US20110152547A1

US20110152547A1 - Process for producing olefin oxide

Info

Publication number: US20110152547A1
Application number: US12/826,458
Authority: US
Inventors: Selim SENKAN; Anusorn Seubsai
Original assignee: Sumitomo Chemical Co Ltd
Current assignee: Sumitomo Chemical Co Ltd
Priority date: 2009-12-17
Filing date: 2010-06-29
Publication date: 2011-06-23
Also published as: EP2513074A4; CN102933566B; WO2011075459A1; BR112012014674A8; CN102652130A; KR101763966B1; US8822372B2; KR20120115269A; US20120283454A1; KR20120104253A; BR112012014674A2; JP2013505985A; JP2013505984A; BR112012017167A2; EP2513073A1; CN102933566A; EP2513073A4; US20120283455A1; WO2011075458A1; EP2513074A1

Abstract

A process for producing an olefin oxide which comprises reacting an olefin with oxygen in the presence of a catalyst comprising (a) copper oxide, (b) ruthenium metal or ruthenium oxide and (c) alkaline metal component or alkaline earth metal component.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application has priority from U.S. provisional application No. 61/204,324 filed Dec. 17, 2009, disclosures of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a process for producing an olefin oxide.

BACKGROUND ART

Olefin oxides, such as propylene oxide, are important and versatile intermediates used in the production of a large variety of valuable consumer products such as polyurethane foams, polymers, alkylene glycol, cosmetics, food emulsifiers and as fumigants and insecticides.
Previous research on olefin epoxidation involved the use of Ag-based catalysts (Appl. Catal. A. Gen. 2001, 221, 73), as well as silica supported Cu (J. Catal. 2005, 236, 401), various metal oxides (Appl. Catal. A. Gen. 2007, 316, 142), Au-based catalysts with H₂as a co-reactant (Ind. & Eng. Chem. Res. 1995, 34, 2298, J. Catal. 1998, 178, 566; Appl. Catal. A. Gen. 2000, 190, 43; Angew. Chem. Int. Ed. 2004, 43, 1546), titania based catalysts that deactivated quickly (Catal. Commun. 2001, 1356; Catal. Commun. 2003, 4, 385), molten salts of metal nitrates (Appl. Catal. A. Gen. 2000, 196, 217), the use of O₃(Appl. Catal A. Gen. 2000, 196, 217) and nitrous oxide (Ind. & Eng. Chem. Res. 1995, 34, 2298) as reactants. Although these developments are scientifically interesting, they have serious drawbacks, such as low PO selectivities and/or low propylene conversions, short catalyst lifetimes, the use of higher pressures or the use of costly co-reactants (Appl. Catal. A. Gen. 2007, 316, 142).

SUMMARY OF THE INVENTION

The present invention provides:
[1] A process for producing an olefin oxide which comprises reacting an olefin with oxygen in the presence of a catalyst comprising (a) copper oxide, (b) ruthenium metal or ruthenium oxide and (c) alkaline metal component or alkaline earth metal component.
[2] The process according to [1], wherein the catalyst comprises (d) halogen component.
[3] The process according to [1], wherein (a) copper oxide, (b) ruthenium metal or ruthenium oxide and (c) alkaline metal component or alkaline earth metal component are supported on a porous support.
[4] The process according to [2], wherein (a) copper oxide, (b) ruthenium metal or rutheniumoxide, (c) alkaline metal component or alkaline earth metal component and (d) halogen component are supported on a porous support.
[5] The process according to [3] or [4], wherein the porous support comprises Al₂O₃, SiO₂, TiO₂or ZrO₂.
[6] The process according to [3] or [4], wherein the porous support comprises SiO₂.
[7] The process according to any one of [1] to [6], wherein the total amount of (a) copper oxide, (b) ruthenium metal or ruthenium oxide and (c) alkaline metal component or alkaline earth metal component is 0.01 to 80% by weight of the amount of the catalyst.
[8] The process according to any one of [1] to [7], wherein the copper/ruthenium metal molar ratio in the catalyst is 1/99 to 99/1.
[9] The process according to any one of [1] to [8], wherein the ruthenium/(c) component metal molar ratio in the catalyst is 1/99 to 99/1.
[10] The process according to any one of [1] to [9], wherein (a) copper oxide is CuO.
[11] The process according to any one of [1] to [10], wherein (b) ruthenium metal or ruthenium oxide is RuO₂.
[12] The process according to any one of [1] to [11], wherein (c) alkaline metal component or alkaline earth metal component is an alkaline metal-containing compound.
[13] The process according to any one of [1] to [12], wherein (c) alkaline metal component or alkaline earth metal component is a sodium-containing compound.
[14] The process according to [3], wherein the catalyst is obtained by impregnating a porous support with a solution containing a copper ion, a ruthenium ion and an alkaline metal or alkaline earth metal ion to prepare a composition, followed by calcining the composition.
[15] The process according to [3] or [4], wherein the catalyst is obtained by impregnating a porous support with a solution containing a copper ion, a ruthenium ion, an alkaline metal or alkaline earth metal ion and a halogen ion to prepare a composition, followed by calcining the composition.
[16] The process according to any one of [1] to [15], wherein the olefin is propylene and the olefin oxide is propylene oxide.
[17] The process according to any one of [1] to [16], which comprises reacting an olefin with oxygen at a temperature of 100 to 350′C.
[18] A catalyst for production of an olefin oxide which comprises (a) copper oxide, (b) ruthenium metal or ruthenium oxide and (c) alkaline metal component or alkaline earth metal component.
[19] The catalyst according to [18] which comprises (d) halogen component.
[20] The catalyst according to [18], wherein (a) copper oxide, (b) ruthenium metal or ruthenium oxide and (c) alkaline metal component or alkaline earth metal component are supported on a porous support.
[21] The catalyst according to [19], wherein (a) copper oxide, (b) ruthenium metal or ruthenium oxide, (c) alkaline metal component or alkaline earth metal component and (d) halogen component are supported on a porous support.
[22] The catalyst according to [20] which is obtained by impregnating a porous support with a solution containing a copper ion, a ruthenium ion and an alkaline metal or alkaline earth metal ion to prepare a composition, followed by calcining the composition.
[23] The catalyst according to [20] or [21] which is obtained by impregnating a porous support with a solution containing a copper ion, a ruthenium ion, an alkaline metal or alkaline earth metal ion and halogen ion to prepare a composition, followed by calcining the composition.
[24] The catalyst according to any one of [18] to [23], wherein (c) alkaline metal component or alkaline earth metal component is an alkaline metal-containing compound.
[25] The catalyst according to any one of [20] to [24], wherein the porous support comprises Al₂O₃, SiO₂, TiO₂or ZrO₂.
[26] The catalyst according to any one of [20] to [25], wherein the porous support comprises SiO₂.
[27] The catalyst according to any one of [18] to [26], wherein the olefin oxide is propylene oxide.
[28] Use of a catalyst for producing an olefin oxide, said catalyst comprising (a) copper oxide, (b) ruthenium metal or rutheniumoxide and (c) alkaline metal component or alkaline earth metal component.
[29] The use of a catalyst according to [28], wherein the olefin oxide is propylene oxide.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a graph showing the result of Example 1.

FIG. 2 is a graph showing the result of Example 2.

FIG. 3 is a graph showing the result of Example 3.

FIG. 4 is a graph showing the result of Example 4.

FIG. 5 is a graph showing the result of Example 5.

FIG. 6 is a graph showing the XRD patterns of Example 6.

