JP3792385B2 - Method for producing catalyst for synthesis of unsaturated carboxylic acid - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a catalyst used when synthesizing an unsaturated carboxylic acid by gas phase catalytic oxidation of an unsaturated aldehyde, a catalyst obtained by the production method, and producing an unsaturated carboxylic acid using the catalyst. On how to do.
[0002]
[Prior art]
Conventionally, as a method of using an organic substance in producing a catalyst used for producing an unsaturated carboxylic acid by gas-phase catalytic oxidation of an unsaturated aldehyde, JP-A-57-204230 and JP-A-60-239439 are disclosed. In the publication, a method for adding organic compounds such as alcohols and nitrogen-containing heterocyclic compounds during the preparation of the catalyst raw material slurry is proposed. In JP-A-57-204230 and JP-A-60-48143, etc., a method of adding alcohols during molding of the supported catalyst, and in JP-A-5-309273, alcohols are added during extrusion molding. A method has been proposed.
[0003]
However, the catalysts produced by these methods are not satisfactory in reaction results and are currently desired to be further improved industrially.
[0004]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to provide a method for producing a catalyst capable of synthesizing an unsaturated aldehyde in a high yield by gas phase catalytic oxidation of an unsaturated aldehyde.
[0005]
[Means for Solving the Problems]
The present invention relates to a method for producing a catalyst containing at least phosphorus, molybdenum, and vanadium, which is used when synthesizing an unsaturated carboxylic acid by vapor-phase catalytic oxidation of an unsaturated aldehyde, and includes a mixed solution containing a catalyst component or an aqueous solution In a method in which a dry powder obtained from a slurry is dry-molded and then heat-treated, the dry powder is at least 30 parts by weight of methyl alcohol with respect to 100 parts by weight of a dry solution of a mixed solution or an aqueous slurry containing a catalyst component. A method for producing an unsaturated carboxylic acid synthesis catalyst, comprising: mixing at least one organic compound selected from the group consisting of ethyl alcohol, propyl alcohol, butyl alcohol and acetone; .
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The method for producing a catalyst of the present invention can be applied to a catalyst containing at least phosphorus, molybdenum, and vanadium, which is used when a unsaturated aldehyde is synthesized by vapor-phase catalytic oxidation to synthesize unsaturated carboxylic acid. and catalytic oxidation is suitable for synthesis of methacrylic acid of the general formula _{P a Mo b V c Cu d} X e Y f Z g O h
(Wherein P, Mo, V, Cu and O represent phosphorus, molybdenum, vanadium, copper and oxygen, respectively, X represents antimony, bismuth, arsenic, germanium, zirconium, tellurium, silver, selenium, silicon, tungsten And at least one element selected from the group consisting of boron and Y, at least one element selected from the group consisting of iron, zinc, chromium, magnesium, tantalum, cobalt, manganese, barium, gallium, cerium and lanthanum Z represents at least one element selected from the group consisting of potassium, rubidium, cesium and thallium, a, b, c, d, e, f, g and h are atomic ratios of the respective elements Where b = 12, a = 0.5-3, c = 0.01-3, d = 0-2, e = 0-3, f = 0-3 A g = 0.01 to 3, h is preferably applied to a catalyst having a composition represented by the the atomic ratio of oxygen required to satisfy the valence of each component).
[0007]
In the present invention, the method for preparing the mixed solution or aqueous slurry containing the catalyst component is not particularly limited, and a well-known precipitation method, oxide mixing method, or the like may be used as long as the component is not significantly unevenly distributed. Can be used.
[0008]
As raw materials for the catalyst component, oxides, nitrates, carbonates, ammonium salts and the like of each element can be used in combination. For example, ammonium paramolybdate, molybdenum trioxide, etc. can be used as the molybdenum raw material, and ammonium metavanadate, vanadium pentoxide, etc. can be used as the vanadium raw material.
[0009]
In the present invention, the method for drying the mixed solution or aqueous slurry containing the catalyst component is not particularly limited, and for example, an evaporation drying method, a spray drying method, a drum drying method, an air flow drying method, or the like can be applied. The model of the dryer used for drying, the drying temperature, and the like are not particularly limited, and the model, drying conditions, and the like can be appropriately selected in order to obtain a desired dried product.
