CORROSION INHIBITORS FOR FUELS AND LUBRICANTS

Abstract

The present invention relates to novel uses of corrosion inhibitors in fuels and lubricants.

Claims

1-13. (canceled)

14: A corrosion inhibitor, comprising: a copolymer obtained by a process comprising: copolymerizing (A) at least one ethylenically unsaturated mono- or dicarboxylic acid or a derivative thereof selected from the group consisting of an anhydride in a monomeric or a polymeric form, a mono- or alkyl ester, and a mixed ester, (B) at least one -olefin comprising from 16 to 28 carbon atoms, (C) optionally at least one aliphatic or cycloaliphatic olefin which comprises at least 4 carbon atoms and is different than (B), and (D) optionally at least one copolymerizable monomer other than (A), (B) and (C), which is selected from the group consisting of (Da) a vinyl ester, (Db) a vinyl ether, (Dc) a (meth)acrylic ester of an alcohol comprising at least 5 carbon atoms, (Dd) an allyl alcohol or ether thereof, (De) a N-vinyl compound selected from the group consisting of a vinyl compound of a heterocycle comprising at least one nitrogen atom, a N-vinylamide, and a N-vinyllactam, (Df) an ethylenically unsaturated aromatic, (Dg) an ,-ethylenically unsaturated nitrile, (Dh) a (meth)acrylamide, and (Di) an allylamine, thereby obtaining a first copolymer; and subsequently partly or fully hydrolyzing the anhydride or carboxylic ester functionalities present in the first copolymer until at least the first copolymer does not comprise any free carboxylic functionalities, thereby obtaining the copolymer, wherein the copolymer has a weight-average molecular weight Mw determined by permeation chromatography with tetrahydrofuran and polystyrene as standard of 1.5 to 4 kDa,

15: The corrosion inhibitor of claim 14, wherein (A) is at least one selected from the group consisting of acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, methyl methacrylate, and maleic anhydride.

16: The corrosion inhibitor of claim 14, wherein (A) is a dicarboxylic acid or a derivative thereof and is at least one selected from the group consisting of an anhydride in a monomeric or a polymeric form, a mono- or dialkyl ester, and a mixed ester.

17: The corrosion inhibitor of claim 14, wherein (B) is an -olefin comprising from 18 to 26 carbon atoms.

18: The corrosion inhibitor claim 14, wherein (C) is present during said copolymerizing and is a polymer comprising more than 30 carbon atoms of propene, 1-butene, 2-butene or isobutene, or an olefin mixture comprising the latter and having a weight-average molecular weight M.sub.w in the range of from 500 to 5000 g/mol.

19: The corrosion inhibitor of claim 14, wherein (C) is present during said copolymerizing, (C) is a polymer of isobutene or an olefin mixture comprising the latter, (C) has more than 30 carbon atoms, and (C) has a weight-average molecular weight M.sub.w of from 500 to 5000 g/mol.

20: The corrosion inhibitor of claim 14, wherein (C) is present during said copolymerizing, and an averaged molar amount of a mixture of (B) and (C) comprises at least 12 carbon atoms.

21: The corrosion inhibitor of claim 14, wherein (D) is present during said copolymerizing, and (D) is at least one selected from the group consisting of (Da), (Db), (Dc), (De) and (Df).

22: The corrosion inhibitor of claim 14, wherein (C) is present during said copolymerizing, and a molar ratio of (A)/[(B)+(C)] is from 10:1 to 1:10.

23: The corrosion inhibitor of to claim 22, wherein a molar ratio of (B) to (C) is from 1:0.05 to 10.

24: The corrosion inhibitor of claim 14, wherein (D) is present during said copolymerizing, and a proportion of (D), based on a total amount of (A), (B), and optionally (C), is from 5 to 200 mol %.

25: A fuel, comprising: at least one alkali metal and/or at least one alkaline earth metal and/or zinc in a total content of at least 0.1 ppm by weight; and the corrosion inhibitor of claim 14.

26: The fuel of claim 25, wherein the at least one alkali metal and/or the at least one alkaline earth metal are selected from the group consisting of sodium, magnesium, and calcium.

27: The fuel of claim 25, wherein the fuel is a diesel fuel or a gasoline fuel.

28: A method for inhibiting corrosion of an iron surface, a steel surface and/or a nonferrous metal surface, the method comprising: applying the corrosion inhibitor of claim 14 to the iron surface, the steel surface and/or the nonferrous metal surface.

29: The method of claim 26, wherein the nonferrous metal is a copper or a copper-containing alloy.