DETAILED DESCRIPTION OF THE INVENTION

The process of the present invention comprises reacting an olefin with oxygen in the presence of a catalyst comprising (a) copper oxide, (b) ruthenium metal or ruthenium oxide and (c) alkaline metal component or alkaline earth metal component. In the catalyst, the components (a), (b) and (c) are preferably supported on a porous support. This catalyst is valuable for production of olefin oxides, which is one aspect of the present invention.
The porous support has pores capable of supporting the components (a), (b) and (c). The porous support comprises preferably Al₂O₃, SiO₂, TiO₂, or ZrO₂, more preferably SiO₂. Examples of the porous support comprising SiO₂include mesoporous silica. Such a porous support may also comprise zeolites.
If the catalyst comprises SiO₂as a support, olefin oxides can be prepared with good yield and good selectivity.
The catalyst may comprise one or more kinds of (a) copper oxide.
The (a) copper oxide is usually composed of copper and oxygen.
Examples of the copper oxide include Cu₂O and CuO. The copper oxide is preferably CuO.
The catalyst may comprise one or more kinds of (h) ruthenium metal or ruthenium oxide. The (b) ruthenium oxide is usually composed of ruthenium and oxygen. Examples of the ruthenium oxide include RuO₄, and RuO₂. The component (b) is preferably RuO₂.
The catalyst may comprise one or more kinds of (c) alkaline metal component or alkaline earth metal component.
The component (c) may be an alkaline metal-containing compound, an alkaline earth metal-containing compound, an alkaline metal ion or an alkaline earth metal ion.
Examples of the alkaline metal-containing compound include compounds containing an alkaline metal such as Na, K, Rb and Cs. Examples of the alkaline earth metal-containing compound include compounds containing an alkaline earth metal such as Ca, Mg, Sr and Ba. Examples of the alkaline metal ion include Na⁺, K⁺, Rb⁺ and Cs⁺. Examples of the alkaline earth metal ion include such as Ca²⁺, Mg²⁺, Sr²⁺ and Ba²⁺.
The component (c) is preferably an alkaline metal-containing compound, more preferably a sodium-containing compound.
The alkaline metal-containing compound and alkaline earth metal-containing compound are preferably an alkaline metal salt and an alkaline earth metal salt. The alkaline metal salt comprises the alkaline metal ion as mentioned above with an anion. The alkaline earth metal salt comprises the alkaline earth metal ion as mentioned above with an anion. Examples of anions in such salts include Cl, Br⁻, I⁻, NO₃ ⁻, SO₄ ²⁻ and CO₃ ²⁻. Such salts are preferably an alkaline metal salt with a halogen, such as an alkaline metal halide, or an alkaline earth metal-containing salt with a halogen, such as an alkaline earth metal halide, more preferably an alkaline metal salt with a halogen, still more preferably an alkaline metal chloride.
The catalyst comprises preferably CuO, RuO₂and an alkaline metal-containing compound, still more preferably CuO, RuO₂and a sodium-containing compound, because the olefin oxide yield and selectivity can be improved by adopting such combination to the production of an olefin oxide. Particularly if the catalyst comprises NaCl, as the (c) component, it can show excellent olefin oxide selectivity.
The copper/ruthenium metal molar ratio in the catalyst is preferably 1/99 to 99/1. When the metal molar ratio falls within such a range, the olefin oxide yield and selectivity can be further improved. The lower limit of the molar ratio is more preferably 2/98, still more preferably 3/97. The upper limit of the molar ratio is more preferably 98/2, still more preferably 97/3.
The ruthenium/(c) component molar ratio in the catalyst is preferably 1/99 to 99/1. When the molar ratio falls within such a range, the olefin oxide yield and selectivity can be further improved. The lower limit of the molar ratio is more preferably 2/98, still more preferably 3/97. The upper limit of the molar ratio is more preferably 98/2, still more preferably 97/3. The “(c) component” of the molar ratio represents the alkaline metal or alkaline earth metal existing in the (c) component and the alkaline metal or alkaline earth metal ion existing in the (c) component.
