JPH07101936A - Production of pyridine - Google Patents

Abstract

PURPOSE:To obtain pyridine having excellent industrial value without causing the lowering of selectivity by combustion reaction and the deterioration of the catalyst by thermal load. CONSTITUTION:Pyridine is produced by the oxidative dealkylation of an alkylpyridine in the presence of a catalyst produced by mixing an oxidation catalyst containing vanadium with titanium oxide having a specific surface area of 20-250m<2>/g and coating an inert carrier with the obtained catalyst powder.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing pyridine by oxidative dealkylation of alkylpyridines.
Pyridine is an extremely useful compound used as a raw material for agriculture and medicine.

[0002]

2. Description of the Related Art Various industrial synthetic methods have been developed for the production of pyridine bases, but all of them produce a considerable amount of alkylpyridines in addition to pyridine. Therefore, it is necessary to control the production ratio of pyridine and alkylpyridines in response to changes in demand structure. In order to respond to such demand changes, for example, in the case of producing pyridine bases using acrolein as a raw material, the ratio is controlled by replacing a part of acrolein with acetaldehyde, but this method also has a limit. Dealkylation of alkyl pyridine is a useful means to control the ratio of pyridine bases. Although a method for producing pyridine by dealkylation includes hydrodealkylation, high pressure is required, and in recent years, oxidative dealkylation by atmospheric pressure reaction has attracted attention.

Regarding the method for producing pyridine by oxidative dealkylation, for example, according to Japanese Patent Publication No. 60-1637, a catalyst obtained by mixing an oxidation catalyst containing vanadium and anatase-type titanium oxide is used to obtain a significantly higher yield than before. The rate is reported to improve.

[0004]

However, the amount of heat generated by the dealkylation reaction is extremely large, and in the case of the conventional columnar catalyst, the heat storage in the catalytically active substance layer is large. In particular, in a locally abnormally high temperature portion called a hot spot, not only the yield decreases due to an excessive oxidation reaction, but also the catalyst life deteriorates due to deterioration of the catalyst due to heat load.

In order to solve such a drawback, the above-mentioned patents adopt a method of diluting a part of the catalyst layer with an inert carrier. However, in the case of this method, it is necessary to find an optimum dilution method according to the activity of the catalyst, and there is a problem of diluting the catalyst, and there are many problems when it is industrially adopted.

[0006]

[Means for Solving the Problems] As a result of intensive studies to solve these problems, the present researcher found that an oxidation catalyst containing vanadium was mixed with titanium oxide having a specific surface area, and It was found that the above problems can be solved by using a catalyst coated on an active carrier, and the present invention has been completed.

That is, "Pyridine is produced by oxidative dealkylation of alkyl pyridine in the presence of a catalyst in which a catalyst powder obtained by mixing an oxidation catalyst containing vanadium and titanium oxide having a specific surface area of 20 to 250 m ² / g is coated on an inert carrier. It is a method for producing pyridine characterized in that it is industrially extremely valuable.

The catalyst of the present invention for producing pyridine from alkylpyridine by oxidative dealkylation comprises an inert carrier and a catalytically active material layer coated and supported on the carrier.

The catalytically active material layer of the present invention comprises an oxidation catalyst containing vanadium and titanium oxide having a specific surface area of 20 to 250 m ² / g. As an oxidation catalyst containing vanadium, as shown in East German Patent No. 59568. Vanadium pentoxide is used as a base, and if necessary, Cr ₂ O ₃ , CdO, Bi ₂ O ₃ , NiO, C in an amount of about 1 to 15% is added to these.
A metal oxide such as oO can be used together. For example, V-Cr oxide, V-Mo oxide, V-W oxide and the like can also be used as the oxidation catalyst containing V.

Further, V-Ag oxides, V-Ag-Cr oxides, V-Ag oxides obtained by adding silver and other metal components to these catalysts.
Ag-Mo oxide, V-Ag-W oxide, V-Ag-S
An oxidation catalyst containing b oxide or the like can be used, and it is particularly preferable to use an oxidation catalyst containing vanadium and silver.

The titanium oxide to be mixed with the vanadium-containing oxidation catalyst of the present invention preferably has a specific surface area in the range of ²⁰ to 250 m ² / g. When the specific surface area of titanium oxide is 20 m ² / g or less, the reaction temperature giving the highest yield becomes high, which is not preferable. On the contrary, the specific surface area is 25
When it is 0 m ² / g, the yield is reduced due to an excessive oxidation reaction, which is not preferable.

The mixing ratio of the vanadium-containing oxidation catalyst of the present invention and the titanium oxide having a specific surface area of 20 to 250 m ² / g can be arbitrarily selected, but titanium oxide is 0.1% with respect to vanadium-containing oxidation catalyst 1. It is in the range of 05-2. Outside of this range, the yield decreases, which is not preferable.

When the mixture of the vanadium-containing oxidation catalyst of the present invention and titanium oxide is coated on an inert carrier, the mixing ratio can be arbitrarily selected, but a preferable range is 0.3 to 2 with respect to 1 part of the carrier. It is a department. If it is less than 0.3 parts, the reaction activity becomes low, which is not desirable. On the other hand, when the amount is 2 parts or more, the catalyst layer becomes thick and the excessive oxidation reaction, which is the object of the present invention, cannot be suppressed, which is not preferable.

As the inert carrier for supporting the catalytically active substance of the present invention, it is possible to use commonly known substances such as silicon carbide, silica, α-alumina, silica-alumina, titania and other refractory materials. I can. The shape of the inert carrier is not particularly limited, and may be spherical, pellet-shaped or ring-shaped. Especially the diameter is 1
A spherical carrier having a size of about 10 mm is preferably used.

In the present invention, as a method for coating the inactive carrier with the catalytically active substance, a general method such as a marumerizer method, a centrifugal fluid coating method, or a method of spraying a slurry containing the catalytically active substance on the carrier is used. It can be supported by a method. Water is generally used as a binder liquid that plays a role of firmly adhering to a carrier, but for the purpose of adhering it more firmly, organic materials such as polyvinyl alcohol, carboxymethyl cellulose and hydroxyethyl cellulose are used. It is also possible to spray an aqueous solution of an adhesive or an aqueous solution of silica sol.

Examples of the raw material for preparing the catalyst of the present invention include ammonium metavanadate, vanadyl chloride, meta- or pyrovanadate, vanadium oxalate, vanadium oxide, and other vanadium compounds, chromium nitrates, hydrochlorides, oxides, and chromic acid. Chromium compounds such as, molybdic acid, ammonium molybdate, molybdenum compounds such as molybdenum oxide, tungsten compounds such as tungstic acid, ammonium tungstate, tungsten oxide, organic acid silver such as silver nitrate, silver acetate, silver lactate, silver oxide, etc. Silver compounds are used.

The method for preparing the catalyst of the present invention is based on a general method for preparing a catalyst of this type. For example, oxalic acid is gradually added while heating an aqueous suspension of ammonium metavanadate to form a uniform solution, and chromium nitrate and silver nitrate are further added to form a uniform solution. Titanium oxide is added to this solution, mixed well, and a uniform slurry is sprayed on an inert carrier, followed by calcination to obtain a catalyst. Alternatively, the slurry is evaporated to dryness, and the resulting cake is dried and then calcined to decompose nitrates. Further, the catalyst is obtained by pulverizing, coating on a carrier by a conventional method and calcining.

The alkylpyridines of the present invention include α
-Picoline, β-picoline, γ-picoline, and other picolines, lutidines, collidines, long-chain alkyl-substituted pyridine derivatives, and / or mixtures thereof, which have one or more alkyl groups in the pyridine nucleus are used.

The oxygen source may be pure oxygen, air having an increased oxygen concentration, or air to which oxygen is not added. For economic reasons it is desirable to use air as the oxygen containing gas.

The steam normally added to the reactor together with the alkyl pyridine and the oxygen-containing gas has the functions of increasing the pyridine yield, and preventing explosion and ensuring safety. From a safety point of view, if necessary, a known inert gas such as nitrogen or argon can be used as a diluent.

