956 Great Britain 44DIG 1 DANIEL E. WY'MAN, Primary Examiner Y. H. SMITH, Assistant Examiner US. Cl. X.R.

4468, 72, 76, DIG l, DIG 4