US3418092A - Inhibited distillate fuel oils - Google Patents

Description

United States Patent 3,418,092 INHIBITED DISTILLATE FUEL OILS Harry J. Andress, Jr., Pitrnan, and Paul Y. C. Gee, Woodbury, N.J., assignors to Mobil Oil Corporation, a corporation of New York No Drawing. Continuation-impart of applications Ser. No.

188,564, and Ser. No. 188,580, Apr. 18, 1962. This application May 13, 1965, Ser. No. 455,610

6 Claims. (Cl. 44-71) ABSTRACT OF THE DISCLOSURE Petroleum distillate fuel compositions are provided containing, as rust inhibitors and detergents, small amounts of amino acids having alkyl groups containing from about 4 to about 30 carbon atoms and having a tertiary carbon atom attached to the nitrogen atom.

This application is a continuationin-part of our application Ser. No. 188,564 and a continuation-in-part of our application Ser. No. 188,580, each filed on Apr. 18, 1962, both now abandoned, and relates to the improvement of non-lubricating petroleum fractions such as distillate fuel oils containing additives adapted to inhibit sedimentation during prolonged storage periods, prevention of screenclogging, rusting of ferrous metal surfaces and, additionally, particularly in gasolines, to function as carburetor detergents and as inhibitors against objectionable emulsification.

It is well known that fuel oils are prone to form sludge or sediment during periods of prolonged storage. Such sediment has an adverse effect on burner operation, inasmuch as it has a tendency to clog screens and nozzles. In addition to sediment formed during storage, most fuel oils contain other impurities, such as rust, dirt and entrained water. The sediment and impurities tend to settle out on equipment parts such as nozzles, screens, filters, etc., thereby clogging them and causing failure of equipment. Furthermore, particularly as in the case of gasolines, there exists a tendency for these fuel oil compositions to form objectionable emulsions.

A factor, incident to the storage and handling of distillate fuels, i.e., gasoline and fuel oils, is the breathing of storage vessels. This results in the accumulation of considerable amounts of water in the tanks, which presents a problem of rusting. Thereafter, when the fuel is removed for transportation, a sufi'lcient quantity of water may be carried along which will cause rusting of ferrous metal surfaces in pipelines, tankers, and the like.

Heretofore, in the case of such fuel oil compositions, it has been the practice to overcome the aforementioned ditliculties by employing a separate additive for each purpose, i.e., a sediment inhibitor, an anti-screen clogging agent, an anti-rust agent and an emulsion inhibitor. The use of several such additives, however, gives rise to problems of additive compatability, thus restricting the choice of additive combinations. Furthermore, the use of a plurality of additives, unduly increases the cost of the fuel.

It is, therefore, an object of the present invention to provide distillate fuel oils having improved properties.

Another object of the invention is to provide distillate fuel oils containing a single additive, which is adapted to prevent screen clogging, rusting of ferrous metal surfaces with which it comes in contact, and to inhibit sedimentation and emulsification.

Other objects and advantages inherent in the invention will become apparent to those skilled in the art from the following detailed description.

In accordance with the present invention there are provided new and improved distillate fuel oil compositions containing between about 0.5 and about 200 pounds per 1,000 barrels of fuel of a compound selected from the group consisting of:

(a) RNHCH CH COOH and (b) CHzCHzC O OH CHzCHzC O OH wherein R is an alkyl group containing from about four to about thirty carbon atoms and having a tertiary carbon atom attached to the nitrogen atom. Such compounds can be prepared, for example, by reacting one mole of glacial acrylic acid at form about 50 C. to about 200 C. with one mole of a primary alkyl amine containing from about four to about thirty carbon atoms, and having a tertiary carbon atom attached to the nitrogen atom to form compound (a); and by reacting two moles of glacial acrylic acid with one mole of such a primary alkyl amine at the stated temperatures to form compound (b).

