DE1280450B - Stabilized fuel oil based on hydrocarbons - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. CL:

ClOl

German class: 23 b -4/02

Number: 1280450

File number: P 12 80 450.1-44 (S 91239)

Filing date: May 26, 1964

Opening day: October 17, 1968

It is known that aircraft turbine engines or jet engines, especially in supersonic jets, operated at extremely high temperatures. To induce heat removal and also to preheat the entering fuel oils, the fuel or fuel oil becomes subjected to indirect heat exchange with the combustion chamber. If then that Incoming fuel oil flows through the introduction nozzles, it will continue to undergo relatively high temperature conditions exposed. It has been found that many jet fuels are relatively unstable when subjected to such high temperatures. Decomposition products are formed which the Dirt heat exchange tubes and clog the inlet nozzles. The usage Such fuel oils therefore lead to shortened operating times of the machine and can be a source of danger when operating jet aircraft.

It is known to add phenols, such as catechol, to fuels for stabilization. aside from that was the addition of unspecified phenolic substances by extraction or distillation from a distillate obtained by cracking tar, to one obtained by the Cracking fuel produced by tar is described. However, the known additives are not suitable To make fuel oils or fuels resistant to high temperatures.

The object of the invention is to provide stabilized fuel oils based on hydrocarbons, the are resistant at relatively high temperatures and do not suffer any thermal degradation, so that they can be used with particular advantage as jet fuel oils.

It has been found that thermally unstable hydrocarbon fuel oils or fuels and particularly petroleum hydrocarbon distillate fuel oils for jet engines in a simple, effective manner and technically advantageous manner by adding a straight-chain polyalkylated catechol are stabilized against degradation or decomposition with at least 6 carbon atoms per alkyl group can, so that when they are used in nozzle machines, the contamination of heat exchange tubes and nozzle clogging is minimized.

The stabilized fuel oil according to the invention based on hydrocarbons, especially petroleum distillate jet fuel oil, is characterized in that it

Stabilized fuel oil
Hydrocarbon base

Applicant:

Mobil Oil Corporation, New York, NY
(V. St. A.)

Representative:

Dr. E. Wiegand

and Dipl.-Ing. W. Niemann, patent attorneys,

8000 Munich 15, Nussbaumstr. 10

Named as inventor:

Harry John Andress Jr., Pitman, N. J .;

Paul Yoke Chan Gee, Woodbury, N. J. (V. St. A.)

Claimed priority:

V. St. v. America May 31, 1963 (284 319) - -

(1) a straight-chain polyalkylated catechol with at least 6 carbon atoms per alkyl group

and

(2) a polymeric acid

contains.
The polymeric acids serve as rust inhibitors and lubricity improvers.

The catechols used in the fuel oils according to the invention are in particular straight-chain polyalkylated catechols with 6 to about 30 carbon atoms per alkyl group and preferably straight-chain polyalkylated catechols with about 9 to 30 carbon atoms per alkyl group or straight-chain wax-alkylated catechols. It has been found that the alkylated with a relatively long straight chains catechols form particularly effective Düsentreibstoffstabilisiermittel at high temperatures, such as ^316-0 C. In contrast, it has been found that relatively short-chain and branched-chain alkylated catechols, such as tert-butyl catechols, diisopropyl catechols and tritetrapropyl catechols, showed no effectiveness as jet fuel stabilizers, but even worsened the jet fuel.
Relatively small amounts of the polyalkylated catechols are added to the hydrocarbon fuel oils in order to provide the desired protection against thermal degradation at relatively high levels

