US3433607A - Quaternary ammonium salts of esters of salicylic acid as rust inhibitors - Google Patents

Description

United States Patent 3,433,607 QUATERNARY AMMONIUM SALTS 0F ESTERS 0F SALICYLIC AClD AS RUST INHIBITORS Elizabeth L. Fareri, Pittsburgh, Robert J. McGuire, Monroeville, and Harold 0. Strange, Penn Hills Township, Allegheny County, Pa., assignors to Gulf Research & Development (Iompauy, Pittsburgh, Pa., a corporation of Delaware No Drawing. Filed Aug. 2, 1965, Ser. No. 476,717 US. CI. 44-63 8 Claims Int. Cl. C101 1/22 ABSTRACT OF THE DISCLOSURE Quaternary ammonium salts of esters of salicyclic acid are used as rust inhibitors in hydrocarbon oil.

This invention relates to chemical compounds and to compositions containing said compounds.

The chemical compounds of this invention are quaternary ammonium salts of esters of salicylic acid. These compounds have been found to exhibit high activity as rust inhibitors when present in a minor concentration in a hydrocarbon oil, such as fuel oil. The compounds of this invention are particularly effective rust inhibitors when present in a hydrocarbon oil which is in contact with a water phase or is otherwise in a condition conducive to rust formation.

The quaternary ammonium salts of esters of salicylic acid of this invention can be selected from compounds having the general structure wherein R is a normal or iso alkyl, normal or iso alkenyl, aralkyl or cycloalkyl substituent containing 1 to 22 carbon atoms and can be substituted with substituents such as nitrogen, phosphorus, sulfur or oxygen.

R may be absent or is a normal or iso alkyl, normal or iso alkenyl, aralkyl or cycloalkyl substituent containing 1 to 22 carbon atoms and can be substituted with substituents such as nitrogen, phosphorus, sulfur or oxygen.

R R R and R are each a normal or iso alkyl, normal or iso alkenyl, aralkyl or cycloalkyl substituent containing l to 22 carbon atoms which can be substituted with substituents such as oxygen, nitrogen, phosphorus, or sulfur, at least one of said groups containing at least four carbon atoms,

N is nitrogen and can be the nitrogen of a heterocyclic nitrogen-containing ring such as imidazoline, pyridine, thiazine or piperazine, in which case R and R are members of the heterocyclic ring and at least one of the substituents R and R contains at least four carbon atoms, C is carbon, and O is oxygen.

Although R,,, R R and R, generically encompass oxygen-containing substituents, compounds wherein R,,, R R and R are hydrocarbon substituents which are free of hydroxyl groups with or without an ether polymer thereof unexpectedly possess different utility from compounds wherein R R R and R have a hydroxyl group with or without an ether polymer thereof, and the latter group of compounds is covered specifically in application Ser. No. 476,666, filed on the same date as this application by Elizabeth L. Fareri, Robert J. McGuire and Edward Mitchell.

Preferred compounds of this invention include quaternary ammonium salts of octyl, dodecyl, tridecyl or hexadecyl salicylates where the quaternary ammonium group is selected from the following:

Alkyltrimethylammonium wherein the alkyl group is a C to C -substituent; dialkyldimethylammonium wherein the alkyl groups are C,,- to C -substituent; or mixtures of said monoalkyltrimethylammonium and said dialkyldimethylammonium groups.

Some commercial starting materials which can be utilized as the quaternary ammonium base are Arquad C, Arquad S, Arquad T, Arquad 12, Arquad 18, Arquad 2C, Arquad 2S, Arquad 2HT, Arquad T-2C, and Arquad S-2C, all of which are commercial products. Arquad C, Arquad S, Arquad T, Arquad l2, and Arquad 18 are alkyltrimethylamrnonium chlorides wherein the symbols C, S, and T indicate that the alkyl substituent comes from coco, soya bean oils or fats, or tallow, respectively, while in Arquad 12 and Arquad 18 the alkyl substituent is essentially pure dodecyl or octadecyl, respectively. Arquad 2C, Arquad 2S and Arquad 2HT are dialkyldimethylammonium chlorides wherein the alkyl substituent is coco, soya and hydrogenated tallow, respectively, and Arquad T-2C and Arquad S-2C are mixtures of the indicated alkyltrimethylammonium chlorides and dialkyldimethylammonium chlorides.

