JP6487242B2 - Method for producing acrylic acid production catalyst, catalyst therefor, and method for producing acrylic acid using the catalyst - Google Patents

Description

  The present invention relates to a method for producing a catalyst suitable for producing acrylic acid by catalytic gas phase oxidation of propane and / or acrolein in the presence of molecular oxygen or a molecular oxygen-containing gas, and the catalyst, and the catalyst. Related to the production of acrylic acid.

  Acrylic acid is industrially important as a raw material for various synthetic resins, paints, and plasticizers, and in recent years, its importance as a raw material for water-absorbing resins is increasing. Generally, acrylic acid is produced by catalytic vapor phase oxidation of propylene in the presence of molecular oxygen or a molecular oxygen-containing gas to produce acrolein, and the resulting acrolein is converted to molecular oxygen or a molecular oxygen-containing gas. It is produced by a two-stage oxidation method in which it is subjected to catalytic gas phase oxidation to acrylic acid in the presence of.

  As another production method, in order to reduce the production cost of acrylic acid, in recent years, a method using propane, which is cheaper than propylene, as a raw material has been developed, and propane is molecular oxygen or molecular oxygen. Various proposals have also been made for a method of catalytic vapor phase oxidation to acrylic acid in a single step in the presence of a contained gas.

  As a catalyst for producing acrylic acid by catalytic gas phase oxidation of propane and / or acrolein in the presence of molecular oxygen or molecular oxygen-containing gas, composite oxidation centered on molybdenum-vanadium system However, catalyst performance such as selectivity and yield of the target acrylic acid is not always satisfactory, and various proposals have been made by various companies for the purpose of improving the catalyst performance. Has been.

  For example, in Patent Document 1, the starting material mixture is spray-dried and then calcined at 400 ° C., and the liquid binder is 20 to 90% by weight of water, and the boiling point or sublimation temperature at normal pressure is 100 ° C. A method of supporting a carrier using a solution composed of 10 to 80% by weight of a higher organic compound is disclosed.

  In Patent Document 2, an aqueous solution or aqueous dispersion containing a catalytically active element or a compound thereof is dried, the obtained dry powder is fired, and the obtained powder of the catalytically active component is converted into diols or triols. A method is disclosed in which the carrier is supported on a carrier by a rolling granulator using the binder as a binder.

  In Patent Document 3, a source compound of each component element is integrated in the presence of an organic acid in an aqueous medium system, and an aqueous solution or dispersion of the resulting integrated product is dried to prepare a powder. A method for firing the molded article is disclosed.

JP-A-8-252464 JP-A-8-299797 JP-A-2005-305421

  Acrylic acid is currently produced on a scale of millions of tons / year worldwide, and even if it is 0.1%, if the yield is improved on an industrial scale, a very large economic advantage is brought about. Therefore, further improvement in acrylic acid yield and high productivity are desired as industrial practical catalysts.

  Thus, an object of the present invention is to provide a catalyst production method suitable for producing acrylic acid excellent in catalyst performance such as catalyst activity and selectivity and catalyst life when producing acrylic acid from propane and / or acrolein. An object of the present invention is to provide a catalyst and a method for producing acrylic acid using the catalyst.

  As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention have developed propane and / or acrolein containing molybdenum and vanadium as essential components in the presence of molecular oxygen or a molecular oxygen-containing gas. A method for producing a catalyst for producing acrylic acid by oxidation, and it has been found that the above problems can be easily solved by adding an amino acid, and the present invention has been achieved.

  According to the present invention, by solving the above problems, a catalyst that can be stably produced in a high yield over a long period of time when producing acrylic acid by catalytic gas phase oxidation of propane and / or acrolein with molecular oxygen is provided. Acrylic acid can be produced in a high yield over a long period of time using the catalyst.

  Hereinafter, although the manufacturing method of the catalyst concerning this invention and the manufacturing method of acrylic acid using this catalyst are demonstrated in detail, the scope of the present invention is not restrained by these description, and it is not limited to the following illustrations. The present invention can be changed and implemented as appropriate without departing from the spirit of the invention.

The catalyst for producing acrylic acid produced in the present invention is preferably represented by the following general formula (1) as the composition of the catalytically active component.
MoaVbWcAdBeCfDgOh (1)
(Wherein Mo is molybdenum, V is vanadium, W is tungsten, A is at least one element selected from antimony and tin, B is chromium, manganese, iron, cobalt, nickel, copper, zinc, bismuth, tellurium and At least one element selected from niobium, C is at least one element selected from alkali metals and alkaline earth metals, D is at least one element selected from silicon, aluminum, titanium, zirconium and cerium, and O Is oxygen, a, b, c, d, e, f, g and h represent the number of atoms of Mo, V, W, A, B, C, D and O, and when a = 12, 2 ≤ b ≤ 14, 0 ≤ c ≤ 10, 0 ≤ d ≤ 5, 0 ≤ e ≤ 12, 0 ≤ f ≤ 5, 0 ≤ g ≤ 50, and h is a numerical value determined by the oxidation state of each element. )
As the catalytic active component, raw materials generally used for this kind of preparation can be used. For example, oxides, hydroxides, ammonium salts, nitrates, carbonates, sulfates, organic acid salts of the respective elements, etc. These salts, aqueous solutions or sols thereof, or compounds containing a plurality of elements can also be used.

  A starting material mixture is prepared by dissolving or suspending these starting materials in a solvent such as water (hereinafter, referred to as “raw material mixture preparation step”). The preparation method at that time is for the production of this type of catalyst, such as a method of sequentially mixing the above starting materials into water or a method of preparing a plurality of aqueous solutions or aqueous slurries according to the type of starting materials and sequentially mixing them. What is necessary is just to prepare by the method generally used. There is no restriction | limiting in particular about the mixing order of starting materials, temperature, pressure, pH, etc., According to a starting material, it can select suitably. Moreover, it is preferable to control pH within the range of 4-10, adding nitrogen-containing compounds, such as nitric acid, ammonia, ammonium nitrate, and ammonium carbonate suitably.

  Next, the obtained starting raw material mixture is dried to obtain a dried product (hereinafter also referred to as “catalyst precursor”) (hereinafter, sometimes referred to as “raw material mixture drying step”). Specifically, a method of obtaining a powdery dried product using a spray dryer, a drum dryer or the like, a block-type or flake-type dried product heated in an air stream using a box-type dryer, a tunnel-type dryer or the like And a method of once concentrating the starting raw material mixture and evaporating to dryness to obtain a cake-like solid, and further subjecting this solid to the above heat treatment. Moreover, as a drying method by reduced pressure, for example, using a vacuum dryer, a block or powdery dried product can be obtained.

  The obtained dried product is sent to a subsequent molding step through a pulverization step and a classification step for obtaining a powder having an appropriate particle size as required. The powder particle size of the dried product at that time is not particularly limited, but is preferably 500 μm or less, preferably 200 μm or less, and more preferably 100 μm or less in terms of excellent moldability.

  In a molding process for molding a dried product (hereinafter, sometimes simply referred to as “molding process”), as a molding method, a molding method in which a fixed shape is formed by a tableting molding machine or an extrusion molding machine, or a certain shape is used. Examples thereof include a granulation method in which the particles are supported on an arbitrary inert carrier. In addition, the starting raw material mixture can be used in a liquid state without being dried, and can be produced by an evaporation-drying method in which the starting material mixture is absorbed or applied to a desired carrier while being heated for a long time and dried. Among these, a granulation method for supporting on an inert carrier using a centrifugal fluidized coating method described in JP-A-63-200249 or a rocking mixer method described in JP-A-2004-136267 is particularly preferred. preferable.

