GB696050A - Improved manufacture of odourless soaps from low grade oils - Google Patents

Abstract

Odourless soap of high consistency is made continuously from low-grade animal or vegetable oils containing or consisting of unsaturated oils or fats by treating the fatty acids thereof with molten alkali at about 300 DEG C in the absence of water and at substantially atmospheric pressure. The unsaturated components of these oils and fats, which give rise to bad odours and form soft soaps, are converted by the reaction, known as the Varrentrapp reaction, into saturated compounds of two or more carbon atoms less with liberation of hydrogen. The soaps formed are not only harder but are also deodorized. The fats and oils are used in the form of their fatty acids obtained by splitting, the glycerine obtained as a by-product being separated from the fatty acids before the soap-making reaction. In an example, the fatty acids at a temperature slightly above melting point and the molten alkali are passed together duly dosified to a saponifier where they react at about 300 DEG C. The soap leaves the saponifier continuously and the hydrogen passes through a condenser and water seal, which latter maintains a slight uniform pressure in the system to prevent entrance of air. An even temperature is maintained with the help of a small fuel oil burner.