Synergistic mixture

Abstract

A synergistic mixture comprising from 1 to 99.9% by weight of compounds having structural elements (I) ##STR00001##
in which the free valencies on the oxygen atom and on the nitrogen atom may be combined to form a five-, six- or seven-membered ring and the benzene ring may also bear substituents at one or more of the free positions, and from 0.1 to 99% by weight of sulfur-containing organic compounds with antioxidant action. This synergistic mixture is suitable as a stabilizer for stabilizing inanimate organic material, especially mineral oil products and fuels, against the action of light, oxygen and heat.

Claims

1. A turbine or jet fuel selected from the group consisting of Jet Fuel A, Jet Fuel A-1, Jet Fuel B, Jet Fuel JP-4, JP-5, JP-7, JP-8 and JP-8+100, Jet A and Jet A-1, comprising 12 to 480 mg/L relative to a total weight of the fuel of a mixture of components (A) and (B) comprising (A) from 65 to 90% by weight of the mixture of (A) and (B) of at least one compound having at least one polycyclic phenolic compound of the following formula ##STR00021## (B) from 10 to 35% by weight of the mixture of (A) and (B) of at least one of a hydroxyl-containing diaryl sulfide, a reaction product of polyisobutene with thiophenol, and a reaction product of polyisobutenes with elemental sulfur, where the sum of the two components (A) and (B) adds up to 100% by weight.

2. A method of improving thermal stability of a turbine or jet fuel selected from the group consisting of Jet Fuel A, Jet Fuel A-1, Jet Fuel B, Jet Fuel JP-4, JP-5, JP-7, JP-8 and JP-8+100, Jet A and Jet A-1, the method comprising combining the fuel with a stabilizer comprising 12 to 480 mg/L of a mixture of components (A) and (B) comprising (A) from 65 to 90% by weight of the mixture of (A) and (B) of at least one compound having at least one polycyclic phenolic compound of the following formula ##STR00022## (B) from 10 to 35% by weight of the mixture of (A) and (B) of at least one of a hydroxyl-containing diaryl sulfide, a reaction product of polyisobutene with thiophenol, and a reaction product of polyisobutenes with elemental sulfur, where the sum of the two components (A) and (B) adds up to 100% by weight.

3. A method of reducing deposits in a fuel system or combustion system of a turbine, the method combusting a turbine or jet fuel selected from the group consisting of Jet Fuel A, Jet Fuel A-1, Jet Fuel B, Jet Fuel JP-4, JP-5, JP-7, JP-8 and JP-8+100, Jet A and Jet A-1, the method comprising 12 to 480 mg/L of a mixture of components (A) and (B) comprising (A) from 65 to 90% by weight of the mixture of (A) and (B) of at least one compound having at least one polycyclic phenolic compound of the following formula ##STR00023## (B) from 10 to 35% by weight of the mixture of (A) and (B) of at least one of a hydroxyl-containing diaryl sulfide, a reaction product of polyisobutene with thiophenol, and a reaction product of polyisobutenes with elemental sulfur, where the sum of the two components (A) and (B) adds up to 100% by weight.

4. The fuel of claim 1, wherein (A) is (XXXa) R.sup.19=methyl, R.sup.20=R.sup.22=H, R.sup.27=PIB.

5. The fuel of claim 1, wherein (A) is (XXXb) R.sup.19=methyl, R.sup.20=R.sup.22=tert-butyl, R.sup.27=PIB.

6. The fuel of claim 1, wherein (A) is (XXXc) R.sup.19=methyl, R.sup.20=tert-butyl, R.sup.22=methyl, R.sup.27=PIB.

7. The fuel of claim 1, wherein (A) is (XXXd) R.sup.19=R.sup.20=methyl, R.sup.22=tert-butyl, R.sup.27=PIB.

8. The fuel of claim 1, wherein (A) is (XXXe) R.sup.19=3-(dimethylamino)propyl, R.sup.20=R.sup.22=tert-butyl, R.sup.27=PIB.

