AU612153B2 - Diesel fuel composition - Google Patents

Abstract

A diesel fuel composition containing a diesel fuel and a minor proportion by weight of a quaternary ammonium salt soluble therein. The quaternary ammonium salt is effective in reducing fouling of injector nozzles and in improving combusion chamber and piston cleanliness of diesel engines.

Description

i~rc -7ri AU-AI-17945/ 8 8 WORLD INTELLECTUAL PROPERTY ORGANIZATION Internati nal Bureau 0 V PCT INTERNATIONAL APPLICATION P ILISjiED NDE THE PATENT COOPERATION TREATY (PCT) (51) International Patent Classification 4 1)I rn al P ication Number: WO 88/09365 1/22, 1/24, 1/30 A l (43) International ication Date: I December 1988 (01.12.88) (21) International Application Number: PCT/GB88/00415 (74) Agent: BAWDEN, Peter, Charles; Exxon Chemical Limited, Exxon Chemical Technology Centre, P.O. Box (22) International Filing Date: 25 May 1988 (25.05.88) 1, Abingdon, Oxfordshire OX13 6BB (GB).

(31) Priority Application Number: 8712442 (81) Designated States: AU, JP, US.

(32) Priority Date: 27 May 1987 (27.05.87) Published (33) Priority Country: GB With international search report.

Before t;ie expiration of the time limit for amending the claims and to be republished in the event of the receipt (71) Applicant (for all designated States except US): EXXON of amendments.

CHEMICAL PATENTS INC [US/US]; 1900 East Linden Avenue, Linden, NJ 07036 (US).

(72) Inventors; and Inventors/Applicants (for US only) SEXTON, Michael, David [GB/GB]; 2 Elbourne, Didcot, Oxfordshire 2 3 FEB 1989 OXII OBL COLE, Royston, David [GB/GB]; 1 Orchard Gardens, West Challow, Wantage, Oxfordshire OX12 9TL

AUSTRALIAN

21 DEC1988 PATENT OFFICE (54) Title: DIESEL FUEL COMPOSITION (57) Abstract A diesel fuel composition containing a diesel fuel and a minor proportion by weight of a quaternary ammonium salt soluble therein. The quaternary ammonium salt is effective in reducing fouling of injector nozzles and in improving combustion chamber and piston cleanliness of diesel engines.

illA lI DIESEL FUEL COMPOSITION This invention concerns a die? 1 fuel having a reduced tendency to form deposits in and around the combustion chambers of diesel engines.

Oxidation of fuel and incomplete combustion results in a phenomenon known as coking, that is the deposition of highly carbonaceous material in and around the combustion chambers of internal combustion engines. First, excessive deposits around the tip of fuel injectors in indirect injection diesel engines can impair engine performance leading to poor startability, power reduction, higher noise, higher fuel consumption, etc.. Second, deposits around the pistons can lead to ring sticking, bore polishing, etc.

leading to power reduction, high oil consuption, high emissions, etc.. In recent years these problems have become important because of the increasing use of indirect Sinjection diesel engines in passenger cars particularly those operating at high speeds.

It is therefore desirable to reduce deposits to 20 2 acceptable levels which do not result in impaired performance. Many products are known to reduce injector deposits when added to the fuel, whilst claims have also been made on general combustion chamber cleanliness.

We have now found that the tendency of diesel fuels to form deposits in and around the combustion chambers of the indirect injection diesel engines may be significantly 5e 'I i 4V A v 4. The basic application referred to in paragraph 2 of this Declaration first application ma in a Convention country in respect of the invention the subject of the application.

DECLARED at..ABINGDON UNITED KINGDOM* Sthis.Eighteenth .day ANUAR Signature. (6) |To TT CflP orI'1 .r

P

T p f- WO 88/09365 PCT/GB88/00415 -2reduced by incorporating in the fuel a quaternary ammonium compound. There exist several patents dating back to the 1950's, 1960's and early 1970's prior to the development of the high speed diesel engines) which propose the addition of quaternary ammonium compounds to distillate fuels for various functions although there is no suggestion that the addition of such compounds, will reduce the formation of deposits due to incomplete fuel combustion in and around combustion chambers.

