COMPOSITIONS AND METHODS AND USES RELATING THERETO

Abstract

A fuel composition comprising as an additive the reaction product of a polycarboxylic acid compound of formula (I): (I) or an anhydride thereof; and an alcohol having at least 5 carbon atoms; wherein each of n and m may be 0 or a positive integer.

##STR00001##

Claims

1. A fuel composition comprising as an additive the reaction product of a polycarboxylic acid compound of formula (I): ##STR00011## or an anhydride thereof; and an alcohol having at least 5 carbon atoms; wherein each of n and m may be 0 or a positive integer.

2. A method of improving the performance of an engine, the method comprising combusting in the engine a fuel composition comprising as an additive the reaction product of a polycarboxylic acid compound of formula (I): ##STR00012## or an anhydride thereof; and an alcohol having at least 5 carbon atoms; wherein each of n and m may be 0 or a positive integer.

3. (canceled)

4. The composition according to claim 1 wherein the polycarboxylic acid or anhydride thereof is selected from itaconic acid, itaconic anhydride, 2-methylene glutaric acid, 2-methylene glutaric anhydride, 2-methylene adipic acid, 2-methylene adipic anhydride and isomers and/or mixtures thereof.

5. The composition according to claim 1 wherein the polycarboxylic acid is itaconic acid.

6. The composition according to claim 5 wherein the alcohol is selected from: alkanols of formula CH.sub.3(CH.sub.2).sub.xOH wherein x is from 4 to 23; branched or cyclic alkyl alcohols in which n is 0; alkenyl alcohols in which n is 0; and glycol ethers in which n is not 0.

7. The composition according to claim 6 wherein the alcohol is selected from: an alcohol of formula R′OH wherein R.sup.1 is an alkyl group having 8 to 30 carbon atoms; an alcohol of formula R′OH wherein R.sup.1 is an alkenyl group having 8 to 30 carbon atoms; and an alcohol of formula H—(OR).sub.n—OR.sup.1 wherein n is from 1 to 24, R is ethylene, propylene or isopropylene, and R.sup.1 is an unsubstituted alkyl group having 8 to 30 carbon atoms.

8. The composition according to claim 1 wherein the alcohol is selected from hexanol, octanol, nonanol, decanol, dodecanol, tetradecanol, cetyl alcohol, stearyl alcohol, 2-ethyl-1-butanol, 2-ethyl-1-hexanol, 2-ethyl-1-heptanol, 2-propylheptanol, 2-ethyl-1-decanol, 2-hexyl-1-decanol, 2-octyl-1-decanol, 2-hexyl-1-dodecanol, 2-octyl-1-dodecanol, 2-decyl-1-tetradecanol, isotridecanol, cyclohexanol, cyclooctanol, benzyl alcohol, citronellol, oleyl alcohol, 9-decen-1-ol, cis-3-hexen-1-ol, trans-2-hexen-1-ol, 5-hexen-1-ol, 6-methyl-5-hepten-2-ol, 1-octen-3-ol, trans-2-octen-1-ol, 10-undecen-1-ol and compounds of formula CH.sub.3(CH.sub.2).sub.xO(CH.sub.2CH(CH.sub.3)O).sub.yH or an isomer thereof wherein x is from 10 to 15, and y is from 10 to 20.

9. The composition according to claim 1 wherein the polycarboxylic acid compound and the alcohol are reacted in a molar ratio of from 2:1 to 1:2.

10. The composition according to claim 1 wherein the additive has an acid value of from 0.6 to 9.7 mmol H+/g.

11. The composition according to claim 1 wherein the fuel composition is a diesel fuel composition, which optionally comprises one or more further additives selected from: (i) a quaternary ammonium salt additive; (ii) the product of a Mannich reaction between an aldehyde, an amine and an optionally substituted phenol; (iii) the reaction product of a carboxylic acid-derived acylating agent and an amine; (iv) the reaction product of a carboxylic acid-derived acylating agent and hydrazine; (v) a salt formed by the reaction of a carboxylic acid with di-n-butylamine or tri-n-butylamine; (vi) the reaction product of a hydrocarbyl-substituted dicarboxylic acid or anhydride and an amine compound or salt which product comprises at least one amino triazole group; and (vii) a substituted polyaromatic detergent additive; and (viii) partial esters of substituted succinic acids.

12. The composition according to claim 11 wherein the diesel fuel composition further comprises a quaternary ammonium salt additive; wherein the quaternary ammonium salt additive is the reaction product of a nitrogen-containing species having at least one tertiary amine group and a quaternising agent wherein the nitrogen containing species is the reaction product of a hydrocarbyl-substituted acylating agent and a compound comprising at least one tertiary amine group and a primary amine, secondary amine or alcohol group; preferably wherein the quaternising agent is an ester quaternising agent.

13. The composition according to claim 1 wherein the fuel composition is a gasoline fuel composition, which optionally comprises one or more further additives selected from: (p) hydrocarbyl-substituted polyoxyalkylene amines or polyetheramines; (q) acylated nitrogen compounds which are the reaction product of a carboxylic acid-derived acylating agent and an amine; (r) hydrocarbyl-substituted amines wherein the hydrocarbyl substituent is substantially aliphatic and contains at least 8 carbon atoms; (s) Mannich base additives comprising nitrogen-containing condensates of a phenol, aldehyde and primary or secondary amine; (t) aromatic esters of a polyalkylphenoxyalkanol; (u) an additional quaternary ammonium salt additive; and (v) tertiary hydrocarbyl amines having a maximum of 30 carbon atoms.

14. The method according to claim 2 which combats deposits in the engine.

15. The method according to claim 2 wherein the engine is a modern diesel engine having a high pressure fuel system.

16. The method according to claim 15 wherein the improvement in performance is selected from one or more of: a reduction in power loss of the engine; a reduction in external diesel injector deposits; a reduction in internal diesel injector deposits; an improvement in fuel economy; a reduction in fuel filter deposits; a reduction in emissions; and an increase in maintenance intervals.

17. The method according to claim 2 which combats internal diesel injector deposits.

18. The method according to claim 2 which achieves a maximum exhaust temperature deviation of less than 30° C. in the DW10C test.

19. The method according to claim 2 wherein the engine is a direct injection spark ignition engine.

20. The method according to claim 19 wherein the improvement in performance is selected from one or more of: improved fuel economy; reduced maintenance, less frequent overhaul or replacement of injectors, improved driveability; improved power; and improved acceleration.

21. The method according to claim 2 which achieves “keep clean” performance.

22. The method according to claim 2 which achieves “clean up” performance.

Description

EXAMPLE 1

[0392] A 500 mL, 3-neck round bottom flask was fitted with a magnetic stirrer, condenser, Dean-Stark apparatus, gas inlet/outlet, stirrer hotplate and oil bath. Oleyl alcohol (206.19 g, 0.768 mol), itaconic acid (100 g, 0.768 mol) and p-toluenesulfonic acid (0.439 g, 2.30 mmol) were combined and heated to 165° C. (internal temperature). The reaction mass was held at 165° C. for 6 hours and water was removed. The reaction mass became homogenous and a colour change to orange was observed. After cooling to room temperature, the reaction mass was transferred to a 2 L separating funnel and toluene (270 mL) was added. The toluene-diluted reaction mass was washed with 1:1 water-methanol (1×540 mL), the organic phase separated and volatiles removed on the rotary evaporator, providing a viscous orange liquid (257.6 g).

[0393] The acid value of Additive A1 was 2.0 mmolH.sup.+/g.

EXAMPLE 2

[0394] Additive A2, an additive of the present invention was prepared as follows:

[0395] A 100 mL, 3-neck round bottom flask was fitted with a magnetic stirrer, condenser and stirrer hotplate. Citronellol (20 g, 0.128 mol), itaconic acid (16.52 g, 0.127 mol) and p-toluenesulfonic acid (0.073 g, 0.38 mmol) were combined and heated to 160° C. (internal temperature) for 6 hours. After cooling to room temperature, a sample (15 g) of the total reaction mass was taken and dissolved in toluene (15 mL). The toluene solution was washed with 1:1 water-methanol (1×30 mL), the organic phase separated and volatiles removed on the rotary evaporator, providing a viscous orange liquid (13.6 g).

[0396] The acid value of Additive A2 was 2.7 mmolH.sup.+/g.

EXAMPLE 3

[0397] Diesel fuel compositions were prepared by dosing additives to aliquots all drawn from a common batch of RF06 base fuel, and containing 1 ppm zinc (as zinc neodecanoate).

[0398] Table 1 below shows the specification for RF06 base fuel.

TABLE-US-00001 TABLE 1 Limits Property Units Min Max Method Cetane Number 52.0 54.0 EN ISO 5165 Density at 15° C. kg/m.sup.3 833 837 EN ISO 3675 Distillation 50% v/v Point ° C. 245 — 95% v/v Point ° C. 345 350 FBP ° C. — 370 Flash Point ° C. 55 — EN 22719 Cold Filter Plugging ° C. — −5 EN 116 Point Viscosity at 40° C. mm.sup.2/sec 2.3 3.3 EN ISO 3104 Polycyclic Aromatic % m/m 3.0 6.0 IP 391 Hydrocarbons Sulphur Content mg/kg — 10 ASTM D 5453 Copper Corrosion — 1 EN ISO 2160 Conradson Carbon Residue % m/m — 0.2 EN ISO 10370 on 10% Dist. Residue Ash Content % m/m — 0.01 EN ISO 6245 Water Content % m/m — 0.02 EN ISO 12937 Neutralisation mg KOH/g — 0.02 ASTM D 974 (Strong Acid) Number Oxidation Stability mg/mL — 0.025 EN ISO 12205 HFRR (WSD1,4) μm — 400 CEC F-06-A-96 Fatty Acid Methyl Ester prohibited

EXAMPLE 4

[0399] The performance of fuel compositions of the present invention in modern diesel engines having a high pressure fuel system may be tested according to the CECF-98-08 DW 10 method. This is referred to herein as the DW10B test.

[0400] The engine of the injector fouling test is the PSA DW10BTED4. In summary, the engine characteristics are:

[0401] Design: Four cylinders in line, overhead camshaft, turbocharged with EGR

[0402] Capacity: 1998 cm.sup.3

[0403] Combustion chamber: Four valves, bowl in piston, wall guided direct injection

[0404] Power: 100 kW at 4000 rpm

[0405] Torque: 320 Nm at 2000 rpm

[0406] Injection system: Common rail with piezo electronically controlled 6-hole injectors.

[0407] Max. pressure: 1600 bar (1.6×10.sup.8 Pa). Proprietary design by SIEMENS VDO

[0408] Emissions control: Conforms with Euro IV limit values when combined with exhaust gas post-treatment system (DPF)

[0409] This engine was chosen as a design representative of the modern European high-speed direct injection diesel engine capable of conforming to present and future European emissions requirements. The common rail injection system uses a highly efficient nozzle design with rounded inlet edges and conical spray holes for optimal hydraulic flow. This type of nozzle, when combined with high fuel pressure has allowed advances to be achieved in combustion efficiency, reduced noise and reduced fuel consumption, but are sensitive to influences that can disturb the fuel flow, such as deposit formation in the spray holes. The presence of these deposits causes a significant loss of engine power and increased raw emissions.

[0410] The test is run with a future injector design representative of anticipated Euro V injector technology.

[0411] It is considered necessary to establish a reliable baseline of injector condition before beginning fouling tests, so a sixteen hour running-in schedule for the test injectors is specified, using non-fouling reference fuel.

[0412] Full details of the CEC F-98-08 test method can be obtained from the CEC. The coking cycle is summarised below.

[0413] 1. A warm up cycle (12 minutes) according to the following regime:

TABLE-US-00002 Duration Engine Speed Torque Step (minutes) (rpm) (Nm) 1 2 idle <5 2 3 2000 50 3 4 3500 75 4 3 4000 100

[0414] 2. 8 hrs of engine operation consisting of 8 repeats of the following cycle

TABLE-US-00003 Duration Engine Speed Load Torque Boost Air After Step (minutes) (rpm) (%) (Nm) IC (° C.) 1 2 1750 (20) 62 45 2 7 3000 (60) 173  50 3 2 1750 (20) 62 45 4 7 3500 (80) 212  50 5 2 1750 (20) 62 45 6 10 4000 100 * 50 7 2 1250 (10) 20 43 8 7 3000 100 * 50 9 2 1250 (10) 20 43 10 10 2000 100 * 50 11 2 1250 (10) 20 43 12 7 4000 100 * 50 * for expected range see CEC method CEC-F-98-08

[0415] 3. Cool down to idle in 60 seconds and idle for 10 seconds

[0416] 4. 4 hrs soak period

[0417] The standard CEC F-98-08 test method consists of 32 hours engine operation corresponding to 4 repeats of steps 1-3 above, and 3 repeats of step 4. ie 56 hours total test time excluding warm ups and cool downs.

EXAMPLE 5

[0418] The ability of additives of the present invention to remove ‘Internal Diesel Injector Deposits’ (IDIDs) may be measured according to the test method CEC F-110-16, available from the Co-ordinating European Council. The test uses the PSA DW10C engine.

[0419] The engine characteristics as follows:

TABLE-US-00004 Design: Four cylinders in line, overhead camshaft, variable geometry turbocharger with EGR Capacity: 1997 cm.sup.3 Combustion chamber: Four valves, bowl in piston, direct injection Power: 120 kW @ 3750 rpm Torque: 340 Nm @ 2000 rpm Injection system: Common rail with solenoid type injectors Delphi Injection System Emissions control: Conforms to Euro V limit values when combined with exhaust gas post-treatment system

[0420] The test fuel (RF06) is dosed with 0.5 mg/kg Na in the form of Sodium Naphthenate+10 mg/kg Dodecyl Succinic Acid (DDSA).

[0421] The test procedure consists of main run cycles followed by soak periods, before cold starts are carried out.

[0422] The main running cycle consist of two speed and load set points, repeated for 6 hrs, as seen below.

TABLE-US-00005 Speed Torque Step (rpm) (N .Math. m) Duration (s) 1 3750 280 1470 1 - Ramp .fwdarw. 2 — — 30 2 1000  10 270 2 - Ramp .fwdarw. 1 — — 30

[0423] The ramp times of 30 seconds are included in the duration of each step.

[0424] During the main run, parameters including, Throttle pedal position, ECU fault codes, Injector balance coefficient and Engine stalls are observed and recorded.

[0425] The engine is then left to soak at ambient temperature for 8 hrs.

[0426] After the soak period the engine is re-started. The starter is operated for 5 seconds; if the engine fails to start the engine is left for 60 seconds before a further attempt. A maximum of 5 attempts are allowed.

[0427] If the engine starts the engine is allowed to idle for 5 minutes. Individual exhaust temperatures are monitored and the maximum Temperature Delta is recorded. An increased variation in Cylinder-to-Cylinder exhaust temperatures is a good indication that injectors are suffering from IDID. Causing them to either open slowly or stay open too long.

[0428] An example below of all exhaust temperatures with <30° C. deviation, indicating no sticking caused by IDID.