[0010]
The dried product thus obtained is mixed with at least one organic compound selected from the group consisting of methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol and acetone (hereinafter referred to as an organic compound such as alcohol).
[0011]
The amount of the organic compound such as alcohol to be mixed with the dried product is at least 30 parts by weight, preferably 35 to 100 parts by weight with respect to 100 parts by weight of the dried product. When the amount of the organic compound such as alcohol added to the dried product is less than 30 parts by weight, the effect of the addition is not sufficiently exhibited. On the other hand, when the addition amount exceeds 100 parts by weight, there are problems such as complicated mixing operation and post-treatment, although the addition effect itself is obtained.
[0012]
In the present invention, for mixing the dried product with an organic compound such as alcohol, a known mixing or kneading machine such as a double-arm kneader, a continuous biaxial pug mixer, or a high-speed stirring mixer can be used. . In mixing, in addition to organic compounds such as alcohol, a small amount of water or conventionally known organic or inorganic additives such as hydroxypropyl cellulose, carboxymethyl cellulose, polyvinyl alcohol, graphite, etc. may be added. .
[0013]
The method for drying the mixture of the dried product and an organic compound such as alcohol is not particularly limited, and examples thereof include a method using a conventionally known dryer such as a box-type hot air dryer, a band-type dryer, and a microwave dryer. .
[0014]
In the present invention, the dried product obtained by mixing an organic compound such as alcohol with a dried product is pulverized and classified as necessary to adjust the particle size. The pulverization method is not particularly limited, and examples thereof include methods using various conventionally known pulverizers such as a ball mill, a high-speed rotary mill, and a jet mill. Further, the classification method is not particularly limited, and examples thereof include methods using various conventionally known classifiers such as a mesh fixed screen, a vibration screen, and an in-plane motion screen.
[0015]
Subsequently, the dry powder thus obtained is dry-molded. A method for dry-molding the dry powder is not particularly limited, and examples of such a molding method include conventionally known compression molding methods such as a tableting molding method and a press molding method. The shape to be molded is not particularly limited, and examples thereof include conventionally known shapes such as a columnar shape and a ring shape. In the dry molding, conventionally known additives such as graphite and talc may be added.
[0016]
Finally, the dry-formed product is heat-treated to form a catalyst. The heat treatment method and heat treatment conditions are not particularly limited, and known treatment methods and conditions can be applied. Examples of the heat treatment method include a method of treating at 200 to 500 ° C., preferably 300 to 450 ° C. under an air flow and / or an inert gas flow.
[0017]
In this way, the mechanism by which the catalyst performance is improved by mixing a predetermined amount of an organic compound such as ethyl alcohol with the dried product, dry-molding the dried product, and then heat-treating is not clear at this stage. This is presumably because a more advantageous catalytically active structure is formed in the gas phase catalytic oxidation of a saturated aldehyde.
[0018]
As the reaction conditions for the reaction for synthesizing an unsaturated carboxylic acid from an unsaturated aldehyde using the catalyst obtained by the present invention, conventionally known normal conditions can be applied, but the concentration of the unsaturated aldehyde in the raw material gas is 1 to 20% by volume is suitable, and 3 to 10% by volume is particularly preferable. Further, the molar ratio of unsaturated aldehyde to molecular oxygen in the raw material gas is preferably 1: 0.3 to 4, particularly preferably 1: 0.4 to 3. Although it is economical to use air as the molecular oxygen source, air enriched with pure oxygen can also be used if necessary. The source gas may be diluted with an inert gas such as nitrogen, water vapor or carbon dioxide. The reaction pressure is preferably from normal pressure to several atmospheres. The reaction temperature can be selected in the range of 230 to 450 ° C, but 250 to 400 ° C is particularly preferable.
[0019]
【Example】
Hereinafter, the effects of the present invention will be shown by examples and comparative examples. In the examples and comparative examples, “parts” means parts by weight. The reaction product was analyzed by gas chromatography. The reaction rate of the unsaturated aldehyde, the selectivity of the unsaturated carboxylic acid produced and the single yield of the unsaturated carboxylic acid are defined as follows.
Reaction rate of unsaturated aldehyde (%) = B / A × 100
Selectivity of unsaturated carboxylic acid (%) = C / B × 100
Single yield of unsaturated carboxylic acid (%) = C / A × 100
Here, A represents the number of moles of unsaturated aldehyde supplied, B represents the number of moles of reacted unsaturated aldehyde, and C represents the number of moles of unsaturated carboxylic acid produced.