  In the case of a molding method using a tableting machine or an extrusion molding machine, the shape is not particularly limited, and may be any shape such as a spherical shape, a cylindrical shape, a ring shape, and an indeterminate shape. Of course, in the case of a spherical shape, it does not need to be a true sphere, and may be substantially spherical, and the same applies to a cylindrical shape and a ring shape.

Examples of inert carriers that can be used in the granulation method and evaporation to dryness method include alumina, silica, silica-alumina, titania, magnesia, steatite, cordierite, silica-magnesia, silicon carbide, silicon nitride, and zeolite. Can be mentioned. There is no restriction | limiting in particular also in the shape, The thing of well-known shapes, such as spherical shape, cylinder shape, and ring shape, can be used.
In these molding processes, molding aids and binders for improving the moldability of the dried product, pore forming agents for forming appropriate pores in the catalyst, etc. are generally aimed at producing these effects. (Hereinafter sometimes referred to as “auxiliary substance”) can be used, and among these, it is preferable to use a binder in the granulation method.

  Specific examples of the auxiliary substances include water, methanol, propyl alcohol, ethylene glycol, glycerin, erythritol, benzyl alcohol, butyl alcohol, phenol and other alcohols having 1 to 7 carbon atoms, oxalic acid, propionic acid, maleic acid. And organic acids having 1 to 7 carbon atoms such as benzoic acid and lactic acid, and nitrogen-containing compounds such as nitric acid, ammonia, ammonium nitrate, urea and ammonium carbonate. These may be used alone, but two or more are preferably used in combination, and particularly preferably used as a mixed solution with water.

  These auxiliary substances are not limited to the molding step, and can be used, for example, in the raw material mixture preparation step and the raw material mixture drying step. Specifically, it is added to the starting material mixture in the starting material mixture preparation step, or to the starting material mixture before drying or in the middle of drying in the starting material mixture drying step, or to the obtained dried product. A method is mentioned.

  In addition to the auxiliary substance, a reinforcing agent can be used for the purpose of improving the mechanical strength of the catalyst. Specific examples include silica, alumina, ceramic fiber, glass fiber, carbon fiber, mineral fiber, metal fiber, various whiskers such as silicon carbide and silicon nitride, which are generally known as reinforcing agents, and the like. The crystal structure may be polycrystalline, monocrystalline or amorphous. A plurality of reinforcing agents having different fiber diameters, fiber lengths, materials, and the like may be used depending on the shape and mechanical strength of the catalyst. The reinforcing agent may be added to the starting raw material mixture, or may be blended during the molding process.

  The molded body or carrier obtained in the molding process is sent to the subsequent firing process. The firing temperature is 360 ° C to 440 ° C, more preferably 380 ° C to 420 ° C. The firing time is preferably 1 to 24 hours, more preferably 1 to 10 hours. The firing furnace is not particularly limited, and a generally used box-type firing furnace or tunnel-type firing furnace may be used.

  The present invention is characterized in that an amino acid is added in the above-described catalyst production method. There are no particular restrictions on the location where the amino acid is added, but it is preferably added in any of the raw material mixture preparation step, raw material mixture drying step and molding step described above.

  By adding an amino acid, it is presumed that in the calcination step, it has some influence on the formation of the calcination atmosphere that contributes to the improvement of the catalyst performance. Therefore, it is preferable that the added amino acid remains sufficiently in the catalyst molded body or the support body at the start of the firing step. In addition, also in the above-mentioned auxiliary substance, like the amino acid, it may remain in the catalyst molded body or the support before the start of the calcination step.

The preferred amino acid addition conditions are complex factors that depend on the type and concentration of the amino acid, the amount to the catalytically active component, the heating rate in the firing process, the oxygen concentration in the furnace, etc. Although it is not possible, it is as follows.
Examples of the amino acid added in the production process of the catalyst include glutamic acid, lysine, arginine and the like. In particular, amino acids having 2 to 4 carbon atoms are suitable, and specific examples thereof include glycine, alanine, threonine and the like.

  The amino acid can be added directly to the starting material mixture, for example, or the amino acid can be dissolved once in the liquid and added as an amino acid solution in each step, but the auxiliary substance used in the molding step A method in which an amino acid is added to the solution and the amino acid is added together with the auxiliary substance is preferable.

  The amino acid concentration of these amino acid-containing liquids is preferably 0.5 to 25% by mass, more preferably 1 to 20% by mass. Moreover, 0.01-10 mass% is preferable as an addition mass ratio of the amino acid with respect to the theoretical mass (oxide conversion) of the catalytically active component after baking, Furthermore, the range of 0.05-5 mass% is preferable.

  Further, the rate of temperature rise in the firing step is preferably 0.1 ° C./min to 15 ° C./min, and generally about 1 ° C./min. When the rate of temperature increase is 15 ° C./min or more, amino acids are rapidly exothermic and decomposed, so that the performance tends to decrease due to thermal degradation of the catalyst due to the heat generation. When the rate of temperature increase is 0.1 ° C./min or less, the temperature increase time becomes long, the vaporization and decomposition of amino acids become slow, and it becomes difficult to form an appropriate calcination atmosphere, so that the catalyst performance tends to decrease. The oxygen concentration is preferably calcined in a low oxygen concentration region of 20% by volume or less, and when the amino acid concentration of the amino acid-containing liquid is low, a lower oxygen concentration region tends to be preferable.

In addition, it is preferable that the dry matter used at a formation process has a weight loss rate in 5-40 mass%. Here, the weight loss rate of the dried product is calculated from the following equation based on the mass change before and after heating, by heating the sample in an air atmosphere at 300 ° C. until there is no mass change.
Weight loss (mass%) = [(mass before heating dried product (g) −mass after heating dried product (g)) / mass before heating dried product (g)] × 100
The reactor used for producing acrylic acid by catalytic gas phase oxidation of propane and / or acrolein with molecular oxygen using the catalyst for producing acrylic acid of the present invention is not particularly limited, and is a fixed bed reactor. Either a fluidized bed reactor or a moving bed reactor can be used, but a fixed bed reactor is usually used.

  When the catalyst is charged into the reactor, it is not necessary to be a single catalyst. For example, a plurality of types of catalysts having different activities can be used and charged in the order of different activities, or a part of the catalyst can be inactivated. It may be diluted with a carrier or the like.

In addition, the reaction conditions in the present invention are not particularly limited, and any conditions that are generally used for this type of reaction can be used. For example, the raw material gas is 1-15% by volume, preferably 4-12% by volume propane and / or acrolein, 0.5-25% by volume, preferably 2-20% by volume molecular oxygen, 0-30% by volume. Preferably, a mixed gas consisting of 0 to 25% by volume of water vapor and the balance of an inert gas such as nitrogen is 300 to 8,000 h ⁻¹ under a pressure of 0.1 to 1.0 MPa in a temperature range of 200 to 400 ° C. What is necessary is just to contact an oxidation catalyst with the space velocity of (STP).
As the reaction gas, not only a mixed gas composed of propane and / or acrolein, molecular oxygen and an inert gas, but also an acrolein-containing mixed gas obtained by a dehydration reaction of glycerin or an oxidation reaction of propylene can be used. . In addition, air or oxygen can be added to the mixed gas as necessary.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. Hereinafter, for convenience, “parts by mass” may be referred to as “parts”. The acrolein conversion, acrylic acid selectivity and acrylic acid yield in the examples and comparative examples were determined by the following formulas.
Acrolein conversion (mol%)
= (Mole number of reacted acrolein) / (Mole number of supplied acrolein) × 100
Acrylic acid selectivity (mol%)
= (Number of moles of acrylic acid produced) / (number of moles of reacted acrolein) × 100
Acrylic acid yield (mol%)
= (Number of moles of acrylic acid produced) / (number of moles of acrolein supplied) × 100
<Example 1>
[Catalyst preparation]
While heating and stirring 1000 parts of pure water, 100 parts of ammonium paramolybdate, 24.3 parts of ammonium metavanadate, and 19.1 parts of ammonium paratungstate were dissolved therein. Separately, 20.5 parts of copper nitrate was dissolved while heating and stirring 100 parts of pure water. The obtained two solutions were mixed, and 5.5 parts of antimony trioxide and 7.2 parts of aluminum oxide were further added to obtain a starting material mixture. After this starting material mixture was spray-dried, the resulting dried product was sieved to 250 μm or less to obtain catalyst precursor powder. 300 parts of an α-alumina spherical carrier having an average particle diameter of 4 mm is put into a centrifugal fluid coating apparatus, and then 6.7 parts of a glycine aqueous solution having a concentration of 5% by mass is impregnated on the carrier, and then the catalyst precursor powder is supported on the carrier. And dried with hot air at about 90 ° C. to obtain a supported product. The obtained supported product was put in a crucible, heated at 2 ° C./min from room temperature in a box-type calcination furnace in which the oxygen concentration was adjusted to 10% by volume, and calcined at 400 ° C. for 6 hours to obtain Catalyst 1.
The supported rate of the catalyst 1 was 30% by mass, and the metal element composition excluding oxygen was as follows.
Catalyst _{composition: Mo 12 V 4.4 Sb 0.8 W} 1.5 Cu 1.8 Al 3.0
The loading rate was determined by the following formula.
Support rate (mass%) = (mass of supported catalyst powder (g)) / (mass of used carrier (g)) × 100
[Oxidation reaction]
A SUS U-shaped reaction tube with a total length of 300 mm and an inner diameter of 18 mm is filled with catalyst 1 so that the layer length is 100 mm, and a mixed gas of 2% by volume of acrolein, 3% by volume of oxygen, 10% by volume of water vapor, and 85% by volume of nitrogen. Was introduced at a space velocity of 5000 hr ⁻¹ (STP) to carry out acrolein oxidation reaction. The reaction temperature was adjusted so that the conversion rate of acrolein was about 93.5%. The reaction results are shown in Table 1.

<Example 2>
A catalyst 2 was obtained in the same manner as in Example 1 except that 7.1 parts of a 10% by mass glycine aqueous solution was used instead of 6.7 parts of a 5% by mass glycine aqueous solution in Example 1. . The supporting rate of the catalyst 2 and the metal element composition of the catalytically active component excluding oxygen were the same as those of the catalyst 1. Using catalyst 2, the acrolein oxidation reaction was carried out in the same manner as in Example 1. The results are shown in Table 1.

<Example 3>
In Example 1, a catalyst 3 was obtained in the same manner as in Example 1 except that 8 parts of a 20 mass% glycine aqueous solution was used instead of 6.7 parts of a 5 mass% glycine aqueous solution. The supporting rate of the catalyst 3 and the metal element composition of the catalytically active component excluding oxygen were the same as those of the catalyst 1. Using catalyst 3, an acrolein oxidation reaction was performed in the same manner as in Example 1. The results are shown in Table 1.

<Example 4>
A catalyst 4 was obtained in the same manner as in Example 1 except that 6.7 parts of an alanine aqueous solution having a concentration of 5% by mass was used instead of 6.7 parts of an aqueous glycine solution having a concentration of 5% by mass in Example 1. . The supporting rate of the catalyst 4 and the metal element composition of the catalytically active component excluding oxygen were the same as those of the catalyst 1. Using catalyst 4, the acrolein oxidation reaction was performed in the same manner as in Example 1. The results are shown in Table 1.

