GB1201379A - Process for the electrolytic production of olefin oxides from olefins - Google Patents

Abstract

1,201,379. Electrolytically producing olefin oxides. FARBENFABRIKEN BAYER A.G. 4 Oct., 1967 [14 Oct., 1966], No. 45199/67. Heading C2C. [Also in Division C7] Olefin oxides are electrolytically produced from olefins, e.g. ethylene, propylene, butylene, or halogenated mono-olefins, e.g. allyl chloride, using a diaphragm cell 1 with an aqueous electrolyte containing an alkali metal halide, e.g. NaCl and/or KCl, wherein a halogen component of the anolyte or a hydrolysis product thereof is reacted in a reactor 5 outside the cell with an olefin or a halogenated mono-olefin, e.g. introduced with an inert paraffin gas through a gas distributer 9, to form the corresponding halohydrin, which is subsequently reacted with the alkaline catholyte to form the olefin oxide by dehydrohalogenation. Preferably, circulation of the anolyte is maintained between the anode compartment and the reactor by pipes 6, 7 and the upward flow of gas in the reactor. A component stream from the anolyte circuit may be delivered through the diaphragm 4 to the catholyte compartment (Fig. 1) or reacted with the alkaline catholyte outside the cell in dehydrohalogenation reactor 17 as shown, the electrolyte being returned to the cell via pipe 12 after separation of the olefin oxide formed through pipe 15, preferably facilitated by steam and/or vacuum. Similarly, circulation of the catholyte may be maintained inside or outside the cell, e.g by pipes 19 and the upward flow of hydrogen in the cathode compartment. The component anolyte streams from a plurality of cells may be reacted together with the olefin or halogenated mono-olefin in one reactor, and the component catholyte streams thereof then reacted in one dehydrohalogenation reactor. The anode 2 may be of graphite, or Ti coated with a Pt group metal, the uncoated parts being protected with an oxidic layer. The cathode 3 is preferably a wire gauze of iron or steel. The diaphragm 4 may be of asbestos, polyfluorohydrocarbons, polyolefins, e.g. polyethylene, -propylene, -butylene, polystyrenes, polyacrylonitrile, PVC or copolymers of vinyl and vinylidene chloride, in the form of porous plates or woven fabrics; porous Ti may also be used. The pressure in the anode compartment is preferably higher than that in the cathode compartment.