Amines utilizable for forming the aforesaid products are alkyl amines having between about 4 and about 30 carbon atoms per molecule, or mixtures of such amines, in which the amino (-NH group is attached to a tertiary carbon atom. These amines all contain the terminal group,

Non-limiting examples of such amine reactants are t-butyl primary amine, t-octyl primary amine, t-decyl primary amine, t-dodecyl primary amine, t-tetradecyl primary amine, t-octadecyl primary amine, t-eicosyl primary amine, t-docosyl primary amine, t-tetracosyl primary amine, and t-triacontyl primary aminefThe amine reactants can be prepared in several ways well known to those skilled in the art. Specific methods of preparing the t-alkyl primary amines are disclosed in the Journal of Organic Chemistry, vol. 20, page 295 et seq. (1955). Mixtures of such amines can be made from a polyolefin fraction (e.g., polypropylene and polybutylene cuts) by first hydrating with sulfuric acid and water to the corresponding alcohol, converting the alcohol to alkyl chloride with dry hydrogen chloride, and finally condensing the chloride with ammonia, under pressure, to produce a t-alkyl primary amine mixture.

Further specific examples of the aforementioned t-alkyl primary amines include a mixture of primary amines having a tertiary carbon atom of a tertiary alkyl group attached to the amino (NH and containing between about 12 and about 15 carbon atoms per molecule and averaging about 12 carbon atoms per molecule and containing, by weight, about percent t-dodecyl primary amine, about 10 percent t-pentadecyl primary amine, and relatively small amounts, i.e., less than 5 percent of amines having less than 12 or more than 15 carbon atoms; a mixture of tertiary alkyl primary amines containing from about 18 to about 24 carbon atoms per molecule, having a tertiary carbon atom attached to the (NH group, and containing, by weight, about 40 percent t-octadecyl primary amine, about 30 percent t-eicosyl primary amine, about 15 percent t-docosyl primary amine, about 10 percent t-tetracosyl primary amine and a small amount, less than 5 percent, of other amines.

The distillate fuels that are improved in accordance with the present invention, are distillate fuel oils which comprise hydrocarbon fractions having an initial boiling point of at least about 75 F. and an end boiling point not higher than about 750 F., and boiling substantially continuously throughout their distillation range. Such fuel oils are generally designated as distillate fuel oils. Of particular significance, within this range, is the treatment of petroleum distillate fuel oils, such as gasolines, comprising mixtures of hydrocarbons having an initial boiling point from about 75 F. to about 135 F. and an end boiling point from about 250 F. to about 450 F. It should be noted in this respect, that the term distillate fuel oils is not intended to be restricted to straight-run distillate fractions. These distillate fuel oils, can be straight-run distillate fuel oils, catalytically or thermally cracked (including hydrocracked) distillate fuel oils, or mixtures of straight-run distillate fuel oils, naphthas and the like, with cracked distillate stocks. Moreover, such fuel oils can be treated in accordance with well known commercial methods, such as acid or caustic treatment, hydrogenation, solvent-refining, clay treatment, and the like.

The distillate fuel oils are principally characterized by their distillation range. As hereinbefore indicated, this range will lie between about 75 F. to about 750 F. Obviously, the distillation range of each individual fuel oil will have a narrower boiling range falling, nevertheless, within the above-indicated limits. Likewise, each fuel oil will boil substantially continuously throughout its distillation range.

Particularly contemplated among the fuel oils are Nos. 1, 2, and '3 fuel oils used in heating and as diesel fuel oils, gasoline and the jet combustion fuels. The domestic fuel oils generally conform to the specifications set forth in AST M Specification D39648T. Specifications for diesel fuels are defined in ASTM Specification D975-48T. Typical jet fuels are defined in Military Specification MIL F-5624B. In addition, hydrocarbon lubricating oils of varying viscosities and pour-points, falling both within and outside the indicated ranges for the aforementioned fuel oils, may also be effectively treated throughout the use of the aforementioned additives. It will be understood, furthermore, that the additives of the present invention may be employed in any of the aforementioned distillate fuel oil compositions along with other additives intended to impart other improved properties thereto. Thus, as for example, in the case of gasolines, various anti-knock agents, pre-ignition inhibitors, metal-deactivators, dyes,

anti-oxidants, etc., may also be present. Furthermore, par- 1 ticularly in the case of gasolines, there may also be present small amounts, e.g. from about 0.01 percent to about 1 percent of a solvent oil or upperlube. Suitable oils for this purpose, may include Coastal and Mid-Continent distillate oils having viscosities within the range of from about 50 to about 500 S.U.S. at 100 F. Furthermore, synthetic oils, such as diester oils, polyalkylene glycols, silicones, phosphate esters, polypropylenes, polybutylenes, and the like, may also be used.

