JPH09141104A - Catalyst for producing chlorine from hydrogen chloride - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a catalyst used when chlorine is produced by oxidizing hydrogen chloride and capable of withstanding long-term use under a low oxygen concn. condition by adding copper, alkali metal and rare earth metal or chromium, copper, alkali metal and rare earth metal to a catalyst based on chromium oxide. SOLUTION: This catalyst used when chlorine is produced by oxidizing hydrogen chloride is prepared by adding copper, alkali metal and rare earth metal or chromium, copper, alkali metal and rare earth metal to a catalyst based on chromium oxide. The catalyst based on chromium oxide is obtained by baking a mixture of a reaction product of a chromium salt with ammonia or a compd. discharging ammonia and a silicon compd. at 800 deg.C or lower. Further, potassium is used as alkali metal and lanthanum is used as rare earth metal and copper, potasium and lanthanum are respectively added to chromium in the catalyst in ratios of 0.01-0.3, 0.005-0.2 and 0.01-0.3.

Description

Detailed Description of the Invention

[0001]

The present invention relates to an improved catalyst for use in the production of chlorine by the catalytic oxidation of hydrogen chloride.
The present invention relates to a method for producing the same, and a method for producing chlorine from hydrogen chloride using the catalyst. Chlorine is produced on a large scale by electrolysis of salt, but it is difficult to balance demand with co-produced caustic soda. On the other hand, a large amount of hydrogen chloride is produced as a by-product during the chlorination reaction of organic compounds or the reaction with phosgene. It is costly and wastefully discarded. Therefore, if chlorine can be efficiently recovered from hydrogen chloride, the demand for chlorine can be satisfied without causing imbalance with caustic soda.

[0002]

2. Description of the Related Art Although there are proposals to use chromium oxide as an oxidation catalyst for hydrogen chloride, no results have been reported showing sufficient performance to withstand industrial use. For example, by impregnating a suitable carrier with an aqueous solution of chromic anhydride or chromium nitrate and thermally decomposing it, hydrogen chloride is circulated at around 400 ° C. to generate chlorine, and after the catalyst is deactivated, A method has been proposed in which the supply is stopped, air is circulated to regenerate the catalyst, and then the air supply is stopped and hydrogen chloride is circulated again (UK Patent No. 584,790).

Further, hydrogen chloride and an oxygen-containing gas are reacted at a reaction temperature of 420 to 430 ° C. and a space velocity of 380 Hr ^-1 by using a catalyst in which dichromate or dark green chromium oxide is carried on a carrier, A hydrogen chloride conversion of equilibrium value of 67.4% has been obtained (UK patent 676,667).
issue). At this time, the conversion rate is 63% at the space velocity of 680 Hr ^-1.
It is. The reaction can be observed even at 340 ° C., but in this case, the space velocity is set to a low value of 65 Hr ⁻¹ and the conversion rate is 52
It's just getting a%. These methods have high reaction temperatures and low space velocities, and are not practical for industrial implementation.

On the other hand, it has been found that a chromium oxide catalyst obtained by firing a compound obtained by reacting an aqueous solution of chromic acid with ammonia at a temperature of 800 ° C. or lower has a high activity for the oxidation reaction of hydrogen chloride. (JP-A-61-2
75104), it has become possible to produce chlorine at a lower temperature and a higher space-time yield than conventionally known catalysts.

However, as a problem of the catalyst,
When used in the oxidation reaction of hydrogen chloride gas, the activity decreases a few months after the start of the reaction, and in order to maintain a high conversion rate, the amount of oxygen required for the oxidation is 2.5 times the theoretical amount. ~ 3
It is necessary to double the amount (excess ratio: 150 to 200%). A method of contacting with hydrogen chloride gas and / or oxygen-containing gas in a high temperature gas phase has been proposed as an activation method at the time of activity reduction (Japanese Patent Laid-Open No. 254846/1987), but a catalyst activated by this method is used as hydrogen chloride. When used in a gas oxidation reaction, the activity returns to that of a new catalyst for several days after the start of the reaction, but after one week or more, the activity begins to decrease, and there is a problem that it cannot withstand long-term use.

As another activation method, there has been proposed a method in which the catalyst is impregnated with an aqueous solution of a chromium salt or chromium oxide, and then the catalyst is calcined at a temperature of 800 ° C. or lower (Japanese Patent Laid-Open No. Hei 3)
If the catalyst activated by this method is also used for the oxidation reaction of hydrogen chloride gas, the activity returns to the level of a new catalyst for several days after the start of the reaction, but the activity starts to decrease after one month or more, There is a problem that it cannot withstand long-term use.