Description

EXAMPLES

GPC Analysis

[0208] Unless stated otherwise, the mass-average molecular weight Mw and number-average molecular weight Mn of the polymers was measured by means of gel permeation chromatography (GPC). GPC separation was effected by means of two PLge Mixed B columns (Agilent) in tetrahydrofuran at 35 C. Calibration was effected by means of a narrow-distribution polystyrene standard (from PSS, Germany) having a molecular weight of 162-50 400 Da. Hexylbenzene was used as a marker for low molecular weight.

Preparation Examples

General Procedure

[0209] A reactor having an anchor stirrer was initially charged with the olefin or the mixture of olefins with or without solvent (as a bulk polymerization). The mixture was heated to the temperature specified under a nitrogen stream and while stirring. To this were added the free-radical initiator specified (optionally diluted in the same solvent) and molten maleic anhydride (1 equivalent based on olefin monomer). The reaction mixture was stirred at the same temperature for the reaction time specified and then cooled down. Water was subsequently added (unless stated otherwise, 0.9 equivalent based on maleic anhydride) and the mixture was stirred either at 95 C. for 10-14 h or under pressure at 110 C. for 3 h.

Synthesis Example 1

[0210] A 2 L glass reactor having an anchor stirrer was initially charged with a mixture of C.sub.20-C.sub.24 olefins (363.2 g, average molar mass 296 g/mol) and Solvesso 150 (231.5 g, DHC Solvent Chemie GmbH, Speldorf). The mixture was heated to 160 C. in a nitrogen stream and while stirring. To this were added, within 5 h, a solution of di-tert-butyl peroxide (29.6 g, from Akzo Nobel) in Solvesso 150 (260.5 g) and molten maleic anhydride (120.3 g). The reaction mixture was stirred at 160 C. for 1 h and then cooled down to 95 C. At this temperature, water (19.9 g) was added within 3 h and the mixture was then stirred for a further 11 h.

[0211] GPC (in THF) gave an Mn=1210 g/mol, Mw=2330 g/mol for the copolymer, which corresponds to a polydispersity of 1.9.

Synthesis Example 2

[0212] A 6 L metal reactor having an anchor stirrer was initially charged with a mixture of C.sub.20-C.sub.24 olefins (1743 g, average molar mass 296 g/mol) and Solvesso 150 (1297 g, DHC Solvent Chemie GmbH, Speldorf). The mixture was heated to 150 C. in a nitrogen stream and while stirring. To this were added, within 5 h, a solution of di-tert-butyl peroxide (118.4 g, from Akzo Nobel) in Solvesso 150 (1041 g) and molten maleic anhydride (577 g). The reaction mixture was stirred at 150 C. for 1 h and then cooled down to 110 C. At this temperature, water (95 g) was added with increasing pressure and then the mixture was stirred for a further 3 h.

[0213] GPC (in THF) gave an Mn=1420 g/mol, Mw=2500 g/mol for the copolymer, which corresponds to a polydispersity of 1.8.

Synthesis Example 3

[0214] A 6 L metal reactor having an anchor stirrer was initially charged with a mixture of C.sub.20-C.sub.24 olefins (1743 g, average molar mass 296 g/mol) and Solvesso 150 (1297 g, DHC Solvent Chemie GmbH, Speldorf). The mixture was heated to 150 C. in a nitrogen stream and while stirring. To this were added, within 5 h, a solution of di-tert-butyl peroxide (23.7 g, from Akzo Nobel) in Solvesso 150 (912 g) and molten maleic anhydride (577 g). The reaction mixture was stirred at 150 C. for 1 h and then cooled down to 110 C. At this temperature, water (95 g) was added with increasing pressure and then the mixture was stirred for a further 3 h.

[0215] GPC (in THF) gave an Mn=1500 g/mol, Mw=3200 g/mol for the copolymer, which corresponds to a polydispersity of 2.1.

Use Examples

[0216] The additive formulations specified in table 2 were produced from the above synthesis examples by mixing with polyisobuteneamine (molar mass 1000), polypropylene glycol as carrier oil and solvent and dehazer and used in the use examples (compositions in parts by weight).

1) Calcium Compatibility Test:

[0217] 100 mL of motor oil (Shell Helix, FIG. 1, far left beaker, with a Ca content of 1500 ppm, Mg content of 1100 ppm and Zn content of 1300 ppm) were heated to 70 C. in the beaker and then 1 mL of corrosion inhibitor was added. Should the solution still be clear, a further 1 mL of inhibitor is added. If the solution turns cloudy, the test is considered to have been failed (e.g. FIG. 1, right-hand beaker). FIG. 1 shows, in the middle, the oil which has been admixed with copolymer according to synthesis example 1 (50% in solvent naphtha) and remains clear. In the right-hand beaker, dimer fatty acid (dimeric oleic acid; CAS: 61788-89-4, 20% in solvent naphtha) was used. Clearly visible cloudiness is apparent.

