Use of a complex ester to reduce fuel consumption

Abstract

The use of a complex ester obtainable by esterification reaction between aliphatic linear or branched C.sub.2- to C.sub.12-dicarboxylic acids, aliphatic linear or branched polyhydroxy alcohols with 3 to 6 hydroxyl groups, and, as chain stopping agents, aliphatic linear or branched C.sub.1- to C.sub.30-monocarboxylic acids or aliphatic linear or branched monobasic Ci- to C.sub.30-alcohols, as an additive in a fuel.

Claims

1. A method of reducing fuel consumption in the operation of an internal combustion engine, consisting of adding to a fuel a complex ester obtained by an esterification reaction between (A) at least one aliphatic linear or branched C.sub.2- to C.sub.12-dicarboxylic acid, (B) at least one aliphatic linear or branched polyhydroxy alcohol with 3 to 6 hydroxyl groups, wherein (A) and (B) are present in a ratio of at least 2 molecule units of component (A) and at least 3 molecule units of component (B), and (C) as a chain stopping agent (C1) at least one aliphatic linear or branched C.sub.1- to C.sub.30-monocarboxylic acid in case of an excess of component (B), or (C2) at least one aliphatic linear or branched monobasic C.sub.1- to C.sub.30-alcohol in case of an excess of component (A); wherein (C) is present in an amount of molecular units sufficient to partly or completely cap remaining free hydroxyl groups of component (B).

2. The method of claim 1, wherein component (A) is at least one selected from the group consisting of aliphatic linear C.sub.6- to C.sub.10-dicarboxylic acids.

3. The method of claim 1, wherein component (B) is at least one selected from the group consisting of glycerin, trimethylolpropane and pentaerythritol.

4. The method of claim 1, wherein component (C) is at least one selected from the group consisting of (C1) aliphatic linear or branched C.sub.8- to C.sub.18-monocarboxylic acids, and (C2) linear or branched C.sub.8- to C.sub.18-alkanols.

5. The method of claim 1, wherein the complex ester is composed of from 2 to 9 molecule units of component (A) and of from 3 to 10 molecule units of component (B), component (B) being in excess compared with component (A), with remaining free hydroxyl groups of (B) being completely or partly capped with a corresponding number of molecule units of component (C1).

6. A fuel composition consisting of, in a major amount, a gasoline fuel and, in a minor amount, at least one complex ester obtained by an esterification reaction between (A) at least one aliphatic linear or branched C.sub.2- to C.sub.12-dicarboxylic acid, (B) at least one aliphatic linear or branched polyhydroxy alcohol with 3 to 6 hydroxyl groups, wherein (A) and (B) are present in a ratio of at least 2 molecule units of component (A) and at least 3 molecule units of component (B), and (C) as a chain stopping agent (C1) at least one aliphatic linear or branched C.sub.1- to C.sub.30-monocarboxylic acid in case of an excess of component (B), or (C2) at least one aliphatic linear or branched monobasic C.sub.1- to C.sub.30-alcohol in case of an excess of component (A); wherein (C) is present in an amount of molecular units sufficient to partly or completely cap remaining free hydroxyl groups of component (B), and at least one fuel additive which is different from the complex ester and has detergent action, optionally containing one or more of at least one carrier oil or at least one tertiary hydrocarbyl amine of formula NR.sup.1R.sup.2R.sup.3 wherein R.sup.1, R.sup.2 and R.sup.3 are the same or different C.sub.1- to C.sub.20-hydrocarbyl residues with the proviso that the overall number of carbon atoms in formula NR.sup.1R.sup.2R.sup.3 does not exceed 30.

7. The fuel composition according to claim 6 wherein the fuel additive which is different from the complex ester and has detergent action, consists of at least one representative (D) selected from the group consisting of: (Da) mono- or polyamino groups having up to 6 nitrogen atoms, at least one nitrogen atom having basic properties; (Db) nitro groups, optionally in combination with hydroxyl groups; (Dc) hydroxyl groups in combination with mono- or polyamino groups, at least one nitrogen atom having basic properties; (Dd) carboxyl groups or their alkali metal or alkaline earth metal salts; (De) sulfonic acid groups or their alkali metal or alkaline earth metal salts; (Df) polyoxy-C.sub.2-C.sub.4-alkylene moieties terminated by hydroxyl groups, mono- or polyamino groups, at least one nitrogen atom having basic properties, or by carbamate groups; (Dg) carboxylic ester groups; (Dh) moieties derived from succinic anhydride and having hydroxyl and/or amino and/or amido and/or imido groups; and (Di) moieties obtained by Mannich reaction of substituted phenols with aldehydes and mono- or polyamines.

