JP4185404B2 - Catalyst for producing unsaturated aldehyde and unsaturated carboxylic acid, method for producing the same, and method for producing unsaturated aldehyde and unsaturated carboxylic acid - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a catalyst for producing an unsaturated aldehyde and an unsaturated carboxylic acid, a method for producing the same, and a method for producing an unsaturated aldehyde and an unsaturated carboxylic acid. Specifically, the present invention stabilizes the corresponding unsaturated aldehyde and unsaturated carboxylic acid in high yield and long-term by gas phase oxidation of at least one compound selected from propylene, isobutylene, t-butanol and methyl-t-butyl ether. The improved catalyst for the production of the catalyst, the process for producing the catalyst, and at least one compound selected from propylene, isobutylene, t-butanol and methyl-t-butyl ether using the catalyst, and correspondingly The present invention relates to a method for producing unsaturated aldehydes and unsaturated carboxylic acids.
[0002]
[Prior art]
Various improved catalysts have been proposed for the efficient production of the corresponding unsaturated aldehydes and unsaturated carboxylic acids by gas phase catalytic oxidation of propylene, isobutylene, t-butanol or methyl-t-butyl ether. Most of the proposed catalysts are based on molybdenum, bismuth and iron.
[0003]
However, these catalysts still have problems to be improved in terms of yield and lifetime of unsaturated aldehydes and unsaturated carboxylic acids. Molybdenum in the catalyst is easily scattered, which causes irreversible deterioration of the catalytic activity. The oxidation reaction is a very exothermic reaction, and molybdenum is remarkably scattered in the catalyst layer, particularly in a locally abnormal high temperature zone called a hot spot. In particular, in a high load operation for the purpose of high productivity, the heat storage in the hot spot portion is naturally larger, so the period of using the catalyst at a high temperature becomes longer. Considering these things, there is a demand for a catalyst that exhibits high activity and stable performance over a long period of time. Also, this type of catalyst is generally prepared as a molding catalyst by granulation method, extrusion molding method, etc., but various catalyst physical properties (pore volume, pore size distribution, specific surface area) must be prepared with good reproducibility. In addition, it has a mechanical strength (abrasion resistance) that can withstand impacts such as when the catalyst is charged and does not cause reaction tube blockage and reaction pressure increase due to catalyst powder that has been peeled off when the catalyst is subjected to a long-term reaction. ) Is also required.
[0004]
Many methods have been proposed for the production of unsaturated aldehyde and unsaturated carboxylic acid production catalysts (see, for example, Patent Documents 1 to 4). In addition, a method has also been proposed in which a composite oxide catalyst whose performance is deteriorated by use in a reaction is used in combination with an unused composite oxide catalyst in the reaction (see Patent Document 5).
[Patent Document 1]
Japanese Patent Laid-Open No. 8-24652
[Patent Document 2]
JP-A-5-253480
[Patent Document 3]
Japanese Patent Laid-Open No. 9-10588
[Patent Document 4]
JP 2002-273228 A
[Patent Document 5]
JP-A-9-12489
[0005]
However, even these catalysts do not have industrially sufficient performance, and from an industrial standpoint, machines that enable stable operation over a long period of time even in high-load operation aimed at high productivity. Development of an excellent catalyst for producing unsaturated aldehydes and unsaturated carboxylic acids is desired.
[0006]
[Problems to be solved by the invention]
One of the objects of the present invention is to produce the corresponding unsaturated aldehyde and unsaturated carboxylic acid in high yield by vapor phase oxidation of at least one compound selected from propylene, isobutylene, t-butanol and methyl-t-butyl ether. It is an object of the present invention to provide an unsaturated aldehyde and unsaturated carboxylic acid production catalyst and a production method thereof.
[0007]
Another object of the present invention is to provide an unsaturated aldehyde and unsaturated carboxylic acid production catalyst having excellent mechanical strength, which has a long catalyst life and enables stable operation over a long period of time, and a method for producing the same. is there.
[0008]
Still another object of the present invention is to provide an unsaturated aldehyde and unsaturated carboxylic acid production catalyst excellent in mechanical strength that enables stable operation over a long period of time even in high-load operation aimed at high productivity. And providing a method for producing the same.
[0009]
Still another object of the present invention is to provide a method for producing an unsaturated aldehyde and an unsaturated carboxylic acid stably in a high yield and over a long period of time using the above catalyst.