The method for producing chlorine by oxidizing hydrogen chloride using a copper-based catalyst has been known as the Deacon reaction for a long time, and the copper-based catalyst according to the invention of Deacon in 1868 was later treated with copper chloride. Many catalysts in which various compounds are added as the third component to potassium chloride have been proposed.
However, in order to industrially use this catalyst, a sufficient reaction rate cannot be obtained unless the reaction temperature is raised. Therefore, volatilization of the catalyst component occurs, the activity decreases in a short period, and the catalyst life is shortened. It is also known that there is a fatal problem and that the catalyst is solidified, and particularly when used as a fluidized bed catalyst, it becomes difficult to fluidize and cannot be used as a catalyst.

[0008]

An object of the present invention is to solve the problems of the above-mentioned known catalysts in producing chlorine by oxidizing hydrogen chloride, and an object of the present invention is to reduce the oxygen concentration. An object of the present invention is to provide an improved catalyst containing chromium oxide as a main component, which can withstand long-term use under conditions and has a very small decrease in activity, a method for producing the same, and a method for producing chlorine from hydrogen chloride using the catalyst.

[0009]

In order to solve the problems of the present invention, the present inventors have proposed a method for preparing an improved highly active chromium oxide-based catalyst for use in the production of chlorine by oxidizing hydrogen chloride. Diligently studied.

As a result, we have obtained hydrogen chloride obtained by adding components of copper, alkali metal and rare earth metal, or chromium, copper, alkali metal and rare earth metal to a catalyst containing chromium oxide as a main component. A catalyst for producing chlorine by oxidizing with an oxygen-containing gas has a higher activity than a conventionally known catalyst containing chromium oxide as a main component, and there is almost no decrease in activity over time, and the activity under low oxygen concentration conditions is further increased. It has been found that it is extremely effective for maintenance, and that it can withstand industrial use for a long period of time without causing the above-mentioned problems such as volatilization of catalyst components of conventional copper-based Deacon catalysts and solidification during reaction. I found it.

Further, a conventional catalyst containing chromium oxide as a main component is used in a reaction for producing chlorine from hydrogen chloride, and a catalyst having reduced activity is used as a catalyst containing copper, an alkali metal, and a rare earth metal, or chromium, copper, an alkali metal. , And activate the chromium oxide catalyst whose activity has decreased by adding a rare earth metal component,
The present invention has been completed to find a method for regenerating a chromium oxide catalyst which can be regenerated and which does not cause the above-mentioned problems of the conventional method for regenerating a chromium oxide catalyst and can withstand industrial use for a long time.

That is, the present invention is as follows. (1) Copper, an alkali metal, and a rare earth metal, or chromium, copper, an alkali metal, a catalyst containing chromium oxide as a main component,
And a catalyst for producing chlorine by oxidizing hydrogen chloride with an oxygen-containing gas, which is obtained by adding a rare earth metal component. (2) A catalyst containing chromium oxide as a main component is a catalyst obtained by firing a mixture of a reaction product of a chromium salt and ammonia or a compound that releases ammonia and a silicon compound at a temperature of 800 ° C. or lower (1 ) Catalyst. (3) The catalyst according to (1), wherein the catalyst containing chromium oxide as a main component is used once in the reaction as a catalyst for producing chlorine by oxidizing hydrogen chloride, and the activity is lowered. (4) The catalyst according to (1), wherein the alkali metal is potassium. (5) The catalyst according to (1), wherein the rare earth metal is lanthanum. (6) 0.01 to 0.3 of copper and 0.005 of potassium in atomic ratio with respect to chromium in the catalyst containing chromium oxide as a component.
˜0.2, lanthanum in the ratio of 0.01 to 0.3 (1). (7) In the form after firing, the silicon compound is silicon dioxide, and chromium oxide and silicon dioxide are in a weight ratio of 5/95 to 9
(2) catalyst in the range of 5/5. (8) A step of impregnating a solution containing components of copper, an alkali metal, and a rare earth metal, or chromium, copper, an alkali metal, and a rare earth metal with a catalyst containing chromium oxide as a main component, and the impregnated catalyst. A method for producing a catalyst for producing chlorine from hydrogen chloride, which comprises a step of firing at a temperature of 800 ° C. or lower. (9) Hydrogen chloride characterized by using a catalyst obtained by adding components of copper, an alkali metal, and a rare earth metal, or chromium, copper, an alkali metal, and a rare earth metal to a catalyst containing chromium oxide as a main component. A method for producing chlorine by oxidizing chlorine with an oxygen-containing gas. (10) The method according to (9), wherein oxygen in the oxygen-containing gas is reacted with 1 mol of hydrogen chloride in a range of 1/4 mol to 1 mol.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION A catalyst containing chromium oxide as a main component which is used as a base catalyst in the method of the present invention is, for example, a chromium salt such as chromium nitrate, chromium chloride or a chromium salt of an organic acid, and ammonia or urea. It can be prepared by firing a mixture of a reaction product with a compound that releases a large amount of ammonia and a compound of silicon at a temperature of 800 ° C. or lower. The mixing ratio of chromium and silica is not particularly limited, but it is the weight ratio of Cr ₂ O ₃ and SiO ₂ which is the form after the catalyst is finally calcined and is Cr ₂ O ₃ / SiO ₂
The range of 5/95 to 95/5 is often used.

In the present invention, as a method for adding the components of chromium, copper, alkali metal and rare earth metal to the catalyst containing chromium oxide as a main component, conventionally known catalyst preparation methods such as impregnation method, coprecipitation method and vapor deposition method are used. However, the impregnation method is more effective, and the operation is simple.

As an example of the impregnation method, the above-mentioned chromium oxide is added to copper, an alkali metal, and a rare earth metal, or chromium,
A method of impregnating with a solution containing copper, an alkali metal, and a rare earth metal and firing at a temperature of 800 ° C. or lower can be mentioned.
In the method of the present invention, the use of three components of copper, an alkali metal and a rare earth metal is essential. If any of these components is missing, the activity of the catalyst is not sufficiently improved and the object of the present invention is not achieved.

Specific examples of the chromium component used in the present invention include water-soluble chromium salts such as chromium nitrate and chromium chloride, and water-soluble chromium oxide such as chromic anhydride can also be used. The concentration of chromium salt or chromium oxide is preferably in the range of 5 to 45 wt%. Cr ₂ O ₃ / SiO ₂ = 5/9 in the form after final calcination of the catalyst
It is preferable to set it in the range of 5 to 95/5.

As the copper component, for example, copper nitrate, copper sulfate, copper chloride and copper oxide can be used. Alkali metals and rare earth metals can also be used as nitrates of these metals.
Sulfates, chlorides, oxides and the like can be used, and specific examples of the alkali metal component include potassium nitrate, potassium sulfate, potassium chloride, sodium nitrate, sodium sulfate, sodium chloride, sodium oxide and the like.
Examples of the rare earth metal salt include nitrates such as lanthanum, cerium, praseodymium, neodymium, promethium, samarium and europium, sulfates, halides and oxides, among which lanthanum salts are preferable.

The higher the concentration of copper, the alkali metal, and the rare earth metal, the more the effect is obtained. However, the atomic ratio of copper to chromium of the catalyst containing chromium oxide as the main component is 0.01 to 0.
3, potassium = 0.005-0.2, lanthanum = 0.0
The range of 1 to 0.3 is preferable.

When impregnating chromium, copper, an alkali metal and a rare earth metal in the method of the present invention, before, at the same time and after impregnating a solution containing a chromium component with a solution containing copper, an alkali metal and a rare earth metal. The pre-impregnation method, the simultaneous impregnation method, and the post-impregnation method are all possible, and the impregnation method is not particularly limited, but it is often preferable to impregnate the chromium component before the other components by the pre-impregnation method. .

In the method of impregnating a solution in which the above components are dissolved, the temperature of the solution is usually 25 to 70 ° C.
A temperature range of 5-35 ° C is preferred. The amount of the solution is preferably changed according to the specific surface area of the catalyst for uniform impregnation. Specifically, in a catalyst having a specific surface area of 270 to 320 m ² / g, 0.5 to ² ml is preferable for 1 g of the catalyst, and 200
~ 270 m ² / g, 0.3 to 0.5 m per 1 g of catalyst
l is preferred. Further, if the catalyst is 200 m ² / g or less, it is most suitable for uniform impregnation if the catalyst is wet with a volume of 0.2 ml or less per 1 g of the catalyst.

Regarding the number of impregnation treatments, there is no problem in terms of performance even if the impregnation is divided into several times for impregnation, but in the case of division, it is necessary to repeat impregnation and pre-baking at 150 to 300 ° C several times. Therefore, it is preferable to impregnate a predetermined amount once. For the mixing operation after the impregnation, it is sufficient to shake the container containing the catalyst and the aqueous solution or the organic solvent solution for about one hour so that the entire catalyst is mixed. However, when the wet state of the catalyst is low, this shaking is performed. It is necessary to extend the mixing time several times. Thereafter, the catalyst after the completion of the mixing process is heated to 800 ° C.
It is fired at the following temperature. From the viewpoint of preventing volatilization of the impregnated metal component, a preferable firing temperature is 300 to 650 ° C, and particularly preferably 350 to 550 ° C.

The raw hydrogen chloride used in the production of chlorine using the catalyst of the method of the present invention is usually hydrogen chloride which is a by-product in the chlorination of organic compounds or the reaction with phosgene in the chemical industry. Is economical, but not limited to it.

Oxygen-containing gas is used as an oxidizing agent for hydrogen chloride, and oxygen gas or air is usually used. The type of the reactor can be either a fixed bed or a fluidized bed. However, in the case of a reaction that generates a large amount of heat, such as an oxidation reaction of hydrogen chloride, a fluidized bed that can easily remove heat is often used. In the case of a fluidized bed type, oxygen gas is often used, and in the case of a fixed bed type, air is often used.

The molar ratio of hydrogen chloride used in the reaction to oxygen in the oxygen-containing gas is 1/4 to 1 mol of hydrogen chloride.
1 mol is preferred. These source gases may be diluted with a gas inert to the reaction, such as nitrogen.

The amount of hydrogen chloride supplied to the catalyst bed is 200 to 1800 (Nl / Hr.) / K in the case of the fluidized bed type.
g ^- cat. The range is suitable. Reaction temperature is usually 30
It is frequently used at 0 to 450 ° C, especially 360 to 420 ° C. This reaction can be carried out either under normal pressure or under pressure, but it is often preferable to carry out under normal pressure or 1-10 atg.

The conventionally known catalyst containing chromium oxide as a main component has a reduced activity when used in the reaction for several months to half a year under the above-mentioned reaction conditions, and the conversion rate of hydrogen chloride in the initial stage is 70 to 70%.
What shows 80% becomes 50-60%.

In the method of the present invention, as a catalyst containing chromium oxide as a main component of the base, as described above, a conventionally known catalyst containing chromium oxide as a main component is used for the reaction, and as a result, a waste catalyst whose activity is lowered is used. It is also possible. Such a waste catalyst can be impregnated with a solution containing copper, an alkali metal, and a rare earth metal, or chromium, copper, an alkali metal, and a rare earth metal, and impregnated with the solution to recover the lowered activity.

[0028]

According to the method of the present invention, it is possible to provide a long-lived catalyst having higher activity and less time-dependent decrease in activity than a conventionally known catalyst by a simple method in a reaction for producing chlorine by oxidizing hydrogen chloride. Can be. Further, in the conventional chromium oxide catalyst, a large excess of oxygen is required to maintain the oxidation reaction. However, according to the method of the present invention, it is possible to obtain a catalyst with a small decrease in activity even when it is used for a long period of time in the oxidation reaction of hydrogen chloride under an oxygen amount condition of 1/3 to 1/2 of that of the chromium oxide catalyst. it can. The catalyst thus obtained is, for example,
It has high activity even under a low oxygen concentration condition of an oxygen excess ratio of 50% and has a long-term life performance.

Further, according to the method of the present invention, it is possible to use for a long period of time in the oxidation reaction of hydrogen chloride to activate and regenerate a conventionally known catalyst containing chromium oxide as a main component, which has been reduced in activity. The thus-obtained regenerated catalyst has high activity and has the same performance as the new catalyst even in a long-term life test.

[0030]

EXAMPLES Next, the method of the present invention will be described more specifically by way of examples. The catalyst containing chromium oxide as the main component (hereinafter referred to as chromium oxide catalyst) is disclosed in JP-A-61-2.
Prepared by the method described in 75104.

Example 1 50 g of a chromium oxide catalyst for a fine spherical fluidized bed consisting of 75% by weight of chromia and 25% by weight of silica and having an average particle size of 61 μ was added to C
uCl ₂ .2H ₂ O 6.71 g, KCl 2.85 g,
La (NO ₃₎ after impregnation to ₃ · 6H ₂ O _7.79g was dissolved aqueous solution 25 ml, and calcined 5 hours at 510 ° C.. 40 g of the catalyst after this treatment was filled in a glass fluidized bed reactor having an inner diameter of 1 inch, hydrogen chloride gas was introduced into the fluidized bed at 334 ml / min, and oxygen was introduced at 125 ml / min into the fluidized bed, and the inside temperature of the reaction tube was 380 in an electric furnace. The reaction was carried out under the condition of heating to ℃. The conversion rate of hydrogen chloride on the second day from the start of the reaction was 78%. The conversion rate was 76% on the 30th day from the start of the reaction, and the high activity of 74% was maintained on the 60th day.

Example 2 In exactly the same manner as in Example 1, 75% by weight of chromia, silica 25
50 g of a fine spherical spherical chromium oxide catalyst having an average particle size of 50 μm and containing 50% by weight of Cu (NO ₃ ) ₂ .3H ₂ O 12.72
_{g, KNO 3 5.19g, La (} NO 3) 3 · 6H 2 O
After impregnation with 55 ml of an aqueous solution containing 10.42 g, 55
Baking was performed at 0 ° C. for 5 hours. 40 g of the catalyst after this treatment was used for hydrogen chloride oxidation reaction in exactly the same manner as in Example 1. The conversion rate of hydrogen chloride on the 3rd day from the start of the reaction was 80%, and the conversion rate on the 10th day was 80%. The conversion rate was 77% on the 30th day from the start of the reaction, and the conversion rate was 76% on the 65th day, showing almost the same activity and life as those of Example 1.

Example 3 4 kg of a chromium oxide catalyst for microspherical flow composed of 70% by weight of chromia and 30% by weight of silica and having an average particle diameter of 73 μ was Cu.
_{(NO 3) 2 · 3H 2} O 1825.7g, KCl 54
_{8.8g, La (NO 3) 3} · 6H 2 O 1496.3g
After being impregnated with 5.5 liters of an aqueous solution in which was dissolved, it was baked at 550 ° C. for 5 hours. 4 kg of the catalyst after this treatment was charged into a 4-inch nickel fluidized bed reactor, and the outside was placed in a sand fluidized bath to
Heated to 00 ° C. Hydrogen chloride gas 1400Nl / Hr,
Oxygen gas of 525 Nl / Hr (oxygen excess of 50%) was introduced into the catalyst bed to carry out the reaction. The conversion rate of hydrogen chloride on the 3rd day from the start of the reaction was 81%, and the conversion rate on the 30th day was 78%. 67 days after the start of the reaction, the conversion rate was 77%, and the decrease in activity was extremely small.

Comparative Examples 1 to 3 The use of the three components copper, alkali metal and rare earth metal was essential, and the activity of the catalyst was low even if any one component was lacking. Table 1 shows the results.

[Table 1] << Reaction conditions >> ・ Device used for reaction: Glass fluidized bed reactor with inner diameter of 1 inch ・ Amount of catalyst used for reaction: 40 g ・ Amount of waste hydrogen chloride gas: 334 ml / min ・ Amount of oxygen: 167 ml / min ・ Reaction temperature: Electricity Heat the inner temperature to 380 ° C in the furnace. Base catalyst used for impregnation treatment: same chromium oxide catalyst as used in Example 1

Comparative Examples 4 and 5 Table 2 shows the results of the confirmation that there is a problem that the activity of the Deacon catalyst is lowered and the catalyst is solidified.

[Table 2] << Reaction conditions >> ・ Device used for reaction: Glass fluidized bed reactor with inner diameter of 1 inch ・ Amount of catalyst used for reaction: 20 g ・ Amount of waste hydrogen chloride gas: 167 ml / min ・ Amount of oxygen: 84 ml / min ・ Reaction temperature: Electricity Heat the inner temperature to 380 ° C in the furnace.・ Impregnated medium: Silica gel CARiACT =
Fuji Silysia Chemical Co., Ltd.

Example 4 40 g of a chromium oxide catalyst for a fine spherical fluidized bed consisting of 75% by weight of chromia and 25% by weight of silica and having an average particle size of 60 μ was charged in a glass fluidized bed reactor having an inner diameter of 1 inch. Waste hydrogen chloride gas 334ml / min, oxygen 167ml / m
Into the fluidized bed with in and outside the reaction tube with an electric furnace at an internal temperature of 38
The mixture was heated to 0 ° C. and reacted. The conversion rate of hydrogen chloride on the third day from the start of the reaction was 73%. The conversion rate was 67% on the 30th day from the start of the reaction, and it decreased to 55% on the 65th day. At this point, the catalyst was extracted and CuCl ₂ · 2H ₂ O 10.7
2g, KCl 4.72g, La (NO 3) 2 · 3H 2 O
_{(NO 3) 3 · 6H 2} O 12.48g aqueous solution was dissolved 5
After impregnating with 0 ml, the mixture was baked at 510 ° C. for 5 hours. 40 g of this regenerated catalyst was reacted in the same manner as above. Reaction start 3
The conversion rate of hydrogen chloride on the day was 77%, and the conversion rate on the 10th day was 72%. Conversion rate 68% 30 days after the start of the reaction
The conversion was 58% on the 65th day, showing the same activity and life as the new catalyst.

Example 5 In the same manner as in Example 4, the catalyst whose activity was lowered by using it for 65 days was added to 15 ml of 25% nitric acid aqueous solution in which 3.14 g of La ₂ O ₃ was dissolved, and further CuCl ₂ .2H ₂ O 7 was added. .2g,
40 ml of a solution in which 4.27 g of KNO ₃ was added and dissolved
After impregnating with, was baked at 550 ° C. for 5 hours. This regenerated catalyst 4
0 g was used for hydrogen chloride oxidation reaction in exactly the same manner as in Example 4. The conversion rate of hydrogen chloride on the 3rd day from the start of the reaction was 74%,
The conversion rate on the 10th day was 71%. The conversion rate was 65% on the 30th day from the start of the reaction, and the conversion rate was 57% on the 65th day, showing almost the same activity and life as those of Example 4.

Example 6 Except for the catalyst whose activity was decreased after 65 days of use in exactly the same manner as in Example 4, 9.51 g of Cu (NO ₃ ) ₂ .3H ₂ O and KN were added.
_{O 3 3.87g, La 2 (NO} 3) 3 · 6H 2 O7.79
After impregnation with 40 ml of an aqueous solution in which g was dissolved, the mixture was baked at 550 ° C. for 5 hours. 40 g of this regenerated catalyst was used for the hydrogen chloride oxidation reaction in exactly the same manner as in Example 4. The conversion rate of hydrogen chloride on the 5th day after the start of the reaction was 74%, and the conversion rate on the 10th day was 72%.
Met. 30 days after the start of the reaction, the conversion rate was 64%,
The conversion rate was 59% on the 66th day, which showed almost the same activity and life as those of Example 4.

Example 7 4 kg of a chromium oxide catalyst for a fine spherical fluidized bed consisting of 70% by weight of chromia and 30% by weight of silica and having an average particle diameter of 63 μ
An inch nickel fluidized bed reactor was charged and the outside was heated to 400 ° C. in a sand fluidized bath. Waste hydrogen chloride gas 1400N
The reaction was carried out by introducing 1 / Hr and 1000 Nl / Hr of oxygen gas into the catalyst bed. The conversion rate of hydrogen chloride on the 3rd day from the reaction start was 78%, and the conversion rate on the 30th day was 75%. 67 days after the start of the reaction, the conversion rate decreased to 63%. At this point, the catalyst was extracted and CuCl ₂ · 2H ₂ O 1.072k
g, KCl 0.472kg, La (NO 2) 3 · 6H 2
After impregnation with 5 liters of an aqueous solution in which 1.248 kg of O was dissolved, firing was performed at 510 ° C. for 5 hours. 4 kg of this regenerated catalyst was reacted in the same manner as above. The conversion rate of hydrogen chloride on the 3rd day from the start of the reaction was 79%, and the conversion rate on the 30th day was 74%. At 66 days after the start of the reaction, the conversion rate was 63%, which showed the same activity and life as the new catalyst.

Comparative Examples 6 to 8 The use of the three components copper, alkali metal and rare earth metal was essential, and the catalyst could not be regenerated even if any one component was missing. Table 3 shows the results.

[Table 3] << Reaction conditions >> ・ Device used for reaction: Glass fluidized bed reactor with inner diameter of 1 inch ・ Amount of catalyst used for reaction: 40 g ・ Amount of waste hydrogen chloride gas: 334 ml / min ・ Amount of oxygen: 167 ml / min ・ Reaction temperature: Electricity Heat the inner temperature to 380 ° C in the furnace. -Impregnated catalyst: 6 after the start of the reaction in Example 4
Chromium oxide catalyst with conversion reduced to 58% on day 5

Example 8 40 g of a chromium oxide catalyst for a fine spherical fluidized bed, which comprises 75% by weight of chromia and 25% by weight of silica and has an average particle size of 60 μ, was charged into a glass fluidized bed reactor having an inner diameter of 1 inch. Waste hydrogen chloride gas 334ml / min, oxygen 167ml / m
Into the fluidized bed with in and outside the reaction tube with an electric furnace at an internal temperature of 38
The mixture was heated to 0 ° C. and reacted. Oxygen / hydrogen chloride molar ratio = 1 /
2. The oxygen excess rate is 100%. The conversion rate of hydrogen chloride on the third day from the start of the reaction was 73%. The conversion rate was 67% on the 30th day from the start of the reaction, and it decreased to 55% on the 65th day. This spent catalyst _{Cr (NO 3) 3 · 9H} 2 O 15.3
After impregnating with 8.3 ml of an aqueous solution in which g was dissolved,
Fired for hours. Then CuCl ₂ · 2H ₂ O 10.72
g, KCl 4.72g, La (NO 3) 3 · 6H 2 O
After impregnation with 50 ml of an aqueous solution in which 12.48 g was dissolved, 51
Baking was performed at 0 ° C. for 5 hours. 40 g of this regenerated catalyst was reacted in the same manner as above. The conversion rate of hydrogen chloride on the 3rd day from the start of the reaction was 77%, and the conversion rate on the 10th day was 72%. The conversion rate was 68% on the 30th day from the start of the reaction, and the conversion rate was 65% on the 65th day, which showed activity and life equivalent to or higher than that of the new catalyst.

Comparative Example 9 40 g of a chromium oxide catalyst for microspherical fluidized bed, which comprises 75% by weight of chromia and 25% by weight of silica and has an average particle diameter of 60 μ, was charged into a glass fluidized bed reactor having an inner diameter of 1 inch. Waste hydrogen chloride gas 334ml / min, oxygen 125ml / m
Into the fluidized bed with in and outside the reaction tube with an electric furnace at an internal temperature of 38
The mixture was heated to 0C and reacted. Oxygen / hydrogen chloride molar ratio = 3 /
8, the oxygen excess rate is 50%. The conversion rate of hydrogen chloride on the third day from the start of the reaction was 63%. The conversion rate was 57% on the 30th day from the start of the reaction, and it decreased to 45% on the 65th day.

Example 9 40 g of a chromium oxide catalyst for microspherical fluidized bed, which is composed of 75% by weight of chromia and 25% by weight of silica and has an average particle diameter of 60 μ, was charged into a glass fluidized bed reactor having an inner diameter of 1 inch. Waste hydrogen chloride gas 334ml / min, oxygen 125ml / m
Into the fluidized bed with in and outside the reaction tube with an electric furnace at an internal temperature of 38
The mixture was heated to 0 ° C. and reacted. Oxygen / hydrogen chloride molar ratio = 3 /
8, the oxygen excess rate is 50%. The conversion rate of hydrogen chloride on the third day from the start of the reaction was 63%. The conversion rate was 57% on the 30th day from the start of the reaction, and it decreased to 45% on the 65th day.
Withdrawn catalyst at this _{point, Cr (NO 3) 3 ·} 9H 2 O
After impregnation with 8.3 ml of an aqueous solution in which 15.3 g was dissolved, 5
It was baked at 20 ° C. for 6 hours. Then CuCl ₂ · 2H ₂ O
10.72 g, KCl 4.72 g, La (NO ₃ ) ₃ ·
After impregnation with 50 ml of an aqueous solution in which 12.48 g of 6H ₂ O was dissolved, the mixture was baked at 510 ° C. for 5 hours. 40g of this regenerated catalyst
Was reacted in the same manner as above. The conversion rate of hydrogen chloride on the 3rd day from the start of the reaction was 77%, and the conversion rate on the 10th day was 72%. On the 30th day after the start of the reaction, the conversion rate was 68%, and
The conversion rate was 65% on the 5th day, and the activity and life were equal to or more than those of the new catalyst.

Example 10 A glass fluidized bed reactor having an inner diameter of 1 inch was filled with 40 g of a chromium oxide catalyst for a fine spherical fluidized bed, which comprises 75% by weight of chromia and 25% by weight of silica and has an average particle diameter of 60 μ. The waste catalyst obtained by reacting in the same manner as in Example 7 was extracted, and 8.3 ml of an aqueous solution in which 15.3 g of Cr (NO ₃ ) 3.9H ₂ O was dissolved in this waste catalyst and CuCl ₂ .2H ₂ O 10.
72g, KCl 4.72g, La (NO 3) 3 · 6H 2
After simultaneously impregnating with 50 ml of an aqueous solution in which 12.48 g of O was dissolved, the mixture was baked at 510 ° C. for 5 hours. 40g of this regenerated catalyst
Was reacted in the same manner as above. The conversion rate of hydrogen chloride on the 3rd day from the start of the reaction was 77%, and the conversion rate on the 10th day was 72%. On the 30th day after the start of the reaction, the conversion rate was 68%, and
The conversion rate was 65% on the 5th day, and the activity and life were equal to or more than those of the new catalyst.