The amount of the additive embodied for use herein which is added to the distillate fuel oils, will depend, of course, upon the intended purpose and the nature of the particular additive selected, inasmuch as these additives are not all equivalent in their activity. Some of these additives may have to 'be employed in greater concentrations than others to be effective. In most cases, in which it is desired to obtain all of the aforesaid beneficial results in a fuel oil, namely, to inhibit sedimentation and emulsification, and to reduce screen clogging and prevent rusting of ferrous metal surfaces, additive concentrations, as previously indicated, will generally vary between about 0.5 to about 200 pounds per 1,000 barrels of oil. Preferably, however, these additives are employed in amounts varying between about 10 and about 200 pounds per 1,000 barrels of oil. In the case of gasolines, additives present in amounts from about 10 to about pounds per 1,000 barrels of gasoline are preferred.

The following specific examples will serve to illustrate the distillate fuel oil compositions of the present invention, and to exemplify the specific nature thereof. Included in such examples, is the preparation of compounds embodied for use in the practice of this invention, their use in various types of fuel oil compositions, and for purposes of comparison, the use of related products, but devoid of the aforementioned tertiary carbon atoms group as previously described. As is evidenced from the data hereinafter set forth, the additive products employed for use herein, markedly inhibit emulsification, in addition to imparting the other aforementioned desirable properties, as previously described, whereas related condensation products devoid of the aforementioned tertiary alkyl group, provide fuel oils that emulsify severely. It will be understood, however, that it is not intended that the invention be limited to the particular compositions shown, or to the operations or manipulations involved. Various modifications thereof, as previously described, can be employed and will be readily apparent to those skilled in the art.

The amine reactants employed in the following examples for reaction with acrylic acid, were as follows: Amine A is a mixture of primary amines having a carbon atom of a tertiary butyl group attached to the amino (NH group and containing from about 18 to about 24 carbon atoms. This material is manufactured by Rohm & Haas Company, under the trade name Primene JMT. Amine B is commercially available oleyl amine.

EXAMPLE 1 A mixture of 303 grams (one mole) of Amine A and 72 grams (one mole) of glacial acrylic acid were stirred at C. for about 2 hours and at C. for about one hour to produce the N-tertiary alkyl beta-amino propionic acid; i.e., the compound of Formula a.

EXAMPLE 2 A mixture of 144 grams (two moles) of glacial acrylic acid and 303 grams (one mole) of Amine A, was stirred at 135 C. for about two hours and at C. for one hour to produce the N-t-alkyl beta-amino dipropionic acid; i.e., the compound of Formula b.

EXAMPLE 3 A mixture of 72 grams (one mole) of glacial acrylic acid and 300 grams (1.0 mole) of oleylamine was stirred at 110 C. for about 4 hours to produce N-oleyl beta amino propionic acid.

Sedimentation The test used to determine the sedimentation characteristics of fuel oils is the 110 F. Storage Test. In this test, a 500-milliliter sample of the fuel oil under test is placed in a convected oven maintained at 110 F. for a period of 12 weeks. Then, the sample is removed from the oven and cooled. The cooled sample is filtered through a tarred asbestos filter (Gooch crucible) to remove insol uble matter. The weight of such matter in milligrams is reported as the amount of sediment. A sample of the blank, uninhibited oil is run along with a fuel oil blend under test. The effectiveness of a fuel oil containing an inhibitor is determined by comparing the weight of sediment formed in the inhibited oil with that formed in the uninhibited oil.

