JPH0857323A - Catalyst for decomposition of volatile organic halogen compound and production thereof - Google Patents

Abstract

PURPOSE: To produce a catalyst capable of efficiently decomposing a volatile org. halogen compd. in the presence of air and water and capable of maintaining its activity over a long period of time. CONSTITUTION: At least one kind of metal selected from among Pt, Pd and Ru as a catalytic component is carried on the surface of titania as a carrier by 0.1-2wt.% and a small amt. of phosphorus is incorporated into the resultant catalyst to produce the objective catalyst for decomposition of a volatile org. halogen compd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst for decomposing volatile organic halogen compounds, and more specifically, to a catalyst for catalytically decomposing volatile organic halogen compounds with high decomposition efficiency and durability. And a method for producing the same.

[0002]

2. Description of the Related Art Examples of volatile organic halogen compounds include CFC gas, trichloroethylene, tetrachloroethylene and the like.

Freon gas is widely used not only in the industrial world but also for general consumption because of its excellent chemical properties, especially as propellant and refrigerant. But,
When the CFC gas is discharged into the atmosphere, it finally reaches the ozone layer, and the destruction of the ozone layer by fluorine atoms generated by being decomposed by ultraviolet rays in sunlight becomes a serious problem from the viewpoint of global environment protection. Therefore, when the CFC gas is discharged into the atmosphere, it cannot be discharged as it is, and it is necessary to perform some detoxification treatment.

Trichloroethylene and tetrachloroethylene are chlorine compounds widely used in the degreasing process and the dry cleaning process in metal working. However, since it was found that the chlorine compound has a carcinogenic effect, it has become a problem that it is discharged into the atmosphere, or land and ground water is polluted by landfill or illegal dumping.

In recent years, particularly with respect to the discharge of these volatile organic halogen compounds, strict regulations have come to be enforced in various places from the viewpoint of environmental hygiene, and the volatile organic halogen compounds and waste liquids containing them, etc. Strict control is demanded, and development of these detoxification treatment techniques is strongly demanded at present.

Conventionally, as a method of recovering volatile organic halogen compounds such as CFCs, trichloroethylene and tetrachloroethylene, a method of adsorbing and recovering with volatile organic halogen compounds such as activated carbon and zeolite has been known. Sufficient consideration was not given to the treatment method to render it harmless.

Recently, a high-pressure thermal decomposition method in which a volatile organic halogen compound is burned under high pressure at a temperature of 800 ° C. or higher, a photolytic method in which a volatile organic halogen compound is photolyzed by irradiating ultraviolet rays, and the presence of a catalyst Although catalytic cracking methods such as decomposition are proposed below, the high-pressure thermal decomposition method and photolysis method have problems such as large equipment and high processing cost. Has attracted attention because it can be decomposed and rendered harmless at low cost.

In this catalytic cracking method, a carrier obtained by independently or in combination with inorganic oxides such as alumina, silica, zeolite, titania, zirconia, copper, chromium,
A method of using a catalyst obtained by supporting iron, platinum, palladium or the like as a catalyst component, and contacting this with a volatile organic halogen compound such as trichlorethylene at 400 to 500 ° C. in the presence of water vapor and oxygen or air. It has been adopted and is disclosed in Japanese Patent Laid-Open Nos. 50-2669 and 3-1.
No. 2,221, JP-A-3-47526 and the like are disclosed.

[0009]

Generally, in the catalytic reaction of gas using a catalyst, the reaction should be carried out under conditions of high SV (gas flow rate per unit time / catalyst volume) and fast LV (linear velocity). Is required. For this purpose, it is desirable that the catalyst used in the reaction has a high solid acidity and a large number of active sites, and that a catalyst for decomposing a volatile organic halogen compound has particularly excellent acid resistance to hydrogen halide. is important. From these points, when observing the above-mentioned catalyst, titania,
Zirconia carriers are excellent, but a catalyst in which only a catalyst component such as platinum or palladium is supported on the carrier has a problem that the initial activity of the catalyst is high but the activity cannot be maintained for a long period of time. It was

The present invention has been made in view of the above circumstances, and is capable of efficiently decomposing a volatile organic halogen compound in the presence of air and water and maintaining the activity for a long period of time. Another object of the present invention is to provide a catalyst for decomposing a volatile organic halogen compound and a method for producing the same.

[0011]

In order to achieve the above object, the present invention uses titania as a carrier, and at least one selected from the metal group consisting of platinum, palladium and ruthenium as a catalyst supporting component is used as a carrier. A catalyst for decomposing a volatile organic halogen compound, which comprises a catalyst supported by a supported amount of 1 to 2% by weight and further containing a small amount of phosphorus, and a method for producing the same. In the present invention, phosphorus to be contained in the catalyst may be contained in the carrier together with titania as one of the carrier components, and as one of the catalyst components, a catalyst component such as platinum, palladium or rhodium which is the main catalyst component. It may be supported together with the carrier.

In the present invention, to prepare a titania carrier containing phosphorus, a predetermined amount of phosphoric acid is added to a titania hydrate cake obtained by hydrolyzing a titanium salt,
It may be kneaded and plasticized, molded and fired according to a predetermined formulation. Then, thereafter, a catalyst containing phosphorus can be obtained by supporting the catalyst component metal by a conventional method. Further, in order to obtain a catalyst containing phosphorus as a catalyst component, both may be supported on the carrier by impregnating a titania carrier with a mixed solution containing a predetermined amount of a metal salt of a predetermined catalyst component and a predetermined amount of phosphoric acid, respectively. .

In any case, when the catalyst component is supported, the carrier is previously treated with an alkali so that the catalyst component is supported near the outer surface of the carrier, so that the decomposition activity and The sustainability can be further improved.

[0014]

The details of the present invention and the operation thereof will be described below.

In the structure of the catalyst of the present invention, titania is used as a catalyst carrier, and platinum, palladium or the like is supported as a catalyst component on the catalyst carrier to obtain a catalyst having a decomposition activity for volatile organic halogen compounds. Is already well known about.

The essence of the present invention is that when a catalyst containing titania as a carrier on which a catalyst component such as platinum or palladium is carried and a small amount of phosphorus is further contained, the catalyst It has been found that the catalytic activity effect on the decomposition of the volatile organic halogen compound is dramatically improved and the effect is persistent.

As described above, the catalyst of the present invention is capable of decomposing volatile organic halogen compounds extremely efficiently and continuously because the solid acidity is high due to the inclusion of phosphorus in the catalyst. , Hydrogen molecules are adsorbed at the acidic points of the solid acid, and the Bronsted acid type activity is exhibited.
It is considered that this is because the function of extracting halogen from the volatile halogenated organic compound and decomposing it becomes active on the catalyst surface.

In the catalyst of the present invention, phosphorus to be contained in the catalyst may be contained in the titania carrier as a carrier component, or may be supported on the titania carrier together with the catalyst main component such as platinum and palladium as a catalyst auxiliary component. Good. When phosphorus is included as a carrier component, the phosphorus content is appropriately 1 to 5% by weight in terms of oxide, and when it is included as a catalyst auxiliary component, it is appropriate to be 1 to 3% by weight in terms of oxide. is there.

To prepare a catalyst containing phosphorus as a carrier component, the titania hydrate produced by hydrolysis of the titanium salt is washed to obtain a titania hydrate cake, and the titania hydrate cake is phosphoric acid-containing. Is added, kneaded until sufficiently plasticized, shaped, dried, and further calcined to obtain a phosphorus-containing titania carrier, which can be obtained with a sodium hydroxide solution, aqueous ammonia, or the like. After the alkali treatment, the catalyst active ingredient is supported on the outer surface of the carrier by immersing it in a salt solution of the catalyst active ingredient, that is, a salt solution of platinum salt, palladium salt, ruthenium or the like.

In order to prepare a catalyst containing phosphorus as a catalyst auxiliary component rather than as a carrier component, the above-mentioned carrier preparation method is carried out in the same manner as the above-mentioned carrier preparation method except that phosphoric acid is not added. After obtaining a titania carrier and subjecting it to alkali treatment, it is immersed in a mixed solution of a salt solution and a phosphate solution of the above catalytically active component, so that the catalytically active component and phosphorus are simultaneously supported on the outer surface of the titania carrier. Can be made.

In the present invention, the titanium salt solution used for preparing the carrier is preferably a solution of titanium sulfate, titanium trichloride, titanium tetrachloride, titanium isoprocoxide, or the like, which is used for hydrolysis. The basic solution to be used can be selected from aqueous ammonia, sodium hydroxide solution, ammonium carbonate solution and the like.

The firing temperature of the titania carrier or the phosphorus-containing titania carrier is preferably in the range of 500 to 600 ° C. When the firing temperature is higher than the upper limit, the crystal structure of titanium, which constitutes the main component of the carrier, changes from anatase type to rutile type and the specific surface area of the carrier is reduced, which is not preferable. Further, the shape of the carrier may be a general carrier shape, that is, a cylindrical shape, a spherical shape, a honeycomb shape, or the like which is suitable for the catalytic reaction.

In the present invention, the catalytically active components such as platinum, palladium, ruthenium, etc. are essential active components for decomposing the volatile organic halogen compound, but the supported amount thereof is 0.1 in terms of metal. It is suitable to be 2% by weight. If the supported amount of the active ingredient is less than this range, sufficient decomposing activity is not exhibited, and even if it is more than this range, the effect of further improving the activity cannot be obtained. The need to and is not recognized.

Phosphorus is 1 to 5% by weight as phosphoric acid when contained in the carrier, and 1 to 3% by weight when contained as a supporting component. This is because the effect of promoting the decomposition activity cannot be obtained stably outside the range of this content. The reason for increasing the content when phosphorus is contained in the carrier is that when phosphorus is contained as a carrier component, the phosphorus content is deeper in the catalyst, so that the catalyst is contained more than when it is contained as a catalyst component. This is due to the physical reason that the amount of phosphorus contributing to the increase of active sites on the surface is relatively small.

In any case, it is essential that the carrier is subjected to an alkali treatment before the catalyst component is supported on the carrier, and the effect of the present invention is obtained when the alkali treatment is not carried out. Can't get enough. This is because the catalyst component is supported on the outer surface of the carrier by the alkali treatment, so that many active sites are formed.Also, even when phosphorus is supported, a small amount of support promotes the improvement of the acidity of the catalyst. This is because that.

[0026]

EXAMPLES Examples of the present invention will be described below together with comparative examples.

A. Include phosphorus as a carrier component in the catalyst
Example in the case of preparation [Preparation of carrier] Example 1 45 liters of water was placed in a stainless steel reaction tank with an internal volume of 100 liters equipped with a stirrer, heated to 70 ° C, and kept at the same temperature. Next, 190 g of 14% concentration aqueous ammonia was added to adjust the pH to 9.5, and then 20 kg of an aqueous titanium sulfate solution (2400 g of TiO ₂ ) was added.
PH of 18.2 kg of 14% ammonia water
While maintaining at 9.0 to 9.5, the whole amount was dropped at the same time in 15 minutes, and further aged for 30 minutes to obtain a titania hydrate slurry having a concentration of 2.85 wt% as TiO ₂ . The resulting slurry is filtered to obtain 80
The operation of redispersing the titania hydrate cake in liters and filtering was repeated 3 times to obtain a titania hydrate cake from which sulfate and ammonium sulfate components were removed.

Next, 3.0 kg of the titania hydrate cake (420 g of TiO ₂ ) and 13.9 g of reagent primary phosphoric acid (8.57 g of P ₂ O ₅ ),
As an organic molding aid, 15 g of Avicel (trade name) manufactured by Asahi Kasei Kogyo Co., Ltd. and 5 g of metrose (trade name) manufactured by Shin-Etsu Chemical Co., Ltd. were added and fully plasticized in a kneader with a heating jacket. I kneaded until I did. The loss on ignition of the kneaded product at this time was 55%. Then, the kneaded product was granulated with a granulator into beads having a diameter of 2.0 mm,
After drying at a temperature of 100 ° C. for 15 hours, it was baked at 500 ° C. for 2 hours to obtain a phosphorus-containing titania carrier.

[Preparation of catalyst] Example 2 200 g of the phosphorus-containing titania carrier obtained in Example 1 was impregnated with 60 ml of 14% -concentrated aqueous ammonia and subjected to an alkali treatment for drying the surface, followed by chlorination. A solution of 2.11 grams of platinic acid in 40 liters of water is impregnated and dried at 110 ° C. for 15 hours, then 500
The catalyst A was obtained by calcining at 2 ° C. for 2 hours.

Table 1 shows the loading amount and loading state of platinum in the obtained catalyst A. Regarding the carrying state,
The measurement was performed using an EPMA-2300 type X-ray microanalyzer manufactured by Shimadzu Corporation. Example 3 200 g of each of the phosphorus-containing titania carriers obtained in Example 1 was impregnated with 60 ml of ammonia water having a concentration of 14% and subjected to an alkali treatment for drying the surface, followed by chloroplatinic acid 0.84. Grams and 4.25 grams were each impregnated with a solution in water, dried at 110 ° C. for 15 hours, and then calcined at 500 ° C. for 2 hours to obtain catalyst B and catalyst C.

Table 1 shows the amounts of platinum loaded and the loading states of the obtained catalysts B and C, respectively. Comparative Example 1 In Example 1, the amount of the reagent primary phosphoric acid added to 3.0 g of the titania hydrate cake (420 g as TiO ₂ ) was 3.4 g (2.1 as P ₂ O _5).
1 gram) and 51.3 grams (3 as P ₂ O ₅
The same procedure as in Example 1 was repeated except that the amount of the phosphorus-containing titania carrier was changed to 1.61 g).
With respect to the seed simple substance, platinum was supported by the same procedure as in Example 2 to obtain catalyst D and catalyst E.

Table 1 shows the amount of platinum loaded and the loading state of the obtained catalysts D and E, respectively. Example 4 In Example 1, the addition amount of the reagent primary phosphoric acid added to 3.0 g of the titania hydrate cake (420 g as TiO ₂ ) was 6.9 g (4.2 as P ₂ O _5).
4 grams) and 35.9 grams ( ₂ as P ₂ O ₅
2 kinds of phosphorus-containing titania carriers were obtained by the same procedure as in Example 1 except that the amount was changed to 2.11 g).
Regarding the simple substance of the seed, platinum was supported by the same procedure as in Example 2 to obtain catalyst F and catalyst G.

Table 1 shows the amounts of platinum loaded and the loading states of the obtained catalysts F and G, respectively. Comparative Example 2 200 g of the phosphorus-containing titania carrier obtained in Example 1 was treated with 0.8% of reagent primary chloroplatinic acid without alkali treatment.
A catalyst H was obtained by the same procedure as in Example 2 except that a solution of 4 g dissolved in 60 ml of water was impregnated.

Table 1 shows the loading amount and loading state of platinum in the obtained catalyst H. Comparative Example 3 A titania carrier was obtained by the same procedure as in Example 1 except that phosphoric acid was not added to the titania hydrate cake, and 200 g of the titania carrier was charged with reagent primary chloroplatinic acid 4. A solution of 25 grams dissolved in 60 grams of water was impregnated, dried at 110 ° C. for 15 hours, and then calcined at 500 ° C. for 2 hours to obtain catalyst I.

Table 1 shows the amount and state of platinum supported on the obtained catalyst I.

[Evaluation of catalyst performance] A fixed bed flow type reactor having a catalyst loading of 50 ml was filled with each of the catalysts A to I obtained in the above Examples 2 to 4 and Comparative Examples 1 to 3. A gas sample having the composition shown below at a reaction temperature of 500 ° C. was passed through the catalyst packed bed at SV = 5,000 hr ⁻¹ to decompose trichlorethylene. Table 1 also shows the performance evaluation results of each catalyst after 50 hours from the start of the reaction and after 300 hours from the start of the reaction.

The analysis of the treated gas was carried out using a gas chromatograph manufactured by Shimadzu Corporation.

Gas sample composition Trichlorethylene: 0.23 ml / min Water: 0.33 ml / min Air: 3704.2 ml / min

[0039]

[Table 1] ──────────────────────────────────── Catalyst component in catalyst carrier Trichlorethylene decomposition rate Implementation Symbol P ₂ O ₅ ──────── (%) Number (wt%) Pt supported state ──────────── (wt%) After 50 hours After 300 hours ──── ──────────────────────────────── A 2.0 0.5 Outer surface to 100 μ 99.96 99.95 Example 2 ───── ─────────────────────────────── B 2.0 0.2 Outer surface to 100 μ 99.90 99.90 Example 3 ────── ────────────────────────────── C 2.0 1.0 Outer surface to 100 μ 99.99 99.98 Example 3 ──────── ───────────────────────────── D 0.5 0.5 Outer surface to 100 μ 99.90 96.93 Comparative example 1 ──────────────────────────────────── E 7.0 0.5 Outer surface to 100 μ 99.91 97.12 Comparative Example 1 ──────────────────────────────────── F 1.0 0.5 Outer surface to 100 μ 99.94 99.94 Example 4 ──────────────────────────────────── G 5.0 0.5 Outer surface to 100 μ 99.95 99.95 Example 5 ──────────────────────────────────── H 2.0 0.2 Uniform to the inside 98.53 98.51 Comparative Example 2 ──────────────────────────────────── I-1.0 Uniform inside 99.90 96.23 Comparative example 3 ─── ───────────────────────────────── From the results of Table 1, The catalysts A, B, C, F and G according to Examples 2, 3 and 4 are catalysts in which the content of phosphorus in the titania carrier, the supported amount of the catalyst component and the supported state are within the scope of the present invention. It can be seen that the use of the catalyst according to the invention makes it possible to efficiently decompose trichlorethylene for a long time.

On the other hand, the catalysts D and E according to Comparative Example 1 had a phosphorus content in the titania carrier outside the range of the present invention, and although these catalysts had a considerably high initial performance, they were found to be over a long period of time. The catalyst activity is deteriorated and the decomposition efficiency of trichlorethylene is reduced. From this, the content of phosphorus in the catalyst carrier can contribute to the maintenance of the continuous catalytic activity by increasing the solid acidity of the catalyst within the proper range, that is, the range of the present invention. However, it is understood that such an effect disappears when the content is outside the range of the present invention.

Further, the catalyst H according to Comparative Example 2 is one in which phosphorus is contained in the titania carrier within the content range of the present invention, but since the catalyst component platinum is evenly supported inside the catalyst, It can be seen that although the activity does not change over a long period of time, the decomposition efficiency of trichlorethylene is low from the initial point.

Further, the catalyst I according to Comparative Example 3 is a conventional catalyst in which the titania carrier does not contain phosphorus and the catalyst component is uniformly supported between the insides of the carrier, but the platinum loading amount is increased. Nevertheless, it can be seen that the initial performance is low and the long-term performance is significantly reduced as compared with the catalyst C of the present invention containing the same amount of platinum.

B. Contains phosphorus as a catalyst component in the catalyst
Example for Preparation [Preparation of Carrier] Example 5 45 liters of water was placed in a stainless steel reaction tank having an internal volume of 100 liters equipped with a stirrer, heated to 70 ° C., and kept at the same temperature. Next, 190 g of 14% concentration aqueous ammonia was added to adjust the pH to 9.5, and then 20 kg of an aqueous titanium sulfate solution (2400 g of TiO ₂ ) was added.
PH of 18.2 kg of 14% ammonia water
While maintaining at 9.0 to 9.5, the whole amount was dropped at the same time in 15 minutes, and further aged for 30 minutes to obtain a titania hydrate slurry having a concentration of 2.85 wt% as TiO ₂ . The resulting slurry is filtered to obtain 80
The operation of redispersing the titania hydrate cake in liters and filtering was repeated 3 times to obtain a titania hydrate cake from which sulfate and ammonium sulfate components were removed.

Next, 9.0 kg of titania hydrate cake (1260 g of TiO ₂ ) and Avicel (trade name) 45 manufactured by Asahi Kasei Kogyo Co., Ltd. as an organic molding aid.
Gram and Metrose (trade name) manufactured by Shin-Etsu Chemical Co., Ltd. 1
5 g was added and kneaded in a kneader with a warm jacket until fully plasticized. The loss on ignition of the kneaded product at this time was 55%. Next, the kneaded product was granulated with a granulator into beads having a diameter of 2.0 μm, dried at a temperature of 100 ° C. for 15 hours, and then calcined at 500 ° C. for 2 hours to obtain a phosphorus-containing titania carrier. . The specific surface area of the obtained carrier was determined by the BET method using nitrogen gas adsorption to be 108.
It was square meters / gram.

[Catalyst Preparation] Example 6 200 g of the titania carrier obtained in Example 5 was impregnated with 65 ml of 14% concentration aqueous ammonia, and the surface was dried. After alkali treatment, chloroplatinic acid was added. A solution prepared by dissolving 2.13 g of water in 30 ml of water was impregnated with a mixed solution of 3.3 g of phosphoric acid.
It was dried at 0 ° C. for 15 hours and then calcined at 500 ° C. for 2 hours to obtain catalyst J. 2.18 grams of chloroplatinic acid,
Catalyst K was obtained by the same procedure as above except that the phosphoric acid was changed to 10.1 g.

Table 2 shows the loading amounts and loading states of platinum and phosphorus on the obtained catalysts J and K. The loading state is EPMA-2300 manufactured by Shimadzu Corporation.
The measurement was performed using a type X-ray microanalyzer. Comparative Example 4 200 g of each of the titania carriers obtained in Example 5 was impregnated with 65 ml of 14% concentration aqueous ammonia,
After the alkali treatment for drying the surface, 2.12 g of chloroplatinic acid was dissolved in 30 ml of water and impregnated with a mixed solution of 1.64 g of phosphoric acid,
It was dried at 110 ° C. for 15 hours and then calcined at 500 ° C. for 2 hours to obtain a catalyst L. Further, a catalyst M was obtained by the same procedure as above except that the amount of chloroplatinic acid was changed to 2.22 g and the amount of phosphoric acid was changed to 17.18 g.

Table 2 shows the loading amounts and loading states of platinum and phosphorus in the obtained catalysts L and M, respectively. Example 7 200 g of each of the titania carriers obtained in Example 5 was impregnated with 65 ml of 14% ammonia water,
After performing an alkali treatment for drying the surface, impregnate a mixed solution of 3.33 g of phosphoric acid in a solution of 0.85 g of chloroplatinic acid dissolved in 30 ml of water,
It was dried at 110 ° C. for 15 hours and then calcined at 500 ° C. for 2 hours to obtain catalyst N. Further, a catalyst O was obtained by the same procedure as above except that the chloroplatinic acid was changed to 4.34 g and the phosphoric acid was changed to 3.31 g.

Table 2 shows the loading amounts and loading states of platinum and phosphorus in the obtained catalyst N and catalyst O, respectively. Comparative Example 5 200 g of the titania carrier obtained in Example 5 was dissolved in a solution of 2.13 g of chloroplatinic acid in 65 ml of water without alkali treatment, and 3.3 g of phosphoric acid was added to the mixed solution. Impregnate and dry at 110 ° C for 15 hours,
Then, it was calcined at 500 ° C. for 2 hours to obtain a catalyst P.

Table 2 shows the loading amounts and loading states of platinum and phosphorus in the resulting catalyst P. Comparative Example 6 200 g of the titania carrier obtained in Example 5 was impregnated with a solution of 4.25 g of chloroplatinic acid dissolved in 70 ml of water without alkali treatment, and the temperature was raised at 110 ° C. for 15 hours.
It was dried for an hour and then calcined at 500 ° C. for 2 hours to obtain a catalyst Q.

Table 2 shows the loading amounts and loading states of platinum and phosphorus in the resulting catalyst Q.

[Evaluation of catalyst performance] A fixed bed flow type reactor having a catalyst loading of 50 ml was filled with each of the catalysts J to Q obtained in Examples 5 and 6 and Comparative Examples 4 to 6, A gas sample having the composition shown below at a reaction temperature of 500 ° C. was passed through the catalyst packed bed at SV = 5,000 hr ⁻¹ to decompose trichlorethylene. Table 2 also shows the performance evaluation results of each catalyst after 50 hours from the start of the reaction and after 300 hours from the start of the reaction.

The analysis of the treated gas was carried out using a gas chromatograph manufactured by Shimadzu Corporation.

Gas sample composition Trichlorethylene: 0.23 ml / min Water: 0.33 ml / min Air: 3704.2 ml / min

[0054]

[Table 2] ──────────────────────────────────── Catalyst Catalyst component Catalyst component Trichloroethylene decomposition rate Implementation symbol P ₂ O ₅ Pt supported state (%) Number (wt%) (wt%) ──────────── 50 hours later 300 hours later ───────────── ─────────────────────── J 1.0 0.5 outer surface to 100 μ 99.96 99.96 Example 6 ─────────────── ────────────────────── K 3.0 0.5 outer surface to 100 μ 99.96 99.96 Example 6 ─────────────── ───────────────────── L 0.5 0.5 Outer surface to 100 μ 99.91 99.22 Comparative Example 4 ──────────────── ──────────────────── M 5.0 0.5 Outer surface to 100 μ 99.90 97.80 Comparative example ──────────────────────────────────── N 1.0 0.2 Outer surface to 100 μ 99.93 99.93 Example 7 ─ ─────────────────────────────────── O 2.0 1.0 Outer surface to 100 μ 99.98 99.98 Example 7 ── ────────────────────────────────── P 1.0 0.5 Uniform to the inside 98.90 95.94 Comparative Example 5 ───── ─────────────────────────────── Q-1.0 Even inside 99.90 96.23 Comparative example 6 ───────── ──────────────────────────── From the results of Table 2, catalysts J, K according to Example 6 and Example 7 of the present invention, N and O do not contain phosphorus in the carrier and serve as a catalyst auxiliary component together with platinum, which is the main catalyst component, in titania. (A) A catalyst that is supported on the surface of a carrier and has a phosphorus content, a platinum loading amount, and a loading state within the scope of the present invention.The use of such a catalyst of the present invention causes decomposition of trichlorethylene. It can be seen that can be efficiently performed for a long time.

On the other hand, the catalysts L and M according to Comparative Example 4 contained phosphorus as the auxiliary catalyst component outside the range of the present invention, and although these catalysts had a considerably high initial performance, they did not stand for a long time. Then, the catalytic activity is deteriorated and the decomposition efficiency of trichlorethylene is reduced. From this, the supported amount of phosphorus when supported on the carrier as a catalyst component is in an appropriate range, that is, 1 to 3% by weight in terms of oxide.
Within the range, the solid acidity of the catalyst is increased, and there is also an effect of increasing the active sites by interaction with the main catalyst component, which can contribute to the maintenance of the continuous catalyst activity. It can be seen that, when is out of the range of the present invention, such an effect is reduced.

In the catalyst P of Comparative Example 5, both the supported amount of phosphorus and the supported amount of platinum are within the scope of the present invention, but both catalyst components are uniformly supported inside the carrier without alkali treatment of the carrier. Therefore, although the initial activity is high, it can be seen that the catalyst deteriorates and the decomposition efficiency of trichlorethylene decreases when used for a long period of time.

Further, the catalyst Q according to Comparative Example 6 is a catalyst according to the conventional method in which only platinum as a catalyst component is uniformly supported on the inside of the carrier on the titania carrier, but the catalyst J of the present invention containing the same amount of platinum. It can be seen that the initial performance is lower than that of, and the long-term performance is also significantly reduced.

[0058]

As described above, the catalyst of the present invention, that is, the titania carrier, contains phosphorus within the content range of the present invention, or phosphorus is mainly contained within the supported amount range of the present invention as a catalyst auxiliary component. The catalyst according to the present invention, which is supported together with the catalyst component, and the supported catalyst component is supported on the surface of the carrier, can efficiently decompose and remove the volatile organic halogen compound for a long time by reducing the amount of the catalyst component supported. Therefore, it can be said that the invention is industrially excellent.

Claims (7)

[Claims] 1. Titanium is used as a carrier, and 0.1 to 2% by weight of at least one metal selected from the metal group consisting of platinum, palladium, and ruthenium is used as a catalyst supporting component.
A catalyst for decomposing a volatile organic halogen compound, which further comprises a small amount of phosphorus in the catalyst supported on the outer surface of the carrier in a supported amount. 2. The catalyst for decomposing a volatile organic halogen compound according to claim 1, wherein phosphorus is contained as a carrier component in the titania carrier. 3. The catalyst for decomposing volatile halogen compounds according to claim 2, wherein the content of phosphorus contained in the titania carrier is 1 to 5% by weight. 4. The catalyst for decomposing a volatile organic halogen compound according to claim 1, wherein phosphorus is supported on the carrier as a catalyst auxiliary component. 5. The amount of phosphorus supported on the carrier is 1 to
The catalyst for decomposing a volatile organic halogen compound according to claim 4, which is 3% by weight. 6. A titania hydrate cake produced by hydrolyzing a titanium salt is added with phosphoric acid to be kneaded for plasticization, and this is molded and fired to obtain a phosphorus-containing titania carrier, The phosphorus-containing titania carrier is treated with an alkaline solution, and then the carrier is immersed in a salt solution of at least one metal selected from the group of metals consisting of platinum, palladium and ruthenium, and the metal is placed on the outer surface of the carrier. A method for producing a catalyst for decomposing a volatile organic halogen compound, which comprises supporting the catalyst on a substrate. 7. A titania hydrate cake produced by hydrolyzing a titanium salt is obtained by a conventional method, the titania carrier is treated with an alkaline solution, and then the carrier is treated with platinum, palladium or ruthenium. Decomposing a volatile organohalogen compound, characterized in that the metal and phosphorus are supported on the outer surface of the carrier by immersing in a mixed solution of a salt of at least one metal selected from the group consisting of For producing catalyst for automobile.