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US 5,856,534 AGranted
Epoxidation process using supported silver catalysts treated with carbon dioxide
AssigneeArco Chemical Technology, L.P.
InventorsBernard Cooker, Anne M. Gaffney, Jennifer D. Jewson, Andrew P Kahn
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Abstract
The catalytic performance of a supported silver catalyst in a propylene epoxidation process is improved by first contacting the catalyst at an elevated temperature with a treatment stream comprised of carbon dioxide. The carbon dioxide-treated catalyst is thereafter contacted with a feedstream containing propylene, molecular oxygen, but essentially no carbon dioxide under conditions effective to form propylene oxide.
Claims20
A method of operating a propylene epoxidation process comprising:
- (a) contacting a supported silver catalyst with a treatment stream comprised of carbon dioxide in the vapor phase at a temperature of from 150.degree. C. to 350.degree. C. for a time effective to improve the catalytic performance of the supported silver catalyst, wherein the supported silver catalyst is comprised of (i) an inert refractory solid support, (ii) a catalytically effective amount of metallic silver, and (iii) a promoting amount of a potassium promoter derived from a potassium salt comprising potassium cation and a nitrogen oxyanion or precursor thereof;
- and
- (b) contacting the supported silver catalyst with a feedstream comprised of propylene and molecular oxygen and essentially free of carbon dioxide in the presence of a source of chloride for a time and at a temperature effective to form propylene oxide.
A method of operating a propylene epoxidation process comprising:
- (a) contacting a supported silver catalyst with a treatment stream comprised of at least 5 volume percent carbon dioxide in the vapor phase at a temperature of from 200.degree. C. to 300.degree. C. for a time effective to improve the catalytic performance of the supported silver catalyst, wherein the supported silver catalyst is comprised of (i) an inert refractory support comprised of an alkaline earth metal carbonate, (ii) from 10 to 60 weight percent metallic silver, and (iii) a promoting amount of a potassium promoter derived from a potassium salt selected from the group consisting of potassium nitrate, potassium nitrite, potassium carbonate, potassium bicarbonate and mixtures thereof;
- and
- (b) contacting the supported silver catalyst with a feedstream comprised of propylene and molecular oxygen and essentially free of carbon dioxide in the presence of a source of chloride selected from the group consisting of C.sub.1 -C.sub.10 organic chloride compounds, inorganic chloride compounds, and combinations thereof at a temperature of from 200.degree. C. to 300.degree. C. for a time effective to form propylene oxide.
Dependencies are inferred from the claim text.