2,972,526 RUST-INHIBITED PETROLEUM DISTILLATE FUEL Fred K. Kawahara, Park Forest, 111., assignor to Standard Oil Company, Chicago, 111., a corporation of Indiana No Drawing. Filed Nov. 4, 1957, Ser. No. 694,113
2 Claims. (Cl. i t-64) This invention relates to a petroleum distillate fuel which is inhibited against rust formation and it pertains more particularly to an improved kerosene or heater oil composition.
An object of the invention is to provide an anti-rust additive for distillate fuel oils and/or a distillate fuel oil composition which will inhibit the formation of rust in storage containers and/or in systems wherein the oil is exposed to iron surfaces. In other words, an object of the invention is to provide a distillate fuel which will pass the iron strip anti-rust test, hereinafter described, by inhibiting rust formation for a period of at least 7 days in both oil and water phases. A further object is to provide such an oil in which the anti-rust component is not prohibitive in cost and in which said component does not deleteriously affect other properties of the distillate fuel oil, i.e. one which will not be ruled out by ordinary distillate fuel oil specifications.
My anti-rust additive is preferably a mixture of approximately equimolar amounts of a long chain condensed fatty acid material such, for example, as linoleic acid dimer and a hydrazone such, for example, as diisobutyl ketone hydrazone. The mixture may be marketed or used as a concentrate but in the ultimate distillate fuel it is present on a weight basis in amounts of the order of to 50, preferably about 10 to 30, parts per million such, for example, as 5 pounds per 1,000 barrels of oil. The condensed fatty acid material is preferably a dimer and/or trimer of linoleic acid, C H COOH, or a carboxylic acid material having similar properties. By approximately equimolar I mean a molar ratio in the range of about 3:1 to 1:3. Other hydrazones which may be employed instead of diisobutyl ketone hydrazone (although not necessarily the equivalent thereof) are those obtained by reacting a hydrazine and a compound where R and R may be hydrocarbon radicals such, for example, as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, amyl, isoamyl, phenyl, etc., R and R may be the same or different radicals, and either R or R but not both may be hydrogen. Hydrazine derivatives containing such hydrocarbon radicals, i.e. dibutyl hydrazine, tributyl hydrazine or other alkyl hydrazine may be em= ployed in place of the described hydrazones.
The distillate fuel to which my invention relates is a hydrocarbon boiling in the range of 200 to 700, and preferably in the range of 300 to 600 F., and the preferred examples are kerosene and heater oil. It has been 'found, for example, that the invention is not applicable to certain gasoline compositions and the advantageous results of the invention are not necessarily attained with higher boiling oils. The preferred distillate fuels have an initial boiling point in the range of about 300 to 375 F., a percent point which is at least about 465 F. and an end point which is preferably in the range of about 500 to 650 F. The distillate fuel of my invention should have an A.P.I. gravity of at least about 40 and a flash point by the Tag closed cup method not lower than F. and preferably above F. Such distillate fuel oils, e.g. kerosene or heater oil, may be stored in iron containers in the presence of moisture and it is desirable that no rust be formed on iron which is either in contact with the oil or with a water phase. The following test procedure was employed for determining anti-rust properties of various compositions: iron test strips were cleaned with emery cloth, then with fine sand paper and then with steel wool, after which each strip was wiped clean with a cellulose material and kept in a desiccator prior to use. The ends of the iron strips were cut to remove the portion which might not have been freed from rust. Into 100 ml. tall-form bottles I added a 50 ml. sample of the oil to be tested. Next the anti-rust additive was introduced in the form of a 1 weight percent solution in xylene, 0.1 ml. of such solution being equivalent to 5 pounds of anti-rust additive per thousand barrels of oil. Next the test strip was placed in the oil sample in the bottle for 30 minutes at an angle and then 10 ml. of boiled, distilled water was added to each bottle and the bottles were stoppered with corks. Each bottle was rolled for one minute and then allowed to stand upright for 7 days. Visual observation was made at 30 minutes, 4 hours, and other time intervals. Results of such tests were as follows:
Efiect of additives in heater oil (5 lbs./1000 bbls.)
OIL PHASE 30 Min. 4 hrs. 16 hrs 7 days Commercial Additive Clean Clean Clean Clean. Linoleic Acid Dimer+Dl-ido do do Do.
Butyl Ketone Hydrazone. Di-i-Butyl Ketone Hydra- Rust, 15 specks- Rust Rust, 7 spots Rust.
Z0118. Linoleic Acid Dimer Clean Clean Rust, 1 spot Rust, 1 spot.
WATER PHASE Commercial Additive Clean Clean Rust, 1 spot Rust-l-lron hydroxide precipitate. Llfioleifcld Dzine-r-l-DH- do do (lean Clean.
uty etone y azone. Di-i-Butyl Ketone Hydrado ..do Rust, 3 spots Rust. Liiililgie Acid Dimer do Slight Rust..- Rust Iron Hydroxide Rust Precipitate.
Precipitate.
containing a carbonyl group to obtain a product which may be represented by the formula R E=N-NH2 The commercial additive is one which is believed to be very good as an anti-rust in distillate fuels but it will be 70 noted that when a water phase is present a rust spot developed within 16 hours and rust accompanied by iron hydroxide precipitate was in evidence at the end of 7 days. My improved additive, namely linoleic acid dimer and diisobutyl ketone hydrazone in approximately equimolar amounts, resulted in clean iron test strips for the entire 7 days test period in both the oil and Water phases. Neither component of my additive, however, is efiective by itself. The heater oil inthe above example was a sweetened commercial product containing about 1 pound of conventional metal deactivator per 1000 barrels. The anti-rust agents in the foregoing tests were employed in amounts of about 18 parts per millon parts of heater oil on a weight basis; with some test oils effective anti-rust may be attained with amounts as low as 5 parts per million while other heater oils and/ or compositions may require as much as 50 parts per million of the anti-rust material. In no case,however, is the treating cost prohibitive and in no case does the anti-rust material dele teriously atfect other properties of the distillate fuel.
As another example of my invention, I may add an approximately equimolar amount of dibutyl hydrazine to a linoleic acid dimer or trimer and employ the resulting composition in amounts of about 5 to 50 parts per million in kerosene or heater oil.
I claim:
1. A distillate fuel of the heater oil boiling range which contains about 5 to 50 parts per million on a weight basis of an approximately equimolar mixture of a condensed fatty acid material selected from the class consisting of linoleic acid dimer, linoleic acid trimer and mixtures of linoleic acid dimer and trirner, and a composition represented by the formula Rb=N-NH; where R and R are each selected from the group consisting of hydrogen and methyl, ethyl, propyl, isopropyl, butyl, isobutyl, amyl, isoamyl and phenyl hydrocarbon radicals and at least one of said R and R is one of said hydrocarbon radicals.
2. A distillate fuel of the heater oil boiling range which contains about 5 to parts per million on a weight basis of an approximately equimolar mixture of a condensed fatty acid material selected from the class consisting of linoleic acid dimer, linoleic acid trimer and mixtures of linoleic acid dimer and trimer, and diisobutyl ketone hydrazone.
References Cited in the file of this patent UNITED STATES PATENTS