JP4497457B2 - Method for producing catalyst for production of methacrylic acid ester - Google Patents

Description

  The present invention relates to a catalyst for producing a methacrylate ester by reacting propionate ester with formaldehyde and / or a formaldehyde derivative in a gas phase, a method for producing the catalyst, and a method for producing the methacrylate ester.

For example, Patent Document 1 contains a regulator element such as magnesium and zirconium and an alkali metal such as cesium as a catalyst used in a method for producing a methacrylic ester by vapor-phase contact reaction between methyl propionate and formaldehyde. Catalysts containing porous high surface area silica are described. In addition, it is described that silica having a specific surface area or more is used for the production of the catalyst. Examples of such silica include silica gel, precipitated silica gel, and aggregated high heat silica. Such silica typically contains more than 0.2 atoms of sodium per 100 atoms of silicon. Furthermore, since paragraph 0004 of Patent Document 1 describes that the activity decreases when the alkali metal decreases, it has not been conventionally performed to employ special silica having a low sodium content as a silicon source.
Japanese translation of PCT publication No. 2002-511336

  However, the catalyst described in Patent Document 1 has a problem that the yield of the target methacrylate ester is low.

  An object of the present invention is to provide a catalyst for producing a methacrylic acid ester in a high yield by gas phase catalytic reaction of propionic acid ester with formaldehyde and / or a formaldehyde derivative, a method for producing the catalyst, and a high methacrylic acid ester. The object is to provide a method for producing in a yield.

The present invention is as follows.
[1] In a method for producing a catalyst having a composition represented by the formula (1) for producing a methacrylic acid ester by gas phase catalytic reaction of propionic acid ester with formaldehyde and / or a formaldehyde derivative, sodium as a silicon source Uses a silicon source of 0.2 atoms or less per 100 atoms of silicon.
Si _a Cs _b O _d (1)
(In the formula (1), Si, Cs and O represent silicon, cesium and oxygen, respectively. A, b and d represent the atomic ratio of each element, and when a = 100, b = 0.01-5. , D is the atomic ratio of oxygen necessary to satisfy the valence of other components.)
Or
In the method for producing a catalyst having a composition represented by the formula (2) for producing a methacrylic acid ester by vapor-phase catalytic reaction of propionic acid ester with formaldehyde and / or a formaldehyde derivative, sodium is used as a silicon source. The manufacturing method of the catalyst for methacrylic acid ester manufacture characterized by using the silicon source of 0.2 atom or less per atom.
Si _a Cs _b X _c O _d (2)
In (Equation (2), Si, Cs and O represent respectively silicon, cesium and oxygen, X is at least one element Bareru selected from titanium and Contact di Rukoniumu .a, b, c, d each element Where a = 100, b = 0.01-5, c = 0.01-3, and d is the atomic ratio of oxygen necessary to satisfy the valences of the other components. .)

[2] A catalyst for producing a methacrylic ester produced by the method of [1].

[3] A method for producing a methacrylic acid ester, wherein the catalyst of [2] is used in a method for producing a methacrylic acid ester by reacting propionic acid ester with formaldehyde and / or a formaldehyde derivative in a gas phase. .

  ADVANTAGE OF THE INVENTION According to this invention, the catalyst which can manufacture a methacrylic acid ester with a high yield can be manufactured. Further, when a gas phase catalytic reaction of propionic acid ester with formaldehyde and / or formaldehyde derivative is carried out using the catalyst for producing methacrylic acid ester of the present invention, methacrylic acid ester can be produced in high yield.

  The composition of the methacrylic acid ester production catalyst produced in the present invention is essentially composed of silicon and cesium as shown in the formula (1).

  As the silicon source used for the production of the catalyst, for example, silicon dioxide, silicic acid, silica gel, colloidal silica and the like can be used. Of these, colloidal silica is preferred. In the present invention, the sodium content of the silicon source is 0.2 atom or less per 100 atoms of silicon. Preferably, it is 0.1 atom or less per 100 atoms of silicon. As the sodium content is lower, a catalyst capable of producing a methacrylic acid ester in a higher yield is obtained.

  In the case of colloidal silica, the average diameter of the primary particles of the silicon source is preferably 0.1 to 30 nm. The activity tends to be stronger as the average diameter of the primary particles is smaller.

  As the cesium source used for the production of the catalyst, for example, cesium carbonate, cesium hydroxide, cesium nitrate and the like can be used. Among these, cesium carbonate and cesium hydroxide are preferable in terms of catalyst activity and selectivity.