[0429] The complete test comprises of 6× Cold Starts, although the Zero hour Cold Start does not form part of the Merit Rating and 5×6 hr Main run cycles, giving a total of 30 hrs engine running time.

[0430] The recorded data is inputted into the Merit Rating Chart. This allows a Rating to be produced for the test. Maximum rating of 10 shows no issues with the running or operability of the engine for the duration of the test.

[0431] An example below:

TABLE-US-00006 Cold Start Exhaust temperature consistency Starting Exhaust Number of Temperature Attempts Max Cyi. Cold Start Maximum (1 = Maximum Deviation Start Y/N Merits first start) Deduction Merits Merits (° c.) Deduction Merits #0 not rated #1 Y 5 1 0 5 5 21.8 0 5 #2 Y 5 1 0 5 5 18.1 0 5 #3 Y 5 1 0 5 5 15.5 0 5 #4 Y 5 1 0 5 5 20.2 0 5 #5 Y 5 1 0 5 5 22.6 0 5 Total Merits 25 25 Main Run Operability Max Number Max Pedal Inject. of EDU Position at Balancing Main Maximum Fault Stall 1000 rpm/10 Coeff. Run Merits resets Deduction (Y/N) Deduction N .Math. m (%) Deduction (rpm) Deduction Merits #1 5 0 0 N 5 15.4 0 15 0 5 #2 5 0 0 N 5 13.5 0 15 0 5 #3 5 0 0 N 5 13.6 0 15 0 5 #4 5 0 0 N 5 13.8 0 15 0 5 #5 5 0 0 N 5 14.5 0 15 0 5 Global Rating - Summary (Merit/10) 10 25

EXAMPLE 6

[0432] A diesel fuel composition comprising additive A1 (70 ppm active) was tested according to the DW10C test method outlined in example 5 above. A final merit rating of 10 was achieved. The full results are provided in table 2. The temperature profile of the cylinder exhausts over a five minute period following a cold start after 30 hours running time is illustrated in FIG. 1.

TABLE-US-00007 TABLE 2 Cold Start Exhaust temperature consistency Starting Exhaust Number of Temperature Attempts Max Cyi. Cold Start Maximum (1 = Maximum Deviation Start Y/N Merits first start) Deduction Merits Merits (° c.) Deduction Merits #0 not rated #1 Y 5 1 0 5 5 9.3 0 5 #2 Y 5 1 0 5 5 6.2 0 5 #3 Y 5 1 0 5 5 6.4 0 5 #4 Y 5 1 0 5 5 6.9 0 5 #5 Y 5 1 0 5 5 6.3 0 5 Total Merits 25 25 Main Run Operability Max Number Max Pedal Inject. of EDU Position at Balancing Main Maximum Fault Stall 1000 rpm/10 Coeff. Run Merits resets Deduction (Y/N) Deduction N .Math. m (%) Deduction (rpm) Deduction Merits #1 5 0 0 N 5 16.5 0 9.2 0 5 #2 5 0 0 N 5 16.2 0 8.4 0 5 #3 5 0 0 N 5 16.2 0 8.5 0 5 #4 5 0 0 N 5 16.1 0 8.3 0 5 #5 5 0 0 N 5 16.5 0 8.6 0 5 Global Rating - Summary (Merit/10) 10 25

EXAMPLE 7

[0433] The ability of additives of the present invention to clean up IDIDs may be assessed according to a modification of the DW10C test described in example 5.

[0434] The In-House Clean Up Method developed starts by running the engine using reference diesel (RF06) dosed with 0.5 mg/kg Na+10 mg/Kg DDSA until an exhaust temperature Delta of >50° C. is observed on the Cold Start. This has repeatedly been seen on the 3.sup.rd Cold Start which follows the second main run, 12 hrs total engine run time.