[0020]
[Example 1]
100 parts of molybdenum trioxide, 3.7 parts of vanadium pentoxide, and 8.7 parts of 85 wt% phosphoric acid were mixed with 800 parts of pure water. This was heated and stirred under reflux for 3 hours, then 1.4 parts of copper nitrate was added thereto, and the mixture was again heated and stirred under reflux for 2 hours. The obtained slurry was cooled to 60 ° C., and a solution obtained by dissolving 11.2 parts of cesium bicarbonate in 30 parts of pure water was added and stirred for 15 minutes. Next, a solution prepared by dissolving 10 parts of ammonium nitrate in 30 parts of pure water was added, and the mixture was further stirred for 15 minutes.
[0021]
The obtained slurry containing the catalyst component was dried using a cocurrent flow (mixed flow) spray dryer at a dryer inlet temperature of 320 ° C. To 100 parts of the obtained dried product, 60 parts of ethyl alcohol was added and mixed well with a high-speed stirring mixer. This mixture was dried in a box-type hot air dryer adjusted to 50 ° C. for 48 hours, and then sized using a sizing machine. 3 parts of graphite was added to and mixed with 100 parts of the dry powder thus obtained, and formed into a ring shape having an outer diameter of 6 mm, an inner diameter of 3 mm, and a length of 5 mm by a tableting machine. This tableting molded product was heat-treated at 380 ° C. for 5 hours under air flow, so that the composition was P _1.3 Mo ₁₂ V _0.7 Cu _0.1 Cs _1.
The resulting catalyst was obtained.
[0022]
Reaction was performed by passing a mixed gas of 5% methacrolein, 10% oxygen, 30% water vapor, and 55% nitrogen (volume%) in a fixed bed reactor filled with this catalyst at a reaction temperature of 290 ° C. with a contact time of 3.6 seconds. I let you. The product of this reaction was collected and analyzed by gas chromatography. The reaction rate of methacrolein was 84.7%, the selectivity of methacrylic acid was 85.0%, and the single flow yield of methacrylic acid was 72. 0%.
[0023]
[Comparative Example 1]
In Example 1, a catalyst was produced and reacted in the same manner as in Example 1 except that the dry powder was directly sized without mixing ethyl alcohol, and the reaction rate of methacrolein was 83.0%. The selectivity for methacrylic acid was 84.7% and the single stream yield of methacrylic acid was 70.3%.
[0024]
[Comparative Example 2]
In Example 1, except that the amount of ethyl alcohol used was 20 parts, a catalyst was produced and reacted in the same manner as in Example 1. As a result, the reaction rate of methacrolein was 83.1% and methacrylic acid was selected. The rate was 84.8%, the single stream yield of methacrylic acid was 70.5%, and almost no mixing effect of the catalyst dry powder and ethyl alcohol was observed.
[0025]
[Example 2]
100 parts of ammonium paramolybdate, 2.8 parts of ammonium metavanadate, and 9.2 parts of cesium nitrate were dissolved in 300 parts of pure water. To this was added a solution prepared by dissolving 7.6 parts of 85% by weight phosphoric acid in 10 parts of pure water and a solution prepared by dissolving 1.1 parts of 60% by weight arsenic acid solution in 10 parts of pure water. Warm up. Subsequently, a solution obtained by dissolving 1.7 parts of copper nitrate, 7.6 parts of ferric nitrate, 1.4 parts of zinc nitrate and 1.8 parts of magnesium nitrate in 80 parts of pure water was added. The mixture was further stirred at 100 ° C. for 15 minutes.
[0026]
The obtained slurry containing the catalyst component was dried with a drum dryer, 40 parts of isobutyl alcohol and 1 part of hydroxypropylcellulose were added to 100 parts of the obtained dried product, and mixed well with a double-arm kneader. This mixture was dried in a box-type hot air dryer adjusted to 70 ° C. for 48 hours, and then sized with a sizing machine. 2 parts of graphite was added to and mixed with 100 parts of the dry powder thus obtained, and formed into a cylindrical shape having an outer diameter of 4 mm and a length of 4 mm by a tableting machine. The composition of P _1.4 Mo ₁₂ V _0.5 Fe _0.4 Cu _0.15 As _0.1 Cs ₁ Mg _0.15 Zn _0.1 was prepared by heat-treating this tablet-molded product at 380 ° C. for 5 hours under air flow.
The resulting catalyst was obtained.
[0027]
Using this catalyst, the reaction was carried out under the same conditions as in Example 1. As a result, the reaction rate of methacrolein was 86.3%, the selectivity of methacrylic acid was 85.8%, and the single stream yield of methacrylic acid was 74. 0.0%.
[0028]
[Comparative Example 3]
In Example 2, the catalyst was produced and reacted in the same manner as in Example 2 except that the dry powder was directly sized without mixing isobutyl alcohol, and the reaction rate of methacrolein was 84.5%. The selectivity of methacrylic acid was 85.4%, and the single flow yield of methacrylic acid was 72.2%.
[0029]
[Example 3]
100 parts of molybdenum trioxide, 4.1 parts of ammonium metavanadate and 6.7 parts of 85% by weight phosphoric acid were mixed with 800 parts of pure water. After heating and stirring for 3 hours under reflux, a solution in which 1.4 parts of copper nitrate was dissolved in 20 parts of pure water, a solution in which 0.8 part of manganese nitrate was dissolved in 10 parts of pure water, 5.6 parts of bismuth nitrate A bismuth nitrate uniform solution obtained by adding 5.7 parts of 60% by weight nitric acid and 40 parts of pure water and 2.5 parts of antimony trioxide were added, and the mixture was again stirred under reflux for 2 hours. The obtained mixed solution containing the catalyst component was cooled to 50 ° C., 26.0 parts of 50% cesium hydroxide solution was added, and the mixture was stirred for 15 minutes. Next, 10 parts of ammonium nitrate was dissolved in 30 parts of pure water, and the mixture was further stirred for 15 minutes.
[0030]
The obtained slurry containing the catalyst component was dried using a slurry dryer at a hot air blowing temperature of 300 ° C., and 3 parts of water and 80 parts of methyl alcohol were added to 100 parts of the resulting dried product. And mixed well with a twin-screw blade kneader. This mixture was dried in a box-type hot air dryer adjusted to 50 ° C. for 48 hours, and then sized using a sizing machine. 3 parts of graphite was added to and mixed with 100 parts of the dry powder thus obtained, and formed into a cylindrical shape having an outer diameter of 5 mm and a length of 3 mm by a tableting machine. This tablet-molded product was heat-treated at 380 ° C. for 5 hours under air flow, and the composition was P ₁ Mo ₁₂ V _0.6 Sb _0.3 Cu _0.1 Bi _0.2 Cs _1.5 Mn _0.05
The resulting catalyst was obtained.
[0031]
Using this catalyst, the reaction was carried out under the same conditions as in Example 1. As a result, the reaction rate of methacrolein was 87.5%, the selectivity of methacrylic acid was 88.3%, and the single flow yield of methacrylic acid was 77. 3%.
[0032]
[Comparative Example 4]
In Example 3, a catalyst was produced and reacted in the same manner as in Example 3 except that the dry powder was directly sized without mixing methyl alcohol. The reaction rate of methacrolein was 85.3%, The selectivity of methacrylic acid was 88.1%, and the single flow yield of methacrylic acid was 75.1%.
[0033]
【The invention's effect】
According to the method for producing a catalyst of the present invention, a catalyst capable of synthesizing an unsaturated carboxylic acid in a high yield by gas phase catalytic oxidation of an unsaturated aldehyde is obtained.

Claims (1)

  A method for producing a catalyst containing at least phosphorus, molybdenum, and vanadium, which is used for synthesizing an unsaturated carboxylic acid by vapor-phase catalytic oxidation of an unsaturated aldehyde, obtained from a mixed solution or an aqueous slurry containing a catalyst component In a method of dry-molding a dry powder and then heat-treating, the dry powder is at least 30 parts by weight of methyl alcohol, ethyl alcohol, 100 parts by weight of a dry solution of a mixed solution or an aqueous slurry containing a catalyst component, A method for producing an unsaturated carboxylic acid synthesis catalyst, comprising mixing at least one organic compound selected from the group consisting of propyl alcohol, butyl alcohol, and acetone, followed by drying.