809 627/1168

3 4

Temperatures to reach. The desired effect of (1) a mixture of paraffins within the water is achieved by adding the polyalkylated benzene range of C ₁₀ or C ₁₁ and higher and (2) naphcatechol in the fuel oil in an amount of about ten. These compositions are from 0.0001 to about 1.0 weight percent based on that further characterized by having a net fuel oil incorporation. The fuel oil will have a heat of combustion of at least 480 kcal / kg moderately a mixture of straight-chain polyalkylated and contain no more than about 5 percent by volume of catechol with at least 6 carbon atoms per aromatic, essentially free of C ₉ and alkyl groups and the polymeric acid in one amount Lower paraffins are, and these paraffins are introduced in a concentration of about 0.01 to about 1.0 percent by weight, based on the concentration substantially above the naphthene concentration on the fuel oil, the weight ion containing the predominant amount being the ratio of catechol to polymeric Acid paraffins in the C ₁₁ - to C _le range. Composition can range between about 1: 1 and about 1: 100. tongues, a Luminometerzahl of at least about 100 The applicable polyalkylated catechols and maximum freezing points of about - 35 ⁰ C can easily have synthetically from catechol, are preferred. With regard to the aforementioned and a 1-olefin in the presence of various liquid fuel oils, compositions are catalysts, e.g. B. a boron fluoride catalyst, or preferably, which is at most about 35 volume percent of an alkyl halide and catechol, e.g. B. contained in naphthenes when the aromatic content is about the presence of a zinc chloride catalyst, prepared 5 percent by volume, and for each 1 percent by volume. * Reduction of the aromatic content to below 5 volume - The conversion between catechol and an ao percent decreases the maximum naphthene content olefin or alkyl halide is expedient at about 3 volume percent. Particularly suitable liquid temperature between about 75 and 220 ° C is carried out for compositions for use as nozzles to alkylate the catechol. Examples of fuels in combination with the additives suitable according alkylated catechols are: tri- the invention are those comprising about hexadecylbrenzcatechin, or 25,177 boiling in the range of Tetrahexylbrenzcatechin to about 288 ⁰ C and consisting essentially of different straight-chain wachsalkylierte Brenzcate- (1) a mixture of paraffins within the bechine. rich from C ₁₀ nd higher and (2) naphthenes, which are next to the. straight chain polyalkylated pyrites - these compositions being further catechins present as rust inhibitors and characterized in that they can (a) have a net burn lubricity improver polymeric acid heat of at least about 10 500 kcal / kg in the form of dimeric, trimeric or flash point of 65.6 ⁰ C (minimum) and a higher polymeric acids must be present. Have vapor pressure of about 3.5 g / cm ² (maximum) at Many of the commercially available dimer acids 260 ⁰ C, (b) no more than about 5 volume percent, for example, contain about 85% dimer acids aromatics contained and substantially free of C ₉ and about 12% trimeric and higher polymeric acids. 35 and deeper paraffins are and (c) paraffins contained within the second bubble residue of the dry distillation range of C ₁₀₊ in a concentration essential of castor oil in the presence of sodium Hch above the naphthene concentration, with hydroxyd containing z. B. about 45 to 50% dimeric acids, the predominant amount of paraffins in the C ₁₁ - bis and about 50% trimeric and higher polymeric acids. C _ie range is.

Preference is given to additional materials which are not than about 15% unpolymerized unsaturated fat - illustrating the manufacture of additives for contain acids and saturated fatty acids. The content of the fuel oil according to the invention and for Darder Materials on dimeric, trimeric and increased their effectiveness with regard to the thermal polymeric acids are said to preferably at least about stabilize hydrocarbon fuel oils 85%, with the dimer acids at least 45 and especially petroleum hydrocarbon distillates about 50% of the dimeric and higher polymeric acids are fuel oils for jet machines. For the manufacture showing. A more detailed description of the polymer development of the additives is within the scope of the invention Acids that do not claim any protection for use in fuel oils.

are suitable according to the invention is in the USA.- A wax catechol in which a lot

U.S. Patent 2,632,695. 50 chlorine wax (chlorinated paraffin), the 2 atomic proportions

Contains hydrocarbon distillate fuel oils for jet chlorine and has a chlorine content of 10 percent by weight machines, which are improved according to the invention, reacted with 1 mole of pyrocatechol can include hydrocarbon fractions with is, hereinafter referred to as "wax catechol 2-10" an initial boiling point of at least about 38 ° C. In a similar way, »Wax-Brenz- and a final boiling point of about 399 ° C. This 55 catechin 3-12 "and" wax pyrocatechin 4-12 "through Fuel oils can be straight-run distillate fractions, converting sufficient amounts of chlorinated catalytically or thermally cracked (including wax with a content of 12 percent by weight chlorine, hydrocracked) distillate fractions or mixtures of 3 atomic proportions or 4 atomic proportions of chlorine per mole to provide catechol from straight-run fuel oils or commercial petrol, with cracked distillate oils or alkylates. 60

Regulations, the typical special fuel oils working method

define are MIL-F-5616, MIL-J-5624D, MIL-F-

25656, MIL-F-2524A, MIL-F-25576A, MIL-F-25558B A mixture of 92 g (0.836 moles) catechol,

and MIL-J-5161E. 422 g (2.51 mol) propylene tetramer and 25 g boron fluorine

The most useful jet fuels made up of the present invention over a period of about 10 to 12 hours at a temperature between about 177 or 90 and about 95.degree. C. comprise liquid fuels stirred. approximately 100 g of water was 190 ° C boiling to about 288 ⁰ C and concentrated feels essentially of at this point to the Borfluoridkataly-

I 280 450

5 6

to destroy sator. The reaction mixture was procedure 7

then washed with hot water until the washing liquids running off are neutral to pH paper A mixture of 110 g (1 mol) of catechol, was. The end product, a tritetrapropyl pyranium 556 g (4 moles) of a mixed 1-olefin fraction (with catechin, was reduced by top distillation to a composition similar to that of the mixed tem pressure obtained at 240 ° C. 1-olefin fraction according to Example 6) and 35 g of boron tri

Fluoridäthylätherat was stirred at about 85 to about 90 ⁰ C, procedure 2 ^{for about} 10 hours. About 200 g of water

were added to the reaction mixture; latter

A mixture of 355 g (1 mol) of 10% chlorine wax, io was then washed with hot water until the 55 g (0.5 mol) of catechol and 41 g of anhydrous washing liquids were neutral to pH paper. Zinc chloride was slowly added in the course of time, The product, a Tetraalkylbrenzcatechin was heated chamber from about 12 hours to about 210 ⁰ C. by top distillation at 240 ° C. under reduced pressure. The reaction mixture was filtered and obtained under hot pressure.
Water washed until the washing liquids against 15 working method 8

pH paper were neutral. The end product, a wax

Catechol 2-10, was Topdestillation under it, a mixture was prepared, to get the 9.1 g Wachsverringertem pressure at 23O ⁰ C. Pyrocatechol 4-12, which is produced according to the procedure 4

was produced, and 90.9 g of technical dimeric acid procedure 3 ^a ° (about 85% dimeric acids and about 14% trimeric and

containing higher polymeric acids).

A mixture of 400 grams (1.36 moles) of 12% chlorine- Any of the products of the above procedures

wax, 50 g (0.454 mol) of catechol and 45 g of water was the conditions of a testing method under anhydrous zinc chloride was added slowly over worfen one oil the for determining the thermal resistant-period of about 12 hours to about 21O ⁰ C 35 speed of aircraft turbine fuel used heated. The reaction mixture was filtered and becomes. The method has been topped by the Coordinating at 24O ⁰ C under reduced pressure to develop a Research Council and is to be produced in the CRC wax catechol 3-12. Report »Investigation of Thermal Stability of Aviation

Turbine Fuels with CFR Fuel Coker «(CRC project

Working method 4 3 <> CFA-2-54) published in July 1957. The working

in detail in Annex XV of the »ASTM Standard

A mixture of 400 g (1.36 mol) of 12% Chlorards on Petroleum Products and Lubricants, Novemwax, 37.4 g (0.34 mol) of pyrocatechol and 44 g over 1957, beginning on p. 1059, are given. These anhydrous zinc chloride was added slowly over method provides a means for measuring the Hochvon about 12 hours to about 210 ⁰ C heated. The 35 temperature stability of aircraft turbine combustion reaction mixture was filtered and oiled at 265 ° C under fabric using a device known as reduced pressure, a wax-firing "CFR Fuel Coker", this will catechin 4-12 obtain. tested fuel oil temperatures and conditions

which are similar to the conditions found in certain aircraft turbine operation 5 40 machines.

The fuel oil is released at a rate of

A mixture of 110 g (1 mole) of pyrocatechol, about 2.72 kg / h through a preheater section-460 g (2 moles) of a mixture of straight chain pumps, which the hot fuel line sections 1-olefins, the 6% 1-dodecene, 14% 1-tetradecene, the machine, as typically found in a machine-42% 1-hexadecene, 33% 1-octadecene and 5% 1-45 fuel oil cooler, simulates or emulates. Eicosene and comprised an average molecular weight, the fuel oil is then passed through a heated FII-230 had, and 28 g Bortifluoridäthylätherat terabschnitt was stirred for which the nozzles or the narrow range about 12 hours at 90 ⁰ C. The reaction fuel oil passages of the hot portion of the mix have been filtered and exposed to hot water where fuel oil breakdown products are washed off until the wash fluids catch against pH 50 paper and can be deposited. One with high neutral were. The finished product, a dialkyl fiery precision sintered stainless steel filter in catechin, was obtained by top distillation under the heated filter section holding fuel oil degradation reduced pressure at 182 ° C. products made during the test,

return. The extent of the deposit is shown by working method 6 55 an increased pressure drop across the test filter and is, in

