TWI247628B - Production Process for unsaturated aldehyde - Google Patents

Abstract

The present invention provides a process in which, when an unsaturated aldehyde and/or an unsaturated carboxylic acid are produced by carrying out a catalytic gas phase oxidation reaction by using a fixed-bed multitubular reactor which is packed with a molybdenum-containing catalyst, the deterioration of the catalyst as located at a hot spot portion can be suppressed; so that the reaction can be continued for a long time while a high yield is maintained, regardless of where the hot spot portion occurs and also even if the concentration of a raw gas is high. An oxide and/or a complex oxide including molybdenum, bismuth, and iron as essential components are used as the catalysts, and the inside of each reaction tube of the fixed-bed multitubular reactor is divided in a tubular axial direction to thus arrange at least two reaction zones, and then these reaction zones are packed with the catalysts in such a manner that the ratio R of the apparent density of the catalyst to the true density of the catalyst (apparent density of catalyst/true density of catalyst) in each reaction zone differs from that in another reaction zone.

Description

1247628 (1) Description of the Invention [Technical Field of the Invention] The present invention relates to a process for producing an unsaturated aldehyde and/or an unsaturated carboxylic acid. In particular, it relates to a fixed-bed multitubular reactor using a ruthenium catalyst, and at least one compound selected from the group consisting of propylene, isobutylene, tert-butanol and methyl tert-butyl ether as a raw material' and via a molecule A method of producing an unsaturated aldehyde and/or an unsaturated carboxylic acid by gas phase contact oxidation with oxygen or a gas containing molecular oxygen. [Prior Art] A fixed-bed multitubular reactor using a ruthenium catalyst, and using at least one compound selected from the group consisting of propylene, isobutylene, tert-butanol, and methyl-tert-butyl ether as a raw material' and via a molecule A method in which gaseous oxygen or a gas containing molecular oxygen is subjected to vapor phase contact oxidation to produce an unsaturated aldehyde and/or an unsaturated carboxylic acid, respectively, has been reported so far (for example, Japanese Patent Publication No. Sho 53-30688) Japanese Laid-Open Patent Publication No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. There are also methods that have been industrially implemented, such as the special opening ι〇-168〇〇3 bulletin, etc.). Since this vapor phase contact oxidation reaction is accompanied by a very high heat generation reaction, a local abnormal high temperature portion (hereinafter referred to as a hot spot portion) is generated in the catalyst layer. In particular, the implementation of the oxidation reaction using a fixed-bed multi-tubular reactor does not prevent the occurrence of hot spots in the catalyst layer. If the temperature of the hot spot is high, it will cause excessive oxidation reaction and the yield will drop -5- (2) 1247628, and in the worst case, it will cause the runaway reaction. Further, since the catalyst located in the hot spot is exposed to a high temperature, the physical properties and chemical properties of the catalyst change, and the catalyst which deteriorates the activity and the selection of the target product is deteriorated to be accelerated. , in particular, in the case of molybdenum-based catalysts, because the molybdenum component is sublimated and the catalyst composition

The V property is easy to change, so the degree of deterioration of the catalyst is large. ~ The above problems are more remarkable in the case of improving the productivity of the target product, performing the reaction at a high space velocity, and reacting at a high raw material gas concentration. _ With regard to the above problem, if attention is paid to the entire catalyst layer to be filled in the reaction tube, the catalyst at the hot spot is deteriorated faster than the catalyst of other portions, and the yield of the target product is remarkably lowered after long-term use. And it is difficult to make a stable manufacture. As described above, in the case of a molybdenum-based catalyst and a reaction at a high space velocity and a reaction at a high raw material gas concentration, the degree of deterioration of the catalyst is particularly large. SUMMARY OF THE INVENTION [Problems to be Solved by the Invention] Any of the above-mentioned conventionally known proposals are directed to the proposal of lowering the temperature of the hot spot. However, when the oxidation reaction using a fixed-bed multi-tubular reactor is carried out, the hot spot cannot be completely formed in the catalyst layer, and the deterioration of the catalyst at the hot spot cannot be solved to be worse than the deterioration of the catalyst located in other portions. Relatively big problem. In particular, this problem is remarkable in the case of using a molybdenum-based catalyst and a reaction at a high-altitude gas concentration. Therefore, the object of the present invention is to provide an unsaturated Sf-based and/or unsaturated carboxylic acid by a vapor phase contact oxidation reaction using a ruthenium-doped -6-(3) 1247628 fixed bed multitubular reactor. In the case of suppressing the deterioration of the catalyst at the hot spot portion, and depending on where the hot spot portion occurs and the concentration of the raw material oxygen is high, the reaction can be continued for a long period of time while maintaining a high yield. [Means for Solving the Problems] The present inventors conducted an effort to review the above problems. The result 'focuses on the apparent density ratio R of the catalyst relative to the true density of the catalyst (the apparent density of the catalyst / the true density of the catalyst), and finds that the relatively high catalytic ratio of R is lower than that of the lower catalyst. Exposure at high temperatures also causes a small degree of deterioration. Therefore, it is conceivable that the preparation of R is a different catalyst, and the above-mentioned problem can be solved by charging the catalyst of R high in the vicinity of the hot spot and the vicinity thereof. That is, the method for producing the unsaturated aldehyde and/or unsaturated carboxylic acid of the present invention is a fixed-bed multitubular reactor using a ruthenium-charged catalyst, and is propylene, isobutylene, tert-butanol, and methyl- The at least one compound selected from the third butyl ether is used as a raw material, and is subjected to vapor phase contact oxidation by molecular oxygen or a gas containing molecular oxygen to produce an unsaturated aldehyde and/or an unsaturated carboxylic acid corresponding to the raw material. The catalyst is an oxide and/or a composite oxide using molybdenum, niobium, and iron as essential components, and the reaction tubes inside the fixed-bed multi-tubular reactor are divided into a plurality of reactions in the tube axis direction. band. Further, in each of the reaction bands, the above-mentioned catalysts having different apparent density ratios R (the apparent density of the catalyst/the true density of the catalyst) which are different from the true density of the catalyst are characterized. (4) 1247628 [Embodiment of the Invention] The catalyst used as the essential component of molybdenum, niobium and iron in the present invention is selected from the group consisting of propylene, isobutylene, tert-butanol and methyl-tert-butyl ether. At least one compound is used as a raw material, and a corresponding unsaturated aldehyde and/or unsaturated carboxylic acid can be produced by a vapor phase contact oxidation reaction, and the composite oxide shown by the following general formula (1) can be used. The media is suitable for use.

MoaWbBicFedAeBfCgDhEiOx (1) (here, Mo is molybdenum, W is tungsten, Bi is bismuth, Fe is iron, A is at least one element selected from cobalt and nickel, and B is composed of sodium, potassium, strontium, planer and strontium. At least one element selected, C is at least one element selected from the group consisting of boron, phosphorus, chromium, manganese, zinc, arsenic, antimony, tin, antimony, bismuth, antimony and lead, and D is composed of antimony, aluminum, titanium and chromium. At least one element selected, E is at least one element selected from alkaline earth metals, 0 is oxygen, and a, b, c, d, e, f, g, h, i and x represent Mo, W, Bi, Fe, respectively. , atomic ratio of A, B, C, D, E and 0, a: 12, 0SbS5, 0.1Sb$5, O.lScglO, 0.1$d$20, 1 ^ 20 ' 0.001 ^ 5 > g $10, 0$ hS30, 0$i^5, and x are the number determined according to the oxidation state of each element). The starting material of the above-mentioned catalyst component element is not particularly limited, and is generally an ammonium salt, a nitrate, a carbonate, a chloride, a sulfate, a hydroxide, or an organic acid salt of a metal element used for such a catalyst. Oxide or a mixture of these may be used in combination, but ammonium salt and nitrate are preferred. (5) 1247628 Catalyst raw material salt mixed aqueous solution or aqueous slurry can be generally used according to the catalyst. The method is prepared by, for example, using the above-mentioned catalyst raw material as an aqueous solution, and mixing them in order. There is no particular limitation on the mixing strip of the catalyst material (mixing order, temperature, pressure, pH, etc.). The mixed aqueous solution or aqueous slurry of the catalyst raw material salt thus obtained may be concentrated and dried as needed to obtain a cake-like solid. The aqueous mixture of the catalyst raw material salt, the aqueous slurry or the cake-like solid is heat-treated to obtain the catalyst precursor P1. The heat treatment method for obtaining the catalyst precursor P1 and the form of the catalyst precursor are not particularly limited. For example, a powdery catalyst precursor can be obtained by using a spray dryer or a drum dryer, and a box can also be used. A dryer or a tunnel dryer is heated in a gas stream to obtain a bulk or sheet-like catalyst precursor. The catalyst precursor P 1 preferably has a reduction ratio of 1% by mass or more and less than 40% by mass, more preferably 13% by mass to 37% by mass, and still more preferably 15% by mass to 35% by mass. Set the heat treatment conditions. However, even if the reduction rate is outside the above range, it can be used. ® Reduction rate of catalyst precursor The catalyst precursor P1 was uniformly mixed and weighed about 10 g, and it was heated at 300 °C for 1 hour under air atmosphere and ~ was calculated as follows. ' Reduction rate (% by mass) = (catalyst precursor mass - catalyst precursor mass after heating) / catalyst precursor mass χίοο ^ The reduction portion is the catalyst precursor for decomposing 'volatile' sublimation via heating Nitrate, ammonium, etc. remaining in P 1 and water. (Identifies that the nitrate and ammonium salts contained in the precursor P1 are decomposed by heating at a high temperature and are removed by the -9 - (6) 1247628 catalyst precursor P 1. That is, the higher the reduction rate is contained The higher the ratio of nitrate, ammonium salt, etc.). The above-described heat treatment conditions are appropriately selected depending on the type of the heating device (dryer) and the characteristics of the heating device, and cannot be specified. For example, when a box type dryer is used, the catalyst precursor is, for example, gas-flowed, 23 It can also be obtained by heating at a temperature of 0 ° C or lower for 3 to 24 hours. The catalyst precursor P 1 adjusted to the preferred reduction ratio as described above is a pulverization step and a classification step which are obtained by obtaining an appropriate particle size as needed, and then sent to a molding step. For the catalyst precursor P1 whose reduction ratio is adjusted to the above preferred range, a binder is added and mixed to form a catalyst precursor P2. The type of the binder to be added and mixed with the catalyst precursor P1 is not particularly limited. For example, a known binder which can be used in the catalyst molding is used, and water is preferred. The amount of the binder added and mixed to the catalyst precursor P1 is preferably such that the amount of water added to and mixed with the catalyst precursor Pi is preferably 5 parts by mass or more based on 1 part by mass of the catalyst precursor P1. 3 parts by mass or less, more preferably 8 parts by mass or more and 27 parts by mass or less, and more preferably 24 parts by mass or less. When the amount is more than 30 parts by mass, the mold precursor p2 is deteriorated in moldability and may not be molded. If the amount of addition is less than 5 parts by mass, the bonding of the catalyst precursors P2 to each other is weak, and the molding itself cannot be molded or the molding can be molded, and the mechanical strength of the catalyst is lowered. In the worst case of extrusion, the molding machine is damaged. -10- (7) 1247628 The water added to the catalyst precursor P1 may be added as an aqueous solution of various substances and a mixture of various substances and water. The material to be added together with the water may be a molding aid which improves moldability, a reinforcing agent and a binder which improve the strength of the catalyst, and a material which is generally used for forming a pore-forming pore forming agent. These materials are preferably those which do not adversely affect the catalytic properties (activity, selectivity of the desired product) by addition. That is, (i) an