CORROSION INHIBITORS FOR FUELS AND LUBRICANTS

Abstract

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

Claims

1: A process, comprising inhibiting corrosion in a fuel or lubricant by contacting the fuel or lubricant with a copolymer, wherein the copolymer is obtained by: (I) copolymerizing (A) at least one ethylenically unsaturated mono- or dicarboxylic acid or derivatives thereof, (B) at least one -olefin having from at least 12 up to and including 30 carbon atoms, (C) optionally at least one further aliphatic or cycloaliphatic olefin which has at least 4 carbon atoms and is different than (B), and (D) optionally one or more further copolymerizable monomers other than monomers (A), (B) and (C), selected from the group consisting of (Da) vinyl esters, (Db) vinyl ethers, (Dc) (meth)acrylic esters of alcohols having at least 5 carbon atoms, (Dd) allyl alcohols or ethers thereof, (De) N-vinyl compounds selected from the group consisting of vinyl compounds of heterocycles containing at least one nitrogen atom, N-vinylamides or N-vinyllactams, (Df) ethylenically unsaturated aromatics, (Dg) ,-ethylenically unsaturated nitriles, (Dh) (meth)acrylamides and (Di) allylamines, to obtain a copolymer precursor; and then (II) optionally partly hydrolyzing anhydride functionalities, carboxylic ester functionalities, or both, present in the copolymer precursor, with the proviso that more than 90% of the anhydride and carboxylic ester functionalities present remain intact after the hydrolyzing, to obtain the copolymer.

2: The process of claim 1, comprising contacting the copolymer with a fuel comprising at least one metal selected from the group consisting of sodium, zinc, magnesium and calcium.

3: The process of claim 1, wherein monomer (A) is selected from the group consisting of acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, methyl methacrylate and maleic anhydride.

4: The process of claim 1, wherein monomer (B) is an -olefin having from 14 to 26 carbon atoms.

5: The process of claim 1, wherein olefin (C) is a polymer having more than 30 carbon atoms derived from units of propene, 1-butene, 2-butene, isobutene, or mixtures thereof, and having an average molecular weight Mw ranging from 500 to 5000 g/mol.

6: The process of claim 1, wherein a mixture of olefins (B) and (C) averaged to molar amounts thereof has at least 12 carbon atoms.

7: The process of claim 1, wherein the copolymerizing (I) includes a monomer (D) selected from the group consisting of (Da), (Db), (Dc), (De) and (Df).

8: The process of claim 1, wherein a molar ratio of (A)/((B) and (C)) (in total) is from 10:1 to 1:10.

9: The process of claim 8, wherein the molar ratio of monomer (B) to monomer (C) is from 1:0.05 to 10.

10: The process of claim 8, wherein a proportion of the one or more further copolymerizable monomers (D), based on an amount of the monomers (A), (B) and optionally (C) (in total), is 5 to 200 mol %.

11: The process of claim 1, wherein maleic anhydride is used as component (A) and the optional reaction step (II) is not conducted.

12: The process of claim 1, wherein maleic anhydride is used as component (A) and more than 90% and up to 99.9% of the anhydride functionalities remain intact in reaction step (II).

13: The process of claim 1, wherein the inhibiting corrosion involves inhibiting corrosion of at least one iron surface, steel surface, nonferrous metal surface, or combination thereof.

14: The process of claim 1, wherein the inhibiting corrosion involves inhibiting corrosion of copper and copper-containing alloys.

15: The process of claim 1, wherein the fuel is a diesel or gasoline fuel.

Description

EXAMPLES

GPC Analysis

[0217] 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

[0218] 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.

[0219] If hydrolysis is desired, water was subsequently added in the amount specified 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

[0220] 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. The active ingredient content was about 40%.

[0221] 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 (Comparison)

[0222] Water (19.9 g) was added to the product from synthesis example 1 at a temperature of 95 C. within 3 h and the mixture was then stirred for a further 11 h. The acid number was 104 mg KOH/g

USE EXAMPLES

1) Calcium Compatibility Test:

[0223] 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 (top of FIG. 1). Should the solution still be clear, a further 1 mL of inhibitor is added (bottom of FIG. 1). If the solution turns cloudy, the test is considered to have been failed (e.g. FIG. 1, middle beaker). FIG. 1 shows the oil which has been admixed with copolymer according to synthesis example 1 (40% in solvent naphtha) and remains clear. In the middle beaker, dimer fatty acid (dimeric oleic acid; CAS: 61788-89-4, 20% in solvent naphtha) was used. Clearly visible cloudiness is apparent.

[0224] The above synthesis examples were used to produce, by mixing with polyisobutenamine (molar mass 1000), polypropylene glycol as carrier oil and solvent and dehazer, the following adhesive formulations which were used in the use examples (compositions in parts by weight):

TABLE-US-00001 Figures in Carrier Solvent/ mg/kg Polyisobutenamine oil dehazer Anticorrosive Formulation 1 248 195 47 10 (comparative) (dimer fatty acid) Formulation 2 248 195 47 10 (comparative) (synthesis example 2) Formulation 3 248 195 47 10 (synthesis example 1)
2) Steel Corrosion Test in Accordance with ASTM D 665 B (Gasoline)

[0225] The fuel used was commercial EO CEC RF-12-09 gasoline fuel from Haltermann, additized with an additive package composed of polyisobutenamine and carrier oil as specified above. Added to the formulation were the corrosion inhibitors specified in the table that follows (each 40% in solvent naphtha), and they were subjected to a corrosion test in accordance with ASTM D 665 B.

[0226] The comparison used was dimer fatty acid as corrosion inhibitor (dimeric oleic acid; CAS: 61788-89-4, 40% in solvent naphtha).

TABLE-US-00002 Formulation Dosage [mg/kg] Anticorrosive NACE rating Haltermann E0 unadditized fuel D CEC RF-12-09 Formulation 1 500 10 mg/kg dimer B++ (comparative) fatty acid Formulation 2 500 10 mg/kg synthesis B++ (comparative) example 2 Formulation 3 500 10 mg/kg synthesis B+ example 1

[0227] The assessment was made as follows:

A 100% rust-free
B++ 0.1% or less of the total surface area rusted
B+ 0.1% to 5% of the total surface area rusted
B 5% to 25% of the total surface area rusted
C 25% to 50% of the total surface area rusted
D 50% to 75% of the total surface area rusted
E 75% to 100% of the total surface area rusted

[0228] It can be seen that similarly good results are achieved with the copolymer of the invention as with the comparative compounds.

3) Steel Corrosion Test in Accordance with ASTM D 665 B (Diesel)

[0229] The fuel used was commercial diesel fuel from South America which was admixed with an additive package as follows:

TABLE-US-00003 Figures in Detergent/antifoam/ mg/kg solvent/dehazer Anticorrosive Formulation 5 96 5 (comparative) (comparative) Formulation 6 96 12.5 (synthesis example 1)

[0230] The anticorrosive from formulation 5 as comparison is 2-(8-heptadecen-1-yl)-4,5-dihydro-1H-imidazol-1-ethanol, CAS No. 95-38-5, active ingredient content 90-100%.

[0231] In formulation 6 of the invention, the product from synthesis example 1 (40% in Solvesso 150) was used.

[0232] The formulations specified in the following table were subjected to a corrosion test in accordance with ASTM D 665 B:

TABLE-US-00004 NACE Formulation Dosage [mg/kg] Anticorrosive rating Formulation 4 Unadditized test E fuel from South America Formulation 5 101 2-(8-Heptadecen-1-yl)- C (comparative) 4,5-dihydro-1H-imidazol- 1-ethanol Formulation 6 108.5 Synthesis example 1 C

[0233] It can be seen that similarly good results are achieved with the copolymer of the invention as with the comparative compound.