Patent GB-780276-A (GB)
Title: Cycloalkylaromatic sulphonates and lubricating oils containing same
Inventor: BOISSELET LEON
IPC: C07C309/25
Filed: 1955-04-01
Abstract: Dispersing and detergent agents for lubricating oils are described, having the general formula: <FORM:0780276/III/1> where N is a naphthenyl radical, Ar is an aromatic hydrocarbon radical, R1 is hydrogen or an alkyl radical or 1 or 2 carbon atoms, R2 is hydrogen or an alkyl radical of from 8 to 18 carbon atoms, R3 is an alkyl radical of from 8 to 18 carbon atoms, and X is a metal other than an alkali metal.  The naphthenyl radical N may be a cyclohexane, methylcyclohexane, dimethylcyclohexane, cyclopentane or methyl cyclopentane radical, Ar may be a benzene, naphthalene or diphenyl radical, X may be strontium, calcium, magnesium, zinc, barium, tin, chromium, iron, cobalt or nickel, and alkyl radicals containing 8 to 18 carbon atoms may be 2-ethylhexyl, dodecyl, palmityl and stearyl groups.  Examples of the compounds are given.  The compounds are readily soluble in lubricating oils and may be used singly or in admixture in proportions of from 0.5 per cent to 7 per cent by weight.  A naphthenic lubricating oil containing 2 per cent of zinc palmityl-cyclohexylbenzene sulphonate is described.ALSO:The invention comprises cycloalkylaromatic sulphonates of the general formula: <FORM:0780276/IV (a)/1> where N is a naphthenyl radical, Ar is an aromatic hydrocarbon radical, R1 is hydrogen or an alkyl radical of 1 or 2 carbon atoms, R2 is hydrogen or an alkyl radical of from 8 to 18 carbon atoms, R3 is an alkyl radical of from 8 to 18 carbon atoms, and X is a metal other than an alkali metal.  The naphthenyl radical N may be a cyclohexane, methylcyclohexane, dimethylcyclohexane, cyclopentane or methyl cyclopentane radical, Ar may be a benzene, naphthalene or diphenyl radical, X may be magnesium, calcium, strontium, zinc, barium, tin, chromium, iron, cobalt or nickel, and alkyl radicals of 8 to 18 carbon atoms may be 2-ethylhexyl, dodecyl, palmityl and stearyl groups.  The compounds are prepared by condensing an aromatic hydrocarbon with a cycloaliphatic alcohol or a cycloalkene in the presence of boron fluoride to form a naphthenyl aromatic hydrocarbon, condensing the latter with an aliphatic alcohol containing from 8 to 18 carbon atoms in the presence of boron fluoride and a dehydrating agent, sulphonating the alkylnaphthenyl-aromatic hydrocarbon so formed with concentrated sulphuric acid or oleum, and effecting salification of the sulphonic acid formed with the carbonate of a metal other than an alkali metal. When R1 is an alkyl group of 1 or 2 carbon atoms, an aromatic hydrocarbon substituted by such an alkyl group (e.g. toluene or ethyl benzene) is used as starting material. After alkylation of the naphthenyl aromatic hydrocarbon, the product may be fractionally distilled under reduced pressure and any unreacted naphthenyl aromatic hydrocarbon recycled to the alkylation.  Individual isomers of the alkyl naphthenyl aromatic hydrocarbon may be separated by fractional distillation.  After the sulphonation, the product may be separated by the addition of aqueous hydrochloric acid to the reaction mixture and decantation of the sulphonic acid layer, which is then treated with the metal carbonate.  Alternatively, the sulphonation reaction mixture may be treated directly with the metal carbonate. The metal sulphonate may be recrystallized from aqueous methanol or boiling water.  In examples: (1) benzene and cyclohexanol are treated with BF3 and P2O5 to yield cyclohexylbenzene and dicyclohexylbenzene, the former is treated with 2-ethylhexyl alcohol to yield (2-ethylhexyl)-cyclohexylbenzene which is sulphonated and reacted with calcium carbonate to give calcium (2-ethylhexyl)-cyclohexylbenzene sulphonate; from cyclohexylbenzene in an analogous manner there are prepared, (2) dodecyl-cyclohexyl-benzene and thence magnesium dodecyl-cyclohexylbenzene sulphonate, (3) palmityl-cyclohexylbenzene and zinc palmityl-cyclohexylbenzene sulphonate, (4) stearylcyclohexylbenzene and barium stearyl-cyclohexylbenzene sulphonate, (5) strontium (2-ethylhexyl) - cyclohexylbenzene sulphonate, and (6) di-(2-ethylhexyl)-cyclohexylbenzene and calcium 3 : 5 - di - (2 - ethylhexyl) - 1 - cyclohexylbenzene - 2 - sulphonate; (7) cyclohexylmethylbenzene and dicyclohexylmethylbenzene are obtained from cyclohexanol and toluene, the cyclohexylmethylbenzene being converted to zinc methyl-palmitylcyclohexylbenzene sulphonate; similarly (8) calcium ethyl-dodecylcyclohexylbenzene sulphonate is prepared from cyclohexylethylbenzene obtained together with dicyclohexylethylbenzene from cyclohexanol and ethylbenzene; (9) barium stearyl-cyclohexylnaphthalene sulphonate is prepared from 2-cyclohexylnaphthalene obtained from cyclohexanol and naphthalene; and (10) p-cyclohexyldiphenyl, prepared from cyclohexanol and diphenyl, is reacted with palmityl alcohol to give a mixture of p-cyclohexyl-p1-palmityl-diphenyl, p - cyclohexyl - o,p1 - dipalmityl - diphenyl and p - cyclohexyl - o1,p1 - dipalmityldiphenyl, the p - cyclohexyl - p1 - palmityl - diphenyl being converted to zinc palmity-cyclohexyldiphenyl sulphonate.  The compounds of the invention are used as dispersing and detergent agents for lubricating oils (see Group III).