When the components (a), (b) and (c) are supported on a porous support in the catalyst, the total content of the components (a), (b) and (c) is preferably 0.01 to 80% by weight of the amount of the catalyst. When the total content falls within such a range, the olefin oxide yield and selectivity can be further improved. The lower limit of the total content is more preferably 0.05% by weight, still more preferably 0.1% by weight of the amount of the catalyst. The upper limit of the total content is more preferably 50% by weight, still more preferably 30% by weight of the amount of the catalyst.
The catalyst may comprise (d) halogen component besides the components (a), (b) and (c). The component (d) is generally a halogen-containing compound. Examples of the halogen include chlorine, fluorine, iodine and bromine.
Examples of such a halogen-containing compound include halides of copper or ruthenium and oxyhalides of copper or ruthenium. If the catalyst comprises the component (d), the component may be supported on the porous support as mentioned above.
Production of the catalyst is not restricted to a specific process, examples of which include the conventional methods.
When the components (a), (b) and (c) are supported on a porous support in the catalyst, the catalyst can be obtained by impregnating a porous support with a solution containing a copper ion, a ruthenium ion and an alkaline metal or alkaline earth metal-containing ion to prepare a composition, followed by calcining the composition. The support can be in form of powder, or shaped to a desired structure as necessary. If the catalyst comprises component (c) which is an alkaline metal salt with a halogen or alkaline earth metal salt with a halogen, and the component (d) supported on the porous support, the catalyst can be obtained in the same procedure as mentioned above except that solution contains copper ion, a ruthenium ion, an alkaline metal or alkaline earth metal-containing ion and a halogen ion.
The solution containing a copper ion, a ruthenium ion and an alkaline metal or alkaline earth metal ion can be prepared by dissolving a copper metal salt, a ruthenium metal salt and an alkaline metal or alkaline earth metal salt in a solvent. Examples of the copper metal salt include copper acetate, copper ammonium chloride, copper bromide, copper carbonate, copper ethoxide, copper hydroxide, copper iodide, copper isobutyrate, copper isopropoxide, copper oxalate, copper oxychloride, copper nitrates, and copper chlorides. Examples of the ruthenium metal salt include, for example, a halide such as ruthenium bromide, ruthenium chloride, ruthenium iodide, an oxyhalide such as Ru₂OCl₄, Ru₂OCl₅and Ru₂OC₁₆, a halogeno complex such as [RuCl₂(H₂O)₄]Cl, an ammine complex such as [Ru(NH₃)₅H₂O]Cl₂, [Ru(NH₃)₅Cl]Cl₂, [Ru(NH₃)₆]Cl₂and [Ru(NH₃)₆]Cl₃, a carbonyl complex such as Ru(CO)₅and Ru₃(CO)₁₂, a carboxylate complex such as [Ru₃O(OCOCH₃)₆(H₂O)₃], ruthenium nitrosylchloride, and [Ru₂(OCOR)₄]Cl(R=alkyl group having 1 to 3 carbon atoms), a nitrosyl complex such as [Ru(NH₃)₅(NO)]Cl₃, [Ru(OH)(NH₃)₄(NO)](NO₃)₂and [Ru(NO)](NO₃)₃, an amine complex, an acetylacetonate complex, and ammonium salt such as (NH₄)₂RuCl₆. The alkaline metal or alkaline earth metal salt for the solution may be the same as or different from the (c) component. Examples of the alkaline metal or alkaline earth metal salt include alkaline metal nitrates, alkaline earth metal nitrates, alkaline metal halides and alkaline earth metal halides, preferably alkaline metal halides and alkaline metal nitrates, more preferably NaNO₃and NaCl. At least one of the metal salts for the solvent contains preferably a halogen ion, more preferably a chloride ion. Such a halogen ion may form the (c) component such as NaCl and the (d) component such as halides and oxyhalides of Cu or Ru. The solution may contain acidic or basic compounds in order to control its pH.
Examples of the solvent for the solution include water and alcohols such as methanol or ethanol.
The total amount of the porous support is preferably 20 to 99.99% by weight, more preferably 50 to 99.5% by weight, still preferably 70 to 99.9% by weight of the catalyst as obtained.
The composition as prepared by the impregnation is preferably dried at a temperature of approximately 40° C. to approximately 20° C. before calcining the composition. Drying may be performed under an atmosphere of air or also under an inert gas atmosphere (for example, Ar, N₂, He) at standard pressure or reduced pressure. A drying time is preferably in the range from 0.5 to 24 hours. After drying, the composition can be shaped to a desired structure as necessary.
Calcining the composition is not limited, but preferably may be performed under a gas atmosphere containing oxygen. Examples of such a gas stream include air and an oxygen gas. The gas may be used after being mixed at an appropriate ratio with a diluting gas such as nitrogen, helium, argon, and water vapor. An optimal temperature for calcination varies depending on the kind of the gas and the composition, however, a too high temperature may cause agglomeration of ruthenium oxide and copper oxide. Accordingly, the calcination temperature is typically 200 to 800° C., preferably 400 to 600° C.
The catalyst can be used as powder, but it is usual to shape it into desired structures such as spheres, pellets, cylinders, rings, hollow cylinders or stars. The catalyst can be shaped by a known procedure such as extrusion, ram extrusion, tableting. The calcination is normally performed after shaping into the desired structures, but it can also be performed before shaping them.
Next, the following explains a reaction of an olefin with oxygen in the presence of the catalyst as described above.
In the present invention, the olefin may have a linear or branched structure and contains usually 2 to 10, preferably 2 to 8 carbon atoms. Examples of the olefin include preferably ethylene, propylene, butene, pentene, hexene, heptene and octene, more preferably ethylene, propylene and butene, still more preferably propylene.
The reaction is generally performed in the gas phase. In the reaction, the olefin and oxygen may be fed respectively in the form of a gas. Olefin and oxygen gases can be fed in the form of their mixed gas. Olefin and oxygen gases may be fed with diluent gases. Examples of diluent gases include nitrogen or rare gases, such as argon and helium.
As the oxygen source, pure oxygen may be used, or a mixed gas containing a gas inactive to the reaction, such as air, may be used. The amount of oxygen used varies depending on the reaction type, the catalyst, the reaction temperature or the like. The amount of oxygen is typically 0.01 to 100 mol, and preferably 0.03 to 30 mol, and more preferably 0.25 to 10 mol, with respect to 1 mol of the olefin.
The reaction is performed at a temperature generally of 100 to 350° C., preferably of 120 to 330° C., more preferably of 170 to 310° C.
The reaction is usually carried out under reaction pressure in the range of reduced pressure to increased pressure. By carrying out the reaction under such a reaction pressure condition, the productivity and selectivity of olefin oxides can be improved. Reduced pressure means a pressure lower than atmospheric pressure. Increased pressure means a pressure higher than atmospheric pressure. The pressure is typically in the range of 0.01 to 3 MPa, and preferably in the range of 0.02 to 2 MPa, in the absolute pressure.
The reaction may be carried out as a batch reaction or a continuous reaction, preferably as a continuous reaction for industrial application. The reaction of the present invention may be carried out by mixing an olefin and oxygen and then contacting the mixture with the catalyst under reduced pressure to the increased pressure.
The reactor type is not limited. Examples of the reactor type are fluid bed reactor, fixed bed reactor, moving bed reactor, and the like, preferably fixed bed reactor. In the case of using fixed bed reactor, single tube reactor or multi tube reactor can be employed. More than one reactor can be used. If the number of reactors is large, small reactors as for example microreactors, can be used, which can have multiple channels. Adiabatic type or heat exchange type may also be used.
In the present invention, the olefin oxide may have a linear or branched structure and contains usually 2 to 10, preferably 2 to 0 carbon atoms. Examples of the olefin oxides include preferably ethylene oxide, propylene oxide, butane oxide, pentene oxide, hexene oxide, heptene oxide and octene oxide, more preferably ethylene oxide, propylene oxide and butene oxide, still more preferably propylene oxide.
The olefin oxide as obtained can be collected by a method known in the art such as separation by distillation.

EXAMPLES

In Examples 1 to 5, each measurement was performed according to the following method:
Data analysis for sample gases was conducted by an on-line Micro-Gas Chromatograph (Varian, CP-4900) equipped with a thermal conductivity detector (TCD), PoraPLOT U (10M) and Molecular sieve 13X (10M).
The detected products were propylene oxide (PO), acetone (AT), acetaldehyde (AD), CO_x(CO₂and CO), and propanal+acrolein (PaL+AC).
The propylene conversion, product selectivity, and yield (calculated as selectivity of product×propylene conversion) of products were calculated on the basis of carbon balance. Propylene conversions (X_PR) were determined from the following:
X_PR={[PO+AC+AT+2AD/3+CO₂/3]_out/[C₃H₆]_in}×100%;
and PO selectivities (S_PO) were then calculated using the following expression:
S_PO={[PO]/[PO+AC+AT+2AD/3+CO₂/3]}×100%
Note: PaL+AC are reported together since the two compounds appear at the same retention time, although the PaL is typically only found in trace amounts.

Example 1

Aqueous solutions of Ru[(NH₄)₂RuCl₆, Aldrich] and Cu [Cu(NO₃)₂, Alfa Aesar, ACS, 98.0%-102.0%] and Na[NaNO₃, Alfa Aesar, ACS, 99.0%] were mixed at a metal weight ratio of 4:2:1 (=Ru:Cu:Na), to prepare a metal salt solution for achieving 12.5 wt % (by metal atomic weight, relative to the amount of the catalyst) loading on a SiO₂support powder (surface area 145 m²/g). The metal salt solution was then allowed to impregnate the support for 24 hours in air. The resulting material was then heated at 150° C. until dried, and calcined at 500° C. for 12 hours in air.
The catalyst (5.0 mg) was placed in a well of a reactor as mentioned in Angew. Chem. Int. Ed. 38 (1999) 2794, equipped with array microreactors, wells along each reactor channel and a passivated 200 micron ID capillary sampling probe within the reactor channel. The mixture gas consisting of 1 vol % propylene (C₃H₆), 4 vol % O₂, and 95 vol % He was fed to the well containing the catalyst, at a gas hourly space velocity (GHSV) of 20,000 h⁻¹, at a reactor temperature of 190, 210, 230, 250, 260, 270, 290 or 310° C.
Gas sampling was accomplished by withdrawing reactor exit gases using the passivated 200 micron ID capillary sampling probe.
The results are shown in FIG. 1.

Example 2

The catalysts were prepared in the same manner as Example 1, except that the total metal content in the catalyst was 8% by weight. Propylene oxide was prepared in the same manner as Example 1 except that the catalysts of the present example were used, the reactor temperature was 250° C., and GHSV was changed.
The results are shown in FIG. 2.

Example 3

The catalysts were prepared in the same manner as Example 1, except that the total metal content in each of the catalysts was 5, 7, 10 or 12.5% by weight. Propylene oxide was prepared in the same manner as Example 1 except that the catalysts of the present example were used and the reactor temperature was 250° C.
The results are shown in FIG. 3.

Example 4

The catalysts were prepared in the same manner as Example 3, except that the total metal content in the catalysts was 12.5% by weight. Propylene oxide was prepared in the same manner as Example 3 except that the oxygen/propylene (volume ratio) was changed.
The results are shown in FIG. 4.

Example 5

Time-on-stream testing was conducted with the catalyst. The catalyst was prepared in the same manner as Example 4. Propylene oxide was prepared in the same manner as Example 3 except that the reactor temperature was 250° C. or 265° C.
The results are shown in FIG. 5.

Example 6

The powder x-ray diffraction pattern of the catalyst obtained in Example 1 was determined with PANalytical X'Pert PRO fitted with a Ni filter and a Soller slit collimator.
The Cu—K_αradiation at 45 kV and 40 mA was used to identify the active catalyst phase.
The following compositions were also examined in the same manner, Na₂O (1.8 wt % Na, relative to the total of Na₂O and SiO₂) supported on SiO₂which was prepared from NaNO₃; CuO (3.6 wt % Cu, relative to the total of CuO and SiO₂) supported on SiO₂which was prepared from Cu(NO₃)₂; RuO₂(7.2 wt % Ru, relative to the total of RuO₂and SiO₂) supported on SiO₂which was prepared from (NH₄)₂RuCl₆; NaCl (1.8 wt % Na, relative to the total of NaCl and SiO₂) supported on SiO₂which was prepared from NaCl; and bimetallic RuO₂+CuO supported on SiO₂which was prepared in the same manner as the catalyst except that NaCl was not used.
The XRD patterns are shown in FIG. 6. The XRD pattern of the catalyst shows that the catalyst comprises CuO, RuO₂and NaCl without forming any crystalline mixed metal oxides or alloys.

Example 7

A catalyst is prepared in the same manner as Example 1, except that TiO₂is used instead of SiO₂. Production of propylene oxide is carried out in the same manner as Example 1 except that the catalyst of the present example is used.
In Examples 8 to 15, data analysis was performed according to the following method:
A reaction gas was mixed with ethane (10 Nml/min) as an external standard, and then directly introduced into the TCD-GC equipped with a column of Gaskuropack 54 (2 m). All products in the reaction gas were collected for 1 hour with double methanol traps connected in series and cooled with a dry-ice/methanol bath. The two methanol solutions were mixed together and added to anisole as an external standard, and then analyzed with two FID-GCs equipped with different columns, PoraBOND U (25 m) and PoraBOND Q (25 m).
The propylene conversion, product selectivity, and yield of products were calculated in the same manner as Examples 1 to 5.