Combination with the separation state of the pre-

A mixture of 91 g (0.827 mol) pyrocatechol, heater, used as a parameter for the high temperature 344 g (2.48 mol) of a mixed 1-olefin fraction resistance of the fuel oils. In the test described here (1% 1-octene, 25% 1-nonene, 53% 1-decene, 21% 1-, the filter ^{temperature was 316 undecene; average molecular weight about 139) and 60 to 344 0} C, and the pipe temperature of the preheater 25 g Bortrifluoridäthylätherat was maintained at about 85 to 288 ⁰ C. amounted to case 260 each test sequence about 9O ⁰ C was stirred for about 8 hours. About 100 g of water continued the test until a pressure drop of 635 mm was added to the reaction mixture; the latter mercury was present on the filter or until one drained was then washed with hot water until the time of 300 minutes, whichever came first. Wash liquids were neutral to pH paper. 65 To the test to meet satisfactory one The product, a Trialkylbrenzcatechin should, has been demonstrated by fuel oil little or small pressure drop across the Topdestillation at 255 ⁰ C under reduced pressure filter at the end of 300 minutes. The reserve. Heat deposits are used in the tests after a

digit rating ranging from 0 to 8 is determined as shown in the table below; included A rating lower than Index 3 is desirable for an effectively persistent aircraft turbine fuel oil.

The underlying hydrocarbon jet fuel oil used in conjunction with the in the table A straight-run petroleum fraction with 100% isoparaffins was used in a boiling range from about 165 to 204 ° C. Parts of this basic fuel oil were not inhibited Subject to the state of the fuel oil coker test, then other proportions of the base fuel oil were included the reaction products of the preceding examples mixed, and any mixture thus obtained was subjected to the fuel oil coker test. Relevant mixing values and test results are in in the table below.

Inhibitor Conc J ¹ UtCr- before Filter ver Preheater separations Ver tration tcnipc- heater constipation at 300 minutes search rature tempe pressure No. non-inhibited nozzle burning g / m ⁸ ° c rature waste Key figure evaluation (KZ) fabric oil 316 ⁰ C mm Hg 55% KZ 1.30% KZ 5.15% KZ 7 1 non-inhibited nozzle burning 260 0.0 fabric oil 344 39% KZ 2, 8% KZ 4.15% KZ 7 2 Fuel oil + 3.5- 288 0.0 15% KZ 3, 8% KZ 5.15% KZ 8 Diisopropyl catechol 57 344 45% KZ 1.15% KZ 3.40% KZ 8 3 Fuel oil + 4-tert- 288 63.5 Butyl catechol 57 344 52% KZ2, 8% KZ 3.40% KZ 8 4th Fuel oil + catechol 288 7.6 of working method 1 57 316 67% KZ 2, 8% KZ 3.25% KZ 8 5 Fuel oil + catechol 260 0.0 of working method 2 57 316 100% concentration camp 2 6th Fuel oil + catechol 260 0.0 of working method 3 57 344 92% KZ 2, 2% KZ 3 7th Fuel oil + catechol 288 0.0 of working method 4 57 344 100% concentration camp 2 8th Fuel oil + catechol 288 0.0 of working method 5 57 344 70% KZ 2, 30% KZ 3 9 Fuel oil + catechol 288 0.0 of working method 6 57 344 - 100% concentration camp 2 10 Fuel oil + catechol 288 0.0 of working method 7 57 344 100% concentration camp 2 11 Fuel oil + catechol 288 0.0 of working method 8 314 316 100% concentration camp 2 12th 260 0.0

KZ1 = matting of the preheater,
KZ 2 = slight discoloration,
KZ 3 = light tan,
KZ 4 = medium tan,

From the above values in the table it can be seen that the uninhibited jet fuel oil (Experiments 1 and 2) and the fuel oils containing 3,5-diisopropylpyrocatechol and 4-tert-butylpyrocatechol and Tritetrapropylpenzcatechin contained (experiments 3, 4 and 5), unsatisfactory results with regard to of the preheater deposits (code number 4 to code number 8). The marked improvement that emerge from the application of the invention by using the straight-chain alkylated ones mentioned above Catechols with at least 6 carbon atoms per alkyl group as a fuel oil additive clearly work from the values of experiments 6 to 12. It can be seen that the fuel oils according to Invention met the requirements of the test, d. H. to the Mainly resulted in a code number 2 and showed no pressure drop on the filter after about 300 minutes.

KZ 5 = light brown,
KZ 6 = medium brown,
KZ 7 = dark brown,
KZ 8 = black.

Claims (1)

Claim: Stabilized hydrocarbon-based fuel oil, especially petroleum distillate nozzle fuel oil, characterized in that it (1) a straight-chain polyalkylated catechol with at least 6 carbon atoms per alkyl group and (2) a polymeric acid
contains. Considered publications: U.S. Patent Nos. 2,038,630, 2,052,859, 2 054 276, 2 104 049, 2123 083. 809 627/1168 10.68 © Bundesdruckerei Berlin