JPH0547265B2 - - Google Patents

Description

[Detailed description of the invention]

<Industrial Application Field> The present invention oxidizes and dehydrogenates a monoolefin having 4 to 5 carbon atoms in a gas phase with a molecular oxygen-containing gas,
It relates to a catalyst for producing the corresponding conjugated diolefin. Specifically, the present invention relates to n-butene, 1-butene, cis-2-butene, trans-butene,
Monoolefins with 4 carbon atoms such as 2-butene or monoolefins with 5 carbon atoms such as isopentene are catalytically oxidized and dehydrogenated using a molecular oxygen-containing gas, such as air, to produce 1,3-butadiene or isoprene with high selectivity. The present invention relates to a catalyst that can be obtained in high yield, and furthermore, provides a catalyst that can be used industrially for a long period of time and stably. <Prior Art> Many proposals have been made as catalysts for producing the corresponding conjugated diolefins by subjecting monoolefins to catalytic gas-phase oxidative dehydrogenation. To give a specific example, Japanese Patent Publication No. 26842 (1972) describes a catalyst consisting of nickel, cobalt, antimony, iron, bismuth, phosphorus, tungsten, and molybdenum;
No. 33929 contains a catalyst consisting of molybdenum, bismuth, iron, and silver, and Special Publication No. 1983-3498 contains a catalyst consisting of nickel, cobalt, iron, bismuth, molybdenum, phosphorus, arsenic,
Catalysts containing boron and alkali metals have been disclosed. Other Special Publications No. 5321, Special Publication No. 1973, Special Publications No. 50-
No. 11886, JP-A-48-32807, JP-A-54-52010
No., JP-A-48-514, JP-A-49-13102, JP-A-51-93793, JP-A-51-105011, JP-A-57
-209232 has a catalyst system containing molybdenum, bismuth, and iron, and JP-A-49-14393 has a catalyst system containing molybdenum, bismuth, and iron.
A catalyst system containing bismuth and tungsten was
No. 49-9490, JP-A-49-72203, JP-A-49-
No. 101304 contains a catalyst system containing molybdenum, bismuth, tungsten, and iron.
No., JP-A-56-140931, JP-A-56-150023,
JP-A-57-123122 contains molybdenum, bismuth,
Catalyst systems containing chromium are each disclosed. <Problems to be Solved by the Invention> However, when considering the use of these proposed catalysts on an industrial scale, as described in their specification examples, conjugated diolefins cannot be processed with high selectivity and high yield. In many cases, it is not possible to obtain a high rate. This is because the catalytic gas phase reaction is extremely exothermic, so local abnormally high temperature zones called hot spots occur in the catalyst bed, causing an excessive reaction, or because the height of the catalyst packed bed is large. It is conceivable that the reaction may deviate from an ideal reaction because the pressure in the layer changes sequentially from the inlet to the outlet of the catalyst layer. On the other hand, in multicomponent catalysts mainly composed of molybdenum, molybdenum easily reacts with many elements to form complex molybdenum complex salts, making it difficult to obtain homogeneous catalysts and the reproducibility of catalyst performance. It is quite understandable that when such a catalyst composition is used for catalytic production on an industrial scale, the performance of all the produced catalysts cannot show the high level as shown in the examples in the specification. <Means for Solving the Problems> The present inventors have overcome the drawbacks in such industrial use of catalyst systems containing molybdenum, bismuth and tungsten, and yet have achieved reproducibility of catalyst performance in catalyst production on an industrial scale. As a result of intensive research into an excellent preparation method, the present invention has been completed. That is, the present invention is based on the general formula Mo ₁₂ Co _{2.0 to 10.0} A _a B _b C _c (Bi _d W _e Fe _f D _g ) O _h (where Mo is molybdenum, Co is cobalt,
Bi is bismuth, W is tungsten, Fe is iron, A is at least one element selected from nickel and lead, B is potassium, rubidium,
At least one element selected from cesium and thallium, C is silicon, aluminum,
At least one element selected from titanium and zirconium, D is magnesium, calcium,
At least one element selected from cerium, O, represents oxygen. Also, subscripts a, b, c,
d, e, f, g, h represent the atomic ratio of each element, and when molybdenum is 12, a = 0.0 ~
10.0 (however, the sum of the atomic ratio of Co and a does not exceed 10.0), b = 0.1 to 3.0, c = 0.1 to 5.0, d = 0.1 to
5.0, e=0.5~10.0, f=0.1~5.0, g=0.1~3.0,
h takes a value determined by the atomic ratio of each element. ), and at the time of its preparation, Bi, W,