Example 11 40 g of a chromium oxide catalyst for microspherical fluidized bed, which comprises 75% by weight of chromia and 25% by weight of silica and has an average particle diameter of 60 μ, was charged into a glass fluidized bed reactor having an inner diameter of 1 inch. Extracting the waste catalyst obtained by the same reaction as in Example 7, after impregnated with an aqueous solution 8.3ml obtained by dissolving _{Cr (NO 3) 3 · 9H} 2 O 20.3g on the waste catalyst, 7 hours at 500 ° C. Baked. After that, CuCl ₂ · 2H ₂ O 13.72 g, KCl
_{5.72g, La (NO 3) 3} · 6H 2 O 14.28
After impregnation with 50 ml of an aqueous solution in which g was dissolved, the mixture was baked at 510 C for 5 hours. 40 g of this regenerated catalyst was reacted in the same manner as above. The conversion rate of hydrogen chloride on the 3rd day after the start of the reaction was 77.
%, The conversion rate on the 10th day was 72%. 3 after starting the reaction
A conversion of 69% was shown on day 0, and a conversion of 6 on day 65.
It was 6%, which showed activity and life equivalent to or better than the new catalyst.

Example 12 As a chromium oxide catalyst, copper was added in the same manner as in Example 1 except that 2.23 g of NaCl was used instead of 2.85 g of KCl.
Using a catalyst prepared by impregnating alkali metal and rare earth metal components, hydrogen chloride and oxygen were reacted under the same conditions as in Example 1. The conversion rate of hydrogen chloride on the second day after the start of the reaction was 7
The conversion was 72% at 5 days and 30 days and 70% at 60 days.

Example 13 Nd was used instead of 7.79 g of La (NO ₃ ) ₃ .6H ₂ O.
(NO ₃₎ except for using ₃ · 6H _{2 O7.89g} Example 1
Using a catalyst prepared by impregnating a chromium oxide catalyst with copper, alkali metal and rare earth metal components in the same manner as in, hydrogen chloride and oxygen were reacted under the same conditions as in Example 1. The conversion rate of hydrogen chloride was 77% on the second day from the start of the reaction, 75% on the 30th day, and 74% on the 60th day.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (31) Priority claim number Japanese Patent Application No. 7-239688 (32) Priority date Hei 7 (1995) September 19 (33) Priority claim country Japan (JP) (72) Inventor Hironori Kamata 30 Asamu-cho, Omuta-shi, Fukuoka Mitsui Toatsu Chemical Co., Ltd. (72) Inventor Kunihiro Yamada 30 Asamu-cho, Omuta-shi, Fukuoka Mitsui Toatsu Chemical

Claims (10)

[Claims] 1. Hydrogen chloride in an oxygen-containing gas obtained by adding a component containing copper, an alkali metal, and a rare earth metal, or chromium, copper, an alkali metal, and a rare earth metal to a catalyst containing chromium oxide as a main component. A catalyst for oxidizing and producing chlorine. 2. A catalyst containing chromium oxide as a main component is a catalyst obtained by firing a mixture of a reaction product of a chromium salt and ammonia or a compound releasing ammonia and a silicon compound at a temperature of 800 ° C. or lower. The catalyst of claim 1. 3. The catalyst according to claim 1, wherein the catalyst containing chromium oxide as a main component is a catalyst which has been used once in a reaction as a catalyst for producing chlorine by oxidizing hydrogen chloride and whose activity has decreased. 4. The alkali metal is potassium.
Catalyst. 5. The catalyst according to claim 1, wherein the rare earth metal is lanthanum. 6. Atomic ratio of 0.01 to 0.3 for copper, 0.005 to 0.2 for potassium, and 0.01 to 0. The catalyst of claim 1 present in a ratio of 3. 7. The calcined form is that the silicon compound is silicon dioxide, and chromium oxide and silicon dioxide are in a weight ratio of 5 /.
The catalyst of claim 2 in the range of 95-95 / 5. 8. A step of impregnating a solution containing components of copper, an alkali metal, and a rare earth metal, or chromium, copper, an alkali metal, and a rare earth metal with a catalyst containing chromium oxide as a main component, and the impregnated solution. A method for producing a catalyst for producing chlorine from hydrogen chloride, comprising the step of firing the catalyst at a temperature of 800 ° C. or lower. 9. A catalyst comprising chromium oxide as a main component, copper,
A method for producing chlorine by oxidizing hydrogen chloride with an oxygen-containing gas, which comprises using a catalyst obtained by adding components of an alkali metal and a rare earth metal, or chromium, copper, an alkali metal, and a rare earth metal. 10. The method according to claim 9, wherein oxygen in the oxygen-containing gas is reacted with 1 mol of hydrogen chloride in the range of 1/4 mol to 1 mol.