US2819954A

US2819954A - Rust inhibitor formulation

Info

Publication number: US2819954A
Application number: US358178A
Authority: US
Inventors: Charles F W Gebelein; Harry W Rudel; Gargisa Marion
Original assignee: Exxon Research and Engineering Co
Current assignee: ExxonMobil Technology and Engineering Co
Priority date: 1953-05-28
Filing date: 1953-05-28
Publication date: 1958-01-14
Anticipated expiration: 1975-01-14

Description

RUST INHIBITOR FORMUIJATION Charles F. Gebelein, Fanwood, Harry W. Rude], Rosellqand Marion Gargisa, Elizabeth, N J a'ssignors to Esso'Researclr' and Engineering" Company, a corporation of Delaware No Drawing. Application Mayzzs, v1953 Serial No. 358,178

4 Claims. (Cl; 44-7 5) Thepresenrinventien is concerned" with a method and compositiomfo'r' inhibiting, the rusting. characteristics of petroleum'distillates. The' rust inhibitorsutiliz'ed in the present'invention" are directly dissolved in the petroleum distillateso as '"to' substantially completely eliminate any rusting of ferrous surfaces'in the presence of the distillate'product. 'The'additives utilized'are related broadly tdthose' disclosed in'a plic'ation, Serial'No. 325,694, tiledDecernber 12, 1952,:and nowU. S. 2,791,495;- for HarrywaRudeliandfMarion Gargisa, entitled Rust Inhibited Distillate Products. The additives covered in the present application constitute a mixture of an ammonium salt of an alkylated behzen'esulr'onate with an ammonium salt'of alkyl'phosphoric acid. When utilizing these two classesof compoundsin conjunction with one another; an unexpectedvery. desirable synergistic effect is secured with respect to their rust preventive qualities;

One problem which exists in the handling and use of petroleum products .is the rusting which frequently occurs in storage containers such as pipelines, storage tanks, engines, etc.. In order to reduce and overcome the problems, many solutions have been suggested. As amatter of fact, a great amount of technical consideration is now being given to the discovery of effective rust inhibitors for petroleum products. The rusting problem which occurs in storing and using petroleum products occurs usually as the result of'traces of moisture which are inevitably present in petroleum distillates. Moisture finds its way into the distillates in a variety. of ways.

wane water is not appreciably soluble in petroleum distillatestraces of moisture are, in fact," dissolved in heating oil,. gasoline, kerosene, etc. Again,.it is impossible-to prevent entrainment of moisture in-such products during storage and handling. In this connection, .for example,.storage tanks are generally provided with breather devices to permit the intake and exhaust of air during atmospheric temperature changes. As a result;cool,,moisture-laden air is generally drawn into a storage tank at'night, resulting in the condensation of moisture in the tank. A portion of this moisture is dissolvedinor entrained inpetroleum products when pumped from the storage tanks.

There havebeen a number of suggestions for overcoming the corrosion due to moisture carried by oil products. For. example, anumber of water-soluble rust inhibitors are known and have been employed. Use of water-soluble inhibitorsisdisadvantageous for several reasons,- however- Theinhibitor is largely lost when water is separated fromoil products during handling so that the desired'rust inhibition for remaining residual traces ofwatet may'be lost. AddltlOlT of water-soluble inhibitors to oil again necessarily requires=addition-of water to the oil which aggravates the problem intended to be solved. It is therefore a particular object of this invention to provide a rust inhibitor which is soluble in the oil product to be inhibited.

It may be observed that attempts have been made in 2. the' past to provide suitable oil-soluble rust inhibitors. The problem ofv providing such an inhibitor is complicated by a number of factorshowever. It is clearly necessary that the-inhibitor-should not degrade the oil product, and thus, should-not decrease-the octane number of a gasoline for example, and-should not otherwise afiect critical inspections offthe oil products. In this connection a particular problem encountered with gasoline rust inhibitors is the tendency ofm'anyinhibitors to discolor dyed gasoline- A more specific object of this invention therefore is to'provide an oil-soluble rust inhibitor which will suitably inhibit'the oilproduct against rusting, while in no way affecting the critical inspections or characteristics of the oil product.