9. The fuel of claim 1, wherein (A) is (XXXf) R.sup.19=PIB, R.sup.20=R.sup.22=R.sup.27=H.

10. The fuel of claim 1, wherein (A) is (XXXg) R.sup.19=PIB, R.sup.20=R.sup.22=H, R.sup.27=tert-butyl.

11. The fuel of claim 1, wherein (A) is (XXXh) R.sup.19=PIB, R.sup.20=R.sup.22=tert-butyl, R.sup.27=H.

12. The fuel of claim 1, wherein (A) is (XXXi) R.sup.19=PIB, R.sup.20=H, R.sup.22=R.sup.27=tert-butyl.

13. The fuel of claim 1, wherein (A) is (XXXj) R.sup.19=PIB, R.sup.20=R.sup.22=R.sup.27=tert-butyl.

14. The fuel of claim 1, wherein (A) is (XXXk) R.sup.19=PIB, R.sup.20=R.sup.22=H, R.sup.27=PIB.

15. The fuel of claim 1, wherein (B) is a hydroxyl-containing diaryl sulfide.

16. The fuel of claim 1, wherein (B) is a reaction product of polyisobutene with thiophenol.

17. The fuel of claim 1, wherein (B) is a reaction product of polyisobutenes with elemental sulfur.

Description

PREPARATION EXAMPLES

(1) The following compounds were used as component (A) in the inventive synergistic mixture: (A1) 2-aminomethyl-4-polyisobutyl-6-tert-butylphenol of the general formula II (R.sup.2=tert-butyl, R.sup.6=R.sup.7=hydrogen, M.sub.n of the polyisobutyl radical=1000), prepared according to the teaching of document (1) by alkylating 2-tert-butylphenol with polyisobutene and subsequent reaction with formaldehyde and ammonia; if, instead of 2-aminomethyl-4-polyisobutyl-6-tert-butylphenol, 2-(N,N-dimethylaminomethyl)-4-polyisobutyl-6-tert-butylphenol (R.sup.2=tert-butyl, R.sup.6=R.sup.7=methyl, M.sub.n of the polyisobutyl radical=1000), which is obtainable in an analogous manner by alkylating 2-tert-butylphenol with polyisobutene and subsequent reaction with formaldehyde and dimethylamine, is used, the same results are achieved in the application examples adduced below (A2) polyisobutyl-substituted tetrahydrobenzoxazine of the formula Vb, prepared according to the teaching of document (4) (A3) polycyclic phenolic compound having 3 benzene rings of the formula XXXc, prepared according to the preparation example adduced below

Preparation Example for A3

(2) A 500 ml four-neck flask was initially charged with 120 g of 4-polyisobutenylphenol, prepared from polyisobutene having a number-average molecular weight M.sub.n of 1000 and a content of terminal vinylidene double bonds of 80 mol % (Glissopal 1000 from BASF Aktiengesellschaft), at room temperature in 100 ml of toluene, and 48 g of the tetrahydrobenzoxazine of the general formula Vg were added within 15 minutes. The flask contents were heated to reflux and stirred under reflux for 2 hours. After cooling to room temperature, the mixture was washed with methanol and the toluene phase was concentrated under reduced pressure (5 mbar) at 150 C. 113 g of a clear, light-colored, viscous oil were obtained.

(3) .sup.1H NMR (400 MHz, 16 scans, CDCl.sub.3):

(4) =3.8-3.5 ppm (benzyl protons), =2.6-2.0 ppm (methylamine protons), =6.9-7.2 ppm (aromatic protons)

(5) The following sulfur-containing organic compounds were used as component (B) in the inventive synergistic mixture: (B1) 4,4-thiobis(2-tert-butyl-6-methylphenol), commercially available product; if, instead of 4,4-thiobis(2-tert-butyl-6-methylphenol), the likewise commercially available structural isomer 4,4-thiobis(2-tert-butyl-5-methylphenol) is used, the same results are obtained in the application examples adduced below (B2) phenyl polyisobutyl sulfide, prepared by the preparation example given below for B2 (B3) reaction product of polyisobutene with elemental sulfur to give polyisobutyl-substituted sulfur-containing five-membered heterocyclic rings, prepared by the preparation example given below for B3

