Patent GB-668268-A (GB)
Title: Process for the pyrolysis of ketenizable organic compounds
IPC: C07C45/88
Filed: 1947-08-08
Abstract: <PICT:0668268/IV (b)/1> Pyrolysis of ketenizable organic compounds such as acetone or acetic acid to produce ketene and other products is effected in the vapour phase at temperatures of the order of 1000 DEG  C. or above in a vessel constructed of a non-catalytic high chrome, nitrogen steel alloy containing 24-27 per cent chromium, 0.12-0.3 per cent nitrogen, up to 0.6 per cent manganese, up to 1 per cent nickel, up to 0.2 per cent carbon, the balance being iron. Silicon up to 1.5 per cent, and small fractions of a per cent of other elements such as sulphur may be present.  Examples of alloys having compositions within these limits are given.  Acetic acid may be fed through vaporizer 2 to preheater 5 where it is heated to 600-800 DEG  C.  A catalytic phosphate compound may be introduced at 6.  The vapours pass through pyrolysis vessel 8 of the high chrome, nitrogen alloy, and ketene is separated in condenser 12. Both preheater and pyrolyzer may be enclosed in a chamber of firebrick having a baffle 14 and partition 15.  Reduced, elevated or atmospheric pressure may be used.  The Specification as open to inspection under Sect. 91 comprises the use of any high chrome, nitrogen steel containing 18-40 per cent Cr, about 0.2-1.5 per cent N, and small amounts of Mn, Ni and C, the balance being iron.  This subject-matter does not appear in the Specification as accepted.ALSO:<PICT:0668268/III/1> Pyrolysis of ketenizable organic compounds is effected in the vapour phase at temperatures of the order of 1000 DEG C or above in a vessel constructed of a non-catalytic high chrome, nitrogen steel alloy containing 24-27 per cent chromium, 0.12-0.3 per cent nitrogen, up to 0.6 per cent manganese, up to 1 per cent nickel, up to 0.2 per cent carbon, the balance being iron.  Silicon up to 1.5 per cent and small fractions of a per cent of other elements such as sulphur may be present. Examples of alloys having compositions within these limits are given. Acetic acid may be fed through vaporizer 2 to preheater 5 where it is heated to 600-800 DEG C.  A catalytic phosphate compound may be introduced at 6.  The vapours pass through pyrolysis vessel 8 of the high chrome, nitrogen alloy, and ketone is separated in condenser 12. Both preheater and pyrolyzer may be enclosed in a chamber of firebrick having a baffle 14 and partition 15.  Reduced, elevated or atmospheric pressure may be used.  The Specification as open to inspection under Sect. 91 comprises the use of any high chrome, nitrogen steel containing 18-40 per cent Cr., about 0.2-1.5 per cent N, and small amounts of Mn, Ni and C, the balance being iron.  This subject-matter does not appear in the Specification as accepted.ALSO:Pyrolysis of ketenizable organic compounds is effected in a vessel constructed of a non-catalytic high chrome, nitrogen steel alloy containing 24-27 per cent chromium, 0.12-0.3 per cent nitrogen, up to 0.6 per cent manganese, up to 1 per cent nickel, up to 0.2 per cent carbon, the balance being iron.  Silicon up to 1.5 per cent and small fractions of a per cent of other elements such as sulphur may be present.  Examples of alloys having compositions within these limits are given.  The Specification as open to inspection under Sect. 91 comprises the use of any high chrome, nitrogen steel containing 18-40 per cent Cr., about 0.2-1.5 per cent N, and small amounts of Mn, Ni and C, the balance being iron.  This subject-matter does not appear in the Specification as accepted.