Patent GB-742765-A (GB)
Title: A process for the preparation of oil-soluble basic alkaline earth metal petroleum sulphonates
IPC: C07C309/62
Filed: 1953-10-02
Abstract: A process for the preparation of oil-soluble basic alkaline earth metal petroleum sulphonates comprises mixing a solution of oil-soluble alkali metal or ammonium petroleum sulphonates in a petroleum fraction with a water-soluble and oil-soluble oxygen-containing organic liquid which contains not more than six carbon atoms per molecule, contacting the resulting mixture or a separated portion thereof consisting of oil-soluble alkali metal or ammonium petroleum sulphonates dissolved in said organic liquid, with a water-soluble inorganic alkaline earth metal salt and with an amount of water sufficient to cause the formation of two phases, namely an organic phase and an aqueous phase, separating the two phases thus formed, adding to the organic liquid phase a basic alkaline earth metal compound and water in an amount sufficient to provide a concentration of residual water in the mixture after the said oxygen-containing organic liquid is subsequently removed therefrom of at least 2 per cent by weight, removing from the mixture the said oxygen-containing organic solvent, and dehydrating the mixture so formed.  The basic alkaline earth metal compound can, as a modification, be added after the removal of the oxygen-containing liquid.  Suitable oxygen-containing organic liquids are the alkanols and alkanones containing 4 to 6 carbon atoms.  Specially preferred are alkanols containing 4 or 5 carbon atoms and alkanones containing 4 or 5 carbon atoms, e.g. tertiary butyl and amyl alcohols and methyl ethyl ketone.  In a preferred method a solution of 20 per cent to 50 per cent, preferably 30 to 40 per cent, of the alkali metal sulphonate in the petroleum fraction is dissolved in an alkanol or alkanone and the solution contacted continuously at up to 170 DEG F., preferably at 110 DEG  to 130 DEG  F., with at least one and preferably 1.5 to 2 molar equivalents (according to the equation 2RSO3M + CaCl2-->Ca(RSO3)2 + 2MCl) of the water-soluble inorganic alkaline earth metal salt such as calcium chloride.  Sufficient water to form two phases is added and the non-aqueous phase comprising an oil solution of the neutral alkaline earth metal sulphonate dissolved in the alkanol or alkanone is continuously separated and to it 0.75 to 1.5 molar equivalents (according to the equation Ca(RSO3)2 + Ca(OH)2-->2RSO3CaOH) of an alkaline earth metal oxide or hydroxide and a substantial amount of water are added.  The alkanol or alkanone is continuously removed from the resulting mixture, and the remaining solution is dehydrated and filtered. The solution of neutral alkaline earth metal petroleum sulphonates generally is diluted with an amount of petroleum fraction such that the final solution of the basic alkaline earth metal petroleum sulphonates in the petroleum hydrocarbon has a sulphate ash content of from about 9 to 11 per cent by weight.  The petroleum hydrocarbons from which the solution of ammonium or alkali metal sulphonates employed may be prepared include particularly those which possess lubricating properties and are of the mixed type containing naphthenic type hydrocarbons.  Prior to sulphonation the oil may be treated with sulphur dioxide, furfural or other selective solvents.  A suitable oil is obtained by the solvent extraction of distillates having a viscosity of 60 S.S.U. at 210 DEG F. derived from an 80:20 by weight mixture of Poso and Coalinga California crudes.  Sulphonation may be effected by reaction with fuming sulphuric acid followed by addition of water and separation of the oil layer.  As an alternative, after the sulphonation the reaction mixture is diluted with a naphtha solvent, e.g. of boiling range 190 DEG  to 220 DEG  F., precipitated tarry sludge is removed and the naphtha-oil-sulphonic acid solution is neutralized with a slight excess of an aqueous alkali-metal hydroxide solution.  The mixture separates into two layers, and the oil layer is removed and freed from naphtha solvent.  To remove inorganic salts and some unsulphonated oil, the crude oil solution of alkali metal sulphonates is contacted with a minor proportion of water and a minor proportion of an oxygen-containing organic liquid containing not more than 6 carbon atoms per molecule, the proportions, temperature and pressure being adjusted to yield a three-phase mixture comprising an oil-rich phase, an organic solvent-rich phase and a water-rich phase.  The solvent-rich phase is separated and can be used directly as starting material in the process of the invention. Tertiary butyl alcohol is a preferred solvent.  A continuous process is described (with flow sheet) of the treatment of sodium sulphonates from a raffinate containing about 65 per cent of paraffins and naphthenes, 20 per cent monocyclic aromatics, 13 per cent dicyclic aromatics and 2 per cent resins and polycyclic aromatics (all by weight) sulphonated and purified as in the second method described above, the neutral alkaline earth metal salt being prepared by treatment with 1.5 to 2 euqivalents of a solution of an inorganic salt, preferably calcium chloride in a countercurrent contacting system.  In the conversion to the basic salt a lime slurry containing 0.75 to 1.5 molar equivalents of calcium hydroxide based on the original sodium sulphonate is used. The product is flashed at 220 DEG  to 250 DEG  F. to remove the butyl alcohol and some water and at 290 DEG  to 310 DEG  F. to remove the remaining water, and is then filtered.  A more detailed example describes the production of an oil solution of a basic calcium petroleum sulphonate having a base number of 25.15 and a sulphate ash content of 10.5 per cent by weight.ALSO:A lubricating oil composition comprises a major proportion of a lubricating oil and a minor proportion of certain oil-soluble basic alkaline earth metal petroleum sulphonates (for preparation of the sulphonates (see Group IV(b)).  An example describes the production of an oil solution of a basic calcium petroleum sulphonate.