Salicylic acid is a convenient starting material in the preparation of the quaternary ammonium salicylates of this invention. Salicylic acid contains a hydroxyl radical and a carboxylic acid radical at ortho positions on a benzene ring. In preparing the quaternary ammonium salts of this invention, the reactant containing the quaternary ammonium cation is reacted with the hydroxyl radical of the salicyclic acid rather than with the carboxylic radial so that the salt formed is a quaternary ammonium phenate rather than a quaternary ammonium carboxylate. However, the carboxylic acid radical is considerably more acidic and therefore more reactive with the quaternary ammonium cation than is the hydroxyl radical and in order for the quaternary ammonium cation to react with the hydroxyl radical rather than with the carboxylic acid radical the salicylic acid must be esterified prior to the reaction thereof with the quaternary ammonium compound. Therefore, the preparation of the quaternary ammonium salt of this invention is a two-step process in which the order of performance of the steps is critical, i.e., the salicylic acid starting material is first esterified by reaction with an alcohol and only after esterification is it converted to a quaternary salt.

In the following specific example for the preparation of the compounds of this invention from salicylic acid, the more reactive carboxylic acid radical is first reacted with an alcohol to form an ester. Thereupon, a commercial quaternary ammonium chloride is converted to the corresponding quaternary ammonium hydroxide. The quaternary ammonium hydroxide is then reacted with the hydroxyl radical of the ester of salicylic acid to form a quaternary ammonium salt of salicylic acid ester.

EXAMPLE Step 1.Preparation of isooctyl salicylate from salicylic acid A mixture containing 900 grams of salicylic acid, 1300 grams (10 moles) of isooctyl alcohol, 30 grams of p-toluenesulfonic acid and 1000 milliliters of toluene was heated at reflux in a 5-liter flask fitted with a Dean and Stark trap. Reflux was continued until no more water collected in the trap. The solution was cooled to room temperature and extracted with one liter of water, then with one liter of 10 percent sodium bicarbonate solution followed by a washing with one liter of water. The extracted solution was dried over anhydrous sodium sulfate, filtered and vacuum-distilled. After distillation of toluene and excess isooctyl alcohol, 1568 grams of a clear oil was collected at l50-l60 C. and 3.2 millimeters pressure. Analysis of the product showed 72.21 percent carbon, 8.90 percent hydrogen, 18.21 percent oxygen and a molecular weight of 265. Theoretically, isooctyl salicylate contains 71.9 percent carbon, 8.8 percent hydrogen, and 19.2 percent oxygen, and has a molecular weight of 250.

Step 2.-Preparation of di(hydrogenated tallow)dimethylammonium isooctyl salicylate from isooctyl salicylate Ninety grams (0.154 mole) of di(hydrogenated tallow)dimethylammonium chloride as a 75 weight percent paste containing isopropanol and a small amount of water, was dissolved in 200 milliliters of benzene. The composition of the 75 weight percent of the paste which consisted of di(hydrogenated tallow)dimethylammonium chloride was 75 percent by weight distearyldimethylammonium chloride, 1 percent by weight dioctadecenyldimethylammonium chloride, and 24 percent by weight dihexadecyldimethylammonium chloride. With stirring, a warm solution containing 10.1 grams (0.153 mole) of potassium hydroxide (assay 85%) in absolute ethanol was added to the benzene solution. The precipitated potassium chloride was removed by filtration. To the filtrate was added 38.4 grams (0.153 mole) of isooctyl salicylate. Solvent was removed. The product, a brown oil which solidified on cooling, contained 1.81 percent of nitrogen. The calculated nitrogen content of di(hydrogenerated tallow)dimethylammonium octyl salicylate is 1.75 percent.

Tests were conducted to illustrate the high rust arresting effectiveness of the compounds of this invention as compared to a control fuel oil sample without additives and as compared to a control fuel oil sample containing calcium octyl salicylate. In conducting these tests, a test solution was prepared by placing a mixture of 80 percent by volume of fuel oil or fuel oil plus additive with 20 percent by volume of distilled water into a 4-ounce jar and shaking vigorously for one minute. A clean specimen of SAE 1020 steel was immersed nearly vertically into each test jar and the jar was stored at room temperature. The steel specimens were inspected and rated after 1 day, 3 days and 7 days, respectively, and the results of the inspection are shown in the following table. A rating of signifies no rust; 1 signifies 1 to percent of the surface area rusted; 2 signifies 6 to 25 percent of the surface area rusted; 3 signifies 26 and 50 percent of the surface area rusted; and 4 signifies greater than 50 percent of the surface area rusted. The results of the tests are presented in the following table,

1 day 3 days 7 days Sample Fuel Water Fuel Water Fuel Water oil layer oil layer 011 layer layer layer layer Fuel oil control 2 0 4 0 4 0 4 Fuel oil control plus calciuin iso octyl d salicy ate, 30 poun s per 1,000 barrels..." 0 4 0 4 0 4 Fuel oil control plus di(hydrogenated tallow) dirnethyl ammolnium isooctydl salicy ate, 20 poun 5 per 1,000 barrels 0 1 0 1 0 1 1 Heavy red and black corrosion where water droplets cling to or creep over portion of steel specimen in the fuel 011 phase.

