REODORANT COMPOSITION

Abstract: A reodorant additive for use in a liquid petroleum fuel, for example a middle distillate fuel such as a heating oil or a diesel oil, comprises a fuel-soluble ester having up to 25 carbon atoms. The ester may be in admixture with a perfume oil.

Description: REODORANT COMPOSITION This invention relates to the use of reodorants in liquid petroleum fuels, for example middle distillate fuels such as heating oils. Middle distillates are fuels obtained in the refining of crude oil as the fraction between the lighter kerosene and jet fuels fraction and the heavy fuel oil fraction. They are typically used as diesel fuel and heating oil. A problem with a middle distillate fuel is its odour which, depending on the source of the oil, may range from acceptable to totally unacceptable to those in the vicinity of the oil such as the user. There is therefore a need to provide ways of reducing or neutralising the odour of such oils. It is known to incorporate esters into fuel oils. For example, US-A-4 353 710 describes adding ester fuel extenders to hydrocarbon fuels heavier than gasoline. Also, GB-A-2 115 004 describes an additive composition for hydrocarbon fuels comprising a mixture that includes an aliphatic C^-s ester, the additive being for improving fuel efficiency and providing cleaner burning. The invention is concerned with use of reodorant additives for oils such as the above, the additives being or including esters and being, if desired, used with synergistic effect in combination with perfume oils and without disadvantageous effect in combination with components commonly used as additives to heating oils such as combustion improvers and metal deactivators. The invention provides, in a first aspect, the use in a liquid petroleum fuel of an additive comprising a first-mentioned ester that is soluble in the fuel, the ester having up to 25 carbon atoms and being of a carboxylic acid and an alcohol, wherein the additive masks or reduces the odour of the fuel oil. The finding that the afore-mentioned ester is capable of masking or reducing the odour of the fuel oil is surprising because the odour of the latter is generated by the effect of many components. Thus, one would not expect to be able to mask or reduce a fuel oil odour using an ester according to this invention. If desired, the ester may be used in admixture with a perfume oil, comprising one or more aldehydes, ketones, alcohols and esters, and possibly terpenes wherein any ester in the perfume oil is different from the first-mentioned ester. The concentration of ester and perfume oil together in the fuel required to produce a particular reodorant effect may be much less than the concentration of either ester or perfume oil alone in the fuel required to produce a similar reodorant effect, i.e. the ester and perfume oil may act synergistically. The findings of this invention can be economically significant when the perfume oil is much more expensive than the ester. Thus, the cost of materials to produce a given reodorant effect would, using this invention, then be lower than when a perfume oil were used as sole reodorant. In a second aspect, this invention provides a fuel comprising in admixture a major proportion of a liquid petroleum fuel and a minor proportion of a reodorant additive comprising a first-mentioned ester that is soluble in the fuel and having up to 25 carbon atoms and being of a carboxylic acid and an alcohol, in admixture with a perfume oil comprising one or more aldehydes, ketones, alcohols and esters wherein any ester in the perfume oil is different from the first-mentioned ester. The first-mentioned ester in this invention has, as stated above, up to 25 carbon atoms. Preferably it has up to 20 carbon atoms such as 4 to 14, in particular, 6 to 12 carbon atoms. The carboxylic acid, which preferably has from 1 to 4 carbon atoms, may for example be a saturated aliphatic monocarboxylic acid. The alcohol, which preferably has from 3 or 4 to 10 carbon atoms, may for example be a saturated aliphatic onohydric alcohol. Preferred esters are C 4 _ 10 alkyl esters of acetic acid. Single esters or mixtures thereof may be used such as n-heptyl acetate or an equimolecular mixture of n-hexyl acetate and n-octylacetate. The esters, which may be known in the art, may for example be made by reacting a carboxylic acid with the appropriate alcohol. By "perfume oil" in this specification is any substance, other than the first-mentioned ester, having an odour that is capable, when used alone, of masking an odour of a liquid petroleum fuel to be treated. The perfume oil does not necessarily impart a sweet or pleasant odour to the fuel. As stated above, such an oil may comprise one or more of aldehydes, ketones, esters and alcohols. It may, for example be a blend including all of the above and may contain other constituents such as organo-nitrogen compounds, lactones, ethers (including acetals and ketals) , hydrocarbons, and other organic materials. Perfume oils may for example be proprietary blends. Examples of perfume oils are proprietary blends produced by Bush, Boake and Allen and other proprietary fumes. In the practice of the invention, the fuel may be any liquid petroleum product between LPG and heavy fuel oil, for example boiling in the range of 100*C to 500*C (e.g. 150*C to 400*C) . It is preferably a diesel oil or a heating oil, a diesel oil being a middle distillate fuel such as according to an ASTM Specification and a heating oil being a middle distillate fuel for use in space heating, for example according to ASTM Specification D-396-80. It may, if desired, include other components such as a combustion improver or a metal deactivator or both, examples of which are known in the art. Further, a flow improver such as known in the art may also be included. A combustion improver is a compound such as an organometallic compound which, in use of a heating oil, supports combustion of a heating oil droplet by releasing chemically active metal at the flame temperature. In this way, a catalytic surface is provided to still unburnt hydrocarbons resulting in higher conversion of generated