aqueous solution of a solution which does not remain in the catalyst after calcination or a mixture with water, and (ii) a substance which does not adversely affect the catalytic performance even if it remains in the catalyst after calcination, Or a mixture with water. Specific examples of the above (i) include organic compounds such as ethylene glycol, glycerin, propionic acid, maleic acid, benzyl alcohol, propanol, butanol or phenol, and nitric acid, nitric acid, and carbonation mirrors. Wait. Specific examples of the above (Π) include vermiculite, alumina, glass fiber, niobium carbide, tantalum nitride, and the like which are generally known as reinforcing agents. If the catalyst produced in accordance with the present invention has practically sufficient mechanical strength, such reinforcing agents may be added if higher mechanical strength is required. When the amount of such a substance is excessive, the mechanical strength of the catalyst is remarkably lowered. Therefore, it is preferable to add the amount of the mechanical strength of the catalyst to the extent that it is impossible to use it as an industrial catalyst. When an aqueous solution of the above various substances and a mixture of various substances and water are added, for example, when 100 parts by mass of the catalyst precursor P1 is added in an amount of 20 parts by mass of a 5 mass% aqueous solution of ethylene glycol and molded, in P 1 The amount of water added is 2〇x (1- 0.05) = 19 parts by mass. -11 - (8) 1247628 The catalyst used in the present invention may be a molding catalyst for molding the catalyst precursor P2 into a certain shape, or carrying the catalyst precursor P2 on any inert carrier having a shape. The carrier catalyst or a combination of such molding catalyst-carrying catalysts is preferably a molding catalyst for molding the catalyst precursor P2 into a constant shape. The shape of the above-mentioned catalyst is not particularly limited, and may be any shape such as a spherical shape, a circular shape (nine shape), a ring shape, or an amorphous shape. Of course, the spherical condition does not have to be a spherical shape but a substantially spherical shape. The same is true for the circle and the ring. Further, the shape of the catalyst charged in each reaction zone may be the same or different (for example, the gas inlet side: the spherical catalyst gas outlet side: the nine-shaped catalyst), but usually the same shape is formed. A carrier or a carrier of the same shape is preferred. The size of the above-mentioned catalyst is spherical in shape, and the particle diameter of the flat catalyst is preferably 1 to 15 mm, more preferably 1 to 10 mm, still more preferably 10 mm, and even more preferably 3 to 8 mm. Suitable for use. The pore volume of the catalyst is preferably 0.2 to 0.6 cm 3 /g, more preferably 0. to 0.55 m 3 /g. In the case of carrying a catalyst, the carrier material itself is not particularly limited to gas phase oxidation of acrolein. A carrier which is often used in the production of a catalyst for producing acrylic acid can be used. Specific examples of the carrier which can be used include aluminum oxide, vermiculite, vermiculite-alumina, titanium oxide, magnesium oxide, vermiculite-magnesium, vermiculite-magnesia-alumina, niobium carbide, niobium nitride, and zeolite crucible. In the case of the catalyst, the carrying capacity of the catalyst in each reaction zone is similar to that of the column, and the column can be Prmt, the average of 25, the oxygen, etc. is -12 - 1247628 Ο) Considering the oxidation reaction conditions, catalyst activity, and strength Etc., the appropriate determination of the optimum activity and selectivity, but preferably 5 to 9 5 %, more preferably 2 0 to 90%, particularly preferably 3 0 to 8 5 %. Further, in the present invention, the carrier loading ratio is calculated according to the following formula. Bearing ratio (%) ' = [(the weight of the catalyst after calcination - the weight of the carrier) / the weight of the catalyst after calcination] X 100 The heat treatment conditions (so-called calcination conditions) when the catalyst is modulated are also not particularly limited, and The calcination conditions generally employed can be applied to the manufacture of such catalysts. The heat treatment temperature of the catalyst charged in each reaction zone may be the same or different, and the heat treatment temperature is preferably 3 50 to 600 ° C, more preferably 400 to 5 50 ° C, and the heat treatment time is preferably 1 to 1 1 hour. The molding method of the catalyst may be a conventionally known method, and a molding method such as extrusion molding, tablet molding, granulation (rotary granulation, centrifugal flow coating), and rounding may be applied. Among them, extrusion molding is suitable. Φ In the method for producing an unsaturated acid and/or an unsaturated residual acid of the present invention, a plurality of reaction zones are disposed in the inside of each reaction tube of the fixed-bed multi-tubular reactor in the direction of the tube axis, and In the respective reaction bands, the above-mentioned catalysts having different apparent density ratios R (the apparent density of the catalyst/the true density of the catalyst) of the catalysts with respect to the true density of the catalyst are characterized. Further, in the present invention, the apparent density of the catalyst is 1 / (1/ true density + pore volume). · The so-called carrier-type catalyst for carrying the carrier active material -13- (10) 1247628

In the form, the catalyst active material is peeled off only by the surface of the carrier by any method, and only the true density and the pore volume of the catalyst active material are measured, and R 〇 is calculated from the above formula, and the catalyst is superimposed on the true density. In the case of producing a unsaturated aldehyde and/or an unsaturated carboxylic acid by a gas phase contact oxidation reaction using a fixed-bed multi-tubular reactor using a molybdenum-based catalyst, the density ratio R is different, and does not depend on the case. Where the hot spot occurs, and in the case where the concentration of the raw material gas is high, the reaction can be continued for a long period of time while maintaining a high yield. The method for producing a catalyst having a different apparent density ratio R than the true density is not particularly limited. For example, it can be produced by the following methods (1) to (4) or a combination thereof. (1) Changing the reduction rate of the catalyst precursor can change R. If the reduction rate is low, the pore formation of the catalyst is reduced, so that the apparent density of the catalyst becomes high. If the composition of the catalyst is not changed extremely, the degree of vacuum will not change even if the manufacturing method is changed. Therefore, if the reduction rate is low, R becomes large. On the other hand, if the reduction rate is high, the performance density of the catalyst becomes low, so R becomes small. (2) Control the type and/or amount of the pore forming agent added to the catalyst. When a pore-forming agent having a pore-forming effect is added to the catalyst, and the amount of addition thereof is relatively decreased, the expression density is increased and R is increased. Conversely, if the amount of addition is relatively large, R becomes small. Further, R can be controlled by changing the kind of the pore forming agent. (3) Although the effect of changing R is small, if the composition of the catalyst is changed (using the metal type and addition ratio as the raw material of the catalyst), the true density changes, so -14- (11) 1247628 R also changes. (4) R can also be controlled by changing the pressure at the time of molding. For example, in the case of ingot forming, if the pressure is increased, R becomes large, and if the pressing is lowered, R becomes small. Further, in the case of extrusion molding, if the extrusion pressure is increased, R becomes large, and if the extrusion pressure is lowered, R becomes small. The apparent density ratio R (the apparent density of the catalyst/the true density of the catalyst) of the true density of the catalyst used in the present invention is not particularly limited, but is preferably 0.25 to 0.55, more preferably 0.30 to 0.50. . When the apparent density ratio of the true density of the catalyst is less than 0.25, the diffusion efficiency in the pores increases as the pore volume increases. At this time, although the catalyst activity and the selectivity to the target product are increased, The strength of the media is significantly reduced, so it is not good. When the apparent density ratio with respect to the true density of the catalyst is more than 0.5, the catalyst strength is increased, but the catalyst activity and the selectivity to the target product are remarkably lowered, which is not preferable. In the present invention, a plurality of reaction zones are respectively disposed inside the reaction tubes of the fixed bed multitubular reactor in the tube axis direction, and the R prepared according to the above method is different in the plurality of reaction bands. The method of the above-described entanglement arrangement is not particularly limited, and for example, an arrangement in which R is made smaller by the gas from the gas inlet side toward the gas outlet side, and R from the gas inlet side toward the gas outlet side is used. It is preferable to arrange the catalysts having different R from the gas inlet side of each reaction tube toward the gas outlet side to be smaller as R in order to reduce the size of the reactor. That is, -15-(12) 1247628 arranges the R largest catalyst on the gas inlet side, and the catalyst with the smallest R is disposed on the gas outlet side. Further, in the charging arrangement in which the R is temporarily increased from the gas inlet side toward the gas outlet side, the length of the charging layer in which the R in the gas inlet portion is large is 60% or less of the total catalyst layer. Good, and 5~50% is better, and 10~4 0% is better. By using a plurality of catalysts having an apparent density ratio R (the apparent density of the catalyst/the true density of the catalyst) with respect to the true density of the catalyst, and using a fixed-bed multi-tube using a molybdenum-based catalyst In the gas phase contact oxidation reaction of the reactor, when the unsaturated aldehydes and/or unsaturated carboxylic acids are produced, the deterioration of the catalyst at the hot spot is suppressed, and the hot spot is not generated according to the hot spot, and the concentration of the raw material gas is In the case of high, it is possible to continue the reaction for a long period of time while maintaining high yield. Further, in the case where the catalyst activity is controlled using only a catalyst having different activities, in particular, when the concentration of the material gas is high, there is a limit. However, when the method of the present invention is used, even in the case where the concentration of the material gas is high, It is also possible not to start according to the hot spot, and to continue the reaction for a long time while maintaining the yield. In the method for producing an unsaturated aldehyde and/or unsaturated carboxylic acid of the present invention, it is preferred that the catalytic activity of each of the plurality of reaction zones is different. The method for producing the above-described different catalytic activity is not particularly limited, and for example, a conventionally known method can be used. Specifically, for example, a method of changing the type and/or the amount of at least one element selected from the group consisting of sodium, potassium, rubidium, planer and bismuth (the B component of the catalyst used in the present invention), changing the load factor, and changing the forging The method of burning the temperature, the method of changing the dilution rate, the method of combining the bearing (13) 1247628 medium and the molding catalyst, the method of changing the particle diameter of the catalyst, and the method of combining the same. When the catalysts having different activities are respectively charged to the plurality of reaction bands, that is, the apparent density ratio R of the catalyst (the apparent density of the catalyst/the true density of the catalyst) is different with respect to the true density of the catalyst. Further, when the catalysts having different activities are respectively charged to the plurality of reaction bands, the method of disposing the catalyst is not particularly limited, and the case of focusing on R is as described above, and for example, the gas inlet side is exemplified. In the case where R is a smaller charge toward the gas outlet side, and an arrangement in which R is temporarily increased from the gas inlet side toward the gas outlet side, the arrangement is reduced, but in the case of focusing on activity, For example, an arrangement in which the activity is increased from the gas inlet side toward the gas outlet side, and an arrangement in which the activity is temporarily lowered from the gas inlet side toward the gas outlet side, and the like is preferably increased. The catalysts having different activities are arranged such that the activity is increased in order from the gas inlet side of each reaction tube toward the gas outlet side. In other words, the catalyst having the lowest activity is disposed on the gas inlet side, and the catalyst having the highest activity is disposed on the gas outlet side. Further, in the arrangement in which the activity is temporarily lowered and then increased from the gas inlet side toward the gas outlet side, the length of the high-activity catalyst in the gas inlet portion is 60% or less of the total catalyst layer. It is preferably 5~50%, and 1 〇~4 0% is better. By arranging a plurality of catalysts having different activities, and by using a gas phase contact oxidation reaction using a fixed-bed multitubular reactor containing a molybdenum-based catalyst to produce unsaturated aldehydes and/or unsaturated carboxylic acids, It suppresses the deterioration of the catalyst at the hot spot and does not depend on where the hot spot occurs. Moreover, the concentration of the raw material gas is a situation, and the reaction can be continued for a long period of time while maintaining a high yield -17-(14) 1247628. The optimum form of the catalyst charging arrangement is such that R is smaller as R from the gas inlet side toward the gas outlet side, and the activity is from the gas inlet side toward the gas outlet side in order of activity. The form of the configuration is increased. The number of reaction zones is not particularly limited, and the more the temperature, the easier it is to control the hot spot temperature of the catalyst layer, but it is industrially possible to obtain a sufficient effect at about two or three. Further, the division ratio of the catalyst layer is optimal depending on the oxidation reaction conditions and the composition, shape, and size of the catalyst to be added to each layer, and it is not possible to specify the optimum activity and selectivity as appropriate. Just fine. When the catalyst is charged for each reaction tube, the catalyst diluted with the inert substance may be charged to each reaction zone. At least one compound selected from the group consisting of propylene, isobutylene, tert-butanol, and methyl-tert-butyl ether is used as a raw material, and gas phase contact oxidation is performed via molecular oxygen or a gas containing molecular oxygen to produce a corresponding raw material. The method of the unsaturated aldehyde and/or the unsaturated carboxylic acid is not particularly limited, except that the catalyst of the present invention is used as a catalyst, and can be carried out under generally used apparatuses, methods and conditions. Namely, the gas phase contact reaction in the present invention can be carried out in accordance with a usual single-flow method or a circulation method, and a fixed bed reactor, a fluidized bed reactor, a moving bed reactor or the like can be used as the reactor. The reaction conditions described above are, for example, at least one selected from the group consisting of propylene, isobutylene, tert-butanol and methyl-tert-butyl ether as a raw material gas, -18-(15) 1247628 1 to 15% by volume, relative to this Molecular oxygen having a material gas volume ratio of 1 to 10 times and an inert gas as a diluent, for example, a mixed gas of water vapor, nitrogen, and carbonic acid gas at a temperature range of 250 to 450 ° C, 0.1 It can be contacted with the catalyst of the present invention at a space velocity of 300 ft to 5000 hr. 1 (STP) at a pressure of -1 MPa. According to the method of the present invention, under the conditions of high load reaction for the purpose of improving productivity, for example, at a higher raw material gas concentration or a higher space velocity, a particularly remarkable result can be obtained than the prior art. In particular, even if the concentration of the raw material gas used is 7 vol% or more, it is more strictly 9 vol. /. The above-mentioned high concentration of the raw material gas can also achieve the object of the present