2) Steel Corrosion Test in Accordance with ASTM D 665 B

[0218] a) The fuel used was commercial 95 octane E0 gasoline fuel from Haltermann, additized with an additive package composed of polyisobutenamine and carrier oil. Added to the formulation were the corrosion inhibitors specified in the table that follows, and they were subjected to a corrosion test in accordance with ASTM D 665 B.

[0219] The comparison used was dimer fatty acid (dimeric oleic acid; CAS: 61788-89-4 as corrosion inhibitor, 20% in solvent naphtha).

TABLE-US-00001 Active content of corrosion inhibitor NACE Corrosion inhibitor [ppm] rating Base value - D Haltermann E0 (no additization) Base value - E Haltermann E0 (with additization) Formulation 1 dimer fatty acid 2 A Formulation 2 synthesis example 1 2.5 A Formulation 3 synthesis example 1 5 A

[0220] The assessment was made as follows:

[0221] A 100% rust-free

[0222] B++0.1% or less of the total surface area rusted

[0223] B+0.1% to 5% of the total surface area rusted

[0224] B 5% to 25% of the total surface area rusted

[0225] C 25% to 50% of the total surface area rusted

[0226] D 50% to 75% of the total surface area rusted

[0227] E 75% to 100% of the total surface area rusted

[0228] b) A further experiment was conducted analogously to a), but with an E0 gasoline fuel KS-0001829 CEC DF-12-09.

[0229] The results are as follows:

TABLE-US-00002 Active content of corrosion inhibitor NACE Corrosion inhibitor [ppm] rating KS-0001829 base E value (no additization) Formulation 13 dimer fatty acid 2 A Formulation 14 synthesis example 2 2 A Formulation 1 dimer fatty acid 2 A Formulation 7 synthesis example 3 2 B+ Formulation 11 dimer fatty acid 2 C

[0230] c) A further experiment was conducted analogously to a), but with a KS-0001858 MIRO 95 OCTANE E10 gasoline fuel.

[0231] The results are as follows:

TABLE-US-00003 Active content of corrosion inhibitor NACE Corrosion inhibitor [ppm] rating KS-0001858 base E value (no additization) Formulation 13 dimer fatty acid 2 B++ Formulation 14 synthesis example 2 2 B+ Formulation 1 dimer fatty acid 2 A Formulation 7 synthesis example 3 2 A Formulation 11 dimer fatty acid 2 B+

[0232] d) The test was conducted in accordance with standard ASTM D665 A (modified) with distilled water and ASTM D665 B (modified) with synthetic seawater in a mixture with diesel based fuel in accordance with EN590 B7, without performance additives. The modifications were that the temperature was 60 C. and the duration of the test was 4 hours.

TABLE-US-00004 Assessment in the Assessment in the ASTM D665A test ASTM D665B test Addition (with distilled water) (with synthetic seawater) No additions B E 140 mg/kg of sample A B according to preparation example 1

3) Copper Corrosion

a) In Gasoline

[0233] Copper coupons (dimensions 49251.5 mm, hole punched in the middle) were polished cautiously on both sides and on all edges with a polishing machine having the appropriate polishing brush without firm pressure. The polished coupons were rubbed thoroughly several times with a clean cloth with xylene and acetone, using rubber gloves. A 250 mL screwtop glass bottle was filled with 200 mL of fuel. The coupon was secured by a thread and suspended in the fuel bottle. The thread was clamped in the screw thread for fixing.

[0234] Storage was effected at room temperature (23 C.). After the first storage period (7 days) had passed, a sample was taken (20-30 mL), the glass bottle was closed again and the metal content was ascertained by means of atomic absorption spectroscopy. The storage was continued. After repeated removal and dropping of the liquid level, it was ensured that the copper coupon is fully covered by fuel.

[0235] The results are listed in table 1.

[0236] It is apparent from the results in table 1 that the compounds of the invention used, in equal dosage, exhibit a lower tendency to leach copper out of wetted surfaces in fuels than the dimer fatty acid used for comparison.

