 Old catalyst (1950) AlCl 3 +HCl AlCl 3 corrosivity and problems associated with safe handling and disposal For 1 tonne of EB, use of 2-4 kg catalyst, 1kg of HCl, 5 kg of caustic solution, production of salts  Zeolite catalysts - 1980 Mobil Badger vapour phase process MFI (ZSM5) 370-420°C, 7-27 bar, B/C 2 = 5-20, WHSV 300-400 h -1, recycling of DEB, yield > 99.5%, life time : 1 year - 1995 EB Max liquid phase process MWW (MCM22) 200°C, B/C 2 = 3.5, Yield > 99.9%, life time > 3 years, more energy efficient
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