US2921843A - Non-corrosive fuels - Google Patents

Description

United States Patent Q NON-CORROSIVE FUELS Joseph E. Fields and George W. Zopf, Jr., Dayton, Ohio, assignors to Monsanto Chemical Company, St. Louis, Mo., a corporation of Delaware N Drawing. Application November 19, 1956 Serial No. 622,756

2 Claims. (Cl. 44-77) This invention relates to non-corrosive fuel oils and deals more particularly with liquid petroleum distillate fuels which have been rendered non-corrosive and to methods of inhibiting rust formation by said liquids under static and dynamic conditions.

Corrosion of metal tanks in which hydrocarbon fuels, i.e., kerosene and gasoline, are stored frequently occurs owing to the presence of traces of moisture therein, e.g., as a result of refinery practices or due to the condensation of moisture-laden air in partially filled tanks. Metal pipelines through which the fuels are transported often have a film of Water droplets upon the inside Walls thereof as a result of temperature changes which are conducive to separation of dissolved water. In aviation gasoline water may appear in a separate phase by entrainment from fueling pumps or as the result of moisture condeusation in the fuel tank at high altitude temperatures. Acidic additives, traces of refinery acid, or small quantities of acidic combustion products may also be responsible for corrosion of metals in petroleum fuel systems.

Corrosion of fuel-handling equipment poses problems of considerable magnitude. Internal rust and corrosion of pipelines produces two adverse effects: products are contaminated with rust Particles and pipeline capacity is progressively reduced. Besides indicating loss of metal, the rust particles which are formed and suspended in the fuel are highly abrasive; hence there ensues erosion of pumps, valves, meters and other expensive equipment. Frequent overhaul of line meters is necessitated.

In storage systems including pipeline terminal tanks, bulk storage tanks and service station and consumer tanks, corrosion of the metallic containers results not only in deterioration of these storage facilities but also in contamination of the fuel.

In oil tankers, the clean-service life of cargo tanks and tankers is often reduced as much as 50 percent owing to tanker hold corrosion.

Rust in motor fuels is of concern to both automotive and aviation industries in that the suspended rust particles are extremely damaging to carburetors and fuel pumps. Rust particles not trapped by fuel filters often contribute to engine Wear because these particles are generally unaffected by combustion.

Accordingly, an object of the invention is to protect liquid petroleum fuel handling facilities against corrosion. Another object is the prevention of rust deposition in sa d fuel when stored in heavy metal, e.g., iron, steel, brass, copper or zinc containers, or transferred in metal pipelines. Still another object of the invention is the prevention of eroding suspensions of rust in petroleum hydrocarbon fuels.

These and other objects hereinafter disclosed are provided by the following invention wherein there is incorporated with the fuel a small amount, say from 0.0001 percent to a 0.01 percent of a dimeric mono-alkyl ketene having from 8 to 18 carbon atoms in the alkyl radical, e.g., n-octyl ketene dimer, Z-ethylhexyl ketene dimer,

isononyl ketene dimer, n-decyl ketene dimer, n-hendecyl ketene dimer, Z-butyloctyl ketene dimer, tert-dodecyl ketene dimer, n-tetradecyl ketene dimer, 7-ethyl-2-rnethyl hendecyl ketene dimer, n-tetradecyl ketene dimer, nhexadecyl ketene dimer, n-heptadecyl ketene dimer, noctadecyi ketene dimer, etc. he presently useful alkyl ketene dimers are known compounds which are obtainable, e.g., by the dehydrohalogenation of acid halides.

The following specific examples illustrate the effectiveness of the presently disclosed mono-alkyl ketene dimer as a corrosion preventative in gasoline.

Example 1 This example describes evaluation of the rust-inhibiting properties of a hexadecyl ketene dimer supplied by Hercules iowder Company and reported by the supplier to possess the following characteristics:

Apparent molecular weight: About 530 Physical form: Flaked solid Color: Almost white Melting point: 110 F.

Bulk density: About 25 pounds per cubic foot in flaked form.

