Patent GB-657598-A (GB)
Title: Improvements in or relating to the production of wetting and detergent materials
Filed: 1946-07-19
Abstract: Surface-active agents are prepared by sulphation of a shale oil fraction boiling within the range 150-350 DEG  C. and being substantially free from nitrogen bases and phenolic bodies, by adding thereto 2.8-18 volumes of sulphuric acid of at least 90 per cent by weight concentration per 100 volumes of feed under conditions such that the temperature does not exceed 20 DEG  C., separating the reaction mixture into a lower acid layer and an upper oil layer, treating this oil layer with an excess of an aqueous alkali-metal carbonate solution and recovering an aqueous solution of the surface-active agents so obtained.  Generally, the sulphuric acid is added to the shale oil fraction over 1-2 hours at such a rate that the temperature does not rise above 20 DEG  C. and the acid layer is then separated from the oil layer by gravity or centrifuging.  In a typical example: a distillate from crude Scottish shale oil is agitated with sulphuric acid and then with caustic soda solution, distilled and a fraction collected having a boiling range of 215-300 DEG  C., the preliminary treatment having reduced the nitrogen content to 0.05 per cent, the sulphur content to 0.16 per cent and removed the phenolic bodies substantially entirely.  The distillate is sulphated, the product allowed to settle and the resulting upper oil layer run into aqueous soda ash with stirring.  The resulting emulsion is heated under reflux and then aqueous isopropyl alcohol added to break the emulsion.  The mixture is settled and the alcoholic layer is separated from an upper oil layer, then stirred with isopropyl alcohol and the mixture allowed to settle; a top layer of oil and bottom layer of aqueous inorganic salts are separated from the middle layer of alcoholic detergent solution.  This solution is given a washing with a petroleum distillate and then subjected to alcohol recovery leaving an aqueous solution useful, e.g., in washing dishes, and which froths with air.  Other examples employ as starting material a wax-free shale oil distillate of boiling range between 180 DEG  and 350 DEG  C. which is similarly refined by means of sulphuric acid and caustic soda as above.  In breaking the emulsion formed in the neutralization step, there may be used other alcohols in place of isopropyl alcohol, e.g. methyl alcohol.  The oil recovered following the neutralization may be subjected to various refining treatments and then employed in another sulphation. Specification 449,169 is referred to.  The Provisional Specification describes the production of surface-active agents by a process comprising adding concentrated sulphuric acid to a wax-free fraction obtained by distillation from shale oil and boiling within the range 150-350 DEG  C. under conditions such that the temperature does not exceed 20 DEG  C., separating the reaction mixture into a lower acid sludge layer and an upper oily layer, treating the latter with an excess of an aqueous alkali carbonate solution and recovering the surface-active agent. Specifications 343,872 and 360,602 also are referred to.ALSO:Wetting and detergent solutions useful, for example, in washing dishes and capable of foaming with air are obtained by sulphation of a shale oil fraction boiling within the range 150 DEG -350 DEG  C. and being substantially free from nitrogen bases and phenolic bodies by adding thereto 2.8-18 volumes of at least 90 per cent sulphuric acid per 100 volumes of feed at a temperature not exceeding 20 DEG  C., separating an oil layer from a lower acid layer, treating the oil layer with an excess of aqueous alkali metal carbonate solution and recovering an aqueous solution of the surface active agents thus obtained (see Group IV (b)).  The solutions described contain about 10 to 15 per cent of sodium alkyl sulphate and lesser amounts of sodium sulphate and sodium carbonate.