Patent GB-721886-A (GB)
Title: Processes for the preparation of basic alkaline earth metal petroleum sulphonates
IPC: C10M159/24
Filed: 1951-12-31
Abstract: Oil-soluble basic alkaline-earth metal petroleum sulphonates suitable as lubricant additives are prepared by converting an oil-soluble alkali-metal petroleum sulphonate dissolved in a petroleum fraction and contaminated with inorganic salts and/or water-soluble petroleum sulphonates, into the oil-soluble neutral alkaline-earth metal sulphonate by treatment with a water-soluble alkaline earth metal salt and converting the neutral alkaline-earth metal sulphonate into an oil-soluble basic alkaline-earth metal sulphonate by treatment with at least a molar equivalent of a basic inorganic alkaline earth metal compound, calculated on the alkaline earth metal sulphonate present in the petroleum fraction, the solution of the alkali or neutral alkaline earth metal sulphonate in the petroleum fraction being washed with water so as to remove said contaminants before the conversion into the basic alkaline earth metal sulphonate is carried out, the amount of water used being at least 50 per cent, preferably 100 to 500 per cent, by volume based on the volume of the solution of alkali-metal sulphonate in the petroleum fraction; a minor amount of a monohydric alcohol having not more than 12 carbon atoms may be added to the washing water.  The initial petroleum solution of alkali-metal sulphonate is preferably prepared from a petroleum oil having lubricating properties and containing naphthenic hydrocarbons. The oil may be solvent extracted with furfural, sulphur dioxide or other like solvent and the raffinate purified by a sulphuric acid treatment.  The raffinate is sulphonated at about 75 DEG  to 200 DEG F. with fuming sulphuric acid, the product diluted with water, an aqueous sludge phase removed and the oil phase containing desired sulphonic acids neutralized with a basic alkali-metal compound.  The preferred embodiment of the invention comprises simultaneously converting the alkali-metal sulphonate in this oil solution into the neutral alkaline-earth metal sulphonate and washing the solution and thereafter converting the neutral salt into the basic alkaline earth metal salt.  Thus, the sodium sulphonate-oil solution may be contacted at about 200 DEG  F. with the large quantity of wash water specified and with at least a molar equivalent of calcium chloride, preferably two molar equivalents, p  sufficient to convert the sodium sulphonate and sodium sulphate present into the corresponding neutral calcium salts and for a period of time sufficient for substantial conversion to occur, a resulting aqueous phase of pH not greater than 8 is separated, and the oil phase treated at about 200 DEG  F. with a minor amount of water plus at least a molar equivalent of calcium hydroxide based on the calcium sulphonate in the oil phase and preferably with 0.4 to 0.8 molar equivalent of calcium chloride based on amount of sodium sulphonate present originally in the oil solution.  The resulting oil solution of basic calcium sulphonate may be clarified by settling or drying to remove water and filtered. Graphs (not shown) indicate that this filtration is much easier than that required in prior processes wherein there is no washing of the sulphonate-oil solution as specified.  The calcium hydroxide and chloride may be replaced by other basic alkaline earth metal compounds and water-soluble alkaline earth metal salts, including those of barium, strontium and magnesium.  An example is given wherein the initial oil solution of sodium petroleum sulphonates is derived from a lubricating oil of viscosity 400 S.S.U. at 100 DEG F., and the solution contains 13 per cent sodium sulphonates, 5 per cent water, 2 per cent inorganic salts and the remainder unsulphonated oil.  Specification 603,238 is referred to.ALSO:Lubricating oil compositions comprising oil-soluble basic alkaline-earth metal sulphonates are prepared by converting an oil-soluble alkali-metal petroleum sulphonate dissolved in a petroleum fraction and contaminated with inorganic salts and/or water-soluble sulphonates into the oil soluble neutral alkaline-earth metal sulphonate by treatment with a water-soluble alkaline-earth metal salt and converting the neutral alkaline earth-metal sulphonate into the basic alkaline-earth metal salt by treatment with at least a molar equivalent of a basic inorganic alkaline-earth metal compound, calculated on the alkaline-earth metal sulphonate present in the petroleum fraction, the solution of the alkali-metal or neutral alkaline-earth metal sulphonate in the petroleum fraction being washed with water so as to remove said contaminants before the conversion into the basic alkaline-earth metal sulphonate is carried out, the amount of water used being at least 50 per cent, preferably 100 to 500 per cent, by volume based on the volume of the solution of alkali-metal sulphonate in the petroleum fraction; a minor proportion of a monohydric alcohol containing not more than 12 carbon atoms may be present in the wash water.  The initial oil solution of alkali-metal sulphonate may be prepared from a petroleum oil having lubricating properties and containing naphthenic hydrocarbons.  The oil may be solvent extracted with furfural, sulphur dioxide or like solvent and the raffinate purified by sulphuric acid treatment.  The raffinate is then sulphonated with fuming sulphuric acid, diluted with water, the resulting aqueous sludge removed and the oil phase containing sulphonic acids neutralized with a basic alkali-metal compound. The preferred embodiment of the invention comprises simultaneously converting the alkali-metal sulphonates in the oil solution into the neutral alkaline-earth metal sulphonates and washing the solution and thereafter converting the neutral alkaline-earth metal salt into the basic salt.  Thus, the sodium sulphonate-oil solution may be contacted at about 200 DEG F. with the wash water and with at least a molar equivalent of calcium chloride, sufficient to convert the sodium sulphonate and sodium sulphate present into the corresponding neutral calcium salts, for a period of time sufficient for at least 70 per cent conversion to occur, an aqueous phase of pH not greater than 8 is separated and the oil phase treated at about 200 DEG F. with a minor amount of water plus at least a molar equivalent of calcium hydroxide based on the calcium sulphonate in the oil phase and preferably with 0.4 to 0.8 molar equivalent of calcium chloride based on the amount of sodium sulphonate present originally in the oil solution.  The resulting oil solution of basic calcium sulphonate may be clarified by settling or drying to remove water and filtered. Graphs (not shown) illustrate the ease of this filtration compared with that in prior processes wherein the washing step is omitted. The calcium hydroxide and chloride may be replaced by other basic alkaline-earth metal compounds and water-soluble alkaline-earth metal salts including those of barium, strontium and magnesium. An example is given using an initial oil solution of sodium sulphonates derived from a lubricating oil of viscosity 400 S.S.U. at 100 DEG F. and containing 13 per cent sodium sulphonates, 5 per cent water, 2 per cent inorganic salts and the remainder of unsulphonated oil. Specification 603,238 is referred to.