COMPOSITION, METHOD AND USE

Abstract

A method of reducing particulate emissions from a direct injection spark ignition engine, the method comprising combusting in the engine a gasoline composition comprising as an additive a quaternary ammonium compound.

Claims

1. A method of reducing particulate emissions from a direct injection spark ignition engine, the method comprising combusting in the engine a gasoline composition comprising as an additive a quaternary ammonium compound.

2. (canceled)

3. The method according to claim 1 wherein the quaternary ammonium compound 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 having at least one tertiary amine group may be selected from: 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; (ii) a Mannich reaction product comprising a tertiary amine group; (iii) a polyalkylene substituted amine having at least one tertiary amine group; (iv) a tertiary amine of formula R.sup.1R.sup.2R.sup.3N, wherein each of R.sup.1, R.sup.2 and R.sup.3 is independently an optionally substituted alkyl, alkenyl or aryl group; and (v) a cyclic tertiary amine.

4. The method according to claim 3 wherein the nitrogen-containing species having at least one tertiary amine group is the reaction product of an alcohol or amine including a tertiary amino group and an optionally substituted succinic acid or anhydride thereof.

5. The method according to claim 4 wherein the succinic acid or anhydride thereof is substituted with a polyisobutenyl group having a number average molecular weight of from 170 to 2800.

6. The method according to claim 3 wherein the alcohol or amine including a tertiary amino group is selected from dimethylaminopropanol, dimethylaminopropylamine, N,N-diethyl-1,3-diaminopropane, N,N-dimethylethylenediamine, N,N-diethylethylenediamine, N,N-dibutylethylenediamine, or combinations thereof.

7. The method according to claim 3 wherein the quaternising agent is selected from an ester of a carboxylic acid, epoxides optionally in combination with an acid, dialkyl sulfates, benzyl halides, hydrocarbyl substituted carbonates, alkyl halides, alkyl sulfonates, sultones, hydrocarbyl substituted phosphates, hydrocarbyl substituted borates, alkyl nitrites, alkyl nitrates, hydroxides, N-oxides or mixtures thereof, followed by an anion exchange reaction.

8. The method according to claim 7 wherein the quaternising agent is an ester of formula R.sup.5COOR.sup.0 wherein R.sup.0 is a C.sub.1 to C.sub.7 alkyl group and R.sup.5 is the residue of a carboxylic acid selected from a substituted aromatic carboxylic acid, an α-hydroxycarboxylic acid and a polycarboxylic acid.

9. The method according to claim 8 wherein the quaternising agent is an ester of a carboxylic acid selected from one or more of oxalic acid, phthalic acid, salicylic acid, maleic acid, malonic acid, citric acid, nitrobenzoic acid, aminobenzoic acid and 2, 4, 6-trihydroxybenzoic acid.

10. The method according to claim 8 wherein the quaternising agent is selected from dimethyl oxalate, methyl 2-nitrobenzoate, dimethylphthalate, dimethyltartrate and methyl salicylate.

11. The method according to claim 7 wherein the quaternising agent is selected from epoxides, optionally in combination with an acid, wherein the epoxide has the formula: ##STR00013## wherein each of R.sup.6, R.sup.7, R.sup.8, R.sup.9 is independently selected from hydrogen or an optionally substituted alkyl, alkenyl or aryl group, provided at least one of R.sup.6, R.sup.7, R.sup.8 and R.sup.9 is hydrogen.

12. The method according to claim 11 wherein each of R.sup.6, R.sup.7 and R.sup.8 is hydrogen and R.sup.9 is selected from phenyl, an optionally substituted alkyl or alkenyl group having 1 to 20 carbon atoms, hydrogen, CH.sub.2OR.sup.10 or CH.sub.2OCOR.sup.11 wherein each of R.sup.10 and R.sup.11 is an optionally substituted alkyl or aryl group having from 1 to 20 carbon atoms.

