Continuous process for the preparation of fatty acids, in particular of C8-C18-fatty acids by catalytic oxidation of n-alkanes

摘要

The present invention describes a continuous process for the preparation of fatty acids, in particular of C8-C18-fatty acids, by selective oxidation of n-alkanes using a gas containing the oxygen in the presence of catalysts in a gas-liquid system, the liquid n-alkanes being brought into contact with an added catalyst and optionally an initiating agent in countercurrent in an absorption column using a gas which contains oxygen in a 2-8-fold excess in relation to the liquid phase. The process is carried out at a temperature of over 160 DEG C under normal pressure or under a pressure increased up to 2 MPa and under a loading of the column with the gas of 800-6000 m<3>/m<2>h and with the liquid of 2.5-20 m<3>/m<2>h. The acids formed can be withdrawn from the upper part of the column together with the stream of waste gases if the loading of the column with the liquid is up to 2.5 m<3>/m<2>h and with the gas 6000-8000 m<3>/m<2>h. The time of initiation of the reaction can be cut by using an initiating system consisting of 0.1-0.5 % by weight of potassium permanganate and 0.05-0.1 % by weight of a phase transfer catalyst, in proportion to the amount of n-alkanes.