EXAMPLE 4 The additives described in Examples 1 and 2 were blended in portions of a test fuel oil and the blends were subjected to the 110 F. Storage Test. The test results comparing the blended fuels and uninhibited fuels are set forth in Table I. The test fuel oil is a blend of 60 percent distillate stock obtained from continuous catalytic cracking and 40 percent straight-run distillate stock. It has a boiling range of between about 320 F. and about 700 F.

Screen clogging The anti-screen clogging characteristics of a fuel oil were determined as follows: The test is conducted using a Sundstrand V3 or S1 home fuel oil burner pump with a self-contained 100-mesh Monel metal screen. About 0.05 percent, by weight, of naturally-formed fuel oil sediment, composed of fuel oil, water, dirt, rust, and organic sludge is mixed with 10 liters of the fuel oil. This mixture is circulated by the pump through the screen for 6 hours. Then, the sludge deposit on the screen is washed off with normal pentane and filtered through a tarred Gooch cucible. After drying, the material in Gooch crucible is washed with a 50-50 (volume) acetonemethanol mixture. The total organic sediment is obtained by evaporating the pentane and the acetone-methanol filtrates. Drying and weighing the Gooch crucible yields the amount of inorganic sediment. The sum of the organic and inorganic deposits on the screen can be reported in milligrams recovered or converted into percent screen clogging.

EXAMPLE Using the test fuel oil described in Example 4, blends of the additives of Examples 1 and 2 in this fuel were prepared. Each blend was subjected to the Screen Clogging Test, as aforedescribed. Test results are set forth in Table 11.

TABLE II.SCREEN CLOGGING Rust test in fuel oil The rusting characteristics of fuel oils were determined in the Static Rust Test, which simulates conditions encountered in storage vessels, such as, the home fuel storage tank. In this test, a strip of 16-20 gauge sand blasted steel plate is placed in a clear quart bottle. The length of the strip is sufficient to reach from the bottom of the bottle into the neck of the bottle without interfering with the cap. One hundred cc. of synthetic sea water with pH adjusted to 5 (ASTM D-665) and 750 cc. of test oil are placed in the bottle. The bottle is capped tightly, shaken vigorously for one minute, and permitted to stand quietly at 80 F. for 21 days. At the end of that time the amount of rust that occurs on the surface of the plate immersed in the water is used as a measure of the effectiveness of the fuel to inhibit rusting in storage vessels. It is generally preferred that no more than 5 percent of the surface should be rusted. This test is much more severe than the ASTM Rust Test. Many compositions that pass the ASTM test fail in the Static Test.

EXAMPLE 6 Blends of the additives described in Examples 1 and 2, in portions of the fuel oil defined in Example 4, were prepared. Each blend was subjected to the Static Rust Test. Pertinent data are set forth in Table III.

TABLE TIL-STATIC RUST TEST In reference to inhibiting emulsification, it has been found that products similar to those embodied for use herein but which do not contain a tertiary carbon atom group as aforedescribed do not inhibit emulsification whereas the products from the defined t-carbon atom containing products (Examples 1 and 2) markedly inhibit emulsification. To illustrate such a function performed by the additives useful for practice of this invention, the products of Examples 1 and 2 were individually blended with a distillate fuel oil in concentrations of 25, 50, and lbs/thousand barrels of the fuel oil and subjected to the following emulsion test, said fuel comprising 60% catalytically cracked components and 40% straight-run components and boiling in the range of 320640 F.

Emulsion test The procedure for the fuel oil emulsion test is as follows: a 200 milliliter portion of the fuel to be tested and 20 milliliters of distilled water are placed in a clear glass pint bottle. The bottle is tightly capped and set in an Ever-bach mechanical shaker in a horizontal position such that the maximum degree of agitation is afforded. The shaker is run at its maximum setting for 5 minutes. The botle is then removed, and allowed to stand in an upright position in the dark for 24 hours. At the end of the 24 hour settling period, the appearance of the water layer is noted. The fuel layer is siphoned oif, care being taken not to disturb the oil-water interface, and is discarded. A fresh portion of the fuel oil being tested is then added. The described sequence of steps is repeated. If no emulsion appears in the water layer after this sequence has been performed ten times, the oil is considered to have passed the test. On the other hand, if, after any 24 hour settling period in the procedure, there is any degree of emulsification in the water layer, the fuel is considered to have failed the test. This test procedure has been found to provide emulsions in inhibited oils similar to emulsions which occur in these same oils only after prolonged period of normal handling and storage in the field on a commercial basis.

