Patent GB-321494-A (GB)
Title: Improvements in and relating to the manufacture of liquid oxidation products from hydrocarbon materials
IPC: C07C27/10
Filed: 1928-09-07
Abstract: 321,494. Arnold, C., (Standard Oil Development Co.). Sept. 7, 1928. Formaldehyde; acetaldehyde; formic and acetic acids; acetone; methyl, ethyl, propyl, and butyl alcohols; propyl acetate.-Liquid oxidation products such as alcohols, aldehydes and acids are produced by treating gaseous or low-boiling hydrocarbon vapour with a gas containing oxygen under pressure exceeding 500 lbs. at an elevated temperature. The hydrocarbon may be a single compound or a mixture and is supplied under pressure from a container 1 to a manifold 2 and thence to coils a - - d in a reaction chamber 4 to preheat the hydrocarbon by heat exchange. The reaction chamber 4 is adapted to withstand 600‹ C., or higher, at 200 atmospheres' and mav contain catalytic material. Hydrocarbon is also passed through a heat exchanger F, and part may also be by-passed through a tube E. The hydrocarbon passing through all these branches is led to a manifold 5, thence through a heater 6 and pipe 7 to the reaction chamber 4. Air or oxygen is supplied from a compressor 8 to the pipe 7, and may also be supplied to the reaction chamber through a pipe 9 having branches a<1>, b<1>, c'. The reaction products are cooled in the heat-exchanger F and a cooler 10 and pass through a reducing valve 11 to the middle of a rectifying column 12, which may have a cooling-coil 13 at the top, and a heating coil 14 at the bottom. Nitrogen and other permanent gases escape at the top of the column and are scrubbed in a tower 16 with a suitable solvent to recover any normally liquid products, and gaseous products such as formaldehyde which have escaped condensation in the column 12. The liquid from the bottom of the column 12 is passed to a liquid scrubbing column 24, the arrangement shown being for a solvent of higher density than the hydrocarbon, which solvent is therefore admitted at the top. The solvent and oxidation products pass out by a pipe 27 to a tank 20 or to a storage tank by a pipe 28. The solvent used in the towers 16 and 24 may be the same and a pump 29 and pipe 30 are shown for the circulation, but different solvents may be used. Unoxidized hydrocarbon is drawn from the top of the column 24 by a pump 33 by pipe 34 to a tower 35, an alkaline solution such as caustic soda being circulated by a pump 37 and pipe 38 so as to remove carbon dioxide from the hydrocarbon. The purified hydrocarbon is then withdrawn by a pump 42 and returned by a pipe 43 to the container 1. The process is effected at pressures above 500 lbs. and preferably 1500- 3500 lbs., the reaction chamber being at 350- 600‹ C. Particulars are given of suitable temperatures for the oxidation of a mixture of methane and ethane, using the following catalysts :-vanadium pentoxide powder, hard glass tube, copper wire coated with fused borax, copper wire coated with fused sodium tungstate, silver wire, platinum foil, brass tube, nickel wire, nickel reduced on pumice, iron wire, copper wire plated with cobalt, copper wire coated with fused borax and sprinkled with iron powder, lump calcium, manganese pieces, steel tube, clay, chromium nickel alloy wire, and aluminium wire. Preferably the process is started by heating up the apparatus while supplying hydrocarbon alone, the oxygen being added gradually. One atom of oxygen per molecule of hydrocarbon is the maximum, but proportions as low as 5 per cent or less may be used. The column 12 may be at 50-60 atmospheres, the temperature at the top being preferably below atmospheric and at the base from 100 to 200‹ C., but if methane is to be condensed a very low temperature must be used in the coil 13. The solvent employed in the towers 16 and 24 is preferably heavier than the hydrocarbon and contains preferably a hydroxyl group, such as water, glycerine, ethylene glycol or methanol or mixtures of such substances. In the examples (1) purified methane with 6.8 per cent of oxygen is passed at 2000 lbs. pressure over nickel wire at 520-585‹ C., yielding mainly methanol; (2) a mixture of methane with 20 per cent of ethane and with 5.6 per cent of oxygen is passed at 2000 lbs. pressure over nickel wire at 395‹ C., the product being mainly methanol with some ethanol; (3) propane with 5.3 per cent of oxygen is passed at 500 lbs. pressure over nickel wire at 380‹ C., yielding ethanol, acetone, formic acid, methanol, propanol and acetaldehyde: (4) butane with 4.9 per cent of oxygen is passed at 2400 lbs. pressure over nickel wire at 430‹ C. yielding propanol, propyl acetate, acetic acid, ethanol, butanol, and methanol. In each case the velocity of the gas stream in relation to the catalyst area is defined. The process may be applied to the treatment of pentane, and mixtures such as natural gas, coal gas, refinery gas, and gasolines.