Patent GB-470715-A (GB)
Title: Improvements in the manufacture of soap
IPC: C11D13/02
Filed: 1936-03-14
Abstract: Unsaponifiable matter is extracted from saponified wool grease, by extraction with cold or warm solvents such as carbon tetrachloride or acetone.  Extraction may be assisted by addition of sodium nitrite, ammonium sulphate or sodium chlorate during saponification.  The extract is freed from soap by dilution with solvent after which the purified product consisting of cholesterol, isocholesterol and other alcohols is recovered.  This is treated with excess of concentrated sulphuric acid at 140 DEG  C., and after (a) repeated washing with water, (b) neutralizing with caustic soda, (c) precipitation with hydrochloric acid, (d) conversion into the calcium salt, filtering, and (e) treating with acid, the resulting sulphonated product may be used as a wetting agent.  The filtrate from (d) after boiling with hydrochloric acid and neutralization with soda forms a product also useful as a wetting-agent.  Sterols are obtained by vacuum distillation of the crude saponified product (b).ALSO:Soap is obtained by saponifying wool grease by heating it with anhydrous caustic alkali, e.g. to about 550 DEG  C. with caustic soda or to 450 DEG  F. with potash, until frothing has subsided, the temperature being gradually raised, while stirring.  The soap may be ground into fine powder or rolled into thin sheets and cut into ribbons.  The soap may be freed from unsaponifiable matter by extraction with cold or warm solvents, e.g. benzine or carbon tetrachloride, or acetone. The extraction is aided by the addition to the soap before cooling of metal salts of low melting point, e.g. sodium nitrite, ammonium sulphate, sodium chlorate. The extract is freed from soap by further dilution and the unsaponifiable matter consisting of polymerized cholesterol and other alcohols is recovered.  This may be treated with excess of concentrated sulphuric acid at 140 DEG  C., and after (a) repeated washing, (b) neutralizing with caustic soda, (c) precipitation with hydrochloric acid, (d) conversion to the calcium salt, filtering, and (e) treating with acid, the resulting precipitated material is used for fat splitting; and the filtrate from (d) after boiling with hydrochloric acid and neutralizing with soda is used as a wetting agent.  Sterols may be obtained by vacuum distillation of the crude neutralized product (b).  The crude unsaponifiable material may also be added to lubricating oils, the mixture heated with an adsorbent and after filtration yielding a lubricating oil of low cold test suitable for high pressure lubrication.  The soaps may be split to form the fatty acids which are separated by distillation into fractions of high and low molecular weight.  The low molecular acids are converted into soap and the high molecular acids used in lubricating grease or in wax compositions.  The crude soap (including unsaponifiable matter) is dissolved in water and treated with copper sulphate to form a bright green copper compound; this includes the unsaponifiable matter and after washing and drying, is dissolved in turpentine or white spirit and pigments added if desired to form a paint. Additional extracted unsaponifiable matter which has drying properties may be added.  The lead, or aluminium soaps, the latter having anti-settling properties in paints, or the brown precipitate obtained with iron salts, may be similarly used.  The calcium and aluminium soaps may be used to improve the properties of lubricating oils, or in bituminous compositions for application to roofing felt.  In examples, (1) crude lime soap is added to spindle oil with stirring and then oleic acid and glycerine are added.  After cooling somewhat a small amount of water is added to form a lubricating grease; (2) equal amounts of the aluminium soap and tough bitumen are melted together at 200 DEG  C., to form a homogeneous high - melting bituminous composition. Specification 396,769 is referred to.