Process for propylene oxide
First Claim
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1. A PROCESS FOR THE PPRODUCTION OF PROPYLENE OXIDE COMPRISING REACTING PROPYLENE AND A MOLECULAR OXYGEN CONTAINING GAS IN THE VAPOR PHASE AT A TEMPERATURE BETWEEN ABOUT 180* TO 300*C AND AT A PRESSURE BETWEEN 1 AND 20 ATMOSPHERES IN THE PRESENCE OF A CATALYST COMPOSITION COMPRISING ELEMENT SILVER MODIFIED ON ITS SURFACE BY AN ADDITIVE WHICH IS A COOMPOUND OF A GROUP VB OR GROUP VIB METAL, THE AMOUNT OF SAID ADDITIVE ON THE SURFACE OF SAID ELEMENTAL SILVER IS FROM 1 X 10**6 TO 100 X 10**6 GRAM MOLES PER GRAM OF SILVER HAVING A SURFACE AREA OF ONE SQUARE METER.
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Abstract
This case relates to a process for the production of propylene oxide by oxidising propylene in the presence of an elemental silver catalyst which is modified on the surface by an additive which is a compound of a group VB or Group VIB metal.
13 Citations
21 Claims
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1. A PROCESS FOR THE PPRODUCTION OF PROPYLENE OXIDE COMPRISING REACTING PROPYLENE AND A MOLECULAR OXYGEN CONTAINING GAS IN THE VAPOR PHASE AT A TEMPERATURE BETWEEN ABOUT 180* TO 300*C AND AT A PRESSURE BETWEEN 1 AND 20 ATMOSPHERES IN THE PRESENCE OF A CATALYST COMPOSITION COMPRISING ELEMENT SILVER MODIFIED ON ITS SURFACE BY AN ADDITIVE WHICH IS A COOMPOUND OF A GROUP VB OR GROUP VIB METAL, THE AMOUNT OF SAID ADDITIVE ON THE SURFACE OF SAID ELEMENTAL SILVER IS FROM 1 X 10**6 TO 100 X 10**6 GRAM MOLES PER GRAM OF SILVER HAVING A SURFACE AREA OF ONE SQUARE METER.
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2. A process according to claim 1 wherein the gaseous reaction mixture contains an inert gaseous diluent in the range of 0 to 97% by volume selected from the group consisting of helium, nitrogen, and argon.
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3. A process according to claim 1 wherein the amount of propylene in the gaseous mixture is between 2 and 20% or between 60 and 80% by volume.
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4. A process according to claim 1 wherein the contact time of the reaction is in the range 0.1 to 60 seconds.
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5. A process according to claim 1 wherein the metal in the Group VB metal compound is selected from vanadium, niobium and tantalum and in the Group VIB metal compound is selected from chromium, molybdenum and tungsten.
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6. A process according to claim 1 wherein the Group VB or Group VIB metal in the additive is in the cationic portion of the metal compound.
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7. A process according to claim 6 wherein the Group VB or Group VIB metal compound in the additive is a halide selected from a chloride and a bromide.
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8. A process according to claim 7 wherein the Group VB metal halide is vanadium trichloride and the Group VIB metal halide is selected from chromium trichloride, chromyl chloride, molybdenum pentachloride and tungsten hexachloride.
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9. A process according to claim 1 wherein the Group VB or Group VIB metal in the additive is in the anionic portion of the metal compound.
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10. A process according to claim 9 wherein the metal compound is selected from an alkali metal chromate and an alkali metal dichromate.
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11. A process according to claim 10 wherein the alkali metal is potassium.
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12. A process according to claim 1 wherein the amount of additive on the surface of elemental silver is between 1 X 10 6 and 20 X 10 6 gram moles per gram of silver having a surface area of 1 square metre for an additive in which the metal is in the cationic portion of the metal compound.
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13. A process according to claim 1 wherein the elemental silver in the catalyst composition has a surface area of up to 120 m2 per gram.
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14. A process according to claim 1 wherein the catalyst composition is supported on an inert material selected from alumina, pumice, silica and silicon carbide.
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15. A process according to claim 1 wherein the propylene oxide produced is recovered from the reaction mixture by passing the reaction gases into a gas/liquid scrubbing agent to absorb the oxide, followed by distillation.
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16. A process according to claim 15 wherein the scrubbing agent is selected from cooled ethanol, water, and an ester of ethylene glycol or propylene glycol.
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17. A process according to claim 1 wherein the catalyst is activated by treatment thereof with a halogenated hydrocarbon selected from 1,2-dichloroethene, 1,1,2-trichloroethane and 3-chloropropene.
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18. A process according to claim 1 wherein said additive is a compound of a Group VB metal.
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19. A process according to claim 1 wherein said additive is vanadium trichloride, tantalum pentachloride, niobium pentachloride, or niobium pentabromide.
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20. A process as claimed in claim 1 wherein said additive is a compound of a Group VIB metal.
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21. A process as defined in claim 20 wherein said Group VIB metal compound is chromium trichloride, chromyl chloride, molybdenum pentachloride, tungsten hexachloride, sodium chromate, potassium chromate, potassium dichromate or chromyl bromide.
Specification
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Current AssigneeAlexander John Kolombos, Colin Christopher Mccain, Eric Andrew Porter
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Original AssigneeAlexander John Kolombos, Colin Christopher Mccain, Eric Andrew Porter
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InventorsKolombos, Alexander John, McCain, Colin Christopher, Porter, Eric Andrew
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Primary Examiner(s)Milestone, Norma S.
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Application NumberUS05/370,923Time in Patent Office722 DaysField of Search260/348.5R,348.5VUS Class Current549/536CPC Class CodesB01J 23/68 with arsenic, antimony, bis...C07D 301/10 with catalysts containing s...Y02P 20/52 using catalysts, e.g. selec...