For the production of conjugated diolefin with high performance and long life, characterized by using a material obtained by pre-mixing the raw materials of each component of Fe and D and further processing at a high temperature of 600 to 900 ° C. A method for producing a catalyst is provided. <Function> A feature of the catalyst of the present invention is that the Bi, W, Fe, and D components of the catalyst composition have extremely stable and unique bonds, and furthermore, the catalyst containing these stable compounds can be used to produce monomers. In the case of oxidative dehydrogenation of olefin, the objective is to maintain a stable high yield over a long period of time. This stable bond of Bi, W, Fe, and D components is formed by treating a mixture of these component elements at a high temperature of 600 to 900°C. One of the inventors previously prepared a Bi-W compound (bismuth tungstate) by treating it at high temperature, and combined this compound with Mo-Fe-Co-
(At least one element selected from Ni, Mg, Ca, Ce, Pb) - (At least one element selected from alkali metals) - (At least one element selected from silicon, aluminum, titanium, zirconium) Based on the discovery that a catalyst obtained by mixing a composition consisting of at least one element) is an excellent catalyst for producing conjugated diolefins, the patent application was filed. After that, as a result of intensive research on catalysts based on this bismuth tungstate, we found that when preparing this bismuth tungstate,
Compounds obtained by adding Fe and D components (at least one element selected from Mg, Ca, and Ce) are recognized as stably bonded composite oxides,
When this composite oxide is mixed with the other components mentioned above and used as a catalyst to perform the gas phase reaction of monoolefin, the catalytic activity is further improved and the conjugated diolefin can be collected for a long period of time even at high raw material concentrations. It was found that the rate was high and stable. At the same time, as a result of the long-term reaction, it was found that the precipitation of carbon on the catalyst was greatly reduced compared to conventionally known catalysts, and this led to the development of a catalyst that is extremely useful industrially, and the completion of the present invention. It came to this. The catalyst preparation method according to the present invention employs a generally known preparation method, except that the complex oxide having the composition (Bi-W-Fe-D) described above is used when preparing the catalyst. be able to. Next, an example of catalyst preparation is shown below. (1) Preparation of composite oxide with component composition (Bi-W-Fe-D) First, a bismuth compound (e.g. bismuth nitrate, bismuth hydroxide, bismuth oxide, etc.) and a tungsten compound (e.g. ammonium paratungstate, tungsten oxide, etc.) are prepared. ) and a small amount of water. Here, an aqueous solution of an iron compound (for example, ferric nitrate, ferric hydroxide, etc.) and a D component compound (D component nitrate,
Add an aqueous solution or slurry of hydroxide, carbonate, oxide, etc. and mix well. After heating and concentrating the slurry thus obtained and drying it,
The composite oxide is calcined for 1 to 10 hours at a high temperature of 600 to 900°C, preferably 700 to 850°C, under air flow or inert gas flow such as nitrogen, and is pulverized into about 100 meshes. (2) Preparation of catalyst Add aqueous solutions of a Co compound (e.g. cobalt nitrate), component A (e.g. nickel nitrate) and component B (e.g. potassium nitrate) to an aqueous solution of a molybdenum compound (e.g. ammonium molybdate) and mix well. Add component C (e.g. colloidal silica) and stir well. The (Bi-W-Fe-D) composite oxide powder prepared in (1) is added to the resulting slurry, mixed well, and concentrated by heating. After molding and drying the resulting clay-like material, it is heated to 350-650℃, preferably
The catalyst is calcined at a temperature of 400 to 600° C. for 1 to 15 hours under air flow or inert gas flow. In addition to the times shown above, the timing of addition of the (Bi-W-Fe-D) composite oxide, which is a feature of this catalyst, is
It is also possible to separately prepare a dry powder with the component composition (Mo-Co-A-B-C), mix the two powders, mold the powder, and use it as a catalyst after firing. In addition to these preparation methods, any method can be adopted as long as each catalyst component in the catalyst composition can be uniformly mixed. For example, (Bi-W-Fe-D) composite oxidation powder of things,
It is also possible to prepare a catalyst by mixing it with a mixture of oxide powders of each of the other catalyst components, adding a binder (for example, carboxymethyl cellulose, etc.), molding, and calcining. Moreover, the composite oxide (Bi _d W _e Fe _f D _g ) used in the present invention
The ratio of the constituent elements is preferably in the range of d+f+g/e=0.5 to 4.0 in terms of atomic ratio. The catalyst raw materials in the present invention are not limited to the above-mentioned compounds, and for bismuth and tungsten, bismuth halides such as bismuth chloride, bismuth salts of organic acids such as bismuth carbonate, bicarbonate, bismuth hydroxide, and bismuth acetate are used. Alkali metal salts of tungstic acid such as sodium tungstate and tungsten halides such as tungsten chloride are used as appropriate, but when halides or alkali salts are used, thorough cleaning is required after passing through the slurry. It goes without saying that there is. Regarding molybdenum, iron, and other catalyst raw materials, not only nitrates and organic acid salts, but also any compounds that can form their respective oxides can be used in the preparation of the catalyst. Of course, compounds containing two or three of the elements constituting the above catalyst may also be used. In addition, carrier materials can be used as appropriate for the above catalyst components, such as clay, diatomaceous earth, asbestos, Celite (trade name), silica,
A granular support such as alumina, silica/alumina, etc. can be used as a support base. When the oxidative dehydrogenation reaction of monoolefins is carried out using the catalyst of the present invention obtained as described above, the yield and selectivity of conjugated diolefins are greatly improved, and even when a high concentration raw material gas is used, it is sufficient. It was found that it has excellent performance and maintains stable performance even in long-term reactions. It was also found that even during long-term reactions, there was very little carbon precipitation on the catalyst, making it an extremely advantageous catalyst from an industrial perspective. The reason for this effect is that the present invention was used (Bi-W
-Fe-D) This is due to the specific action of the complex oxide, and its scientific structure and action are not yet fully elucidated. This is thought to be due to improved effects such as 250 to 400 using the catalyst obtained in this way.
℃ reaction temperature, under pressure of normal pressure to 10 atm, 2-20% by volume monoolefin, 2-20% by volume oxygen, 0
A raw material gas consisting of ~60% by volume of water vapor and 20~80% by volume of an inert gas such as nitrogen gas or carbon dioxide gas is reacted for a contact time of 0.5~5.0 seconds. Note that the monoolefin having 4 to 5 carbon atoms, which is a raw material, does not necessarily have to be used in the form of isolated 1-butene, trans-2-butene, cis-2-butene, or isopentene. For example, when a so-called spent B-B fraction containing n-butene as a main component obtained by separating 1,3-butadiene and isobutylene from a _C4 fraction produced as a by-product in the cracking of naphtha is used as a monoolefin mixture having 4 carbon atoms. Also, 1,3-butadiene can be obtained in almost the same yield as when using high-purity n-butene as a raw material. Furthermore, the catalyst according to the present invention can be used in both fixed bed reactions and fluidized bed reactions.
The selection can also be made appropriately by those skilled in the art. EXAMPLES Hereinafter, the present invention will be explained in more detail by showing examples and comparative examples, but the present invention is not limited to the following examples unless it goes against the gist thereof. In addition, the reaction rate, selectivity, and single flow yield in this invention shall be defined as follows. Reaction rate (mol%) = Number of moles of monoolefin reacted/supplied
〃 ×100 Selectivity (mol%) = Number of moles of diolefin produced / Number of moles of monoolefin reacted × 100 Single flow yield (mol%) = Number of moles of diolefin produced / Number of moles of monoolefin supplied × 100 Example 1 291 g of bismuth nitrate was dissolved in 200 ml of water made acidic by adding 45 ml of concentrated nitric acid. 278 g of tungsten trioxide was added to this and mixed well. Further, an aqueous solution of 71 g of ferric nitrate dissolved in 50 ml of water and an aqueous solution of 13 g of magnesium nitrate dissolved in 15 ml of water were added and mixed well. This was concentrated by heating, dried, and then calcined at 750° C. for 2 hours under air circulation. The obtained fired product was crushed into about 100 pieces. Separately, add 1060 g of ammonium molybdate to 8000 g of water.
600ml of 960g of cobalt nitrate dissolved in ml of aqueous solution
An aqueous solution of 20 g of cesium nitrate dissolved in 200
An aqueous solution dissolved in ml of water and 150 g of silica sol containing 20% by weight of silica were each added and stirred well. The slurry prepared previously (Bi-W-
Powder of composite oxide (Fe-Mg) was added, mixed well, and concentrated by heating. The resulting clay-like substance is sized to a diameter of 5.5 mm.