invention. [Embodiment] [Examples] Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the examples. Further, the conversion ratio, the selection ratio, and the yield in the present specification are respectively defined as follows. Conversion rate (% by mole) = (mole of starting material of the reaction) / (mole of starting material supplied) X 100 selectivity (mol%) = (unsaturated aldehydes formed and/or not The number of moles of saturated carboxylic acid) / (the number of moles of starting material supplied) X 100 Further, the true density and pore volume of the catalyst were measured by the following measuring apparatus and method. True density: -19- 1247628 (16) Measuring machine: Autopycnometer manufactured by Micromeritics Inc. 1320 Measurement method: About 4 g of catalyst was weighed and placed in a measuring element and mounted on the above measuring machine. Pore volume: Measuring machine: AutoPore III manufactured by Micromeritics Co., Ltd. (Mercury press-in method) Measurement method: About 2 g of catalyst was weighed and measured under a pressure measurement range of 4 4 4 MPa, and an equivalent time of 10 seconds. (Catalyst Production Example 1: Preparation of Catalyst (1)) While heating and stirring 1 liter of pure water, 1 500 g of ammonium molybdate was dissolved, and 425 g of a 20% by mass vermiculite gel was further added. To the mixture, 1 23 6 g of cobalt nitrate, 412 g of nickel nitrate, 3 72 g of ferric nitrate, and 5.7 g of potassium nitrate dissolved in 1 000 ml of pure water were dripped while vigorously stirring. Thereafter, an aqueous solution of concentrated 250 ml of nitric acid was added to 500 ml of pure water, and a liquid of 446 g of dissolved cerium nitrate was added dropwise while vigorously stirring. The resulting suspension was heated and stirred to evaporate most of the water to obtain a cake-like solid. The obtained cake-like solid matter was heat-treated in a box dryer (heating gas temperature: 1 7 ° C, heating gas line speed: 1 · 2 m/sec, heat treatment time: 12 hours), and obtained a block shape. Catalyst precursor. After the catalyst precursor was crushed, the weight loss rate was measured and found to be 18.9% by mass. Next, an aqueous solution of 50% by mass of ammonium nitrate was added in a ratio of -20 to 1247628 (17) 260 g to 1 kg of the catalyst precursor powder and kneaded for 1 hour, and then extruded into an outer diameter of 6.0 mm and an inner diameter of 2.0. Mm, a ring with a height of 6.0 mm. Next, the molded body was calcined at 480 ° C for 5 hours under air flow to obtain a catalyst (1). The composition of the metal element other than oxygen of this catalyst is as follows. Catalyst (1): MouCcuNhBiuFe^SizKo.os Catalyst (1) The apparent density ratio R (the apparent density of the catalyst/the true density of the catalyst) relative to the true density is 0.35. The catalyst composition of the catalyst (1), the reduction ratio of the catalyst precursor P1, the amount of the binder added to the catalyst precursor P1 100 parts by mass, the size of the catalyst, and the apparent density relative to the true density. The ratio R (the density of the catalyst and the true density of the catalyst) is summarized in Table 1. (Catalyst Production Examples 2 to 3: Modulation of Catalysts (2) to (3)) In the modulation method of the catalyst (1) of the catalyst production example 1, the addition to the catalyst precursor P1 is added. The catalyst composition of the catalyst (2) to (3) the catalyst (2) to (3) was obtained by the treatment of the catalyst production example 1 except that the amount of the 0 mass% ammonium nitrate aqueous solution was changed, respectively, and the catalyst precursor P1 was obtained. The reduction ratio is based on the amount of binder added to the catalyst precursor P1, 100 parts by mass, the size of the catalyst, and the apparent density ratio relative to the true density (the apparent density of the catalyst/the true density of the catalyst). In Table 1. (Catalyst Production Example 4: Modulation of Catalyst (4)) In the modulation method of the catalyst (1) of the above-described catalyst production example 1, except for -21 - (18) 1247628, the size of the catalyst is changed to With a diameter of 7.0 mm, an inner diameter of 2.0 mm, and a height of 7.0 mm, the catalytic medium (4) ° catalyst composition (4) catalyst composition and the catalyst precursor P1 reduction ratio 'relative to touch' were obtained. The amount of the binder added to the precursor of the precursor P1, the amount of the binder, the magnitude of the catalyst, and the apparent density R (the apparent density of the catalyst/the true density of the catalyst) with respect to the true density are summarized in Table 1. (Catalyst Production Example 5: Modulation of Catalyst (5)) In the preparation method of the catalyst (1) of the catalyst production example 1, the same catalyst was used except that the amount of potassium nitrate added was changed to 7.2 g. Example 1 Process the acquisition of the catalyst (5). The composition of the metal element other than oxygen of this catalyst is as follows. Catalyst (5) : The composition of the catalyst of MonCcuNhBiuFeuShKn catalyst (5), the reduction rate of the catalyst precursor P1, the amount of binder added to the catalyst precursor P1 100 parts by mass, the size of the catalyst, and the relative The apparent density ratio R (the density of the catalyst/the true density of the catalyst) at true density is summarized in Table 1. (Catalyst Production Example 6: Modulation of Catalyst (6)) In the method of preparing the catalyst (1) of the catalyst production example 1, in addition to the heat treatment conditions of the cake-like solid matter, the temperature of the heating gas is changed to 22 〇 t, and add 50 mass to the catalyst precursor P1. In addition to the