Example 8

The metal composition was prepared by a co-impregnation method. A predetermined weight (1.9 g) of an amorphous silica powder (SiO₂, Japan Aerosil, 380 m²/g) was added to an aqueous solution mixture containing 0.54 g of (NH₄)₂RuCl₆(Aldrich), 0.30 g of Cu(NO₃)₂of (Wako) and 0.10 g NaNO₃(Wako), followed by stirring for 24 hours in the air to impregnate the support with the metal salts. The resulting material was then heated at 100° C. until dried, and calcined at 500° C. for 12 hours in the air to give a catalyst.
The catalyst was evaluated by using a fixed-bed reactor. Filling a ½-inch reaction tube made of stainless steel with 1 mL of the thus obtained catalyst, the following gases were fed to the reaction tube to carry out the reaction: 450 NmL/h of propylene, 900 NmL/h of the air, 990 NmL/h of a nitrogen gas. Such a reaction was carried out at the reaction temperature of 200° C. under the increased pressure (equivalent to 0.3 MPa in the absolute pressure).
The result is shown in Table 1.

Example 9

The preparation and the reaction were conducted in the same manner as Example 8, except that the preparation was conducted using 0.64 g of (NH₄)₂RuCl₆(Aldrich), 0.35 g of Cu(NO₃)₂(Wako), 0.08 g of Rb(NO₃) (Wako) and 2.3 g of an amorphous silica powder (SiO₂, Japan Aerosil, 380 m²/g) as raw materials.
The result is shown in Table 1.

Example 10

The preparation and the reaction were conducted in the same manner as Example 8, except that the preparation was conducted using 0.76 g of (NH₄)₂RuCl₆(Aldrich), 0.42 g of Cu (NO₃)₂(Wako), 0.08 g of Cs(NO₃) (Wako) and 2.7 g of an amorphous silica powder (SiO₂, Japan Aerosil, 380 m²/g) as raw materials.
The result is shown in Table 1.

Example 11

The preparation and the reaction were conducted in the same manner as Example 8, except that the preparation was conducted using 0.23 g of (NH₄)₂RuCl₆(Aldrich), 0.13 g of Cu(NO₃)₂(Wako), 0.1 g of Mg(NO₃)₂(Wako) and 0.8 g of an amorphous silica powder (SiO₂, Japan Aerosil, 380 m²/g) as raw materials.
The result is shown in Table 1.

Example 12

The preparation and the reaction were conducted in the same manner as Example 8, except that the preparation was conducted using 1.0 g of (NH₄)₂RuCl₆(Aldrich), 0.58 g of Cu (NO₃)₂(Wako), 0.08 g of Ca(NO₃)₂(Wako) and 3.7 g of an amorphous silica powder (SiO₂, Japan Aerosil, 380 m²/g) as raw materials.
The result is shown in Table 1.

Example 13

The preparation and the reaction were conducted in the same manner as Example 8, except that the preparation was conducted using 0.86 g of (NH₄)₂RuCl₆(Aldrich), 0.47 g of Cu(NO₃)₂(Wako), 0.15 g of Sr(NO₃)₂(Wako) and 3.0 g of an amorphous silica powder (SiO₂, Japan Aerosil, 380 m²/g) as raw materials.
The result is shown in Table 1.

Example 14

The preparation and the reaction were conducted in the same manner as Example 8, except that the preparation was conducted using 0.73 g of (NH₄)₂RuCl₆(Aldrich), 0.40 g of Cu(NO₃)₂(Wako), 0.10 g of Ba (NO₃)₂(Wako) and 2.6 g of amorphous silica powder (SiO₂, Japan Aerosil, 380 m²/g) as raw materials.
The result is shown in Table 1.

TABLE 1

	Example

	8	9	10	11	12	13	14

alkaline metal or	Na	Rb	Cs	Mg	Ca	Sr	Ba
alkaline erath metal
reactin tempereature	200	200	200	200	200	200	200
(° C.)
propylene conversion	0.7	0.6	0.3	0.6	0.4	0.4	0.5
(%)
propylene oxide	22	13	8	5	8	7	9
selectivity (%)

Example 15

A catalyst is prepared in the same manner as example 8, except that TiO₂is used instead of SiO₂. Production of propylene oxide is carried out in the same manner as Example 8 except that the catalyst of the present example is used.

Claims

1. A process for producing an olefin oxide which comprises reacting an olefin with oxygen in the presence of a catalyst comprising (a) copper oxide, (b) ruthenium metal or ruthenium oxide and (c) alkaline metal component or alkaline earth metal component.

