USE OF AN ADDITIVE IN A FUEL COMPOSITION

Description

[0001] This invention relates to a fuel composition, in particular a gasoline composition for use in motor vehicles.

[0002] For many years manufacturers of spark ignition combustion engines have been striving for higher efficiency to make optimum use of the hydrocarbon fuels. But such engines require gasolines of higher octane number, which has been achieved in particular by addition of organo lead additives, and latterly with the advent of unleaded gasolines, by addition of MTBE. But combustion of any gasoline gives rise to emissions in the exhaust gases, e.g. of carbon dioxide, carbon monoxide, nitrogen oxides (NOx) and toxic hydrocarbons and such emissions are undesirable.

[0003] Motor gasolines have been discovered having high Octane Number but producing low emissions on combustion.

[0004] The present invention provides an unleaded blend composition having a Motor Octane Number (MON) of at least 80 comprising component (a) at least 5% or preferably at least 8 or 10% (by volume of the total composition) of at least one hydrocarbon having the following formula I

        R-CH₂-CH(CH₃)-C(CH₃)₂-CH₃     I

wherein R is hydrogen or methyl
and component (b) at least one saturated liquid aliphatic hydrocarbon having 4 to 12, 4-10 such as 5-10 e.g. 5 - 8 carbon atoms. In another embodiment component (b) is contained in at least one of isomerate, alkylate, straight run gasoline, light reformate, light hydrocrackate and aviation alkylate. Preferably the composition comprises at least one of an olefin (e.g. in amount of 1-30%) and/or at least one aromatic hydrocarbon (e.g. in amount of 1-50%, especially 3-28%) and/or less than 5% of benzene. The composition may preferably comprise 10-40% triptane, less than 5% benzene and have a Reid Vapour Pressure at 37.8°C measured according to ASTMD323 of 30-120kPa. The composition is usually an unleaded motor gasoline base blend composition.

[0005] The present invention also provides an unleaded formulated motor gasoline which comprises said base composition and at least one motor gasoline additive.

[0006] If R is hydrogen the hydrocarbon is triptane. If R is methyl the hydrocarbon is 2,2,3 trimethylpentane. Especially preferred is triptane. Triptane and 2,2,3 trimethylpentane may be used individually or in combination with each other, for example, in a weight ratio of 10:90 - 90:10, preferably, 30:70 - 70:30.

[0007] The hydrocarbon of formula I, preferably triptane may be present in amount of 5-95% or 8-90% such as 10-90%, or 15-65% e.g. 10-40% such as 20-35% by volume or 40-90% such as 40-55% or 55-80% or 8-35% such as 8-20% by volume. Unless otherwise stated all percentages in this specification are by volume, and disclosures of a number of ranges of amounts in the composition or gasoline for 2 or more ingredients includes disclosures of all sub-combinations of all the ranges with all the ingredients.

[0008] Triptane or 2,2,3 trimethylpentane may be used in a purity of at least 95% but is preferably used as part of a hydrocarbon mixture e.g. with at least 50% of the compound of formula I. This mixture may be obtained for example by alkylation of an iso alkane e.g. reaction of propene and iso butane or obtained via distillation of the product of a catalytic cracking reaction to give a C₄ fraction containing olefin and hydrocarbon, alkylation to produce a C_4-9 especially a C_6-9 fraction which is distilled to give a predominantly C₈ fraction, which usually contains trimethyl pentanes including 2,2,3 trimethyl pentane and/or 2,3,3 trimethyl pentane. To produce triptane this fraction can be demethylated to give a crude product comprising at least 5% of triptane, which can be distilled to increase the triptane content in the mixture; such a distillate may comprise at least 10% or 20% of triptane and 2,2,3 trimethylpentane but especially at least 50% e.g. 50-90% the rest being predominantly of other aliphatic C7 and C8 hydrocarbons e.g. in amount 10-50% by volume. Triptane may be prepared generally as described in Rec. Trav. Chim. 1939, Vol.58 pp 347-348 by J.P.Wibaut et al, which involves reaction of pinacolone with methyl magnesium iodide followed by dehydration (e.g. with sulphuric acid) to form triptene, which is hydrogenated e.g. by catalytic hydrogenation to triptane. Alternatively triptane and 2,2,3 trimethylpentane may be used in any commercially available form.

[0009] The invention will be further described with triptane exemplifying the compound of formula I but 2,2,3 trimethylpentane may be used instead or as well.

[0010] The gasoline composition also contains as component (b) at least one liquid saturated hydrocarbon of 5-10 carbons especially predominantly branched chain C₇ or C₈ compounds e.g. iso C₇ or iso C₈. This hydrocarbon may be substantially pure e.g. n-heptane, isooctane or isopentane or a mixture e.g. a distillation product or a reaction product from a refinery reaction e.g. alkylate. The hydrocarbon may have a Motor Octane Number (MON) of 0-60 but preferably has a MON value of 60-96 such as isomerate (bp 25-80°C). Research Octane Number RON may be 80-105 e.g. 95-105, while the ROAD value (average of MON and RON) may be 60-100.

[0011] Component (b) may comprise a hydrocarbon component having boiling point (preferably a final boiling point) higher than, preferably one boiling at least 20°C more than, the compound of formula I e.g. triptane such as 20-60°C more than triptane but less than 225°C e.g. less than 170°C and usually is of Motor Octane Number of at least 92 e.g. 92-100; such components are usually alkanes of 7-10 carbons especially 7 or 8 carbons, and in particular have at least one branch in their alkyl chain, in particular 1-3 branches, and preferably on an internal carbon atom and especially contain at least one -C(CH₃)₂- group.

[0012] The volume amount of the component (b) in total (or the volume amount of mixtures comprising component (b), such as the total of each of the following (if present) (i)-(iv)) (i) catalytic reformate, (ii) heavy catalytic cracked spirit, (iii) light catalytic cracked spirit and (iv) straight run gasoline in the composition is usually 10-80% e.g. 25-70%, 40-65% or 20-40%, the higher percentages being usually used with lower percentages of component (a).

[0013] Component (b) may be a mixture of the liquid saturated hydrocarbons e.g. a distillation product e.g. naphtha or straight run gasoline or a reaction product from a refinery reaction e.g. alkylate including aviation alkylate (bp 30-190°C) isomerate (bp 25-80°C), light reformate (bp 20-79°C) or light hydrocrackate. The mixture may contain at least 60% or at least 70% w/w e.g. 60-95 or 70-90% w/w liquid saturated aliphatic hydrocarbon.
Volume amounts in the composition of the invention of the component (b) mixtures (primarily saturated liquid aliphatic hydrocarbon fractions e.g. the total of isomerate, alkylate, naphtha and straight run gasoline (in each case (if any) present in the composition) may be 4-60%, such as 4-25% or preferably 10-55% such as 25-45%. Alkylate or straight run gasoline are preferably present, optionally together but preferably in the absence of the other, in particular in amount of 2-50% such as 10-45 e.g. 10-25%, 25-45% or 25-40%. The compositions of the invention may also comprise naphtha e.g. in volume amount of 0-25% such as 2-25%,10-25% or 2-10%.

[0014] The compositions may comprise a hydrocarbon component which is a saturated aliphatic hydrocarbon of 4-6 carbons and which is more volatile and has a lower boiling point (preferably a lower final boiling point) than the compound of Formula I in particular one boiling at least 30°C such as 30-60°C below that of triptane at atmospheric pressure, and especially is itself of Motor Octane Number greater than 88 in particular at least 90 e.g. 88-93 or 90-92. Examples of the hydrocarbon component include alkanes of 4 or 5 carbons in particular iso-pentane, which may be substantially pure or crude hydrocarbon fraction from alkylate or isomerate containing at least 30% e.g. 30-80% such as 50-70%, the main contaminant being up to 40% mono methyl pentanes and up to 50% dimethyl butanes. The hydrocarbon component may be an alkane of boiling point (at atmospheric pressure) 60-100°C less than that of triptane e.g. n and/or iso butane optionally in blends with the C₅ alkane of 99.5:0.5 to 0.5:99.5, e.g. 88:12 to 75:25. n Butane alone or mixed with isopentane is preferred, especially in the above proportions, and in particular with a volume amount of butane in the composition of up to 20% such as 1-15% e.g. 1-8, 3-8 or 8-15%.

[0015] Cycloaliphatic hydrocarbons e.g. of 5-7 carbons such as cyclopentane or cyclohexane may be present but usually in amounts of less than 15% of the total e.g. 1-10%.

[0016] Volume amounts in the composition of the total of isomerate, alkylate, naphtha, straight run gasoline, 4-6 carbon liquid aliphatic hydrocarbon (as defined above) and cycloaliphatic hydrocarbon (in each case if present) may be 5-60%, such as 8-25%, 15-55% such as 30-50%.

[0017] The gasoline compositions of the invention also preferably contain at least one olefin, (in particular with one double bond per molecule) which is a liquid alkene of 5-10 e.g. 6-8 carbons, such as a linear or branched alkene e.g. pentene, isopentene hexene, isohexene or heptene or 2 methyl 2 pentene, or a mixture comprising alkenes which may be made by cracking e.g. catalytically or thermally cracking a residue from crude oil, e.g. atmospheric or vacuum residue; the mixture may be heavy or light catalytically cracked spirit (or a mixture there of).
The cracking may be steam assisted. Other examples of olefin containing mixtures are "C6 bisomer", catalytic polymerate, and dimate. The olefinic mixtures usually contain at least 10% w/w olefins, such as at least 40% such as 40-80% w/w. Preferred mixtures are (xi) steam cracked spirit (xii) catalytically cracked spirit (xiii) C6 bisomer and (xiv) catalytic polymerate, though the optionally cracked catalytically spirits are most advantageous. Amounts in the total composition of the olefinic mixtures especially the sum of (xi)- (xiv) (if any present) maybe 0-55, e.g. 10-55 or 18-37 such as 23-35 or 20-55 such as 40-55% Amounts of (xi) and (xii) (if present) in total in the composition are preferably 18-55, such as 18-35, 18-30 or 35-55% (by volume).

[0018] The olefin or mixture of olefins usually has an MON value of 70-90, usually a RON value of 85-95 and a ROAD value of 80-92.

[0019] The volume amount of olefin(s) in total in the gasoline composition of the invention may be 0% or 0-30%, e.g. 0.1-30% such as 1-30% in particular 2-25, 5-30, (especially 3-10), 5-18.5, 5-18 or 10-20%. Preferably the composition contains at least 1% olefin and a maximum of 18% or especially a maximum of 14%, but may be substantially free of olefin.

[0020] The compositions may also contain at least one aromatic compound, preferably an alkyl aromatic compound such as toluene or o, m, or p xylene or a mixture thereof or a trimethyl benzene. The aromatics may have been added as single compounds e.g. toluene, or may be added as an aromatics mixture containing at least 30% w/w aromatic compounds such as 30-100% especially 50-90%. Such mixtures may be made from catalytically reformed or cracked gasoline obtained from heavy naphtha. Example of such mixtures are (xxi) catalytic reformate and (xxii) heavy reformate. Amounts of the single compounds e.g. toluene in the composition may be 0-35%, such as 2-33% e.g. 10-33%, while amounts of the aromatics mixtures especially the total of the reformates (xxi) & (xxii) (if any) in the composition may be 0-50%, such as 1-33% e.g. 2-15% or 2-10% or 15-32% v/v, and total amount of reformates (xxi), (xxii) and added single compounds (e.g. toluene) may be 0-50% e.g. 0.5-20% or 5-40, such as 15-35 or 5-25% v/v.

[0021] The aromatics usually have a MON value of 90-110 e.g. 100-110 and a RON value of 100-120 such as 110-120 and a ROAD value of 95-110. The volume amount of aromatic compounds in the composition is usually 0% or 0-50% such as less than 40% or less than 28% or less than 20% such as 1-50%, 2-40%, 3-28%, 4-25%, 5-20% (especially 10-20%), 4-10% or 20-35% especially of toluene. The gasoline composition may also be substantially free of aromatic compound. Amounts of aromatic compounds of less than 42%, e.g. less than 35% or especially less than 30% are preferred. Preferably the amount of benzene is less than 5% preferably less than 1.5% or 1% e.g. 0.1-1% of the total volume or less than 0.1% of the total weight of the composition.

[0022] The compositions may also contain at least one oxygenate octane booster, usually an ether, usually of Motor Octane Number of at least 96-105 e.g. 98-103. The ether octane booster is usually a dialkyl ether, in particular an asymmetric one, preferably wherein each alkyl has 1-6 carbons, in particular one alkyl being a branched chain alkyl of 3-6 carbons in particular a tertiary alkyl especially of 4-6 carbons such as tert-butyl or tert-amyl, and with the other alkyl being of 1-6 e.g. 1-3 carbons, especially linear, such as methyl or ethyl. Examples of such oxygenates include methyl tertiary butyl ether (MTBE), ethyl tertiary butyl ether and methyl tertiary amyl ether. The oxygenate may also be an alcohol of 1-6 carbons e.g. ethanol.

[0023] The volume amount of the oxygenate may be 0 or 0-25% such as 1-25%, 2-20%, 2-10% or 5-20% especially 5-15%, but advantageously less than 3% such as 1-3% (especially of MTBE and/or ethanol). The oxygenate may also be substantially absent from the composition or gasoline of the invention.

[0024] Aromatic amines e.g. liquid ones such as aniline may be present if at all in amount of less than 5% by volume, and are preferably substantially absent e.g. less than 100ppm. The relative volume ratio of the amine to triptane is usually less than 3:1 e.g. less than 1:2.

[0025] The composition of the invention contains components (a) and (b), and the formulated unleaded gasoline also contains at least one motor gasoline additive, for example as listed in ASTM D-4814 the contents of which is herein incorporated by reference or specified by a regulatory body, e.g. US California Air Resources Board (CARB) or Environmental Protection Agency (EPA). These additives are distinct from the liquid fuel ingredients, such as MTBE. Such additives may be the lead free ones described in Gasoline and Diesel Fuel Additives, K Owen, Publ. By J.Wiley, Chichester, UK, 1989, Chapters 1 and 2, USP 3955938, EP 0233250 or EP 288296, the contents of which are herein incorporated by reference. The additives maybe pre-combustion or combustion additives. Examples of additives are anti-oxidants, such as one of the amino or phenolic type, corrosion inhibitors, anti-icing additives e.g. glycol ethers or alcohols, engine detergent additives such as ones of the succinic acid imide, polyalkylene amine or polyether amine type and anti-static additives such as ampholytic surface active agents, metal deactivators, such as one of thioamide type, surface ignition inhibitors such as organic phosphorus compounds, combustion improvers such as alkali metal salts and alkaline earth metal salts of organic acids or sulphuric acid monoesters of higher alcohols, anti valve seat recession and additives such as alkali metal compounds, e.g. sodium or potassium salts such as borates or carboxylates and colouring agents, such as azodyes. One or more additives (e.g. 2-4) of the same or different types may be used, especially combinations of at least one antioxidant and at least one detergent additive. Antioxidants such as one or more hindered phenols e.g. ones with a tertiary butyl group in one or both ortho positions to the phenolic hydroxyl group are preferred in particular as described in Ex. 1 hereafter. In particular the additives may be present in the composition in amounts of 0.1-100ppm e.g. 1-20ppm of each, usually of an antioxidant especially one or more hindered phenols. Total amounts of additive are usually not more than 1000ppm e.g. 1-1000ppm.

[0026] The compositions and gasolines are free of organolead compounds, and usually of manganese additives such as manganese carbonyls.

[0027] The compositions and gasolines may contain up to 0.1% sulphur, e.g. 0.000-0.02% such as 0.002-0.01%w/w.

[0028] The gasoline compositions of the invention usually have a MON value of at least 80 e.g. 80-110 or 80-105 such as 98-105 or preferably 80 to less than 98, such as 80-95, 83-93 or 93-98. The RON value is usually 90-120 e.g. 102-120 or preferably 90-102 preferably 90-100 e.g. 90-99, such as 90-93 e.g. 91, or 93-98 e.g. 94.5-97.5, or 97-101 while the ROAD value is usually 85-115 e.g. 98-115 or preferably 85-98 such as 85-95 e.g. 85-90, or 90-95 or 95-98. Preferred gasoline compositions have MON 80-83, RON 90-93, and ROAD 85-90, or MON 83-93, RON 93-98 and ROAD 85-95 or MON 83-93, RON 97-101 and ROAD 90-95. The Net calorific value of the gasoline (also called the Specific Energy) is usually at least 18000 Btu/lb e.g. at least 18500, 18700 or 18,900 such as 18500-19500, such as 18700-19300 or 18900-19200; the calorific value may be at least 42MJ/kg e.g. at least 43.5 MJ/kg such as 42-45 or 43-45 such as 43.5-44.5MJ/kg. The gasoline usually has a boiling range (ASTM D86) of 20-225°C, in particular with at least 2% e.g. 2-15% boiling in the range 171-225°C. The gasoline is usually such that at 70°C at least 10% is evaporated while 50% is evaporated on reaching a temperature in the range 77-120°C preferably 77-116°C and by 185°C, a minimum of 90% is evaporated. The gasoline is also usually that 10-50% may be evaporated at 70°C, 40-74% at 100°C, 70-97% at 150°C and 90-99% may be evaporated at 180°C. The Reid Vapour Pressure of the gasoline at 37.8°C measured according to ASTM D323 is usually 30-120, e.g. 40-100 such as 61-80 or preferably 50-80, 40-65, e.g. 40-60 or 40-50Kpa.

[0029] The gasoline compositions, when free of any oxygenates usually have a H:C atom ratio of at least 1.8:1 e.g. at least 2.0:1 or at least 2.1 or 2.2:1, such as 1.8-2.3:1 or 2.0-2.2:1. Advantageously the gasoline composition meets the following criteria.

wherein Atom H:C is the fraction of hydrogen to carbon in the hydrocarbons in the composition, oxy means the molar fraction of oxygenate, if any in the composition, Net Heat of Combustion is the energy derived from burning 1lb (454g) weight of fuel (in gaseous form) in oxygen to give gaseous water and carbon dioxide expressed in Btu/lb units [MJ/kg times 430.35], and y is at least 350, 380, 410 or 430, in particular 350-440 e.g. 380-420 especially 400-420.

[0030] Preferably the motor gasoline of this invention comprises 10-90% of triptane, 10-80% of component (b), 0-25% naphtha, 0-15% of butane, 5-20% of olefin, 3-28% aromatics and 0-25% oxygenate, in particular with 5-20% aromatics and 5-15% olefins.

[0031] In a preferred embodiment of this invention the motor gasoline of this invention contains 8-65% of triptane (especially 15-35%), 0.1-30% such as 2-25% olefins, especially 3-14% and 0-35% aromatics such as 0-30% e.g. 5-35, 5-20 (especially 5-15%) or 20-30%, and 5-50% component (b) mixtures e.g. 10-45% such as 20-40%. Such gasolines may also contain oxygenates, such as MTBE especially in amount of less than 3% e.g. 0.1-3% and especially contain less than 1.5% benzene e.g. 0.1-1%. Such gasolines preferably have RON of 97-99, MON 87-90 and ROAD values of 92-94.5.

[0032] Examples of motor gasolines of the invention are ones with 5-25% triptane, 5-15% olefins, 15-35% aromatics and 40-65% component (b), in particular 15-25% triptane, 7-15%, olefins 15-25% aromatics and 45-52% component (b) mixture of RON value 96.5-97.5, or 5-15% triptane, 7-15% olefins, 15-25% aromatics and 55-65% compound (b) of RON value 94.5-95.5.

[0033] Examples of motor gasolines of the invention are ones having 1-15% e.g. 3-12% butane, 0-20% e.g. 5-15% ether e.g. MTBE, 20-80 e.g. 25-70% of refinery mixed liquid (usually C₆-C₉)streams (apart from naphtha) (such as mixtures of(i)-(iv) above), 0-25% e.g. 2-25% naphtha, 5-70% e.g. 15-65% triptane, with RON 93-100 e.g. 94-98, MON 80-98 e.g. 83-93 or 93-98, and RVP 40-80 such as 40-65Kpa. Such gasolines usually contain 1-30% e.g. 2-25% olefins and 2-30% e.g. 4-25% aromatics. Amounts of olefins of 15-25% are preferred for RON values of 94-98 e.g. 94-96 and 2-15% e.g. 2-7% for RON values of 96-100 such as 96-98.

[0034] Other examples of fuel compositions of the invention contain 8-18% triptane, 10-50% e.g. 25-40% of total component (b) mixture, 5-40% e.g. 20-35% of total aromatics mixture 15-60, e.g. 15-30% or 40-60% of total olefinic mixture and 0-15% total oxygenate e.g. 3-8% or 8-15%. Especially preferred compositions have 8-18% triptane, 25-40% total mixed component (b) mixture, 20-35% total aromatics, and 15-30% total olefinics, or 8-18% triptane, 15-40% total mixed component (b) mixture, 3-25% total aromatics mixture, and 40-60% total olefinic mixture.

[0035] Further examples of fuel compositions contain 20-40% triptane, 8-55% of the total component (b) mixture, e.g. 5-25% or 35-55%, and 0 or 5-25% e.g. 18-25% total aromatics mixture, 0-55 especially 10-55 or 40-55% total olefin mixture, especially preferred compositions having 20-40% triptane, 5-25% total component (b) mixtures, 3-25% total aromatics mixture and 40-60% total olefinic mixture, or 20-40% triptane, 35-55% total component (b) mixture 15-30% total aromatics mixture and 0-15% e.g. 5-15% total olefin mixture, or in particular 20-40% triptane, 25-45% or 30-50% total component (b) mixture, 2-15% total aromatics mixture 18-35% total olefins mixture, and especially 3-10% or 5-18% olefins, and 10-35% such as 10-20% aromatics (e.g. 10-18%).

[0036] Example of fuel compositions contain 30-55% e.g. 40-55% triptane, 5-30% total component (b) mixture 0-10% total aromatic mixture, 10-45% olefinic mixture and 0-15% oxygenates especially with the total of oxygenates and olefinic mixture of 20-45%. Other examples of fuel compositions contain 55-70% triptane, 10-45% total component b, e.g. 10-25% or 35-45%, and 0-10% e.g. 0 or 0.5-5% total aromatics Mixture, and 0-30% total olefinics mixtures, e.g. 0 or 15-30%, especially 55-70% triptane 10-25% total component (b) 0 or 0.5-5% total aromatics mixture and 15-30% total olefinic mixture.

[0037] Particularly preferred examples of fuel composition comprise 15-35% e.g. 20-35% triptane, 0-18.5% e.g. 2-18.5% olefin, 5-40% e.g. 5-35% aromatics 25-65% saturates and less than 1% benzene, and 18-65% e.g 40-65% triptane, 0-18-5% e.g. 5-18.5% olefins, 5-42% e.g. 5-28% aromatics, 35-55% saturates and less than 1% benzene.

[0038] Another fuel composition may comprise 25-40% e.g. 30-40% such as 35% of alkylate, 10-25% e.g. 15-25% such as 20% of isomerate, 10-25% e.g. 15-25% such as 20% of light hydrocrackate and 20-35% e.g. 20-30% such as 25% of triptane and optionally 0-5% butane. Such a composition is preferably substantially paraffinic and is substantially free of olefins and aromatics.

[0039] Other fuel compositions of the invention may have different ranges of the Antiknock Index (also known as The ROAD Index), which is the average of MON and RON.

[0040] For ROAD Indexes of 85.5-88.5, the compositions may comprise 8-30% triptane e.g. 15-30%, and 10-50% e.g. 20-40% total component (b) mixture, 5-30%, e.g. 5-20% total olefins and 10-40 e.g. 15-35% total aromatics, or 8-30% triptane, 10-50% total component (b) mixture, 5-40% total aromatic mixtures e.g. 20-30% and 10-60% e.g. 30-55% total olefinic mixtures.

[0041] For ROAD Indexes of 88.5-91.0 the compositions may comprise 5-25% (or 5-15%) triptane, 20-45% total component (b) mixture, 0-25% e.g. 1-10 or 10-25% total olefins, and 10-35% e.g. 10-20% or 20-35% total aromatics or 5-25% (5-15%) triptane, 20-45% total component (b) mixture, 0-35% total aromatic mixtures e.g. 1-15 or 15-35%, and 5-65% e.g. 5-30 or 30-65% total olefinic mixtures.

[0042] For ROAD Indexes of 91.0-94.0 the fuel compositions of the invention may comprise 5-65% e.g. 5-20, 20-30, 30-65 or 40-65% triptane and 5-40% (5-35%) e.g. 5-12 or 12-40% (12-30%) total component (b) mixture 1-30% e.g. 1-10 or 10-25% total olefins and 5-55% e.g. 5-15 or 15-35 or 35-55% total aromatics, or the above amounts of triptane with 0-55 e.g. 0.5-25% e.g. 10-25% or 25-55% of aromatic fractions and 0 or 10-60% e.g. 10-30% or 35-60% total olefin fractions.

[0043] For ROAD values of 94-97.9, the fuel compositions may comprise 20-65% triptane e.g. 40-65% triptane, 0-15% e.g. 5-15% total olefins, 0-20% e.g. 5-20% total aromatics and 5-50 e.g. 30-50% total component (b) mixture, or the above amounts of triptane and total component (b) mixture with 0-30% e.g. 10-30% aromatic fractions and 0-30 e.g. 5-30% olefinic fraction, or the above amounts of triptane e.g. 20-40% triptane, total component b mixture, total olefins and total aromatics, with 2-15% aromatic fractions and 18-35% olefinic fractions.

[0044] The invention can provide motor gasolines, in particular of 91,95,97,98 and 110 RON values, with desired high Octane Levels but low emission values on combustion in particular of at least one of total hydrocarbons, total air toxics, NOx, carbon monoxide, and carbon dioxide, especially of both total hydrocarbons and NOx. Thus the invention also provides the use of a compound of formula I, in particular triptane, in unleaded motor gasoline of MON at least 80 to less than 98, e.g. as an additive to or component therein, to reduce the emission levels on combustion, especially of at least one of total hydrocarbons, total air toxics NOx, carbon monoxide and carbon dioxide especially both of total hydrocarbons and NO_x. The invention also provides a method of reducing emissions of exhaust gases in the combustion of unleaded motor gasoline fuels of MON of at least 80 which comprises having a compound of formula I present in the fuel which is a gasoline of the invention. The invention also provides use of an unleaded gasoline of the invention in a spark ignition combustion engine to reduce emissions of exhaust gases. While the compositions of the invention may be used in supercharged or turbocharged engines, they are preferably not so used, but are used in normally aspirated ones. The compound of formula I e.g. triptane can reduce one or more of the above emission levels better than amounts of alkylate or a mixture of aromatics and oxygenate at similar Octane Number and usually decrease the fuel consumption as well.

[0045] The present invention is illustrated in the following Examples.

Examples 1-6

[0046] In these Examples 2,2,3 trimethylbutane (triptane) 99% purity was mixed with various refinery fractions and butane, and optionally methyl tertiary butyl ether, to produce a series of gasoline blends, for making unleaded motor gasolines.

[0047] Formulated gasolines were made by mixing each blend with a phenolic antioxidant 55% minimum 2,4 dimethyl-6-tertiary butyl phenol 15% minimum 4 methyl-2, 6-ditertiary-butyl phenol with the remainder as a mixture of monomethyl and dimethyl-tertiary butyl phenols.

[0048] In each case the gasolines were tested for MON and RON, and their Reid Vapour Pressure at 37.8°C and their calorific value, and their distillation properties. The results are shown in table 1.

Table 1

Example	1	2	3	4	5	6
Composition   % v/v
Triptane	10.0	50.0	50.0	25.0	25.0	60.0
Butane	10.0	5.0	5.0	5.0	5.0	5.0
Mixed Fractions (apart from	60.0	30.0	30.0	65.0	50.0	35.0

Naphtha) of which
Catalytic reformate	5.0	0	0	18.1	0	1.3
HCC	6.48	18.62	17.68	0	9.31	22.73
LCC	48.52	0	19.05	46.90	36.41	0.00
SRG	0	11.38	3.27	0	4.28	10.85
Isopentane	0	0	0	0	0	0.12
Naphtha	20.0	5.0	5.0	5.0	20.0	0.00
MTBE	0	10.0	0	0	0	0

Analysis, %v/v
Aromatics	14.1	6.3	8.5	19.1	10.0	7.9
Olefins	23.5	3.2	11.7	21.4	18.5	3.8
Antioxidant mg/l	15	15	15	15	15	15

Distillation °C
T 10%	43.6	58.0	58.4	51.2	54.0	60.0
T 50%	89.1	93.2	97.1	85.5	91.9	99.2
T 90%	154.0	177.8	176.9	140.4	159.0	185.0
Reid Vapour Pressure kPa	78.1	46.9	47.4	63.9	57.3	42.9
RON	95.0	97.3	97.0	97.0	95.0	99.4
MON	85.9	97.2	95.4	90.0	89.0	87.3
ROAD	90.45	97.25	96.2	93.5	92.0	93.35

[0049] In the above table mixed fractions means a blend of refinery fractions in which HCC is heavy catalytically cracked spirit, LCC is light catalytically cracked spirit and SRG is straight run gasoline.

Example 7

[0050] The combustion characteristics of the gasolines of Ex.1-6 were tested against standard unleaded gasolines. Combustion of the gasolines of Ex.1-6gave less carbon dioxide emissions than from equal volumes of the standard gasolines of similar ROAD Octane Number.

Example 8 and Comparative Ex A-C

[0051] The emission characteristics on combustion of a series of gasoline fuels with 25% of different components were compared, the components being heavy reformate (comp A), triptane (Ex8), alkylate (comp B) and a mix of 10% heavy reformate and 15% MTBE (comp C). The gasoline fuels and their properties were as follows. Formulated gasolines were made by addition of the phenolic antioxidant in amount and nature as in Ex1-7.

[0052] The fuels were tested in a single cylinder research engine at a number of different engine settings. The speed/load was 20/7.2 rps/Nm/, or 50/14.3 rps/Nm the LAMBDA setting was 1.01 or 0.95, and the ignition setting was set or optimized. The emissions of CO, CO₂, total hydrocarbons, NOx, and total air toxics (benzene, butadiene, formaldehyde and acetaldehyde) were measured from the exhaust gases. The results from the different engine settings were averaged and showed that, compared to the base blend (Comp. Ex. A) the emissions with the compositions containing heavy reformate and MTBE (Comp. C), 25% alkylate (Comp. B) and 25% triptane (Ex8) were reduced, the degrees of change being as follows.

Table 2

Example	% CO	%CO2	%THC	%NOx	%TAT	%FC
Comp C (MTBE	-4.9	-2.3	-6.2	-6.5	-9.2	+1.4
Comp B (alkylate)	-7.9	-4.5	-4.0	-8.0	-13.1	-2.9
8 /triptane	-9.6	-5.6	-6.6	-10.1	-18.7	-4.1

Where THC is total hydrocarbons, TAT is total air toxics. The Fuel Consumption (FC) was also measured in g/kWhr and the change relative to the base blend are also shown in Table 2.

Example 9-22

[0053] Gasolines were made up as in Ex 1-6 from components as shown in the table below, and had the properties shown. They gave low carbon dioxide emissions.

Examples 24-8 and Comparative Example D

[0054] Emission characteristics were obtained as in Ex.8 (apart from Lamba settings of 1.00 and 0.95 set for the base fuel (Comp.D) on combustion of a series of gasoline fuels with different components namely reformate, (high aromatics), (Comp.D), triptane, Ex.24-27 and triptane/ethanol Ex.28. Fuel consumption was also measured in g/kWhr. Formulated gasolines were made by addition of the phenolic antioxidant in amount and nature as in Ex.1-7. The compositions were as shown in Table 3. The results were expressed in Table 4 as the percentage change in emissions or in fuel consumption compared to Ex.D.

Table 3

Example	24	25	26	27	28	D
Composition   % v/v
Triptane	40	10	25	60	10
Butane	2.96	2.96	2.96	2.96		2.96
Mixed Fractions (apart from		87.04	72.04	37.04

Naphtha) of which
Catalytic reformate *		19.78	4.78		21.28	25.25
CCS	5	5	5	5	10	5
Steam cracked spirit *	37.2	47.42	47.42	17.2	9.7	47.42
SRG					15.72
Toluene						4.53
Naphtha					13.79
Ethanol					5
Heavy reformate					9.51
Cyclohexane	5	5	5	5	5	5
Light hydrocrackate *	7.93	7.93	7.93	7.93		7.93
C6 Bisomer *	1.91	1.91	1.91	1.91		1.91
Analysis, %v/v
Aromatics	15.0	31.2	21.7	7.8	31.1	39.2
Olefins	13.4	16.2	16.1	8.3	6.5	16.2
Sulphur % w/w	0.007	0.007	0.007	0.007	0.012	0.007
Antioxidant mg/l	10	10	10	10	10	10
Distillation °C%
T 10%
T 50%
T 90%
Reid Vapour Pressure kPa
RON	98.7	96.8	97.5	101.0	93.2	96.6
MON	86.1	82.8	83.7	89.6	82.4	82.5
ROAD	92.4	89.8	90.6	95.3	88.1	89.55

* Denotes that a different fraction was used, compared to the Examples in other Tables e.g. different raffinate.

Table 4

Example	% CO	% CO2	% THC	%NOx	% TAT	% Fuel Composition
25	-3.3	-2.1	-4.7	-4.0	-5.0	-1.4
26	-8.6	-3.8	-8.7	-7.0	-19.1	-2.5
27	-17.4	-6.8	-10.5	-18.0	-35.3	-4.5
24	-14.9	-5.0	-7.9	-12.2	-28.7	-3.4
28	-11.7	-2.2	-3.2	-10.3	-10.1	+0.1

Table 5

Example	F.G	29
Composition   % v/v
Triptane		25
Butane	0.75	0
Mixed Fractions (apart from Naphtha) of which
Catalytic reformate *	11.0	7.5
Steam cracked spirit *	31.5	30.0
Alkylate	40.9	37.5
Toluene	15.8	0
Analysis, %v/v
Aromatics	34.2	15.6
Olefins	8.2	7.8
Saturates	57.6	76.6
Sulphur ppm	7.3	10
Benzene %w/w	0.75	0.64
Antioxidant mg/l	10	10
Distillation % Evap. 70°C	18.8	21.6
E % 100°C	44.4	64.5
E % 150°C	92.8	93.3
E % 180°C	96.4	98
Reid Vapour Pressure kPa	56.8	52.2
RON	99.5	99.7
MON	87.6	89.3
ROAD	93.05	94.5

Examples 29 and Comparative Ex. F, G

[0055] 3 gasoline fuels (Ex.29, F and G) were compared for production of emissions on combustion in cars. The gasoline fuels had the compositions and properties as shown in Table 5 and the formulated gasolines included antioxidant as in Ex.1. The fuels met the requirements of 2005 Clean Fuel specification according to Directive 98/70 EC Annexe 3. The cars were regular production models, namely 1998 Ford Focus (1800cc), 1996-7 VW Golf (1600cc), 1998 Vauxhall Corsa (1000cc), 1994-5 Peugeot 106 (1400cc) and 1998 Mitsubishi GDI (1800cc) each fitted with a catalytic converter. The Corsa had 3 cylinders, the rest 4 cylinders, while the 106 had single point injection; the Mitsubishi had direct injection and the rest multipoint injection for their combustion.

[0056] 2 separate base fuel experiments (comp F & G) were done. The emissions were tested in triplicate in a dynamometer on the European Drive Cycle test as described in the MVEG test cycle (EC.15.04+EUDC) modified to start sampling on cranking and 11 sec. Idle as given in Directive 98/69 EC (the disclosure of which is hereby incorporated by reference). The EDC test over 11km comprises the ECE cycle (City driving test) repeated 4 times followed by the Extended Urban Drive Cycle test (incorporating some driving at up to 120km/hr). The emissions were measured out of the engine (i.e. upstream of the catalytic converter) and also as tailpipe emissions (i.e. downstream of the converter) and were sampled every second (except for the Focus) and cumulated over the test, the results being expressed as g emission per km travelled. The emissions of the first ECE cycle with the Focus were not measured. The emissions tested were for the total hydrocarbons, CO₂, CO and NO_x and the fuel consumption was determined on a gravimetric basis. The geometric means of the emission and consumption results across the 5 cars were obtained. The values for the Comparative fuels were averaged.

[0057] In the following tests, the CO₂ emissions averaged over the 5 cars were lower with the triptane fuel (Ex.29) compared to the averaged base fuel results (Comp.F, G), namely Total tailpipe emissions in EDC tests, EUDC test and ECE test, the reductions being respectively 2.8%, 2.7% and 2.8%. The Fuel Consumptions averaged over the 5 cars were lower with the triptane fuel (Ex.29) compared to the averaged base results (Comp.F, G) in those same tests, the reductions being respectively, 0.6%, 0.6% and 0.5%. The tailpipe emissions results for THC, CO and NO_x in at least some parts of the total EDC cycle showed trends towards triptane giving lower emissions than the base fuel, but the differences may or may not be confirmed in view of the limited number of vehicles tested.

[0058] The ECE tests simulates city driving and has 4 identical repeats of a specified speed profile, which profile has 3 progressively higher speed sections interspersed by zero speed sections (the average speed being 19km/hr). The first profile corresponds to driving from a cold start. In a cold engine, the effects of friction, lubricants and the nature of the fuel among others, differ from those with a hot engine in an unpredictable way, and it is with cold engines that most tailpipe emissions are produced, because the catalytic converter becomes increasingly effective at reducing emissions when it becomes hot. In addition a Lambda sensor upstream of the converter controls the fuel/air ratio entering the engine, but this is not effective with a cold engine (resulting in an unregulated fuel/air ratio); after cold start the sensor quickly becomes effective, (resulting in a regulated fuel/air ratio), even when the catalyst is not yet hot enough to be effective. Thus cold start operations are different from hot running operations and yet contribute to a large amount of tailpipe emissions.

[0059] The out of engine results from the first profile ECE tests (simulating cold start) with the above fuels (Ex.29 and Comp.F, G) were the same as the tailpipe emissions as the catalyst was not effective then. The results in these cold start tests for CO₂, HC, CO and NO_x averaged over the Golf, Corsa, Peugeot and Mitsubishi, and also averaged over the Golf, Corsa and Peugeot showed trends toward triptane giving lower emissions than the base fuel, but the differences may or may not be confirmed in view of the limited number of vehicles tested.

[0060] This period of cold start simulated as above may correspond in real life to a period of time or distance, which may vary, depending on how the car is driven and/or ambient conditions e.g. up to 1 km or 4 or 2 min, or a temperature of the engine coolant (e.g. radiator water temperature) of up to 50°C. The car engine may also be deemed cold if it has not been operated for the previous 4hr before start, usually at least 6hr before start.

[0061] Thus the present invention also provides of method of reducing emissions of exhaust gases in the combustion of unleaded gasoline fuels of MON of at least 80 e.g. 80 to less than 98 from cold start of a spark ignition combustion engine, which comprises having a compound of formula I present in the fuel which is a gasoline of the invention.

Claims

1. Use of a compound of formula I,

        R-CH₂-CH(CH₃)-C(CH₃)₂-CH₃     I

wherein R is hydrogen or methyl in an unleaded motor gasoline of MON of at least 80 and less than 98 to reduce emissions of exhaust gases on combustion thereof.

2. Use according to claim 1 in which the unleaded formulated motor gasoline having a MON of 80 to less than 98 comprises a base blend composition having a Motor Octane Number (MON) of at least 80 comprising component (a) at least 5% (by volume of the total composition) of at least one hydrocarbon having the following formula I

        R-CH₂-CH(CH₃)-C(CH₃)₂-CH₃     I

wherein R is hydrogen or methyl and component (b) at least one saturated liquid aliphatic hydrocarbon having 4 to 12 carbon atoms, and at least one motor gasoline additive selected from anti-oxidants, corrosion inhibitors, anti-icing additives, engine detergent additives, anti-static additives, metal deactivators, surface ignition inhibitors, combustion improvers, anti valve seat recession additives and colouring agents.

3. Use according to claim 1 to reduce emissions on cold start of a spark ignition combustion engine.

4. Use according to any one of the preceding claims to reduce emissions of at least one of carbon dioxide, carbon monoxide, nitrogen oxides, total air toxics and total hydrocarbons.

5. Use according to claim 4 to reduce emissions of carbon dioxide.

6. Use according to any one of claims 2 to claim 5 wherein said composition has a MON value of 80 to less than 98 and saturated hydrocarbon has 4 to 10 carbons.

7. Use according to claim 6 in which the gasoline comprises as component (a) at least 8% by volume of triptane and said saturated hydrocarbon has 5 to 10 carbon atoms.

8. Use according to any one of claims 2 to 7 wherein component (b) is contained in at least one of isomerate, alkylate, straight run gasoline, light reformate, light hydrocrackate and aviation alkylate.

9. Use according to claim 8 wherein said composition comprises at least 8% by volume of triptane and wherein component (b) is at least one of isomerate, alkylate, aviation alkylate and straight run gasoline and comprises at least one saturated liquid aliphatic hydrocarbon having 5-10 carbon atoms.

10. Use according to any one of claims 2 to 9 wherein said composition comprises at least one saturated aliphatic hydrocarbon having 4-6 carbons, which has a lower boiling point than triptane and has a Motor Octane Number greater than 88.

11. Use according to any one of claims 2 to 10 wherein said composition comprises at least one saturated aliphatic hydrocarbon having 5-10 carbon atoms, which has a higher boiling point than triptane and has a Motor Octane Number greater than 92.

12. Use according to any one of claims 2 to 11 wherein said composition comprises at least one olefin which is an alkene of 5-10 carbons, with a MON value of 70-90 in amount of 1-30%, preferably 5-20% (by volume).

13. Use according to any one of claims 2 to 12 wherein said composition comprises at least one of catalytically cracked spirit, steam cracked spirit, C₆ bisomcr, catalytic polymerate and dimate.

14. Use according to claim 13 wherein said composition comprises catalytically cracked spirit.

15. Use according to any one of claims 2 to 14 wherein said composition also comprises at least one aromatic compound of MON value 90-110, in amount of 2-40% especially 3-28% (by volume).

16. Use according to any one of claims 2 to 15 wherein said composition also comprises at least one aromatic compound added as single compounds or added as an aromatics mixture made from catalytically reformed or cracked gasoline obtained from heavy naphtha.

17. Use according to any one of claims 2 to 16 wherein said composition also comprises at least one oxygenate octane booster of MON value of at least 96-105 in amount of 1-25% (by volume).

18. Use according to any one of claims 2 to 17 wherein said composition has a Reid Vapour pressure at 37.8° C measured according to ASTM D323 of 40 - 100 kPa.

19. Use according to any one of claims 2 to 18 wherein said composition meets the following criterion

wherein Atom H:C is the fraction of hydrogen to carbon in the hydrocarbons in the composition, oxy means the molar fraction of oxygenate, if any, in the composition, Net Heat of Combustion is the energy derived from burning 1lb (454g) weight of fuel (in gaseous form) in oxygen to give gaseous water and carbon dioxide expressed in Btu/lb units [MJ/kg times 430.35], and y is at least 350 in particular 350-440, and ROAD is the average of Motor Octane Number and Research Octane Number.

20. Use according to any one of claims 2 to 19 wherein said composition comprises (by volume) 10-90% of triptane, 10-80% of component (b), 0-25% naphtha, 0-15% of butane, 0-20% of olefin, 3-28% aromatics and 0-25% oxygenate.

21. Use according to any one of claims 2 to 19 wherein said composition comprises 5-20% aromatics, and 5-18.5% olefins (by volume).

22. Use according to any one of claims 2 to 19, wherein said composition comprises (by volume) 8-65% of triptane, especially 15-35%, 0.1-30% such as 2-25% olefins, especially 3-14% and 5-35% aromatics, 5-50% component (b) mixtures, oxygenates, in amount of less than 3% and less than 1.5% benzene e.g. 0.1-1%, and having RON of 97-99, MON 87-90 and ROAD values of 92-94.5.

23. Use according to any one of claims 2 to 19, wherein said composition comprises (by volume) 5-25% triptane, 5-15% olefins, 15-35% aromatics and 40-65% component (b), in particular 15-25% triptane, 7-15% olefins, 15-25% aromatics and 45-52% component (b) mixture and of RON value 96.5-97.5.

24. Use according to any one of claims 2 to 19, wherein said composition comprises (by volume) 1-15% butane, 0-20% MTBE, 20-80% of refinery mixed liquid C₆-C₉ streams (apart from naphtha) 0-25% naphtha, 15-65% triptane, with RON 93-100, MON 80-98, and RVP 40-80kPa, with 1-30% olefins and 2-30% aromatics.

25. Use according to any one of claims 2 to 19 wherein said composition comprises (by volume) 8-18% triptane, 10-50% e.g. 25-40% of total component (b) mixture, 5-40% e.g. 20-35% of total aromatics mixture, 15-30% of total olefinic mixture and 0-15% total oxygenate.

26. Use according to any one of claims 2 to 19 wherein said composition comprises (by volume) 20-40% triptane, 8-55% of the total component (b) mixture, 5-25% total aromatics mixture, and 10-55% total olelin mixture.

27. Use according to any one of claims 2 to 19 wherein said composition comprises (by volume) 40-55% triptane, 5-30% total component (b) mixture, 0-10% total aromatic mixture, 10-45% olefinic mixture and 0-15% oxygenates, with the total of oxygenates (if any) and olefinic mixture of 20-45%.

28. Use according to any one of claims 2 to 19 wherein said composition comprises (by volume) 55-70% triptane, 10-45% total component b, and 0-10% total aromatics Mixture, and 0-30% total olefinics mixtures, especially 55-70% triptane, 10-25% total component (b), 0 or 0.5-5% total aromatics mixture and 15-30% total olefinic mixture.

29. Use according to any one of claims 2 to 19 wherein said composition has a ROAD Index, which is the average of MON and RON, of 85.5-88.5, and comprises (by volume) 8-30% triptane and 10-50% total component (b) mixture, 5-30% total olefins and 10-40% total aromatics.

30. Use according to any one of claims 2 to 19 wherein said composition has a ROAD Index of 88.5-91.0 and comprises (by volume) 5-25% triptane, 20-45% total component (b) mixture, 1-25% total olefins, and 10-35% e.g. 10-20% or 20-35% total aromatics.

31. Use according to any one of claims 2 to 19 wherein said composition has a ROAD Index of 91.0-94.0, and comprises (by volume) 5-65% triptane and 5-40% total component (b) mixture, 1-30% total olefins and 5-55% total aromatics.

32. Use according to any one of claims 2 to 19 wherein said composition has a ROAD Index of 94-97.9, and comprises (by volume) 20-65% triptane, 5-15% total olefins, 5-20% total aromatics and 5-50% total component (b) mixture.

33. Use according to any one of claims 2 to 19 wherein said composition comprises (by volume) 15-35% triptane, 0-18.5% olefin, 5-40% aromatics and 25-65% saturates and has less than 1% benzene.

34. Use according to any one of claims 2 to 19 wherein said composition comprises (by volume) 40-65% triptane, 5-18.5% olefins, 5-28% aromatics and 35-55% saturates and less than 1% benzene.

35. Use according to any one of claims 2 to 34 wherein said motor gasoline additive is an anti-oxidant, corrosion inhibitor, anti-icing additive, engine detergent additive or anti-static additive, or mixture thereof.

36. Use according to claim 35 wherein the additive is an antioxidant

37. Use according to any one of claims 2 to 30 wherein the composition contains the hydrocarbon of formula I in an amount of up to 40% by volume.

38. Use according to claim 37 wherein the composition also comprises at least one of an olefin of 5-10 carbon atoms, aromatic compound in amount of 1-28% or contains less than 5% (by volume) of benzene.

39. Use according to claim 37 or claim 38 wherein the composition comprises said olefin and 1-35% aromatics by volume.

40. Use according to any one of claims 37-39 wherein the composition comprises at least 8% of triptane, component (b) comprising said hydrocarbon of 5 to 10 carbon atoms, and a liquid alkene of 5-10 carbon atoms, and optionally butane.

41. Use according to any one of claims claim 37- 40 wherein the composition comprises (by volume) 10-40% triptane and less than 5% benzene, and has a Reid Vapour Pressure at 37.8°C measured according to ASTMD323 of 30-120kPa.

42. Use according to any one of claims claim 37-41 wherein the composition comprises at least one of isomerate, alkylate, and straight run gasoline, which contains component (b).

43. Use according to any one of claims claim 37- 42 wherein the composition also comprises at least one saturated aliphatic hydrocarbon having 4-6 carbons which has a boiling point at atmospheric pressure at least 30°C lower than the hydrocarbon of formula I.

44. A use as claimed in any one of the preceding claims in which the compound of formula I is triptane.

Ansprüche

1. Verwendung einer Verbindung der Formel I,

        R-CH₂CH(CH₃)-C(CH₃)₂-CH₃     I

worin R Wasserstoff oder Methyl ist, in einem bleifreien Motorenbenzin mit einer MOZ von wenigstens 80 und weniger als 98 zur Verminderung von Abgasemissionen bei dessen Verbrennung.

2. Verwendung gemäß Anspruch 1, worin das bleifreie formulierte Motorenbenzin mit einer MOZ von 80 bis weniger als 98 eine Grundmischzusammensetzung mit einer Motoroctanzahl (MOZ) von wenigstens 80 umfasst, die als Bestandteil (a) wenigstens 5 % (in Volumen der Gesamtzusammensetzung) wenigstens eines Kohlenwasserstoffs mit der folgenden Formel I

        R-CH₂-CH(CH₃)-C(CH₃)₂-CH₃     I

worin R Wasserstoff oder Methyl ist, und als Bestandteil (b) wenigstens einen gesättigten flüssigen aliphatischen Kohlenwasserstoff mit 4 bis 12 Kohlenstoffatomen und wenigstens einen Motorenbenzinzusatz umfasst, der ausgewählt ist aus Antioxidantien, Korrosionsinhibitoren, Enteisungszusätzen, Motordetergentzusätzen, antistatischen Zusätzen, Metalldeaktivatoren, Oberflächenzündungsinhibitoren, Verbrennungswirkstoffen, Ventilschutzzusätzen und färbenden Mitteln.

3. Verwendung gemäß Anspruch 1 zur Verminderung von Emissionen beim Kaltstart eines Verbrennungsmotors mit Fremdzündung.

4. Verwendung gemäß einem der vorhergehenden Ansprüche zur Verminderung von Emissionen von wenigstens einem von Kohlendioxid, Kohlenmonoxid, Stickoxide, Gesamtluftgifte und Gesamtkohlenwasserstoffe.

5. Verwendung gemäß Anspruch 4 zur Verminderung von Kohlendioxidemissionen.

6. Verwendung gemäß einem der Ansprüche 2 bis Anspruch 5, worin besagte Zusammensetzung einen MOZ-Wert von 80 bis weniger als 98 hat und besagter gesättigter Kohlenwasserstoff 4 bis 10 Kohlenstoffatome hat.

7. Verwendung gemäß Anspruch 6, worin das Benzin als Bestandteil (a) wenigstens 8 Vol.-% Triptan umfasst und besagter gesättigter Kohlenwasserstoff 5 bis 10 Kohlenstoffatome hat.

8. Verwendung gemäß einem der Ansprüche 2 bis 7, worin Bestandteil (b) enthalten ist in wenigstens einem von Isomerat, Alkylat, Straight-run-Benzin, leichtes Reformat, leichtes Hydrocrackbenzin und Flugmotorenalkylat.

9. Verwendung gemäß Anspruch 8, worin besagte Zusammensetzung wenigstens 8 Vol.-% Triptan umfasst und worin Bestandteil (b) wenigstens eines ist von Isomerat, Alkylat, Flugmotorenalkylat und Straight-run-Benzin und wenigstens einen gesättigten flüssigen aliphatischen Kohlenwasserstoff mit 5-10 Kohlenstoffatomen umfasst.

10. Verwendung gemäß einem der Ansprüche 2 bis 9, worin besagte Zusammensetzung wenigstens einen gesättigten aliphatischen Kohlenwasserstoff mit 4-6 Kohlenstoffatomen umfasst, der einen niedrigeren Siedepunkt als Triptan hat und eine Motoroctanzahl höher 88 hat.

11. Verwendung gemäß einem der Ansprüche 2 bis 10, worin besagte Zusammensetzung wenigstens einen gesättigten aliphatischen Kohlenwasserstoff mit 5-10 Kohlenstoffatomen umfasst, der einen höheren Siedepunkt als Triptan hat und eine Motoroctanzahl höher 92 hat.

12. Verwendung gemäß einem der Ansprüche 2 bis 11, worin besagte Zusammensetzung wenigstens ein Olefin, das ein Alken mit 5-10 Kohlenstoffatomen ist, mit einem MOZ-Wert von 70-90 in einer Menge von 1-30%, vorzugsweise 5-20% (in Volumen) umfasst.

13. Verwendung gemäß einem der Ansprüche 2 bis 12, worin besagte Zusammensetzung wenigstens eines von katalytisch gecracktem Benzin, Steamcrackbenzin, C₆ Bisomer, katalytischem Polymerat und Dimat umfasst.

14. Verwendung gemäß Anspruch 13, worin besagte Zusammensetzung katalytisch gecracktes Benzin umfasst.

15. Verwendung gemäß einem der Ansprüche 2 bis 14, worin besagte Zusammensetzung auch wenigstens eine aromatische Verbindung mit einem MOZ-Wert von 90-110 in einer Menge von 2-40 %, speziell 3-28 % (in Volumen) umfasst.

16. Verwendung gemäß einem der Ansprüche 2 bis 15, worin besagte Zusammensetzung auch wenigstens eine aromatische Verbindung umfasst, zugegeben als Einzelverbindungen oder zugegeben als ein Aromatengemisch, das aus katalytisch reformiertem oder gecrackten Benzin, erhalten aus Schwernaphtha, hergestellt wurde.

17. Verwendung gemäß einem der Ansprüche 2 bis 16, worin besagte Zusammensetzung auch wenigstens einen sauerstoffhaltigen Octanzahlverbesserer mit einem MOZ-Wert von wenigstens 96-105 in einer Menge von 1-25 % (in Volumen) umfasst.

18. Verwendung gemäß einem der Ansprüche 2 bis 17, worin besagte Zusammensetzung einen Reid-Dampfdruck bei 37,8 °C, gemessen gemäß ASTM D323, von 40 - 100 kPa hat.

19. Verwendung gemäß einem der Ansprüche 2 bis 18, worin besagte Zusammensetzung folgendes Kriterium erfüllt

worin Atom H:C der Bruch aus Wasserstoff zu Kohlenstoff in den Kohlenwasserstoffen in der Zusammensetzung ist, oxy der molare Anteil an sauerstoffhaltiger Komponente, wenn vorhanden, in der Zusammensetzung bedeutet, Netto-Verbrennungswärme die Energie ist, die aus dem Verbrennen von 1 lb (454 g) Gewicht an Brennstoff (gasförmig) in Sauerstoff, um gasförmiges Wasser und Kohlendioxid zu ergeben, ausgedrückt in Btu/Ib-Einheiten [MJ/kg mal 430,35], gewonnen wird, und y wenigstens 350, insbesondere 350-440 ist und ROAD der Durchschnitt von Motoroctanzahl und Research-Octanzahl ist.

20. Verwendung gemäß einem der Ansprüche 2 bis 19, worin besagte Zusammensetzung (in Volumen) 10-90 % Triptan, 10-80 % Bestandteil (b), 0-25 % Naphtha, 0-15 % Butan, 0-20 % Olefin, 3-28 % Aromaten und 0-25 % sauerstoffhaltige Komponente umfasst.

21. Verwendung gemäß einem der Ansprüche 2 bis 19, worin besagte Zusammensetzung 5-20 % Aromaten und 5-18,5 % Olefine (in Volumen) umfasst.

22. Verwendung gemäß einem der Ansprüche 2 bis 19, worin besagte Zusammensetzung (in Volumen) 8-65 % Triptan, speziell 15-35 %, 0,1-30%, wie 2-25 % Olefine, speziell 3-14 %, und 5-35 % Aromaten, 5-50 % Gemische von Bestandteil (b), sauerstoffhaltige Komponenten in einer Menge von weniger als 3 % und weniger als 1,5 % Benzen, z. B. 0,1-1%, umfasst und einen ROZ-Wert von 97-99, einen MOZ-Wert von 87-90 und einen ROAD-Wert von 92-94,5 hat.

23. Verwendung gemäß einem der Ansprüche 2 bis 19, worin besagte Zusammensetzung (in Volumen) 5-25 % Triptan, 5-15 % Olefine, 15-35 % Aromaten und 40-65 % Bestandteil (b), insbesondere 15-25 % Triptan, 7-15 % Olefine, 15-25 % Aromaten und 45-52 % Gemisch von Bestandteil (b) umfasst und einen ROZ-Wert von 96,5-97,5 hat.

24. Verwendung gemäß einem der Ansprüche 2 bis 19, worin besagte Zusammensetzung (in Volumen) 1-15 % Butan, 0-20 % MTBE, 20-80 % gemischte flüssige C₆-C₉-Raffinerieläufe (außer Naphtha), 0-25 % Naphtha, 15-65 % Triptan umfasst, mit einer ROZ von 93-100, MOZ von 80-98 und einem RVP von 40-80 kPa, mit 1-30 % Olefinen und 2-30 % Aromaten.

25. Verwendung gemäß einem der Ansprüche 2 bis 19, worin besagte Zusammensetzung (in Volumen) 8-18 % Triptan, 10-50 %, z. B. 25-40 % Gesamtgemisch von Bestandteil (b), 5-40 %, z. B. 20-35 % Gesamtaromatengemisch, 15-30 % Gesamtolefingemisch und 0-15 % gesamte sauerstoffhaltige Komponente umfasst.

26. Verwendung gemäß einem der Ansprüche 2 bis 19, worin besagte Zusammensetzung (in Volumen) 20-40 % Triptan, 8-55 % Gesamtgemisch von Bestandteil (b), 5-25 % Gesamtaromatengemisch und 10-55 % Gesamtolefingemisch umfasst.

27. Verwendung gemäß einem der Ansprüche 2 bis 19, worin besagte Zusammensetzung (in Volumen) 40-55 % Triptan, 5-30 % Gesamtgemisch von Bestandteil (b), 0-10 % Gesamtaromatengemisch, 10-45 % Olefingemisch und 0-15 % sauerstoffhaltige Komponenten umfasst, wobei die Gesamtheit von sauerstoffhaltigen Komponenten (wenn vorhanden) und Olefingemisch 20-45 % beträgt.

28. Verwendung gemäß einem der Ansprüche 2 bis 19, worin besagte Zusammensetzung (in Volumen) 55-70 % Triptan, 10-45 % Gesamtbestandteil (b) und 0-10 % Gesamtaromatengemisch und 0-30 % Gesamtolefingemische, speziell 55-70 % Triptan, 10-25 % Gesamtbestandteil (b), 0 oder 0,5-5 % Gesamtaromatengemisch und 15-30 % Gesamtolefingemisch umfasst.

29. Verwendung gemäß einem der Ansprüche 2 bis 19, worin besagte Zusammensetzung einen ROAD-Index, der der Durchschnitt von MOZ und ROZ ist, von 85,5-88,5 hat und (in Volumen) 8-30 % Triptan und 10-50 % Gesamtgemisch von Bestandteil (b), 5-30 % Gesamtolefine und 10-40 % Gesamtaromaten umfasst.

30. Verwendung gemäß einem der Ansprüche 2 bis 19, worin besagte Zusammensetzung einen ROAD-Index von 88,5-91,0 hat und (in Volumen) 5-25 % Triptan, 20-45 % Gesamtgemisch von Bestandteil (b), 1-25 % Gesamtolefine und 10-35%, z. B. 10-20 % oder 20-35 % Gesamtaromaten umfasst.

31. Verwendung gemäß einem der Ansprüche 2 bis 19, worin besagte Zusammensetzung einen ROAD-Index von 91,0-94,0 hat und (in Volumen) 5-65 % Triptan und 5-40 % Gesamtgemisch von Bestandteil (b), 1-30 % Gesamtolefine und 5-55 % Gesamtaromaten umfasst.

32. Verwendung gemäß einem der Ansprüche 2 bis 19, worin besagte Zusammensetzung einen ROAD-Index von 94-97,9 hat und (in Volumen) 20-65 % Triptan, 5-15 % Gesamtolefine, 5-20 % Gesamtaromaten und 5-50 % Gesamtgemisch von Bestandteil (b) umfasst.

33. Verwendung gemäß einem der Ansprüche 2 bis 19, worin besagte Zusammensetzung (in Volumen) 15-35 % Triptan, 0-18,5 % Olefin, 5-40 % Aromaten und 25-65 % gesättigte Kohlenwasserstoffe umfasst und weniger als 1 % Benzen enthält.

34. Verwendung gemäß einem der Ansprüche 2 bis 19, worin besagte Zusammensetzung (in Volumen) 40-65 % Triptan, 5-18,5 % Olefine, 5-28 % Aromaten und 35-55 % gesättigte Kohlenwasserstoffe und weniger als 1 % Benzen umfasst.

35. Verwendung gemäß einem der Ansprüche 2 bis 34, worin besagter Motorenbenzinzusatz ein Antioxidans, Korrosionsinhibitor, Enteisungszusatz, Motordetergentzusatz oder antistatischer Zusatz oder ein Gemisch davon ist.

36. Verwendung gemäß Anspruch 35, worin der Zusatz ein Antioxidans ist.

37. Verwendung gemäß einem der Ansprüche 2 bis 30, worin die Zusammensetzung den Kohlenwasserstoff der Formel I in einer Menge von bis zu 40 Vol.-% enthält.

38. Verwendung gemäß Anspruch 37, worin die Zusammensetzung auch wenigstens eines von einem Olefin mit 5-10 Kohlenstoffatomen, einer aromatischen Verbindung in einer Menge von 1-28 % umfasst oder weniger als 5 % (in Volumen) Benzen enthält.

39. Verwendung gemäß Anspruch 37 oder Anspruch 38, worin die Zusammensetzung besagtes Olefin und 1-35 Vol.-% Aromaten umfasst.

40. Verwendung gemäß einem der Ansprüche 37-39, worin die Zusammensetzung wenigstens 8 % Triptan, Bestandteil (b), umfassend besagten Kohlenwasserstoff mit 5 bis 10 Kohlenwasserstoffatomen, und ein flüssiges Alken mit 5-10 Kohlenstoffatomen und wahlweise Butan umfasst.

41. Verwendung gemäß einem der Ansprüche 37-40, worin die Zusammensetzung (in Volumen) 10-40 % Triptan und weniger als 5 % Benzen umfasst und einen Reid-Dampfdruck bei 37,8 °C, gemessen gemäß ASTMD323, von 30-120 kPa hat.

42. Verwendung gemäß einem der Ansprüche 37-41, worin die Zusammensetzung wenigstens eines von Isomerat, Alkylat und Straight-run-Benzin, das Bestandteil (b) enthält, umfasst.

43. Verwendung gemäß einem der Ansprüche 37-42, worin die Zusammensetzung auch wenigstens einen gesättigten aliphatischen Kohlenwasserstoff mit 4-6 Kohlenstoffatomen umfasst, der einen um wenigstens 30 °C niedrigeren Siedepunkt bei Atmosphärendruck als der Kohlenwasserstoff der Formel I hat.

44. Eine Verwendung, wie in einem der vorhergehenden Ansprüche beansprucht, bei der die Verbindung der Formel I Triptan ist.

Revendications

1. Utilisation d'un composé répondant à la formule I,

        R-CH₂-CH(CH₃)-C(CH₃)₂-CH₃     I

   dans laquelle R est un atome d'hydrogène ou un groupe méthyle dans une essence moteur sans plomb de IO moteur d'au moins 80 et inférieur à 98 pour réduire les émissions de gaz d'échappement lors de la combustion de celle-ci.

2. Utilisation selon la revendication 1, dans laquelle l'essence moteur formulée sans plomb ayant un IO moteur de 80 à moins de 98 comprend une composition mélangée de base ayant un indice d'octane (IO) moteur d'au moins 80 comprenant comme composant (a) : au moins 5 % (en volume de la composition totale) d'au moins un hydrocarbure répondant à la formule suivante I

        R-CH₂-CH(CH₃)-C(CH₃)₂-CH₃     I

   dans laquelle R est un atome d'hydrogène ou un groupe méthyle et comme composant (b) : au moins un hydrocarbure aliphatique liquide saturé comportant de 4 à 12 atomes de carbone, et au moins un additif pour essence moteur choisi parmi les antioxydants, les inhibiteurs de corrosion, les additifs antigivrage, les additifs détergents moteurs, les additifs antistatiques, les désactivateurs métalliques, les inhibiteurs d'allumage en surface, les agents améliorant la combustion, les additifs antiévidement de siège de soupape et les agents colorants.

3. Utilisation selon la revendication 1, pour réduire les émissions lors du démarrage à froid d'un moteur à combustion à allumage par étincelle.

4. Utilisation selon l'une quelconque des revendications précédentes, pour réduire les émissions d'au moins l'un des éléments suivants : le dioxyde de carbone, le monoxyde de carbone, les oxydes d'azote, les toxiques de l'air totaux et les hydrocarbures totaux.

5. Utilisation selon la revendication 4, pour réduire les émissions de dioxyde de carbone.

6. Utilisation selon l'une quelconque des revendications 2 à 5, dans laquelle ladite composition a une valeur IO moteur de 80 à moins de 98 et l'hydrocarbure saturé comporte de 4 à 10 atomes de carbone.

7. Utilisation selon la revendication 6, dans laquelle l'essence comprend comme composant (a) au moins 8 % en volume de triptane et ledit hydrocarbure saturé comporte de 5 à 10 atomes de carbone.

8. Utilisation selon l'une quelconque des revendications 2 à 7, où le composant (b) est contenu dans au moins l'un des éléments suivants : l'isomérate, l'alkylat, l'essence de distillation directe, le réformat fluide, l'hydrocraquat fluide et l'alkylat d'aviation.

9. Utilisation selon la revendication 8, dans laquelle ladite composition comprend au moins 8 % en volume de triptane et dans laquelle le composant (b) est au moins l'un des éléments suivants : l'isomérate, l'alkylat, l'alkylat d'aviation et l'essence de distillation directe et comprend au moins un hydrocarbure aliphatique liquide saturé comportant 5 à 10 atomes de carbone.

10. Utilisation selon l'une quelconque des revendications 2 à 9, dans laquelle ladite composition comprend au moins un hydrocarbure aliphatique saturé comportant 4 à 6 atomes de carbone, qui a un point d'ébullition inférieur au triptane et a un indice d'octane moteur supérieur à 88.

11. Utilisation selon l'une quelconque des revendications 2 à 10, dans laquelle ladite composition comprend au moins un hydrocarbure aliphatique saturé comportant 5 à 10 atomes de carbone, qui a un point d'ébullition supérieur au triptane et a un indice d'octane moteur supérieur à 92.

12. Utilisation selon l'une quelconque des revendications 2 à 11, dans laquelle ladite composition comprend au moins une oléfine qui est un alcène de 5 à 10 atomes de carbone, avec une valeur IO moteur de 70 à 90 à en une quantité de 1 à 30 %, de préférence de 5 à 20 % (en volume).

13. Utilisation selon l'une quelconque des revendications 2 à 12, dans laquelle ladite composition comprend au moins l'un des éléments suivants : l'essence de craquage catalytique, l'essence de craquage à la vapeur, le bisomère en C₆, le polymérate catalytique et le dimate.

14. Utilisation selon la revendication 13, dans laquelle ladite composition comprend l'essence de craquage catalytique.

15. Utilisation selon l'une quelconque des revendications 2 à 14, dans laquelle ladite composition comprend également au moins un composé aromatique de valeur IO moteur de 90 à 110, en une quantité de 2 à 40 %, spécialement 3 à 28 % (en volume).

16. Utilisation selon l'une quelconque des revendications 2 à 15, dans laquelle ladite composition comprend également au moins un composé aromatique ajouté comme composé simple ou ajouté comme mélange d'aromatiques fabriqué à partir d'essence de reformage ou de craquage catalytique obtenue à partir de naphta lourd.

17. Utilisation selon l'une quelconque des revendications 2 à 16, dans laquelle ladite composition comprend également au moins un intensificateur d'octane oxygéné de valeur IO moteur d'au moins 96 à 105 en une quantité de 1 à 25 % (en volume).

18. Utilisation selon l'une quelconque des revendications 2 à 17, dans laquelle ladite composition a une pression de vapeur selon Reid à 37,8° C mesurée en conformité avec ASTM D323 de 40 à 100 kPa.

19. Utilisation selon l'une quelconque des revendications 2 à 18, dans laquelle ladite composition satisfait le critère suivant

   dans lequel Atome H:C est la fraction d'hydrogène au carbone dans les hydrocarbures dans la composition, oxy signifie la fraction molaire de composé oxygéné, s'il y en a, dans la composition, la chaleur nette de combustion est l'énergie dérivée du brûlage de 454 g (1 livre) en poids de carburant (sous forme gazeuse) dans l'oxygène pour donner de l'eau et du dioxyde de carbone gazeux exprimée en unités MJ/kg fois 430,35[Btu/livre], et y est d'au moins 350 en particulier 350 à 440 et ROAD est la moyenne de l'indice d'octane moteur et de l'indice d'octane recherche.

20. Utilisation selon l'une quelconque des revendications 2 à 19, dans laquelle ladite composition comprend (en volume) 10 à 90 % de triptane, 10 à 80 % de composant (b), 0 à 25 % de naphta, 0 à 15 % de butane, 0 à 20 % d'oléfine, 3 à 28 % d'aromatiques et 0 à 25 % de composé oxygéné.

21. Utilisation selon l'une quelconque des revendications 2 à 19, dans laquelle ladite composition comprend 5 à 20 % d'aromatiques et 5 à 18,5 % d'oléfines (en volume).

22. Utilisation selon l'une quelconque des revendications 2 à 19, dans laquelle ladite composition comprend (en volume) 8 à 65 % de triptane, spécialement 15 à 35 %, 0,1 à 30 % tel que 2 à 25 % d'oléfines, spécialement 3 à 14 % et 5 à 35 % d'aromatiques, 5 à 50 % de mélanges de composants (b), de composés oxygénés en quantité inférieure à 3 %, et moins de 1,5 % de benzène, par exemple 0,1 à 1 %, et ayant un IO recherche de 97 à 99, un IO moteur de 87 à 90 et des valeurs de ROAD de 92 à 94,5.

23. Utilisation selon l'une quelconque des revendications 2 à 19, dans laquelle ladite composition comprend (en volume) 5 à 25 % de triptane, 5 à 15 % d'oléfines, 15 à 35 % d'aromatiques et 40 à 65 % de composants (b), en particulier 15 à 25 % de triptane, 7 à 15 % d'oléfines, 15 à 25 % d'aromatiques et 45 à 52 % de mélange de composant (b) et d'une valeur IO recherche de 96,5 à 97,5.

24. Utilisation selon l'une quelconque des revendications 2 à 19, dans laquelle ladite composition comprend (en volume) 1 à 15 % de butane, 0 à 20 % de MTBE, 20 à 80 % de coupes (à l'exception de naphta) en C₆ à C₉ liquides mélangées de raffinerie, 0 à 25 % de naphta, 15 à 65 % de triptane, avec un IO recherche de 93 à 100, un IO moteur de 80 à 98 et une pression de vapeur selon Reid de 40 à 80 kPa, avec 1 à 30 % d'oléfines et 2 à 30 % d'aromatiques.

25. Utilisation selon l'une quelconque des revendications 2 à 19, dans laquelle ladite composition comprend (en volume) 8 à 18 % de triptane, 10 à 50 % par exemple 25 à 40 % de mélange de composant (b) total, 5 à 40 % par exemple 20 à 35 % de mélange d'aromatiques total, 15 à 30 % de mélange oléfinique total et 0 à 15 % de composés oxygénés totaux.

26. Utilisation selon l'une quelconque des revendications 2 à 19, dans laquelle ladite composition comprend (en volume) 20 à 40 % de triptane, 8 à 55 % de mélange de composant (b) total, 5 à 25 % de mélange d'aromatiques total et 10 à 55 % de mélange d'oléfines total.

27. Utilisation selon l'une quelconque des revendications 2 à 19, dans laquelle ladite composition comprend (en volume) 40 à 55 % de triptane, 5 à 30 % de mélange de composant (b) total, 0 à 10 % de mélange d'aromatiques total, 10 à 45 % de mélange oléfinique et 0 à 15 % de composés oxygénés, avec un total de composés oxygénés (s'il y en a) et de mélange oléfinique de 20 à 45 %.

28. Utilisation selon l'une quelconque des revendications 2 à 19, dans laquelle ladite composition comprend (en volume) 55 à 70 % de triptane, 10 à 45 % de composant (b) total et 0 à 10 % de mélange d'aromatiques total et 0 à 30 % de mélange oléfinique total, spécialement 55 à 70 % de triptane, 10 à 25 % de composant (b) total, 0 ou 0,5 à 5 % de mélange d'aromatiques total et 15 à 30 % de mélange oléfinique total.

29. Utilisation selon l'une quelconque des revendications 2 à 19, dans laquelle ladite composition a un indice ROAD, qui est la moyenne de IO moteur et IO recherche, de 85,5 à 88,5, et comprend (en volume) 8 à 30 % de triptane et 10 à 50 % de mélange de composant (b) total, 8 à 30 % d'oléfines totales et 10 à 40 % d'aromatiques totaux.

30. Utilisation selon l'une quelconque des revendications 2 à 19, dans laquelle ladite composition a un indice ROAD de 88,5 à 91,0 et comprend (en volume) 5 à 25 % de triptane, 20 à 45 % de mélange de composant (b) total, 1 à 25 % d'oléfines totales et 10 à 35 % par exemple 10 à 20 % ou 20 à 35 % d'aromatiques totaux.

31. Utilisation selon l'une quelconque des revendications 2 à 19, dans laquelle ladite composition a un indice ROAD de 91,0 à 94,0, et comprend (en volume) 5 à 65 % de triptane et 5 à 40 % de mélange de composant (b) total, 1 à 30 % d'oléfines totales et 5 à 55 % d'aromatiques totaux.

32. Utilisation selon l'une quelconque des revendications 2 à 19, dans laquelle ladite composition a un indice ROAD de 94 à 97,9 et comprend (en volume) 20 à 65 % de triptane, 5 à 15 % d'oléfines totales, 5 à 20 % d'aromatiques totaux et 5 à 50 % de mélange de composant (b) total.

33. Utilisation selon l'une quelconque des revendications 2 à 19, dans laquelle ladite composition comprend (en volume) 15 à 35 % de triptane, 0 à 18,5 % d'oléfines, 5 à 40 % d'aromatiques et 25 à 65 % de composés saturés et comporte moins de 1 % de benzène.

34. Utilisation selon l'une quelconque des revendications 2 à 19, dans laquelle ladite composition comprend (en volume) 40 à 65 % de triptane, 5 à 18,5 % d'oléfines, 5 à 28 % d'aromatiques et 35 à 55 % de saturés et moins de 1 % de benzène.

35. Utilisation selon l'une quelconque des revendications 2 à 34, dans laquelle ledit additif d'essence pour moteur est un antioxydant, un inhibiteur de corrosion, un additif antigivrage, un additif détergent pour moteur ou un additif antistatique, ou un mélange de ceux-ci.

36. Utilisation selon la revendication 35, dans laquelle l'additif est un antioxydant.

37. Utilisation selon l'une quelconque des revendications 2 à 30, dans laquelle la composition contient l'hydrocarbure répondant à la formule I en une quantité allant jusqu'à 40 % en volume.

38. Utilisation selon la revendication 37, dans laquelle la composition comprend également au moins l'un des éléments suivants : une oléfine de 5 à 10 atomes de carbone, un composé aromatique en une quantité de 1 à 28 % ou contient moins de 5 % (en volume) de benzène.

39. Utilisation selon la revendication 37 ou 38, dans laquelle la composition comprend ladite oléfine et 1 à 35 % d'aromatiques en volume.

40. Utilisation selon l'une quelconque des revendications 37 à 39, dans laquelle la composition comprend au moins 8 % de triptane, le composant (b) comprenant ledit hydrocarbure de 5 à 10 atomes de carbone, et un alcène liquide de 5 à 10 atomes de carbone, et facultativement du butane.

41. Utilisation selon l'une quelconque des revendications 37 à 40, dans laquelle la composition comprend (en volume) 10 à 40 % de triptane et moins de 5 % de benzène, et a une pression de vapeur selon Reid à 37,8° C mesurée en conformité avec ASTM D323 de 30 à 120 kPa.

42. Utilisation selon l'une quelconque des revendications 37 à 41, dans laquelle la composition comprend au moins l'un des éléments suivants : l'isomérat, l'alkylat et l'essence de distillation directe, qui contient le composant (b).

43. Utilisation selon l'une quelconque des revendications 37 à 42, dans laquelle la composition comprend également au moins un hydrocarbure aliphatique saturé comportant 4 à 6 atomes de carbone qui a un point d'ébullition à pression atmosphérique d'au moins 30° C inférieur à celui de l'hydrocarbure répondant à la formule I.

44. Utilisation selon l'une quelconque des revendications précédentes, dans laquelle le composé répondant à la formule I est le triptane.