Rating scale for reporting emulsion test results Rating: Description of emulsion 0 Clean break on the interface of oil and water.

No dirt, skin, or bubbles present.

1 Very slight skin at the oil-water interface that usually does not break on tilting the bottle.

2 Skin at oil-water interface, heavier than #1 and usually accompanied with dirt and bubbles on the skin. No evidence of any white emulsion.

3 First sign of white emulsion. Usually forms at the bottom and in the center of the bottle. It is circular in shape and approximately to 1 inch in diameter.

4 Approximately the same amount of emulsion on the bottom of the bottle as #3. However, emulsion is also beginning to form at oil-water interface and extends to downward into the water layer. Roughly 15% of water layer occupied by emulsion.

5 Circular emulsion at bottom of bottle extends outward and upward resembling spokes. Emulsion at the interface a little thicker than #4.

6 More emulsion than #5. Thin film of emulsion forming on sides of bottle surrounding the water layer. Water is still visible looking through the sides and looking up from the bottom of the bottle.

7 Emulsion on bottom of water layer is almost solid. Emulsion on sides of bottle is broken in a few spots enabling the operator to see the water layer.

Rating scale for reporting emulsion test results (Cont) Rating: Description of Emulsion 8 Semi-solid emulsion with perforations or bubbles similar to a honeycomb. No water visible except that seen in the bubbles.

9 Same emulsion as #8 but with less bubbles.

7590% emulsion is solid.

10 Almost completely solid emulsion with only a few air bubbles visible.

ll Completely solid emulsion (mayonnaise type).

The results obtained from the foregoing emulsion test were as follows:

Cone. of additive, Rating lbs/1,000 bbls.

Base fuel Example 1 25 2 Do 50 2 Base fuel Example 25 1 50 2 Base fuel Example 3 25 11 o 50 11 EXAMPLE 7 Anti-Rust Test-ASTM Rust Test D-665 Concn. of Rust test Inhibitor inhibitor, results parts/million Gasoline* None 0 Fail. Do Example Pass. Do Example 2.. 10 Do.

*100% catalytically cracked components, boiling range of 100400 F.

Carburetor detergency test The deposit-forming tendencies of a fuel are determined in an 8-hour engine test. This accelerated test, when run on fuels that contain no detergents, produces an amount of deposit equivalent to the amount observed in 4,000 miles of operation in field tests on taxicab fleets. A six-cylinder Chevrolet engine is equipped with notched rings to increase the amount of blowby. The engine is operated for eight hours, using the fuel under test, at alternated idle and running cycles. In the idle cycle, the engine is run at idling speed of 400 rpm. with no load, for five minutes. Then, for one minute, the engine is run at a speed of 2500 r.p. m., under a load of 30 B.H.P. and

at 9.4 in. mercury manifold pressure. During the running cycle, the blowby and exhaust are released into the carburetor air intake during the idling cycle. After 8 hours operation at alternate run and idle, the carburetor is examined and rated as to the amount of deposit in the throttle throat. In the rating scale, a rating of 0 (zero) indicates a clean carburetor; l=trace deposits; 2=light deposits; 3=medium deposits; and 4=heavy deposits.

EXAMPLE 8 Carburetor detergency test results *100% catalytically cracked components, boiling range of 100400 F.

Anti-stall test A standard Chevrolet engine, equipped with a Holley single downdraft carburetor, was mounted in a cold chamber refrigerated to about 40 F. A thermocouple was attached to the throttle plate shaft to record the plate temperature. A /2-inch insulating gasket was placed between the carburetor and manifold to prevent heat conduction. An asbestos sheet covered the entire manifold system to shield the carburetor from convection and radiation. A spray chamber was used to saturate the incoming air with moisture before entering an ice tower which cooled the air to about C.