3 X /4" 1; 20 gauge low carbon cold rolled steel specimens which had been cleaned with gasoline, sand blasted to a fresh uniform surface, boiled in methanol and stored in a desiccator were placed in clean 4-02. bottles containing ml. of gasoline into which had been incorporated varying amounts of hexadecyl ketene dimer, respectively. Each of the bottles was shaken moderately for 3 minutes and allowed to stand for 30 minutes. To each bottle there was then added 3 ml. of water and the resulting mixtures were shaken for 3 minutes. The bottles with their contents were allowed to stand for 24 hours at room temperature and the respective specimens were then removed therefrom. After washing them with gasoline and acetone they were examined under a 100- watt daylight bulb for rust dots and/or rusted areas. Specimens which had thus been immersed in the presence of either 10 p.p.m., 30 p.p.m., or 100 p.p.m., of the hexadecyl ketene dimer were completely clean, no evidence of rusting being present.

Example 2 This example describes evaluation of the water tolerance of isooctane containing hexadecyl ketene dimer as a rust inhibitor. To ml. of the isooctane containing an 0.008% concentration of said dimer there was added ml. of distilled water at room temperature. The whole was then shaken vigorously for 2 minutes without swirling and then allowed to stand on a vibration-free surface for 5 minutes. Observation of the test sample at the end of that time showed that the isooctane had separated sharply from the water layer and that there was no evidence of an emulsion, precipitate, or suspended material within or present with the isooctane or the water layer. No change in the volume of either layer was observed.

T results in Examples 1 and 2 above clearly demonstrate that hexadecyl ketene dimer is a very effective inhibitor of corrosion when incorporated into gasoline and that its use in fuels containing water does not lead to any problems of emulsifying or decomposition.

instead of employing hexadecyl ketene dimer in the production of the present non-corrosive hydrocarbon fuels there may be employed other alkyl ketene dimers or mixtures of such dimers in varying proportions e.g., dodecyl ketene dimer, a mixture of n-octyl and 2-ethylhexyl ketene dimer, tetradecyl ketene dimer, octadecyl ketene dimer, etc. The dimers are effective metal'corrosion incarbonfu'els generally, and are especially valuable when used with light gasoline fractions and particularly with fuels having a high octane rating e.g., those intended for use'in'e'ngines' of high compressor efiiciency. The present rust inhibitors'are efiective in motor gradegasol'mes in which the presence of water is merely incidental as well as in 'jet fuels in which water and methanol may be customarily employed components. 7

"Addition of the present alkyl ketene dimers to the fuel stock may be eifected in several ways, but most con veniently :the dimer is added to the stock at the time of blending with other additives, e.g., anti knock additives such as tetraethyl lead, the anti-foam additives such as the silicones, etc. The present dimers are very stable compounds which apparently are not affected by, nor

react with, other additives generally employed in the preparation of fuel blends. When employing the dimers as anti-corrosive agents in pipelines the dimer may be added as desired at various points of the system, but because the alkyl ketene dimers are effective in very small concentrations and because they are not adversely affected by Water it is more convenient to incorporate the dimer into the fuels only as they enter the system, for example by means of a proportioning pump.'

What we claim is: I I a l. A non-corrosive fuel consisting essentially of a normally liquid petroleum distillate containing a corrosion-inhibiting amount of a dimeric mono-alkyl ketene having from 8 to 18 carbon atoms in the alkyl radical.

2. A non-corrosive fuel consisting essentially of a normally liquid petroleum distillate containing, a'corrosion-inhibiting amount of hexadecyl kete ne dimer.

References Cited in the file of this patent UNITED STATES PATENTS 2,430,058 Klaber Nov. 4, 1947 2,627,477 Downey Feb. 3, 1953 OTHER REFERENCES 7 Chemical Trade Names and Commercial Synonyms,

Haynes, Second Ed., October 1955, Van Nostrand Co., N.Y., p. 72. a

Claims (1)

1. A NON-CORROSIVE FUEL CONSISTING ESSENTIALLY OF A NORMALLY LIQUID PETROLEUM DISTILLATE CONTAINING A CORRISION-INHIBITING AMOUNT OF A DIMERIC MONO-ALKYL KETENE HAVING FROM 8 TO 18 CARBON ATOMS IN THE ALKYL RADICAL.