[0010]
[Means for Solving the Problems]
The inventors of the present invention, when producing a conventionally known catalyst containing molybdenum, bismuth and iron as essential components as an unsaturated aldehyde and unsaturated carboxylic acid production catalyst, are mixed with a part of the raw material compound, dried, Firing to produce a primary finished catalyst, then using this primary finished catalyst as it is in a solid state, mixing it with the remaining raw material compounds, drying and calcining to give a finished catalyst, the physical properties of this catalyst are reproducible In addition to being obtained well, this catalyst showed high activity in the above reaction and was excellent in stability, and it was found that the above object can be achieved when this catalyst is used as a catalyst in the above reaction.
[0011]
  That is, the present invention
(1) Gas phase oxidation of at least one compound selected from propylene, isobutylene, t-butanol and methyl-t-butyl ether using molecular oxygen or a molecular oxygen-containing gas, and corresponding unsaturated aldehydes and unsaturated carboxylic acids For producing acidGeneral formula (1):
MoaWbBicFedAeBfCgDhEiOx (1)
(Where Mo is molybdenum, W is tungsten, Bi is bismuth, Fe is iron, A is at least one element selected from nickel and cobalt, B is at least one element selected from alkali metals and thallium, and C is an alkali. At least one element selected from earth metals, D is at least one element selected from phosphorus, tellurium, antimony, tin, lead, niobium, manganese, arsenic and zinc, E is at least one selected from silicon, aluminum and titanium And O represents oxygen, and a, b, c, d, e, f, g, h, i, and x represent Mo, W, Bi, Fe, A, B, C, D, E, and Represents an atomic ratio of O, and when a is 12, b is 0 to 10, c is 0.1 to 10, d is 0.1 to 20, e is 2 to 20, and f is 0.001. 10, g is 0, h is 0 to 4, i is 0 to 30, x is a numerical value determined by the oxidation state of each element)
Represented byA catalyst,Includes all elements of the constituent elements of the finished catalystAfter mixing a part of the raw material compound, drying and calcining to produce a primary finished catalyst,Has not passed a heat history of 200 ° C or higherAfter mixing with the remaining raw material compounds, it was obtained by drying and firing.The primary finished catalyst is contained in a proportion of 1 to 30% with respect to the total mass of the finished catalyst.A catalyst for producing an unsaturated aldehyde and an unsaturated carboxylic acid,
(2)The unsaturated aldehyde and unsaturated carboxylic acid production catalyst according to the above (1), which is calcined at 300 to 600 ° C. (excluding 600 ° C.) to produce a primary finished catalyst,
(3) Gas phase oxidation of at least one compound selected from propylene, isobutylene, t-butanol and methyl-t-butyl ether using molecular oxygen or a molecular oxygen-containing gas, and corresponding unsaturated aldehydes and unsaturated carboxylic acids In producing the acid, the above (1) is used as a catalyst.Or (2)A method for producing an unsaturated aldehyde and an unsaturated carboxylic acid, characterized by using a catalyst of
It is.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The composition of the catalyst of the present invention may be any as long as it contains molybdenum, bismuth and iron as essential components and is generally known for use in the production of unsaturated aldehydes and unsaturated carboxylic acids. As a typical example of the catalyst of the present invention, a catalyst represented by the general formula (1) can be mentioned.
[0013]
A feature of the present invention is that a part of the raw material compound is mixed, dried and calcined to produce an oxide (in the present invention, this is referred to as a primary completed catalyst), and then this primary completed catalyst and The remaining raw material compound is mixed and then dried and calcined to obtain a finished catalyst.
[0014]
The “raw material compound” for producing the primary finished catalyst is a raw material compound containing at least one element of constituent elements of the finished catalyst, preferably a raw material compound containing each element of molybdenum, bismuth and iron, more preferably This means a part of the raw material compound containing all the constituent elements of the finished catalyst. The “part” can be appropriately determined such that the ratio of the primary completed catalyst to the completed catalyst is 1 to 30 mass%, preferably 2 to 20 mass%, based on the mass of the completed catalyst. If the amount of the primary finished catalyst is too small, the effect of adding the primary finished catalyst cannot be obtained. On the other hand, if the amount is too large, a decrease in yield is observed, and the amount of unsaturated aldehyde and unsaturated carboxylic acid produced as the target product is reduced. , CO₂And the amount of CO produced increases.