Preparation Example for B2

(6) A 2 liter four-neck flask was initially charged with 90 g of thiophenol under an argon protective gas atmosphere. 7 g of boron trifluoride phenolate were added rapidly at room temperature. A solution of 800 g of polyisobutene having a number-average molecular weight M.sub.n of 1000 and a content of terminal vinylidene double bonds of 80 mol % (Glissopal 1000 from BASF Aktiengesellschaft) in 400 ml of hexane was added dropwise at 20 C. with cooling within 24 hours. After the addition had ended, the mixture was stirred at room temperature for another 3 hours. For workup, 250 ml of methanol were added, and the hexane phase was diluted with further hexane and washed twice more with 500 ml of methanol each time. After the hexane had been distilled off under reduced pressure (5 mbar) at 120 C., 846 g of phenyl polyisobutyl sulfide were obtained in the form of a light-colored oil.

(7) .sup.1H NMR (400 MHz, 16 scans, CDCl.sub.3):

(8) =7.51 ppm, 2H, aromatic protons; =7.32 ppm, 2H, aromatic protons; =1.78 ppm, 2H, polyisobutyl protons; further polyisobutyl protons

Preparation Example for B3

(9) 700 g of polyisobutene having a number-average molecular weight M.sub.n of 1000 and a content of terminal vinylidene double bonds of 80 mol % (Glissopal 1000 from BASF Aktiengesellschaft), together with 120 g of sulfur powder, were purged three times with nitrogen in a 2 liter laboratory autoclave at 100 C. Thereafter, with the aid of a metal bath, the mixture was heated to 220 C. for 1 hour and then to 240 C. for 1 hour. A needle valve was used to keep the internal pressure at 5 bar. Hydrogen sulfide which formed in the reaction and escaped via the needle valve was absorbed with chlorine bleach in a washing tower and decomposed. For workup, the mixture was diluted with 1000 ml of heptane, the solid was filtered off and the solution was concentrated under a rotary evaporator at 140 C. and 5 mbar. 750 g of product were obtained in the form of a brown oil which, according to .sup.1H NMR analysis, comprised, as main components, the two polyisobutyl-substituted five-membered sulfur heterocycles B3/I and B3/II shown below:

(10) ##STR00020##
(PIB** denotes the radical from the Glissopal 1000 used, shortened by one polyisobutene unit)

(11) .sup.1H NMR (400 MHz, 16 scans, CDCl.sub.3):

(12) B3/I: =8.21 ppm, 1H; =2.77 ppm, 2H

(13) B3/II: =2.44 ppm, 3H; =2.00 ppm, 2H; =1.58 ppm, 6H

(14) Inventive synergistic mixtures were prepared from components A1 to A3 in each case by mixing with components B1 to B3, and a portion thereof was used in the use examples which follow.

Use Examples

Example 1

Testing of the Thermal Stability of Turbine Fuel (Jet Fuel) by Determining the Amount of Particles Formed

(15) In each case, a commercial turbine fuel of the Jet A specification according to ASTM D 1655 was used. The additization was effected in each case with the amounts specified below of the mixtures or formulations M1 to M7 specified below, which comprised the components A1 to A3 and/or B1 or B2 specified above.