8. The fuel composition according to claim 6, additionally containing, as a further fuel additive in a minor amount, the at least one carrier oil.

9. The fuel composition according to claim 6, additionally containing, as a further fuel additive in a minor amount, the at least one tertiary hydrocarbyl amine of formula NR.sup.1R.sup.2R.sup.3 wherein R.sup.1, R.sup.2 and R.sup.3 are the same or different C.sub.1- to C.sub.20-hydrocarbyl residues with the proviso that the overall number of carbon atoms in formula NR.sup.1R.sup.2R.sup.3 does not exceed 30.

10. The fuel composition according to claim 7, wherein the at least one representative (D) is one or more (Da) polyisobutene monoamines or polyisobutene poly-amines having M.sub.n=300 to 5000, having at least 50 mol-% of vinylidene double bonds and having been prepared by hydroformylation of the respective polyiso-butene and subsequent reductive amination with ammonia, monoamines or poly-amines, in combination with at least one mineral or synthetic carrier oil.

11. An additive concentrate consisting of at least one complex ester obtained by an esterification reaction between (A) at least one aliphatic linear or branched C.sub.2- to C.sub.12-dicarboxylic acid, (B) at least one aliphatic linear or branched polyhydroxy alcohol with 3 to 6 hydroxyl groups, wherein (A) and (B) are present in a ratio of at least 2 molecule units of component (A) and at least 3 molecule units of component (B), and (C) as a chain stopping agent (C1) at least one aliphatic linear or branched C.sub.1- to C.sub.30-monocarboxylic acid in case of an excess of component (B), or (C2) at least one aliphatic linear or branched monobasic C.sub.1- to C.sub.30-alcohol in case of an excess of component (A); wherein (C) is present in an amount of molecular units sufficient to partly or completely cap remaining free hydroxyl groups of component (B), and at least one fuel additive which is different from the complex ester and has detergent action.

12. The additive concentrate according to claim 11, further comprising one or more (Da) polyisobutene monoamines or polyisobutene poly-amines having M.sub.n=300 to 5000, having at least 50 mol-% of vinylidene double bonds and having been prepared by hydroformylation of the respective polyiso-butene and subsequent reductive amination with ammonia, monoamines or poly-amines, and further comprising at least one mineral or synthetic carrier oil.

13. The method of claim 1, wherein components (A), (B), and (C) are used in amounts sufficient to provide the final composition with an acid number below 5 mg KOH/g.

14. The fuel composition of claim 6, wherein components (A), (B), and (C) are used in amounts sufficient to provide the final composition with an acid number below 5 mg KOH/g.

15. The additive concentrate of claim 11, wherein components (A), (B), and (C) are used in amounts sufficient to provide the final composition with an acid number below 5 mg KOH/g.

Description

(1) The examples which follow are intended to further illustrate the present invention without restricting it.

EXAMPLES

(2) All complex esters of the following examples were prepared according to the teachings of WO 99/16849, more precisely according to the general procedure as follows:

(3) The ratio of all three components, i.e. of mono fatty acids, of dicarboxylic acids or dimeric acids, respectively (together diacids), and of triols, was chosen in a way that OH and COOH groups were present in equimolar amounts. All reactants were added to the reactor and heated to approximately 140? C. Then, the temperature was stepwise increased to a maximum temperature of approximately 250? C. until the acid number was below 5 mg KOH/g. In case a tin catalyst was necessary to reach this level of residual acid number, the catalyst was removed by filtration.

