JP2011183237A - Method of producing carried ruthenium oxide and method of producing chlorine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of producing carried ruthenium oxide with excellent thermal stability and catalyst service life, and a method of stably producing chlorine over a long period by using the carried ruthenium oxide obtained by the method. <P>SOLUTION: There is provided the method of producing carried ruthenium oxide catalyst, wherein a titania carrier is brought into contact with an acidic aqueous solution containing a ruthenium compound and a silica compound, and then fired in an acidic gas atmosphere. Chlorine is produced by using thus produced carried ruthenium oxide as a catalyst, and oxidizing hydrogen chloride with oxygen in the presence of the catalyst. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for producing supported ruthenium oxide in which ruthenium oxide is supported on a carrier. The present invention also relates to a method for producing chlorine by oxidizing hydrogen chloride with oxygen using the supported ruthenium oxide produced by this method as a catalyst.

  The supported ruthenium oxide is useful as a catalyst for producing chlorine by oxidizing hydrogen chloride with oxygen. For example, Patent Documents 1 and 2 disclose that a ruthenium compound is supported on a titanium oxide carrier. , And then a method of carrying a silicon compound such as an alkoxysilane compound or a siloxane compound and then oxidizing, specifically, firing in air is described. Patent Document 3 describes an ethanol solution of a silicon compound. A method has been proposed in which silica is supported on a titanium oxide support by impregnating with titanium oxide and then calcined in air, then a ruthenium compound is supported, and then calcined in air.

JP 2002-292279 A Japanese Patent Laid-Open No. 2004-074073 JP 2008-155199 A

  However, the supported ruthenium oxide obtained by the conventional manufacturing method tends to sinter (sinter) the carrier and the ruthenium oxide supported on the carrier when subjected to a thermal load such as being used for an oxidation reaction for a long time. When such sintering occurs, the catalytic activity decreases, so that the catalyst life is not always satisfactory. Therefore, the object of the present invention is to suppress the sintering, and to support the supported ruthenium oxide excellent in thermal stability and catalyst life, and can reduce the use of organic substances in the production process, and can be produced more simply and stably at a low cost. It is to provide a manufacturing method. Another object of the present invention is to provide a method for producing chlorine stably over a long period of time using the supported ruthenium oxide obtained by this method.

  As a result of intensive studies, the inventor conducted the above-described object in the production of a supported ruthenium oxide catalyst by subjecting the titania support to an acidic aqueous solution containing a ruthenium compound and a silicon compound, followed by firing in an oxidizing gas atmosphere. The present invention has been completed.

  That is, the present invention provides a method for producing supported ruthenium oxide, characterized in that a titania carrier is contact-treated with an acidic aqueous solution containing a ruthenium compound and a silicon compound and then fired in an oxidizing gas atmosphere.

  The present invention also provides a method for producing chlorine by oxidizing hydrogen chloride with oxygen in the presence of the supported ruthenium oxide produced by the above method.

  According to the present invention, supported ruthenium oxide having excellent thermal stability and catalyst life can be stably produced at a low cost, and hydrogen chloride is oxidized with oxygen using the thus-supported ruthenium oxide as a catalyst. Thus, chlorine can be produced.

  Hereinafter, the present invention will be described in detail. The supported ruthenium oxide of the present invention is a supported ruthenium oxide in which ruthenium oxide and silica are supported on a titania carrier. Such titania carrier can be composed of rutile-type titania (titania having a rutile-type crystal structure), anatase-type titania (titania having an anatase-type crystal structure), amorphous titania, etc. You may consist of these mixtures. In the present invention, a titania carrier composed of rutile titania and / or anatase titania is preferable. Among them, the ratio of rutile titania to rutile titania and anatase titania in the titania carrier (hereinafter sometimes referred to as a rutile titania ratio). .) Is preferably 20% or more of a titania carrier, more preferably 30% or more of a titania carrier, and even more preferably 90% or more of a titania carrier. The higher the rutile-type titania ratio, the better the catalytic activity of the resulting supported ruthenium oxide. The rutile-type titania ratio can be measured by an X-ray diffraction method (hereinafter referred to as XRD method) and is represented by the following formula (1).

Rutile titania ratio [%] = _{[I R / (I A + I} R) ] × 100 (1)

I _R : Intensity of diffraction line showing rutile type titania (110) plane I _A : Intensity of diffraction line showing anatase type titania (101) plane

  If the titania carrier contains sodium or calcium, the greater the content thereof, the lower the catalytic activity of the obtained supported ruthenium oxide, so the sodium content is 200 ppm by weight or less. The calcium content is preferably 200 ppm by weight or less. Further, since alkali metals other than sodium and alkaline earth metals other than calcium can adversely affect the catalytic activity of the obtained supported ruthenium oxide, the total alkali metal content is more preferably 200 ppm by weight or less. Moreover, it is more preferable that the content of the total alkaline earth metal is 200 ppm by weight or less. The content of these alkali metals and alkaline earth metals can be measured by, for example, inductively coupled plasma emission spectroscopy (hereinafter sometimes referred to as ICP analysis), atomic absorption analysis, ion chromatography analysis, etc. Preferably, it is measured by ICP analysis. The titania carrier may contain oxides such as alumina, zirconia and niobium oxide.

