GB665976A - Controlled catalytic vapor phase process - Google Patents

Abstract

In the catalystic gaseous phase oxida<PICT:0665976/IV (b)/1> tion of organic compounds, e.g. the oxidation of naphthalene, o-xylene or o-toluic acid to phthalic anhydride, of methyl pentadiene, benzene or butene- 2 to maleic acid and of propylene to propylene oxide and acrolein, with air or other oxidizing gas at 240-600 DEG C., the finely - divided solid catalyst is allowed to fall freely as a shower through a reaction zone 1 to make contact for a short period, preferably less than one second, with the upwardly flowing reactant gases which enter at 7 and leave at 8, the solid collecting at 2 being purged of vapour by a stripping gas, e.g. steam, air or mixtures thereof, entering at 10, and then recycled to the top of the reactor through line 5 with the aid of a pick-up gas entering at 4. A separator 6 serves to disengage solid from gas at the top of the reactor. To minimize absorption of reactant vapours by the incoming catalyst, steam or inert gas may be admitted at 9. Heat exchange surfaces may be included in the reactor and in line 5.ALSO:<PICT:0665976/III/1> In reacting gases or vapours in the presence of a finely-divided catalytic solid, the solid is allowed to fall freely as a shower through a reacting zone 1 to make contact for a short period, preferably less than one second, with the upwardly flowing reactant gases which enter at 7 and leave at 8, the solid collecting at 2 being purged of vapour by a stripping gas, e.g. steam, air or mixtures thereof, entering at 10, and then recycled to the top of the reactor through line 5 with the aid of a pick-up gas entering at 4. A separater 6 serves to disengage solid from gas at the top of the reactor. To minimize absorption of reactant vapours by the incoming catalyst, steam or inert gas may be admitted at 9. Heat-exchange surfaces may be included in the reactor and in line 5. The method is applicable to the oxidation of organic compounds with air or other oxidizing gas at 240-600 DEG C, e.g. the oxidation of naphthalene, o-xylene or o-toluic acid to phthalic anhydride, of methyl pentadiene, benzene or butene 2 to maleic acid and of propylene to propylene oxide and acrolein employing as catalysts vanadium oxide, vanadium oxide-molybdenum oxide, vanadium oxide on silica gel or cuprous oxide on silica gel in the form of 20-60 mesh microspheres.