Lead-Free Aviation Fuel

Abstract

Lead-free aviation fuel composition with a MON greater than 100, made up of a major component of a fuel made from Avgas and a minor component of at least two compounds from the group of esters of at least one mono-or poly-carboxylic acid and at least one mono- or polyol, anhydrides of a least one mono- or poly-carboxylic acid, preferably aromatic ethers at a level of at least 5% w/w and ketones at a level of more than 10% w/w.

1 . Lead-free aviation fuel composition, with an MON greater than 100, comprising a major proportion of an Avgas base type fuel, and a minor proportion of at least two compounds, of the group constituted by esters of at least one mono or polycarboxylic acid and at least one mono alcohol or one polyol, by anhydrides with at least one mono or polycarboxylic acid, by aromatic ethers, with a content greater than 5% by weight and constituted by ketones with a content greater than 10% by weight, as well as their mixtures. 
     
     
         2 . Composition according to  claim 1 , characterized in that the ester is obtained from saturated mono or dicarboxylic acids comprising 1 to 10 carbon atoms, and preferably 1 to 6 carbon atoms with an alcohol comprising 1 to 10 carbon atoms. 
     
     
         3 . Composition according to  claim 1 , characterized in that the anhydride is obtained from mono or dicarboxylic acids comprising 1 to 10 carbon atoms, which can be cyclic or linear, optionally substituted by alkyl groups in linear, branched or cyclic form. 
     
     
         4 . Composition according to  claim 1 , characterized in that the ether comprises at least one aromatic ring substituted by at least one ether group comprising 1 to 10 carbon atoms. 
     
     
         5 . Composition according to  claim 1 , characterized in that the ketone comprises 3 to 10 carbon atoms per linear carbon chain, optionally substituted by alkyl groups in linear, branched or cyclic form. 
     
     
         6 . Composition according to  claim 1 , characterized in that it contains up to 30% of at least two compounds, in the aviation fuel. 
     
     
         7 . Composition according to  claim 1 , characterized in that the ester content varies from 5 to 30%. 
     
     
         8 . Composition according to any one of the preceding  claim 1 , characterized in that the anhydride content varies from 5 to 25%. 
     
     
         9 . Composition according to  claim 1 , characterized in that the aromatic ether content varies from 5 to 30% by weight, and more preferentially between 5 and 15% by weight in a mixture with at least one second compound. 
     
     
         10 . Composition according to  claim 1 , characterized in that the ketone content varies from 10 to 25% by weight. 
     
     
         11 . Composition according to  claim 1 , characterized in that it comprises 5 to 25% by weight of a first compound and 25 to 5% by weight of a second compound. 
     
     
         12 . Composition according to  claim 1 , characterized in that it contains less than 3.5% of at least one optionally alkyl-substituted aromatic amine, preferably from 0.5 to 3% by weight. 
     
     
         13 . Composition according to  claim 1 , characterized in that the aromatic amine comprises at least one amine group linked to at least one aromatic ring, optionally substituted by at least one alkyl with 1 to 10 carbon atoms. 
     
     
         14 . Composition according to  claim 1 , characterized in that it comprises 25 to 30% by weight of at least two ester, anhydride, ketone or ether type compounds in combination with 0.5 to 3% by weight of aromatic amine. 
     
     
         15 . Composition according to  claim 1 , characterized in that the ester is chosen from the methyl, ethyl, propyl, butyl, dimethyl, diethyl, isopropyl, isobutyl and tertiobutyl acetates, propionates, butyrates, pentanoates and carbonates; with tert-butyl acetate, methyl pivalate and diethyl carbonate being preferred. 
     
     
         16 . Composition according to  claim 1 , characterized in that the anhydride is chosen from the acetic, propionic, butyric, valeric acid anhydrides, but also maleic and succinic acid anhydrides; with pivalic anhydride being preferred. 
     
     
         17 . Composition according to  claim 1 , characterized in that the ether is chosen from the group constituted by the diaryl ethers and the alkylphenyl ethers, the alkyl group comprising 1 to 10 carbon atoms in linear or branched form, preferably methylphenyl ether or anisole, ethylphenyl ether or phenetole, propylphenyl ether, butylphenyl ether, isopropylphenyl ether, isobutylphenyl ether; with phenetole being more particularly preferred. 
     
     
         18 . Composition according to  claim 1 , characterized in that the ketone is chosen from the symmetric or asymmetric alkyl ketones, from the group constituted by dimethyl ketone, diethyl ketone, dipropyl ketone, dibutyl ketone, diisobutyl ketone, dipentyl ketone, methylethylketone, methylpropyl ketone, ethylpropyl ketone, methylbutyl ketone, methylisobutyl ketone, ethylbutyl ketone, ethylisobutyl ketone, propylbutyl ketone, propylisobutyl ketone, isopropylbutyl ketone; with methylisobutyl ketone being preferred. 
     
     
         19 . Composition according to  claim 13 , characterized in that the aromatic amine is chosen from the group constituted by the amines comprising 1 to 5 carbon atoms per carbon chain and at least one aromatic ring substituted by at least one alkyl comprising 1 to 5 carbon atoms in ortho (o), meta (m) or para (p) position in relation to the amine. 
     
     
         20 . Composition according to  claim 19  characterized in that the aromatic amine is chosen from the group constituted by phenylamine, the o,m,p-tert-butylphenylamines, o,m,p-methylphenylamines, o,m,p-ethylphenylamines, o,m,p-propylphenylamines, o,m,p-isopropylphenylamines, o,m,p- isobutylphenylamines, 3,5-dimethylphenylamine, 3,4-dimethylylphenylamine, 3,5-diethylphenylamine, 3,4- diethylphenylamine, 3,5-dipropylphenylamine, 3,4- dipropylphenylamine, 3,5-methylethylphenylamine, 3,4- methylethylphenylamine, 3,5-dimethylphenylamine and 3,4- dimethylphenylamine. 
     
     
         21 . Composition according to  claim 20  characterized in that the amines chosen are p-methylphenylamine, m-methylphenylamine or m-toluidine, p-ethylphenylamine, m-ethylphenylamine, m-isopropylphenylamine and m-tert-butylphenylamine; with m-toluidine being preferred. 
     
     
         22 . Composition according to  claim 1 , characterized in that said aviation fuel based fuel comprises 25 to 80% by weight of an aviation alkylate, 30 to 5% by weight of aviation reformate and 5 to 25% by weight of isopentane. 
     
     
         23 . Composition according to  claim 1 , characterized in that said aviation fuel based reformate contains more than 35% by weight of toluene preferably between 45 and 70% by weight. 
     
     
         24 . Composition according to  claim 1 , characterized in that said aviation fuel based alkylate contains more than 40% by weight of 2,2,4 and 2,3,3 trimethylpentanes, preferably between 40 and 65% by weight. 
     
     
         25 . Composition according to  claim 1 , characterized in that a lead alkyl derivative is added up to a maximum of 0.14 of lead per litre of aviation fuel; preferably up to 0.08 g. 
     
     
         26 . Composition according to  claim 1 , characterized in that it contains 5% to 20% of mono or dialkyl ethers such as diisopropyl ether, ethyltert-butyl ether, methyltert-butyl ether, dimethyl ether and tertamyl methylether.