Patent GB-497757-A (GB)
Title: Manufacture of aliphatic aldehydes
IPC: C07C45/75
Filed: 1937-06-26
Abstract: Higher unsaturated aliphatic aldehydes are produced by continuously passing a mixture of two different aldehydes in the vapour phase over a dehydrating catalyst and continuously condensing the product.  The product may be hydrogenated to produce a saturated aldehyde, and the hydrogenation may be effected in the vapour phase.  In the apparatus shown, Fig. 1, the reagents are supplied from tanks 11, 16 to a vaporizer 17 and thence to a catalyst <PICT:0497757/III/1> <PICT:0497757/III/2> <PICT:0497757/III/3> chamber 19 and hydrogenation catalyst chamber 28; the catalyst chambers are provided with heating-coils 21, 29 and thermometer wells 25, 35.  Hydrogen is admitted at 32.  In Fig. 2, the p  reagents from tanks 52, 62 are separately vaporized and mixed at 58 and led through a heat-exchanger 71 to the catalyst chamber 72 the outer space 70 of which acts a heat-exchanger.  The product condensed at 77 from which it passes to a tank 79 and thence to a hydrogenation chamber 82 connected to a condenser 89.  For the initial reaction the catalyst may be silica or alumina gel which may be impregnated with sodium, magnesium or cadmium acetate, thoria, molybdenum oxide or cobalt or magnesia carrying 2-10 per cent of metallic cobalt; or magnesium formate, vanadium pentoxide or tungsten oxide on a gel carrier or granulated magnesia may be used.  For hydrogenation the catalyst may be nickel which has been made by removing by means of an alkaline or other solvent the additional ingredients from an alloy of nickel with aluminium, silicon or the like.  Examples describe the production from acetaldehyde and formaldehyde of acrolein and its hydrogenation to propionic aldehyde.  The production of ethyl acrolein and methyl acrolein from formaldehyde and butyl and propionic aldehydes respectively is mentioned.  The apparatus may be made of a steel containing 16-23 per cent chromium, 7-20 per cent nickel, preferably 0,1 per cent carbon or less, and may contain small amounts of copper, silicon, molybdenum, and tungsten.  The remainder is iron.ALSO:<PICT:0497757/IV/1> <PICT:0497757/IV/2> Higher unsaturated aliphatic aldehydes are produced by continuously passing a mixture of two different aldehydes in the vapour phase over a dehydrating catalyst and continuously condensing the product.  The product may be hydrogenated to produce a saturated aldehyde, and the hydrogenation may be effected in the vapour phase.  In the apparatus shown, Fig. 1, the reagents are supplied from tanks 11, 16 to a vaporizer 17 and thence to a catalyst chamber 19 and hydrogenation catalyst chamber 28; the catalyst chambers are provided with heating-coils 21, 29 and thermometer wells 25, 35.  Hydrogen is admitted at 32.  In Fig. 2, the reagents from tanks 52, 62 are separately vaporized and mixed at 58 and led through a heat-exchanger 71 to the catalyst chamber 72, the outer space 70 of which acts as a heat-exchanger.  The product is condensed at 77 from which it passes to a tank 79 and thence to a hydrogenation chamber 82 connected to a condenser 89.  For the initial reaction the catalyst may be silica or alumina gel which may be impregnated with sodium, magnesium or cadmium acetate, thoria, molybdenum oxide or cobalt; or magnesia carrying 2-10 per cent of metallic cobalt; or magnesium formate, vanadium pentoxide or tungstic oxide on a gel carrier or granulated magnesia may be used.  For hydrogenation the catalyst may be nickel which has been made by removing by means of an alkaline or other solvent the additional ingredients from an alloy of nickel with aluminium, silicon or the like.  Examples describe the production from acetaldehyde and formaldehyde of acrolein and its hydrogenation to propionic aldehyde. The production of a -ethyl acrolein and a -methyl acrolein from formaldehyde and butyl and propionic aldehydes respectively is mentioned.  The apparatus may be made of a steel containing 16-23 per cent chromium, 7-20 per cent nickel, preferably 0,1 per cent carbon or less, and may contain small amounts of copper, silicon, molybdenum, and tungsten.  The remainder is iron.ALSO:An Alloy for the construction of catalytic apparatus contains 10-23 per cent chromium, 7-20 per cent nickel, preferably 0,1 per cent carbon or less, and may contain small quantities of copper, silicon, molybdenum, and tungsten.  The remainder is iron.