The specific surface area of the titania carrier can be measured by a nitrogen adsorption method (BET method), and is usually measured by a BET one-point method. The specific surface area obtained by the measurement is usually 5 to 300 m ² / g, preferably 5 to 50 m ² / g. When the specific surface area is too high, titania and ruthenium oxide in the obtained supported ruthenium oxide are easily sintered, and thermal stability may be lowered. On the other hand, if the specific surface area is too low, the ruthenium oxide in the obtained supported ruthenium oxide becomes difficult to disperse and the catalytic activity may be lowered.

  As the titania carrier, it is possible to use a powdered or sol-like titania kneaded and molded and then fired. The titania carrier can be prepared based on a known method. For example, titania powder or titania sol is kneaded with a molding aid such as an organic binder and water, extruded into a noodle shape, dried, crushed, and the like. It can be prepared by obtaining a shaped body and then firing the obtained shaped body in an oxidizing gas atmosphere such as air.

  Examples of the method of supporting the ruthenium oxide and silica on the titania support thus obtained include a method of supporting a ruthenium compound and a silicon compound on the titania support and then firing in an oxidizing gas atmosphere.

As the ruthenium compound, for _example, RuCl 3, such as halides _{RuBr 3, K 3 RuCl 6,} K 2 RuCl such halogeno salt of _6, such as oxo acid salt of _{K 2 RuO 4, Ru 2 OCl} 4, Ru 2 Oxyhalides such as OCl ₅ and Ru ₂ OCl ₆ , K ₂ [RuCl ₅ (H ₂ O) ₄ ], [RuCl ₂ (H ₂ O) ₄ ] Cl, K ₂ [Ru ₂ OCl ₁₀ ], Cs ₂ [ Halogeno complexes such as Ru ₂ OCl ₄ ], [Ru (NH ₃ ) ₅ H ₂ O] Cl ₂ , [Ru (NH 3) ₅ Cl] Cl ₂ , [Ru (NH ₃ ) ₆ ] Cl ₂ , [Ru (NH _{3) 6] Cl 3, [} Ru (NH 3) 6] such ammine complex of _{Br 3, Ru (CO) 5} , Ru 3 (CO) 12 , such as carbonyl _complexes, [Ru 3 O (OCO _{H 3) 6 (H 2 O} ) 3] OCOCH 3, [Ru 2 (OCOR) 4] Cl (R = alkyl group having 1 to 3 carbon atoms) such as carboxylato _{complexes, K 2 [RuCl 5 (NO} )] , [Ru (NH ₃ ) ₅ (NO)] Cl ₃ , [Ru (OH) (NH ₃ ) ₄ (NO)] (NO ₃ ) ₂ , [Ru (NO)] (NO ₃ ) ₃ Phosphine complex, amine complex, acetylacetonato complex, and the like. Of these, halides are preferably used, and chlorides are particularly preferably used. In addition, as a ruthenium compound, the hydrate may be used as needed, and those 2 or more types may be used.

  The use ratio of the ruthenium compound and the titania carrier is such that the weight ratio of the ruthenium oxide / titania carrier in the supported ruthenium oxide obtained after calcination described later is usually 0.1 / 99.9 to 20/80, preferably 0.3 / What is necessary is just to adjust suitably so that it may become 99.7-10 / 85, More preferably, it is 0.5 / 99.5-5 / 95. If there is too little ruthenium oxide, the catalytic activity may not be sufficient, and if it is too much, it will be disadvantageous in cost. In addition, the amount of ruthenium compound used is preferably adjusted so that the ruthenium oxide in the supported ruthenium oxide is 0.1 to 4 mol per mol of silica supported on the titania carrier, and 0.3 to 2 mol. It is more preferable to adjust so that. If the number of moles of ruthenium oxide relative to 1 mole of silica is too high, the thermal stability of the supported ruthenium oxide may be low, and if it is too low, the catalytic activity may be low.

Examples of the silicon compound include silicon alkoxide compounds such as Si (OR) ₄ (hereinafter, R represents an alkyl group having 1 to 4 carbon atoms), silicon chloride (SiCl ₄ ), and silicon bromide (SiBr ₄ ). Examples thereof include silicon halides, silicon halide alkoxide compounds such as SiCl (OR) ₃ , SiCl ₂ (OR) ₂ , SiCl ₃ (OR), and silicon hydroxide compounds. Moreover, the hydrate may be used as needed and 2 or more types thereof may be used. In the present invention, among them, silicon alkoxide compounds are preferable, and silicon tetraethoxide, that is, tetraethyl orthosilicate [Si (OC ₂ H ₅ ) ₄ ] is more preferable. The usage-amount of a silicon compound is 0.001-0.3 mol normally with respect to 1 mol of titania, Preferably it is 0.002-0.15 mol, More preferably, it is 0.004-0.03 mol.

  Examples of the method for supporting the ruthenium compound and the silicon compound on the titania carrier include a method of contacting the titania carrier with an acidic aqueous solution containing the ruthenium compound and the silicon compound. In the contact treatment, the temperature during the treatment is usually 0 to 100 ° C., preferably 0 to 50 ° C., and the pressure during the treatment is usually 0.1 to 1 MPa, preferably atmospheric pressure. Such contact treatment can be performed in an air atmosphere or in an inert gas atmosphere such as nitrogen, helium, argon, oxygen dioxide, and may contain water vapor.

  Examples of the contact treatment include impregnation or immersion. Examples of the method for contact treatment with the acidic aqueous solution include (A) impregnating a titania carrier with an acidic aqueous solution containing a ruthenium compound and a silicon compound, and (B) immersing the titania carrier in an acidic aqueous solution containing a ruthenium compound and a silicon compound. (C) impregnating titania carrier with acidic aqueous solution of silicon compound and then impregnating aqueous solution containing ruthenium compound, (D) immersing titania carrier in acidic aqueous solution of silicon compound and then immersed in aqueous solution containing ruthenium compound (E) impregnating a titania carrier with an acidic aqueous solution of a silicon compound and then immersing it in an aqueous solution containing a ruthenium compound. (F) immersing the titania carrier in an acidic aqueous solution of a silicon compound and then containing an aqueous solution containing a ruthenium compound. (G) containing a ruthenium compound in a titania carrier After impregnating the solution, impregnating an acidic aqueous solution of the silicon compound, (H) immersing the titania carrier in an aqueous solution containing a ruthenium compound, and then immersing it in an acidic aqueous solution of the silicon compound. (I) ruthenium compound in the titania carrier. Impregnation with an aqueous solution containing silicon, soaking in an acidic aqueous solution of silicon compound, (H) soaking the titania carrier in an aqueous solution containing ruthenium compound, and then impregnating with an acidic aqueous solution of silicon compound. However, in the methods (C) to (H), impregnation and / or dipping is performed twice, whereas in the method (A) or (B), only one time is required. It is preferable in terms of In particular, the method (A) is preferred.

  In the acidic aqueous solution, when a silicon alkoxide compound and / or a silicon halide alkoxide compound having low solubility in water is used as the silicon compound, the silicon compound is hydrolyzed and dissolved in the acidic aqueous solution. When using the acidic aqueous solution, it is preferable to use it after the silicon compound is dissolved in the acidic aqueous solution to form a uniform solution. However, when stirring is continued after a uniform solution is obtained, or when the mixture is left for a long time near the mixing temperature, silica insoluble in the acidic aqueous solution may be generated. When the contact treatment with the titania support is performed using such a liquid, there is a problem that a predetermined amount of silica cannot be supported on the titania support, and the silica may be unevenly supported on the support. The thermal stability of the supported ruthenium oxide catalyst becomes insufficient. For this reason, after confirming that the acidic aqueous solution has become a homogeneous solution, it is desirable to immediately stop stirring and use it immediately for the contact treatment. When storing the acidic aqueous solution, it is desirable to store it in an airtight state by cooling it to the extent that it does not freeze.

  The acidic aqueous solution is usually an aqueous solution colored by the presence of a ruthenium compound. Therefore, since it may be difficult to confirm whether the silicon compound is dissolved and the solution is uniform, or whether insoluble silica is not generated in the solution, first, an acidic aqueous solution of the silicon compound is added. It is desirable to dissolve the ruthenium compound after preparing and confirming that it is a one-phase transparent and uniform solution and that insoluble silica is not formed. It is sufficient to confirm that the acidic aqueous solution of the silicon compound is a one-phase transparent and uniform solution by visual inspection. The mixing time until the acidic aqueous solution of the silicon compound becomes a one-phase transparent and uniform solution can be adjusted by the amount of the acid contained in the acidic aqueous solution and the mixing temperature. When the amount of the acid used relative to the silicon compound is too large, or when the mixing temperature is too high, silica that is insoluble in the mixed solution is generated and becomes cloudy, and the desired uniform solution may not be obtained. The mixing temperature is preferably 60 ° C. or lower, and more preferably 40 ° C. or lower, in order to allow the hydrolysis to proceed stably in the appropriate amount of acid described below.

  Examples of the acid contained in the acidic aqueous solution include inorganic acids having one hydrogen ion that can be liberated in one molecule such as hydrogen chloride and nitric acid, and hydrogen that can be liberated in one molecule such as sulfuric acid. Free in one molecule, such as inorganic acid having two ions, phosphoric acid, etc., inorganic acid having three free hydrogen ions in one molecule, methanesulfonic acid, trifluoroacetic acid, etc. The organic acid etc. which have one possible hydrogen ion can be mentioned, and it is necessary to be soluble in water. Further, if the acid remains on the surface of the supported ruthenium oxide catalyst, the activity may be lowered. Therefore, the acid is preferably removed from the catalyst by drying and firing described later. Therefore, it is desirable to use an acid that can be easily removed at that time. For example, an acid having a boiling point lower than the firing temperature at the time of firing described below, which is carried out after a ruthenium compound and a silicon compound are supported on a titania carrier, is used. It is desirable to do. However, even when an acid having a boiling point higher than the calcination temperature is used, there is no problem as long as the acid can be removed by appropriate washing after the calcination, but this is not preferable because the process is increased and complicated. Considering the above points, the acid is most preferably hydrogen chloride.

  As the acid contained in the acidic aqueous solution, it is desirable that the amount used is as small as possible in consideration of the possibility of causing corrosion of the apparatus and the possibility of promoting the generation of silica insoluble in the acidic aqueous solution. However, if the amount used is too small, the performance of the supported ruthenium oxide catalyst is reduced, and the mixing time until the acidic aqueous solution becomes a one-phase transparent and uniform solution becomes very long and the efficiency is lowered. There is. Under the above mixed temperature condition of 40 ° C. or less, the amount of acid contained in the acidic aqueous solution of ruthenium compound and silicon compound is such that hydrogen that can be liberated from the acid with respect to 1 mol of the silicon compound used for the preparation of the aqueous solution. It is preferably 0.0003 to 3.5 mol, more preferably 0.003 to 0.35 mol in terms of ion amount. The amount of hydrogen ions that can be liberated from the acid is represented by the following formula (2).

Amount of hydrogen ion releasable from acid [mol] = Amount of acid used [mol] × number of hydrogen ions releasable from acid [−] × degree of dissociation of acid at mixing temperature [−] (2)

  The water contained in the acidic aqueous solution of the ruthenium compound and silicon compound is preferably water with high purity such as distilled water, ion exchange water, or ultrapure water. If the water used contains a large amount of impurities, such impurities may adhere to the catalyst and reduce the activity of the catalyst. The usage-amount of water is 0.7-5000 mol normally with respect to 1 mol of silicon compounds in the said acidic aqueous solution, Preferably it is 1.5-2500 mol, More preferably, it is 7-1500 mol. Moreover, it is 1.5-8000 mol normally with respect to 1 mol of ruthenium compounds in the said acidic aqueous solution, Preferably it is 3-2500 mol, More preferably, it is 7-1500 mol. The minimum amount of water required to support the ruthenium compound and silicon compound on the titania support is from the total pore volume of the titania support used to the volume of the ruthenium compound, silicon compound and acid contained in the acidic aqueous solution used for the support. The amount excluding.

  Thus, the ruthenium compound and silicon compound can be supported on the titania carrier. In addition, after carrying | supporting a ruthenium compound and a silicon compound, for example in Unexamined-Japanese-Patent No. 2000-229239, Unexamined-Japanese-Patent No. 2000-254502, Unexamined-Japanese-Patent No. 2000-281314, Unexamined-Japanese-Patent No. 2002-79093 etc. Reduction processing may be performed as described.

  A ruthenium compound and a silicon compound are supported on the titania carrier, and then fired in an oxidizing gas atmosphere. By such firing, the supported ruthenium compound and silicon compound are converted into ruthenium oxide and silica. When the supported ruthenium oxide is used as an oxidation reaction catalyst, the silicon compound does not have to be all silica after calcination, and even if a part of the alkoxide group or the hydrolyzed silicon compound remains, the oxidation reaction can be performed. There is no problem because it is converted to silica. The oxidizing gas is a gas containing an oxidizing substance, and examples thereof include an oxygen-containing gas. The oxygen concentration is usually about 1 to 30% by volume. As the oxygen source, air or pure oxygen is usually used, and diluted with an inert gas as necessary. Of these, air is preferable as the oxidizing gas. A calcination temperature is 100-500 degreeC normally, Preferably it is 200-400 degreeC.

  The titania carrier may be supported with a ruthenium compound and a silicon compound, dried, and then fired in an oxidizing gas atmosphere. As the drying method, a conventionally known method can be adopted, and the temperature is usually from room temperature to about 100 ° C., and the pressure is usually from 0.001 to 1 MPa, preferably atmospheric pressure. Such drying can be performed in an air atmosphere or an inert gas atmosphere such as nitrogen, helium, argon, or oxygen dioxide, and may contain water vapor.

By the firing, a supported ruthenium oxide in which ruthenium oxide and silica are supported on a titania carrier can be produced. The ruthenium oxidation number in the supported ruthenium oxide is usually +4, and the ruthenium oxide is ruthenium dioxide (RuO ₂ ), but other ruthenium oxides or other forms of ruthenium oxide are included. Also good.

  In the supported ruthenium oxide produced in the present invention, the coating ratio of the silica supported on the titania support can be expressed as the monomolecular coverage θ of the silica with respect to the specific surface area of the titania support. Indicated.

_{θ = a m × A / S} × 100 (3)
θ: Monomolecular coverage [%]
S: Specific surface area of the titania carrier [m ² / g]
A: Number of silica molecules supported per 1 g of titania support in supported ruthenium oxide in which ruthenium oxide and silica are supported on a titania support [pieces / g]
a _m : molecular occupation area of silica [= 0.139 × 10 ⁻¹⁸ [m ² / piece]]

Incidentally, molecular area a _m of the silica is a value calculated from the following equation (4).
a _m = 1.091 (M _w / (Nd)) ^2/3 (4)
M _w : Molecular weight of silica [= 60.07 [g / mol]]
N: Avogadro number [= 6.02 × 10 ²³ [pieces]]
d: True density of silica [= 2.2 × 10 ⁶ [g / m ³ ]]

  The monomolecular coverage θ is usually 10 to 200%, preferably 10 to 150%, and more preferably 40 to 140%. That is, the amount of silicon compound and the like used is appropriately adjusted when preparing the titania carrier so as to have such a value. When the monomolecular coverage θ is too low, titania or ruthenium oxide in the supported ruthenium oxide obtained after firing is likely to sinter and thermal stability may be lowered. On the other hand, if the monomolecular coverage θ is too high, the ruthenium compound is hardly supported on titania, and the catalytic activity of the obtained supported ruthenium oxide may be lowered.

  The supported ruthenium oxide thus produced is used as a catalyst, and chlorine can be efficiently produced by oxidizing hydrogen chloride with oxygen in the presence of this catalyst. As the reaction method, a reaction method such as a fluidized bed, a fixed bed, or a moving bed can be adopted, and an adiabatic or heat exchange type fixed bed reactor is preferable. When an adiabatic fixed bed reactor is used, either a single tube fixed bed reactor or a multitubular fixed bed reactor can be used, but a single tube fixed bed reactor is preferably used. Can do. When a heat exchange type fixed bed reactor is used, either a single-tube fixed bed reactor or a multi-tube fixed bed reactor can be used, but a multi-tube fixed bed reactor is preferably used. be able to.

This oxidation reaction is an equilibrium reaction, and if it is carried out at a very high temperature, the equilibrium conversion rate is lowered. Therefore, the oxidation reaction is preferably carried out at a relatively low temperature, and the reaction temperature is usually 100 to 500 ° C., preferably 200 to 450 ° C. The reaction pressure is usually about 0.1 to 5 MPa. As the oxygen source, air or pure oxygen may be used. The theoretical molar amount of oxygen with respect to hydrogen chloride is 1/4 mole, but usually 0.1 to 10 times the theoretical amount of oxygen is used. Further, the supply rate of hydrogen chloride is usually about 10 to 20000 h ^{−1 in} terms of gas supply rate per 1 L of catalyst (L / h; 0 ° C., converted to 1 atm), that is, GHSV.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to this embodiment.

  Examples of the present invention will be shown below, but the present invention is not limited thereto.

Example 1
(Preparation of carrier)
100 parts of titania powder [Showa Titanium Co., Ltd. F-1R, rutile type titania ratio 93%] and 2 parts of organic binder [YB-152A made by Yuken Industry Co., Ltd.] were mixed, and then 29 parts of pure water 12.5 parts of titania sol [CSB manufactured by Sakai Chemical Co., Ltd., titania content 40%] was added and kneaded. This mixture was extruded into a noodle shape having a diameter of 3.0 mmφ, dried at 60 ° C. for 2 hours, and then crushed to a length of about 3 to 5 mm. The obtained molded body was heated in air from room temperature to 600 ° C. over 1.7 hours, then held at the same temperature for 3 hours and fired to obtain a white titania carrier (specific surface area: 16 m ² / g). Got.

(Production of supported ruthenium oxide)
In a 50 ml glass sample bottle, put 10.39 g of 0.10 wt% hydrochloric acid and 1.71 g of tetraethyl orthosilicate [Si (OC ₂ H ₅ ) ₄ ] manufactured by Wako Pure Chemical Industries, Ltd.] Stir at room temperature until complete. The time until the solution became uniform was about 2 hours. 4.84 g of the obtained solution was weighed, and 0.486 g of ruthenium chloride hydrate (RuCl ₃ · nH ₂ O manufactured by NE Chemcat Co., Ru content 40.0 wt%) was dissolved therein. 20.00 g of the titania support was impregnated with the obtained solution (hydrogen ion amount releasable from hydrogen chloride / tetraethyl orthosilicate = 0.033 (molar ratio)), and then dried for 2 days at room temperature in an air atmosphere. 21.36 g of a brown solid was obtained. Of the obtained solid, 10.04 g was heated from room temperature to 300 ° C. over 1.3 hours under air flow, then calcined by holding at that temperature for 2 hours, and the silica content was 0.96. 9.67 g of blue-gray-supported ruthenium oxide having a weight% of ruthenium oxide content of 1.25% by weight was obtained.

(Thermal stability test of supported ruthenium oxide)
A quartz reaction tube (21 mm inner diameter) was charged with 1.2 g of the supported ruthenium oxide obtained above. In this, 0.086 mol / h of hydrogen chloride gas (1.9 L / h in terms of 0 ° C. and 1 atm) and 0.075 mol / h of oxygen gas (1.7 L / h in terms of 1 atm at 0 ° C.) ), Chlorine gas at a rate of 0.064 mol / h (1.4 liter / h in terms of 1 atm at 0 ° C.) and water vapor at a rate of 0.064 mol / h (1.4 liter / h in terms of 1 atm at 0 ° C.) The reaction was carried out by supplying under pressure and heating the catalyst layer to 435 to 440 ° C. At 50 hours after the start of the reaction, the reaction was stopped, and cooling was performed while supplying nitrogen gas at a rate of 0.214 mol / h (0 ° C., 4.8 L / h in terms of 1 atm).

(Activity evaluation of supported ruthenium oxide after thermal stability test)
Of 1.2 g of supported ruthenium oxide subjected to the above thermal stability test, 1.0 g was collected and diluted with 12 g of α-alumina sphere having a diameter of 2 mm [SSA995 manufactured by Nikkato Co., Ltd.] The tube (inner diameter 14 mm) was filled, and the same α-alumina sphere 12 g as above was filled as a preheating layer on the gas inlet side of the reaction tube. In this, 0.214 mol / h of hydrogen chloride gas (4.8 L / h in terms of 0 ° C. and 1 atm) and 0.107 mol / h of oxygen gas (2.4 L / h in terms of 0 atm and 1 atm) ) Under normal pressure and the catalyst layer was heated to 282 to 283 ° C. to carry out the reaction. At 1.5 hours after the start of the reaction, sampling was performed for 20 minutes by circulating the gas at the outlet of the reaction tube through a 30% aqueous solution of potassium iodide, the amount of chlorine produced was measured by iodine titration, and the chlorine production rate. (Mol / h) was determined. The conversion rate of hydrogen chloride was calculated from the following formula from the chlorine production rate and the above-mentioned hydrogen chloride supply rate, and is shown in Table 1.

  Hydrogen chloride conversion rate (%) = [chlorine production rate (mol / h) × 2 ÷ hydrogen chloride supply rate (mol / h)] × 100

Example 2
(Preparation of carrier, production of supported ruthenium oxide and its evaluation)
A supported ruthenium oxide was produced in the same manner as in Example 1 except that the drying time after impregnation was 1 day in (Production of supported ruthenium oxide). Drying after impregnation gave 24.42 g of a brown solid. The obtained solid (10.52 g) was heated from room temperature to 300 ° C. over 1.3 hours under air flow, then calcined by holding at the same temperature for 2 hours, and the silica content was 0.96 wt% Thus, 8.96 g of blue-gray-supported ruthenium oxide having a ruthenium oxide content of 1.25% by weight was obtained. The obtained supported ruthenium oxide was subjected to a thermal stability test and an activity evaluation after the test in the same manner as in Example 1. The results are shown in Table 1.

Example 3
(Preparation of carrier, production of supported ruthenium oxide and its evaluation)
In the same manner as in Example 1 except that the temperature was raised from room temperature to 300 ° C. over 1.3 hours in (production of supported ruthenium oxide) over 1.1 hours from room temperature to 250 ° C. Supported ruthenium oxide was produced. The obtained supported ruthenium oxide was subjected to a thermal stability test and an activity evaluation after the test in the same manner as in Example 1. The results are shown in Table 1.

Example 4
(Preparation of carrier, production of supported ruthenium oxide and its evaluation)
In the same manner as in Example 1 except that the temperature was raised from room temperature to 300 ° C. over 1.3 hours in (production of supported ruthenium oxide) over 1.5 hours from room temperature to 350 ° C. Supported ruthenium oxide was produced. The obtained supported ruthenium oxide was subjected to a thermal stability test and an activity evaluation after the test in the same manner as in Example 1. The results are shown in Table 1.

Example 5
(Preparation of carrier, production of supported ruthenium oxide and its evaluation)
A supported ruthenium oxide was produced in the same manner as in Example 1 except that in the production of supported ruthenium oxide, 10.32 g of 0.01 wt% hydrochloric acid was used instead of 10.39 g of 0.10 wt% hydrochloric acid. . The obtained supported ruthenium oxide was subjected to a thermal stability test and an activity evaluation after the test in the same manner as in Example 1. The results are shown in Table 1.

Example 6
(Preparation of carrier, production of supported ruthenium oxide and its evaluation)
A supported ruthenium oxide was prepared in the same manner as in Example 1 except that 10.31 g of 1.0 wt% hydrochloric acid was used instead of 10.39 g of 0.10 wt% hydrochloric acid in (Production of supported ruthenium oxide). . The obtained supported ruthenium oxide was subjected to a thermal stability test and an activity evaluation after the test in the same manner as in Example 1. The results are shown in Table 1.

Example 7
(Preparation of carrier)
A white titania carrier was obtained in the same manner as in Example 1.

(Production of supported ruthenium oxide)
Put 50.25 g of 0.10 wt% hydrochloric acid and 1.77 g of tetraethyl orthosilicate [Si (OC ₂ H ₅ ) ₄ ] manufactured by Wako Pure Chemical Industries, Ltd.) in a 50 ml glass sample bottle. Stir at room temperature until complete. The time until the solution became uniform was about 1 hour. 2.43 g of the obtained solution was weighed, and 0.242 g of ruthenium chloride hydrate (Nu Chemcat Co., Ltd. RuCl ₃ · nH ₂ O, Ru content 40.0 wt%) was dissolved therein to obtain 10.01 g of the titania carrier was impregnated with the obtained solution (hydrogen ion amount releasable from hydrogen chloride / tetraethyl orthosilicate = 0.073 (molar ratio)), and then dried at room temperature for 2 days in an air atmosphere. 10.67 g of a brown solid was obtained. Of the obtained solid, 5.02 g of the solid was heated from room temperature to 250 ° C. over 1.1 hours under air flow, and then calcined by holding at that temperature for 2 hours, so that the silica content was 0.50. 4.83 g of blue-gray-supported ruthenium oxide having a weight% ruthenium oxide content of 1.25% by weight was obtained.

(Evaluation of supported ruthenium oxide)
The obtained supported ruthenium oxide was subjected to a thermal stability test and an activity evaluation after the test in the same manner as in Example 1. The results are shown in Table 1.

Example 8
(Preparation of carrier)
A white titania carrier was obtained in the same manner as in Example 1.

(Production of supported ruthenium oxide)
Into a 30 ml glass sample bottle, 9.78 g of 0.10% by weight hydrochloric acid and 2.23 g of tetraethyl orthosilicate [Si (OC ₂ H ₅ ) ₄ ] manufactured by Wako Pure Chemical Industries, Ltd.) were put into a transparent and uniform solution. Stir at room temperature until complete. The time until the solution became uniform was about 0.5 hours. 2.41 g of the obtained solution was weighed and 0.244 g of ruthenium chloride hydrate (RuCl ₃ · nH ₂ O manufactured by NE Chemcat Co., Ltd., Ru content 40.0 wt%) dissolved therein was obtained. 10.00 g of the titania support was impregnated with the resulting solution (the amount of hydrogen ions that can be liberated from hydrogen chloride / tetraethyl orthosilicate = 0.025 (molar ratio)), and then dried at room temperature for 2 days in an air atmosphere. 10.87 g of a brown solid was obtained. 5.02 g of the obtained solid was heated from room temperature to 250 ° C. over 1.1 hours under air flow, and then calcined by holding at the same temperature for 2 hours, so that the silica content was 1.26. 4.79 g of blue-gray-supported ruthenium oxide having a weight% ruthenium oxide content of 1.25% by weight was obtained.

(Evaluation of supported ruthenium oxide)
The obtained supported ruthenium oxide was subjected to a thermal stability test and an activity evaluation after the test in the same manner as in Example 1. The results are shown in Table 1.

Example 9
(Preparation of carrier)
A white titania carrier was obtained in the same manner as in Example 1.

(Production of supported ruthenium oxide)
Into a 30 ml glass sample bottle, 9.34 g of 0.10 wt% hydrochloric acid and 2.68 g of tetraethyl orthosilicate [Si (OC ₂ H ₅ ) ₄ ] manufactured by Wako Pure Chemical Industries, Ltd.) are placed in a transparent and uniform solution. Stir at room temperature until complete. The time until the solution became uniform was about 0.5 hours. 2.40 g of the obtained solution was weighed, and 0.245 g of ruthenium chloride hydrate (Ne Chemcat Co., Ltd. RuCl ₃ .nH ₂ O, Ru content 40.0 wt%) was dissolved therein. The obtained solution (the amount of hydrogen ions that can be liberated from hydrogen chloride / tetraethyl orthosilicate = 0.020 (molar ratio)) was impregnated in 10.01 g of the titania support, and then dried at room temperature for 2 days in an air atmosphere. 11.06 g of a brown solid was obtained. Of the obtained solid, 5.04 g of the solid was heated from room temperature to 250 ° C. over 1.1 hours under air flow, then held at the same temperature for 2 hours and fired, and the silica content was 1.50. 4.76 g of blue-gray-supported ruthenium oxide having a weight% of ruthenium oxide content of 1.25% by weight was obtained.

(Evaluation of supported ruthenium oxide)
The obtained supported ruthenium oxide was subjected to a thermal stability test and an activity evaluation after the test in the same manner as in Example 1. The results are shown in Table 1.

Example 10
(Preparation of carrier)
A white titania carrier was obtained in the same manner as in Example 1.

(Production of supported ruthenium oxide)
Into a 30 ml glass sample bottle, 9.27 g of 0.10 wt% hydrochloric acid and 1.61 g of tetraethyl orthosilicate [Si (OC ₂ H ₅ ) ₄ ] manufactured by Wako Pure Chemical Industries, Ltd.) are placed in a transparent and uniform solution. Stir at room temperature until complete. The time until the solution became uniform was about 1 hour. 2.42 g of the obtained solution was weighed, and 0.392 g of ruthenium chloride hydrate (RuCl ₃ · nH ₂ O manufactured by NE Chemcat Co., Ltd., Ru content 40.0 wt%) was dissolved therein. 10.01 g of the titania support was impregnated with the obtained solution (hydrogen ion amount releasable from hydrogen chloride / tetraethyl orthosilicate = 0.033 (molar ratio)), and then dried for 2 days at room temperature in an air atmosphere. 10.94 g of a brown solid was obtained. 5.01 g of the obtained solid was heated from room temperature to 250 ° C. over 1.1 hours under air flow, then held at the same temperature for 2 hours and calcined, and the silica content was 1.00. 4.87 g of blue-gray-supported ruthenium oxide having a weight% of ruthenium oxide content of 2.0% by weight was obtained.
(Evaluation of supported ruthenium oxide)
The obtained supported ruthenium oxide was subjected to a thermal stability test and an activity evaluation after the test in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 1
(Preparation of carrier)
A white titania carrier was obtained in the same manner as in Example 1.

(Production of supported ruthenium oxide)
A solution prepared by dissolving 0.357 g of tetraethyl orthosilicate [Si (OC ₂ H ₅ ) ₄ ] manufactured by Wako Pure Chemical Industries, Ltd.) in 1.65 g of ethanol in 10.00 g of the titania carrier obtained above. Impregnation and drying for 1 day at room temperature under air atmosphere. The obtained solid (10.08 g) was heated from room temperature to 300 ° C. over 1.3 hours under air flow, then calcined by holding at the same temperature for 2 hours, and the silica content was 1.02% by weight. As a result, 10.05 g of white silica-supported titania was obtained. In the obtained silica-supported titania, 0.243 g of ruthenium chloride hydrate (Ne Chemcat Co., Ltd. RuCl ₃ · nH ₂ O, Ru content 40.0 wt%) was dissolved in 2.25 g of pure water. The prepared aqueous solution was impregnated and dried at 24 ° C. for 1 day in an air atmosphere. The obtained solid (10.53 g) was heated from room temperature to 250 ° C. over 1.3 hours under air flow, then calcined by holding at the same temperature for 2 hours, and the silica content was 1.01 wt% Thus, 10.14 g of blue-gray-supported ruthenium oxide having a ruthenium oxide content of 1.25% by weight was obtained.

(Evaluation of supported ruthenium oxide)
The obtained supported ruthenium oxide was subjected to a thermal stability test and an activity evaluation after the test in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 2
(Preparation of carrier)
A white titania carrier was obtained in the same manner as in Example 1.

(Production of supported ruthenium oxide)
0.487 g of ruthenium chloride hydrate (Ne Chemcat Co., Ltd. RuCl ₃ · nH ₂ O, Ru content 40.0 wt%) was added to 20.01 g of the titania carrier obtained above. An aqueous solution prepared by dissolving in water was impregnated and dried in an air atmosphere at room temperature for 2 days. In the obtained solid, 10.02 g was heated from room temperature to 250 ° C. over 1.1 hours under air flow, and then calcined by holding at the same temperature for 2 hours, so that the content of ruthenium oxide was 1. As a result, 9.83 g of a blue-gray ruthenium oxide-supporting titania of 27% by weight was obtained. The obtained ruthenium oxide-supporting titania was impregnated with a solution prepared by dissolving 0.355 g of tetraethyl orthosilicate [Si (OC ₂ H ₅ ) ₄ ] manufactured by Wako Pure Chemical Industries, Ltd. in 1.62 g of ethanol, The film was dried at room temperature for 1 day in an air atmosphere. The obtained solid was heated from room temperature to 300 ° C. over 1.3 hours under air flow, then held at the same temperature for 2 hours and calcined, and the silica content was 1.00% by weight, ruthenium oxide As a result, 9.50 g of blue-gray-supported ruthenium oxide having a content of 1.25% by weight was obtained.

(Evaluation of supported ruthenium oxide)
The obtained supported ruthenium oxide was subjected to a thermal stability test and an activity evaluation after the test in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 3
(Preparation of carrier)
A white titania carrier was obtained in the same manner as in Example 1.

(Production of supported ruthenium oxide)
To 10.00 g of the titania carrier titania carrier obtained above, 0.243 g of ruthenium chloride hydrate [Nu Chemcat Co., Ltd. RuCl ₃ · nH ₂ O, Ru content 40.0 wt%] and tetraethyl orthosilicate [Si (OC ₂ H ₅ ) ₄ manufactured by Wako Pure Chemical Industries, Ltd.] impregnated with a solution prepared by dissolving 0.360 g in 1.62 g of ethanol, dried at room temperature for 2 days in an air atmosphere, 10 .54 g of a brown solid was obtained. 2.51 g of the obtained solid was heated from room temperature to 250 ° C. over 1.1 hours under air flow, and then calcined by holding at the same temperature for 2 hours, so that the silica content was 1.01. There were obtained 2.47 g of blue-gray-supported ruthenium oxide having a weight% ruthenium oxide content of 1.25% by weight.

(Evaluation of supported ruthenium oxide)
The obtained supported ruthenium oxide was subjected to a thermal stability test and an activity evaluation after the test in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 4
(Preparation of carrier, production of supported ruthenium oxide and its evaluation)
In the same manner as in Comparative Example 3, except that the temperature was raised from room temperature to 250 ° C. over 1.1 hours in (production of supported ruthenium oxide) over 1.3 hours from room temperature to 300 ° C. Supported ruthenium oxide was produced. The obtained supported ruthenium oxide was subjected to a thermal stability test and an activity evaluation after the test in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 5
(Preparation of carrier, production of supported ruthenium oxide and its evaluation)
In the same manner as in Comparative Example 3, except that the temperature was raised from room temperature to 250 ° C. over 1.1 hours in (production of supported ruthenium oxide) over 1.5 hours from room temperature to 350 ° C. Supported ruthenium oxide was produced. The obtained supported ruthenium oxide was subjected to a thermal stability test and an activity evaluation after the test in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 6
(Preparation of carrier)
A white titania carrier was obtained in the same manner as in Example 1.

(Production of supported ruthenium oxide)
2.17 g of 0.10 wt% hydrochloric acid is put into a 50 ml glass sample bottle, and ruthenium chloride hydrate (RuCl ₃ · nH ₂ O manufactured by NE Chemcat Co., Ltd., Ru content 40.0 wt%) is added thereto. 0.240 g was dissolved, and the obtained solution was impregnated in 10.1 g of the titania carrier, and then dried for 2 days at room temperature in an air atmosphere to obtain 10.22 g of a brown solid. 5.00 g of the obtained solid was heated from room temperature to 250 ° C. over 1.1 hours under air flow, and then calcined by holding at the same temperature for 2 hours, whereby the ruthenium oxide content was 1. This gave 4.87 g of blue-gray-supported ruthenium oxide which was 25% by weight.

(Evaluation of supported ruthenium oxide)
The obtained supported ruthenium oxide was subjected to a thermal stability test and an activity evaluation after the test in the same manner as in Example 1. The results are shown in Table 1.

TEOS: Tetraethyl orthosilicate

Claims (8)

  A method for producing a supported ruthenium oxide in which ruthenium oxide and silica are supported on a titania support, wherein the titania support is subjected to a contact treatment with an acidic aqueous solution containing a ruthenium compound and a silicon compound and then fired in an oxidizing gas atmosphere. A method for producing a supported ruthenium oxide.   The amount of the acid contained in the acidic aqueous solution is 0.0003 to 3.5 mol in terms of the amount of hydrogen ions that can be liberated from the acid with respect to 1 mol of the silicon compound. Method for producing supported ruthenium oxide.   The method for producing supported ruthenium oxide according to claim 1 or 2, wherein firing is performed at a temperature of 200 to 400 ° C which is equal to or higher than a boiling point of the acid contained in the acidic aqueous solution.   The method for producing supported ruthenium oxide according to any one of claims 1 to 3, wherein the acid contained in the acidic aqueous solution is hydrogen chloride.   The method for producing supported ruthenium oxide according to any one of claims 1 to 4, wherein the silicon compound is a silicon alkoxide compound.   6. The method for producing supported ruthenium oxide according to claim 5, wherein the silicon alkoxide compound is tetraethyl orthosilicate.   The method for producing supported ruthenium oxide according to any one of claims 1 to 6, wherein a monomolecular coverage of silica in the supported ruthenium oxide is 10 to 150% with respect to a specific surface area of the titania support.   A method for producing chlorine, comprising oxidizing hydrogen chloride with oxygen in the presence of the supported ruthenium oxide produced by the method according to claim 1.