GASOLINE COMPOSITION

Abstract: The invention provides a method of highlighting the purity of a gasoline composition comprising a major amount of a substantially colourless gasoline having a Research Octane No. of at least 95, a Motor Octane No. of at least 85, density at 15 DEG C in the range 720 to 775 kg/m<3>, sulphur content not greater than 50 mg/kg (ppmw), oxygenate content 0 to 15 % v/v contributing to oxygen content not greater than 2.7 % w/w, olefins content 0 to 18 % v/v, aromatics content 15 to 35 % v/v giving overall benzene content not greater than 1.0 % v/v, the balance of the gasoline being saturated hydrocarbon, which method comprises imparting a translucent blue hue to the gasoline composition by incorporating an effective concentration of blue dye therein; gasoline compositions comprising the substantially colourless gasoline and the blue dye incorporated therein; and a method of influencing motorists to use environmentally advantageous gasoline.

Description: - i - GASOLINE COMPOSITION FIELD OF THE INVENTION This invention relates to gasoline compositions, and more particularly to gasoline compositions having dyes incorporated therein, their preparation and use. BACKGROUND OF THE INVENTION It is known to impart colour to oil products, e.g. hydrocarbon fuels such as gasoline or kerosme (paraffin oil) - see for example The Petroleum Handbook, 5 th Ed., 1966, Page 111 (Shell International Petroleum Company) and Kirk-Othmer, Encyclopedia of Chemical Technology, 3rd Ed., 1980, Vol. 11, Page 669 (Wiley) . Two formerly well known commercial kerosmes containing dyes were "ALADDIN PINK" paraffin and "ESSO BLUE" paraffin (trade marks) . Commercially available base gasolines are generally not colourless, but at least slightly yellow in hue. This background colour affects the appearance of gasoline to which dyes are added (e.g. addition of red or pink dyes tends to produce orange to brown gasoline and addition of blue dyes tends to produce green gasoline), unless sufficiently high concentrations of dye are added to mask the background colour. In these latter instances, the colours are deep and distinctive, but the products are far from brignt and sparkling. SUMMARY OF THE INVENTION It has now been found possible to provide a gasoline having significant environmental benefits when used as fuel m spark-ignition engines, having a translucent blue hue. This translucent blue hue can provide a sparkling visual effect to an observer akin to tnat of spray from a waterfall in a mountain stream against a dear blue sunlit sky. Such a visual effect can serve to highlight the purity of such a gasoline product, and have the surprising environmental benefit of making a potential purchaser more likely to choose to purchase such gasoline than conventional gasoline by subjectively highlighting the purity of the gasoline. According to the present invention therefore there is provided a method of highlighting the purity of a gasoline composition comprising a major amount of a substantially colourless gasoline having a Research Octane No. of at least 95, a Motor Octane No. of at least 85, density at 15°C in the range 720 to 775 kg/m 3 , sulphur content not greater than 50 mg/kg (ppmw) , oxygenate content 0 to 15% v/v contributing to oxygen content not greater than 2.7% w/w, olefms content 0 to 18% v/v, aromatics content 15 to 35% v/v giving overall benzene content not greater than 1.0% v/v, the balance of the gasoline being saturated hydrocarbon, which method comprises imparting a translucent blue hue to the gasoline composition by incorporating an effective concentration of blue dye therein. DETAILED DESCRIPTION OF THE INVENTION Gasolines typically contain mixtures of hydrocarbons boiling in the range from about 30°C to about 230°C, the optimal ranges and distillation curves varying according to climate and season of the year. The hydrocarbons in a gasoline as defined above may conveniently be derived in known manner from straight-run gasoline, synthetically- produced aromatic hydrocarbon mixtures, thermally or catalytically cracked hydrocarbons hydrocracked petroleum fractions or catalytically reformed hydroc rbon and mixtures of these. Oxygenates include alcohols (such as methanol, ethanol, isopropanol, tert.butanol and isobutanol) and ethers, and are preferably etners containing 5 or more carbon atoms per molecule, e.g. methyl tert. butyl ether (MTBE) . The ethers containing 5 or more carbon atoms per molecule may be used in amounts up to 15% v/v, but if methanol is used, it can only be in an amount up to 3% v/v, and stabilisers will be required. Stabilisers may also be needed for ethanol, which may be used up to 5% v/v. Isopropanol may be used up to 10% v/v, tert-butanol up to 7% v/v and isobutanol up to 10% v/v. Gasolines as defined above have been found to be substantially colourless, an alternative description being nearly completely water-white. Gasoline compositions as defined above may variously include one or more additives such as anti-oxidants, corrosion inhibitors, ashless detergents, dehazers and synthetic or mineral oil carrier fluids. Examples of suitable such additives