Patent GB-790211-A (GB)
Title: Process for the production of 8-ketotricyclodecene-4
Filed: 1954-06-16
Abstract: 8-Keto tricyclo decene-4 is prepared by subjecting 8-hydroxy tricyclo decene-4 to dehydrogenation at a temperature of at least 200 DEG  C., but preferably not above 370 DEG  C., in the presence of a dehydrogenation catalyst comprising or consisting of a metal of Group 1B and/or a metal of Group 8, or of an oxide of a metal of Groups Ib, IIb and VIa of the Periodic Table; the oxide catalysts may be promoted by means of an oxide of a metal of Group 5.  The dehydrogenation may be effected in the liquid phase, for example at 200-250 DEG  C., or in the gaseous phase suitably at above 300 DEG C.; normal or slightly elevated pressure may be used.  In the gas phase reaction, the metal oxides are the preferred catalysts as the metal catalysts promote dehydration with formation of olefinic hydrocarbons in addition to the desired ketones; a preferred catalyst is zinc-oxide on a nondehydrating carrier such as metal turnings, which may be surface-oxidized, or glass Raschig rings.  The formation of olefines in the gas phase reaction may be reduced by mixing the catalyst with sulphur or a sulphur compound of a metal in which the sulphur is present in the divalent form, for example, zinc or iron sulphide.  Suitable methods for regenerating the catalysts are described.  In examples (1)-(2) the hydroxy-tricyclo decene is converted to the ketone by liquid phase dehydrogenation at temperatures ranging from 220-236 DEG  C. using (a) finely divided copper catalyst; (b) a reduced copper-magnesia-kieselguhr catalyst, which results in some formation of dicyclo pentadiene; or (c) a copper oxide-chromium oxide catalyst.  In Example (3) the hydroxy compound is passed in vapour form in a stream of nitrogen through a glass tube heated to 350-370 DEG  C. and containing a zinc-oxide-bismuth oxide catalyst, if desired admixed with zinc sulphide, supported on rusty iron turnings, glass rings or iron sulphide, and the resulting keto-tricyclo decene is condensed out from the hydrogen also formed.  Nickel-magnesia on kieselguhr and chromium oxide-alumina are also specified as catalysts.ALSO:Catalysts for the dehydrogenation of 8-hydroxy tricyclodecene - 4 to 8 - ketotricyclodecene-4 (see Group IV (b)) comprise or consist of a metal of Group 1B and/or a metal of Group 8, or of an oxide of a metal of Groups 1B, 2B and 6A of the Periodic Table. The metal oxide catalysts may be promoted by an oxide of a metal of Group 5.  The catalysts may be used in liquid or vapour phase dehydrogenation of the alcohol.  The metal oxides are preferred for the gas-phase reaction as the metal catalysts then promote greater dehydration of the alcohol to olefines.  Hydrocarbon formation in the gasphase reaction may be reduced by using the catalyst in admixture with sulphur or a sulphur compound of a metal in which the sulphur is in bivalent form, e.g. iron or zinc sulphide.  When carrier materials are employed, it is preferred to use metal turnings, for example, of copper or iron, which may be surface-oxidized, or glass Raschig rings; kieselguhr, pumice, Stuttgart mass and other materials containing active silicates or silicic acid are less desirable on account of their dehydrating properties.  Catalysts used in examples are finely divided reduced copper, a copper-magnesia-kieselguhr catalyst, a copper oxide-chromium oxide catalyst and a mixture of zinc oxide and bismuth oxide, with or without zinc sulphide, pasted on rusty iron turnings or supported on glass rings or iron sulphide. Other catalysts mentioned are nickel-magnesia on kieselguhr and dehydrogenation catalysts based on chromium oxide-alumina.  The metal catalysts on deactivation may be regenerated by treatment with hydrogen in the presence of 8-hydroxytricyclo - decene - 4 or - decane - 4 at preferably 100-130 DEG  C.  The sulphur-containing oxide catalysts are regenerated by heating in the absence of oxygen, for example by heating at 300-350 DEG  C. in a stream of nitrogen or nitrogen and hydrogen; the other oxide catalysts are regenerated by ignition, if desired after extraction with a light hydrocarbon.