(16) TABLE-US-00001 M1 (for comparison) 40% by weight of A3, 10% by weight of 2,6-di-tert-butyl-4-methylphenol (BHT) (sulfur-free antioxidant), 4% by weight of commercial metal deactivator and 46% by weight of Solvent Naphtha Heavy (solvent) M2 (inventive) 40% by weight of A3, 8% by weight of B1, 10% by weight of 2,6-di-tert-butyl-4-methylphenol (BHT) (sulfur-free antioxidant), 4% by weight of commercial metal deactivator and 38% by weight of Solvent Naphtha Heavy (solvent) M3 (for comparison) 100% by weight of A1 M4 (for comparison) 100% by weight of B2 M5 (inventive) 50% by weight of A1 and 50% by weight of B2 M6 (inventive) 30% by weight of A2, 10% by weight of B1, 10% by weight of 2,6-di-tert-butyl-4-methylphenol (BHT) (sulfur-free antioxidant), 5% by weight of commercial metal deactivator, 30% by weight of Solvent Naphtha Heavy (solvent) and 15% by weight of 2-ethylhexanol (solvent) M7 (for comparison) 30% by weight of A2, 10% by weight of 2,6-di-tert-butyl-4-methylphenol (BHT) (sulfur-free antioxidant), 5% by weight of commercial metal deactivator, 30% by weight of Solvent Naphtha Heavy (solvent) and 25% by weight of 2-ethylhexanol (solvent)

(17) In a three-neck glass flask which had been equipped with stirrer, reflux condenser and thermometer, 5 l of air were initially passed through 150 ml of the fuel to be analyzed at room temperature within 1 h. Subsequently, the fuel was heated to 160 C. with an oil bath and stirred at this temperature for a further 5 h. After cooling to room temperature, the entire amount of fuel was filtered through a 0.45 m membrane filter. Subsequently, the filter residue, after drying in a drying cabinet at 115 C. for 45 min and subsequently drying under reduced pressure for 2 hours, was determined gravimetrically in a desiccator.

(18) Table 1 which follows shows the results of the gravimetric determinations:

(19) TABLE-US-00002 TABLE 1 Sample Fuel Dosage Result Blank value No. 1 0 11.0 mg M1 No. 1 250 mg/l 2.2 mg M2 No. 1 250 mg/l 1.4 mg Blank value No. 2 0 15.7 mg M3 No. 2 200 mg/l 13.2 mg M4 No. 2 200 mg/l 16.3 mg M5 No. 2 200 mg/l 9.7 mg Blank value No. 3 0 13.2 mg M6 No. 3 150 mg/l 3.0 mg M7 No. 3 150 mg/l 3.4 mg M6 No. 3 30 mg/l 7.8 mg M7 No. 3 30 mg/l 8.3 mg

(20) In all cases, the inventive mixtures or formulations provide significantly better results, i.e. smaller amounts of filter residue than the corresponding comparative samples. As a result of the use of the inventive synergistic mixture, it was thus possible to significantly reduce the amount of particles formed through thermal stress on the turbine fuel.

(21) The synergism between components (A) and (B) can be seen clearly, for example, by the result of samples M3, M4 and M5: B2 in M4 exhibits no antioxidant action whatsoever (the amount of particles is even increased compared to the blank value); when B2, which is ineffective per se, is mixed with A1, which is already moderately effective in M3, an unexpectedly high jump in the activity occurs once again.

Example 2

Testing of the Water Removal Properties from Turbine Fuel by Measuring the Opacity of the Fuel Phase

(22) A commercial turbine fuel (jet fuel) of the Jet A-1 specification according to DEF STAN 91-91 was used. The tendency of the turbine fuels with regard to their water removal properties was tested to ASTM D 3948 (MSEP test). What is characteristic of these measurements is the use of a standard coalescing filter with final opacity measurement of the fuel phase. In the measurement, the mixtures M8 to M10 specified below were tested, which comprised the above-specified components A1 to A3 and B1 in combination with the sulfur-free antioxidant 2,6-di-tert-butyl-4-methylphenol (BHT) and the metal deactivator N,N-disalicylidene-1,2-diaminopropane. The dosage of the mixture used was in each case 500 mg/l. Marks for the opacity behavior reported in table 2 below were determined [relative evaluation scale from 0 (worst mark) to 100 (best mark)].