Theseobjectives are' satisfied in accordance with this invention by. a two-component rust inhibiting composh tion. Themake-up of this compositionis based on the discovery that two particular'classes ofrust inhibitors are beneficially employed in cornbinationto obtain rust inhibiting characteristics unobtainable by use of single components selected from eitherclass of inhibitors. in other words, the invention is'ba'sedon thediscovery of a synergistic action between two classes of rust inhibitors. In this combination one inhibitor constitutes an armmonium salt of-an alkylated benzene sulfonate.

The ammonium salt or'soap is preferably a sulfonate ofbenzene which has been alkylated with a poly-propylene. The poly-propylene preferably contains from about 9 to 15 carbon atoms in 'the'molecule. These polymers, as for example thetetra-propylene polymer, may be secured by any satisfactory polymerization operation. One satisfactorymethod of polymerizing light hydrocarbons, such as propylene and the like, is to utilize the socalled U. 0. P. process. In'essence, this'operation comprises passing light hydrocarbon gas containing propylene in contact with the polymerization-catalyst such as phosphoric acid impregnated on kieselguhr, silica gel, and the like. Temperatures are in the-ra'ngeof about 300 F. to 500 F., preferably about 450 F. The pressures may vary in the range from about 200 to 5,000 lbs/sq. in. gauge.

The alkylated'benzene is prepared by alkylating benzene with a polymerized light hydrocarbon such as, for example, with tetra-propylene polymer prepared as described above. In a typical preparation, 5 moles of tetra-propylene are added portion-wise to an agitated mixture of onemole of benzene, 0.2 mole of anhydrous aluminum chloride, and 0.05 mole of chloroform. The reaction temperature is maintained preferably below about 50 C. Afterthe addition, which requires about 0.5 hour, the'reaction' mixture-is stirred for about an additional 0.5 hour. The product is washed with water, dried and distillal. The distillation is first carried out at atmospheric pressure to remove the unreacted benzene and tetra-propylene. The distillation is then carried out under reduced pressure'to collect the mono-alkylated benzene. The bottoms boiling above 320 C. at 760 millimeters are'employed in the sulfonation step.

In the sulfonation step the alkylated benzene, prepared as described above, is treated portion-wise with rapid agitation with '50 volume percent of 20% oleum maintained in the reaction temperature below about 50 C. during the addition. After the addition of theoleum, the insoluble acid sludge-is allowed to-settle out and the sulfonated product decanted off.-

The ammonium 'salt'of-the sulfonated product is formed by bubbling ingaseous ammonia until absorption is complete.

The second constituent of the rust inhibiting composition of the present invention is an ammonium salt of alkyl phosphoric acid. The preferred salt is an ammonium salt of C oxo phosphoric acid. As used herein, the terms alkyl and aliphatic include cyclo-alkyl,

and cycle-aliphatic. These acids are preferably prepared by the reaction of P with an alcohol. The preferred alcohols to be reacted are the monohydric primary alcohols having 6 to 18 carbon atoms. While aliphatic alcohols of this character are preferred, aryl alcohols may also be employed. The reaction between P 0 and the alcohol results in the formation of what may be called esters or acid-esters of phosphoric acid. Depending upon the reactant proportions and the reaction conditions, mono-, di-, or tri-alkyl phosphoric acids may be obtained. Practically the reaction product constitutes a mixture of these esters. For this reason this constituent of the rust inhibiting composition is best defined as the ammonium salt of the reaction product of P 0 and an alcohol.

The two-component rust inhibiting composition may also be prepared by mixing the alkylated benzene sulfonic acid with an alkyl phosphoric acid and forming a mixed salt of these acids. As examples of this procedure, ammonia may be reacted with the mixed acids to form mixed ammonium soaps of the sulfonic acid and alkyl phosphoric acid.

In order to obtain the desired synergism between the ammonium salt of hydrocarbon sulfonic acid and the ammonium alkyl phosphoric acid salt, these constituents should be combined in proportion ranging from about i to l, to 1 to 3 respectively by weight.