[0015]
The “remaining raw material compound” to be mixed with the primary finished catalyst means a raw material compound necessary for producing the intended finished catalyst in combination with the primary finished catalyst. It can be easily determined based on the composition and composition ratio of the finished catalyst and the primary finished catalyst.
[0016]
There is no restriction | limiting in particular in the kind of raw material compound, Any can be used if it is an oxide containing each element, or a compound which produces | generates an oxide by baking. Examples of the compound that generates an oxide by firing include a hydroxide, a metal acid, a nitrate, a carbonate, an ammonium salt, an acetate, and a formate. A compound containing two or more elements can also be used. For example, specific examples of the molybdenum-containing compound include molybdenum trioxide, ammonium paramolybdate, molybdic acid, and phosphomolybdic acid.
[0017]
The primary completed catalyst is prepared by, for example, dissolving a part of the raw material compound in an aqueous medium as appropriate, heating and stirring, drying by evaporation to dryness, further pulverizing and molding as necessary, and then under air flow. It is obtained by baking at a temperature of 300 to 600 ° C., preferably 350 to 550 ° C. for 1 to 10 hours, preferably about 2 to 8 hours.
[0018]
The primary finished catalyst thus obtained is mixed with the remaining raw material compounds, and then dried and calcined to produce the intended finished catalyst. The form of the “remaining raw material compound” is not particularly limited, and may be in the form of a solution or slurry obtained by dissolving or suspending the remaining raw material compound in an aqueous medium, or by evaporating this solution or slurry to dryness. It may be in a dry form. Therefore, the catalyst of the present invention can be produced, for example, according to the following two aspects.
(1) The remaining raw material compound is dissolved or slurried in an aqueous medium, and this is mixed with a primary finished catalyst, usually a primary finished catalyst, which is appropriately pulverized, and dried. The firing is preferably performed at a temperature of 350 to 550 ° C. for 1 to 10 hours, preferably about 2 to 8 hours.
(2) The remaining raw material compound is dissolved or slurried in an aqueous medium, and then this is dried at a temperature of less than 200 ° C., preferably 150 to 180 ° C., and the resulting dried product is pulverized as a primary finished catalyst, usually appropriately. The mixture is mixed with a powdery primary finished catalyst, and then calcined under air flow at a temperature of 300 to 600 ° C., preferably 350 to 550 ° C. for 1 to 10 hours, preferably about 2 to 8 hours.
[0019]
As described above, in the production of the catalyst of the present invention, it is preferable that the remaining raw material compounds do not pass through a thermal history of 200 ° C. or higher before mixing with the primary finished catalyst. Heating to a temperature of 200 ° C. or higher is not preferable because the scattered components derived from the raw material compounds in the dried product will be burned out too much.
[0020]
The catalyst of the present invention may be used alone or may be used by being supported on an inert support such as alumina, silica-alumina, silicon carbide, titania, magnesia, aluminum sponge and the like. In addition, inorganic fibers such as glass fibers and various whiskers that are generally well-known as having an effect of improving the strength and the degree of pulverization of the catalyst may be added. Furthermore, in order to control the physical properties of the catalyst with good reproducibility, additives generally known as powder binders such as ammonium nitrate, cellulose, starch, polyvinyl alcohol, stearic acid and the like can be used.
[0021]
There is no restriction | limiting in particular about the shape of a catalyst, It can be set as arbitrary shapes, such as a pellet form, spherical shape, a column shape, a ring shape, and a tablet shape. For example, in the case of a spherical shape, the average diameter is usually 1 to 15 mm, preferably 3 to 10 mm.
[0022]
The production of unsaturated aldehydes and unsaturated carboxylic acids according to the present invention is propylene, isobutylene, t-butanol or methyl-t-butyl ether, or a mixture of two or more thereof, except that the catalyst of the present invention is used as a catalyst. Can be carried out under the conditions generally used or known to be used in the production of the corresponding unsaturated aldehyde and unsaturated carboxylic acid by gas phase oxidation reaction. For example, 1 to 10% by volume, preferably 2 to 8% by volume of at least one raw material compound selected from propylene, isobutylene, t-butanol and methyl-t-butyl ether, 1 to 10 times the raw material compound in a volume ratio, Preferably molecular oxygen in the range of 1 to 8 times, or such molecular oxygen and inert gas as diluent, such as nitrogen, carbon dioxide gas, water vapor (especially the use of water vapor suppresses the formation of by-products. Etc.) in a temperature range of 250 to 450 ° C., preferably 280 to 420 ° C., normal pressure to 1 MPa, preferably 300 to 5 at normal pressure. , 000 hr^-1(STP), preferably 500 to 4,000 hr^-1What is necessary is just to make it contact with the catalyst of this invention with the space velocity of (STP).
[0023]
According to the method of the present invention, propylene to acrolein and acrylic acid, isobutylene to methacrolein and methacrylic acid, t-butanol to methacrolein and methacrylic acid, and methyl-t-butyl ether to methacrolein and methacrylic acid, Each is obtained. Of course, by appropriately changing the reaction conditions, it is possible to variously change the production ratio of unsaturated aldehyde and unsaturated carboxylic acid. For example, if propylene is a starting compound, acrolein is the dominant component, A mixture containing acrylic acid as an inferior component can be obtained as a product.
[0024]
【The invention's effect】
By using the catalyst of the present invention, the corresponding unsaturated aldehyde and unsaturated carboxylic acid can be obtained in a high yield by gas phase oxidation of at least one compound obtained from propylene, isobutylene, t-butanol and methyl-t-butyl ether. Can be manufactured.
[0025]
Moreover, since the catalyst of the present invention has a long catalyst life, it can be stably operated over a long period of time.
Furthermore, the catalyst of the present invention enables a stable operation over a long period even in a high load operation aiming at high productivity.
[0026]
【Example】
  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further more concretely, this invention is not limited by these Examples. The conversion rate, selectivity, and single flow yield are defined as follows.
Conversion rate (%) = {(number of moles of reacted raw material compound) / (number of moles of supplied raw material compound)} (× 100)
Total selectivity (%) = {(total number of moles of unsaturated aldehyde and unsaturated carboxylic acid produced) / (number of moles of reacted raw material compound)} (× 100)
Total single flow yield (%) = {(total number of moles of unsaturated aldehyde and unsaturated carboxylic acid produced) / (number of moles of supplied raw material compound)} (× 100)
Example 1
(Preparation of catalyst)
  To 2 liters of ion-exchanged water, 1500 g of ammonium paramolybdate and 382.4 g of ammonium paratungstate were added and dissolved while stirring. Separately, 1648.5 g of cobalt nitrate, 429.1 g of ferric nitrate and 69.0 g of cesium nitrate were dissolved in 1 liter of ion-exchanged water. Also, 515.2 g of bismuth nitrate was dissolved in an aqueous nitric acid solution consisting of 300 ml of ion-exchanged water and 50 ml of concentrated nitric acid. These two aqueous solutions were picked and mixed in the separately prepared aqueous solution, and then 212.7 g of silica sol having a concentration of 20% by mass was added and mixed to obtain a slurry (slurry A).
  Separately, 75 g of ammonium paramolybdate and 19.1 g of ammonium paratungstate were added to 100 ml of ion-exchanged water heated and dissolved while stirring. Separately, 82.4 g of cobalt nitrate, 21.5 g of ferric nitrate and 3.5 g of cesium nitrate were dissolved in 50 ml of ion-exchanged water. Further, 25.8 g of bismuth nitrate was dissolved in an aqueous nitric acid solution consisting of 15 ml of ion-exchanged water and 2.5 ml of concentrated nitric acid. These two aqueous solutions were dropped into the separately prepared aqueous solution and mixed, and then 10.6 g of silica sol having a concentration of 20% by mass was added and mixed. The slurry thus obtained was heated and stirred, evaporated to dryness, water was added as a molding aid, molded into pellets having an outer diameter of 6 mm and a length of 6.6 mm, dried, and 500 ° C. under air flow. Was calcined for 6 hours to obtain a primary completed catalyst (catalyst B).
  The obtained catalyst B was pulverized, added to the slurry A, mixed, evaporated to dryness, and pulverized. Water was added thereto as a molding aid, molded into pellets having an outer diameter of 6 mm and a length of 6.6 mm, dried, and then calcined at 500 ° C. for 6 hours in an air stream to obtain a catalyst (1). The elemental composition of the catalyst (1) was as follows in terms of atomic ratio (excluding oxygen, the same applies hereinafter).
Mo_1 2 W₂ Bi_1 . Five Fe_1 . FiveCo₈ Cs_0.5 Si₁
(Oxidation reaction)
  1200 ml of catalyst (1) was charged into a steel reactor having a diameter of 25 mm. A mixed gas having a composition of 6% by volume of isobutylene, 13% by volume of oxygen, 8% by volume of water vapor and 73% by volume of nitrogen was introduced into the reactor, and the reaction temperature was 340 ° C. and the space velocity was 1500 hr.^- 1 The oxidation reaction was performed with (STP). The results are shown in Table 1.
(Catalyst strength measurement method)
  A stainless steel reaction tube having an inner diameter of 25 mm and a length of 5000 mm was installed in the vertical direction, and the lower end of the reaction tube was covered with a stainless steel receiving plate having a thickness of 1 mm. About 50 g of the catalyst (1) was dropped into the reaction tube from the upper end of the reaction tube, the stainless steel receiving plate at the lower end of the reaction tube was removed, and the catalyst was gently extracted from the reaction tube. The extracted catalyst was sieved with a sieve having an opening of 5 mm, the mass of the catalyst remaining on the sieve was measured, and the catalyst strength was calculated by the following formula.
Catalyst strength (mass%) = {(mass of catalyst remaining on the sieve) / (mass of catalyst dropped from the upper end of the reaction tube)} × 100
Example 2
(Preparation of catalyst)
  The slurry A obtained in Example 1 was heated and stirred at 150 ° C., and most of the water was evaporated to obtain a cake-like dried product (dried product C).
  Separately from this, the primary finished catalyst B obtained in Example 1 was pulverized, added to the dried product C, mixed well, then water was added as a molding aid, and the outer diameter was 6 mm and the length was 6.6 mm. After forming into pellets and drying, the catalyst (2) was obtained by calcining at 500 ° C. for 6 hours under air flow. The elemental composition of the catalyst (2) was as follows in terms of atomic ratio.
Mo_1 2 W₂ Bi_1 . Five Fe_1 . FiveCo₈ Cs_0 . Five Si₁
(Oxidation reaction)
  In Example 1, the oxidation reaction was performed under the same reaction conditions as in Example 1 except that the catalyst (2) was used instead of the catalyst (1). The results are shown in Table 1.
(Catalyst strength measurement method)
  For the catalyst (2), the catalyst strength was measured under the same measurement conditions as in Example 1. The results are shown in Table 1.
Example 3
(Preparation of catalyst)
  A dried product C was obtained in the same manner as in Example 2.
  Separately, 75 g of ammonium paramolybdate and 9.6 g of ammonium paratungstate were added to 100 ml of heated ion-exchanged water and dissolved while stirring. Separately, 61.8 g of cobalt nitrate, 10.3 g of nickel nitrate, 21.5 g of ferric nitrate and 4.1 g of cesium nitrate were dissolved in 50 ml of ion-exchanged water. Further, 30.9 g of bismuth nitrate was dissolved in an aqueous nitric acid solution consisting of 15 ml of ion exchange water and 2.5 ml of concentrated nitric acid. These two aqueous solutions were picked and mixed in the separately prepared aqueous solution, and then 10.6 g of silica sol having a concentration of 20% by mass was added and mixed to obtain a slurry. The slurry thus obtained was heated and stirred, evaporated to dryness, water was added as a molding aid, molded into pellets having an outer diameter of 6 mm and a length of 6.6 mm, dried, and then air-circulated at 500 ° C. Was calcined for 6 hours to obtain a primary completed catalyst (catalyst D). After pulverizing the catalyst D, it is added to the dried product C and mixed well. Then, water is added as a molding aid, molded into pellets having an outer diameter of 6 mm and a length of 6.6 mm, dried, and then air-flowed at 500 ° C. And calcined for 6 hours to obtain a catalyst (3). The elemental composition of the catalyst (3) was as follows in terms of atomic ratio.
Mo_1 2 W_{1 . 95} Bi_1 . 51 Fe_1 . Five Co_{7 . 90}Ni_{0 . 05}Cs_0 .50Si_{1 . 0}
(Oxidation reaction)
  In Example 1, the oxidation reaction was performed under the same reaction conditions as in Example 1 except that the catalyst (3) was used instead of the catalyst (1). The results are shown in Table 2.
(Catalyst strength measurement method)
  For the catalyst (3), the catalyst strength was measured under the same measurement conditions as in Example 1. The results are shown in Table 1.
Comparative Example 1
(Preparation of catalyst)
  In Example 2, a catalyst (4) was prepared in the same manner as in Example 2 except that the catalyst B was not added.
Comparative Example 2
(Preparation of catalyst)
  In Example 2, the catalyst (5) was prepared in the same manner as in Example 2 except that the slurry A was heated and stirred at 230 ° C., and most of the water was evaporated to obtain a cake-like dried product (dried product C). did.
Comparative Example 3
(Preparation of catalyst)
  A dried product C was obtained in the same manner as in Example 2.
  Separately, 750 g of ammonium paramolybdate and 191.2 g of ammonium paratungstate were added to 1 liter of heated ion-exchanged water, and dissolved while stirring. Separately, 824.3 g of cobalt nitrate, 214.6 g of ferric nitrate and 34.5 g of cesium nitrate were dissolved in 500 ml of ion-exchanged water. Also, 257.6 g of bismuth nitrate was dissolved in an aqueous nitric acid solution consisting of 150 ml of ion exchange water and 25 ml of concentrated nitric acid. These two aqueous solutions were dropped into the separately prepared aqueous solution and mixed, and then 106.4 g of silica sol having a concentration of 20% by mass was added and mixed. The slurry thus obtained was heated and stirred, evaporated to dryness, water was added as a molding aid, molded into pellets having an outer diameter of 6 mm and a length of 6.6 mm, dried, and 500 ° C. under air flow. Calcined for 6 hours at primary finished catalyst (catalystE) The resulting catalyst E is pulverized and then dried.CIn addition, after mixing well, water is added as a molding aid, molded into pellets having an outer diameter of 6 mm and a length of 6.6 mm, dried, and then calcined at 500 ° C. for 6 hours under air flow to form a catalyst (6 ) The elemental composition of the catalyst (6) was as follows in terms of atomic ratio.
Mo_1 2 W₂ Bi_1 . FiveFe_1 . FiveCo₈Cs_0 . FiveSi₁
(Oxidation reaction)
  In Example 1, the oxidation reaction was performed under the same reaction conditions as in Example 1 except that the catalyst (4), the catalyst (5), and the catalyst (6) were used instead of the catalyst (1). The results are shown in Table 1.
  By comparing Example 1, Example 2 and Example 3 with Comparative Example 1, Comparative Example 2 and Comparative Example 3, the catalyst (1), catalyst (2) and catalyst (3) of the present invention are comparative catalysts. It can be seen that (4), catalyst (5) and catalyst (6) are superior in catalytic activity.
(Catalyst strength measurement method)
  Regarding the catalyst (4), the catalyst (5), and the catalyst (6), the catalyst strength was measured under the same measurement conditions as in Example 1. The results are shown in Table 1. By comparing Example 1 and Example 2 with Comparative Example 1, Comparative Example 2 and Comparative Example 3, the catalyst (1), the catalyst (2) and the catalyst (3) of the present invention were compared with the comparative catalyst (4), It can be seen that the catalyst strength is superior to that of the catalyst (5) and the catalyst (6).
Example 4
  In Example 1, the oxidation reaction was performed for 4000 hours. The results after 4000 hours are shown in Table 1. As shown in Table 1, even after 4000 hours of oxidation reaction, the decrease in conversion is small and the yield is hardly decreased. This shows that a stable oxidation reaction can be continued for a long time by using the catalyst (1).
Example 5
  In Example 2, the oxidation reaction was performed for 4000 hours. The results after 4000 hours are shown in Table 1. As shown in Table 1, even after 4000 hours of oxidation reaction, the decrease in conversion is small and the yield is hardly decreased. This shows that a stable oxidation reaction can be continued for a long time by using the catalyst (2).
Example 6
  In Example 3, the oxidation reaction was performed for 4000 hours. The results after 4000 hours are shown in Table 1. As shown in Table 1, even after 4000 hours of oxidation reaction, the decrease in conversion is small and the yield is hardly decreased. This shows that a stable oxidation reaction can be continued for a long time by using the catalyst (3).
Comparative Example 4
  In Comparative Example 1, the oxidation reaction was performed for 4000 hours. The results after 4000 hours are shown in Table 1.
Comparative Example 5
  Comparative example3The oxidation reaction was carried out for 4000 hours. The results after 4000 hours are shown in Table 1.
  From the comparison of Example 4, Example 5 and Example 6 with Comparative Example 3 and Comparative Example 4, the comparative catalyst (4) and catalyst (6) had a problem in catalyst life, When used in the reaction, it can be seen that the conversion and yield are greatly reduced.
[Table 1]
Example 7
  In Example 2, the reaction temperature was 360 ° C. and the space velocity was 2500 hr.^- 1 Example except for changing to (STP)2The oxidation reaction was carried out in the same manner as above. The results are shown in Table 2.
Comparative Example 6
  Example 7 except that the catalyst (4) was used instead of the catalyst (2) in Example 7.7The oxidation reaction was carried out in the same manner as above. The results are shown in Table 2.
  From the comparison between Example 7 and Comparative Example 6, it can be seen that the catalyst (2) of the present invention is superior in activity and yield to the comparative catalyst (4) even under high space velocity conditions.
Example 8
  In Example 2, the oxidation reaction was performed in the same manner as in Example 2 except that the contents of isobutylene and nitrogen in the raw material gas were changed to 7.5% by volume and 71.5% by volume, respectively. The results are shown in Table 2.
Comparative Example 7
  In Example 8, the oxidation reaction was performed under the same reaction conditions as in Example 8 except that the catalyst (4) was used instead of the catalyst (2). The results are shown in Table 2.
  From comparison between Example 8 and Comparative Example 7, it can be seen that the catalyst (2) of the present invention is superior in activity and yield compared to the comparative catalyst (4) even under high isobutylene gas concentration conditions.
[Table 2]
Example 9
  In Example 2, a mixed gas composed of 5% by volume of methyl-t-butyl ether (MTBE), 13% by volume of oxygen, 8% by volume of water vapor and 74% by volume of nitrogen is used as a raw material gas used in the oxidation reaction, and the reaction temperature is set. Changed to 360 ° C, and space velocity was 1100 hr^- 1The oxidation reaction was carried out under the same reaction conditions as in Example 2 except that the change was made to (STP). The results are shown in Table 3.
Comparative Example 8
  In Example 9, the oxidation reaction was performed under the same reaction conditions as in Example 9 except that the catalyst (4) was used instead of the catalyst (2). The results are shown in Table 3.
[Table 3]
Example 10
(Catalyst preparation)
  To 2 liters of heated ion exchange water, 1500 g of ammonium paramolybdate and 286.8 g of ammonium paratungstate were added and dissolved with stirring. Separately, 1030.3 g of cobalt nitrate, 343.3 g of ferric nitrate, and 4.3 g of potassium nitrate were dissolved in 1 liter of ion-exchanged water. Further, 412.1 g of bismuth nitrate was dissolved in an aqueous nitric acid solution consisting of 300 ml of ion-exchanged water and 50 ml of concentrated nitric acid. These two aqueous solutions were picked and mixed into the separately prepared aqueous solution, and then 276.5 g of a silica sol having a concentration of 20% by mass was added and mixed to obtain a slurry. The slurry thus obtained was heated and stirred at 150 ° C., and most of the water was evaporated to obtain a cake-like dried product (dried product G).
  Separately, 75 g of ammonium paramolybdate and 14.3 g of ammonium paratungstate were added to 100 ml of ion-exchanged water heated and dissolved while stirring. Separately, 51.5 g of cobalt nitrate, 17.2 g of ferric nitrate and 0.21 g of potassium nitrate were dissolved in 50 ml of ion-exchanged water. Further, 20.6 g of bismuth nitrate was dissolved in an aqueous nitric acid solution consisting of 15 ml of ion-exchanged water and 2.5 ml of concentrated nitric acid. These two aqueous solutions were dropped into the separately prepared aqueous solution and mixed, and then 13.8 g of a silica sol having a concentration of 20% by mass was added and mixed. The slurry thus obtained was heated and stirred, evaporated to dryness, water was added as a molding aid, molded into pellets having an outer diameter of 6 mm and a length of 6.6 mm, dried, and 500 ° C. under air flow. Was calcined for 6 hours to obtain a primary completed catalyst (Catalyst H).
  Obtained catalystHAfter crushing, dry matterGIn addition, after mixing well, water is added as a molding aid, formed into pellets having an outer diameter of 6 mm and a length of 6.6 mm, dried, and then calcined at 450 ° C. for 6 hours under air flow to form a catalyst (7 ) The elemental composition of the catalyst (7) was as follows in terms of atomic ratio.
Mo_1 2 W_1 . FiveBi_1 . 2Fe_1 . 2Co_FiveK_0 . 0 6Si_1 .3
(Oxidation reaction)
  1200 ml of catalyst (7) was charged into a steel reactor having a diameter of 25 mm. A mixed gas having a composition of 6% by volume of propylene, 12% by volume of oxygen, 10% by volume of water vapor and 72% by volume of nitrogen was introduced into the reactor, and the reaction temperature was 310 ° C. and the space velocity was 2000 hours.^- 1The oxidation reaction was performed with (STP). The results are shown in Table 4.
(Catalyst strength measurement method)
  For the catalyst (7), the catalyst strength was measured under the same measurement conditions as in Example 1. The results are shown in Table 4.
Comparative Example 9
(Preparation of catalyst)
  In Example 10, the catalystHA catalyst (8) was prepared in the same manner as in Example 10 except that was not added.
(Oxidation reaction)
  In Example 10, the oxidation reaction was performed under the same reaction conditions as in Example 10 except that the catalyst (8) was used instead of the catalyst (7). The results are shown in Table 4.
  Comparison between Example 10 and Comparative Example 9 shows that the catalyst (7) of the present invention is superior in catalytic activity to the comparative catalyst (8).
(Catalyst strength measurement method)
  For the catalyst (8), the catalyst strength was measured under the same measurement conditions as in Example 1. The results are shown in Table 4. A comparison between Example 10 and Comparative Example 9 shows that the catalyst (7) of the present invention is superior in catalyst strength to the comparative catalyst (8).
Example 11
  In Example 10, the oxidation reaction was performed for 4000 hours. The results after 4000 hours are shown in Table 4.
  As shown in Table 4, after 4000 hours of the oxidation reaction, the decrease in the conversion rate is small and the yield is hardly decreased. This shows that a stable oxidation reaction can be continued for a long time by using the catalyst (7).
Comparative Example 10
  In Comparative Example 9, the oxidation reaction was performed for 4000 hours. The results after 4000 hours are shown in Table 4.
  From a comparison between Example 11 and Comparative Example 10, a comparative catalyst (8) Has a problem in the catalyst life, and when this is used for a long-time reaction, it is understood that the conversion rate and the yield are greatly reduced.
[Table 4]

Claims (3)

At least one compound selected from propylene, isobutylene, t-butanol and methyl-t-butyl ether is vapor-phase oxidized using molecular oxygen or a molecular oxygen-containing gas to produce the corresponding unsaturated aldehyde and unsaturated carboxylic acid. General formula (1):
MoaWbBicFedAeBfCgDhEiOx (1)
(Where Mo is molybdenum, W is tungsten, Bi is bismuth, Fe is iron, A is at least one element selected from nickel and cobalt, B is at least one element selected from alkali metals and thallium, and C is an alkali. At least one element selected from earth metals, D is at least one element selected from phosphorus, tellurium, antimony, tin, lead, niobium, manganese, arsenic and zinc, E is at least one selected from silicon, aluminum and titanium And O represents oxygen, and a, b, c, d, e, f, g, h, i, and x represent Mo, W, Bi, Fe, A, B, C, D, E, and Represents an atomic ratio of O, and when a is 12, b is 0 to 10, c is 0.1 to 10, d is 0.1 to 20, e is 2 to 20, and f is 0.001. 10, g is 0, h is 0 to 4, i is 0 to 30, x is a numerical value determined by the oxidation state of each element)
In a catalyst represented, after mixing a part of the raw material compounds containing all of the elemental constituents elements of the finished catalyst, dried, fired to produce a primary complete catalyst, and then with said primary finished catalyst 200 ℃ after mixing the remaining material compounds do not undergo the above thermal history, dried state, and are not obtained by sintering, in a proportion of 1% to 30% relative to the total weight of the primary finished catalyst final catalyst A catalyst for the production of unsaturated aldehydes and unsaturated carboxylic acids. The unsaturated aldehyde and unsaturated carboxylic acid production catalyst according to claim 1, wherein the primary finished catalyst is produced by calcination at 300 to 600 ° C (excluding 600 ° C). At least one compound selected from propylene, isobutylene, t-butanol and methyl-t-butyl ether is vapor-phase oxidized using molecular oxygen or a molecular oxygen-containing gas to produce the corresponding unsaturated aldehyde and unsaturated carboxylic acid. In doing so, a method for producing an unsaturated aldehyde and an unsaturated carboxylic acid, wherein the catalyst according to claim 1 or 2 is used as a catalyst.