Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
2001-02-21
2002-12-31
Trinh, Ba K. (Department: 1625)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
C549S533000
Reexamination Certificate
active
06500967
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a catalyst that is suitably used for producing an epoxide by partial oxidation of an olefin compound with use of molecular oxygen in the presence of a reducing substance such as molecular hydrogen, a method for producing the foregoing catalyst for use in production of an epoxide (hereinafter referred to as epoxide-production-use catalyst), and a method for producing an epoxide by using the epoxide-production-use catalyst.
BACKGROUND OF THE INVENTION
An epoxide producing method in which an olefin compound is partially oxidized with molecular oxygen in the presence of a reducing substance such as molecular hydrogen with use of a catalyst made of a titanium-containing oxide with gold fine particles fixed thereto, so as to produce an epoxide corresponding to the foregoing olefin compound, has been conventionally known (the Japanese Publications for Laid-Open Patent Applications No. 127550/1996 [Publication Date: May 21, 1996], 5590/1998 [Publication Date: Jan. 13, 1998], 244156/1998 [Publication Date: Sep. 14, 1998], and 128743/1999 [Publication Date: May 18, 1999] (Tokukaihei 8-127550, 10-5590, 10-244156, and 11-128743), and U.S. Pat. No. 5,939,569, etc.).
The foregoing catalyst exhibits a certain degree of activity at an initial stage of epoxidation, but the activity lowers as the reaction time has passed. Therefore, the catalyst presents a problem that its activity becomes insufficient when the reaction becomes in a steady state. Further, it also presents a problem that regeneration of the activity is hardly achieved even if a high-temperature heat treatment in an oxygen-containing gas for reactivation of the catalyst is applied to the catalyst whose activity has lowered.
SUMMARY OF THE INVENTION
The present invention was made in light of the foregoing problem in prior art, and an object of the present invention is to provide an epoxide-production-use catalyst that is, for instance, suitably used in partial oxidation of an unsaturated hydrocarbon to produce an epoxide corresponding to the unsaturated hydrocarbon, a method for producing the catalyst, and a method for producing an epoxide with use of the catalyst for epoxide production.
The inventors of the present invention studied the foregoing conventional catalysts, with view to solving the aforementioned problems. Consequently, they discovered that a cause of deactivation of the catalyst formed by fixing gold fine particles to a carrier containing an oxide containing at least one of titanium and zirconium is mainly related to the properties of acidic sites of the catalyst per se.
More specifically, an epoxide produced in epoxidation of an olefin is easily isomerized according to the acidic sites of the epoxide-production-use catalyst, thereby becoming an aldehyde corresponding thereto. For instance, in the case where propylene oxide is produced, propionaldehyde is produced by the foregoing isomerization. Further, in the case where the propionaldehyde resulting from the isomerization was solely brought into contact with the foregoing epoxide-production-use catalyst, an increase in the weight of the epoxide-production-use catalyst per se was observed. Further, in the case where epoxidation of propylene was carried out with use of the epoxide-production-use catalyst having been brought into contact with propionaldehyde, explicit deactivation was observed. Thus, it was found that aldehydes produced by isomerization condensed or polymerized at the acidic sites thereby becoming condensates or polymers that cover the active sites and impair the activity of the epoxide-production-use catalyst.
The inventors of the present application further made earnest study about the foregoing epoxide-production-use catalyst. As a result, among indices indicative of the properties of acidic sites, “acid quantity (for detailed explanation, see the head of the “DESCRIPTION OF THE EMBODIMENTS” section)” that is derived from a quantity of, among ammonium that has been adsorbed on the foregoing epoxide-production-use catalyst, a portion desorbed from the same is particularly significant for maintenance of catalyst activity and also regeneration of the activity.
More specifically, the epoxide-production-use catalyst in accordance with the present invention is composed of (i) a carrier containing an oxide containing at least one of titanium and zirconium, and (ii) gold fine particles fixed onto the carrier, and is arranged so as to have an acid quantity of not more than 0.1 mmol/g, the acid quantity being derived from a quantity of ammonium that, having been adsorbed on the catalyst at temperature of 50° C., is desorbed from the catalyst as the temperature rises from 50° C. to 400° C.
The epoxide-production-use catalyst arranged as above enables production of an epoxide with a high yield and a high selectivity, and further, exhibits good catalyst performance, such as less deactivation. In other words, the present invention ensures that an epoxide-production-use catalyst is provided that is suitably used for partial oxidation of an unsaturated hydrocarbon with molecular oxygen in the presence of a reducing substance so as to produce an epoxide, that is superior in activity and selectivity, and that exhibits less deactivation and easy regeneration of activity.
Furthermore, a method for producing the epoxide-production-use catalyst in accordance with the present invention is a method including the step of fixing gold fine particles to a carrier, the carrier containing an oxide that contains at least one of titanium and zirconium and having an acid quantity of not more than 0.15 mmol/g, the acid quantity being derived from a quantity of ammonium that, having been adsorbed on the catalyst at temperature of 50° C., is desorbed from the catalyst as the temperature rises from 50° C. to 400° C. This method makes it possible to produce the catalyst having excellent performance.
Furthermore, a method for producing an epoxide in accordance with the present invention includes the step of partial oxidation of an unsaturated hydrocarbon with molecular oxygen in the presence of a reducing substance, with use of a catalyst, the catalyst being arranged so as to include a carrier containing an oxide containing at least one of titanium and zirconium as well as gold fine particles fixed onto the carrier, and to have an acid quantity of not more than 0.1 mmol/g, the acid quantity being derived from a quantity of ammonium that, having been absorbed in the catalyst at temperature of 50° C., is desorbed from the catalyst as the temperature rises from 50° C. to 400° C. This method makes it possible to produce an epoxide from an unsaturated hydrocarbon with a high yield.
For a fuller understanding of the nature and advantages of the invention, reference should be made to the ensuing detailed description.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
An epoxide-production-use catalyst in accordance with the present invention (hereinafter referred to simply as “catalyst in accordance with the present invention” as required) is a catalyst that is obtained by fixing gold fine particles to a carrier containing an oxide containing at least one of titanium and zirconium, (hereinafter referred to simply as “gold-fine-particles-containing catalyst” as required), and that catalyst has an acid quantity, described below, of not more than 0.1 mmol/g. First of all, the definition of “acid quantity” and a measurement method of the same in the present invention will be described below.
Measurement of the acid quantity was performed employing TPD-70 (trade name, available from BEL JAPAN INC.) as measuring apparatus, in the following manner. First of all, about 0.5 g (W g) of a sample of acid quantity measurement (hereinafter referred to as measurement object) was accurately weighed and brought into the foregoing measuring apparatus. Subsequently, the sample was held at 280° C. for 30 minutes while helium gas was flown through the measuring apparatus at flow rate of Soml/minute, so that water adsorbed on th
Hayashi Toshio
Inagaki Takahiro
Wada Masahiro
Nippon Shokubai Co. , Ltd.
Nixon & Vanderhye P.C.
Presta Frank P.
Trinh Ba K.
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