Patent GB-822816-A (GB)
Title: Improvements in or relating to method of making oil-soluble sulfonates of metals
IPC: C07C309/62
Filed: 1956-04-05
Abstract: Oil-soluble metal sulphonates are pre<FORM:0822816/IV (a)/1> pared by sulphonating a hydrocarbon oil with oleum, separating the acid oil which contains dissolved sulphonic acids, from excess acid and sludge, neutralizing the acid oil with ammonia, thereby converting the sulphonic acids to ammonium sulphonates and contaminating sulphuric acid to ammonium sulphate, removing said ammonium sulphate, heating the oil and ammonium sulphonates with a basic metal oxide or hydroxide, thereby expelling ammonia and forming the metal sulphonate, and recovering the oil and dissolved metal sulphonate. Specified hydrocarbon oils are those boiling above about 600 DEG  F. such as petroleum fractions or alkylated aromatic hydrocarbons, e.g. benzene, xylene or naphthalene alkylated with long chain olefins having 25-60 carbon atoms.  The separation of acid oil from sludge may be aided by the addition of a hydrocarbon solvent such as petroleum naphtha, benzene, toluene, xylene or cracked or reformed naphthas.  A partitioning solvent, with or without water, is used to separate ammonium sulphate from the ammonium sulphonates.  The ammonium sulphate is precipitated or forms a brine if water is present, and is removed.  The preferred partitioning solvents are soluble in oil but are also appreciably soluble in water such as alcohols and amines containing four to six carbon atoms, e.g. butyl, amyl and hexyl alcohols and triethylamine.  A method of carrying out the process is described in more detail with reference to the accompanying Figure.  Oleum and the hydrocarbon oil are fed to a mixer and thence by way of the recirculating pump 16 and cooling coil 13, and with addition of further oleum by line 15, to a second mixer. The sulphonation mixture is then passed, with further recirculation and cooling and addition of water by line 23 to stop the sulphonation, to the settler.  A hydrocarbon solvent is added by line 24.  In the settler the lower layer of waste acids is drawn off, the upper layer of unreacted oil, oil-soluble sulphonic acids and solvent is passed, with addition of ammonia water by line 28 to a mixer and thence to the solvent stripper 29. From the heated stripper excess ammonia, solvent vapours and steam pass by line 31 to scrubber 33, where they are scrubbed with water, the resultant ammonia water returning to line 28 and the solvent to storage tank 37.  The ammonium sulphonate-oil stream passes from the base of the stripper (a partitioning solvent, e.g. secondary butyl alcohol, being added by line 41) to a mixer and thence to a settler wherein the mixture is allowed to settle into three phases.  The bottom layer comprising mainly aqueous ammonium sulphate is treated with lime and the liberated ammonia is stripped off in stripper 44 and recycled by line 47.  The upper layer which is unsulphonated oil with some ammonium sulphonate and partitioning solvent is treated with lime, heated and stripped free from ammonia, solvent and water which are recycled by line 47.  The oil issuing from the stripper by line 65 is filtered, after the addition of a filter aid by line 68, and stored.  The middle layer containing the ammonium sulphonate is passed to heater 52 and heated with lime introduced by line 53.  The mixture is passed to separator 52a, wherein the aqueous phase is separated and passed by line 52b to stripper 44.  The upper layer in 52a comprising calcium sulphonate, solvent and ammonia is passed to stripper 55 wherein solvent and ammonia are removed by line 56 to line 47 and recycled.  The calcium sulphonate is removed by line 57, treated with a filter aid added by line 60, filtered and stored.  In a modification of the process a partitioning solvent miscible in all proportions with water but which is also a solvent for oil is used, e.g. methyl, ethyl and isopropyl alcohols and water-soluble amines. The ammonium sulphonates may be obtained from the process by omitting the treatment with a basic metal oxide or hydroxide.  Specified metal oxides and hydroxides which may be used are those of sodium, calcium, barium, zinc, aluminium, lead, cadmium, molybdenum, magnesium and copper.