TABLE-US-00005 TABLE 1 Fuel E0 Fuel E0 Fuel E0 Fuel E10 Fuel E10 Fuel E10 from 2)b) from 2)b) from 2)b) from 2)c) from 2)c) from 2)c) Duration Duration Duration Duration Duration Duration [days] [days] [days] [days] [days] [days] 7 14 28 7 14 28 Active Copper Copper Copper Copper Copper Copper Active component content content content content content content component mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg No additization <0.1 <0.1 0.4 0.7 Formulation 12 0.1 0.2 0.5 0.8 Formulation 1 dimer fatty acid 2.0 0.2 0.4 0.8 0.9 1.7 3 Formulation 4 synthesis example 2 2.0 0.1 0.2 0.4 0.8 1.4 2.5 Formulation 5 synthesis example 2 4.0 0.2 0.3 0.6 1 1.7 3 Formulation 6 synthesis example 2 8.0 0.3 0.5 0.7 1.2 1.8 3 Formulation 7 synthesis example 3 2.0 0.1 0.3 0.5 0.9 1.4 2.7 Formulation 8 synthesis example 3 4.0 0.2 0.4 0.6 1.1 1.7 3 Formulation 9 synthesis example 3 8.0 0.3 0.5 0.8 1 1.8 2.8

TABLE-US-00006 TABLE 2 Synthesis Synthesis Synthesis example 1 example 2 example 3 Polyisobutene- Dimer fatty (50% in Solvent (40% in Solvent (40% in Solvent Solvent + amine Carrier oil acid Naphtha) Naphtha) Naphtha) dehazer Total Formulation 1 248 195 10 47 500 Formulation 2 248 195 5 47 495 Formulation 3 248 195 10 47 500 Formulation 4 248 195 5 47 495 Formulation 5 248 195 10 47 500 Formulation 6 248 195 20 47 510 Formulation 7 248 195 5 47 495 Formulation 8 10 47 500 Formulation 9 20 47 510 Formulation 10 248 195 30 47 520 Formulation 11 248 195 5 47 495 Formulation 12 248 195 47 490 Formulation 13 259 156 10 596 1021 Formulation 14 259 156 5 596 1016

b) In Diesel Fuel

[0237] To examine the corrosion characteristics of the sample from synthesis example 1 with respect to nonferrous metals, tests were conducted with zinc and copper wires.

[0238] 80 mL of Aral B7 EN590 fuel were dispensed into four bottles, to two of which were added 140 ppm of a sample from synthesis example 1. In one bottle with this sample and in one bottle without this sample was positioned degreased copper wire of length 20 cm and diameter 1 mm. Analogously, in one bottle with this sample and in one bottle without this sample was positioned degreased zinc wire of length 20 cm and diameter 1 mm. The copper or zinc content of the original fuel and after 6 weeks' storage was determined by means of atomic emission spectroscopy (ICP/OES) at 40 C.

TABLE-US-00007 Fuel Fuel Fuel (no addition, (addition of 140 ppm, (start) 6 weeks at 40 C.) 6 weeks at 40 C.) Zn content [mg/kg] <1 <1 <1 Cu content [mg/kg] <1 4 <1

[0239] It is apparent that the compounds of the invention have a corrosion-inhibiting effect on nonferrous metals, especially on copper.

4) PFI Engine Test DC M111E

[0240] An engine test over 60 hours was conducted in accordance with CEC F-020-98 with MIRO 95 octane E10 fuel and the deposits on the intake valves (internal valve deposits, IVD) and in the combustion chamber (total chamber deposits, TCD values) were determined.

[0241] In keep-clean mode, a TCD value of 4122 mg was found for the additized fuel without corrosion inhibitor, by contrast with a TCD value of 3940 mg for the additized fuel comprising corrosion inhibitor (formulation 10).

[0242] In addition, an IVD value of 116 mg/valve was found for the unadditized fuel and, in keep-clean mode, an IVD value of 2 mg/valve for the additized fuel without corrosion inhibitor, by contrast with an IVD value of 1 mg/valve for the additized fuel comprising corrosion inhibitor (formulation 10).

5) Keep Clean Test in a Direct Injection Gasoline Engine (DISI)

[0243] A commercially available DISI (direct injection spark ignition) engine (cylinder capacity 1.6 liters) was operated with an E10 gasoline fuel from MIRO (7% by volume of oxygen-containing components) at a speed of 4000 rpm for 50 hours.

[0244] In the first run, the fuel did not comprise any additives. The FR value oscillated between 0 and 1.

[0245] In the second run, the fuel comprised 520 mg/kg of formulation 10. The FR value oscillated between 2 and 3.

[0246] The FR value was determined in both runs. FR is a parameter which is generated by the engine management system according to the fuel injection into the combustion chamber. The formation of deposits is manifested by a rising FR value during a run. The more it grows, the more deposits are formed. If the FR value remains constant or decreases, the injector nozzle will also remain clean. In neither case is there any rise in the FR value, which indicates that the copolymer claimed does not have any adverse effect on injector cleanliness.