13. The method according to claim 11 wherein the epoxide is selected from styrene oxide, ethylene oxide, propylene oxide, butylene oxide, stilbene oxide and isopropyl glycidyl ether.

14. The method according to claim 7 wherein the epoxide quaternising agents are used in combination with an acid.

15. The method according to claim 14 wherein the acid is selected from: a small simple acid selected from formic acid, acetic acid, propionic acid and butyric acid; a fatty acid compound; and a hydrocarbyl substituted phthalic acid or succinic acid derivative.

16. The method according to claim 1 wherein the gasoline composition further comprises one or more additional components selected from: a) carrier oils; b) acylated nitrogen compounds which are the reaction product of a carboxylic acid-derived acylating agent and an amine; c) hydrocarbyl-substituted amines wherein the hydrocarbyl substituent is substantially aliphatic and contains at least 8 carbon atoms; d) mannich base additives comprising nitrogen-containing condensates of a phenol, aldehyde and primary or secondary amine; and e) aromatic esters of a polyalkylphenoxyalkanol.

17. The method according to claim 1 which reduces the number of particulates emitted per unit volume of exhaust gas and/or the total mass of particulates emitted per unit volume of exhaust gas.

18. The method according to claim 1 wherein the quaternary ammonium compound improves the performance of a particulate filter fitted to the exhaust of a direct injection spark ignition engine wherein the improvement in performance is selected from: increased longevity; an increase in maintenance intervals; and n increase in regeneration intervals.

19. The method according to claim 4 wherein the succinic acid or anhydride thereof is substituted with a polyisobutenyl group having a number average molecular weight of from 450 to 1500.

Description

EXAMPLE 1

[0358] Intermediate Additive A, the reaction product of a hydrocarbyl substituted acylating agent and a compound of formula (B1) was prepared as follows:

[0359] 554.36 g (0.467 moles) PIBSA (made from 1000 MW PIB and maleic anhydride) was charged to 1 litre vessel. The mixture was stirred and heated, under nitrogen to 120° C. 47.72 g (0.467 moles) DMAPA was added over 1 hour and the mixture heated to 140° C. for 3 hours, with concurrent removal of water using a Dean-Stark apparatus.

[0360] [Note: PIB herein means polyisobutene; PIBSA means polyisobutenyl-substituted succinic anhydride; DMAPA means dimethylaminopropylamine]

EXAMPLE 2

[0361] Additive B, an additive comprising a quaternary ammonium salt additive of the present invention was prepared as follows:

[0362] 333.49 g (0.262 moles) of Additive A mixed with 39.92 (0.262 moles) methyl salicylate under nitrogen. The mixture was stirred and heated to 140° C. for 8 hours. The non-volatile content was adjusted to 60% w/w with Caromax 20. The product mixture of this reaction was used without further processing as additive B and contained the quaternary ammonium salt(s) additive of the present invention, together with any unreacted raw materials, other reaction products and solvent.

EXAMPLE 3

[0363] Gasoline compositions were prepared comprising the additives listed in Table 2, added to aliquots all drawn from a common batch of RF83-8-91 reference fuel.

[0364] Table 1 below shows the specification for the RF83-8-91 reference fuel.