are described generally in US Patent No. 5,855,629. Additive components can be added separately to the gasoline or can be blended with one or more diluents, forming an additive concentrate, and together added to the gasoline. The blue dye can be added to the gasoline independently of other additives, or as a component of such an additive concentrate. The blue dye must be soluble in the gasoline. Very effective blue dyes have been found to have a maximum light absorbance peak in the range 630 to 660 nm, preferably 645 to 655 nm. Light absorbance peaks may conveniently be measured using a Lambda 25 Perkm-Elmer UV-VIS (trade mark 1 spectrometer. Suitable blue dyes may include, for example, DyeGuard Blue 79R ex John Hogg Technical Solutions, Automate Blue 8G ex Morton, and Unisol Liquid Blue A ex UCM. Tne πetncα cf Highlighting of the invention preferably comprises incorporatinα in the gasoline a dyestuff having a maximum light aosorbance peak in the range 630 to 660 nm at a concentration to give a blue colour corresponding in intensity to that achieved by incorporation of DyeGuard Blue 79R at a concentration in the range 3 to 30 ppmv, (parts per million volume/volume) more preferably 5 to 25 ppmv, and very conveniently 5 to 15 ppmv. DyeGuard Blue 79R itself has been found to give very effective results. The appropriate concentration of a chosen dyestuff depends on the intensity of blue colour desired and the nature of the active matter and its concentration in the chosen dyestuff . DyeGuard Blue 79R is sold with a specified active matter content of 48% w/w. Automate Blue 8G is stated to have an active matter content of about 40%w/w. Unisol Liquid Blue A is stated to have active matter content of 50% w/w. The gasoline compositions as defined above themselves form an aspect of the present invention. The present invention thus further provides a gasoline composition which comprises a major amount of a substantially colourless gasoline having a Research Octane No. of at least 95, a Motor Octane No. of at least 85, density at 15°C in the range 720 to 775 kg/m 3 , sulphur content not greater than 50 mg/kg (ppmw) , oxygenate content 0 to 15% v/v contributing to oxygen content not greater than 2.7% w/w, olefms content 0 to 18% v/v, aromatics content 15 to 35% v/v giving overall benzene content not greater than 1.0% v/v, the balance of the gasoline being saturated hydrocarbon, the gasoline composition having a translucent blue hue by incorporation of an effective concentration of blue dye therein. Preferred such gasoline compositions are compositions wherein tne blue dye is a αyestuff nav g a maximum light absorbance peak the range 630 to 660 nm at a concentration to give a blue colour corresponding in intensity to that achieved by incorporation of DyeGuard Blue 79R at a concentration in the range 3 to 30 ppmv, more preferably 5 to 25 ppmv, and very conveniently 5 to 15 ppmv . Preferably the light absorbance maxima for gasoline compositions of the invention within the range 630 to 660 nm, more preferably 645 to 655 nm, are m the range 0.1 to 0.5 absorption units, more preferably 0.11 to 0.48 absorption units, and very conveniently 0.12 to 0.47 absorption units as measured using a Lambda 25 Perkm-Elmer UV-VIS Spectrometer. In preferred gasoline compositions of the invention the translucent blue hue provides a sparkling visual effect to an observer akin to that of spray from a waterfall in a mountain stream against a clear blue sunlit sky. This is very attractive to a potential purchaser and serves to emphasise in the mind the environmental benefits of the gasoline compositions of the invention, which have the potential to reduce emissions of harmful pollutants such as nitrogen oxides and benzene compared with conventional unleaded 95 Research octane gasoline such as that commercially available in The Netherlands in 1998. Accordingly, the present invention further provides a method of influencing motorists to use environmentally advantageous gasoline in vehicles powered by spark-ignition engines which comprise dispensing a gasoline composition of the invention as defined above from a forecourt dispenser associated with a visual display of liquid having a colour corresponding to that of said gasoline composition. b - The visual display may comprise a transparent pipe or chamber in the αelivery system of the forecourt dispenser, so tnat a customer can see the gasoline composition as it passes through the delivery system whilst dispensing the gasoline composition, or it may comprise an enclosed tank containing a sample of the gasoline composition or another liquid (e.g. water, for fire-safety reasons) having substantially the same visual effect as the gasoline composition . The invention will be further understood from the following illustrative examples thereof, in which a substantially colourless gasoline having characteristics within the above ranges was employed in comparison with a conventional high-guality unleaded gasoline according to EK 228:93 as sold m April 1999 by Shell Nederland B.V. These gasolines had the properties as shown in Table 1 following. Table 1 The conventional gasoline, although of high quality, had a noticeable yellow colour. In the examples and comparative examples, DyeGuard Blue 79R ex John Hogg Technical Solutions was used as the blue dye, and light absorbance was measured at 648 nm using a Lambda 25 Perkin-Elmer UV-VIS spectrometer. The blue dye was dispersed homogeneously into samples of the gasolines at various concentrations of active matter, and results obtained are given Table 2 following. Table 2 Examples 1 and 2 were particularly preferred, as they conveyed a visual impression akin to that of spray from a waterfall in a mountain stream against a clear blue sunlit sky . Engine emissions tests were carried out m order to demonstrate the environmental benefits of the gasoline of the SCG of Table 1 in comparison with a blend of conventional unleaded 95 Research octane gasolines commercially available m The Netherlands in 1998 (market gasoline, MG) . The properties of the MG (determined as in Table 1) were as follows: RON 96.0, MON 85.5, density 740 kg/m 3 , sulfur content 95 mg/kg, olefms 11.7% (v/v), aromatics 36.3% (v/v), benzene content 1.78% v/v, oxygen content 0.01% m/m, oxygenate content 0.71% v/v. The MG had a clear yellowish appearance. The emissions tests were carried out on two vehicles, and the results were averaged, in order to give a result indicative of the overall effect possible on large-scale switch-over of use from presently conventional gasoline compositions to those of the present invention. The vehicles were (1) Vauxhall/Opel Vectra with C18 XEL Ecotec 4 cylinder spark-ignition engine of cylinder capacity 1799 cc , bore/stroke 86 mm/81.6 mm and rated power output 115 bhp at 5400 rpm, and (2) Ford Fiesta with DHA 2 ETEC 16 valve 4 cylinder spark-ignition engine of cylinder capacity 1250 cc, bore/stroke 71.9 mm/76.5 mm and rated power output 73.8 bhp at 5200 rpm. Both cars were equipped with standard catalytic convectors . The vehicles were run on a chassis dynamometer following a standard European emissions driving cycle (Directive 91/441/EEC). The cycle used was ECE 15.04 and EUDC with an 11 second idle. Compared with the MG, the SCG gave measured emissions reductions (%w) of 44%w oxiαes of nitrogen and 30%w benzene .

Claims: C L A I M S 1. A method of hignlighting the purity of a gasoline composition comprising a major amount of a substantially colourless gasoline having a Research Octane No. of at least 95, a Motor Octane No. of at least 85, density at 15°C in the range 720 to 775 kg/m 3 , sulphur content not greater than 50 mg/kg (ppmw) , oxygenate content 0 to 15% v/v contributing to oxygen content not greater than 2.7% w/w, olefms content 0 to 18% v/v, aromatics content 15 to 35% v/v giving overall benzene content not greater than 1.0% v/v, the balance of the gasoline being saturateα hydrocarbon, which method comprises imparting a translucent blue hue to the gasoline composition by incorporating an effective concentration of blue dye therein. 2. A method according to Claim 1 which comprises incorporating m the gasoline a dyestuff having a maximum light absorbance peak in the range 630 to 660 nm at a concentration to give a blue colour corresponding in intensity to that achieved by incorporation of DyeGuard Blue 79R at a concentration in the range 3 to 30 ppmv. 3. A method according to Claim 2 wherein said range is 5 to 25 ppmv. 4. A method according to Claim 3 wherein said range is 5 to 15 ppmv. 5. A gasoline composition which comprises a major amount of a substantially colourless gasoline having a Research Octane No. of at least 95, a Motor Octane No. of at least 85, density at 15°C in the range 720 to 775 kg/m 3 , sulphur content not greater than 50 mg/kg (ppmw) , oxygenate content 0 to 15% v/v contributing to oxygen content not greater than 2. w/w, olefms content 0 to 181 v/v, aromatics content 15 to 35% v/v giving overall benzene content not greater than 1.0% v/v, the balance of the gasoline being saturated hydrocarbon, the gasoline composition having a translucent blue hue by incorporation of an effective concentration of blue dye therein. 6. A gasoline composition according to Claim 5 wherein the blue dye is a dyestuff having a maximum light absorbance peak in the range 630 to 660 nm at a concentration to g ve a blue colour corresponding in intensity to that achieved by incorporation of DyeGuard Blue 79R at a concentration in the range 3 to 30 ppmv. 7. A gasoline composition according to Claim 6 wherein said range is 5 to 25 ppmv. 8. A gasoline composition according to Claim 7 wherein said range is 5 to 15 ppmv. 9. A method of influencing motorists to use environmentally advantageous gasoline in vehicles powered by spark-ignition engines which comprises dispensing a gasoline composition according to any one of claims 5 to 8 from a forecourt dispenser associated with a visual display of liquid having a colour corresponding to that of said gasoline composition.

Inventors: MCDONALD CLIVE RICHARD, MCDONALD, CLIVE, RICHARD
Applicants: SHELL INT RESEARCH, SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ B.V.
Application year: 2000
Main classification: C10L1
IPC codes: C10L1, C10L10