soot. An example of such combustion improvers are organometallic sandwich compounds such as dicyclopentadienyliron, commonly known as ferrocene, wherein each of the cyclopentadiene rings may be unsubstituted or may be independently substituted with one or more alkyl, cycloalkyl, aryl or heterocyclic groups. A metal deactivator is a component for deactivating metals which would otherwise cause the oil to deteriorate over a period of storage. Such deterioration, which is of unstable materials such as unsaturated hydrocarbons in the oil, may result in sediments and gums being formed which, in use of the oil in a heating installation, affect overall performance by blocking fuel filters and, when deposited in the burner nozzle, by disturbing the fuel spray pattern. A cause of such deterioration is the presence of copper arising from its use as a construction material in heating installations; such SUBSTITUTE SHEET copper catalyses the deterioration processes. An example of a metal deactivator is a compound containing secondary amine functionality, allowing circulation of metal ions, and sufficiently large hydrophobic side chain(s) to provide solubility in the fuel. A specific example is Mannich condensation product in the form of an alkylated phenol having a secondary amine side chain. Examples of flow improvers known in the art are ethylene/vinyl ester copolymers, fumarate/vinyl ester copolymers, phthalic acid derivatives, ethylene propionates and terpolymers including ethylene and vinyl esters. If desired, the fuel may include further components. Some examples are dispersants and detergents such as a polyisobutylene succinic anhydride polyamine blend known in the art, and macrocyclic compounds such as described in US-A-4,637,886 and US-A-4,880,923 which are incorporated herein by reference. The ester, or ester and perfume oil, may be provided in the fuel by addition thereto of a concentrate including the ester, or ester and perfume oil. In a third aspect, the invention provides a reodorant concentrate for addition to a liquid petroleum fuel comprising, in admixture in solution in a solvent therefor, a first-mentioned ester that is soluble in the fuel and having up to 25 carbon atoms and being of a carboxylic acid and an alcohol, in admixture with a perfume oil comprising one or more aldehydes, ketones, alcohols and esters wherein any ester in the perfume oil is different from the first-mentioned ester. The solvent must be compatible with the fuel; examples are aromatic solvents such as those with an average C number of 9. The concentrate may include other components, for example a combustion improver, a metal deactivator, a flow improver, or a dispersant/detergent such as described above. As an exemplary generalisation, the composition of the concentrate may fall within the following ranges where the percentages are weight/weight:ester (1-25%), perfume oil (0.5-25%), combustion improver (1-50%) , metal deactivator (2-25%) , and solvent (25-80%). In all aspects of the invention where the perfume oil is present, the relative proportions of ester and perfume oil may be significant. Thus, the ratio of ester and oil (weight of ester:weight of oil) may be in the range of 1:20 to 20:1, e.g. 5:1 to 20:1. In the first and second aspects where the perfume oil is present the total proportion of ester and perfume oil together may, for example, be up to 500 ppm (weight:weight) , such as 5 ppm to 200 ppm, for example 25 ppm to 200 ppm. The following are examples of the invention. Exa le l Preparation of Concentrate The following components were mixed together in the proportions indicated where all percentages are weight:weight. Proprietary names and/or sources may be given in parentheses. Ester : n-heptyl acetate; V.P. 0.5 kPa at 38'C (9.6%) . SUBSTITUTE Perfume Oil a proprietary perfume oil comprising a mixture including one or more aldehydes, alcohols and esters (1.2%) (ex Bush Boake and Allen; Reference 11598) Combustion ferrocene (3.66%) Improver (ex Pluto) Metal : alkylated phenol with secondary amine side Deactivator chain (10%). Solvent aromatic liquid of average C number 9 (75.54%). Use of Concentrate The above-prepared concentrate (11) was added to a heating oil (2000 1) having an unpleasant odour and thoroughly admixed therewith by shaking to give 500 ppm of the concentrate in the oil, i.e. 48 ppm of ester and 6 ppm of perfume oil. ££§££ Samples of the above-treated heating oil were placed in containers and rated for odour by six people independently on each of five successive days at the same time each day, the containers being kept closed between ratings. Each of the people rated the odour on a scale of 1 to 6 on each of the days: 3 represents a neutral odour; greater than 3 represents an unpleasant odour where a higher number represents a more unpleasant odour; and less than 3 represents a pleasant odour where a lower number represents a more pleasant odour. The average rating was between 2 and 3, showing that the SUBSTITUTESHEET concentrate had completely masked the original unpleasant odour of the heating oil. Example 2 The procedure of Example 1 was repeated with the exception that the perfume oil was a proprietary oil designated as BBA 11597 (ex Bush Boake and Allen) and the heating oil contained, after treatment, 30 ppm of the ester and 6 ppm of the perfume oil. The average rankings for odour were: DAY: 1 2 3 4 5 RANK: 2 2k 2\ 2h 2 Example 3 The procedure of Example 2 was repeated with the exception that the perfume oil was a proprietary oil designated as BBA 11622 (ex Bush Boake and Allen) . The average rankings for odour were: The procedure of Example 2 was repeated with the exception that the perfume oil was a proprietary oil designated as BBA 11621 (ex Bush Boake and Allen) . The average rankings for odour were: DAY: 1 2 3 4 5 RANK: 3 2\ 3 2 2 The above results illustrate the effectiveness of the present invention in masking or rendering pleasant the original unpleasant odour of the heating oil. In each example the perfume oil and ester were each independently unable to mask the original unpleasant smell of the heating oil at the stated concentrations.

Claims: Claims : 1. The use in a liquid petroleum fuel of an additive comprising a first-mentioned ester that is soluble in the fuel, the ester having up to 25 carbon atoms and being of a carboxylic acid and an alcohol, wherein the additive masks or reduces the odour of the fuel oil. 2. The use of claim 1 wherein the ester has from 4 to 14 carbon atoms. 3. The use of either of the preceding claims wherein the carboxylic acid has from 1 to 4 carbon atoms. 4. The use of any of the preceding claims wherein the alcohol has from 3 to 10 carbon atoms. 5. The use of any of the preceding claims wherein the acid is a saturated aliphatic monocarboxylic acid. 6. The use of any of the preceding claims wherein the alcohol is a saturated aliphatic monohydric alcohol. 7. The use of any of the preceding claims wherein the ester is an alkyl ester of acetic acid. 8. The use of any of the preceding claims wherein the fuel is a middle distillate fuel. 9. The use of any of the preceding claims wherein the ester is in admixture with a perfume oil being a reodorant for the fuel, the perfume oil comprising one or more aldehydes, ketones, alcohols and esters wherein any ester in the perfume oil is different from the first-mentioned ester. SUB 10. The use of claim 9 wherein the ratio of ester to perfume oil is in the range of 5:1 to 20:1 (weight:weight) . 11. The use of claim 9 or claim 10 wherein the proportion of ester and perfume oil together in the fuel is in the range of 5 ppm to 200 ppm (weight:weight) . 12. A fuel composition comprising in admixture a major proportion of a liquid petroleum fuel and a minor proportion of a reodorant additive comprising a first-mentioned ester that is soluble in the fuel and having up to 25 carbon atoms and being of a carboxylic acid and an alcohol, in admixture with a perfume oil comprising one or more aldehydes, ketones, alcohols and esters wherein any ester in the perfume oil is different from the first-mentioned ester. 13. The composition of claim 12 wherein the fuel is a middle distillate fuel. 14. A reodorant concentrate for addition to a liquid petroleum fuel comprising, in admixture in solution in a solvent therefor, a first-mentioned ester that is soluble in the fuel and having up to 25 carbon atoms and being of a carboxylic acid and an alcohol, in admixture with a perfume oil comprising one or more aldehydes, ketones, alcohols and esters wherein any ester in the perfume oil is different from the first-mentioned ester. 15. The invention of any of claims 12 to 14 wherein the ester has from 4 to 14 carbon atoms. 16. The invention of any of claims 12 to 15 wherein the carboxylic acid has from 1 to 4 carbon atoms. 17. The invention of any of claims 12 to 16 wherein the alcohol has from 3 to 10 carbon atoms. 18. The invention of any of claims 12 to 17 wherein the acid is a saturated aliphatic monocarboxylic acid. 19. The invention of any of claims 12 to 18 wherein the alcohol is a saturated aliphatic monohydric alcohol. 20. The invention of any of claims 12 to 19 wherein ester is an alkyl ester of acetic acid. ET

Inventors: GSCHWENDTNER WOLFGANG WILHELM, HART RICHARD, HEIN ANDREAS, HIRSCH PETER, GSCHWENDTNER, WOLFGANG, WILHELM, JOSEF, HART, RICHARD, HEIN, ANDREAS, HIRSCH, PETER
Applicants: EXXON CHEMICAL LTD, EXXON CHEMICAL PATENTS INC, EXXON CHEMICAL LIMITED, EXXON CHEMICAL PATENTS INC.
Application year: 1991
Main classification: C10L1
IPC codes: C10L1, C11B9, F02B3