KR101462633B1 - PROCESS FOR PREPARING Mo-Bi BASED MULTI-METAL OXIDE CATALYST - Google Patents

Abstract

The present invention relates to a composite metal oxide for the production of (meth) acrylic acid and acrolein, and more particularly to a molybdenum compound; Bismuth-based compounds; A salt of a metal selected from the group consisting of Fe, Zn, Cr, Mn, Cu, Ru, Pd, Ag, and Ru; A salt of a metal selected from the group consisting of Co, Cd, Ta, Pt, and Ni; Preparing a catalyst suspension by dissolving a salt of a metal selected from the group consisting of Na, K, Li, Rb, Cs, Ca, Mg, Sr, and Ba in water to introduce an organic alkali into the catalyst suspension; To adjust the pH of the catalyst suspension to 0.1 to 3.3, and drying the catalyst suspension. The present invention also relates to a method for producing a Mo-Bi based mixed metal oxide.
The Mo-Bi based composite metal oxide catalyst prepared according to the present invention can produce (meth) acrylic acid and acrolein with high yield by introducing an effective catalyst activity control technique.

Description

TECHNICAL FIELD [0001] The present invention relates to a Mo-Bi-based composite metal oxide,

The present invention relates to a method for producing a Mo-Bi based composite metal oxide, and more particularly, to a method for producing a Mo-Bi based composite metal oxide by applying an effective catalytic activity control method to produce (meth) acrylic acid and acrolein from propylene, Mo-Bi based composite metal oxide.

The process of preparing unsaturated fatty acids from olefins via unsaturated aldehydes is a typical catalytic vapor phase oxidation. In the partial oxidation reaction of olefins, molybdenum and bismuth-containing complex oxides, molybdenum and vanadium-containing complex oxides, or mixtures thereof are used as catalysts. (Meth) acrylic acid by oxidizing ethylene, propylene or isobutylene through (meth) acrolein, or by oxidizing naphthalene or arylene ether to produce phthalic anhydride or partially oxidizing benzene, butylene or butadiene to produce maleic anhydride .

Generally, the final product, (meth) acrylic acid is obtained by two-step catalytic gas phase partial oxidation reaction from propylene, propane, isobutylene, t-butyl alcohol or methyl-t-butyl ether . That is, in the first step, propylene or the like is oxidized by oxygen, a diluted inert gas, water vapor and an optional amount of catalyst to produce (meth) acrolein mainly, and in the second step oxygen, diluted inert gas, (Meth) acrolein is oxidized to produce (meth) acrylic acid. The first stage catalyst is a multi-component metal oxide based on Mo-Bi, which oxidizes propylene and the like to mainly produce (meth) acrolein. In addition, some (meth) acrolein is continuously oxidized on this catalyst, and part of (meth) acrylic acid is produced. The second stage catalyst is a multi-component metal oxide based on Mo-V, which mainly oxidizes (meth) acrolein in the (meth) acrolein-containing mixed gas produced in the first stage to mainly produce (meth) acrylic acid.

The reactor for carrying out such a process may be provided so as to be able to carry out both of the above-described two-step process in one apparatus or may be provided so as to be able to execute the two-step process in another apparatus.

As mentioned above, in most fixed bed gas phase catalytic reactions, the reactant concentration is a reaction in which the concentration of the reactant is reduced from the inlet to the outlet of the reactor and the product is increased. The characteristic of the fixed bed vapor phase catalytic reaction is that a hot spot is generated at the front end of the catalyst layer having a high concentration of reactants, and the temperature is high at this site and many byproducts other than the desired product are generated. Such by-products cause catalyst deactivation, which leads to catalytic component sublimation and sintering, thus shortening catalyst life. In order to solve this problem, a number of catalysts prepared by differentiating the kinds or composition ratios of the D (alkali) components in the catalyst composition formula so as to increase the activity from the inlet side to the outlet side and a plurality of catalysts having different occupancy spaces And a technique of filling a plurality of reaction zones so that the occupied space becomes smaller toward the exit direction. It is also possible to prepare several catalysts which are different from each other in terms of (a) occupying volume, (b) calcining temperature and / or (c) alkali metal element and / or amount, A method in which the catalytic activity is increased from the starting gas inlet direction to the outlet direction by providing the reaction zone provided by separating the catalyst layer of the catalyst bed into two or more layers in the axial direction of the tube.

As described above, a multi-component metal oxide catalyst (1-step catalyst) for producing acrolein acrylic acid in propylene based on Mo-Bi, and a multi-component metal oxide catalyst for producing acrylic acid in acrolein based on Mo- ) Is a technique for adjusting the activity of an alkali metal by controlling the type and / or amount of alkali metal and controlling the catalytic firing temperature, a technique for controlling the activity by changing the occupied area of the catalyst, and a technique of mixing the catalyst with an inert material Is known. In the commercialization process, the control of the catalytic activity by controlling the kind and amount of alkali metal is not uniformly distributed because a small amount of alkali metal is used, so much effort is required to control the catalytic activity. In addition, the method of controlling the activity by controlling the calcination temperature of the catalyst also has a limitation in controlling the catalytic activity reproducibly due to the uneven temperature variation inside the calcining furnace.

The present invention provides a method for producing a Mo-Bi based composite metal oxide having excellent selectivity by a catalyst activity control method which is more effective and excellent in reproducibility so that (meth) acrylic acid and acrolein can be produced from propylene etc. in high yield do.

The present invention relates to a process for producing an Mo-Bi based composite metal oxide represented by the following general formula (1), wherein the molybdenum compound; Bismuth-based compounds; A salt of a metal selected from the group consisting of Fe, Zn, Cr, Mn, Cu, Pd, Ag, and Ru; A salt of a metal selected from the group consisting of Co, Cd, Ta, Pt, and Ni; Preparing a catalyst suspension by dissolving a salt of a metal selected from the group consisting of Na, K, Li, Rb, Cs, Ca, Mg, Sr, and Ba in water to introduce an organic alkali into the catalyst suspension; To adjust the pH of the catalyst suspension to 0.1 to 3.3, and drying the catalyst suspension. The present invention also provides a method for producing the Mo-Bi based mixed metal oxide.

[Chemical Formula 1]

Mo _a Bi _b M ¹ _c M ² _d M ³ _e M ⁴ _f M ⁵ _g M ⁶ _h O _i

In this formula,

Mo is molybdenum,

Bi is bismuth,

M ¹ is at least one element selected from the group consisting of W, Sb, As, P, Sn and Pb,

M ² is at least one element selected from the group consisting of Fe, Zn, Cr, Mn, Cu, Pd, Ag and Ru,

M ³ is at least one element selected from the group consisting of Co, Cd, Ta, Pt and Ni,

M ⁴ is at least one element selected from the group consisting of Al, Zr, V and Ce,

M ⁵ is at least one element selected from the group consisting of Se, Ga, Ti, Ge, Rh and Au,

M ⁶ is at least one element selected from the group consisting of Na, K, Li, Rb, Cs, Ca, Mg, Sr,

a, b, c, d, e, f, g, h and i represent atomic ratios of the respective elements,

When a is 12, b is 0.01 to 20, c is 0 to 20, d is 0.001 to 15, e is 0.001 to 20, f is 0 to 20, g is 0 to 10, h is 0.001 to 10, It is a value determined according to the oxidation state of each component.

The present invention also provides a Mo-Bi based composite metal oxide, which is produced according to the above production method and represented by the above formula (1).

The present invention also provides a process for producing (meth) acrylic acid from at least one reactant selected from the group consisting of propylene, propane, isobutylene, t-butyl alcohol and methyl-t-butyl ether, (Meth) acrylic acid and (meth) acrolein using the composite metal oxide as a catalyst.

Hereinafter, a method for producing a Mo-Bi based composite metal oxide according to a specific embodiment of the present invention, a Mo-Bi based composite metal oxide produced thereby and a method for producing (meth) acrylic acid using the same as a catalyst will be described in detail . It is to be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

&Quot; Including "or" containing ", unless the context clearly dictates otherwise throughout the specification, refers to any element (or component) including without limitation, excluding the addition of another component .

According to one embodiment of the present invention, there is provided a method for producing an Mo-Bi based composite metal oxide represented by the following general formula (1), wherein the molybdenum compound; Bismuth-based compounds; A salt of a metal selected from the group consisting of Fe, Zn, Cr, Mn, Cu, Pd, Ag, and Ru; A salt of a metal selected from the group consisting of Co, Cd, Ta, Pt, and Ni; Preparing a catalyst suspension by dissolving a salt of a metal selected from the group consisting of Na, K, Li, Rb, Cs, Ca, Mg, Sr, and Ba in water to introduce an organic alkali into the catalyst suspension; , Adjusting the pH of the catalyst suspension to 0.1 to 3.3, and drying the catalyst suspension.

[Chemical Formula 1]

Mo _a Bi _b M ¹ _c M ² _d M ³ _e M ⁴ _f M ⁵ _g M ⁶ _h O _i

Wherein Mo is molybdenum; Bi is bismuth; M ¹ is at least one element selected from the group consisting of W, Sb, As, P, Sn and Pb; M ² is at least one element selected from the group consisting of Fe, Zn, Cr, Mn, Cu, Pd, Ag and Ru; M ³ is at least one element selected from the group consisting of Co, Cd, Ta, Pt and Ni; M ⁴ is at least one element selected from the group consisting of Al, Zr, V and Ce; M ⁵ is at least one element selected from the group consisting of Se, Ga, Ti, Ge, Rh and Au; M ⁶ is at least one element selected from the group consisting of Na, K, Li, Rb, Cs, Ca, Mg, Sr, and Ba; a, b, c, d, e, f, g, h, and i represent atomic ratios of the respective elements; when a = 12, b is 0.01 to 20, c is 0 to 20, d is 0 to 15, e is 0 to 20, f is 0 to 20, g is 0 to 10, h is 0 to 10, B is 0.01 to 15, c is 0 to 10, d is 0.001 to 10, e is 0.001 to 10, f is 0 to 10, 15, g is 0 to 10, h is 0.001 to 10, and i is a value determined according to the oxidation state of each component.

The present inventors have found that, by controlling the activity of a Mo-Bi based composite metal oxide catalyst used in the production of (meth) acrylic acid and (meth) acrolein from propylene or the like, (Meth) acrylic acid and (meth) acrolein can be prepared at a high yield by controlling the activity. Thus, the present invention has been completed.

In particular, the present invention is not a technique for achieving the control of activity while changing the content of alkali metal or the type of alkali metal by a new method for controlling the activity of Mo-Bi based metal oxide catalyst as the first reaction catalyst, The pH of the catalyst suspension in which the salt of the metal component contained in the catalyst is dissolved in water is adjusted to 0.1 to 3.3 and then the catalyst suspension is dried to produce the Mo-Bi based composite metal oxide. Thus, . According to the present invention, as described above, a catalyst having a uniform catalyst composition, easy control of activity, and excellent reproducibility can be manufactured by using the method of adjusting pH to the optimum range.

First, the method for producing a Mo-Bi based composite metal oxide of the present invention includes a step of dissolving or dispersing a salt of a metal component contained in the composite metal oxide together with a molybdenum compound and a bismuth compound in water to prepare a catalyst suspension do.

At least one selected from the group consisting of Fe, Zn, Cr, Mn, Cu, Pd, Ag and Ru may be used as the metal component, and at least one selected from the group consisting of Co, Cd, Ta, At least one species selected from the group consisting of Na, K, Li, Rb, Cs, Ca, Mg, Sr, and Ba can be used.

The catalyst suspension may be a salt of a metal selected from the group consisting of W, Sb, As, P, Sn, Pb, Al, Zr, V, Ce, Se, Ga, Ti, Ge, Rh, May be further included.

The molybdenum-based compound, the bismuth-based compound, and the salt of the metal component are not particularly limited, and may be any compound capable of dissolving in water including each metal component. For example, as a starting material, a compound which can be converted to an oxide by heating (i.e., calcining) in the presence of an oxide or at least oxygen, such as a halide, nitride, formate, oxalate, citrate, acetate, carbonate , An amine complex, an ammonium salt, or a hydroxide can be used. At this time, the molybdenum compound, the bismuth compound, and the salt of the metal component may be used in an amount determined according to the stoichiometry based on the composition of each component contained in the final Mo-Bi based composite metal oxide.

After the catalyst suspension is prepared as described above, the method for preparing the Mo-Bi based composite metal oxide of the present invention includes the step of adding the organic alkali to the catalyst suspension to adjust the pH of the catalyst suspension to 0.1 to 3.3 .

The pH of the catalyst suspension can be adjusted to the optimum range depending on the use of the final catalyst using an organic alkali, that is, a basic solution such as pyridine or ammonia. Here, the organic alkali may be an amine compound containing an alkyl group or an aryl group having 1 to 12 carbon atoms, for example, pyridine, ammonia, methylamine, ethylamine, and the like.

The pH of the catalyst suspension adjusted by adding the basic solution as described above may be in the range of 0.1 to 3.3, preferably 0.3 to 3.1, more preferably 0.5 to 3.0. The Mo-Bi based composite metal oxide is produced by maintaining the pH of the catalyst suspension in which the salt of the metal component contained in the final catalyst is dissolved in water within the above-described range to thereby stably produce a catalyst of excellent quality and a uniform quality have.

In particular, the pH of the catalyst suspension can be adjusted according to the specific catalyst application of the Mo-Bi based composite metal oxide to be finally produced. That is, when the Mo-Bi based composite metal oxide is used as a catalyst in the first step reaction in which (meth) acrolein and / or (meth) acrylic acid is produced from propylene or the like, The catalyst packed on the inlet side is referred to as a front catalyst and the catalyst packed on the outlet side of the reaction gas is referred to as a rear catalyst. At this time, the pH of the catalyst suspension may be regulated by varying the catalyst activity depending on the use of the Mo-Bi based composite metal oxide as a front catalyst or a rear catalyst.

For example, when the Mo-Bi based composite metal oxide is used as a front catalyst in the first step reaction, sintering, fouling, and recrystallization due to a rapid exothermic reaction, it is desirable to maintain the activity lower than that of the rear catalyst so as to prevent the catalyst from being damaged or channeling in the reactor due to occurrence of phenomena such as sublimation of active phase. Thus, in order to achieve an optimum activity range as a front catalyst in the first-step reaction in which (meth) acrolein and / or (meth) acrylic acid is produced, the pH of the catalyst suspension is preferably 1.0 or more Can be adjusted to a high level. That is, it is possible to increase the pH of the catalyst suspension to increase the catalyst activity control effect, and to control the prepared catalyst activity to a lower range to induce stable reaction. On the other hand, when the Mo-Bi based composite metal oxide is used as a rear catalyst in the first-step reaction, it is necessary to maintain the activity higher than that of the front catalyst so as to improve the conversion rate and yield of the entire process desirable.

At this time, the activity of the front catalyst may be 50% to 90%, preferably 55%, more preferably 85%, more preferably 60% to 80% of the activity of the rear catalyst have.

After the pH of the catalyst suspension is adjusted to the optimum range in this way, the method for producing the Mo-Bi based composite metal oxide of the present invention includes a step of drying the catalyst suspension. The drying step can be firstly dried as a solid after evaporating the system containing the catalyst suspension.

Meanwhile, the Mo-Bi based composite metal oxide prepared according to the present invention can be used alone by drying the catalyst itself as described above, or supported on an inert carrier as described above. When the inert carrier is used together, the pH-adjusted catalyst suspension may be further contacted with an inert carrier to carry the catalyst before carrying out the drying step. For example, the catalyst suspension may be supported on a carrier by a conventional method such as vacuum, nozzle spraying or the like. The carrier may be porous or nonporous alumina, silica-alumina, silicon carbide, titanium dioxide, magnesium oxide, aluminum sponge, and the like. In addition, the carrier may be a sylinder type, a hallow cylindrical shape, or a sphere, but the shape is not particularly limited. For example, it is preferable that the ratio of the length of the cylindrical catalyst to the diameter (outer diameter) (L / D) is in the range of 1 to 1.3, more preferably L / D = 1. In the case of cylindrical or spherical shape, the outer diameter of the catalyst is preferably 3 to 10 mm, more preferably 5 to 8 mm.

Further, the dried composite metal oxide may be further subjected to a step of forming into a powder, a tablet, and a granule through a pulverizing process or the like. In this case, it is possible to add inorganic fibers such as glass fibers and various types of whiskers widely known for improving the strength and frictional resistance of the catalyst. In order to control the properties of the catalyst so as to have excellent reproducibility, additives well known as powdery binders such as ammonium nitrate, cellulose, starch, polyvinyl alcohol, and stearic acid can be used.

The method for producing a Mo-Bi based composite metal oxide according to the present invention may further comprise a step of calcining the formed product or the product supported on the support at 300 to 600 ° C for about 1 to 10 hours or more under an air flow of 0.2 to 2 m / . The firing is an inert gas or an oxidizing atmosphere (e.g., air or a mixed gas atmosphere of an inert gas and oxygen), the other a reducing atmosphere (e.g., inert gas, oxygen, and NH _3, CO and / or a mixture of H ₂ gas Atmosphere). In addition, the firing time can be several minutes to several hours, and can generally be shortened as the temperature increases.

According to another embodiment of the present invention, a Mo-Bi based composite metal oxide may be prepared by the above-described method. In particular, the Mo-Bi based composite metal oxide may be represented by the following formula (1).

[Chemical Formula 1]

Mo _a Bi _b M ¹ _c M ² _d M ³ _e M ⁴ _f M ⁵ _g M ⁶ _h O _i

Wherein Mo is molybdenum; Bi is bismuth; M ¹ is at least one element selected from the group consisting of W, Sb, As, P, Sn and Pb; M ² is at least one element selected from the group consisting of Fe, Zn, Cr, Mn, Cu, Pd, Ag and Ru; M ³ is at least one element selected from the group consisting of Co, Cd, Ta, Pt and Ni; M ⁴ is at least one element selected from the group consisting of Al, Zr, V and Ce; M ⁵ is at least one element selected from the group consisting of Se, Ga, Ti, Ge, Rh and Au; M ⁶ is at least one element selected from the group consisting of Na, K, Li, Rb, Cs, Ca, Mg, Sr, and Ba; a, b, c, d, e, f, g, h, and i represent atomic ratios of the respective elements; When a is 12, b is 0.01 to 20, c is 0 to 20, d is 0.001 to 15, e is 0.001 to 20, f is 0 to 20, g is 0 to 10, h is 0.001 to 10, B is 0.01 to 15, c is 0 to 10, d is 0.001 to 10, e is 0.001 to 10, f is 0 to 10, 15, g is 0 to 10, h is 0.001 to 10, and i is a value determined according to the oxidation state of each component.

The Mo-Bi based composite metal oxide of the present invention can be used as a catalyst, and in particular, can be used as a catalyst for the catalytic gas phase partial oxidation reaction.

According to still another embodiment of the present invention, there is provided a process for producing a polyimide precursor solution, which comprises reacting propylene, propane, isobutylene, t-butyl alcohol or methyl-t-butyl ether (Meth) acrylic acid and acrolein from at least one kind of reactant selected from the group consisting of (meth) acrylic acid and acrolein.

In the method of producing (meth) acrylic acid and acrolein of the present invention, when the Mo-Bi based composite metal oxide catalyst is loaded in the reactor, the catalyst on the side of the reaction gas inlet in the reactor, that is, the front catalyst, It can be packed so that it is manufactured using the catalyst of the negative side, that is, the catalyst suspension of high pH condition as compared with the rear catalyst.

The process conditions for the reaction for producing (meth) acrylic acid may be those generally used for producing (meth) acrylic acid and (meth) acrolein from reactants such as propylene by vapor phase catalytic oxidation. For example, the starting gas may be a gas having a propylene space velocity of 100 hr ^-1 , an inert gas acting as molecular oxygen and a diluent (for example, nitrogen, carbon dioxide, steam, etc.) Temperature, a pressure in the range of 0.1 to 3 kg / cm ² G, and the like, the desired reaction can be carried out by contacting with the Mo-Bi based composite metal oxide catalyst.

The Mo-Bi based composite metal oxide catalyst is preferably 20% or more, more preferably 20% or more, and more preferably 25% or less, more preferably 20% or more of the total filling height when filled with the catalyst on the reaction gas inlet side in the reactor, Or 25% to 50%, more preferably 30% or 30% to 50%. The shear catalyst of the Mo-Bi based composite metal oxide may be filled in the range of 20% to 50% of the entire filling height in terms of controlling the activity.

The process for producing (meth) acrylic acid and acrolein according to the present invention is characterized in that the yield of (meth) acrolein and (meth) acrylic acid is 89% by effectively controlling the catalytic activity by filling the Mo- Or more, preferably 90% or more, and acrylic acid and acrolein can be produced at a high yield.

In the present invention, matters other than those described above can be added or subtracted as needed, and therefore, the present invention is not particularly limited thereto.

The present invention relates to a method for producing an Mo-Bi based composite metal oxide which exhibits an activity suitable for the detailed use of a catalyst according to a filling position in a reactor by adjusting the pH of the catalyst suspension to an optimal range by introducing an effective catalyst activity control technique, (Meth) acrylic acid and acrolein using the Mo-Bi based composite metal oxide.

Particularly, the Mo-Bi based composite metal oxide prepared according to the present invention can be produced by reacting a hot spot region in the first step in the production of (meth) acrolein or (meth) acrylic acid from propylene or isobutylene (Meth) acrylic acid and acrolein can be produced at a high yield, and high-load operation can be performed, so that excellent performance can be exhibited. Further, the pH of the catalyst suspension can be controlled more easily than the activity of the alkali metal only, so that the catalytic activity can be easily controlled according to the purpose.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the scope of the present invention is not limited to the following examples.

Example  One

(1) was prepared by dissolving 1,000 g of ammonium molybdate while stirring and heating 2,500 mL of distilled water at 70 to 85 ° C. 274 g of bismuth nitrate, 228 g of iron nitrate and 4.7 g of potassium nitrate were added to 400 mL of distilled water, and the mixture was mixed well. Then, 71 g of nitric acid was added and dissolved to prepare a solution (2). Solution (3) was prepared by dissolving 686 g of cobalt nitrate in 200 mL of distilled water. After mixing the solutions (2) and (3), the solution was mixed with the solution (1) while maintaining the temperature of the solution at 40 to 60 ° C to prepare a catalyst suspension.

The pH of the suspension was adjusted to 0.50 using a 5% solution of ammonia water in the catalyst suspension.

The pH-adjusted suspension was dried and the resulting catalyst solid was ground to below 150 μm. The pulverized catalyst powder was mixed for 2 hours and then molded into a cylindrical shape. At this time, the catalyst outer diameter was molded to a size of 4.0 to 8.0 mm, and the resultant was calcined at 480 DEG C for 5 hours in an air atmosphere to prepare a final Mo-Bi based composite metal oxide catalyst (Catalyst A). At this time, the composition ratio of the catalyst element excluding oxygen is Mo ₁₂ Bi _{1 .2} Fe _{1 .2} Co ₅ K _{0 . 1} ASD operation.

Example  2

A final Mo-Bi based composite metal oxide catalyst (catalyst B) was prepared in the same manner as in Example 1, except that the pH of the suspension was adjusted to 1.0 using a 5% solution of ammonia water in the prepared catalyst suspension.

Example  3

The final Mo-Bi based composite metal oxide catalyst (Catalyst C) was prepared in the same manner as in Example 1, except that the pH of the suspension was adjusted to 1.5 using a 5% solution of ammonia water in the prepared catalyst suspension.

Example  4

A final Mo-Bi based composite metal oxide catalyst (catalyst D) was prepared in the same manner as in Example 1, except that the pH of the suspension was adjusted to 2.0 using a 5% solution of ammonia water in the prepared catalyst suspension.

Example  5

A final Mo-Bi based composite metal oxide catalyst (catalyst E) was prepared in the same manner as in Example 1, except that the pH of the suspension was adjusted to 2.5 using a 5% solution of ammonia water in the prepared catalyst suspension.

Example  6

A final Mo-Bi based composite metal oxide catalyst (Catalyst F) was prepared in the same manner as in Example 1, except that the pH of the suspension was adjusted to 3.0 using a 5% solution of ammonia water in the prepared catalyst suspension.

Comparative Example  One

The final Mo-Bi based composite metal oxide catalyst (Catalyst G) was prepared in the same manner as in Example 1, except that the prepared catalyst suspension was subjected to a drying step without pH adjustment step (pH = 0.05).

Comparative Example  2

Except for the preparation of the Mo-Bi based composite metal oxide represented by the following formula (3) by applying 7 g of potassium nitrate to the prepared catalyst suspension by adjusting the amount of alkali metal without adjusting the pH (pH = 0.05) , A final Mo-Bi based composite metal oxide catalyst (Catalyst H) was prepared in the same manner as in Comparative Example 1. At this time, the composition ratio of the catalyst element excluding oxygen is Mo ₁₂ Bi _{1 .2} Fe _{1 .2} Co ₅ K _{0 . 15} .

Comparative Example  3

Except for the preparation of the Mo-Bi based composite metal oxide represented by the following formula (4) by applying 8.1 g of potassium nitrate as a method of controlling the amount of alkali metal in the prepared catalyst suspension without any pH adjustment step (pH = 0.05) , A final Mo-Bi based composite metal oxide catalyst (Catalyst I) was prepared in the same manner as in Comparative Example 1. At this time, the composition ratio of the catalyst element excluding oxygen is Mo ₁₂ Bi _{1 .2} Fe _{1 .2} Co ₅ K _{0 . 17} .

Comparative Example  4

Except for the preparation of the Mo-Bi based composite metal oxide represented by the following Chemical Formula 5 by applying 9.5 g of potassium nitrate as a method of controlling the amount of alkali metal in the prepared catalyst suspension without any pH adjustment step (pH = 0.05) , A final Mo-Bi based composite metal oxide catalyst (Catalyst J) was prepared in the same manner as in Comparative Example 1. At this time, the composition ratio of the catalyst element excluding oxygen is Mo ₁₂ Bi _{1 .2} Fe _{1 .2} Co ₅ K _{0 . 20} .

Comparative Example  5

The Mo-Bi based mixed metal oxide catalyst was prepared in the same manner as in Example 1 except that the pH of the suspension was adjusted to 3.5 using ammonia water 5% solution in the prepared catalyst suspension, And the molding itself was impossible.

Experimental Example  One

In a stainless steel reaction tube having an inner diameter of 1 inch and a length of 80 cm heated by molten nitrate, 5 cm of inert material alumina silica was charged in the direction of the outlet from the reaction gas inlet, (Catalysts A to J) prepared in accordance with Example 4 were filled.

As the reaction conditions, those generally used for producing (meth) acrylic acid and (meth) acrolein from reactants such as propylene by vapor catalytic oxidation can be adopted. For example, it is preferable that the starting gas contains 60 to 80% by volume of an inert gas acting as a diluent (for example, nitrogen, carbon dioxide, steam or the like) at 4 vol% or more, 10 to 20 vol% The gas mixture is contacted with the catalyst of the present invention at a temperature in the range of 250 to 500 ° C, at a pressure in the range of 0.1 to 3 kg / cm ² G and at a space velocity in the range of 300 to 5,000 hr ^-1 (STP) . Reaction products and products were analyzed by gas chromatograph analyzer.

For the first stage catalytic reaction as described above, the conversion of the reactant (propylene) and the yield were calculated according to the following equations (1), (2) and (3).

[Equation 1]

[Equation 2]

[Equation 3]

The results of the reaction tests on the Mo-Bi based composite metal oxide catalysts (catalysts A to J) prepared according to Examples 1 to 6 and Comparative Examples 1 to 4 are shown in Table 1 below.

division Suspension pH Alkali metal
Content (index h value) Propylene
Conversion Rate
(%, 300 DEG C) Acrylic acid +
Acrolein
Selectivity (mol%) Acrylic acid +
Acrolein
Yield (mol%) Example 1 (Catalyst A) 0.50 0.1 86.38 93.59 80.84 Example 2 (Catalyst B) 1.00 0.1 83.58 93.54 78.18 Example 3 (Catalyst C) 1.50 0.1 79.57 94.56 75.24 Example 4 (Catalyst D) 2.00 0.1 75.14 94.22 70.80 Example 5 (Catalyst E) 2.50 0.1 70.08 96.63 67.02 Example 6 (Catalyst F) 3.00 0.1 65.57 95.42 62.57 Comparative Example 1 (Catalyst G) 0.05 0.1 93.60 97.31 86.96 Comparative Example 2 (Catalyst H) 0.05 0.15 88.03 92.21 81.17 Comparative Example 3 (Catalyst I) 0.05 0.17 89.83 92.93 83.30 Comparative Example 4 (Catalyst J) 0.05 0.20 88.15 91.71 80.84

As shown in Table 1, the Mo-Bi based composite metal oxides of Examples 1 to 6 prepared by adjusting the pH of the catalyst suspension to the optimum range according to the present invention are easily controlled in activity depending on the pH change, . ≪ / RTI > In particular, it can be seen that as the pH of the suspension is increased from 0.50 to 3.0, the yield according to the catalytic activity of the Mo-Bi based composite metal oxide to be produced is adjusted to a consistent direction from 80.84% to 62.57%. Accordingly, it is an object of the present invention to provide a process for producing (meth) acrylic acid and acrolein in a high conversion ratio and an excellent yield, Bi-based composite metal oxide can be produced.

On the other hand, it can be seen that the composite metal oxides of Comparative Examples 1 to 4, which were produced only by varying the alkali metal content without adjusting the pH separately, can not provide consistent control over the catalytic activity. Particularly, when 5 g of potassium nitrate (h value 0.1) was used as the alkali metal in Comparative Example 1 and 7 g of potassium nitrate (h value 0.15) was used in Comparative Example 2, the yield according to the catalytic activity was 86.96% to 81.17 %. However, when 8.1 g of potassium nitrate (h value 0.17) was used in Comparative Example 3, the yield was further increased to 83.30% by catalytic activity, and when 9.5 g of potassium nitrate (h 0.20) was used in Comparative Example 4 And decreased to 80.84%. As a result, it can be seen that control of the catalytic activity of the Mo-Bi based composite metal oxide is impossible when the alkali metal content is different as in Comparative Examples 1 to 4.

Experimental Example  2

Manufacturing example  1 to 6 and comparison Manufacturing example  One

The Mo-Bi based composite metal oxide catalysts (catalysts A to G) prepared according to Examples 1 to 6 and Comparative Example 1 were used as front catalysts and rear catalysts as shown in Table 2 below (Meth) acrylic acid and (meth) acrolein were prepared.

At this time, the catalyst performance was verified through the catalyst filling (operation time 1,000 hours) and the activity test as follows.

First, 150 mm of an inert material alumina silica was filled in a 1-inch-diameter and 3-m-long stainless steel reaction tube heated with molten nitrate in the direction of the outlet from the reaction gas inlet, and then the reaction was carried out in the same manner as in Examples 1 to 6 and Comparative Example (Catalysts A to G) prepared in accordance with Example 1 were filled in 2,800 mm in the manner shown in Table 2 below.

Particularly, in Production Examples 1 to 6, catalysts A to F whose activity was controlled by adjusting pH to the optimum range according to Examples 1 to 6 were used as shear catalysts, A high activity catalyst (Catalyst G) without activity control, which was produced without control, was used as the catalyst for the rear end so that the front end catalyst and the rear end catalyst were arranged to increase the activity. However, in the case of Comparative Preparation Example 1, both the shear catalyst and the rear end catalyst were filled according to Comparative Example 1 with a high activity catalyst (Catalyst G) without activity control, which was prepared in the conventional manner without separate pH adjustment.

The results of the reaction tests of Production Examples 1 to 6 and Comparative Production Examples using the Mo-Bi based composite metal oxide catalysts (Catalysts A to G) prepared according to Examples 1 to 6 and Comparative Example 1 are shown in Table 2 below .

division Shear catalyst Rear end catalyst Propylene conversion rate
(%, 300 DEG C) Acrylic acid + acrolein
Yield (mol%) ingredient Filling
Length
(mm) ^* Filling
ratio
(%) ingredient Filling
Length
(mm) ^* Filling
ratio
(%) Production Example 1 Catalyst A 800 28.60 Catalyst G 2,000 71.40 96.24 89.40 Production Example 2 Catalyst B 800 28.60 Catalyst G 2,000 71.40 96.13 93.10 Production Example 3 Catalyst C 800 28.60 Catalyst G 2,000 71.40 95.84 92.50 Production Example 4 Catalyst D 1,000 35.70 Catalyst G 1,800 64.30 94.32 93.78 Production Example 5 Catalyst E 1,200 42.85 Catalyst G 1,600 57.20 94.12 91.64 Production Example 6 Catalyst F 1,500 53.57 Catalyst G 1,300 46.43 94.87 89.13 Comparative Preparation Example 1 Catalyst G 800 28.60 Catalyst G 2,000 71.40 96.75 88.13 ^* L / OD = 1, L: catalyst length, OD: catalyst outer diameter

As shown in Table 2 above, the Mo-Bi based composite metal oxide catalysts (Catalysts A to F) of Examples 1 to 6, in which the pH of the catalyst suspension was adjusted to the optimum range to control the catalytic activity, As a result, it was found that the reaction yields of Preparation Examples 1 to 6, which were used as catalysts for the front catalysts, ranged from 89.13% to 93.78%. On the other hand, in the case of Comparative Preparation Example 1 in which both the shear catalyst and the rear end catalyst were filled with the Mo-Bi based composite metal oxide catalyst of Comparative Example 1 (catalyst G) without adjusting the pH in the conventional manner, And 88.13%, respectively.

Thus, according to the present invention, the pH of the catalyst suspension was adjusted to the optimum range to prepare the Mo-Bi based composite metal oxide catalysts (catalysts A to F) of Examples 1 to 6, Examples 1 to 6 show that the control of the activity of the first-stage catalyst suppresses the reaction at the hot spot region, and thus it is possible to produce acrylic acid having a high thermal stability and a high yield of the catalyst as well as a high-load operation.

Claims (11)

delete delete delete delete delete delete delete delete (Meth) acrylic acid and (meth) acrolein from at least one reaction product selected from the group consisting of propylene, propane, isobutylene, t-butyl alcohol and methyl-t-butyl ether, By using a Mo-Bi based composite metal oxide as a catalyst,
In order to fill the Mo-Bi based mixed metal oxide catalyst in the reactor, the catalyst on the side of the reaction gas inlet side in the reactor is filled in the slurry solution having a pH higher than that of the catalyst on the outlet side of the reaction gas. ) Process for producing acrylic acid and (meth) acrolein:
[Chemical Formula 1]
Mo _a Bi _b M ² _d M ³ _e M ⁶ _h O _i
In this formula,
Mo is molybdenum,
Bi is bismuth,
M ² is at least one element selected from the group consisting of Fe, Zn, Cr, Mn, Cu, Pd, Ag and Ru,
M ³ is at least one element selected from the group consisting of Co, Cd, Ta, Pt and Ni,
M ⁶ is at least one element selected from the group consisting of Na, K, Li, Rb, Cs, Ca, Mg, Sr,
a, b, d, e, h, and i represent atomic ratios of the respective elements,
When a = 12, b is 0.01 to 20, d is 0.001 to 15, e is 0.001 to 20, h is 0.001 to 10, and i is a value determined according to the oxidation state of each component. 10. The method of claim 9,
(Meth) acrylic acid and (meth) acrolein, wherein the activity of the catalyst on the reaction gas inlet side is 50% to 90% of the activity of the catalyst on the outlet side of the reaction gas. 10. The method of claim 9,
(Meth) acrylic acid and (meth) acrolein such that the Mo-Bi based composite metal oxide catalyst is filled at least 20% of the total filling height.