(4) The following table shows the composition of the complex esters prepared (Examples 1a, 1b and 1c are for comparison, Examples 2 and 3 are according to the present invention):

(5) TABLE-US-00001 mono fatty acid diacid Triol Example 1a oleic acid dimeric tallow fatty trimethylolpropane (comparison) acid (18 wt. % in the complex ester) Example 1b oleic acid dimeric tallow fatty trimethylolpropane (comparison) acid (6 wt. % in the complex ester) Example 1c oleic acid dimeric tallow fatty trimethylolpropane (comparison) acid (39 wt. % in the complex ester) Example 2 isostearic sebacic acid pentaerythrol (invention) acid (15 wt. % in the complex ester) Example 3 C.sub.8-C.sub.10 acid adipinic acid trimethylolpropane (invention) (13 wt. % in the complex ester)

Example 4: Preparation of Gasoline Performance Package GPP 1

(6) 150 mg/kg of the complex ester of Example 1a, 1b, 1c, 2 or 3 above were mixed with a customary gasoline performance package containing as detergent additive component Kerocom? PIBA (a polyisobutene monoamine made by BASF SE, based on a poly-isobutene with M.sub.n=1000) and usual polyether-based carrier oils, Solvent Naphtha as a diluent and corrosion inhibitors in customary amounts.

Example 5: Engine Cleanliness Tests with GPP 1

(7) In order to demonstrate that the complex esters according to the present invention of Examples 2 and 3 do not decrease engine cleanliness and that the complex esters of the art of Example 1 exhibit worse performance, the average IVD values were deter-mined with gasoline performance package of Example 4 (GPP 1) and, for comparison, with the same gasoline performance package (GPP 1) with the customary detergent additive component Kerocom? PIBA but without any complex ester, each according to CEC F-20-98 with a Mercedes Benz M111 E engine using a customary RON 95 E10 gasoline fuel and a customary RL-223/5 engine oil. The following table shows the results of the determinations:

(8) TABLE-US-00002 average IVD Additive [mg/valve] GPP 1 without any complex ester 12 GPP 1 with 150 mg/kg of Example 1a 29 GPP 1 with 150 mg/kg of Example 1b 21 GPP 1 with 150 mg/kg of Example 1c 166 GPP 1 with 150 mg/kg of Example 2 9 GPP 1 with 150 mg/kg of Example 3 6

Example 6: Fuel Economy Tests

(9) A typical low sulphur US E10 gasoline was additized with the gasoline performance package of Example 4 (GGP 1) containing 150 mg/kg the complex ester of Example 2 or 3, respectively, and used to determine fuel economy in a fleet test with three different automobiles according to U.S. Environmental Protection Agency Test Protocol, C.F.R. Title 40, Part 600, Subpart B. For each automobile, the fuel consumption was determined first with unadditized fuel and then with the same fuel which now, however, comprised the above-specified gasoline performance package in the dosage as specified above. The following fuel savings were achieved: 2004 Mazda 3, 2.0 L l4: 1.03% (with Example 2); 0.75% (with Example 3) 2012 Honda Civic, 1.8 L l4. 1.02% (with Example 2); 1.32% (with Example 3) 2010 Chevy HHR, 2.2 L l4: 1.53% (with Example 2); 1.55% (with Example 3)

(10) On average, over all automobiles used, the result was an average fuel saving of 1.19% (with Example 2) and 1.21% (with Example 3).

Example 7: Preparation of Gasoline Performance Package GPP 2

(11) 150 mg/kg of the complex ester of Example 2 or 3, respectively, above were mixed with a customary gasoline performance package containing as detergent additive component Kerocom? PIBA (a polyisobutene monoamine made by BASF SE, based on a poly-isobutene with M.sub.n=1000) and usual polyether-based carrier oils, kerosene as a diluent, demulsifiers and corrosion inhibitors in customary amounts.

Example 8: Storage Stability

(12) 48.0% by weight of GPP 2 above containing complex ester of Example 2 or 3, respectively, and 37.7% by weight of xylene were mixed at 20? C. and stored thereafter in a sealed glass bottle at ?20? C. for 42 days. At the beginning of this storage period and then after each 7 days, the mixture was evaluated visually and checked for possible phase separation and precipitation. It is the aim that the mixture remains clear (c), homogeneous (h) and liquid (l) after storage and does not exhibit any phase separation (ps) or precipitation (pr). The following table shows the results of the evaluations:

(13) TABLE-US-00003 after 7 days c, h, l (for Example 2) c, h, l (for Example 3) after 14 days c, h, l (for Example 2) c, h, l (for Example 3) after 21 days c, h, l (for Example 2) c, h, l (for Example 3) after 28 days c, h, l (for Example 2) c, h, l (for Example 3) after 35 days c, h, l (for Example 2) c, h, l (for Example 3) after 42 days c, h, l (for Example 2) c, h, l (for Example 3) Result: pass (for Example 2) pass (for Example 3)