change in the amount of the ammonium nitrate aqueous solution, the catalytic composition of the catalyst (6) -22- (19) 1247628 catalyst (6) is obtained by the catalyst production example 1, and the reduction ratio of the catalyst precursor P1 is relative to The amount of the binder added to the catalyst precursor P1 of 100 parts by mass, the size of the catalyst, and the apparent density ratio R (the density of the catalyst/the true density of the catalyst) with respect to the true density are summarized in Table 1. (Catalyst Production Example 7: Modulation of Catalyst (7)) In the method of preparing the catalyst (1) of the catalyst production example 1, the addition amount of potassium nitrate was changed to 3.6 g, and was added to The catalyst (7) was treated in the same manner as in the catalyst production example 1 except that the amount of the 50% by mass aqueous ammonium nitrate solution of the catalyst precursor P1 and the size of the catalyst were changed. The composition of the metal element other than oxygen of the catalyst is as follows. Catalyst (7) : MouCcuNhBi^Fe Bu 3Si2K0.05 Catalyst (7) Catalyst composition, the reduction rate of the catalyst precursor P1, the amount of binder added to the catalyst precursor P1 100 parts by mass, the catalyst The size, and the apparent density ratio R (the density of the catalyst/the true density of the catalyst) with respect to the true density are summarized in Table 1. (Catalyst Production Example 8 ♦ Modulation of Catalyst (8)) In the method of preparing the catalyst (7) of the catalyst production example 7, except for adding 50% by mass of ammonium nitrate added to the catalyst precursor P1 The catalyst (8) was treated in the same manner as in the catalyst production example 7 except that the amount of the aqueous solution was changed. The catalyst composition of the catalyst (8), the reduction rate of the catalyst precursor P1 'the amount of the binder added relative to the catalyst precursor P1 100 parts by mass, the size of the catalyst, and the apparent density relative to the true density The ratio R (the performance density of the catalyst / 1247628 (20) true density of the catalyst) is summarized in Table 1. (Catalyst Production Example 9: Modulation of Catalyst (9)) In the preparation method of the catalyst (1) of the above-mentioned catalyst production example 1, 9.7 g of nitric acid was used instead of potassium nitrate, and the catalyst was added to the catalyst. 50 mass of the precursor P 1 . /. The catalyst (9) was treated in the same manner as in the catalyst production example 1 except that the amount of the ammonium nitrate aqueous solution and the size of the catalyst were changed. The composition of the metal element other than oxygen in this catalyst is as follows. · Catalyst (9) : MouCc^N^BiuFeuShKo.o? The catalyst composition of the catalyst (9), the reduction rate of the catalyst precursor P1 is relative to the amount of the binder added to the catalyst precursor P1 100 parts by mass. The size of the catalyst, and the apparent density ratio R (the density of the catalyst/the true density of the catalyst) with respect to the true density are summarized in Table 1. (Catalyst Production Example 10: Modulation of Catalyst (10)) In the modulation method of the catalyst (9) of the above-mentioned catalyst production example 9, 50% by mass of nitric acid added to the catalyst precursor 除 1 was removed in addition to β. The catalyst (10) was treated in the same manner as in the catalyst production example 9 except that the amount of the ammonium aqueous solution was changed. The catalyst composition of the catalyst (1〇), the reduction rate of the catalyst precursor Ρ1, the phase-the amount of the binder added to the catalyst precursor Ρ1 1 〇〇 mass, the size of the catalyst, and the true density The apparent density ratio R (the performance density of the catalyst / the true density of the catalyst) is summarized in Table 1. (Reference Example 1 to 1 〇) -24 - (21) 1247628 In the reaction tube of an inner diameter of 25 mm stainless steel heated by molten nitrate, the catalyst (1) to (1) obtained by the catalyst production example 1 to 1 is used. 10) The mixture was heated to a layer length of 2 〇〇 mm, and a reaction gas of the following composition was introduced at a space velocity of 1 5 001 Γ 1 (STP) to carry out a vapor phase contact oxidation reaction of propylene. The results are shown in Table 2. Propylene 3% by volume Air 30% by volume Water vapor 40% by volume Nitrogen 2 75% by volume (Example 1) In the reaction tube of an inner diameter of 25 mm stainless steel heated by molten nitrate, the reaction gas inlet side faces the outlet side In order, the catalyst (1) is charged at a layer length of 1 500 mm, the catalyst (2) is charged at a layer length of 1 500 mm, and the reaction gas of the following composition is introduced into the propylene gas at an air velocity of 1 500 h_ 1 (STP). Contact with oxidation reaction. The results are shown in Table 3. Propylene 5.6 vol% 5% air 5 0.0 vol% water vapor 1 0.0 vol% nitrogen 3 4.5 vol% (Comparative Examples 1 to 2) In Example 1, except that only the catalyst (1) was layered at a length of 3 000 mm, The medium (2) was subjected to an oxygen phase contact oxidation reaction in the same manner as in Example 1 except that the layer length was 3 〇〇〇mm. The results are shown in Table 3. (Example 2, Comparative Examples 3 to 4) In the first embodiment, a gas phase contact oxidation reaction was carried out in the same manner as in Example 1 except that the catalyst was charged as shown in Table 3, and the composition of the reaction gas was changed as follows. The results are shown in Table 3. Propylene 6.5 % by volume Air 5 7.0 % by volume • Water vapor 1 0.0% by volume Nitrogen 2 6.5 % by volume (Examples 3 to 5, Comparative Example 5) In Example 1, except that the catalyst was added as shown in Table 3, The gas phase contact oxidation reaction was carried out in the same manner as in Example 1 except that the composition of the reaction gas was changed as follows. The results are shown in Table 3. Propylene 8 . 〇 Capacity % • Air 7 0.0% by volume Water vapor 1 0.0% by volume Nitrogen 1 2.0% by volume • -26- (23) 1247628 (23)