<Example 5>
In Example 1, catalyst 5 was obtained in the same manner as in Example 1 except that 7.1 parts of an alanine aqueous solution having a concentration of 10% by mass was used instead of 6.7 parts of an aqueous glycine solution having a concentration of 5% by mass. . The supporting rate of the catalyst 5 and the metal element composition of the catalytically active component excluding oxygen were the same as those of the catalyst 1. Using catalyst 5, the acrolein oxidation reaction was carried out in the same manner as in Example 1. The results are shown in Table 1.

<Example 6>
A catalyst 6 was prepared in the same manner as in Example 1 except that 8 parts of a threonine aqueous solution having a concentration of 20% by mass was used instead of 6.7 parts of an aqueous glycine solution having a concentration of 5% by mass in Example 1. The supporting rate of the catalyst 6 and the metal element composition of the catalytically active component excluding oxygen were the same as those of the catalyst 1. Using catalyst 6, the acrolein oxidation reaction was carried out in the same manner as in Example 1. The results are shown in Table 1.

<Comparative Example 1>
In Example 1, catalyst 7 was prepared in the same manner as in Example 1 except that 7.5 parts of water was used instead of 6.7 parts of an aqueous glycine solution having a concentration of 5% by mass. The supporting rate of the catalyst 7 and the metal element composition of the catalytically active component excluding oxygen were the same as those of the catalyst 1. Using catalyst 7, an acrolein oxidation reaction was carried out in the same manner as in Example 1. The results are shown in Table 1.

<Comparative example 2>
A catalyst 8 was prepared in the same manner as in Example 1 except that 7.5 parts of a 0.5% by mass lactic acid aqueous solution was used instead of 6.7 parts of a 5% by mass glycine aqueous solution in Example 1. Obtained. The supporting rate of the catalyst 8 and the metal element composition of the catalytically active component excluding oxygen were the same as those of the catalyst 1. Using catalyst 8, the acrolein oxidation reaction was performed in the same manner as in Example 1. The results are shown in Table 1.

<Comparative Example 3>
A catalyst 9 was obtained in the same manner as in Example 1 except that 7.5 parts of a lactic acid aqueous solution having a concentration of 25% by mass was used instead of 6.7 parts of a glycine aqueous solution having a concentration of 5% by mass in Example 1. . The supporting rate of the catalyst 9 and the metal element composition of the catalytically active component excluding oxygen were the same as those of the catalyst 1. Using catalyst 9, the acrolein oxidation reaction was performed in the same manner as in Example 1. The results are shown in Table 1.

<Example 7>
The catalyst prepared in Example 2 was packed so as to have a layer length of 2200 mm using a reactor composed of a SUS reaction tube having a total length of 3200 mm and an inner diameter of 25 mm and a shell for flowing a heat medium covering the SUS reaction tube. Acrolein oxidation reaction was performed by introducing a mixed gas of 7% by volume of acrolein, 8% by volume of oxygen, 15% by volume of water vapor, and 74% by volume of nitrogen into the reaction tube filled with the catalyst at a space velocity of 2500 hr ⁻¹ (STP). The reaction was continued for 4000 hours while changing the reaction temperature so that the acrolein conversion was almost constant. The results are shown in Table 2.

<Comparative example 4>
The catalyst prepared in Comparative Example 1 was subjected to an acrolein oxidation reaction in the same manner as in Example 7. The results are shown in Table 2.

Claims (4)

  A process for producing a catalyst for producing acrylic acid by catalytic gas phase oxidation of propane and / or acrolein containing molybdenum and vanadium as essential components in the presence of molecular oxygen or a molecular oxygen-containing gas, A process for producing a catalyst for producing acrylic acid, characterized in that   The method for producing a catalyst according to claim 1, comprising a raw material mixture preparation step, a raw material mixture drying step and a molding step, and adding an amino acid in at least one of these steps.   The method according to claim 1 or 2, wherein the amino acid has 2 to 4 carbon atoms. The manufacturing method of acrylic acid using the catalyst for acrylic acid manufacturing obtained by the manufacturing method in any one of Claims 1-3 .