  The atomic ratio of silicon, cesium, and oxygen in the catalyst is as follows: when a (atomic ratio of silicon) = 100, as shown in formula (1), b (atomic ratio of cesium) = 0.01-5, Is b = 0.05-3. d is an atomic ratio of oxygen satisfying the valence of other components.

  The catalyst manufactured by this invention may contain 1 type, or 2 or more types of elements other than the element shown by Formula (1). Such optional elements that can be added are not particularly limited. As a preferred catalyst composition containing an optional element, the above formula (2) can be mentioned. The catalyst manufactured by this invention may contain 1 type, or 2 or more types of elements other than the element shown by Formula (2).

  In the formula (2), when the atomic ratio of silicon, cesium, X element and oxygen is a (atomic ratio of silicon) = 100, b (atomic ratio of cesium) and d (atomic ratio of oxygen) are expressed by formula (1) And c = 0.3-1, preferably c = 0.03-2.

  As the X element source used for the production of the catalyst, for example, nitrates, carbonates, oxides, hydroxides, acetates, chlorides and the like can be used. Of these, nitrates and carbonates are preferred in terms of activity and selectivity.

  The catalyst raw material may be used alone or in combination of two or more for each element.

  The method for producing the catalyst of the present invention is not particularly limited, and for example, production methods such as a precipitation method, a coprecipitation method, and an oxide mixing method can be used. As a specific production method, for example, a solution or slurry (hereinafter referred to as catalyst raw material mixture) in which a necessary amount of an element source of each constituent element of the catalyst is dissolved or suspended in a solvent such as water is prepared, The method of drying this solution or slurry and heat-treating the obtained dried material is mentioned.

  The catalyst raw material mixture is prepared, for example, by mixing an aqueous solution or aqueous slurry of a silicon source such as colloidal silica, a cesium source such as cesium carbonate, and an aqueous solution or aqueous slurry of an X element source such as zirconium nitrate, or a solid material. be able to. The catalyst raw material mixture is preferably prepared while stirring. Moreover, although the temperature at the time of preparation is usually room temperature, you may heat to the grade which boils as needed.

  Examples of the method for drying the catalyst raw material mixture include evaporation to dryness, spray drying, drum drying, and airflow drying. Among these, the spray drying method is suitable for industrially producing a catalyst having a uniform property. The dryer used for drying is appropriately selected depending on the drying method. Although drying conditions, such as drying temperature, are not specifically limited, It selects suitably by the target drying state.

  The obtained dried product is appropriately pulverized, appropriately molded, and then heat treated to obtain a catalyst for producing a methacrylic ester. The method and conditions for the heat treatment are not particularly limited, and for example, known methods and conditions can be applied. The optimum conditions for the heat treatment vary depending on the catalyst raw material, catalyst composition, catalyst preparation method, etc., and cannot be generally stated, but usually 200 to 500 ° C. under a flow of oxygen-containing gas such as air or under the flow of an inert gas. Preferably it is 300-450 degreeC, and is 0.5 hour or more, Preferably it is 1 to 40 hours. Examples of the inert gas include nitrogen, carbon dioxide, helium, and argon.

  The catalyst may be unsupported, but may be supported on a support such as silicon dioxide, magnesium oxide, and titanium oxide. Examples of the supporting method include a method of supporting at the stage of the catalyst raw material mixture, a method of supporting a dried product, and a method of supporting a heat-treated catalyst.

  Next, the manufacturing method of the methacrylic acid ester of this invention is demonstrated. In the method for producing a methacrylic acid ester of the present invention, a propionic acid ester and formaldehyde and / or a formaldehyde derivative are reacted in a gas phase in the presence of the catalyst obtained as described above. At that time, methacrylic acid may be slightly co-produced.

  Usually, the reaction is carried out in a fixed bed reactor, but it can also be carried out in a fluidized bed reactor. When a fixed bed reactor is used, the catalyst layer may be one layer or two or more layers.

  The raw material gas brought into contact with the catalyst includes propionic acid esters and formaldehyde and / or formaldehyde derivatives.

  Propionic acid ester is selected according to the target methacrylic acid ester. 1-5 are preferable and, as for carbon number of the alcohol residue of propionate, 1-3 are more preferable. Examples of the propionic acid ester include methyl propionate for the production of methyl methacrylate, ethyl propionate for the production of ethyl methacrylate, and butyl propionate for the production of butyl methacrylate. Although the density | concentration of propionic acid ester in source gas can be changed in the wide range, 1-90 mol% is preferable and 5-60 mol% is more preferable.

  The formaldehyde derivative means a compound that gives formaldehyde in a reaction field such as methylal, trioxane, paraformaldehyde, and the like. Formaldehyde and / or formaldehyde derivatives (hereinafter referred to collectively as formaldehydes) may be used singly or in combination of two or more.

  The molar ratio of propionic acid ester to formaldehyde in the raw material gas (formaldehyde conversion in the case of formaldehyde derivatives) is preferably propionic acid ester: formaldehydes = 1: 20 to 20: 1, and 1:10 to 10: 1. More preferred.

  The source gas may contain an inert gas such as nitrogen, water vapor, methanol or the like in addition to propionate and formaldehyde. A small amount of oxygen may be included, but it is preferable not to include it.

  The inert gas concentration of the raw material gas is preferably 1 to 95% by volume, more preferably 5 to 90% by volume. The water vapor concentration of the raw material gas is preferably 0.01 to 20% by volume, more preferably 0.05 to 10% by volume. The methanol concentration of the raw material gas can be varied within a wide range, but is preferably 1 to 90% by volume, more preferably 5 to 60% by volume.

  Each component of the raw material gas may be supplied as a raw material gas to the reactor as a raw material gas, or may be separately supplied to the reactor and mixed in the reactor to obtain the raw material gas.

  The reaction pressure of the gas phase contact reaction is usually from atmospheric pressure to several atmospheres. The reaction temperature is preferably 200 to 500 ° C, more preferably 250 to 450 ° C. The contact time of the source gas is preferably 1.5 to 50 seconds, and more preferably 5 to 40 seconds.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated in more detail, this invention is not limited to these Examples.

  “Parts” in Examples and Comparative Examples means parts by mass. The catalyst composition was determined from plasma emission analysis (ICP) and atomic absorption analysis. The compounds in the raw material gas and the reaction gas were quantified by gas chromatography. However, formaldehyde was analyzed by iodometric titration.

In addition, the conversion rate of propionic acid ester, the selectivity of methacrylic acid ester, the selectivity of methacrylic acid, and the yield of methacrylic acid ester are defined as follows.
Conversion rate of propionate (%) = (B / A) × 100
Methacrylate ester selectivity (%) = (C / B) × 100
Methacrylic acid selectivity (%) = (D / B) × 100
Methacrylate yield (%) = (C / A) × 100
Here, A is the number of moles of propionic acid ester supplied, B is the number of moles of reacted propionic acid ester, C is the number of moles of methacrylic acid ester produced, and D is the number of moles of methacrylic acid produced.

[Example 1]
An aqueous solution in which 2.8 parts of cesium carbonate is dissolved in 10 parts of pure water in 225 parts of silica sol comprising 20 mass% SiO ₂ aqueous solution containing 0.0094 atoms of sodium per 100 atoms of silicon and having an average primary particle diameter of 15 nm. And stirred well. This liquid mixture was evaporated to dryness to obtain a solid. The obtained solid was dried at 150 ° C. and then pulverized to a size of 7 to 20 mesh. The obtained pulverized product was heat-treated at 450 ° C. for 3 hours under air flow. The composition of the obtained catalyst other than oxygen (hereinafter the same) was Si ₁₀₀ Cs _2.26 .

  The catalyst was charged into a fixed bed reactor, and a raw material gas of methyl propionate: methanol: formaldehyde: water: nitrogen = 1: 1.45: 0.19: 0.46: 5.35 (molar ratio) was added to 395 mmol / The reaction was carried out at hr, under atmospheric pressure, reaction temperature 350 ° C., and contact time 12 seconds. The results are shown in Table 1.

[Example 2]
In Example 1, Example 1 was carried out in the same manner as in Example 1 except that 20 wt% SiO ₂ aqueous solution containing 0.094 atoms of sodium per 100 atoms of silicon as the silica sol and having an average primary particle diameter of 15 nm was used. A catalyst having the same composition as in Example 1 was prepared and reacted. The results are shown in Table 1.

[Example 3]
In Example 1, Example 1 was carried out in the same manner as in Example 1 except that a 20 wt% SiO ₂ aqueous solution containing 0.135 atoms of sodium per 100 atoms of silicon as the silica sol and having an average primary particle diameter of 15 nm was used. A catalyst having the same composition as in Example 1 was prepared and reacted. The results are shown in Table 1.