The reaction temperature suitable for carrying out dealkylation by bringing a gas containing an alkylpyridine and an oxygen-containing gas into contact with a catalyst varies depending on the kind of the alkylpyridine. For example, in the case of β-picoline, the reaction temperature is 260-260. It is in the range of 380 ° C. Generally speaking, temperatures above the boiling point of the alkyl pyridine and up to about 500 ° C. are used, preferably 24
It is 0-400 degreeC.

The amount of oxygen may be at least the oxygen required to completely oxidize the alkyl group of the alkylpyridine used in the reaction, but supplying more oxygen than necessary lowers the space-time yield of pyridine, It is economically unfavorable, and it is suitable that the molar ratio is 1 to 5 times that of the alkyl group. The supply ratio of water vapor to the alkyl pyridine is not particularly limited, but it is usually preferably 5 mol times or more. However, supplying steam more than necessary reduces the space-time yield of pyridine,
It is economically unfavorable, and a molar ratio of 5 to 35 times is preferable.

The oxidative dealkylation reaction in the present invention can be carried out without any particular pressure limitation.

The contact time of the source gas is 0.5 to 20 seconds (N
TP).

According to the present invention, when the catalyst according to the present invention is used in the method for producing pyridine by oxidative dealkylation of alkylpyridines, the rate of change of alkylpyridines is high, and the oxidation reaction of this kind is This is an industrially excellent method for producing pyridine without any decrease in selectivity due to combustion reaction, which is always a problem, and in particular, without deterioration of the catalyst due to heat load at a locally abnormally high temperature portion called a hot spot.

The present invention will be described in more detail with reference to the following examples, which should not be construed as limiting the present invention.

The rate of change of alkyl pyridine and the pyridine yield in Examples and Comparative Examples are defined by the following formulas.

[0028]

[0029]

Example 1 To 1210 g of ammonium metavanadate, 9000 ml of water was added, heated to 40 to 50 ° C. with stirring, and 540 g of oxalic acid was gradually added to completely dissolve ammonium metavanadate. Next, chromium nitrate 293
0 g was added and dissolved in the aqueous solution of ammonium metavanadate in oxalic acid. Further, add 270 g of silver nitrate to 2000 m of water.
It was dissolved in 1 and the solution was added to the vanadium-chromium solution and stirred sufficiently.

Separately, commercially available titanium oxide sol [MT-A manufactured by Ishihara Sangyo Co., Ltd.] was dried at 110 ° C., and then 300
Heat treatment was carried out at 0 ° C. for 2 hours to obtain titanium oxide having a specific surface area of 190 m ² / g. This titanium oxide (8500 g) was mixed with the above vanadium-chromium-silver-containing aqueous solution, and concentrated with thorough stirring. The cake obtained was dried at 110 ° C. for 5 hours and then heat-treated at 300 ° C. for 2 hours.

[0031]

Example 2 The catalytically active material obtained in Example 1 was pulverized (6
A catalyst active powder was obtained. Freund Sangyo Co., Ltd. MT-A centrifugal fluidized coating granulator C
A carrier (α-Al ₂ O _{3 2} mmΦ) using F-360 and a 0.3% aqueous Poval solution as a binder liquid.
2 kg of catalytically active powder was coated on 1.33 kg. The obtained catalyst was heat-treated at 450 ° C. for 3 hours.

In a reaction tube (inner diameter 27 mmΦ) filled with 60 ml of the obtained coated catalyst, β-picoline: water: air =
A mixed gas having a composition (volume ratio) of 1:16:12 was reacted at a contact time of 6.4 seconds. The results are shown in Table 1.

[0033]

Comparative Example 1 The catalytically active material obtained in Example 1 was pulverized (passed through 32 mesh) to obtain a catalytically active powder. The catalytically active powder was molded into a tablet of 5 mmΦ × 3 mmH by a tableting machine, and then heat-treated at 450 ° C. for 3 hours. The obtained catalyst was reacted under the same reaction conditions as in Example 1. The results are shown in Table 1.

[0034]

[Table 1]

[0035]

Comparative Example 2 A catalytically active powder was prepared in the same manner as in Example 1 except that titanium oxide having a specific surface area of 10 m ² / g was used as a carrier, and a coated catalyst was produced by the method of Example 2.
The reaction was carried out under the same reaction conditions as in Example 2 except that the reaction temperature in Example 2 was changed. As a result, the catalyst layer maximum temperature is 300 ℃
Pyridine yield 53% at 365 ° C Pyridine yield 78%
Met.

[0036]

Examples 3 to 5 Specific surface areas of 50, 90 and 110 m ² /
g of titanium oxide was used, and a catalytically active powder was prepared in the same manner as in Example 1 except that the mixing ratio of the V-Ag-Cr oxidation catalyst and titanium oxide was changed to 29:71, and the method of Example 2 was used. A coated catalyst was prepared and reacted under the same reaction conditions as in Example 2 except that the reaction temperature was changed. The results are shown in Table 2.

[0037]

[Table 2]

[0038]

Examples 6 to 7 Using the catalytically active powder obtained in Example 3,
A spherical catalyst having different active powder coating amounts on 3.5 mm Φα-Al ₂ O ₃ was prepared, and the activity was evaluated at a reaction temperature of 320 ° C. The results are shown in Table 3.

[0039]

Comparative Example 3 100 g of catalytically active component, α-Al ₂ O ₃ 8
The results were shown in Table 3 in the same manner as in Examples 6 to 7, except that the amount of the active ingredient was 00 g and the amount of the active ingredient was about 0.1 part per 1 part of the carrier.

[0040]

[Table 3]

[0041]

Examples 8 to 10 Using the same catalyst as in Example 2, pyridine was produced by oxidative dealkylation of various alkylpyridines. The results are shown in Table 4.

[0042]

[Table 4]

[0043]

Example 11 Table 5 according to the methods of Examples 1 and 2
The catalyst was prepared and the reaction was carried out under the same conditions as in Example 2. The results are shown in Table 5.

[0044]

[Table 5]

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[Procedure amendment]

[Submission date] October 7, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

Title: Method for producing pyridine

[Claims]

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing pyridine by oxidative dealkylation of alkylpyridines.
Pyridine is an extremely useful compound used as a raw material for agriculture and medicine.

[0002]

2. Description of the Related Art Various industrial synthetic methods have been developed for the production of pyridine bases, but all of them produce a considerable amount of alkylpyridines in addition to pyridine. Therefore, it is necessary to control the production ratio of pyridine and alkylpyridines in response to changes in demand structure. In order to respond to such demand changes, for example, in the case of producing pyridine bases using acrolein as a raw material, the ratio is controlled by replacing a part of acrolein with acetaldehyde, but this method also has a limit. Dealkylation of alkyl pyridine is a useful means to control the ratio of pyridine bases. Although a method for producing pyridine by dealkylation includes hydrodealkylation, high pressure is required, and in recent years, oxidative dealkylation by atmospheric pressure reaction has attracted attention.

Regarding the method for producing pyridine by oxidative dealkylation, for example, according to Japanese Patent Publication No. 60-1637, a catalyst obtained by mixing an oxidation catalyst containing vanadium and anatase-type titanium oxide is used to obtain a significantly higher yield than before. The rate is reported to improve.

[0004]

However, the amount of heat generated by the dealkylation reaction is extremely large, and in the case of the conventional columnar catalyst, the heat storage in the catalytically active substance layer is large. In particular, in a locally abnormally high temperature portion called a hot spot, not only the yield decreases due to an excessive oxidation reaction, but also the catalyst life deteriorates due to deterioration of the catalyst due to heat load.

In order to solve such a drawback, the above-mentioned patents adopt a method of diluting a part of the catalyst layer with an inert carrier. However, in the case of this method, it is necessary to find an optimum dilution method according to the activity of the catalyst, and there is a problem of diluting the catalyst, and there are many problems when it is industrially adopted.

[0006]

[Means for Solving the Problems] As a result of intensive studies to solve these problems, the present researcher found that an oxidation catalyst containing vanadium was mixed with titanium oxide having a specific surface area, and It was found that the above problems can be solved by using a catalyst coated on an active carrier, and the present invention has been completed.

That is, "Pyridine is produced by oxidative dealkylation of alkyl pyridine in the presence of a catalyst in which a catalyst powder obtained by mixing an oxidation catalyst containing vanadium and titanium oxide having a specific surface area of 20 to 250 m ² / g is coated on an inert carrier. It is a method for producing pyridine characterized in that it is industrially extremely valuable.

The catalyst of the present invention for producing pyridine from alkylpyridine by oxidative dealkylation comprises an inert carrier and a catalytically active material layer coated and supported on the carrier.

The catalytically active material layer of the present invention comprises an oxidation catalyst containing vanadium and titanium oxide having a specific surface area of 20 to 250 m ² / g. As an oxidation catalyst containing vanadium, as shown in East German Patent No. 59568. Vanadium pentoxide is used as a base, and if necessary, Cr ₂ O ₃ , CdO, Bi ₂ O ₃ , NiO, C in an amount of about 1 to 15% is added to these.
A metal oxide such as oO can be used together. For example, V-Cr oxide, V-Mo oxide, V-W oxide and the like can also be used as the oxidation catalyst containing V.

Further, V-Ag oxides, V-Ag-Cr oxides, V-Ag oxides obtained by adding silver and other metal components to these catalysts.
Ag-Mo oxide, V-Ag-W oxide, V-Ag-S
An oxidation catalyst containing b oxide or the like can be used, and it is particularly preferable to use an oxidation catalyst containing vanadium and silver.

The titanium oxide to be mixed with the vanadium-containing oxidation catalyst of the present invention preferably has a specific surface area in the range of ²⁰ to 250 m ² / g. When the specific surface area of titanium oxide is 20 m ² / g or less, the reaction temperature giving the highest yield becomes high, which is not preferable. On the contrary, the specific surface area is 25
When it is 0 m ² / g, the yield is reduced due to an excessive oxidation reaction, which is not preferable.

The mixing ratio of the vanadium-containing oxidation catalyst of the present invention and the titanium oxide having a specific surface area of 20 to 250 m ² / g can be arbitrarily selected, but titanium oxide is 0.1% with respect to vanadium-containing oxidation catalyst 1. It is in the range of 05-2. Outside of this range, the yield decreases, which is not preferable.

When the mixture of the vanadium-containing oxidation catalyst of the present invention and titanium oxide is coated on an inert carrier, the mixing ratio can be arbitrarily selected, but a preferable range is 0.3 to 2 with respect to 1 part of the carrier. It is a department. If it is less than 0.3 parts, the reaction activity becomes low, which is not desirable. On the other hand, when the amount is 2 parts or more, the catalyst layer becomes thick and the excessive oxidation reaction, which is the object of the present invention, cannot be suppressed, which is not preferable.

As the inert carrier for supporting the catalytically active substance of the present invention, it is possible to use commonly known substances such as silicon carbide, silica, α-alumina, silica-alumina, titania and other refractory materials. I can. The shape of the inert carrier is not particularly limited, and may be spherical, pellet-shaped or ring-shaped. Especially the diameter is 1
A spherical carrier having a size of about 10 mm is preferably used.

In the present invention, as a method for coating the inactive carrier with the catalytically active substance, a general method such as a marumerizer method, a centrifugal fluid coating method, or a method of spraying a slurry containing the catalytically active substance on the carrier is used. It can be supported by a method. Water is generally used as a binder liquid that plays a role of firmly adhering to a carrier, but for the purpose of adhering it more firmly, organic materials such as polyvinyl alcohol, carboxymethyl cellulose and hydroxyethyl cellulose are used. It is also possible to spray an aqueous solution of an adhesive or an aqueous solution of silica sol.

Examples of the raw material for preparing the catalyst of the present invention include ammonium metavanadate, vanadyl chloride, meta- or pyrovanadate, vanadium oxalate, vanadium oxide, and other vanadium compounds, chromium nitrates, hydrochlorides, oxides, and chromic acid. Chromium compounds such as, molybdic acid, ammonium molybdate, molybdenum compounds such as molybdenum oxide, tungsten compounds such as tungstic acid, ammonium tungstate, tungsten oxide, organic acid silver such as silver nitrate, silver acetate, silver lactate, silver oxide, etc. Silver compounds are used.

The method for preparing the catalyst of the present invention is based on a general method for preparing a catalyst of this type. For example, oxalic acid is gradually added while heating an aqueous suspension of ammonium metavanadate to form a uniform solution, and chromium nitrate and silver nitrate are further added to form a uniform solution. Titanium oxide is added to this solution, mixed well, and a uniform slurry is sprayed on an inert carrier, followed by calcination to obtain a catalyst. Alternatively, the slurry is evaporated to dryness, and the resulting cake is dried and then calcined to decompose nitrates. Further, the catalyst is obtained by pulverizing, coating on a carrier by a conventional method and calcining.

The alkylpyridines of the present invention include α
-Picoline, β-picoline, γ-picoline, and other picolines, lutidines, collidines, long-chain alkyl-substituted pyridine derivatives, and / or mixtures thereof, which have one or more alkyl groups in the pyridine nucleus are used.

The oxygen source may be pure oxygen, air having an increased oxygen concentration, or air to which oxygen is not added. For economic reasons it is desirable to use air as the oxygen containing gas.

The steam normally added to the reactor together with the alkyl pyridine and the oxygen-containing gas has the functions of increasing the pyridine yield, and preventing explosion and ensuring safety. From a safety point of view, if necessary, a known inert gas such as nitrogen or argon can be used as a diluent.

The reaction temperature suitable for carrying out dealkylation by bringing a gas containing an alkylpyridine and an oxygen-containing gas into contact with a catalyst varies depending on the kind of the alkylpyridine. For example, in the case of β-picoline, the reaction temperature is 260-260. It is in the range of 380 ° C. Generally speaking, temperatures above the boiling point of the alkyl pyridine and up to about 500 ° C. are used, preferably 24
It is 0-400 degreeC.

The amount of oxygen may be at least the oxygen required to completely oxidize the alkyl group of the alkylpyridine used in the reaction, but supplying more oxygen than necessary lowers the space-time yield of pyridine, It is economically unfavorable, and it is suitable that the molar ratio is 1 to 5 times that of the alkyl group. The supply ratio of water vapor to the alkyl pyridine is not particularly limited, but it is usually preferably 5 mol times or more. However, supplying steam more than necessary reduces the space-time yield of pyridine,
It is economically unfavorable, and a molar ratio of 5 to 35 times is preferable.

The oxidative dealkylation reaction in the present invention can be carried out without any particular pressure limitation.

The contact time of the source gas is 0.5 to 20 seconds (N
TP).

According to the present invention, when the catalyst according to the present invention is used in the method for producing pyridine by oxidative dealkylation of alkylpyridines, the rate of change of alkylpyridines is high, and the oxidation reaction of this kind is This is an industrially excellent method for producing pyridine without any decrease in selectivity due to combustion reaction, which is always a problem, and in particular, without deterioration of the catalyst due to heat load at a locally abnormally high temperature portion called a hot spot.

The present invention will be described in more detail with reference to the following examples, which should not be construed as limiting the present invention.

The rate of change of alkyl pyridine and the pyridine yield in Examples and Comparative Examples are defined by the following formulas.

[0028]

[0029]

Example 1 To 1210 g of ammonium metavanadate, 9000 ml of water was added, heated to 40 to 50 ° C. with stirring, and 540 g of oxalic acid was gradually added to completely dissolve ammonium metavanadate. Next, chromium nitrate 293
0 g was added and dissolved in the aqueous solution of ammonium metavanadate in oxalic acid. Further, add 270 g of silver nitrate to 2000 m of water.
It was dissolved in 1 and the solution was added to the vanadium-chromium solution and stirred sufficiently.

Separately, commercially available titanium oxide sol [MT-A manufactured by Ishihara Sangyo Co., Ltd.] was dried at 110 ° C., and then 300
Heat treatment was carried out at 0 ° C. for 2 hours to obtain titanium oxide having a specific surface area of 190 m ² / g. This titanium oxide (8500 g) was mixed with the above vanadium-chromium-silver-containing aqueous solution, and concentrated with thorough stirring. The cake obtained was dried at 110 ° C. for 5 hours and then heat-treated at 300 ° C. for 2 hours.

[0031]

Example 2 The catalytically active material obtained in Example 1 was pulverized (6
A catalyst active powder was obtained. Freund Sangyo Co., Ltd. MT-A centrifugal fluidized coating granulator C
A carrier (α-Al ₂ O _{3 2} mmΦ) using F-360 and a 0.3% aqueous Poval solution as a binder liquid.
2 kg of catalytically active powder was coated on 1.33 kg. The obtained catalyst was heat-treated at 450 ° C. for 3 hours.

In a reaction tube (inner diameter 27 mmΦ) filled with 60 ml of the obtained coated catalyst, β-picoline: water: air =
A mixed gas having a composition (volume ratio) of 1:16:12 was reacted at a contact time of 6.4 seconds. The results are shown in Table 1.

[0033]

Comparative Example 1 The catalytically active material obtained in Example 1 was pulverized (passed through 32 mesh) to obtain a catalytically active powder. The catalytically active powder was molded into a tablet of 5 mmΦ × 3 mmH by a tableting machine, and then heat-treated at 450 ° C. for 3 hours. The obtained catalyst was reacted under the same reaction conditions as in Example 1. The results are shown in Table 1.

[0034]

[Table 1]

[0035]

Comparative Example 2 A catalytically active powder was prepared in the same manner as in Example 1 except that titanium oxide having a specific surface area of 10 m ² / g was used as a carrier, and a coated catalyst was produced by the method of Example 2.
The reaction was carried out under the same reaction conditions as in Example 2 except that the reaction temperature in Example 2 was changed. As a result, the catalyst layer maximum temperature is 300 ℃
Pyridine yield 53% at 365 ° C Pyridine yield 78%
Met.

[0036]

Examples 3 to 5 Specific surface areas of 50, 90 and 110 m ² /
g of titanium oxide was used, and a catalytically active powder was prepared in the same manner as in Example 1 except that the mixing ratio of the V-Ag-Cr oxidation catalyst and titanium oxide was changed to 29:71, and the method of Example 2 was used. A coated catalyst was prepared and reacted under the same reaction conditions as in Example 2 except that the reaction temperature was changed. The results are shown in Table 2.

[0037]

[Table 2]

[0038]

Examples 6 to 7 Using the catalytically active powder obtained in Example 3,
A spherical catalyst having different active powder coating amounts on 3.5 mm Φα-Al ₂ O ₃ was prepared, and the activity was evaluated at a reaction temperature of 320 ° C. The results are shown in Table 3.

[0039]

Comparative Example 3 100 g of catalytically active component, α-Al ₂ O ₃ 8
The results were shown in Table 3 in the same manner as in Examples 6 to 7, except that the amount of the active ingredient was 00 g and the amount of the active ingredient was about 0.1 part per 1 part of the carrier.

[0040]

[Table 3]

[0041]

Examples 8 to 10 Using the same catalyst as in Example 2, pyridine was produced by oxidative dealkylation of various alkylpyridines. The results are shown in Table 4.

[0042]

[Table 4]

[0043]

Example 11 Table 5 according to the methods of Examples 1 and 2
The catalyst was prepared and the reaction was carried out under the same conditions as in Example 2. The results are shown in Table 5.

[0044]

[Table 5]

Claims (1)

[Claims] 1. A pyridine is produced by oxidative dealkylation of an alkyl pyridine in the presence of a catalyst in which a catalyst powder obtained by mixing an oxidation catalyst containing vanadium and titanium oxide having a specific surface area of 20 to 250 m ² / g is coated on an inert carrier. A method for producing pyridine, comprising: