GB961407A - Improved leaded motor fuel - Google Patents

Abstract

A gasoline composition contains from 3 to 65% by weight of methyl benzenes having from 1 to 4 methyl groups, and from 0.5 to 6.0 gms., preferably 1.05 to 3.17 gms., of lead per U.S. gallon in the form of tetra-alkyl lead in which at least 25% of the alkyl groups are methyl groups. The tetra-alkyl lead compound may be tetramethyl lead either alone or in admixture with one or more of tetraethyl, methyl triethyl, dimethyldiethyl, and trimethyl ethyl leads, while the list of optional additives also includes tetrapropyl lead and tetraphenyl lead. The tetra-alkyl lead compounds may be present as a physical mixture, or as the "chemical" mixture produced when a mixture of tetramethyl and tetraethyl lead is subject to the action of a catalyst such as an aluminium halide, e.g. AlCl3, an alkyl aluminium halide, e.g. ethyl aluminium sesquihalide, or an alkyl lead halide, e.g. triethyl lead chloride, whereby a random redistribution of the methyl and ethyl radicals takes place producing all possible combinations. Numerous specific mixtures of tetra-alkyl lead compounds are given. Of the monoto tetramethyl substituted benzenes those with higher degrees of substitution are preferred, although all possible compounds are specified. The base fuels may be straight run, catalytically or thermally cracked, alkylates or isomerized materials, and may contain benzene and other aromatics, many of which are specified in the examples. Other octane improving additives may be present, including methyl cyclopentadienyl manganese tricarbonyl, cyclopentadienyl nickel nitrosyl, manganese pentacarbonyl, iron carbonyl and dicyclopentadienyl iron. Additional antiknock improvers referred to are carboxylic acid esters, e.g. tert.-butyl acetate, and amine salts of organic acids, e.g. isobutylamine isobutyrate, ethyl amine a -a -dimethyl propionate, and n-propyl amine propionate. Organohalide scavengers may also be used, those referred to being aliphatic and/or aromatic halohydrocarbons, haloalkyl ethers, and halohydrogen and halonitro compounds, specific mention being made of ethylene dibromide, ethylene dichloride, dibromotoluene, and 1,2,4-trichlorobenzene. Other additives mentioned are antioxidants, e.g. N,N1 - di - sec - butyl - p - phenylene diamine, p-N-butylamino phenol, 4-methyl-2,6-di - tert. - butyl phenol, and 2,6 - di - tert.-butyl phenol, metal deactivators, e.g. N,N1-disalicylidene - 1,2 - diaminopropane, dyes, phosphorus additives, e.g. tri-(b -chloropropyl) thionophosphate, dimethyltolylphosphate, dimethylxylylphosphate, phenyldimethylphosphate, tricresylphosphate, phenyldicresylphosphate, cresyldiphenylphosphate, and trimethylphosphate, anti-icing agents, e.g. alcohols and salts of dehydroabietylamine, corrosion inhibitors, and detergents.