JP5059702B2 - Method for producing catalyst for producing unsaturated carboxylic acid - Google Patents

Description

  The present invention relates to a method for producing a catalyst for producing an unsaturated carboxylic acid containing at least molybdenum and vanadium, which is used for producing an unsaturated carboxylic acid by vapor-phase catalytic oxidation of an unsaturated aldehyde using molecular oxygen.

  Conventionally, many proposals have been made on a catalyst used for producing an unsaturated carboxylic acid by vapor-phase catalytic oxidation of an unsaturated aldehyde and a production method thereof.

  Many of such catalysts have a composition containing at least molybdenum and vanadium, and a shaped catalyst having such a composition is industrially used. These are classified into extrusion molding catalysts, supported molding catalysts, and the like according to the molding method. Usually, an extrusion-molded catalyst is produced through a process of kneading particles containing a catalyst component and extrusion molding, and a supported molded catalyst is produced through a process of supporting a powder containing a catalyst component on a carrier.

  With regard to the extrusion molding catalyst, for example, a method of improving physical strength and selectivity by adding graphite during production (Patent Document 1), extrusion molding using two types of organic binders, hydroxypropylmethylcellulose and curdlan. A catalyst production method (Patent Document 2) and the like have been proposed.

However, the catalysts obtained by these known methods are not necessarily sufficient as industrial catalysts in terms of physical properties, catalytic activity, target product selectivity, and generally further improvements are desired from industrial knowledge.
JP-A-60-150834 JP 2002-282696 A

  An object of this invention is to provide the manufacturing method of the catalyst for unsaturated carboxylic acid manufacture which was excellent in the selectivity and yield of unsaturated carboxylic acid, and was excellent in the mechanical strength of a catalyst molded object.

  The present invention relates to a method for producing a molded catalyst containing at least molybdenum and vanadium, which is used for producing an unsaturated carboxylic acid by vapor-phase catalytic oxidation of an unsaturated aldehyde with molecular oxygen, and particles containing a catalyst component And adding a polymer containing a glucose unit and a mannose unit to form a unsaturated carboxylic acid production catalyst.

  The catalyst obtained by the method of the present invention is used for producing an unsaturated carboxylic acid by using an unsaturated aldehyde as a reaction raw material and subjecting the reaction raw material to gas phase catalytic oxidation with molecular oxygen. The unsaturated carboxylic acid production catalyst obtained by the method of the present invention is excellent in mechanical strength. By using this catalyst, the unsaturated carboxylic acid can be produced with high selectivity and yield.

  A catalyst produced by the method of the present invention (hereinafter referred to as “catalyst”) is obtained by subjecting a reaction raw material to gas phase catalytic oxidation using molecular oxygen, and an unsaturated aldehyde corresponding to the reaction raw material, for example, acrolein to acrylic acid, Used when producing methacrylic acid from methacrolein.

  The catalyst component includes at least molybdenum and vanadium. In addition, iron, cobalt, chromium, aluminum, strontium, germanium, boron, arsenic, selenium, silver, silicon, sodium, tellurium, lithium, antimony, phosphorus , Potassium, barium, magnesium, titanium, manganese, copper, zinc, zirconium, niobium, tungsten, tantalum, calcium, tin, bismuth, gallium, cerium, lanthanum, rubidium, cesium, thallium, and the like.

  Such a shaped catalyst containing at least molybdenum and vanadium is generally obtained by (1) a step of producing particles containing a catalyst component, (2) a step of kneading particles containing the obtained catalyst component, etc. (3) obtained. It is manufactured through a process of extruding the kneaded product, and a process of (4) drying and / or heat treatment.

  In the present invention, the step (1) is not particularly limited, and various conventionally known methods can be applied. Usually, an aqueous slurry containing at least molybdenum and vanadium is dried, and further pulverized as necessary to form particles. To.

  The method for preparing an aqueous slurry containing at least molybdenum and vanadium is not particularly limited, and various methods such as precipitation methods and oxide mixing methods that are well known in the art are used unless significant uneven distribution of catalyst components is involved. Can do.

  As starting materials for the catalyst components, oxides, sulfates, nitrates, carbonates, hydroxides, ammonium salts, halides, and the like of each element can be used. For example, examples of the molybdenum raw material include ammonium paramolybdate and molybdenum trioxide. As the starting material for the catalyst component, one kind of each element may be used alone, or two or more kinds may be used in combination.

  The method of drying the aqueous slurry to form particles is not particularly limited. For example, the drying method using a spray dryer, the drying method using a slurry dryer, the drying method using a drum dryer, and evaporation. A method of pulverizing a lump of dried product by drying can be applied. Among these, it is preferable to obtain dry particles using a spray dryer because particles are obtained simultaneously with drying and the obtained particles are spherical. Although the drying conditions vary depending on the drying method, when a spray dryer is used, the inlet temperature is usually 100 to 500 ° C and the outlet temperature is usually 100 ° C or higher, preferably 105 to 200 ° C.

  The dry particles thus obtained may be heat-treated (fired) preferably at 200 to 500 ° C., if necessary. Although the calcination conditions are not particularly limited, the calcination is usually performed under a flow of oxygen, air or nitrogen, and the calcination time may be appropriately selected depending on the target catalyst.

  Next, in the step (2), a mixture of particles containing the catalyst component obtained in the step (1), a liquid, and a polymer containing glucose units and mannose units is kneaded.

  The apparatus used for kneading is not particularly limited. For example, a batch-type kneading machine using a double-arm type stirring blade, a continuous kneading machine such as a shaft rotation reciprocating type or a self-cleaning type can be used. However, the batch method is preferable because kneading can be performed while checking the state of the kneaded product. Moreover, the end point of kneading | mixing can be judged by visual observation or a touch normally.

  The mixing method of the said particle | grains, a liquid, and the polymer containing a glucose unit and a mannose unit is not specifically limited. Specifically, a method of mixing particles and a mixture of a polymer containing glucose units and mannose units and a liquid, a solution or slurry containing a catalyst component, and a method of mixing a polymer containing glucose units and a mannose unit Examples thereof include a method of mixing a particle containing a polymer containing glucose units and mannose units in a liquid, and a method of mixing particles and a polymer containing particles and glucose units and mannose units. A method of mixing liquids is preferred.

  The liquid used in the step (2) is preferably water or alcohol. Examples of such alcohol include lower alcohols such as ethyl alcohol, methyl alcohol, propyl alcohol, and butyl alcohol. Among these, water is particularly preferable from the viewpoints of economy and handleability. These liquids may be used alone or in combination of two or more.

  The amount of the liquid used is appropriately selected depending on the properties of the particles containing the catalyst component, the type of the liquid, and the like, but is usually 10 to 70 with respect to 100 parts by mass of the dry particles or calcined particles obtained in the step (1). It is a mass part, Preferably it is 20 mass parts or more or 60 mass parts or less.

  The polymer containing a glucose unit and a mannose unit used in the step (2) is a polysaccharide in which glucose and mannose are polymerized by a glycosidic bond, and an example thereof is glucomannan. The origin of the polymer containing glucose units and mannose units is not particularly limited, but those of microbial origin, plant origin and animal origin are preferred. Polymers containing these glucose units and mannose units have water retention and high viscosity, and can contain more water in the molded body, so that finally preferable pores are expressed in the catalyst and more selection is made. A highly efficient catalyst can be produced. A 1% aqueous solution and a viscosity at 20 ° C. of 30,000 mPa · s or more are preferable because they improve the moldability.

  A polymer containing a glucose unit and a mannose unit may be used unpurified or may be used after purification, but a metal or an ignition residue as an impurity may deteriorate catalyst performance. Less is preferred.

  The amount of the polymer containing the glucose unit and the mannose unit is appropriately selected depending on the kind and size of the particles containing the catalyst component, the kind of the liquid, etc. Usually, the catalyst component obtained in the step (1) is used. It is 0.05-15 mass parts with respect to 100 mass parts of containing particles, Preferably it is 0.1 mass part or more or 10 mass parts or less, More preferably, it is 0.2 mass part or more or 8 mass parts or less. . As the amount of the polymer containing glucose units and mannose units increases, moldability tends to improve, and as the amount decreases, post-treatment such as heat treatment after molding tends to become easier. The shape at the time of using the polymer containing a glucose unit and a mannose unit may be in a powder state or a paste state.

  In the step (2), a molding aid can be used together with the polymer containing a glucose unit and a mannose unit as described above. In the present invention, when a β-glucan derivative is used as a molding aid together with the polymer, a catalyst having further excellent activity and selectivity can be obtained.

  In the present invention, the β-glucan derivative refers to a polysaccharide composed of glucose in which glucose is bound in a β-type structure, β-1,4-glucan, β-1,3-glucan, β Examples include derivatives such as -1,6-glucan and β-1,3-1,6-glucan β-1,3-1,4-glucan.

  Examples of such β-glucan derivatives include methyl cellulose, ethyl cellulose, carboxymethyl cellulose, sodium carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl methyl cellulose, hydroxybutyl methyl cellulose, ethyl hydroxyethyl cellulose and the like, fermentation Examples thereof include β-1,3-glucan such as β-glucan, curdlan, laminaran, paramylon, callose, Pakiman, and scleroglucan. One or more β-glucan derivatives may be used. A 1% aqueous solution and a viscosity in the range of 10 to 15000 mPa · s at 20 ° C. are preferable because of good moldability.

  The amount of the β-glucan derivative used is appropriately selected depending on the type and size of the particles containing the catalyst component, the type of the liquid, etc. Usually, 100 parts by mass of the particles containing the catalyst component obtained in the step (1) It is 0.05-15 mass parts with respect to this, Preferably it is 0.1 mass part or more or 10 mass parts or less, More preferably, it is 0.2 mass part or more or 8 mass parts or less. As the amount of β-glucan derivative added increases, moldability tends to improve, and as the amount decreases, post-treatment such as heat treatment after molding tends to be simplified.

  The total amount of the polymer containing the glucose unit and mannose unit and the β-glucan derivative is usually 0.2 parts by mass or more with respect to 100 parts by mass of the particles containing the catalyst component obtained in the step (1). Preferably, 0.4 parts by mass or more is more preferable, 20 parts by mass or less is preferable, and 16 parts by mass or less is more preferable.

  Next, in the step (3), the kneaded product obtained in the step (2) is extruded. When performing extrusion molding, an auger type extrusion molding machine, a piston type extrusion molding machine, or the like can be used. The shape of the molded body by extrusion molding is not particularly limited, and it can be molded into an arbitrary shape such as a ring shape, a columnar shape, a honeycomb shape, or a star shape.

  Next, in the step (4), the catalyst molded body obtained in the step (3) is dried and calcined to obtain a catalyst (product). The drying method is not particularly limited, and a generally known method such as hot air drying, humidity drying, far-infrared drying, or microwave drying can be arbitrarily used. The drying conditions can be appropriately selected as long as the desired moisture content can be achieved.

  The dried molded article is usually fired, but may be omitted if the particles containing the catalyst component are fired in the step (1). There are no particular limitations on the firing conditions, and known firing conditions can be applied. Usually, it is performed in a temperature range of 200 to 600 ° C. The drying step may be omitted and only firing may be performed.

  In the present invention, conventionally known inorganic compounds such as graphite and diatomaceous earth, glass fibers, inorganic fibers such as ceramic fibers and carbon fibers, and the like can be added. The addition may be performed at the time of kneading in the step (2).

  Examples of the production of unsaturated carboxylic acids by gas phase catalytic oxidation of unsaturated aldehydes using the catalyst of the present invention include the production of acrylic acid by oxidation of acrolein and the production of methacrylic acid by oxidation of methacrolein. .

  As a catalyst suitable for the production of acrylic acid by oxidation of acrolein, a catalyst having a composition represented by the following general formula (I) is preferably exemplified.

_{Mo a V b X1 c Y1 d} Z1 e O f (I)
(Wherein Mo, V and O represent molybdenum, vanadium and oxygen, respectively, X1 represents at least one element selected from the group consisting of iron, cobalt, chromium, aluminum and strontium, Y1 represents germanium, boron, Arsenic, Selenium, Silver, Silicon, Sodium, Tellurium, Lithium, Antimony, Phosphorus, Potassium and Barium indicate at least one element selected from the group consisting of magnesium, titanium, manganese, copper, zinc, zirconium, At least one element selected from the group consisting of niobium, tungsten, tantalum, calcium, tin, and bismuth, wherein a, b, c, d, e, and f represent the atomic ratio of each element; When b = 0.01 to 6, c = 0 to 5, d = 0 to 10, e = 0 to 5, and f is the original of each component An oxygen atom ratio required for satisfying the valence).

  Moreover, as a catalyst suitable for manufacture of methacrylic acid by oxidation of methacrolein, a catalyst having a composition represented by the following general formula (II) is preferably exemplified.

_{P g Mo h V i Cu j} X2 k Y2 l Z2 m O n (II)
(Wherein P, Mo, V, Cu and O represent phosphorus, molybdenum, vanadium, copper and oxygen, respectively, X2 is antimony, bismuth, arsenic, germanium, zirconium, tellurium, selenium, silicon, tungsten, boron and silver. Y2 represents at least one element selected from the group consisting of iron, zinc, chromium, magnesium, tantalum, manganese, cobalt, barium, gallium, cerium, and lanthanum Z2 represents at least one element selected from the group consisting of potassium, rubidium, cesium and thallium, and g, h, i, j, k, l, m and n represent the atomic ratio of each element. When h = 12, g = 0.5-3, i = 0.01-3, j = 0-2, k = 0-3, l = 0-3, m = 0.01-3 There, n represents an oxygen atom ratio required for satisfying the valency of each component.)

  In the presence of the catalyst produced by the method of the present invention, an unsaturated carboxylic acid can be produced by gas phase catalytic oxidation of a raw material gas containing acrolein as a reaction raw material or methacrolein and molecular oxygen. The reaction is usually carried out in a fixed bed. The catalyst layer may be one layer or two or more layers. At this time, in the reaction tube, the catalyst may be diluted with an inert carrier such as silica, alumina, silica-alumina, silicon carbide, titania, magnesia, ceramic balls or stainless steel. Moreover, you may add these inert support | carriers at the time of the process of (2) and kneading | mixing. At this time, the concentration of the unsaturated aldehyde in the reaction gas can be varied within a wide range, but is preferably 1 to 20% by volume, particularly preferably 3 to 10% by volume.

  The raw material unsaturated aldehyde may contain a small amount of impurities such as water and lower saturated aldehyde, and these impurities do not substantially affect the reaction. Although it is economical to use air as the molecular oxygen source, air or the like enriched with pure oxygen can also be used as necessary. The oxygen concentration in the raw material gas is defined by a molar ratio (volume ratio) to the unsaturated aldehyde, and this value is preferably 0.3 to 4, particularly 0.4 to 2.5.

  The raw material gas preferably contains water in addition to the reaction raw material and molecular oxygen, and is preferably diluted with an inert gas such as nitrogen or carbon dioxide. The concentration of water in the source gas is preferably 3 to 45% by volume. The reaction pressure is preferably from normal pressure to several hundred kPa. The reaction temperature can usually be selected in the range of 200 to 430 ° C, but the range of 220 to 400 ° C is particularly preferable. The contact time is preferably 1.5 to 15 seconds.

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples.

  “Part” in Examples and Comparative Examples is part by mass, and a kneader equipped with a batch type double-arm type stirring blade was used for kneading. The analysis of the raw material gas and the reaction gas was performed by gas chromatography. The catalyst composition was determined from the amount of catalyst raw material charged. Moreover, the viscosity of the polymer containing a glucose unit and a mannose unit and a β-glucan derivative was measured with a B-type viscometer using a 1% aqueous solution or dispersion.

  The reaction rate of the raw material unsaturated aldehyde in the examples and comparative examples (hereinafter referred to as the reaction rate) and the selectivity of the unsaturated carboxylic acid to be produced were calculated by the following equations.

Reaction rate (%) = A / B × 100
Selectivity of unsaturated carboxylic acid (%) = C / A × 100
Unsaturated carboxylic acid yield (%) = C / B × 100
Here, A is the number of moles of reacted raw material unsaturated aldehyde, B is the number of moles of supplied raw material unsaturated aldehyde, and C is the number of moles of unsaturated carboxylic acid produced.

  Moreover, the filling powder ratio of the catalyst molded body is defined as follows.

  The catalyst molded body a is filled from a stainless steel pipe upper part into a stainless steel pipe having an inner diameter of 30 mmφ and a length of 5 m installed perpendicularly to the horizontal direction, and is recovered from the lower part of the stainless steel pipe after filling. When the catalyst molded body that does not pass through the 8-mesh sieve in the recovered catalyst molded body is part b, the filling powderization rate is expressed by the following equation.

Filling powder rate (%) = {(ab) / a} × 100

The compressive strength was measured by the following methods.
Compressive strength: Small material testing machine manufactured by Fujii Seiki Co., Ltd. Measured with FSP-100, and the average compressive strength is an average value obtained by measuring 30 molded bodies.

Example 1
100 parts of molybdenum trioxide, 3.2 parts of vanadium pentoxide, 0.4 part of boric acid, 3.8 parts of antimony pentoxide and 10.0 parts of 85% phosphoric acid were mixed with 800 parts of pure water. This was heated and stirred under reflux for 3 hours, 2.8 parts of copper nitrate and 0.9 parts of cobalt oxide were added, and the mixture was again heated and stirred under reflux for 2 hours. The slurry was cooled to 50 ° C., a solution obtained by dissolving 10.1 parts of cesium bicarbonate in 30 parts of pure water was added, and the mixture was stirred for 15 minutes. Next, 10 parts of ammonium nitrate dissolved in 30 parts of pure water was added and stirred for 15 minutes. And the slurry containing the obtained catalyst component was made into the particle | grains containing the catalyst component of an average particle diameter of 80 micrometers using the spray dryer.

  To 100 parts of the particles containing the catalyst component thus obtained, 5 parts of glucomannan having a viscosity (1% aqueous solution, viscosity at 20 ° C.) of 190,000 mPa · s was added and dry-mixed. 50 parts of pure water was mixed here, kneaded until it became a clay-like substance using a batch-type kneader having a double-armed stirring blade, and then extruded using an auger-type extruder, and the outer diameter A catalyst molded body having a diameter of 6 mm, an inner diameter of 1 mm, and a length of 5 mm was obtained.

  The obtained catalyst molded body was dried at 130 ° C. for 6 hours and then heat-treated at 380 ° C. for 5 hours under air flow to obtain a final fired product.

The composition of the elements other than oxygen in the resulting molded catalyst is
P _1.5 Mo ₁₂ V _0.6 Cu _0.2 B _0.1 Sb _0.4 Co _0.2 Cs _0.9
Met.

  This formed catalyst is filled in a stainless steel reaction tube, using a raw material gas of 5% methacrolein, 10% oxygen, 30% water vapor and 55% nitrogen (volume%) under normal pressure, contact time 3.6 seconds, reaction temperature. The reaction was performed at 270 ° C. The results are shown in Table 1.

(Example 2)
In Example 1, in place of 5 parts of glucomannan, Example 1 except that 3 parts of glucomannan and 2 parts of hydroxypropylmethylcellulose having a viscosity (1% aqueous solution, viscosity at 20 ° C.) of 15000 mPa · s were added. A catalyst molded body was produced and reacted in the same manner as described above. The results are shown in Table 1.

(Example 3)
In Example 1, instead of 5 parts of glucomannan, the same as Example 1 except that 3 parts of glucomannan and 2 parts of curdlan having a viscosity (1% aqueous solution, viscosity at 20 ° C.) of 40 mPa · s were added. A catalyst molded body was produced and reacted. The results are shown in Table 1.

Example 4
In Example 1, instead of 5 parts of glucomannan, 2 parts of glucomannan and 2 parts of hydroxypropylmethylcellulose having a viscosity (1% aqueous solution, viscosity at 20 ° C.) of 15000 mPa · s and viscosity (1% aqueous solution at 20 ° C.) A catalyst molded body was produced and reacted in the same manner as in Example 1 except that 1 part of curdlan having a viscosity of 40 mPa · s was added. The results are shown in Table 1.

(Example 5)
In Example 1, in place of 5 parts of glucomannan, Example 1 except that 2 parts of glucomannan and 3 parts of hydroxypropylmethylcellulose having a viscosity (1% aqueous solution, viscosity at 20 ° C.) of 4000 mPa · s were added. A catalyst molded body was produced and reacted in the same manner as described above. The results are shown in Table 1.

(Comparative Example 1)
In Example 1, a catalyst molded body was produced and reacted in the same manner as in Example 1 except that only 40 parts of pure water was added to 100 parts of the obtained catalyst calcined product without adding glucomannan. It was. The obtained molded body had a very low shape retention. The results are shown in Table 1.

(Comparative Example 2)
In Example 1, instead of 5 parts of glucomannan, 4 parts of hydroxypropyl methylcellulose having a viscosity (1% aqueous solution, viscosity at 20 ° C.) of 15000 mPa · s and a viscosity (1% aqueous solution, viscosity at 20 ° C.) of 40 mPa · s. A catalyst molded body was produced and reacted in the same manner as in Example 1 except that 1 part of s curdlan was added. The results are shown in Table 1.

(Comparative Example 3)
In Example 1, instead of 5 parts of glucomannan, a catalyst molded body was produced and reacted in the same manner as in Example 1 except that 5 parts of silica sol having an average particle diameter of 5 to 9 nm was added as silicic anhydride. . The results are shown in Table 1.

Claims (4)

  A method for producing a molded catalyst containing at least molybdenum and vanadium, which is used when producing an unsaturated carboxylic acid by vapor-phase catalytic oxidation of an unsaturated aldehyde with molecular oxygen, comprising a unit of glucose in particles containing a catalyst component And a polymer containing a mannose unit is added to form a catalyst for producing an unsaturated carboxylic acid.   The method for producing a catalyst according to claim 1, wherein the catalyst component is formed by adding a polymer containing a glucose unit and a mannose unit and a β-glucan derivative to particles containing the catalyst component.   The method for producing a catalyst according to claim 1 or 2, wherein the polymer is glucomannan.   The method for producing a catalyst according to claim 2, wherein the β-glucan derivative is at least one of methylcellulose, carboxymethylcellulose, hydroxypropylmethylcellulose, hydroxyethylmethylcellulose, and β-1,3-glucan.