| 摘要 |
Oleum is produced by burning, preferably at 850-1150 DEG C., ammonium sulphate-containing residues of methyl methacrylate production, to give a gas containing SO2, oxidizing the SO2 to SO3 and absorbing the SO3 in conc. H2SO4/t to form oleum, which when diluted to 6% may be recycled to prepare more methyl methacrylate. Preferably, the residues are sprayed with air and a hydrocarbon gas into a furnace at 950-1050 DEG C.; the resulting gas containing O2, SO2, CO2 and N2 is cooled to less than 40 DEG C., scrubbed, heated to 300-500 DEG C. and passed over a catalyst bed preferably vanadium-containing at 400-600 DEG C. with added oxygen in amount 100-200% molar excess. The gas is cooled to less than 300 DEG C. and the SO3 absorbed by passage over the surface of a stream of sulphuric acid or through a bubble-plate or packed tower in countercurrent to H2SO4, to form 20% oleum. |
