Patent GB-1017980-A (GB)
Title: Lead phosphorodithioates suitable for use as lubricant improving agents
IPC: C07F9/02
Filed: 1964-01-20
Abstract: Compositions for use as lubricant additions comprise a mixture of lead salts of phosphorodithioic acids, which contain only primary aliphatic radicals which may be substituted, both lower (below 5C) and higher (5C and above) aliphatic groups being present in such proportion that an average of at least 8.5C per P atom are present, in clear solution in an oil at concentrations of 20-80% by weight of lead salt. The substituent groups may be Cl, Br, F, NO2, NO, CO, S, ether or ester groups.  The oil may be kerosene, fuel oil, gas oil, dioctyl adipate, dinonyl sebacate, castor oil, olive oil, sesame seed oil or mineral oil, preferably being mineral lubricating oil of viscosity about 80 Saybolt seconds at 100 DEG  F. to 100 Saybolt seconds at 210 DEG  F.; the preferred lead salt content is 40-60% by weight.  The composition is included as an additive in lubricants and as an improving agent for hydrocarbon fuels, e.g. gasoline, fuel oil and gas oil, in amount of 0.1-20% by weight, the bulk of the lubricant being suitable mineral oil, polymerized polyisobutane, polymerized cracked paraffin wax, dioctyl adipate, or natural animal or vegetable oils.  Other known additives may also be present, which include: Ba, Ca, Zn, and Ni diorganophosphorodithioates; phosphorus sulphide treated olefins; sulphurized and sulphur chloride treated olefins; alkyl phenolates; alkyl phenolate sulphides and disulphides; phenolates of phenol aldehyde condensation products; amines such as p-aminophenol; N-alkylated phenylene diamine, and anthranilic acid, and esters thereof; metal salts of P2S5 treated polyethylenes, -propylenes, and -iso-butenes; hindered phenols; organo-boron compounds; organo-phosphites and -phosphates; foam inhibiting silicones; pour depressants; oiliness agents; viscosity index improvers; extreme pressure agents; halogenated aliphatic and cycloaliphatic compounds; chlorinated eicosane; chlorinated cyclohexane; sulphurized esters; dithiocarbamic acid esters and salts; xanthic acid esters and salts; and alcohols.  The latter are particularly preferred, being substituted or unsubstituted aliphatic or cyclo-aliphatic C6 to above C20 alcohols as they markedly improve extreme pressure properties when used together with the lead compositions. Examples are given for the preparation of fine compositions of the invention as about 50% by weight solutions in low viscosity mineral oil. Comparative examples for further compositions are given; being Examples (6) a composition of 50% by weight of lead phosphorodithioates derived from iso-butyl, n-amyl, iso-amyl, and 2-methyl-1-butyl alcohols, having an average of 8.3 C-atoms/P-atom; (7) 50% solution in light oil, of lead phosphorodithioates from alcohols as in (6) in differing proportions, with 8.3 C-atoms/P-atom; (8) as for (6), but derived from iso-butyl alcohols only, giving 8 C-atoms/P-atom; (9) as for (6), but derived from mixed n-amyl, iso-amyl, and 2-methyl-1-butyl alcohols only, giving 10 C-atoms/P-atom; (10) as for (6) but derived from the secondary alcohols, butanol-2 and pentanol-2, and having 8.7 C-atoms/P-atom; (11) and (12) 9.6 and 8.7 C-atoms/P-atom lead salt solutions, derived from mixed 4-methyl-pentanol-2 and isopropanol; (13) lead composition derived from iso-propanol with octanol-2, having 8.5 C-atoms/P-atom. An example for a composition containing the lead phosphorodithioate derived from iso-butyl, n-amyl, iso-amyl, and 2-methyl-1-butyl alcohols with addition of primary isodecanol, used to improve S.A.E. 90 mineral oil is also given.ALSO:The invention comprises a mixture of lead salts of phosphorodithioic acids, of the formula <FORM:1017980/C2/1> wherein R1 and R2 represent optionally substituted higher (5C or above) or lower (below 5C) primary aliphatic radicals, which are both contained in the mixture in such proportion that the average number of carbon atoms therein is at least 8.5 carbons per 1 phosphorus atom. Lower aliphatic groups are suitably iso-butyl, n-butyl, n-propyl, ethyl, or methyl radicals; preferred higher aliphatic groups are n-amyl, primary iso-amyl, neopentyl, and 2-methyl-1-butyl groups, but the following may also be present: n-hexyl, n-heptyl, primary iso-octyl, 2-ethyl primary iso-hexyl, n-nonyl, n-decyl, n-undecyl, lauryl, cetyl, and oleyl. The substituent groups optionally present are: Cl, Br, F, NO2, NO, C = O, S, ether, or ester groups.  The lead salts comprise mixtures of different lead phosphorodithioates, salts prepared from mixtures of different phosphorodithioic acids, and salts of phosphorodithioic acids prepared from mixtures of alcohols, and are prepared by methods appropriate to these three groups, i.e. separate preparation followed by mixture of individual lead phosphorodithioates; separate preparation of individual phosphorodithioic acids, followed by mixing prior to reaction with, e.g. lead monoxide; and reaction of P2S5 with mixed alcohols to give mixed acids which are neutralized with, e.g. lead monoxide.  Also reaction of alkali metal or ammonium salts of the acids with soluble lead salts, or with finely-divided lead may be effected. Examples are given for the preparation of lead salts, by reaction of mixed phosphorodithioic acids with lead monoxide in mineral oil, the acids being prepared by reaction of P2S5 with the following mixtures of alcohols: (1) Isobutyl, n-amyl, iso-amyl, and 2-methyl-n-butyl alcohols, giving a salt mixture of 8.7 C/P atom; (2) as for (1) with different conditions; (3) as for (1) to give a salt mixture having 9.6 C/P atom; (4) n-propyl and iso-octyl alcohol giving a salt mixture having 8.5 C/P atom; (5) as for (1) with different conditions.  Comparative examples are also given for the preparation of the following compounds: (6) as for (1) but giving a salt mixture having 8.3 C/P atom; (7) as for (2) but giving a salt mixture having 8.3 C/P atom; (8) di-iso-butyl phosphorothioic acid lead salt, i.e. 8 C/P atom only; (9) mixed amyl alcohols with no lower alcohols, salt mixture having 10 C/P atom; (10) secondary butanol and pentanol, to give secondary-group-containing salt mixture; (11) 4-methyl pentanol with isopropanol, giving a salt mixture having 9.6 C/P atom; (12) 4-methyl pentanol with isopropanol, giving a salt mixture having 8.7 C/P atom; (13) isopropanol with secondary octanol, to give a salt mixture of 8.5 C/P atom.  The lead salts according to the invention are suitable for use as lubricating oil additives (see Division C5).