GB801880A - Process for preparing methyl ethyl ketone from secondary butanol - Google Patents

Abstract

Methyl ethyl ketone is prepared by dehydrogenation of secondary butanol by a continuous process comprising vaporizing and heating the alcohol to 800-900 DEG F. in a first heating zone, passing the heated vapour to a first reaction chamber packed with a metallic oxide dehydrogenation catalyst, the temperature within the chamber being maintained within the range 650 DEG to 900 DEG F. solely by the incoming vapours, passing the effluent vapours from the first reaction chamber through at least one further combination of heating zone and reaction chamber packed with the catalyst, under the same conditions as in the first combination of heating zone and reaction chamber and passing the effluent vapours from the last reaction chamber through a condensing zone and separat <PICT:0801880/IV (b)/1> ing therefrom methyl ethyl ketone. As shown, the alcohol is preheated in a heat-exchanger 43 and passed via line 1 through tube 3 in a furnace 2 where it is heated in the convection section 44 and also, if desired, in a radiant section 45, to a temperature of 800-900 DEG F. and the vapours then pass directly via line 4 into reactor 5 containing a fixed catalyst bed 6. The partially converted effluent vapours from reactor 5 are passed via line 7 to a second heating coil 8 wherein the temperature of the vapours is again raised to 800-900 DEG F. and the vapours then flow via line 9 into second reactor 10 and the same procedure is repeated via line 11, coil 12 and third reactor 14. Additional heating and reaction cycles may be provided. The effluent from the final reactor 14 is passed via line 15 and exchanger 43 to a condenser 16 and thence to a settler from which methyl ethyl ketone is separated from hydrogen. If desired, part of the alcohol may by-pass the furnace via line 19. The alcohol feed-stock used should preferably contain at least 90 wt. per cent of alcohol and less than 0.5 wt. per cent of water. The catalyst, which is preferably a Group II metal oxide, may be zinc oxide, magnesium oxide, copper oxide, beryllium oxide or chromium oxide. It may be promoted or stabilized by 1-15 per cent of an oxide of a Group III, IV or V metal such as a bismuth, antimony, zirconium, thorium, cerium or vanadium oxide, or sodium carbonate and may be supported on a carrier such as brass turnings, metal chips, aluminium, porcelain or calcined coke. Elevated pressures may be used. An example is given using as catalyst 92-96 wt. per cent of ZnO and 4-8 wt. per cent of Na2CO3 on calcined coke.