Patent GB-589546-A (GB)
Title: Improved process for the dehydrogenation of hydrocarbons
IPC: C07C5/333
Filed: 1943-03-25
Abstract: The dehydrogenation of paraffins and olefins to olefins or diolefines is effected by pre-heating the hydrocarbon to below dehydrogenation temperature, and mixing in a reaction zone with superheated steam whereby the hydrocarbon is heated to dehydrogenation temperature, said reaction zone containing a catalyst comprising a mixture of magnesium oxide and ferric oxide, and small amounts of other metal oxides acting as promoters and stabilizers.  The dehydrogenation of butene to butadiene may be effected by heating to about 1100 DEG F., mixing with about 7-12 molar proportions of steam superheated to 1800-2000 DEG F. to give a reaction temperature of 1150-1250 DEG F., the mixture remaining in the reactor for a very short time, for example 0.01-0.1 sec.  A pressure of 5-40 p.s.i absolute is maintained.  The catalyst contains 50-95 per cent.  MgO, 3-49 Fe2O3, 0.5-10 each CuO and K2O, K2O, which acts as a promoter may be replaced by CaO or SrO, and CuO, acting as a stabilizer, by oxides of Ag, Zr, Cr, Mn, Co, Ni, Th, Ce, Pb, Bi or Al.  A preferred mixture is MgO, 78, Fe2O3, 20, CuO, 5, and K2O, 2.5 parts by weight.  The reaction products may be quenched and washed with water, compressed and cooled to liquefy and to separate from gases such as hydrogen and methane, and then stabilized to remove C1 to C3 gases as overhead, and fractionated to separate a C4 cut from C5 and heavier. The C4 cut is extracted with a butadiene solvent such as acetone, methylamine, ammonia, aqeous cuprous chloride or ammoniacal cuprous acetate, the butene being recycled. Specification 565,241 is referred to.  The Specification as open to inspection under Sect. 91 comprises also effecting the dehydrogenation in the absence of a catalyst or with such catalysts as chromic or molybdenum oxide or alumina, and with other gaseous diluents such as nitrogen, hydrogen or carbon dioxide in place of steam.  This subject-matter does not appear in the Specification as accepted.ALSO:The dehydrogenation of paraffins and olefins to olefins or diolefins is effected by preheating the hydrocarbon to below dehydrogenation temperature and mixing in a reaction zone with superheated steam, whereby the hydrocarbon is heated to dehydrogenation temperature, said reaction zone containing a catalyst comprising a mixture of magnesium oxide and ferric oxide, and small amounts of other metal oxides acting as promoters and stabilizers.  The dehydrogenation of butene to butadiene may be effected by heating to about 1100 DEG  F., mixing with about 7-12 molar proportions of steam superheated to 1800-2000 DEG  F. to give a reaction temperature of 1150-1250 DEG  F., the mixture remaining in the reactor for a very short time, for example 0.01-0.1 sec.  A pressure of 5-40 p.s.i. absolute is maintained.  The catalyst contains 50-95 per cent MgO, 3-49 Fe2O3, 0.5-10 each CuO and K2O. K2O, which acts as a promoter, may be replaced by CaO or SrO, and CuO, acting as a stabilizer, by oxides of Ag, Zr, Cr, Mn, Co, Ni, Th, Ce, Pb, Bi or Al.  A preferred mixture is MgO, 78, Fe2O3, 20, CuO, 5, and K2O, 2.5 parts by weight.  The reaction products may be quenched and washed with water, compressed and cooled to liquefy and to separate from gases such as hydrogen and methane, and then stabilized to remove C1 to C3 gases as overhead, and fractionated to separate a C4 cut from C5 and heavier. The C4 cut is extracted with a butadiene solvent such as acetone, methylamine, ammonia, aqueous cuprous chloride or ammoniacal cuprous acetate, the butene being recycled. Specification 565,241, [Group III], is referred to.  The Specification as open to inspection under Sect. 91 comprises also effecting the dehydrogenation in the absence of a catalyst or with such catalysts as chromic or molybdenum oxide on alumina, and with other gaseous diluents such as nitrogen, hydrogen or carbon dioxide in place of steam.  This subject-matter does not appear in the Specification as accepted.