| abstract |
An internal-combustion engine fuel comprises hydrocarbons of the gasoline boiling range containing a minor proportion of a tetra-alkyl lead, a minor proportion of a completely esterified ester of an oxyacid of phosphorus or arsenic containing at least one carbocyclic radical and a minor proportion of a halohydrocarbon scavenger. Preferably the organic ester scavenger is derived from phosphorus oxyacids such as ortho-, pyro-or metaphosphoric acid. Suitable esters are the triphenyl-, tricresyl-, tri (4 - ethylphenyl) -, tri (4 - tertiary - butylphenyl)-, trixylenyl-, tri-2-naphthyl-, tri(4-isopropyl-1-naphthyl)-, tribenzyl-, triphenylethyl-, tricyclohexyl-, tri(trichlorophenyl)- and tri(4-chlorobenzyl)-orthophosphates, di-isoamyl cyclohexyl orthophosphate, dibutyl phenyl-orthophosphate, 2-naphthyl diphenyl orthophosphate, 2-naphthyl - 31 - methylphenyl - phenyl - orthophosphate and triphenyl-phosphite. Other compounds are tri-o-, -m- or -p-cresyl arsenite and diethyl phenyl arsonate. The preferred ester is tri-cresyl orthophosphate. Suitable halohydrocarbon scavengers are ethylene dibromide or dichloride, acetylene tetrabromide, 2,2,3-trichlorobutane, 2-chloro-2, 3-dibromobutane, and the dibromotoluenes. The halohydrocarbon scavenger should not comprise more than 90 per cent by weight of the combined scavengers. The preferred range of total scavenger content is from 0.9 to 1.2 theories. Anti-oxidants such as 2, 4-dimethyl-6-tertiary butyl phenol, hydroquinone, 2,6-ditertiary butyl-4-methyl phenol, N-phenol-x-naphthylamine and N, N1-dibutyl-p-phenylene diamine may also be present in the fuel. Any tetra alkyl lead anti-knock agent may be used, such as tetraethyl lead, ethyl trimethyl lead, diethyl-dimethyl lead, triethyl methyl lead and tetramethyl lead. The invention is not applicable to gasolines containing iron carbonyl. The fuels of the invention are compared in tests with fuels containing conventional halohydrocarbon scavengers, and fuels containing oxyacid esters of phosphorus containing no carbocyclic radical. The Provisional Specification refers also to fuels comprising hydrocarbons of the gasoline boiling range containing a small amount of tetraethyl lead and a small amount of an organic ester of an oxy-acid of phosphorus containing at least one carbocyclic radical. The results of tests comparing a gasoline containing 7.2 millilitres of tetraethyl lead and the theoretical equivalent of ethylene dibromide with the same leaded gasoline containing the theoretical equivalent of tri-cresyl-orthophosphate are reported. |