In conducting a test, the engine was first run for about 10 minutes at 2000 r.p.m. to bring the engine temperature to equilibrium. The engine was then shut off. When the throttle shaft temperature rose to F., the engine was restarted with the idle speed set at 450 r.p.m. so that the base fuel stalled at idle in 10 seconds or less after a runtime of 20 to seconds. Run-time means the time that the engine was run at 2000 rpm. before returning to idle.

All the runs were started when the throttle shaft reached 40 F. At the instant of starting, the throttle arm was moved to the 2000 r.p.m. position and a stop watch started. At the end of the selected run-time, the throttle arm was moved to the idle position. The time required to stall was recorded. Several tests were made at each runtime and averaged. Any improvement caused by the additive was reflected in a longer run-time (as compared to the base fuel) to cause stalling in 10 seconds or less when the engine was idled. The more effective the additive, the longer the run-time.

EXAMPLE 9 Anti-Stall Test; Results Cone, lbs./ Run time to Additive 1,000 bbls. 10 sec. stall time (see) Gasoline None 0 Do Example 1 25 130 catalytically cracked components, boiling range of 100-400 F.

EXAMPLE 10 In order to further illustrate the importance of the presence of the aforementioned tertiary carbon atom in the group represented by R in the additives employed in the compositions of the present invention, a further comparison was made between the addition agents having a tertiary carbon atom (derived from a tertiary alkyl amine, designated hereinbefore as amine A) and a conventional type of related amine, in which no tertiary carbon atom was present, and which was derived from a commercially available straight-chain amine, viz. n-octadecyl amine.

For the purposes of such comparison, a mixture of 275 grams (one mole) of n-octadecyl amine and 72 grams (one mole) of glacial acrylic acid was stirred at 100 C.

for about five hours to produce the N-octadecyl betaamino propionic acid, in which no tertiary carbon atom, as previously discussed, was present.

The N-octadecyl beta-amino propionic acid, thus produced and samples of the additives prepared in accordance with Examples 1 and 2, were individually blended in a gasoline comprising 100 percent catalytically cracked components, boiling within the range from about 100 F. to about 400 F., at concentrations of 50 pounds per 1,000 barrels, and subjected to the aforementioned fuel oil emulsion test. The results of the aforementioned individual tests revealed that the sample containing the N-octadecyl beta-amino propionic acid formed a heavy emulsion upon the first contact with water, rendering it unsuitable for use as a fuel oil additive. On the other hand, the samples containing the additives of Examples 1 and 2 in which the aforementioned tertiary carbon atom was present, were found to form no emulsions, even after ten contacts.

Although the present invention has been described with preferred embodiments, it will be understood that various modifications and adaptations thereof may be resorted to without departing from the spirit and scope of the invention.

We claim:

1. A petroleum distillate fuel containing from about 0.5 to about 200 pounds per 1,000 barrels of fuel, a compound of the group consisting of:

(a) R-NHCHgCHgCOOH and (b) CHzCHzC O OH RO CHzxCH2C O OH wherein R is an alkyl group containing from about 4 to about 30 carbon atoms and having a tertiary carbon atom attached to the nitrogen atom.

2. A fuel as defined in claim 1 wherein R contains from about 18 to about 24 carbon atoms.

3. A fuel as defined in claim 1 wherein said fuel has an initial boiling point of at least about 75 F. and an end boiling point not higher than about 75 0 F.

4. A fuel as defined in claim 1 wherein said fuel corn- 5 prises a gasoline.

5. A fuel as defined in claim 1 wherein said fuel comprises a jet fuel.

6. A fuel as defined in claim 1 wherein said fuel comprises a diesel fuel.

References Cited UNITED STATES PATENTS DANIEL E. WYMAN, Primary Examiner.

Y. H. SMITH, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,418,092 December 24, 1968 Harry J. Andress, Jr., et al.

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 17, "form" should read from Column 9 lines 10 to 14, the formula should appear as shown below:

/CH CH COOH R-N\ CH CH COOH Signed and sealed this 17th day of March 1970.

(SEAL) Attest:

WILLIAM E. SCHUYLER, IR.

Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer