GB391444A - Improvements in or relating to the manufacture of acetaldehyde - Google Patents

Abstract

<PICT:0391444/IV/1> <PICT:0391444/IV/2> In the production of acetaldehyde by the vapour phase oxidation of ethyl alcohol, all or part of the oxygen and/or the alcohol is introduced into the reaction zone at a number of points spaced along the reaction zone in or parallel to the line of flow of the gases through the zone. For this purpose perforated members or pipes may be arranged in or around a bed of catalyst, or the catalyst bed may be surrounded by a perforated shell. Preferably the oxygen or air is added through the perforated members, the alcohol, which may contain some oxygen (e.g. 10-20 per cent) being passed through the catalyst bed. The total quantity of oxygen used may be the theoretical quantity or more or less, and diluents such as nitrogen, carbon dioxide or steam may be present with either of the reactants. The catalyst may be silver, copper, or silver or copper oxide at 250-500 DEG C. The temperature of the catalyst may be controlled by means of hollow heat-exchanging elements within the reaction zone and supplied with water or other cooling fluid, and such cooling fluid may be caused to move as a travelling film as described in Specification 390,186. If desired the reactant introduced at various points may be at lower temperature than the reaction stream. In the apparatus shown, a catalyst bed 2 is arranged in a reaction vessel 1 having cooling members 3 formed of concentric tubes, the outer tubes being closed at the top and connected at the bottom to a water-box 6, while the inner tubes are open at the top and connected with a steam-box 8, water being admitted at 7 and steam escaping at 9. Reactants are supplied at 13 through a chamber 12 and perforated pipes 10, and at 15 through a perforated plate 19 direct to the catalyst bed, the reaction products being withdrawn at 17. There may be several inlets 15 disposed around the vessel 1. In a modification Fig. 2, the reactants are supplied together through the inlet 13, part of the mixture passing direct through the catalyst bed by way of the perforated plate 19, and part through the perforated pipes 10. Specification 390,504 is referred to.ALSO:<PICT:0391444/III/1> <PICT:0391444/III/2> In the production of acetaldehyde by the vapour phase oxidation of ethyl alcohol, all or part of the oxygen and/or the alcohol is introduced into the reaction zone at a number of points spaced along the reaction zone in or parallel to the line of flow of the gases through the zone. For this purpose perforated members or pipes may be arranged in or around a bed of catalyst, or the catalyst bed may be surrounded by a perforated shell. Preferably the oxygen or air is added through the perforated members, the alcohol which may contain some oxygen (e.g. 10-20 per cent) being passed through the catalyst bed. The total quantity of oxygen used may be the theoretical quantity or more or less, and diluents such as nitrogen, carbon dioxide or steam may be present with either of the reactants. The catalyst may be silver, copper or silver or copper oxide at 250-500 DEG C. The temperature of the catalyst may be controlled by means of hollow heat-exchanging elements within the reaction zone and supplied with water or other cooling fluid, and such cooling fluid may be caused to move as a travelling film as described in Specification 390,186. If desired the reactant introduced at various points may be at lower temperature than the reaction stream. In the apparatus shown, a catalyst bed 2 is arranged in a reaction vessel 1 having cooling members 3 formed of concentric tubes, the outer tubes being closed at the top and connected at the bottom to a water-box 6, while the inner tubes are open at the top and connected with a steam-box 8, water being admitted at 7 and steam escaping at 9. Reactants are supplied at 13 through a chamber 12 and perforated pipes 10, and at 15 through a perforated plate 19 direct to the catalyst bed, the reaction products being withdrawn at 17. There may be several inlets 15 disposed around the vessel 1. In a modification, Fig. 2, the reactants are supplied together through the inlet 13, part of the mixture passing direct through the catalyst bed by way of the perforated plate 19, and part through the perforated pipes 10. Specification 390,504 is referred to.