Patent GB-787459-A (GB)
Title: Improvements in or relating to lubricating oil compositions
IPC: C07C309/62
Filed: 1954-04-13
Abstract: Basic alkaline-earth metal sulphonates are prepared by saponifying a sulphonyl chloride of a saturated hydrocarbon having a molecular weight between 300 and 550 with an aqueous slurry of an alkaline earth metal oxide or hydroxide, the proportions of the sulphonyl chloride, metal oxide or hydroxide and water being such that the ratio of sulphur atoms to metal atoms in the resulting sulphonate is not greater than 1.35 to 1.  The amount of base used is at least sufficient to enable the desired basicity to be obtained and is preferably at least 1.25 times the theoretical quantity.  The actual basicity of the sulphonate formed is determined by the molar ratio of water to base in the slurry.  The basic calcium salts, for example, are obtained when the molar ratio of water to calcium oxide in the slurry is about 10:1 to about 100:1, the higher ratios giving superbasic salts; a ratio below 10:1 results predominantly in neutral salt formation even though excess of the base is present.  In the case of the barium hydroxide slurries, the molar ratio of water to barium hydroxide should be below 9.4 to 1.  The saponification may be effected at about 170-300 DEG  F. under atmospheric or elevated pressure.  The sulphonyl chlorides may be prepared by reacting the hydrocarbon which may be paraffinic or naphthenic, e.g. a white oil, a paraffin wax or a solvent raffinate of a lubricating oil fraction, with sulphur dioxide and chlorine in the presence of actinic light at, for example, 60-200 DEG  F. and, if desired, under raised pressure; a solvent may be present.  The reaction is preferably terminated before all the hydrocarbon has reacted.  The sulphonyl chlorides may be isolated but preferably the product, after degassing, is used directly in the saponification; the sulphonates are then obtained as a solution in the original oil from which, after removal of unchanged base, they may be recovered by extraction with an aqueous alcohol, followed by a naphtha wash of the alcoholic extraction to remove entrained oil, removal of the aqueous alcohol by distillation and extraction of the residue with absolute alcohol. Suitable apparatus is described for the sulpho chlorination and saponification reactions.  Experiments are described wherein (1) a white oil (M.W. 432) and a saturated mineral oil (M.W. 440) are sulpho chlorinated, in some cases using carbon tetrachloride as solvent and the product, diluted or not with a hydrocarbon diluent, is saponified with excess calcium oxide in an aqueous slurry yielding an oil solution of calcium sulphonates which may be extracted with aqueous isopropanol in order to isolate the sulphonates; (2) the white oil sulphonyl chloride of (1) is saponified with an aqueous slurry of barium hydroxide and an oil solution of barium sulphonates having a S : Ba ratio of 0.837 is obtained; (3) several portions of a phenol raffinate of a mineral lube oil are sulpho chlorinated and then, after dilution with an oil, are saponified with aqueous lime slurries of various compositions to yield calcium sulphonates in which the S : Ca ratios range from about 1 to 0.58.  The salts are used as lube-oil additives (see Group III).  Specification 690,046, [Group III], is referred to.ALSO:Lubricating oil compositions comprise a lubricating oil and an oil-soluble alkaline earth metal petroleum sulphonate obtained by saponifying a hydrocarbon sulphonyl chloride, the hydrocarbon radical of which is derived from a saturated hydrocarbon having a molecular weight between about 300 and 550, with an aqueous slurry of an alkaline earth metal oxide or hydroxide, the proportion of sulphonyl chloride, metal base and water being such that the ratio of sulphur atoms to metal atoms in the resulting sulphonate is not greater than 1.35 to 1 (see Group IV (b)).  The sulphonates may be basic, i.e. having a sulphur : metal atom ratio of between about 1.35 and 1 to 1 or superbasic, i.e. a sulphur:metal ratio not greater than 1:1.  The lubricating compositions may contain, as base oil, a mineral lubricating oil or a synthetic oil, e.g. a polymerized alphaolefine, a polyethylene or polypropylene oxide or a synthetic ester-or formal-type lubricating oil and the sulphonate preferably amounts to 0.1-5 per cent of the composition.  A mixture of the basic and super-basic alkaline earth metal sulphonates may be blended with the oil.  Oil concentrates containing 20-75 per cent of the metal sulphonate may first be prepared.  The hydrocarbon sulphonyl chloride may be derived from a white oil, a paraffin wax, a solvent raffinate of a lubricating oil fraction or other paraffinic or naphthenic oil. Examples describe the detergent and corrosion inhibiting characteristics of about 1 per cent solution in a S.A.E. 30 oil of calcium petroleum sulphonates derived from a phenol raffinate of a lubricating oil fraction and having S:Ca ratios varying from about 1 to 0.58.  A basic barium salt of a white oil sulphonic acid in which the S:Ba ratio is 0.837 is also mentioned. Specification 690,046 is referred to.