Epoxidation process
AssigneeArco Chemical Technology, L.P.
InventorsRobert J. Saxton, John G. Zajacek, Guy L. Crocco
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Abstract
A crystalline molecular sieve having a framework structure isomorphous with zeolite beta and containing Si and Ti, but essentially no framework Al, usefully catalyzes olefin epoxidation wherein hydrogen peroxide is the oxidant.
Claims13
A process for epoxidation of a C.sub.2 -C.sub.10 aliphatic mono-olefin comprising contacting said mono-olefin with hydrogen peroxide in a liquid phase in the presence of a catalytically effective amount of a crystalline titanium-containing molecular sieve at a temperature of from 25.degree. C. to 120.degree. C. for a time effective to selectively form an epoxide of the mono-olefin, wherein the crystalline titanium-containing molecular sieve is characterized by a framework structure isomorphous to zeolite beta comprised of Si and Ti, but less than 1000 ppm framework Al, corresponding to the general formula SiO.sub.2 :yTiO.sub.2 wherein y is from 0.01 to 0.25 and is prepared by a method comprising:
- (a) contacting a zeolite beta comprised of Si and Al with a mineral acid at a temperature of from 20.degree. C. to 200.degree. C. for a time necessary to extract essentially all of the Al from the framework of the zeolite beta to form a dealuminated zeolite beta having a Si:Al molar ratio equal to or greater than about 750;
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- (b) contacting the dealuminated zeolite beta with a volatile titanium compound at a temperature of from about 100.degree. C. to 850.degree. C.
The process of claim 8 wherein the volatile titanium compound is TiCl.sub.4.
A process for epoxidation of propylene comprising contacting propylene with hydrogen peroxide in a liquid phase comprising an alcohol solvent in the presence of a crystalline titanium-containing molecular sieve at a temperature of from 25.degree. C. to 120.degree. C. for a time effective to selectively form propylene oxide, wherein the crystalline titanium-containing molecular sieve is characterized by a framework structure isomorphous to zeolite beta comprised of Si and Ti, but less than 500 ppm Al, corresponding to the general formula SiO.sub.2 :yTiO.sub.2 wherein y is from 0.01 to 0.25 having a titanium content of from 1 to 10 weight percent and prepared by a method comprising:
- (a) contacting a zeolite beta comprised of Si and Al with nitric acid at a temperature of 25.degree. C. to 150.degree. C. for a time necessary to extract essentially all of the Al from the framework of the zeolite beta to form a dealuminated zeolite beta having a Si:Al molar ratio equal to or greater than about 1000;
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- (b) contacting the dealuminated zeolite beta with titanium tetrachloride at a temperature of from 250.degree. C. to 750.degree. C.
Dependencies are inferred from the claim text.