GB829635A - Improved fuel compositions - Google Patents

Abstract

A lead-scavenging and anti-knock fuel comprises gasoline containing not more than 2 theories of halohydrocarbon scavenger in which is dissolved or dispersed (a) not less than 5 theories with respect to the lead of certain boron compounds, and (b) not less than 0.5 theories with respect to the lead of sulphur and/or phosphorous compounds. The boron compound is defined as any boron compound soluble or dispersable in the base fuel other than boronic or borinic acids of the general formula R-B(OH)2 and <FORM:0829635/III/1> respectively, wherein R is a cyclic radical with a cyclic carbon attached directly to the boron, or their anhydrides or salts. Examples of the boron compounds are boric acid, alkali metal and alkaline earth metal salts of oxy-acids of boron; trialkyl esters, acid esters, cyclic and dicyclic esters of boric acid, especially ethyl 2-methyl pentane 2,4 diolborate, alkyl boronic and dialkyl borinic acids and their esters, particularly the cyclic esters formed from alkyl boronic acids with 6 to 10 carbon atoms and alkane diols with 2 to 8 carbon atoms alkanolamine esters of boronic and borinic acids, borazoles and boric acid polyesters. Suitable sulphur compounds added to the fuel preferably in the proportions of 10-15 theories, for example, oil-soluble sulphur compounds of sweetened Middle East crude oils contain thiophene and its derivatives, such as dialkyl thiophene, e.g. 2 methyl thiophene, 3 ethylthiophene, 2,4 dimethylthiophene or benzthiophene. The phosphorus compounds which may be added to the fuel in the ratio of 0.5 to 1.5 theories in preference to the sulphur compounds or as a mixture with the sulphur compounds are oilsoluble organic esters of oxyacids and thioacids of phosphorus, such as ortho-, pyro-, or metaphosphoric acids, and phosphorous or hypophosphorous acid, the alkyl-phosphonic and alkyl phosphinic acids and their thioanalogues, for example, tri-methyl phosphates and phosphites, triphenyl orthophosphate, tricresylthiophosphate, dicresyl propyl phosphonate. The gasoline portion of the fuel which may be a straight-run, catalytically or thermally reformed, or catalytically or thermally cracked gasoline suitable for use in spark-ignited internal combustion engines and can contain benzene, toluene, alcohol or ethers should not contain more than 0.2 theories of halohydrocarbon lead scavengers, for example ethylene dichloride and ethylene dibromide, and is preferably free from such compounds. Lead containing anti-knock compounds such as tetraethyl lead, ethyl trimethyl lead, diethyl dimethyl lead, triethyl methyl lead and tetramethyl lead are present in the fuel in the proportions, for tetra ethyl lead from 0.5 to 5 cc. per Imperial gallon. Specifications 722,537, 722,538, 794,380, 818,047, 818,727 and 829,634 also are referred to.