[Comparative Example 1]
Example 1 is the same as Example 1 except that 0.38 atom of sodium per 100 atoms of silicon is used as the silica sol and a 20 mass% SiO ₂ aqueous solution having an average primary particle diameter of 15 nm is used. A catalyst having the same composition as in Example 1 was prepared and reacted. The results are shown in Table 1.

[Comparative Example 2]
In Example 1, Example 1 was carried out in the same manner as in Example 1, except that a 20 mass% SiO ₂ aqueous solution containing 2.16 atoms of sodium per 100 atoms of silicon as the silica sol and having an average primary particle diameter of 15 nm was used. A catalyst having the same composition as in Example 1 was prepared and reacted. The results are shown in Table 1.

[Comparative Example 3]
In Example 1, Example 1 was used in the same manner as in Example 1 except that a 20 mass% SiO ₂ aqueous solution containing 7.5 atoms of sodium per 100 atoms of silicon as the silica sol and having an average primary particle diameter of 5 nm was used. A catalyst having the same composition as in Example 1 was prepared and reacted. The results are shown in Table 1.

[Example 4]
In Example 1, an aqueous solution in which 5.1 parts of 50% cesium hydroxide was dissolved in 10 parts of pure water and 2.0 parts of zirconium nitrate in water instead of an aqueous solution in which 2.8 parts of cesium carbonate were dissolved in 10 parts of pure water. A catalyst was prepared in the same manner as in Example 1 except that a solution dissolved in 50 parts was added to silica sol. The composition of the obtained catalyst was Si ₁₀₀ Cs _2.26 Zr _1.0 . And it reacted like Example 1 using this catalyst. The results are shown in Table 1.

[Comparative Example 4]
In Example 4, Example 4 was carried out in the same manner as Example 4 except that a 20 mass% SiO ₂ aqueous solution containing 0.38 atoms of sodium per 100 atoms of silicon as the silica sol and having an average primary particle diameter of 15 nm was used. A catalyst having the same composition as in Example 1 was prepared and reacted. The results are shown in Table 1.

[Comparative Example 5]
In Example 4, Example 4 was carried out in the same manner as Example 4 except that a 20 mass% SiO ₂ aqueous solution containing 1.92 atoms of sodium per 100 atoms of silicon as the silica sol and having an average primary particle diameter of 45 nm was used. A catalyst having the same composition as in Example 1 was prepared and reacted. The results are shown in Table 1.

Claims (5)

In a method for producing a catalyst having a composition represented by the formula (1) for producing a methacrylic acid ester by vapor-phase catalytic reaction of propionic acid ester with formaldehyde and / or a formaldehyde derivative, sodium is used as a silicon source. The manufacturing method of the catalyst for methacrylic acid ester manufacture characterized by using the silicon source of 0.2 atom or less per atom.
Si _a Cs _b O _d (1)
(In the formula (1), Si, Cs and O represent silicon, cesium and oxygen, respectively. A, b and d represent the atomic ratio of each element, and when a = 100, b = 0.01-5. , D is the atomic ratio of oxygen necessary to satisfy the valence of other components.) In the method for producing a catalyst having a composition represented by the formula (2) for producing a methacrylic acid ester by vapor-phase catalytic reaction of propionic acid ester with formaldehyde and / or a formaldehyde derivative, sodium is used as a silicon source. The manufacturing method of the catalyst for methacrylic acid ester manufacture characterized by using the silicon source of 0.2 atom or less per atom .
Si _a Cs _b X _c O _d (2)
In (Equation (2), Si, Cs and O represent respectively silicon, cesium and oxygen, X is at least one element Bareru selected from titanium and Contact di Rukoniumu .a, b, c, d each element Where a = 100, b = 0.01 to 5, c = 0.01 to 3, and d is the atomic ratio of oxygen necessary to satisfy the valences of the other components. .) 3. The method for producing a catalyst for producing a methacrylic acid ester according to claim 1, wherein a silicon source having a sodium content of 0.135 atoms or less per 100 atoms of silicon is used. The catalyst for methacrylic acid ester manufacture manufactured by the method in any one of Claims 1-3. A method for producing a methacrylic acid ester, wherein the catalyst according to claim 4 is used in a method for producing a methacrylic acid ester by reacting propionic acid ester with formaldehyde and / or a formaldehyde derivative in a gas phase.