JPH0436743B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a catalyst composition suitable for producing maleic anhydride by the oxidation of hydrocarbons having 4 or more carbon atoms, especially butane. Vanadium-
It is well known that phosphorus-based composite oxide catalysts are effective. However, although the catalysts proposed in the past (for example, U.S. Pat. No. 3,293,268) are effective in oxidizing unsaturated hydrocarbons such as butenes and butadiene, they are significantly less effective in oxidizing butane, which is a saturated hydrocarbon. It has low activity and requires high reaction temperature,
Furthermore, the yield was not industrially satisfactory. On the other hand, it has also been found that vanadium phosphate compounds having a special crystal structure are effective in the gas phase oxidation of putane. Japanese Patent Publication No. 53-39037 states that the special crystalline phase shown as phase B in Table 1 (1) below is the active species, and that its content in the catalyst is closely related to the activity. In the patent, the average vanadium valence of the catalyst is in the range of approximately +3.9 to +4.6, and the ratio of phosphorus atoms to vanadium atoms in the oxide (hereinafter referred to as P/V) is 0.9 to +4.6. 1.8, and the specific surface area is 7~
50 m ² /g, and in the production of such compositions, vanadium oxide or its precursor is reacted with phosphorus oxide or its precursor in an organic solvent to form a vanadium-phosphorus mixture. It is said that a method of obtaining an oxide, isolating it from an organic solvent, and activating the resulting mixed oxide by heat treatment is essential. The content of phase B of the active ingredient is said to be at least 25%, particularly 50% or more, to exhibit suitable activity. By the way, the crystalline composition of phase B in the same patent is a=b=19.2〓, c=7.8
It is described as having a hexagonal crystal structure. Recently, E. Bordes, P. Courtine, etc. have reported that (VO) ₂ P ₂ O ₇ is the active species of crystalline vanadium phosphate and its crystal structure (J.
Catal., 57 , 236 (1979)). This belongs to the orthorhombic system, a = 9.751 Å, b = 7.738 Å, c = 16.568 Å,
It has a lattice constant of z=4. The main X-ray diffraction peaks match those in Table 2 below, and although there are considerable similarities with phase B, there are some differences, such as the absence of a diffraction peak at 20=15.7° in phase B. On the other hand, JP-A No. 53-61588 describes a vanadium-phosphorous mixed oxide containing W, Sb, Nb, and Mo as promoter components, and its specific surface area is at least
10 m ² /g, especially in the range of 20 to 50 m ² /g,
It is described that it contains phase B in an amount of 50% or more, and that it is produced by reacting a vanadium compound and a phosphorus compound in an organic solvent. In JP-A-53-146992, crystalline vanadium phosphate, which is different from these, is shown in (2) in Table 1 below.
The X phase shown in (3) or the B' phase shown in (3) have been proposed. The catalyst is produced by reacting a vanadium compound with phosphoric acid to produce a solid vanadium-phosphorus mixed oxide, and then contacting this precursor with an acid of 3N or more stronger than phosphoric acid to remove the impurity phase (phase). A process is described which consists in extracting off E) into an aqueous phase, then separating and heating the precursor. The X phase used as the active ingredient is shown in Table 1 and Table 2.
As is clearer, it is a crystalline phase different from phase B or (VO) ₂ P ₂ O ₇ , and the content of this phase in the catalyst is at least 5wt%, preferably 40wt%, and the specific surface area of the catalyst is 7m ² /g or more, preferably
It is said that it should be 10m ² /g or more. Furthermore, the patent stipulates the upper limit of the content of the amorphous vanadium-phosphorous mixed oxide, stating that it should be kept to less than 15 wt%, and that when containing a vanadium-phosphorus mixed oxide other than the X phase, the mixed oxide is specified to exist at least partially as phase B or phase B'.

【table】

[Table] The present inventors have studied methods for producing this crystalline vanadium-phosphorus oxide catalyst, and the one with the best catalytic activity is the one by E. Bordes and P.
We confirmed that (VO) ₂ P ₂ O ₇ as claimed by Courtine et al. As a result of further investigation into the manufacturing method of this (VO) ₂ P ₂ O ₇ , we synthesized in advance a precursor that gives the characteristic X-ray diffraction peaks shown in Table 3 below, and then placed it in an atmosphere of nitrogen, air, etc. _{By firing with}
% crystalline oxide. On the other hand, when a catalyst is produced by the method shown in Japanese Patent Publication No. 53-39037, an oxide solid having a variety of unidentified diffraction peaks and a low crystal purity is usually obtained. Subsequently, we used (VO) ₂ P ₂ O ₇ as the active phase.
We investigated a method of converting a catalyst containing 20% into a molded product with high mechanical strength and high activity and using it as an industrial catalyst. It has been found that the method of applying the active ingredient to a shaped support results in stripping of the catalyst component. On the other hand, the precursor of the active phase as a catalyst for the fixed bed reaction is kneaded with water added if necessary, then molded (tablet method, extrusion molding method, etc.), and then calcined to obtain a molded body of the active ingredient. Although methods have been proposed, they are still considered to be insufficient in terms of both activity and catalytic strength. The use of silica-based carriers, especially colloidal silica solutions, is extremely effective in this respect, and is considered essential especially for producing spherical particle catalysts used in fluidized bed reactions (Japanese Patent Application Laid-Open No. 122944/1983). ,
It was found that the catalyst performance deteriorated significantly. The purpose of the present invention is to provide a catalyst with high mechanical strength without impairing the original activity of the above-mentioned active ingredients, and which contains vanadium and phosphorus and contains
A composition in which a crystalline composite oxide exhibiting a line diffraction peak and silica are uniformly dispersed, wherein () the content of the crystalline composite oxide is 15 to 80% by weight, and () the ratio of phosphorus atoms to vanadium atoms is ratio is 0.8
~1.5, and () the pore volume in the range of pore radius from 37 to 2000 Å
0.01 to 0.3 ml/g, and () the pore volume in the pore radius range of 100 to 350 Å is 50% or more of the pore volume in the pore radius range of 37 to 2000 Å, The gist of the present invention is an oxidation catalyst composition suitable for producing maleic anhydride by oxidizing a hydrocarbon having 4 or more carbon atoms.

[Table] The present invention will be explained in more detail below. In the present invention, a crystalline composite containing substantially tetravalent vanadium and pentavalent phosphorus exhibiting a specific X-ray diffraction peak, that is, the main X-ray diffraction peak shown in Table 2 above, is used as a first component. Use oxides. This compound is known as described above, and can usually be produced by first producing the aforementioned precursor and then firing it. The method for producing the precursor is to reduce pentavalent vanadium such as vanadium pentoxide in a non-oxidizing acidic solution such as hydrochloric acid solution in combination with a reducing agent such as oxalic acid to form tetravalent vanadium ions. A method in which a solution containing vanadium pentoxide is prepared, reacted with phosphoric acid, and the resulting soluble vanadium-phosphorus complex is precipitated by adding water (Japanese Patent Application Laid-Open No. 1983-95990), reacting a pentavalent vanadium compound and phosphoric acid in an aqueous medium in the presence of a reducing agent such as hydrazine hydrochloride or hydroxylamine hydrochloride;
A method of obtaining crystals by concentration or evaporation to dryness (Japanese Patent Application Laid-Open No. 56-45815), or reducing vanadium pentoxide in an organic medium such as ethanol, isopropanol, or glycerol and reacting it with phosphoric anhydride to produce benzene, etc. A method in which crystals are precipitated by azeotropic dehydration with a solvent (US Pat. No. 4,283,288) is known. A precursor of the composite oxide, which is the first component, can be obtained by any of the above methods. This precursor exhibits the main X-ray diffraction peaks shown in Table 3 below.

[Table] In the present invention, it is necessary that the crystalline phosphorus-vanadium composite oxide, which is the first component, has substantially 100% purity. It is necessary to produce a precursor having For this purpose, it is particularly preferable to manufacture by the method shown below. That is, it is produced by dissolving vanadium pentoxide in an aqueous medium to form a homogeneous solution in the presence of phosphoric acid and an inorganic reducing agent, and then hydrothermally treating this solution in a temperature range of 110°C to 250°C. The inorganic reducing agent is preferably hydrazine (usually commercially available as an aqueous solution of hydrazine hydrate) or its phosphate, and hydroxylamine or its phosphate. Other inorganic acid salts, such as hydrochloride, can also be used, but they leave halogen ions behind, which is disadvantageous in terms of reactor material, and are not preferred industrially. Water is generally used as the aqueous medium. Alcohol, carboxylic acid, ethers, if desired
Hydrophilic organic solvents such as ketones may be used in combination, but the amount used should be 50% by weight or less since the reduction rate of vanadium is reduced. Although the P/V atomic ratio of the precursor vanadium-phosphorous crystalline oxide, which is the target product, is 1, the amount of phosphoric acid used is preferably in the range of 0.8 to 1.5. The phosphoric acid concentration in the aqueous medium is between 5 and 50% by weight, preferably between 5 and 45% by weight. If the concentration of phosphoric acid in the aqueous medium is too high, vanadium pentoxide may react with the phosphoric acid before being reduced, and the viscosity of the liquid will also become extremely high, making it difficult to handle. Moreover, if this concentration is too low, the reaction vessel may become too large, which may cause problems. The amount of inorganic reducing agent used is the stoichiometric amount required to reduce pentavalent vanadium to tetravalent vanadium, and
Usually used in the range of 95-120%. The solution obtained in the above manner is then hydrothermally treated at a temperature ranging from 110°C to 250°C, preferably from 120°C to 180°C, in a substantially sealed container to prevent evaporation of water. Do this. Hydrothermal treatment is 0.5~
It is preferable to carry out the test for about 200 hours. When the hydrothermal treatment is carried out in this manner, a slurry containing fine gray-blue crystals is produced. This crystal is a vanadium-phosphorus crystalline oxide precursor, and can be obtained by evaporating the slurry to dryness or directly filtering it from the slurry. This method yields crystalline oxides of fine particle size. An activity promoting component may be added to the first component of the present invention. Active ingredients include iron, chromium, aluminum, titanium, calcium, magnesium,
Examples include metals such as manganese, cobalt, and nickel. An example of a method for introducing these metals into the first component is to add these compounds to the above solution. The compound is not particularly limited as long as it is soluble in the above solution, but preferably inorganic acid salts such as chlorides, sulfates, nitrates, and carbonates, and organic acid salts such as acetates and oxalates. Can be mentioned. In the case of titanium, the use of peroxides is also possible. The timing of addition is preferably before hydrothermal treatment. The amount added should be adjusted to a range of 0.01 to 0.4 mol of metal per mol of vanadium element, more preferably 0.02 to 0.2 mol. The above metal components may be one type or a mixture of multiple types. When such an activity-promoting component is added, the position of the X-ray diffraction spectrum of the obtained precursor and the crystalline composite oxide that is the first component may be slightly shifted, but the range is within ±0.2°. (See JP-A-56-69207 and JP-A-57-111218). If the precursor thus obtained is fired under the conditions described below, it will become a crystalline composite oxide having the peaks shown in Table 2, but in the end it will remain unfired.
It may also be formed into a dry powder containing silica or the like, then molded and fired. The first component itself is highly active, but certain conditions are required as described below in order to enable it to be used not only as a fixed bed catalyst but also as a fluidized bed catalyst like the catalyst of the present invention. be. That is, the final catalyst has pores, and the pore volume of these pores with a radius of 37 to 2000 Å is 0.01 to 0.3 ml/g, preferably 0.03 to 0.3 ml/g.
and more than 50% of the pore volume is the pore radius
It is necessary that it be occupied by pores in the range of 100-350 Å. Pore volume is measured by a commonly used mercury injection method. If the pore volume is too small, the performance of the catalyst will be impaired. Furthermore, if the pore volume is too large, the mechanical strength of the catalyst will be significantly impaired. Furthermore, an important feature of the catalyst of the present invention is that the radius
The presence of a certain amount or more of pores with a pore volume in the range of 100 to 350 Å is important, but if there are many pores with a radius in the range of 100 to 350 Å, the so-called mesobore range, the catalytic activity is improved, and for example, the presence of pores in the final catalyst composition Even if the active ingredient is contained in an amount of at most 35%, a catalyst with the same high activity as the active ingredient alone can be obtained. A catalyst composition having such special physical properties can be produced by the method described below. In the catalyst composition of the present invention, the active ingredient, which is the first component, is supported on the silica carrier, and in this case, the adhesive strength between the active ingredient and the carrier is increased, the active ingredient is uniformly dispersed, Certain second components are also used to provide certain porosity.
This second component is ultimately amorphous vanadium-
Although it is a phosphorus composite oxide, an aqueous solution containing vanadium and phosphorus is used in the catalyst production stage.
It contains substantially tetravalent vanadium and pentavalent phosphorus, at least a portion of which is preferably present as vanadyl phosphate. Next, a method for producing the aqueous solution as the second component will be explained. Generally, it is obtained by adding and dissolving a reducing agent and vanadium pentoxide in an aqueous solution containing phosphoric acid. The molar ratio of phosphorus to vanadium in the aqueous solution is preferably in the range of 0.5 to 10. Aqueous solutions containing vanadyl phosphate are generally unstable;
Oxalic acid can be present to stabilize aqueous solutions, although it may be difficult to keep them stable for long periods of time. The amount is in a molar ratio of oxalic acid to vanadium of 1.2 or less, preferably in the range of 0.2 to 1. If the amount of oxalic acid is too high, it will have an unfavorable effect on the mechanical strength, bulk density and active surface of the catalyst. A range in which the molar ratio of oxalic acid to vanadium is 1.2 or less is a range in which vanadyl oxalate is not formed. Specific examples of methods for producing aqueous solutions include the following methods. First, vanadium pentoxide is added to an aqueous solution containing phosphoric acid and oxalic acid at a molar ratio of oxalic acid to vanadium of 1.7 or less, and preferably 0.7 or more to form vanadyl phosphate and oxalic acid. An aqueous solution containing Specifically, it is produced by dissolving oxalic acid in an acidic aqueous medium containing phosphoric acid, and adding vanadium pentoxide while maintaining the temperature at which reduction proceeds by slight heating. According to this method, after completion of the reduction, 1.2 moles or less of oxalic acid will be present per mole of vanadium atoms. Second, in an acidic aqueous solution containing phosphoric acid,
Adding a reducing agent other than oxalic acid, preferably one or a mixture of two or more selected from hydrazine hydrate, inorganic reducing agents such as hydrochloride or phosphate of hydrazine or hydroxylamine, and organic reducing agents such as lactic acid. , then reduced by adding vanadium pentoxide to obtain a homogeneous aqueous solution containing vanadyl phosphate. After this, oxalic acid is preferably added. Thirdly, vanadium pentoxide, phosphoric acid and phosphorous acid are mixed in an aqueous medium to form tetravalent vanadium ions by the reducing action of the phosphorous acid. When the aqueous solution containing vanadyl phosphate obtained by this method is allowed to stand, a crystalline solid that exhibits a characteristic X-ray diffraction spectrum as shown in Table 4 below precipitates.

[Table] Such precipitation of crystalline solids is not preferable from the purpose of the present invention, and when it is necessary to keep the aqueous solution stable for a long time, it is preferable to add oxalic acid. The aqueous solution containing vanadium and phosphorus described above may contain an organic solvent such as alcohol, ketone, or ether, if necessary. The vanadium-phosphorus-based amorphous composite oxide as the second component that is finally produced by using the aqueous solution containing vanadium and phosphorus is itself a vanadium-phosphorus-based crystal of the first component. Although the activity is significantly lower than that of composite oxides, it has a large effect of dispersing the first component into the catalyst composition, and is particularly effective in dispersing micropores with a radius of 100 Å or less, which are harmful to selective oxidation catalysts. It has a masking effect and can improve the overall activity of the catalyst. In the present invention, in addition to the first component and the second component, silica as a carrier (hereinafter sometimes referred to as the third component) is used. Although any silica can be used, it is preferable to use silica sol in order to obtain a spherical catalyst suitable for fluidized bed reactions. The spherical catalyst is produced by spray drying a slurry of the first, second and third components under controlled conditions. Regarding the usage amounts of the first component, the second component and the third component, the first component should be contained in the final catalyst composition in an amount of 15 to 80% by weight, preferably 20 to 60% by weight.
Weight%. The first component is an active component, and if the amount is less than 15% by weight, there will be a problem in terms of catalytic activity, and if it exceeds 80% by weight, the activity will not improve and on the contrary, the catalytic strength will be affected. A problem arises. The ratio of the first component, second component, and third component must be selected so that the pore distribution of the catalyst is within a certain range. Two components: Third component is 1:0.1~7:0.05~
4, preferably in the range of 1:0.5 to 4:0.5 to 2. Further, it is necessary that the P/V of the catalyst as a whole is in the range of 0.8 to 1.5, more preferably 1.1 to 1.3. The P/V of the first component is essentially 1, and the total P / Balance the V. If this atomic ratio is smaller than 0.8, there will be a problem in terms of catalyst selectivity, and if it is larger than 1.5, it will be disadvantageous in terms of catalytic activity. When the first component is used in the form of a precursor in the production of the catalyst composition, it must be dried and dried before being made into a slurry.
The precursor may be pulverized, or the precursor may be prepared by hydrothermal treatment and then spray-dried and mixed with the second and third components. before mixing again
It can also be used by firing in the temperature range of 300 to 700°C in the presence of air (which may contain butane or butenes as the case may be) or in an inert gas atmosphere such as argon or nitrogen. In terms of catalytic activity, it is preferable to mix the first component with the second component and the third component to form a slurry after firing. The first component, second component, and third component are mixed to a desired amount of active ingredients, preferably made into a sufficiently homogeneous slurry using a continuous wet grinder, etc., and then spray-dried and then calcined. do. Compounds such as iron, chromium, aluminum, titanium, calcium, magnesium, manganese, cobalt, and nickel may be added at the stage of catalyst preparation, that is, at the stage of mixing the first, second, and third components. These compounds may be included in the first component as described above, or may be added to the catalyst preparation step, or both. The amount of the metal compound added in the catalyst preparation step is preferably in the range of 0.0002 to 0.2 moles of metal per mole of vanadium atoms. Spray drying conditions are important in controlling the pores of the final catalyst. Spray drying conditions, e.g. model,
It is well known to those skilled in the art that the physical properties of the catalyst are affected by the amount of liquid supplied, the amount of drying gas, temperature, etc., and it is necessary to find the optimal conditions for each depending on the properties of the specific slurry. Usually, the oxide concentration in the slurry is about 10 to 50%, and the dry concentration in the spray dryer chamber is preferably selected from a range of about 100 to 200℃, and more preferably an oxide concentration of 15 to 45%. It is better to process the slurry at a drying temperature of 110-150℃. If the drying temperature is too high, there is a decrease in the strength of the catalyst, which is usually associated with an increase in large pore size pores. If the oxide concentration is excessive, it becomes difficult to transport the slurry, and the resulting catalyst has poor sphericity, which usually causes problems in fluidity. The firing conditions are not particularly different from those for the first component described above. By the above method, the average particle size is 30~
100μm, preferably 40-70μm, specific surface area 0.5-20
A catalyst composition consisting of substantially spherical particles of m ² /g can be obtained. The specific surface area of the catalyst can be controlled mainly by the second component and the calcination temperature, but if the specific surface area is too small, it is disadvantageous in terms of activity.
On the other hand, if it is too large, the selectivity of maleic anhydride will decrease, so it is preferable to control it within the above range. The catalyst composition obtained as described above has excellent fluidity, strength, and activity, and is particularly suitable as a catalyst for fluidized bed reactions. It can also be used as a catalyst. Even when the amount of the expensive first component is reduced, the catalyst composition of the present invention has the same or higher activity than when the first component is used alone, and is extremely effective as a fixed bed reaction catalyst. It is. The catalyst of the present invention can be effectively used for producing maleic anhydride by oxidizing hydrocarbons having 4 or more carbon atoms. As the hydrocarbon, n-butane, n-butene, isobutene, butadiene, etc. can be used alone or in combination. As described above, according to the present invention, a highly active and high strength catalyst composition suitable for producing maleic anhydride by oxidizing a hydrocarbon having 4 or more carbon atoms is provided. Hereinafter, the present invention will be explained in more detail with reference to Examples. Example 1 (Production of highly pure active ingredient precursor) A crystalline active ingredient precursor exhibiting the X-ray diffraction peaks shown in Table 3 was produced as follows. Pour 38.0 kg of demineralized water, 21.83 kg of 85% phosphoric acid, and 2.85 kg of 80% vitrazine hydrate solution into a pressure-resistant container with a jacket lined with No. 100 glass, and then add 16.40 kg of vanadium pentoxide powder while stirring, being careful not to foam. The mixture was added and dissolved little by little. During this time, in order to suppress the temperature rise due to heat generation and maintain the liquid temperature at 60 to 80°C, a heating medium was circulated inside the jacket to remove heat. The addition of vanadium pentoxide was completed in about 4 hours, and a blue vanadyl phosphate solution was obtained. 1.0 kg of seed crystals were added to this, and then a heating medium at 160°C was circulated inside the jacket to heat it. The liquid temperature was raised to 140℃ in 2 hours,
Hydrothermal treatment was then carried out for 10 hours. During this time, the pressure was approximately 0.24 MPa (gauge pressure). After cooling to 90°C, 10.3 kg of demineralized water was added to adjust the solid concentration in the slurry to approximately 35%, and the slurry was extracted. This solid X
When line diffraction measurements were performed, it was found that the main diffraction peaks shown in Table 3 were exhibited, and it was confirmed that it was a pure crystalline oxide. Also, Coulter
When the particle size distribution of the solid in the slurry was examined using a counter method, it was found to have an average particle size of 0.7 μm. Dry this oxide slurry using a spray dryer,
29.8 kg of light blue oxide powder was obtained. The standard P/V atomic ratio of the oxide slurry is 1.05,
It was confirmed that the crystalline precursor solid obtained by filtering and washing had a compositional formula of (V ₂ O ₄ )(P ₂ O ₅ )(2H ₂ O). Example 2 (Production of high-purity active ingredient) The active ingredient precursor obtained in Example 1 was calcined, and the results shown in Table-
A crystalline oxide having the X-ray diffraction pattern shown in 2 was produced. In other words, in a Matsufuru furnace with a capacity of 500
The precursor obtained in Example 1 was placed in 10 2-volume porcelain dishes.
10 kg were divided and arranged, and after the inside of the furnace was sufficiently replaced with nitrogen gas, the temperature was raised and heated at 550°C for 2 hours. Next, air was gradually introduced into the furnace and the mixture was heated for an additional hour, and then allowed to cool. As a result of X-ray diffraction, the powder after firing did not show any peaks other than the diffraction peaks shown in Table 2, confirming that it was a highly pure active ingredient.
In addition, when the proportion of pentavalent vanadium in all vanadium atoms was measured by redox titration method, it was found to be 23.4.
It was %. That is, at least a portion of the vanadium in (VO) ₂ P ₂ O ₇ can absorb oxygen while maintaining its crystal structure and assume a pentavalent state. Example 3 (Production of vanadium phosphate solution) A vanadium phosphate solution was produced as an example of a suitable raw material for a composite oxide containing amorphous phosphorus and vanadium as main constituent elements. Dissolve 2.956 kg of 85% phosphoric acid in 3.0 kg of demineralized water, and add oxalic acid (H ₂ C ₂ O ₄
2.55 kg of 2H ₂ O) was added and dissolved by heating. The liquid was heated to 80°C, and 1.842 kg of vanadium pentoxide was added little by little while being careful not to foam. After dissolving, the mixture was heated for an additional 10 minutes at boiling to complete the reduction. The liquid was allowed to cool, and demineralized water was added to adjust the total amount to 10.00 kg. The P/V atomic ratio of this solution was 1.2666, and the oxide (V ₂ O ₄ +P ₂ O ₅ ) concentration was 35.0%. Example 4 (Production of Catalyst-1) 393.6 g of the dry precursor powder obtained in Example 1, 1.143 Kg of the vanadium phosphate solution obtained in Example 3, and 625.1 g of a commercially available 40% concentration colloidal silica solution.
A solution prepared by diluting the above with 2.84 kg of demineralized water was mixed and then treated with a continuous wet grinder to thoroughly homogenize it. This slurry was dried using a spray dryer to obtain spherical catalyst particles with an average particle diameter of 58 μm. This is 350
The catalyst was calcined at 500° C. for 1 hour under an air stream and then at 500° C. for 2 hours under a nitrogen stream to obtain Catalyst-1. Example 5 (Production of Catalyst-2) Catalyst-2 was produced in exactly the same manner as in Example 4, except that 353.2 g of the calcined powder obtained in Example 2 was used instead of the dried precursor powder. Example 6 (Manufacture of catalyst-3) 353.2 g of calcined powder obtained in Example 2, P/V atomic ratio 1.160 obtained in the same manner as Example 3, oxide concentration
1589.4 g of a 40% vanadium phosphate solution and 2119.2 g of a commercially available 20% strength colloidal silica solution were mixed and then processed in a continuous wet grinder to achieve thorough homogenization. This slurry with an oxide concentration of 35% was dried using a spray dryer at a drying temperature of 130°C to obtain true spherical catalyst particles with an average particle diameter of 61 μm. This is heated to 500℃
The catalyst was calcined under a nitrogen stream for 2 hours to obtain catalyst-3. Example 7 (Manufacture of catalyst-4) 750 g of calcined powder obtained in the same manner as in Example 2, a vanadium phosphate solution with a P/V atomic ratio of 1.697 and an oxide concentration of 34.5% obtained in the same manner as in Example 3. 1000g and commercially available 40% strength colloidal silica solution
1012.5 g and 1.523 kg of demineralized water were mixed, and then treated with a continuous wet mill to fully homogenize. Add 3.21 kg of water to this slurry to increase the oxide concentration to 20%.
After diluting to 130℃, dry using a spray dryer.
It was dried at ℃ to obtain vacuum catalyst particles having an average particle diameter of 54 μm. This powder was dried in a dryer at 200°C overnight, and then calcined at 500°C for 2 hours under a nitrogen stream to obtain catalyst-4. Comparative Example 1 (Manufacture of Comparative Catalyst-1) Example 3 was prepared without using the calcined powder obtained in Example 2.
Example 4: 1.43 kg of the vanadium phosphate solution obtained in Example 4, 1.25 kg of 40% colloidal silica solution, and 1.32 kg of demineralized water were mixed and spray-dried to obtain spherical catalyst particles with an average particle diameter of 56 μm. Comparative catalyst-1 was obtained by calcining in the same manner as above. Comparative Examples 2 to 5 (Manufacture of Comparative Catalysts 2 to 5) The calcined powder obtained in Example 2, the vanadium phosphate solution obtained in Example 3, and the colloidal silica solution were mixed into various types shown in Table 5. They were mixed in the same proportions, spray dried to obtain vacuum catalyst particles, and fired in the same manner as in Example 4 to obtain Comparative Catalysts 2 to 5. Table 5 shows the catalyst manufacturing method, composition, and physical property measurement results.
and shown in Table-6.

【table】

[Table] Set. The smaller the size, the greater the strength.
Reaction Example 1 Using a 3% n-butane-air mixed gas, a small fluidized bed reactor made of hard glass, and the catalyst 20 shown in Table 7.
ml, GHSV500 was used for activity testing. The reaction products were collected in water and quantitatively analyzed by potentiometric titration of the collected liquid and gas chromatography of the waste gas. The results are shown in Table-7.

【table】

[Table] Reaction Example 2 Catalyst-2, Catalyst-4, Comparative Catalyst-2, and the calcined powder of Example 2 were each ground with a mortar, formed into 7 mmφ x 3 mmH with a tablet machine, and then crushed. hand
14-24 mesh particles were sieved. 6mm of this 1ml
Fill a φ hard glass microreactor,
Mixed gas of n-butane 1.5%/air, GHSV2000
I reacted with The products were analyzed by gas chromatography. Table 8 shows the results of comparing catalyst performance. Catalysts 2 and 4 showed similar results to the calcined powder of Example 2.

[Table] Reaction Example 3 1-Butene, isobutylene, 1,3-
A reaction between butadiene and 1-butene-n-butane mixed gas was carried out. Hydrocarbon concentration is 3% each.
It was set as GHSV500. The reaction results are shown in Table-9.

[Table] Reaction example 4 20ml of catalyst-2 was charged into the small fluidized bed reactor used in reaction example 1, and 3% n-butane and 1-butene were added.
A mixed gas of 0.8% and air was introduced and reacted.
At GHSV500 and reaction temperature of 440°C, n-butane conversion rate is 81.3%, 1-butene conversion rate is 100%, and maleic anhydride yield based on total hydrocarbons is 45.6%.
It was hot.

Claims (1)

[Scope of Claims] 1. A composition in which a crystalline composite oxide and silica containing vanadium and phosphorus and exhibiting the X-ray diffraction peaks shown in the table below are uniformly dispersed, comprising: The content is 15-80% by weight, and the ratio of phosphorus atoms to vanadium atoms () is 0.8
~1.5, and () the pore volume in the range of pore radius from 37 to 2000 Å
0.01 to 0.3 ml/g, and () the pore volume in the pore radius range of 100 to 350 Å is 50% or more of the pore volume in the pore radius range of 37 to 2000 Å. An oxidation catalyst composition suitable for producing maleic anhydride by oxidizing a hydrocarbon having 4 or more carbon atoms. X-ray diffraction peak (opposite negative Cu-Kα) 2θ (±0.2°) 14.2° 15.7° 18.5° 23.0° 28.4° 30.0° 33.7° 36.8° 2 In the oxidation catalyst composition according to claim 1, A pore volume having a pore radius of 37 to 2000 Å and a pore volume of 0.03 to 0.3 ml/g. 3. In the oxidation catalyst composition according to claim 1 or 2, (a) the crystalline composite oxide, (b) the amorphous composite oxide containing vanadium and phosphorus are uniformly dispersed. and (c) silica. 4. In the oxidation catalyst composition according to claim 3, the weight ratio of the crystalline composite oxide (a), the amorphous composite oxide (b), and silica (c) is a:b: c=1:0.1~7:0.05~4.