(23) TABLE-US-00003 M8 30% by weight of A1, (inventive) 10% by weight of B1, 10% by weight of 2,6-di-tert-butyl-4-methylphenol (BHT), 5% by weight of N,N-disalicylidene-1,2-diaminopropane, 30% by weight of Solvent Naphtha Heavy (solvent) and 15% by weight of 2-ethylhexanol (solvent) M9 30% by weight of A2, (inventive) 10% by weight of B1, 10% by weight of 2,6-di-tert-butyl-4-methylphenol (BHT), 5% by weight of N,N-disalicylidene-1,2-diaminopropane, 30% by weight of Solvent Naphtha Heavy (solvent) and 15% by weight of 2-ethylhexanol (solvent) M10 30% by weight of A3, (inventive) 10% by weight of B1, 10% by weight of 2,6-di-tert-butyl-4-methylphenol (BHT), 5% by weight of N,N-disalicylidene-1,2-diaminopropane, 30% by weight of Solvent Naphtha Heavy (solvent) and 15% by weight of 2-ethylhexanol (solvent)

(24) TABLE-US-00004 TABLE 2 Sample Mark Blank value 100 M8 83 M9 100 M10 97

(25) Virtually no, if any, deteriorations in the water removal properties from turbine fuels compared to unadditized turbine fuel occur with mixtures M9 and M10, and slight but not disadvantageous deteriorations with mixture M8.

Example 3

Testing of the Thermal Stability of Turbine Fuel (Jet Fuel) by Determining the Breakpoint

(26) A commercial JP-8 turbine fuel according to MIL-DTL-83133E was used. The thermal stability was tested by the JFTOT breakpoint method to ASTM D 3241. For the turbine fuel not additized with the inventive synergistic mixture, a value of 290 C. was determined. With the same fuel additized with 250 mg/l of sample M10, a breakpoint of 340 C. was measured, and, for the same fuel additized with 1000 mg/L of sample M10, a breakpoint of 350 C. was measured.

Example 4

Testing of the Water Removal Properties of Turbine Fuel by Determining the Residual Water Content in the Fuel

(27) A commercial JP-8 turbine fuel according to MIL-DTL-83133E was used. For the determination of the residual water content in the fuel after the removal of water, a 5 liter vessel with an incorporated coalescence filter element was used. The fuel converted to an emulsion by intensive stirring in a reservoir with 1% by weight of water, for removal of water, was passed at 22 C. through the coalescence filter and the residual water content of the fuel phase was determined by means of Karl-Fischer titration. The less residual water in the fuel, the better are the water removal properties. This is because additives used in the turbine fuel typically worsen the water removal properties, for example in the case of use of coalescence filters.

(28) Commercial JP-8 turbine fuel according to MIL-DTL-83133E additized with customary antistats, corrosion inhibitors and antiwear additives and deicing agents in the customary amounts had, after emulsification and water removal by the above-described test method, a residual water content of 564 ppm by weight (comparative value). Unadditized commercial JP-8 turbine fuel according to MIL-DTL-83133E, which had been treated beforehand with alumina to remove the abovementioned additives, had, after emulsification and water removal by the above-described test method, a residual water content of 83 ppm by weight (blank value). The same turbine fuel addized with customary antistats, corrosion inhibitors or antiwear additives and deicers in the customary amounts, before performance of emulsification and water removal, was additionally admixed with 250 mg/I of sample M10 and had, at the end, a residual water content of 91 ppm by weight instead of 564 ppm by weight. The value of 91 ppm by weight achieved in accordance with the invention is thus within the order of magnitude of the blank value of 83 ppm by weight.

(29) While the presence of additives in turbine fuels normally brings about a significant deterioration in the water removal properties, i.e. an increase in the residual water content, residual water contents in the order of magnitude of unadditized turbine fuel occur when the inventive synergistic mixture is used. The addition of the inventive synergistic mixture even eliminates the adverse effect of additives already present on the water removal properties.