Catalytic oxidation of acetylene in air

Catalytic Oxidation of Acetylene in Air for Oxygen Manufacture J. Henry Rushton and K. A. Krieger The Poisoning of Metallic Catalysts E. B. Maxted... 

Henry Rushton, Catalytic Oxidation of Acetylene in Air for Oxygen Manu-factuie.107... 

Crude MWCNTs and SWCNTs were produced by catalytic decomposition of acetylene on Co-Fe/Al(OH)3 catalysts. The CNTs contained used catalysts and other by-products. The catalysts and support contents of the CNTs samples are shown in Table 7.3. Crude MWCNTs contain Co, Fe, and alumina. Purified MWCNTs were synthesized from crude MWCNTs by dissolution of the catalyst support in concentrated NaOH, dissolution of the metal catalyst in concentrated HCl, drying at 120°C in an air oven and additional drying at 500°C under vacuum. Crude SWCNTs contain Co and MgO. Purified SWCNTs were synthesized from crude SWCNTs by dissolution of the catalyst support in concentrated HCl, purification by air oxidation at 300°C and then drying at 120°C in an air oven. 

In the 1960s, like almost all acetylene technology, the HCN/C2H2 route to acrylonitrile gave way to ammoxidation of, propylene. Thar word, ammoxidation, looks suspiciously like the contraction of two more familiar terms, ammonia and oxidation, and it is. When Standard of Ohio (Sohio) was still a company they developed a one-step vapor phase catalytic reaction of propylene with ammonia and air to give acrylonitrile. 

The direct catalytic, oxidation method of ethylene is described in Ref 17, pp 77—87 Explosibility. Liquid ethylene oxide is stable to detonating agents, but the vapor will undergo explosive decomposition. Pure ethylene oxide vapor will decompose partially however, a slight dilution with air or a small increase in initial pressure provides an ideal condition for complete decomposition. Copper or other acetylide-forming metals such as silver, magnesium, and alloys of such metals should not be used to handle or store ethylene oxide because of the danger of the possible presence of acetylene. Acetylides detonate readily and will initiate explosive decomposition of ethylene oxide vapor. In the presence of certain catalysts, liquid ethylene oxide forms a poly-condensate. 

Mixtures of acetaldehyde and acetic acid may be obtained121 by passing acetylene (2 to 3 volumes) and air (10 volumes) mixed with a large excess of steam over the zinc, copper, nickel, or cadmium salts of vanadic, molybdic, or chromic acids deposited upon a suitable base, such as pumice, at temperatures ranging from 300° to 400° C. For example, yields of 75 to 80 per cent acetaldehyde along with 5 per cent acetic acid have been obtained by using basic zinc vanadate at 380° C. The aldehyde is separated by fractional condensation in a column and the condensed fraction which is poor in aldehyde is utilized to furnish steam for the catalytic treatment of more acetylene. The fractions rich in acetaldehyde serve for the direct recovery of the aldehyde or may be oxidized immediately to acetic acid by passage over a suitable catalyst. In this way, the process may also be applied directly to the preparation of acetic acid from acetylene. 

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