[0435] Once the increased Exhaust temperature Delta is observed, the engine fuel supply is swapped to reference diesel, dosed with 0.5 mg/kg Na (as sodium naphthenate)+10 mg/kg DDSA+the Candidate sample. The fuel is flushed through to the engine and allowed to commence with the next Main run.

[0436] The ability of the Candidate additive to prevent any further increase in deposits or to remove the deposits can then be determined as the test continues.

EXAMPLE 8

[0437] The effectiveness of the additives of the present invention in older traditional diesel engine types maybe assessed using a standard industry test—CEC test method No. CEC F-23-A-01.

[0438] This test measures injector nozzle coking using a Peugeot XUD9 A/L Engine and provides a means of discriminating between fuels of different injector nozzle coking propensity. Nozzle coking is the result of carbon deposits forming between the injector needle and the needle seat. Deposition of the carbon deposit is due to exposure of the injector needle and seat to combustion gases, potentially causing undesirable variations in engine performance.

[0439] The Peugeot XUD9 A/L engine is a 4 cylinder indirect injection Diesel engine of 1.9 litre swept volume, obtained from Peugeot Citroen Motors specifically for the CEC PF023 method.

[0440] The test engine is fitted with cleaned injectors utilising unflatted injector needles. The airflow at various needle lift positions have been measured on a flow rig prior to test. The engine is operated for a period of 10 hours under cyclic conditions.

TABLE-US-00008 Time Speed Torque Stage (secs) (rpm) (Nm) 1 30 1200 ± 30 10 ± 2 2 60 3000 ± 30 50 ± 2 3 60 1300 ± 30 35 ± 2 4 120 1850 ± 30 50 ± 2

[0441] The propensity of the fuel to promote deposit formation on the fuel injectors is determined by measuring the injector nozzle airflow again at the end of test, and comparing these values to those before test. The results are expressed in terms of percentage airflow reduction at various needle lift positions for all nozzles. The average value of the airflow reduction at 0.1 mm needle lift of all four nozzles is deemed the level of injector coking for a given fuel.

EXAMPLE 9

[0442] Additive A3, an additive of the present invention was prepared using a method analogous to the methods described in examples 1 and 2.

[0443] The acid value of Additive A3 was 2.4 mmolH.sup.+/g.

EXAMPLE 10

[0444] A diesel fuel composition comprising additive A3 (70 ppm active) was tested according to the DW10B test method outlined in example 4 above.

[0445] FIG. 2 shows the performance of this composition compared with a base fuel composition comprising no additive.

EXAMPLE 11

[0446] A diesel fuel composition comprising additive A3 (70 ppm active) was tested according to the DW10C test method outlined in example 5 above. A final merit rating of 10 was achieved. The full results are provided in table 3.

TABLE-US-00009 TABLE 3 Cold Start Exhaust temperature consistency Starting Exhaust Number of Temperature Attempts Max Cyi. Cold Start Maximum (1 = Maximum Deviation Start Y/N Merits first start) Deduction Merits Merits (° c.) Deduction Merits #0 not rated #1 Y 5 1 0 5 5 8.4 0 5 #2 Y 5 1 0 5 5 7.5 0 5 #3 Y 5 1 0 5 5 7.8 0 5 #4 Y 5 1 0 5 5 6.4 0 5 #5 Y 5 1 0 5 5 6.9 0 5 Total Merits 25 25 Main Run Operability Max Number Max Pedal Inject. of EDU Position at Balancing Main Maximum Fault Stall 1000 rpm/10 Coeff. Run Merits resets Deduction (Y/N) Deduction N .Math. m (%) Deduction (rpm) Deduction Merits #1 5 0 0 N 5 16.0 0 7.7 0 5 #2 5 0 0 N 5 15.4 0 7.5 0 5 #3 5 0 0 N 5 15.5 0 8.0 0 5 #4 5 0 0 N 5 15.8 0 7.6 0 5 #5 5 0 0 N 5 15.4 0 7.6 0 5 Global Rating - Summary (Merit/10) 10 25