Examples of such patents include U.S. Patent No 3158647 which discloses the use of quaternary ammonium fatty acid, phenate, and naphthenate salts in the stabilisation of distillate fuel oils. This patent relates to the problem of sludge deposition in distillate fuel oil during storage at ambient temperatures and the problem of sludge deposits causing clogging of burner filters etc.. This patent does not concern the formation of deposits in ard around the combustion chambers of diesel engines.

U.S. Patents No. 3008813 and 3346353 concern a petroleum distillate fuel containing an ashless oil soluble polymeric dispersant stabilising additive and a dialkyl dimethyl ammonium chloride or a dialkyl dimethyl ammonium nitrite, respectively. These additives are adapted to prevent the formation of persistent haze and stable emulsions when the petroleum distillate fuel is contacted with water during handling and storage.

WO 88/09365 PCT/GB88/00415 -3- U.S. Patent No 3397970 relates to a petroleum distillate oil containing a pour point depressing amount of a copolymer of ethylene and an olefinically unsaturated aliphatic ester monomer (for example vinyl acetate) said copolymer tending to promote the formation of water haze in said oil, and as an inhibitor of said haze a dimer of linoleic acid and quaternary ammonium salt selected from dicocyl dimethyl ammonium chloride and dicocyl dimethyl ammonium nitrite.

U.S. Patent No 3493354 discloses a diesel fuel additive containing a major amount of an organic barium compound in combination with a minor amount of a quaternary ammonium salt. The additive promotes the combustion of the fuel, thereby reducing the proportion of unburned hydrocarbons and suspended soot particles in the exhaust gases of diesel engines. The quaternary ammonium salts serves to prevent the extraction of barium by water with which the additive or fuel containing the additive may come into contact.

United Kingdom Patents 973826 and 1076497 relate to using quaternary ammonium compounds, particularly nitrates as distillate fuel stabilisers whereas United Kingdom Patent 1432265 proposes their use as antistatic agents together with polysulphones.

It is one object of the present invention to reduce the levels of deposits formed in and around the combustion chambers of diesel engines to acceptable levels withour impairing performance. -t is a furthr- object -f the pr-ese-nt-invention to produce an improved diesel fuel iTpiti o WO 88/09365 PCT/GB88/0(Q415 -4- According to our invention a diesel fuel compositionoruse in an indirect injection engine co idses a diesel fuel and a minor proportion _gt of a quaternary ammonium salt sol u erein.

The four residues connected to the quaternary nitrogen atom of the quaternary ammonium salt are essentially hydrocarbyl residues. These residues may be similar or dissimilar.

They may be substituted with functional groups or have incorporated therein functional groups as parts of the hydrocarbyl chain.

Usually one or two of these residues contain at least 6 carbon atoms while the remaining residues contain less than 6 carbon atoms. It is preferred that one of the residues contains at least 8 carbon atoms while the remaining residues contain less than 6 carbon atoms.

Usually the hydrocarbyl residues are alkyl groups, alkenyl groups, aryl groups or alkaryl groups. Examples of alkyl groups containing less than 6 carbon atoms are methyl, ethyl, isopropyl, propyl and butyl groups. Examples of alkyl groups containing more than 6 carbon atoms are dodecyl (lauryl), tetradecyl (myristyl), hexadecyl (cetyl) and octadecyl (stearyl) groups. Examples of alkenyl groups containing more than 6 carbon atoms are dodecenyl, tetradecenyl, octadecenyl (oleyl), and octadecadienyl (linoleyl) grpups. The residues containing more than 6 carbon atoms can be derived from natural fats and oils, A WO 88/09365 PCT/GB88/00415 for example coconut oil, soya bean oil, animal t.ail-r and the like. In such instances these re~iaues will consist essentially of mixe. a-~iyl groups containing 8 to 22 carbon atoms- As mentioned above, the hydrocarbyl residues may contain functional groups. Examples of functional groups which may be present in the residues are hydroxy, halide, ester, amide, ether, amine, and sulphide functions.

It is preferred that the anionic radical is a strong acid radical. Examples of strong acid radicals useful according to the invention are nitrate, sulphate, ethosulphate, sulphonate (both alkyl and alkylaryl sulphurised phenate, carboxylate, and borate. It is also possible to employ mixtures of anionic radicals.

When the quaternary ammonium compound is a sulphonate it can be made from: Alkylbenzene-sulphonic acids or alkylnaphthalenesulphonic acids examples of which include Benzene-sulphonic acids with straight-chain or branched single or multiple substituted alkyl radicals with 4-24 (preferably 8-20) carbon atoms in the aromatic nucleus, for example dodecylbenzene-sulphonic acid, dinonylDenzene-sulphonic acid, dodecylnaphthalenesulphonic acid etc.

I U.

WO 88/09365 PCT/GB88/00415 -6- Alkane-sulphonic acids including Sulphonic acids possessing straight-chain or branched alkyl radicals usually with 10-30 carbon atoms, for example tetradecyl sulphonic acid etc.

Alkene-sulphonic acids including Sulphonic acids which have straight-chain or branched alkenyl radicals usually with 15-30 carbon atoms, for example 2-eicosenyl sulphonic acid etc.

The sulphonic acids are typically obtained by sulphonation of alkyl substituted aromatic hydrocarbons, such as those obtained from the fractionation of petroleum by distillation and/or extraction, or by the alkylation of an aromatic hydrocarbon for example, benzene, toluene, xylene, naphthalene, diphenyl. The alkylation may be carried out in the presence of a catalyst with alkylating agents having from about 3 to more than 30 carbon atoms, such as, for example, haloparaffins, olefins that may be obtained by dehydrogenation of paraffins, polyolefins, or, for example, polymers of ethylene, propylene, butene, etc.

The alkaryl sulphonates usually contain from about 9 to about 20 or more carbon atoms, preferably from about 16 to about 50 carbon atoms per alkyl substituted aromatic moiety.

Wo ,88/09365 PCT/GB88/00415 -7- Quaternary ammonium sulphurised phenates are synthesised from sulphurised alkylphenols which have the general structure:

OH

p.

ou where R is'an alkyl radical, n is an integer from 0 to 4 and x is an integer from 1 to 4. The average number of carbon atoms in all of the R groups is preferably at least about 9 in order to ensure adequate solubility in oil. The individual R groups may contain from 5 to 40, preferably 8 to 20 carbon atoms. Alkylation of phenol may be carried out with alkylating agents of the types used to alkylate aromatic hydrocarbons in the manufacture of alkaryl sulphonates. Sulphurisation may be by reaction of the alkyl phenol with sulphur chloride or by reaction with sulphur. In the latter case, the alkyl phenol is usually present as the metal salt, although other sulphurisation promoters may be used, such as amines.

Quaternary ammonium carboxylates are synthesised from: WO 88/09365 PCT/GB88/00415 -8- Monocarboxylic acids including Aliphatic monocarboxylic acids possessing saturated or unsaturated straight or branched chains usually with 0-6 carbon atoms, for example, formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid.

Aromatic monocarboxylic acids with single or multiple substituted hydrocarbon radicals possessing saturated or unsaturated straight or branched chains usually with 0-35 (preferably 0-24) carbon atoms in the aromatic nucleus, for example, benzoic acid, 0-toluic acid, m-toluic acid, p-toluic acid, p-octylbenzoic acid, p-nonylbenzoic acid, dibutylbenzoic acid, salicylic acid, methyl salicylic acid, ethyl salicylic acid, octylsalicylic acid, nonylsalicylic acid, dodecylsalicylic acid, tetradecylsalicylic acid, octadecylsalicylic acid etc.

Polycarboxylic acids including Aliphatic polycarboxylic acids possessing saturated or unsaturated straight or branched chains usually with 0-80 (preferably 0-50) carbon WO 88/09365 PCT/GB88/90415 -9atoms, for example oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, tricarballylic acid, polymeric fatty acids (dimeric acid, trimeric acid etc.), alkenyl succinic acids (such as polyisobutenylsuccinic acid), or the anhydrides of such polycarboxylic acids.

Aromatic polycarboxylic acids with single or multiple substituted hydrocarbon radicals possessing saturated or unsaturated straight or branched chains usually with 0-35 (preferably 0-24) carbon atoms in the aromatic nucleus, for example phthalic acid, iso-phthalic acid, terephthalic acid, hemimellitic acid, trimellitic acid, trimeric acid, methyl phthalic acid, dodecylphthalic acid etc.

Preferred among the carboxylic acids are the simple monocarboxylic acids (such as formic acid and acetic acid), and the simple dicarboxylic acids (such as oxalic acid).

Many of the quaternary ammonium salts which may be employed according to the present invention are commercially available. It is preferred to use one of those readily available compounds. Alternatively the quaternary ammonium compounds can be synthesised in any suitable manner. Since the method of preparing the quaternary ammonium compounds is not part of the invention, the preparation of the compounds will not be describedAin detail. It should 1/ WO 88/09365 PCT/GB88/00.415 be noted, however, that we have two preferred methods for the synthesis of compounds such as quaternary ammonium sulphonates, sulphurised phenates and carboxylates.

In the first method a quaternary ammonium hydroxide is prepared by reacting a quaternary ammonium halide (for example the chloride) with an alkali metal hydroxide (for example sodium hydroxide) in an alcohol (for example methanol).

[R

4 NaOH NaX After removing the metal halide by filtration the solution of quaternary ammonium hydroxide is mixed with the acid HA where A is the desired anion in a suitable solvent and allowed to react:-

[R

4 HA [R 4

H

2 0 The rate of reaction may be increased by raising the reaction temperature above the ambient temperature. Once the reaction is complete the solvents and water are removed by distillation.

In the second method the organic acid HA is reacted with a metal oxide or hydroxide to form the metal salt: HA NaOH :--NaA H 2 0 If the reaction is done in a suitable solvent (for example heptane or toluene) the water formed during the reaction may be removed by refluxing the solvent and using a Dean and Stark trap. Once all the water has been removed the solution of the metal salt is treated with a quaternary ammonium halide: WO88/09365 PCT/GB88/00415

I-

-ll-I S: 1 -11- NaA [R 4

[R

4 NaCi The metal halide is removed by filtration and the solvent is removed by distillation. Alternatively, the solvent can be removed by distillation and the metal halide filtered from the final product.

The amount of quaternary ammonium salt which is added to the diesel fuel is a minor proportion by weight preferably less than 1 wt.% and most preferably 0.000001 to 0.1 wt.% especially 2 to 200 ppm.

Other additive materials commonly used in diesel fuel may also be included in the diesel fuel compositions according to the present invention. Such other additive materials may comprise corrosion inhibitors, dyes and the like.

The effect of quaternary ammonium salts employed according to the present invention on the fouling of injector nozzles and combustion chamber and piston cleanliness of diesel engines is illustrated by the following specific examples in which the following compounds are employed:, Di(2-hydroxyethyl) ethyl octadecenyl ammonium etho-sulphate (compound A) CH. -CH -'H -4 5- o- cHH-C( C0 r CHbIQH~~ P-H-CH iO £--cf 2

C

i WO 88109365 WO 8809365PCT/GB88/00415 -12- Cetyltrimethyl aminon ium suiphonate (compound B)

CHN'

I4 Cit 4 Clio II.

0 cetyltrimethy. ammonium nonyiphenyl sulphide (compound C) ci, 4 C 4.1- L J.2

C-)

0 srI ce, Niq Dimethyl dodecyl ethyl ammonium etho-suiphate (compound D) C Iz 4A16

CH.,

CH.,

0 0- 0 ip 1

L

~1 1- I WO 88/09365 PCT/GB88/004T15 -13- Dimethyl ethyl (3-stearyl amino propyl) ammonium etho-suiphate (compound E) IrI 1C4 C 14.

0 Caa Dimethyl ethyl (3-lauryl amino propyl) ammonium etho-sulphate (Compound F) IVH-(C4.Z C

CU

-0 S- CHL- C142 Dicocodimethyl ammonium formate (Compound G) Dicocodiuethyl ammonium borate (Compound H) Dicocodimethyl ammonium nony. phenyl sulphide (Compouiid I) Dicocdimethyl ammonium oxalate (Compound J) C143 C i

-I-

c N, (11 CIO CII)

B

WO 88/09365 PT/GB88/00,41 -14- Example 1 The effectiveness of quaternary ammonium salt additives on the coking of injector nozzles in diesel engines was determined using a Fiat Ritmo engine having the following specification.

Number of Cylinders Speed Maximum Power Bore Stroke Displacement Compression Ratio Oil Volume 4 in line 4500 rpm 42.66 kw 83 mm 79.2 mm 1.714 litres 20.5:1 5.0 litres In the tests the engine is run for 60 twenty minute cycles to simulate the urban driving cycle. Each cycle consists of four minute periods as follows: 1000 rpm idle 3000 rpm 65% potential speed 1600 rpm 35% potential speed 4200 rpm 90% potential speed 0 BHP 27 BHP 7.2 BHP 42 BHP 0 Load 40-45% Max Load 35-40% Max Load 70-8-% Max Load Before and after the engine test the injectors were rated according to the test method of ISO 4010. This test works on the principle of a vacuum being maintained across the injector at a specific needle lift. In order to maintain this vacuum at the desired level the air-flow into the p r I~ I -rr 'I _18111~ W WO 88/09365 PCT/GB88/00415 injector may vary. This air-flow into the injector is recorded. The air-flow into the injector becomes less as the injectors become coked. The results are recorded as the difference between clean and dirty, i.e. before and after tests air-flow. The formula used is as follows: Percent Air Flow Before Test After Test x 100 Loss Before Test In this and the following examples the results presented are the averages of four results at one specific setting of the injectors (0.1 mm lift).

The diesel fuel used in Example 1 was a diesel fuel obtained from Italy. The compound according to the present invention tested in this diesel fuel was Compound A. A comparative test has been carried out using a typical product already being sold for injector nozzle cleanliness application (commercial product). This is an additive of the type described in '-he UK Patent Application No.

85-30907. It is a mixture of a phenol compound and a cyclic amide derived from a dicarboxylic acid or anhydride.

The results obtained are shown in Table I, attached.

i Y i -s WO 88/09365 PCT/GB88/00415 -16- Example 2 The effectiveness of quaternary ammonium salts according to the invention on the coking of injector nozzles in diesel engines was determined using a Fiat Regata engine having the following specification.

Number of Cylinders Speed Maximum Power Bore Stroke Displacement Compression Ratio Oil Volume 4 in line 4600 rpm 48.00 kw 82.60 mm 90.00 mm 1.92 litres 21:1 5.7 litres In the test the engine was run for 60 twenty-minute cycles to simulate the urban driving cycle.

The total duration of 20 hours represents 1,600 km (1,000 miles) of city driving conditions.

Each cycle consisted of four five minute periods follows: (a) (b) (c) (d) 1100 3120 1680 4320 rpm rpm rpm rpm idle 65% potential speed 35% potential speed 90% potential speed 0 BHP 21.1 BHP 9.4 BHP 45.4 BHP as 0 Load 40-45% Max Load 35-40% Max Load 70-80% Max Load 1 i

I.I

iiii WO 88/09365 -17- Further test conditions were as follows:- PCT/GB8/00415 Manifold Air Temperature Coolant Outlet Coolant Temperature difference Oil Temperature at 3000 rpm Fuel Temperature Exhaust Temperature at 300 rpm 26± 92± 2 0

C

5-6 0

C

110± 2 0

C

48± 2oc 300 0

C

Various compounds according to the present invention were tested in .a UK commercial diesel fuel and the results obtained are presented in Table II.

Example 3 The tests in this example have been carried out as described for Example 2. Again, a UK commercial diesel fuel has been employed. A comparative result obtained with the commercial additive product mentioned in Example 1 is included in the attached Table III.

The compounds according to the present invention tested in this example are set out in Table 3.

P'r Of'- A, 'At: i I~ u WO 88/09365 PCT/GB8/00415 -18- TABLE 1 ANTI-COKING PERFORMANCE IN FIAT RITMO ENGINE TEST Fuel %FLOW LOSS Base Italian diesel Base 40 ppm of commercial product Base 37.5 ppm of compound A 71.0 44.7 10.0 TABLE II Fuel Base UK commercial diesel Base Base Base Base Base Base 25 25 37.5 37.5 37.5 37.5 ppm of compound B ppm of compound C\ ppm of compound G ppm of compound H ppm of compound I ppm of compound J Flow Reduction 65-70 (in repeat tests) 48.3 46.9 27.0 26.8 8.1 4I1 1 WO088/09365 PCT/G B88/00415 -19- TABLE III Fuel %Flow Reduction Base Base Base Base Base

UK

40 50 100 50 Commercial Diesel ppm of commercial product ppm of compound D ppm of compound D ppm of compound E 72 22.7 15. 4 20.5

Claims (12)

1. A method of inhibiting coking, especially injector nozzle coking, of indirect injection diesel engines which method comprises supplying said engine with a diesel fuel containing an amount within the range of from 0.000001 to 0.1 weight percent of a quaternary ammonium salt soluble in said fuel.

2. A method according to claim 1 wherein said quaternary ammonium salt has four residues connected to the quaternary nitrogen atom which are independently selected from hydrocarbyl residues which optionally contain at least one functional group as a substituent or as a member of the Shydrocarbon chain.

3. A method according to claim 1 or claim 2 wherein one or two of said residues contain at least 6 carbon atoms while the remaining residues contain less than 6 carbon atoms.

4. A method according to claim 3 wherein one of said residues contains at least 8 carbon atoms while the remaining residues contain less than 6 carbon atoms. *:fee:

5. A method according to any one of claims 2 to 4 wherein said hydrocarbyl groups are selected from alkyl, alkenyl, aryl and alkaryl groups.

6. A method according to any one of claims 2 to wherein said functional group is selected from hydroxy, carboxy, amide, amine, ester, ether, halide and sulphide. 0 0 1 -21-

7. A method according to any one of the preceding claims wherein the anionic radical of the quaternary ammonium salt is a strong acid radical.

8. A method according to any one of the preceding claims wherein the anionic radical of the quaternary ammonium salt is selected from sulphonate (alkyl or alkaryl), ethosulphate, sulphide, formate, oxalate and borate.

9. A method according to any one of the preceding claims wherein said quaternary ammonium salt is selected from: di(2-hydroxyethyl) ethyl octadecenyl ammonium oo.• etho-sulphate, cetyltrimethyl ammonium sulphonate cetyltrimethyl ammonium nonylphenyl sulphide dimethyl dodecyl ethyl ammonium etho-sulphate dimethyl ethyl (3-stearyl amino propyl) ammonium etho-sulphate dimethyl ethyl (3-lauryl amino propyl) ammonium etho-sulphate dicocodimethyl ammonium formate dicocodimethyl ammonium borate dicocodimethyl ammonium nonyl phenyl sulphide dicocodimethyl ammonium oxalate.

A method according to any one of the preceding claims wherein the improvement in anti-coking performance is measurable in the absence of other anti-coking additives by a reduction in percentage flow loss when supplied to an indirect injection diesel engine, according to the test method ISO 4010, of not less than 16% by comparison with the same untreated fuel.

11. A coke-inhibiting diesel fuel composition exhibiting an improvement in anti-coking performance in the i -22- absence of other anti-coking additives measurable by a reduction in percentage flow loss when supplied to an indirect injection diesel engine, according to the test method ISO 4010, of not less than 16% by comparison with the same untreated fuel, said composition containing an amount within the range of from 0.000001 to 0.1 weight percent of a quaternary ammonium salt soluble therein, said quaternary ammonium salt having four residues connected to the quaternary nitrogen atom which are independently selected from hydrocarbyl residues which optionally contain at least one function group as a substituent or as a member of the hydrocarbon chain, and wherein the anionic radical of the quaternary ammonium salt is a strong acid radical.

12. A coke-inhibiting diesel fuel composition containing as a coke-inhibiting additive in the absence of other coke-inhibiting additives from 37.5 to 200 ppm of a compound selected from: di(2-hydroxyethyl) ethyl octadecenyl ammonium etho-sulphate, cetyltrimethyl ammonium sulphonate i icetyltrimethyl ammonium nonylphenyl sulphide dimethyl dodecyl ethyl ammonium etho-sulphate dimethyl ethyl (3-stearyl amino propyl) ammonium etho-sulphate dicocodimethyl ammonium formate dicocodimethyl ammonium borate dicocodimethyl ammonium nonyl phenyl sulphide dicocodimethyl ammonium oxalate. DATED this 10th day of April, 1991. EXXON CHEMICAL PATENTS INC WATERMARK PATENT TRADEMARK ATTORNEYS 2nd Floor "The Atrium" 290 Burwood Road HAWTHORN VICTORIA 3122 AUSTRALIA 4:48(SC) caon ctl rmty m oi m n nlh l sl h d i eh ld d ci eh l a mn u t osl h t ii r i k. ~:~aai t d A INTERNATIONAL SEARCH REPORT Internatlonal ApplicatIon No PCT/GB 88/00415 I. CLASSIFICATION OF SUBJECT MATTER (it several classification symools apply, indicate ill) According to International Patent Classification (IPC) or to both National Classification and IPC IPC C 10 L 1/22; C 10 L 1/24; C 10 L 1/30 II. FIELDS SEARCHED Minimum Documentation Searched 7 Classification System Classification Symbols IPC 4 C 10 L Documentation Searched other than Minimum Documentation to the Extent that such Documents are Included in the Fields Searched I III. DOCUMENTS CONSIDERED TO 2E RELEVANT' Category Citation of Document, i with indication, where appropriate, of the relevant passages 1 Relevant to Claim No. X US, A, 3033665 (GASTON et al.) 1-3,5,7- 8 May 1962 11 see the whole document X US, A, 3158647 (MYERS) 1-3,5-11 24 November 1964 see the whole document cited in the application X WO, A, 85/00620 (CHEVRON RES. CO.) 1-11 14 February 1985 see claims 1-18; pages 1-3; examples X GB, A, 994496 (UNITED STATES BORAX AND 1-5,7-11 CHEMICAL CORP.) 10 June 1965 see the whole document X US, A, 3361793 (WAKEMAN et al.) 1-5,7-11 2 January 1968 see the whole document Special categories of cited documents: to "T later document published ater the International fling date "A doeument defining the general state of the art which la not or riority date and not In conflict with the apolication but cited to understand the principle or theory underlying the considered to be of particular relevance invention earlier document but published on or after the International X" document of Darticular relevance the claimed invention filing date cannot be considered novel or cannot be considered to document which may throw doubts on priority claim(s) or involve an inventive step which is cited to establish the Publication date of another document of particular relevance:' the claimed Invention citation or other special reason (as specified) cannot be considered to Involve an Inventive step when the document referring to an oral disclosure, use, exhibition or document is combined with one or more other such docu- other means monte, such combination being obvious to a person skilled document published prior to the international filing date but n the art. later than the pority date claimed document member of the same patent family IV. CERTIFICATION Date of the Actual Completion of the International Search 18th August 1988 Date of Milling of this international Search Report 1n ocn 4f International Searching Authority EUROPEAN PATENT OFFICE Form PCT/ISA210 (second sheet) (;anuary 195) -4 -2- International Appication No. PCT/GB 8a/00415 Ill. DOCUMENTS CONSIDERED TO BE RELEVANT (CONTINUED FROM THE SECOND SHEET) Category Citation of Documrent. with indiaitiofi, wrwee appropriate, of the r*evant passages Relevant to Claimn No US, A, 3493354 (JONES) 3 February 1970 see the whole document cited in the application US, A, 3560507 (WAKEMAN et al.) 2 February 1971 s'ee the whole document GB, A, 716187 (LUBRIZOL) 29 September 1954 see the whole document US, A, 3362801 (FARERI et al.) 9 January 1968 see the whole document US, A, 4626259 (ZAWESKI et al.) 2 December 1986 see the whole document 1-11 1-11 1,7-11 1-11 1-11 A Formn PCT ISA.210 (extra shoot) (January IllS) a 1 Crrsw1~ ANNEX TO THE INTERNATIONAL SEARCH tEPORT I ON IINIER NATIONAL PATENT APPLICATION NU. GB 8800415 SA 22519 This annex lists the patent family members relating to 'he patent documents cited in the above-mentioned international search report. The members are as contained in the European Patent Office EDP file on 12/09/88 Th'e European Patent Office is in no way liable for these particulars which are merely given for the purpose of information. Patent document Publication Patent family Publication cited in search report date member(s) date US-A- 3033665 None US-A- 3158647 None WO-A- 8500620 14-02-85 EP-A- 0151621 21-08-85 US-A- 4581151 08-04-86 US-A- 4564372 14-01-86 US-A- 4600409 15-07-86 GB-A- 994496 None US-A- 3361793 None US-A- 3493354 03-02-70 None US-A- 3560507 02-02-71 Nonr GB-A- 716187 None US-A- 3362801 None US-A- 4626259 02-12-86 None S Fr more details about this nne :see Official Journal of the European Pent Oie, o .S For more details about this annex :see Official Journal of the European Pntent Office, No. 12/82 r