| 摘要 |
Exothermic dealkylation.. G4-. Pref. of toluene, takes place in a first reaction zone, pref. at 600-800 degrees C (650-750 degrees C) at 34-45 kg/sq. cm., in the absence or presence of an H2-containing gas, using H2:alkyl aromatic mole ratios of 0.5:1 to 5:1. In a second reaction zone, in heat-exchange with the first, the alkane/s are catalytically cracked in the presence of steam, pref. at 600-800 degrees C (650-700 degrees C) at 30-45 kg/sq. cm., pref. using alkane:steam mole ratios of 2:1 to 6:1 to give an H2-containing gas which is directly fed to the first reaction zone. Pref. cracking catalysts contain 20-35 weight % Ni on a refractory support or 3-15 weight % Re on Al oxide, and also 0.1-10 weight % alkali metal. One cylindrical reactor is pref. used, containing at least one tube. Dealkylation takes place outside the tube, and cracking of the alkane/s inside the tube. Heat released in the exothermic dealkylation process is transferred by the tube wall to the endothermic cracking process. |