2 Typical fuel oil inspections:

Gravity: API, AS'IM D287 End Point. 632 At 10 F 434 At 50 F 502 At F. 590 Residue 1.0

It is seen from the above table that in the test with the fuel oil control sample without additives and in the test with the fuel oil control sample plus calcium isooctyl salicylate there was rusting over more than 50 percent of the surface area of the steel specimen in the water phase and also heavy corrosion in the steel specimen in the fuel oil phase where water droplets clung to or crept over the portion of the specimen in the fuel oil phase. In contrast, the table shows that in the test with the fuel oil sample plus di(hydrogenated tallow)dirnethylammonium isooctyl salicylate there was rusting over only 1 to 5 percent of the surface area of the steel specimen in the water phase, while there was no rust in the portion of the steel specimen in the fuel oil phase.

The quaternary ammonium salicylates of this invention are oil soluble and can be present in hydrocarbon oils over a wide range of concentrations. For example, they can be generally present in hydrocarbon oils over a concentration range of about 0.002 up to about 10 percent by Weight, the higher region of the range being especially useful when preparing a concentrate, or, preferably, over a concentration range of about 0.005 to about 0.1 percent by weight. Although useful in a wide variety of hydrocarbon oils such as gasoline, jet fuels, diesel fuels, etc., the quaternary ammonium salicylates of this invention are especially useful in fuel oils, such as blends of straight run and catalytically cracked fuel oils. Also, the compounds of this invention are primarily useful for rust inhibition in oils which are in contact with an aqueous phase.

Various changes and modifications can be made without departing from the spirit of this invention or the scope thereof as defined in the following claims.

We claim:

1. A composition comprising a hydrocarbon oil in contact with water having dissolved in said oil an oil soluble quaternary ammonium salt of an ester of salicylic acid, said salt being a quaternary ammonium phenate with the ester portion thereof formed from an alcohol containing 1 to 22 carbon atoms.

2. The composition of claim 1 wherein there is attached to the ring structure of said salicylic acid in alkyl, alkenyl, aralkyl or cycloalkyl substituent containing 1 to 22 carbon atoms.

3. The composition of claim 1 wherein attached to the quaternary nitrogen atom are four hydroxyl-free substituents selected from the group consisting of alkyl, alkenyl, aralkyl, and cycloalkyl substituents containing 1 to 22 carbon atoms, at least one of said substituents containing at least 4 carbon atoms.

4. The composition of claim 1 wherein said hydrocarbon oil is fuel oil.

5. The composition of claim 1 wherein the concentration of said quaternary ammonium salt of an ester of salicylic acid in said hydrocarbon oil is between about 0.002 and percent by weight.

6. A composition comprising a hydrocarbon oil in contact with water having dissolved in said oil a compound having the structure.

wherein R is a substituent containing 1 to 22 carbon atoms, R and R are each substituents containing 1 to 22 carbon atoms, at least one of which contains at least 4 carbon atoms, and R and R are members of the same heterocyclic ring containing the quaternary nitrogen atom.

8. A composition comprising a hydrocarbon oil in contact with water having dissolved in said oil about 0.002 to 10 percent by weight of a compound having the structure wherein R is an alkyl, alkenyl, aralkyl or cycloalkyl substituent containing 1 to 22 carbon atoms, R R R and R are each hydroXyl-free alkyl, alkenyl, aralkyl or cycloalkyl substituents containing 1 to 22 carbon atoms,'at least one of which contains at least 4 carbon atoms, and R is an alkyl, alkenyl, aralkyl or cycloalkyl su-bstituent containing 1 to 22 carbon atoms.

References Cited UNITED STATES PATENTS 2,629,649 2/ 1953 Wachter et a1. 252-392 2,679,500 5/1954 Gash et a1 260-243 2,739,871 4/ 1956 Senkus 252-392 2,745,809 5/1956 Cardwell et al. 252-392 2,831,019 4/ 1958 Erskine 252-392 2,861,874 11/1958 OKelly et a1. 44-66 2,920,040 1/ 1960 Jolly 252-392 DANIEL E. WYMAN, Primav'y Examiner.

Y. H. SMITH, Assistant Examiner.

US. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,433,607 March 18, 1969 Elizabeth L. Fareri et a1.

It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below: Column 2, line 49, "radial" should read radical Column 6, lines 4 to ll, the portion of the formula reading:

\ -N should read --N+-- signed and sealed this 31st day of March 1970.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer