JPS59162951A - Oxidation catalyst composition - Google Patents

Abstract

PURPOSE:To provide an oxidation catalyst composition holding good activity and mechanical strength, by uniformly dispersing silica and crystalline composite oxide of which the X-ray diffraction peak, the composition and the relation of the fine pore radius and the fine pore volume are specified. CONSTITUTION:Crystalline composite oxide which contains P and V so as to bring the ratio of P-atom to V-atom to 0.8-1.5, and has an X-ray diffraction peak (apposed cathode Cu-Kalpha) shown by the table is uniformly dispersed in a silica carrier. This composition is formed so that the volume of fine pores having a fine pore radius ranging from 37-2,000Angstrom is 0.01-3ml/g and the volume of fine pores having the fine pore radius of 100-350Angstrom is 50% or more of the volume of the fine pore radius of 37-2,000Angstrom . If this oxidation catalyst composition is baked, a catalyst free from the loss of inherent activity, having high mechanical strength and suitable for preparing maleic anhydride by oxidizing 4C or more hydrocarbon is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a catalyst composition suitable for the production of maleic anhydride by the oxidation of a hydrocarbon having a carbon number or more, and butane.

It is well known that vanadium-phosphorous composite oxide catalysts are effective in the process of producing maleic anhydride by gas phase oxidation of hydrocarbons having at least several carbon atoms. However, conventionally proposed catalysts (for example, U.S. Pat. No. 3.2?3
．． Although it is effective in oxidizing unsaturated hydrocarbons such as butenes and butadiene, it has extremely low activity in oxidizing butane, a saturated hydrocarbon, and requires a high reaction temperature. was required, and 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 butane. In Special Publication No. 53-39.0.77,
It is assumed that the special crystalline phase shown as phase B in (1) of Table 1 below is the active species, and its content in the catalyst is closely related to the activity. In that patent, the catalyst has an average vanadium valence of about +3.9 to +9. The ratio of phosphorus atoms to vanadium atoms in the oxide (hereinafter referred to as P/V) is in the range of 0.9 to 8, and the specific surface area is 7 to 8! ; In the production of such compositions, vanadium oxide or its precursor and phosphorus oxide or its precursor are reacted 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. It is said that suitable activity is exhibited when the content of phase B of the active ingredient is at least 15%, particularly so% or more.

By the way, the crystalline composition of phase B in the same patent 3- is a=b=/9.2A〆a=
7. It is described as having a hexagonal crystal structure of tX.

Recently, E. Bordes, P. Courtine et al.
is an active species and reported its crystal structure (
J, Oa ta 1- + proof, ko, y+ (/?7q)
). This belongs to the orthorhombic system, a = ri, 7.1-/A, 1
) = 7. It has a lattice constant of 3gA,c=/A,A;AgA,z=da. The main X-ray diffraction peaks are shown in the table below.
Although there are some similarities with the B phase, there are some differences in the B phase, such as the absence of 2θ=/S and ri° diffraction peaks.

On the other hand, Tokukai Akira! ;3-6/, tgg contains vanadium containing W, Sb, Nb, and Mo as promoter components.
A phosphorus mixed oxide is described, the specific surface area of which is at least as high as VO, in particular in the range -A; Oni''/11, containing phase B in an amount of 30% or more, and containing in an organic solvent. 04-JP-A-Sho!r3/'lt, No. 99.2 describes that crystalline vanadium phosphate is produced by reacting a vanadium compound and a phosphorus compound. Xa shown in (2) of the following table -/ B as shown in (3) of the same
' phase has 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 higher, which is stronger than phosphoric acid, to form an impurity phase ( A process is described which consists in extracting phase E) into an aqueous layer, then separating off and heating the precursor. The X phase, which is the active ingredient, is
As is clear from Table-/ and Table-1, phase B or (■
0) The crystalline phase is different from that of 2P207, and the content of this phase in the catalyst is at least 7% Sw, preferably lI
o wt%, and the specific surface area of the catalyst is 7n? /I or more,
It is said that it should preferably be /OnVl1 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-phosphorous mixed oxide other than the X phase, the content of the mixed oxide is at least partially in phase B or day 2732
reactor.

Table: X-ray diffraction spectra of various crystalline phosphorus-vanadium composite oxides (1) B phase (%Koaki!; No. 3-39,037)
2 and” Uni to Yu A, 3 10/ri, 26 da, g
7/za6563.9
100 s3.0'3, /3
Tag g 2g, s.

;t, 9g 29 30.0a,
A, S-733,1! ;6 (2) X phase (% Kaisho!;, j-/'IA, No. 992) a
(X) ■/Io 2θ (α to Cu-)
+, 1III< / , 20. Oe da, 2
11 </ , 2/, 0″3, !7
A, 2
+, de03, θ7 5 Koji, /63
,oo io 291g0ko,3
θ </ , 79. Ko0ko,,2.2
</gθ, ri0.2. /, 2 < / 11.2
．． 76haq7/lIA,/'/,9
0/Daku, q@/
,g3/,,t I79.9' plate
-〇(α to Ou) Da, S to 3 7 de, ri0 da, 0
2 10 2:1. i″, ?, A
A, 2 2'1.3'3,
/-6,52&,A.

Ko, 94/30.26
The present inventors have studied methods for producing this crystalline vanadium-phosphorus oxide catalyst, and BOrdθB has the best catalytic activity.

P, 0ourtine, etc. claim (vo), p,
It was confirmed that o. And this (VO), P
,0. As a result of further study on the manufacturing method of (vo) Qp, o.

The X-ray diffraction pattern completely matches that of the original, and the purity is 100%.
% crystalline oxide. On the other hand, when a catalyst is produced by the method shown in Japanese Patent Publication No. 3-39,037, an oxide solid having a low crystal purity and having various unidentified diffraction peaks is usually obtained.

Subsequently, the present inventors investigated a method of converting a catalyst containing (vo) and p2o as active phases into a molded body with high mechanical strength and higher activity, and using the molded body 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 indispensable especially for producing spherical particle catalysts used in fluidized bed reactions (JP-A-Shoj-7, 2, 2, ? + 4'), 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 has the X-ray diffraction peaks shown in Table 1 below. A composition in which a crystalline composite oxide and silica are uniformly dispersed, wherein (1) the content of the crystalline composite oxide is 75 to 10% by weight, and (11) the ratio of phosphorus atoms to vanadium atoms. ga o, t
r~/, &, GiD The pore volume in the range of pore radius 37~2000^ is 0.0/~0.3 m1yQl, and ψ
A hydrocarbon having a carbon number of Da or more, characterized in that the pore volume with a pore radius in the range of IOθ to 3SO^ is at least -7% of the pore volume with a pore radius of 37 to 2θ00 an oxidation catalyst composition suitable for producing maleic anhydride by oxidizing
The main points are as follows.

Table - X-ray diffraction spectrum of crystalline vanadium phosphate (2θ=lθ~37 pieces/da, 2″w A, -g15.7°
Lol! ,/J/L! ″
w'1. Kude,
23.0° vs 3. g7
2g, lI” vs ,?
, /, 77.30.0” m
2.9g: 133.7″m, 2.
4! ;33A, g”m
2.1 (W means weak, vs means very strong, and m means medium heak strength) The present invention will be explained in more detail below.

In the present invention, the first component is a crystal containing substantially tetravalent nonadium and five phosphorus, which exhibits specific X-ray diffraction peaks, that is, the main X-ray diffraction peaks shown in Table 1 above. using a composite oxide. This compound is known as mentioned above, and usually first the above precursor is produced. 11- The method for producing the precursor is as follows: A solution containing tetravalent vanadium ions is prepared by reducing five vanadiums using a reducing agent such as oxalic acid, and reacting with phosphoric acid to produce a soluble vanadium-phosphorus complex. of,
Method of adding water to precipitate (%Kaishoj/-9!; 9?θ
■ Five vanadium compounds such as vanadium pentoxide and phosphoric acid are reacted in an aqueous medium in the presence of a reducing agent such as hydrazine hydrochloride or hydroxylamine hydrochloride, and then concentrated or evaporated to dryness. How to get crystals by
% Kaisho jrA-'l! ;g/! However, there is still a method in which vanadium pentoxide is reduced in an organic medium such as ethanol, isopropanol, or glycerol, reacted with phosphoric anhydride, and azeotropically dehydrated with a solvent such as benzene to precipitate crystals ( U.S. Patent No. '1.2g, ?, 2g No. 1)
, etc. are known.

A precursor of the composite oxide, which is the first component, can be obtained by any of the above methods.

12- This precursor exhibits the main X-ray diffraction peaks shown in Table-3 below.

Table-3 Main X-ray diffraction peaks of the precursor of the first component/! r, 7@/
θO 19,6° 5O 241,2° lI.

, 2? , 10IIs Koza, g" 23 30, 'l' KO In the present invention, it is necessary that the crystalline phosphorus-vanadium composite oxide, which is the first component, has substantially 100% purity. Therefore, it is necessary to produce a precursor having substantially 100% purity.For this purpose, it is preferable to produce the precursor by the method shown below. It is produced by dissolving vanadium pentoxide in an aqueous medium to form a homogeneous solution in the presence of .

As the inorganic reducing agent, hydrazine (usually commercially available as an aqueous solution of hydrazine hydrate) or its phosphate, and hydroxylamine or its phosphate are preferred.

Other inorganic acid salts, such as hydrochloride salts, can also be used, but since they leave halogen ions behind, they are disadvantageous in terms of the reactor material and are not preferred industrially.

Water is generally used as the aqueous medium.

If desired, hydrophilic organic solvents such as dialcohols, carboxylic acids, ethers, and ketones may be used in combination, but the reduction rate of vanadium will be reduced, so the amount used should be 50% by weight.
The amount of phosphoric acid used should be as follows:
The atomic ratio is /, but it is usually preferable to add in the range of 0.1 to 7.5. The concentration of phosphoric acid in the aqueous medium is j-10
% by weight, preferably j--4'j % by weight. If the concentration of phosphoric acid in the aqueous medium is too high, there is a possibility that vanadium pentoxide will react with the phosphoric acid before it is reduced, and the viscosity of the liquid will also become extremely high, making it difficult to handle. Furthermore, 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 a stoichiometric amount sufficient to reduce five vanadiums to tetravalent ones, and usually 9S~
The solution obtained in the above manner used in the range of 720% is then heated to 10°C to 70°C, preferably 7°C, in a substantially sealed container to prevent evaporation of water. The hydrothermal treatment is carried out at a temperature in the range of .20°C to /gO°C. Hydrothermal treatment is performed at θ1. It is preferable to carry out the process for about t-20θ 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-phosphorous crystalline oxide precursor, and can be obtained by evaporating the slurry to dryness or directly filtering it from the slurry. By this method, a crystalline oxide with a fine particle size can be obtained.An activity promoting component may be added to the first component of the present invention.

Active ingredients include iron, chromium, aluminum, titanium, calcium, magnesium, manganese, cobalt,
Examples include metals such as nickel. An example of a method for introducing these metals into the first component is to add these compounds to the above solution. Such compounds include particularly limited acid salts as long as they are soluble in the above-mentioned solutions. In the case of titanium, the use of peroxides is also possible. The timing of addition is preferably before hydrothermal treatment.

The amount added is 0.0 as metal per mole of vanadium element.
It should be adjusted to a range of /~o, trt mol, more preferably 0.0.2~O,S mol.

The above-mentioned metal component may be one kind or a mixture of two or more kinds.

When such an activity-promoting component is added, X of the precursor and the first component of the crystalline composite oxide obtained is
The position of the line diffraction spectrum may shift slightly, but the range is within 101.2 degrees (JP-A-56-Otsu No. 9,207, JP-A-Sho!r7-///, No. 21g) reference)
.

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 1, but in the end, it will remain unfired and become a dry powder containing silica etc. It may also be 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 axial pores, and among these pores, the pore radius is 37. The pore volume in the range of 200θ^ is 0.
0 / ~I! ;1. ．． ? mVg, preferably O1θ
3 to 0, 3 m//9 and its pore volume is 3
It is necessary that 0% or more of the pores be occupied by pores with a pore radius in the range of 700 to 330λ. Pore 16 - Capacity is measured by a commonly used mercury intrusion 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 1
The presence of a certain amount or more of pores with a pore volume in the range of 00 to 3Sθ^ is required, but if there are many pores with a radius in the range of ioo to 3SOλ, the so-called mesopore range, the catalytic activity is improved, and for example, in the final catalyst composition. Even when the active component, which is the first component, is contained at most about 33%, a highly active catalyst equivalent to that obtained using the active component 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 as 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 an amorphous vanadium-phosphorus composite oxide, but in the catalyst production stage an aqueous solution containing vanadium and phosphorus is used, which is essentially tetravalent vanadium and pentavalent vanadium. It is preferred that at least a portion of the phosphorus is present as vanadyl phosphate.Next, a method for producing the aqueous solution as the second component will be described.

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 O,S to 10. Generally, an aqueous solution containing vanadyl phosphate is unstable and it may be difficult to keep it stable for a long time, but oxalic acid can be present to stabilize the aqueous solution. The amount thereof is in the range of 01λ to 100% by molar ratio of oxalic acid to vanadium. 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 less than or equal to 50% 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 so that the molar ratio of oxalic acid to vanadium is less than or equal to Huff, and preferably more than 0, q. An aqueous solution containing an acid. 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 υ reduction proceeds by slight heating. According to this method, after completion of the reduction, less than hecomoles of oxalic acid will be present per 7 moles of vanadium atoms.

First, in an acidic aqueous solution containing phosphoric acid, a reducing agent other than oxalic acid, preferably hydrazine hydrate, or an inorganic reducing agent such as hydrazine or hydroxylamine hydrochloride or phosphate, lactic acid = 19- One or a mixture of two or more organic reducing agents selected from the following are added, and then vanadium pentoxide is added for reduction to obtain a homogeneous aqueous solution containing vanadyl phosphate. After this,
Preferably oxalic acid is 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 1 below precipitates.

Table - (α on anticathode Cu) 20 - Precipitation of such crystalline solids is not preferred from the purpose of the present invention, and if it is necessary to keep the aqueous solution stable for a long time, oxalic acid should be added. is preferable.

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 crystalline composite oxide of the first component. Although it has significantly lower activity than oxides, it has a large effect of dispersing the first component into the catalyst composition, and is particularly effective in masking micropores with a pore radius of 10A or less that are harmful to selective oxidation catalysts. The activity of the entire catalyst can be improved.

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 kind of silica can be used, it is particularly preferable to use silica sol to form a spherical catalyst suitable for fluidized bed reactions. The spherical catalyst is formed by spray drying a slurry of the first, second and third components under controlled conditions. Regarding the usage amounts of the first component, second component and third component,
The first component should be present in the final catalyst composition in an amount of 15-10% by weight, preferably 20-60%.

The first component is an active component, and if this amount is less than 15% by weight, there will be a problem in terms of catalytic activity, and even if it exceeds the gO weight ratio, the activity will not improve, and on the contrary, the catalytic strength will increase. 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, but usually the dry weight ratio of the first component:
Second component: Third component / : 0. /~7:0. OAr
~g, preferably /: 0.5 ~ tick 〇, s ~ ko range.

Further, it is necessary that the P/V of the entire catalyst be in the range of o, g to /, 51, more preferably /, 1 to /, 3. The P/V of the first component is essentially / and the total P / Balance the V. If this atomic ratio is smaller than 0.1, it will cause problems in terms of catalyst selectivity, and /, r
If it is too large, it is 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 may be dried and pulverized before being made into a slurry, or it may be spray-dried after the precursor is produced by hydrothermal treatment. may be mixed with the second and third components. Also, before mixing, air (may contain butane or butenes in some cases) at a temperature range of 300 to 700°C.
It can also be used by firing in the presence of 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.

23- The first component, second component, and third component are mixed to a desired amount of active ingredients, preferably using a continuous wet grinder or the like to form a sufficiently homogeneous sludge, and then spray-dried. Then, it is baked.

Compounds such as iron, chromium, aluminum, titanium, calcium, magnesium, manganese, cobalt, nickel, etc. may be added at the stage of catalyst preparation, that is, at the stage of mixing the first component, second component, and third component. These compounds may be included in the first component as described above, or
It may be added to the catalyst preparation stage or both. The amount of the metal compound added in the catalyst preparation step is preferably in the range of 0.000 to 0.2 moles per mole of vanadium atoms.

Spray drying conditions are important in controlling the pores of the final catalyst. It is well known to those skilled in the art that the physical properties of the catalyst are affected by the spray drying conditions, such as the model, amount of liquid supplied, amount of drying gas, temperature, etc., and the optimum conditions may vary depending on the properties of the specific slurry. It is necessary to find out. Typically, the oxide concentration in the 24-slurry is on the order of io-go%, and the dry concentration in the spray dryer chamber is io-go%.

It is best to select from the range of ~20θ℃, and more preferably, the slurry with an oxide concentration of 770~13% is /&-4'.
It is preferable to process at a drying temperature of 0°C.

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 as follows: There is no particular difference in the firing conditions. By the above method, the average particle size 3θ~iooμm1, preferably 110~708m1, the specific surface area O,S~-20t
r? A catalyst composition containing substantially spherical particles of /I 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 will be inconvenient in terms of activity, and if the specific surface area is too large, the selectivity of maleic anhydride will decrease. Therefore, 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
It has an activity equal to or greater than that when the first component is used alone, and is extremely effective as a catalyst for fixed bed reactions.

The catalyst of the present invention can be effectively used for producing maleic anhydride by oxidizing hydrocarbons having carbon atoms of Da or more. As the hydrocarbon, n-butane, n-butene, isobutyne, bucdiene, etc. can be used alone or in combination.As described above, according to the present invention, a hydrocarbon having a number of grams or more of carbon atoms is oxidized to form maleic anhydride. A highly active, high strength catalyst composition suitable for producing is provided.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example-/(Production of highly pure active ingredient precursor) A crystalline active ingredient precursor exhibiting the X-ray diffraction peaks shown in Table 3 was produced in the following manner. 3 g of demineralized water, OK9, l in a jacketed pressure-resistant container with a 1-oot glass lining.
rr% phosphoric acid comb g3Kg, go% hydrazine hydrate bath liquid, g! Kg was charged, and then vanadium pentoxide powder/l, '1 OK9 was added and dissolved little by little while stirring, being careful not to foam. During this time, in order to suppress the temperature rise due to heat generation and maintain the liquid temperature at AO-fO°C, a heating medium was circulated within the jacket to remove heat. Addition of vanadium pentoxide was completed in about 10 hours to obtain a blue vanadyl phosphate solution. A seed crystal of 1,000 kg was added to this, and then a heating medium of 1,0°C was circulated inside the jacket to heat it. Liquid temperature/up to 410″C2
The temperature was raised over time, and hydrothermal treatment was performed for 10 hours. During this time, the pressure is approximately 0.2'I MPa (gauge pressure)
Met.

After cooling to 90"C, 70.3 kg of demineralized water was added to adjust the solid concentration in the slurry to approximately 3596, and the slurry was extracted. When X-ray diffraction measurements were performed on this solid, the results shown in Table-
It was found that it exhibited the main diffraction peak shown in No. 3, 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 investigated using a counter method, it was found that the average particle size was θ, 7 μm. This oxide slurry was dried using a spray dryer to obtain a pale blue powder of oxide: t9. gKg was obtained. The standard P/V atomic ratio of the oxide slurry is /, 0! ; However, the crystalline precursor solid obtained by filtration and washing is substantially (VzO<
) (PaOi) (2H2'').

Example 2 (Production of highly pure active ingredient) The active ingredient precursor obtained in Example 7 was fired to produce a crystalline oxide having the X-ray diffraction pattern shown in Table 2. i.e. 5oot
In a Matsufuru furnace with a capacity of 2, 10 kg of the precursor obtained in Example 1 was divided into 70 porcelain vessels with a capacity of 2, and arranged in batches, and after the inside of the furnace was sufficiently replaced with nitrogen gas, the temperature was raised. , SSO at 2
heated for an hour. Next, air -28= was gradually introduced into the furnace, and the mixture was heated for a further 7 hours, and then allowed to cool.

As a result of xi diffraction, the powder after firing did not show any peaks other than the first diffraction peak shown in Table C, 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 1.2.7.4 (%. That is, (vc')s"i
At least a part of the vanadium in Oy can absorb oxygen and take a pentavalent state while maintaining its crystal structure.

Example 3 (Manufacture of vanadium phosphate solution) A vanadium phosphate solution was manufactured as an example of a suitable raw material for a composite oxide containing amorphous phosphorus and vanadium as main constituent elements. gs
% of phosphoric acid was dissolved in demineralized water of 3.0% to 3.0%, and oxalic acid (H2C204.yu,o)s,zs was added and dissolved by heating. The solution was heated to .go.degree. C., and vanadium pentoxide was added little by little while being careful not to form bubbles. After dissolving the solution, the solution was further heated at boiling for 70 minutes to complete the reduction. Let the liquid cool and add demineralized water to bring the total volume to 10
．． The weight was adjusted to 00Kg. The P/V atomic ratio of this solution is /,
, 2A/&, oxide (V204+ P2O,) concentration is 3
! r, Oq6.

Example-1I (Production of catalyst-/) Precursor dry powder obtained in Example-//393. A I, vanadium phosphate solution obtained in Example-3/, 9 to I'13, and commercially available colloidal silica solution A2 with lIO% concentration.
A solution prepared by diluting J,/g with demineralized water, glIKg, was mixed and then processed in a continuous wet grinder to be thoroughly homogenized. This slurry was dried using a spray dryer to obtain spherical catalyst particles with an average particle diameter of Sgμm. This is 330
C. for 7 hours under an air stream, and then at SOO DEG C. for 1 hour under a nitrogen stream to obtain a catalyst.

Example-5 (Production of catalyst-U) Calcined powder 3 obtained in Example-1! , 3. ．． A catalyst was prepared in exactly the same manner as in Example 1 except that No. 21 was used instead of the dry precursor powder.

Example-6 (Manufacture of catalyst-3) Calcined powder 3S3. obtained in Example-6. P/V atomic ratio /, / A O, oxidation -3 obtained in the same manner as Example 3
1= Vanadium phosphate solution with a concentration of 0/! G? , 1Il
i, and a commercially available 2θ% colloidal silica solution, 2
//9.2Fl was mixed and then processed in a continuous wet mill to ensure thorough homogenization. This slurry having an oxide concentration of 33% was dried using a spray dryer at a drying temperature of 30° C. to obtain true spherical catalyst particles having an average particle diameter of 67 μm. This is 5oo
The catalyst was calcined under a nitrogen stream for one hour at c. to give catalyst-3.

Example-I (manufacture of catalyst) Calcined powder 73011 obtained in the same manner as in Example-C, P/'vJ ratio/, A 97, obtained in the same manner as in Example-3,
Oxide concentration 3'1. ! r% vanadium phosphate solution 1
0009 and a commercially available qo% colloidal silica solution 10/2, Sg, demineralized water/3, 9 were mixed and then processed in a continuous wet mill to thoroughly homogenize. Add 3.27 to 7 of water to this slurry to reduce the oxide concentration to 2.
After diluting to 0%, drying temperature /, 3 using a spray dryer.
It was dried at 0° C. to obtain true spherical catalyst particles with an average particle diameter of μm. This powder was dried overnight in a drier at SOO°C, and then calcined at SOO°C for 3 hours under a nitrogen stream to obtain a catalyst.

Comparative Example-/(Manufacture of Comparative Catalyst-/) The vanadium phosphate solution obtained in Example-3 was prepared in colloidal form with a concentration of 11.3 Kf and 4 tO2 without using the calcined powder obtained in Example-A. Silica solution box left chest, desalinated water box 3.2K
g were mixed and spray-dried to obtain spherical catalyst particles having an average particle diameter of 56 μm, and calcined in the same manner as in Example 1 to obtain a comparative catalyst.

Comparative Examples Co-S (Production of Comparative Catalyst-1 to S) The calcined powder obtained in Example-1, the vanadium phosphate solution obtained in Example-3, and the colloidal silica solution are shown in Table-5. They were mixed in various proportions and spray-dried to obtain spherical catalyst particles, which were then calcined in the same manner as in Example D to obtain Comparative Catalysts 1 to S.

The manufacturing method, composition, and physical property measurement results of the catalyst are shown in Table-32- Reaction Example-/ Using a 3% n-butane-air mixed gas, a small fluidized bed reactor made of hard glass, the catalyst shown in Table-7, 2O- 1GH8
Activity tests were performed at V j 00. The reaction products were collected in water and quantitatively analyzed by potentiometric titration of the extract and gas chromatography of the waste gas. The results are shown in Table-7.

Table-7 Activity test results Reaction example-2 Catalyst = 2, catalyst-g and comparative catalyst-λ, and working example-
Grind each of the baked powders with a mortar and use a tablet molding machine to
After molding to wnp X 3 mH, crush it and
, 24' mesh particles were sieved. Fill a hard glass microreactor with the mixture and add n-butane to a mixed gas of 5%/air, GH8V.
, 2θθO. The products were analyzed by gas chromatography. The results of comparing catalyst performance are shown in Table-g. Catalyst-1 <z shows the same results as the calcined powder of Example-Y.

Table-g Reaction Example-3 A mixed gas of 1-butene, imbutylene, /, 3-butadiene and /-butene-n-butane was produced by a fluidized bed reaction in the same manner as in Reaction Example 7 using a catalyst. I continued to react.

Hydrocarbon concentration is 3% each, GH8V! ; Set to 0θ. The reaction results are shown in Table-9.

Table 9 Reaction Example Dani 0rnet catalyst-1 was packed into the small fluidized bed reactor used in Reaction Example-/, and 3% n-butane, /-butene o,
A mixed gas of g% and air was introduced to react. GH8
V! 0 '0, reaction temperature titio ℃, n-butane conversion rate g7.3%, /-butene conversion rate tooq6, the maleic anhydride yield based on the total hydrocarbons is 1
It was 1.5-, A%.

Patent applicant: Mitsubishi Chemical Industries, Ltd.

Claims (1)

[Scope of Claims] (1) A composition in which a crystalline composite oxide containing vanadium and phosphorus and exhibiting the X-ray diffraction peaks shown in the table below and silica are uniformly dispersed, comprising: The content of oxide is 15~go weight ratio, (11) the ratio of phosphorus atoms to vanadium atoms is θ1g
~7.5, 011) Pore radius 37~: The pore volume in the range of 1000 is 0.0/~0.3 mV9, and (φ) The pore volume in the range 100~3S0λ is Pore capacity is pore radius 3
The pore volume is 50 or more in the range of 7 to 000. An oxidation catalyst composition suitable for producing maleic anhydride by oxidizing a hydrocarbon having a carbon number of Da or more. X-ray diffraction peak (α to anticathode Ou-) /da, -〇/,! i, 7°/gJ" C3.O0,2g,lI. 30.0" 33.7°3 A,g' (2. The pore volume in the radius range of 37 to 2000λ is θ, 03 to o, 3ml/11. (3) The oxidation catalyst composition according to claim 7 or 1. (4) comprising (a) the crystalline composite oxide, (b) an amorphous composite oxide containing vanadium and phosphorus, and (C) silica, which are uniformly dispersed. (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=/
:0. / 〜ri', o, os〜+.