The combined rust inhibiting additives, in the ratios indicated, may be employed economically in petroleum products in the concentration of about pound per 1,000 barrels up to pounds or more per 1,000 barrels. In this range of concentrations it is generally suitable and preferred to use a concentration of about 1 to 5 pounds of combined rust inhibitors per 1,000 barrels of product. Of course, in special circumstances where the primary function of the oil composition may be that of rust prevention, it is practicable and desirable to use higher concentrations of the combined rust inhibiting additives up to the limit of their solubility in oil. The oil products which may be successfully inhibited in this way may be defined as the distillate petroleum products. Thus, the oil product may constitute gasoline, kerosene, lubricating oil, heating oil, gas oil, etc.

in order to demonstrate the utility and benefits of this invention, the following examples are presented. In these a rusting test was employed which generally corresponds to A. S. T. M. test method D665. This test was modified however, by lowering the temperature to 77 F. The test required stirring of a mixture of 300 cc. of oil product with cc. of distilled water at 77 F. with a cylindrical steel rod immersed therein. At the end of 24 hours the rod was examined and rated in accordance with the amount of rust which had formed.

in a series of tests which were conducted, the ammonium salt of an alkylated benzene sulfonic acid prepared as described above was employed as the first con stituent of the rust inhibiting composition. The second constituent constituted the ammonium soap of di-alkyl phosphoric acid formed by the reaction of one mole of phosphoric pentoxide and four moles of iso-octyl alcohol synthesized by the OX0 process. The olefin feed to the OX0 process was a C copolymer of propylene and nbutylene. To obtain the alkyl phosphoric acid, 66 g. of phosphorus pentoxide was added portionwise with stirring to 260 g. of iso-octyl alcohol at about 60 C., following which stirring was continued for 2 hours at 60 C. The reaction product was heated to 140 C. and blown with nitrogen under reduced pressure for 4 hours to expel unreacted alcohol and water formed during the reaction. To prevent darkening the productduring the TABLE Modified A. S. T. M. rust tests [Blends in 100/130 aviation gasoline] inhibitor (3 pounds/ 1000 bbls.): Rust test rating Ammonium alkyl benzene sulfonate R-S Ammonium C Oxo phosphate R-4 ammon. alkyl benzene sulfonate, 50%

ammon. C OX0 phosphate R-l 33 /s% ammon. alkyl benzene sulfonate,

66% ammon. C OX0 phosphate R-l 25% ammon. alkyl benzene sulfonate, 75%

ammon. C OX0 phosphate R-1 None R-7 Test procedure involves a modification of ASTM Method D-665 in which a mixture of 300 cc, of product and 30 cc. of distilled water are stirred in contact with a polished steel rod for 24 hours at 77 F. The extent of rusting is rated as follows:

R1-free of rust R-2-trace rust R3-less than 5% of surface rusted R-4-5 to 50% of surface rusted R-55099% surface rusted R-G-surface covered with light rust R7surface covered with rust From the above, it is apparent that a synergistic rust preventive effect is secured by the use in combination of the compounds covered by the present application. While the antirusting effect is secured with respect to any petroleum distillate such as gasoline, kerosenes, heating oils and the like, it is particularly effective when used in conjunction with motor fuels and heating oils.

What is claimed is:

1. A petroleum distillate fuel having incorporated therein as a rust inhibiting additive in a concentration of about A to 25 pounds per 1000 barrels of distillate a mixture of one part by weight of an ammonium polypropyl benzene sulfonate wherein the polypropyl group contains from 9 to 15 carbon atoms and from one to three parts by weight of an ammonium isooctyl phosphate.

2. A fuel as defined by claim 1 wherein said am"- monium isooctyl phosphate is ammonium di-isooctyl phosphate.

3. A fuel as defined in claim 2 in which the polypropyl group is a tetra-propylene polymer.

4. A fuel as defined in claim 3 in which the amount of mixture employed is about 1 pound to 5 pounds per thousand barrels of distillate.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Industrial and Engineering Chemistry, May 1948, pages 890-897.

Claims

1. A PETROLEUM DISTILLATE FUEL HAVING INCORPORATED THEREIN AS A RUST INHIBITING ADDITIVE IN A CONCENTRATION OF ABOUT 1/4 TO 25 POUNDS PER 1000 BARRELS OF DISTILLATE A MIXTURE OF ONE PART BY WEIGHT OF AN AMMONIUM POLYPROPYL BENZENE SULFONATE WHEREIN THE POLYPROPYL GROUP CONTAINS FROM 9 TO 15 CARBON ATOMS AND FROM ONE TO THREE PARTS BY WEIGHT OF AN AMMONIUM ISOOCTYL PHOSPHATE.