2. The process according to claim 1, wherein the catalyst comprises (d) halogen component.

3. The process according to claim 1, wherein (a) copper oxide, (b) ruthenium metal or ruthenium oxide and (c) alkaline metal component or alkaline earth metal component are supported on a porous support.

4. The process according to claim 2, wherein (a) copper oxide, (b) ruthenium metal or ruthenium oxide, (c) alkaline metal component or alkaline earth metal component and (d) halogen component are supported on a porous support.

5. The process according to claim 3 or 4, wherein the porous support comprises Al₂O₃, SiO₂, TiO₂or ZrO₂.

6. The process according to claim 3 or 4, wherein the porous support comprises SiO₂.

7. The process according to claim 1 or 2, wherein the total amount of (a) copper oxide, (b) ruthenium metal or ruthenium oxide and (c) alkaline metal component or alkaline earth metal component is 0.01 to 80% by weight of the amount of the catalyst.

8. The process according to claim 1 or 2, wherein the copper/ruthenium metal molar ratio in the catalyst is 1/99 to 99/1.

9. The process according to claim 1 or 2, wherein the ruthenium/(c) component metal molar ratio in the catalyst is 1/99 to 99/1.

10. The process according to claim 1 or 2, wherein (a) copper oxide is CuO.

11. The process according to claim 1 or 2, wherein (h) ruthenium metal or ruthenium oxide is RuO₂.

12. The process according to claim 1 or 2, wherein the (c) alkaline metal component or alkaline earth metal component is an alkaline metal-containing compound.

13. The process according to claim 1 or 2, wherein (c) alkaline metal component or alkaline earth metal component is a sodium-containing compound.

14. The process according to claim 3, wherein the catalyst is obtained by impregnating a porous support with a solution containing a copper ion, a ruthenium ion and an alkaline metal or alkaline earth metal ion to prepare a composition, followed by calcining the composition.

15. The process according to claim 3 or 4, wherein the catalyst is obtained by impregnating a porous support with a solution containing a copper ion, a ruthenium ion, an alkaline metal or alkaline earth metal ion and a halogen ion to prepare a composition, followed by calcining the composition.

16. The process according to claim 1 or 2, wherein the olefin is propylene and the olefin oxide is propylene oxide.

17. The process according to claim 1 or 2, which comprises reacting an olefin with oxygen at a temperature of 100 to 350° C.

18. A catalyst for production of an olefin oxide which comprises (a) copper oxide, (b) ruthenium metal or ruthenium oxide and (c) alkaline metal component or alkaline earth metal component.

19. The catalyst according to claim 18, which comprises (d) halogen component.

20. The catalyst according to claim 18, wherein (a) copper oxide, (b) ruthenium metal or ruthenium oxide and (c) alkaline metal component or alkaline earth metal component are supported on a porous support.

21. The catalyst according to claim 19, wherein (a) copper oxide, (b) ruthenium metal or ruthenium oxide, (c) alkaline metal component or alkaline earth metal component and (d) halogen component are supported on a porous support.

22. The catalyst according to claim 20 which is obtained by impregnating a porous support with a solution containing a copper ion, a ruthenium ion and an alkaline metal or alkaline earth metal ion to prepare a composition, followed by calcining the composition.

23. The catalyst according to claim 20 or 21 which is obtained by impregnating a porous support with a solution containing a copper ion, a ruthenium ion, an alkaline metal or alkaline earth metal ion and a halogen ion to prepare a composition, followed by calcining the composition.

24. The catalyst according to claim 18 or 19, wherein (c) alkaline metal component or alkaline earth metal component is an alkaline metal-containing compound.

25. The catalyst according to claim 20 or 21, wherein the porous support comprises Al₂O₃, SiO₂, TiO₂or ZrO₂.

26. The catalyst according to claim 20 or 21, wherein the porous support comprises SiO₂.

27. The catalyst according to claim 18 or 19, wherein the olefin oxide is propylene oxide.

28. Use of a catalyst for producing an olefin oxide, said catalyst comprising (a) copper oxide, (b) ruthenium metal or ruthenium oxide and (c) alkaline metal component or alkaline earth metal component.

29. The use of a catalyst according to claim 28, wherein the olefin oxide is propylene oxide.