Table 1 Catalyst catalyst composition Catalyst precursor binder Catalyst size R (catalyst table number P1 reduction rate addition amount outer diameter X inner diameter X density/catalyst (mass%) (mass parts) height (mm ) true density) (1) Mo12Co0Ni2BiuFe1.3Si2K0.08 18.9 26 6.0x 2.0x 6.0 0.35 (2) t 18.8 40 0.30 (3) t 19.0 20 t 0.43 (4) 19.0 26 7·0χ 2·0χ 7.0 0.35 (5) M〇nC〇 6Ni2BiuFeuSi2K〇.i 19.1 26 6·0χ 2.0χ 6.0 0.35 (6) MonCo6Ni2Bi1.3FeuSi2K0.08 2.1 42 0.56 (7) Mo12Co6Ni2Bi1.3FeuSi2K0.05 18.8 40 5.5χ 2.0χ 5.5 0.31 (8) 19.0 26 0.35 (9) MonCo6Ni2Bi1.3Fe1.3Si2K0. 07 19.1 20 7.0χ 2.0χ 7.0 0.42 (10) t 18.9 26 t 0.35

-27- (24) 1247628 (24)

Table 2 Reference Example Catalyst Number R (Performance Density of Catalyst / True Density of Catalyst) Reactance of CC) Propylene Conversion Rate (Mole %) Acryl Aldehyde + Acrylic Total Yield (Mole %) Acrolein + Acrylic Total Selection rate (% by mole) Reference example 1 (1) 0.35 310 98.2 92.4 94.1 Reference example 2 (2) 0.30 310 98.3 92.1 93.7 Reference example 3 (3) 0.43 310 96.8 91.8 94.8 Reference example 4 (4) 0.35 310 97.0 91.7 94.5 Reference Example 5 (5) 0.35 310 96.7 91.5 94.6 Reference Example 6 (6) 0.56 310 80.5 76.3 94.8 Reference Example 7 (7) 0.31 310 99.3 90.6 91.2 Reference Example 8 (8) 0.35 310 99.1 89.8 90.6 Reference Example 9 (9) 0.42 310 81.2 77.9 95.9 Reference Example 10 (10) 0.35 310 82.3 78.5 95.4

-28- (25) 1247628 Table 3 Catalyst charging method (gas inlet side - gas outlet side) Reaction time (hours) Reaction chick (°C) Propylene conversion rate (mol%) Acrolein + acrylic acid total yield ( Molar %) Acrolein + Acrylic Total Selectivity (% by mole) Example 1 Catalyst (1) / Catalyst (2) = 100 310 98.5 9L7 93.1 1500mm / 1500mm 4000 315 98.3 92.6 94.2 Comparative Example 1 Catalyst (1) =3000mm 100 310 98.4 91.8 93.3 4000 314 98.3 910 93.6 Comparative Example 2 Catalyst (2) = 3000 mm 100 310 98.5 91.5 92.9 4000 322 98.1 92.1 93.9 Example 2 Catalyst (3) Brain media (1) = 100 310 97.8 91.3 93.4 1000mm/2000mm 4000 316 97.9 91.7 93.7 Comparative Example 3 Catalyst (4) Brain Media (1) = 100 310 97.7 90.9 93.0 1000mm/2000mm 4000 321 97.6 90.9 93.1 Comparative Example 4 Catalyst (5) / Catalyst (1) = 100 310 97.8 90.7 92.7 1000mm/2000mm 4000 323 97.6 90.6 92.8 Example 3 Catalyst (6) / Catalyst (1) = 100 320 97.6 89.5 91.7 1000mm/2000mm 4000 334 97.7 89.8 91.9 Example 4 Catalyst (9) / Catalyst (1) / Catalyst 100 320 99.0 91.0 91.9 (7)=1000mm/1400mm/600mm 4000 329 99.2 91.2 91.9 Compare 5 Catalyst (10) / Catalyst (1) / Catalyst 100 310 99.2 90.5 91.2 (8) = 1000mm / 1400mm / 600mm 4000 337 99.0 89.8 90.8 Example 5 Catalyst (1) / Catalyst (9) / Catalyst 100 310 99.2 90.6 91.3 (2)=200mm/900mm/1900mm 4000 334 99.0 90.8 91.7 (26) 1247628 [Effects of the Invention] According to the present invention, it is based on a fixed bed multitubular reactor using a molybdenum-based catalyst. In the case of contacting an oxidation reaction to produce an unsaturated aldehyde and/or an unsaturated carboxylic acid, the deterioration of the catalyst at the hot spot can be suppressed, and it does not depend on where the hot spot occurs, and the raw material gas In the case where the concentration is high, the reaction can be continued for a long period of time while maintaining high yield.

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Claims (1)

J2_7, 6 霸, 拾, patent application scope 1. A method for producing an unsaturated aldehyde and/or an unsaturated carboxylic acid, which is a fixed-bed multi-tubular reactor using a ruthenium-charged catalyst, and is made of propylene or different At least one compound selected from the group consisting of butyl alcohol, tert-butanol, and methyl tert-butyl ether is used as a raw material, and is subjected to vapor phase contact oxidation by molecular oxygen or a gas containing molecular oxygen to produce an unsaturated aldehyde of a corresponding raw material. And/or an unsaturated carboxylic acid characterized in that the catalyst is an oxide and/or a composite oxide containing molybdenum, ruthenium and iron as essential components, and each reaction tube of a Kawasaki® fixed bed multitubular reactor Internally, a plurality of reaction bands are divided in the tube axis direction, and in each reaction zone, the apparent density ratio R of the catalyst relative to the true density of the catalyst is respectively added (the apparent density of the catalyst/the true of the catalyst) Density) is a different catalyst. 2. The method for producing an unsaturated aldehyde and/or an unsaturated citric acid according to claim 1 in the plurality of reaction zones, wherein the gas inlet side of each reaction tube faces the gas outlet side. Filling R is a smaller and smaller catalyst for R. 3) An unsaturated aldehyde and/or an unsaturated acid as in claim 1 of the patent application; wherein the catalyst activity in the plurality of reaction zones is different. 4. The method for producing an unsaturated aldehyde and/or an unsaturated residual acid according to item 3 of the patent application, in which the gas is supplied from the side of each reaction tube toward the gas outlet side in the plurality of reaction zones. The activity is increasing and the activity is different. -31 - (2) 1247628 5. A method of producing an unsaturated aldehyde and/or an unsaturated carboxylic acid according to claim 1, wherein the number of the reaction bands is 2 or 3. -32·