TABLE-US-00001 ANALYSES SPECIFICATIONS RESULTS METHODS Low calorific value calculated — 42.89 MJ/kg GC-Calculated C/H ratio — 6.770 Induction period ≥480 >528 minutes NF EN ISO 7536 Washed existent gums content ≤4 <1 mg/100 mL NF EN ISO 6246 Phosphorus content ≤0.0013 <0.0013 g/L ASTM D 3231 Lead content ≤0.005 <0.005 g/L ASTM D 3237 Copper corrosion 3 h, 50° C. 1a-1b 1b NF EN ISO 2160 Density at 15° C. 745.0-765.0 753.2 kg/m.sup.3 ASTM D 1298 Vapour pressure 550-650 mbar 605 mbar ISO 3007 IP 24.0-40.0  33.6° C. ASTM D 86  5% Vol —  46.9° C. 10% Vol 42.0-58.0  52.4° C. 20% Vol —  60.2° C. 30% Vol —  70.4° C. 40% Vol —  85.6° C. 50% Vol  90.0-110.0 103.4° C. 60% Vol — 114.9° C. 70% Vol — 123.9° C. 80% Vol — 140.0° C. 90% Vol 155.0-180.0 173.4° C. 95% Vol — 189.0° C. FP 190.0-215.0 197.3° C. Residue ≤2.0  0.7% (v/v) Losses —  2.2% (v/v) E 70° C. — 30.0% (v/v) E 100° C. — 48.2% (v/v) E 150° C. — 83.4% (v/v) E 180° C. — 92.2% (v/v) saturates content — 49.7% (v/v) NF M 07-086 Olefin content 10.0-14.0 12.1% (v/v) Aromatics content ≤45.0 38.2% (v/v) Oxygen content ≤0.1 ≤0.1% (m/m) Benzene content ≤5.0  0.4% (v/v) ASTM D 3606 Research octane number ≥95.0 97.5 index NF EN ISO 5164 Motor octane number ≥85.0 85.7 index NF EN ISO 5163 Sulfur content ≤400 0.8 mg/kg ASTM D 4294

[0365] The compositions listed in table 2 were prepared and the particulate emissions were measured as follows:

[0366] A vehicle test was carried out on a chassis dynamometer test bench with a BMW B48 direct injection spark ignition engine. The vehicle used was a mini Cooper S with a turbocharger and an engine capacity of 1998 cm. The engine was run at a constant speed of 3500 rpm for 24 hours.

[0367] The particle and emission measuring system is directly connected to the tailpipe of the vehicle. The unit consists of an exhaust gas flow meter (AVL EFM), a gas emission measuring unit (AVL GAS PEMS) and a particle counter (AVL PN PEMS).

[0368] Once the gas flow leaves the tailpipe it directly enters the exhaust flow meter and the passes a probe which extracts the required gas volume for further analysis in the gas emission measuring unit and the particle counter. The remaining gas flow is then released to the open and removed by the exhaust ventilation system. Prior to each test the system runs a calibration procedure which is required to ensure that measuring deviations between tests remains as small as possible. The whole unit is a system provided by AVL which can also be used on the open road for testing. For handling on the test bench it is mounted inside the vehicle with a rack.

[0369] To arrive at the final number in the table the following formula is used:

PE=(PN.Math.EF vol.Math.1000000)/(v/3600)

[0370] Where:

[0371] PE . . . Particle Emission in #/km

[0372] PN . . . Particle Number in #/cm.sup.3

[0373] EF vol . . . Exhaust flow volume in m.sup.3/s

[0374] v . . . Vehicle speed in km/h

[0375] The amounts are ppm by weight of total additive (non-volatiles) dosed into the gasoline base fuel.

TABLE-US-00002 TABLE 2 Com- Additive B Additive C Additive D Additive E Particulates position (mg/kg) (mg/kg) (mg/kg) (mg/kg) (#/cm.sup.3) Basefuel C — — — — 3.4 × 10.sup.7 1 250 (150) — — — 9.1 × 10.sup.3 2 150 (90)  — — — 5.6 × 10.sup.4 3 50 (30) — — — 1.1 × 10.sup.7 4 (com- — 1200 — — 2.3 × 10.sup.7 parative) 5 (com- — — 500 — 1.6 × 10.sup.7 parative) 6 (com- — — — 500 3.0 × 10.sup.7 parative)

[0376] Additive C (comparative) is a fully formulated commercial gasoline fuel additive package comprising polyisobutenyl succinimide (PIBSI) detergent.

[0377] Additive D (comparative) is a fully formulated commercial gasoline fuel additive package comprising a Mannich detergent.

[0378] Additive E (comparative) is a fully formulated commercial gasoline fuel additive package comprising a polyisobutenamine detergent.

[0379] The above results are also presented in FIG. 1.