Patent GB-798838-A (GB)
Title: Improvements in or relating to production of higher ketones
IPC: B01J23/40
Filed: 1955-05-20
Abstract: Ketones are prepared by contacting 2,3-epoxy butane or a saturated epoxide whose molecule contains 5-16 carbon atoms and has its oxygen atom joined to at least one secondary carbon atom, at an isomerization temperature of about 200 DEG  to 500 DEG  C. with a catalyst containing a metal from Group Ib or VIII of the Periodic Table supported on an activated carbon base.  The C6 to C15 epoxides preferably have the general formula: <FORM:0798838/IV (b)/1> wherein R1 is a C1-4 alkyl group and R2 is hydrogen or a C1-4 alkyl group or R1 and R2 together form a single polymethylene bridge containing 2-4 carbon atoms, R3 and R4 are hydrogen atoms or C1-4 alkyl groups and n is an integer from 0 to 3.  Thus, the epoxide nucleus may be that of ethylene or propylene oxide or preferably of tetrahydro-furan or pyran.  The catalysts may contain 0.01 to 20 per cent of metal and may be used in a fixed or fluid bed. Reaction is preferably effected at 300-420 DEG  C. under atmospheric or moderately elevated pressure and with a space velocity of 0.1 to 2.5 vols. of liquid feed per vol. of catalyst per hour. Examples describe the conversion of (1) 2,5-dimethyl tetrahydrofuran to methyl n-butyl ketone and a minor amount of 2,5-dimethyl furan using platinum, palladium, gold, silver, cobalt, nickel, iron or copper on activated carbon as catalyst, comparative experiments being given showing the lower or zero yields obtained when using copper on pumice, zinc oxide-sodium carbonate on coke or a sulphonated polystyrene type ion exchange resin as catalyst; (2) 2-methyl tetrahydrofuran to pantanone-2; (3) 2,4-epoxyheptane to the heptanones-2 and 4; (4) 2-methyl-5-ethyl tetrahydrofuran to heptanone-2; and (5) 1,2-epoxy cyclohexane to cyclohexanone.  Numerous other suitable epoxides are mentioned including 2,5-epoxy pentane, 3,4-epoxyhexanone; 2,3,4,5-tetramethyl, 2,3,4-tripropyl and 2-propyl 5-n-butyl tetrahydrofurans and 2,6-diethyl and 2-methyl-3,4,6-tripropyl tetrahydro pyrans. Comparative experiments are described showing that the use of a 5 per cent copper-on-activated-carbon catalyst under the condition of the reaction cause the conversion of tetrahydrofuran and 1,2-epoxybutane to n-butyraldehyde and of propylene oxide to propionaldehyde, acetone and allyl alcohol.ALSO:Catalysts for use in the isomerization of saturated epoxides to ketones (see Group IV (b)) contain a metal from Group Ib or VIII of the Periodic Table supported on an activated carbon base and may be prepared by impregnating activated carbon having a surface area of about 100 to 1000 m2/g. with an aqueous solution of a salt of the metal, e.g. the chloride or nitrate, drying the resulting paste in an inert atmosphere and then reducing it with hydrogen at about 400 DEG  to 450 DEG  C. to deposit the catalytic metal on the base.  The metal concentration may vary from 0.01 to 20 per cent.  Examples mention copper, silver, gold, iron, cobalt, nickel, palladium and platinum catalysts supported on active carbon. Reference is made in comparative isomerizations to the use of copper on pumice and 94 per cent zinc oxide-6 per cent sodium carbonate on coke.