The catalyst was molded into a pellet with a length of 7 mm and a length of 7 mm, and after drying, it was calcined at 500°C for 6 hours under air circulation to obtain a finished catalyst. The composition of this catalyst (excluding oxygen) was Mo ₁₂ Co _6.6 Cs _0.2 Si _1.0 Bi _1.2 W _2.4 Fe _0.35 Mg _0.1 in atomic ratio (hereinafter, the catalyst composition will be expressed in the same manner). The thus obtained catalyst was packed into a steel reaction tube with an inner diameter of 25.4 mmφ to a layer length of 3000 mm, the external catalyst (molten salt) was heated to 330°C, and 1-butene 13.0% by volume, oxygen 13.0% by volume, and water vapor were added. 10.0% by volume, nitrogen
A raw material gas having a composition of 64.0% by volume was introduced, and the reaction was carried out for a contact time of 1.0 seconds (in terms of NTP), and the results shown in Table 1 were obtained. Table 1 also shows the results when this reaction was continued for 1000 hours. Note that no carbon precipitation was observed on the catalyst taken out after 1000 hours of reaction. Analysis was performed using gas chromatography. Examples 2, 3 Using the same catalyst obtained in Example 1, 1
The reaction was carried out under the same conditions as in Example 1, except that -butene was replaced with cis-2-butene or trans-2-butene and the reaction temperature was 340°C, and the results shown in Table 1 were obtained. Example 4 291 g of bismuth nitrate was dissolved in 200 ml of water made acidic by adding 45 ml of concentrated nitric acid. 278 g of tungsten trioxide was added to this and mixed well. Then, an aqueous solution of 81 g of ferric nitrate dissolved in 60 ml of water and 43 g of ceric oxide were added and mixed well.
After heating and concentrating this and drying it,
It was baked at 750°C for 2 hours. The obtained fired product was crushed into about 100 pieces. Separately, add 1060 g of ammonium molybdate to 8000 g of water.
350 ml of cobalt nitrate 582 g dissolved in 350 ml of aqueous solution
An aqueous solution of 291 g of nickel nitrate dissolved in 150
29 g of cesium nitrate, an aqueous solution dissolved in ml of water.
An aqueous solution dissolved in 290 ml of water and 150 g of silica sol containing 20% by weight of silica were added and mixed well. The resulting slurry was concentrated by heating, dried, and then ground. This powder was previously prepared (Bi
-W-Fe-Ce) composite oxide powder was added and thoroughly mixed, water was added and kneaded well, and the mixture was then molded and fired in the same manner as in Example 1 to obtain a catalyst having the following composition. Mo ₁₂ Co _4.0 Ni _2.0 Cs _0.3 Si _1.0 Bi _1.2 W _2.4 Fe _0.4 Ce _0.5The obtained catalyst was used in the same reactor as in Example 1,
Its composition is 1-butene 46.5% in mole%, cis-2
-butene 13.0%, trans-2-butene 18.3%,
Isobutane 3.8%, normal-butane 16.0%, other 2.4
The mixed fraction (B-B fraction) consisting of 17.0% by volume,
When a raw material gas with a composition of 13.0% by volume of oxygen, 10.0% by volume of water vapor, and 60.0% by volume of nitrogen was reacted at a contact time of 1.0 seconds (NTP conversion) and a reaction temperature of 340°C, no reaction was observed for butanes. We obtained the results shown in Table 1. Table 1 also shows the results when this reaction was continued for 1000 hours. Note that no carbon precipitation was observed on the catalyst taken out after 1000 hours of reaction. Example 5 A catalyst having the composition shown in Table 1 was prepared in the same manner as in Example 1. The raw materials used were lead, potassium nitrates, zirconium oxides rubidium, and calcium hydroxides. A reaction was carried out using the obtained catalyst under the same conditions as in Example 4, and the results shown in Table 1 were obtained. Table 1 also shows the results when this reaction was continued for 1000 hours. Note that no carbon precipitation was observed on the catalyst taken out after 1000 hours of reaction. Examples 6 and 7 Catalysts having the compositions shown in Table 1 were prepared in the same manner as in Example 1. The raw materials used were nitrate for thallium, and oxides of titanium and aluminum. The reaction temperature of the obtained catalyst was changed in Example 7.
The reactions were carried out under the same conditions as in Example 4, except that the temperature was 320°C, and the results shown in Table 1 were obtained. Example 8 60 ml of the same catalyst obtained in Example 5 was prepared with an inner diameter of 20
Filled in a steel reaction tube with a diameter of 1.5 mm, and heated at a heating medium temperature of 320°C, isopentene (2-methene-2-butene) 8.0% by volume, oxygen 8.0% by volume, water vapor 10.0% by volume, and nitrogen 74.0%.
Contact time of 1.8 seconds (NTP conversion) for mixed gas of % by volume
was introduced and reacted. The results are shown in Table 1. Comparative Example 1 In Example 1, (Bi-W-Fe-
A catalyst having the same composition as in Example 1 was obtained by mixing each component, heating and concentrating it, molding it, and sintering it without creating a Mg) composite oxide. A reaction was carried out using the obtained catalyst under the same conditions as in Example 1 except that the reaction temperature was 400°C, and the results shown in Table 2 were obtained. Table 2 also shows the results when this reaction was continued for 1000 hours. Comparative Example 2 In Example 1, a composite oxide was prepared in advance using only bismuth and tungsten, and iron and magnesium components were added to a slurry of molybdenum, cobalt, cesium, and silica. I got a catalyst. A reaction was carried out using the obtained catalyst under the same conditions as in Example 1, and the results shown in Table 2 were obtained. Comparative Example 3 In Example 1, the heat treatment temperature of the mixture containing bismuth, tungsten and magnesium was
Example 1 was carried out in the same manner except that the temperature was changed to 550°C.
A catalyst with the same composition was obtained. Using this catalyst, the reaction was carried out under the same conditions as in Example 1 except that the reaction temperature was 400°C. Table 2
The results shown are obtained. Comparative Example 4 In Example 1, the heat treatment temperature of the mixture containing bismuth, tungsten and magnesium was
Example 1 was carried out in the same manner except that the temperature was changed to 950°C.
A catalyst with the same composition was obtained. The reaction was carried out under the same conditions as in Example 1 except that this catalyst was used and the reaction temperature was 400°C, and the results shown in Table 2 were obtained. Comparative Examples 5 and 6 The same catalyst as obtained in Comparative Example 3 was used, the raw material 1-butene was replaced with cis-2-butene and trans-2-butene, and the reaction temperature was 400°C under the conditions of Example 1. Reactions were carried out according to the following procedures, and the results shown in Table 2 were obtained. Comparative Example 7 The same procedure as in Example 5 was carried out except that component D (cerium and calcium) was not used, and Table 2
A catalyst with the composition shown was obtained. A reaction was carried out using the obtained catalyst under the same conditions as in Example 5, and the results shown in Table 2 were obtained. Table 2 also shows the results when this reaction was continued for 1000 hours. Comparative Example 8 In Example 5, (Bi-W-Fe-
A catalyst having the same composition as in Example 5 was obtained by mixing each component into one, heating and concentrating, molding, and sintering without creating a Ce-Ca) composite oxide. A reaction was carried out using the obtained catalyst under the same conditions as in Example 8, and the results shown in Table 2 were obtained.

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Claims (1)

[Claims] 1. When producing a conjugated diolefin by oxidizing and dehydrogenating a monoolefin having 4 to 5 carbon atoms in a gas phase,
The catalyst used has the following general formula: Mo ₁₂ Co _2.0~10.0 A _a B _b C _c (Bi _d W _e Fe _f D _g ) O _h (where Mo is molybdenum, Co is cobalt,
Bi is bismuth, W is tungsten, Fe is iron, A is at least one element selected from nickel and lead, B is potassium, rubidium,
At least one element selected from cesium and thallium, C is silicon, aluminum,
At least one element selected from titanium and zirconium, D is magnesium, calcium,
At least one element selected from cerium, O, represents oxygen. Also, subscripts a, b, c,
d, e, f, g, h represent the atomic ratio of each element, and when molybdenum is 12, a = 0.0 ~
10.0 (however, the sum of the atomic ratio of Co and a does not exceed 10.0), b = 0.1 to 3.0, c = 0.1 to 5.0, d = 0.1 to
5.0, e=0.5~10.0, f=0.1~5.0, g=0.1~3.0,
h takes a value determined by the atomic ratio of each element. ), and at the time of its preparation, Bi, W,
For the production of conjugated diolefin with high performance and long life, characterized by using a material obtained by pre-mixing the raw materials of each component of Fe and D and further processing at a high temperature of 600 to 900 ° C. Catalyst manufacturing method.