Method for producing cresol or benzaldehyde, and catalyst

Abstract

To provide a novel method for producing cresol or benzaldehyde, which enables simple and efficient production of cresol or benzaldehyde through direct oxidation of toluene.SOLUTION: A method for producing cresol or benzaldehyde comprises an oxidation step of oxidizing toluene through contact between a catalyst and toluene in the presence of oxygen to produce at least one of cresol and benzaldehyde, wherein the catalyst comprises a support containing crystalline aluminosilicate and a supported metal carried on the support, and the supported metal contains copper.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for producing cresol or benzaldehyde, and a catalyst. [Background technology]

[0002] Cresol and benzaldehyde are basic chemicals that are useful in a wide range of fields. Conventionally, these compounds are produced using, for example, toluene as a raw material.

[0003] As a method for producing m- and p-cresol from toluene, a method (cymene method) is known in which toluene is reacted with propylene to form cymene, which is then oxidized to form cymene hydroperoxide, and then cymene hydroperoxide is decomposed in the presence of an acid to obtain m- and p-cresol (see, for example, Non-Patent Document 1).

[0004] As a method for producing benzaldehyde from toluene, there is known a method in which toluene is chlorinated to form benzal chloride, and then the benzal chloride is hydrolyzed to obtain benzaldehyde (see, for example, Patent Documents 1 to 3). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 59-134737 [Patent Document 2] Japanese Patent Application Publication No. 60-84240 [Patent Document 3] Japanese Patent Application Publication No. 62-207239 [Non-patent literature]

[0006] [Non-Patent Document 1] "Development and Industrialization of the Sumika Cresol Manufacturing Process," Journal of the Society of Organic Synthetic Chemistry, Vol. 30, No. 3, 1972, pp. 206-209 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the above-mentioned method for producing cresol from toluene requires multiple reaction stages before cresol is obtained, which requires capital investment, consumes a large amount of energy, and requires a large amount of acid.

[0008] On the other hand, the above-mentioned method for producing benzaldehyde from toluene also requires multiple reactions to obtain benzaldehyde, which requires investment in equipment, consumes a large amount of energy, and requires a large amount of chlorine. In addition, when toluene is directly oxidized to produce benzaldehyde, the reaction does not stop at the production of benzaldehyde, but continues to produce benzoic acid.

[0009] Therefore, an object of the present invention is to provide a novel process for producing cresol or benzaldehyde, which can simply and efficiently produce cresol or benzaldehyde by direct oxidation of toluene, and a catalyst used therein. [Means for solving the problem]

[0010] In order to solve the above problems, the present invention provides the following method for producing cresol or benzaldehyde, and catalyst.

[0011] [1] A method for producing cresol or benzaldehyde, comprising an oxidation step of contacting a catalyst with toluene in the presence of oxygen to oxidize the toluene to produce at least one of cresol and benzaldehyde, the catalyst having a carrier containing a crystalline aluminosilicate and a supported metal supported on the carrier, the supported metal containing copper. [2] The method according to [1] above, wherein the content of copper in the catalyst is 0.3 to 2.0 mass % based on the total amount of the catalyst. [3] The method according to [1] or [2] above, wherein the crystalline aluminosilicate is a pentasil-type zeolite. [4] The method according to any one of the above [1] to [3], wherein the crystalline aluminosilicate is an MFI type zeolite. [5] The method according to the above [4], wherein the ratio of the number of silicon atoms to the number of aluminum atoms in the MFI zeolite is 10 to 100. [6] The method according to any one of the above [1] to [5], wherein the oxidation step is carried out in an environment having an oxygen partial pressure of 0.1 to 30.0 kPa. [7] A catalyst used for producing at least one of cresol and benzaldehyde by oxidizing toluene, the catalyst having a carrier containing a crystalline aluminosilicate and a supported metal supported on the carrier, the supported metal containing copper. [8] The catalyst according to [7] above, wherein the copper content is 0.3 to 2.0 mass % based on the total amount of the catalyst. [9] The catalyst according to [7] or [8] above, wherein the crystalline aluminosilicate is a pentasil-type zeolite.

[10] The catalyst according to any one of the above [7] to [9], wherein the crystalline aluminosilicate is an MFI type zeolite.

[11] The catalyst according to the above

[10] , wherein the MFI zeolite has a silicon / aluminum atomic ratio of 10 to 100. Effect of the Invention

[0012] According to the present invention, there can be provided a novel process for producing cresol or benzaldehyde simply and efficiently by direct oxidation of toluene, and a catalyst used therein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Preferred embodiments of the present invention will now be described in detail.

[0014] <Catalyst> The catalyst according to the present embodiment is a catalyst used for oxidizing toluene to produce at least one of cresol and benzaldehyde, and has a carrier containing crystalline aluminosilicate and a supported metal supported on the carrier. The supported metal contains copper. The catalyst has a structure in which copper is supported on a carrier containing crystalline aluminosilicate, and thus toluene can be directly oxidized by contacting the catalyst with toluene in the presence of oxygen. Therefore, by using the catalyst, cresol or benzaldehyde can be easily and efficiently produced from toluene in one step without going through multiple steps as in conventional methods, and without requiring a large amount of acid or chlorine and a large amount of energy. In addition, by using the catalyst, cresol or benzaldehyde can be produced from toluene with high yield and high selectivity. The reason why toluene can be efficiently directly oxidized by using the catalyst is not clear, but it is presumed that the oxygen activation effect of copper is the cause.

[0015] Crystalline aluminosilicate is a metal oxide composed of three elements, aluminum, silicon, and oxygen. Crystalline aluminosilicate can also contain other metal elements. Examples of metal elements that can coexist include titanium, lanthanum, and manganese.

[0016] The crystallinity of an aluminosilicate can be estimated by the ratio of 4-coordinate aluminum atoms to the total aluminum atoms, which is 27 The ratio of tetracoordinated aluminum to the total amount of aluminum in the crystalline aluminosilicate used in the present invention may be 50% by mass or more, 70% by mass or more, or 80% by mass or more.

[0017] As the crystalline aluminosilicate, so-called zeolite can be used. The zeolite may be a pentasil type zeolite. The pentasil type zeolite is a zeolite having a structure in which 10-membered oxygen rings are linked. Examples of the pentasil type zeolite include MFI type zeolite and MEL type zeolite. Among these, the crystalline aluminosilicate is preferably MFI type zeolite. The above three alphabetical letters are the structure codes of zeolite defined by the Structure Commission of the International Zeolite Association (IZA-SC). Examples of the MFI type zeolite include ZSM-5 and silicalite.

[0018] In MFI zeolite, the atomic ratio of silicon / aluminum (Si / Al) is preferably 10 to 100, more preferably 11 to 75, further preferably 12 to 40, and particularly preferably 14 to 25. When the atomic ratio of Si / Al is 10 or more, the acidity can be prevented from becoming too strong, and the occurrence of side reactions caused by strong acidity tends to be prevented, and when it is 100 or less, the acid sites of the support become sufficient, and the reaction tends to be promoted.

[0019] The above-mentioned crystalline aluminosilicates may be used alone or in combination of two or more kinds.

[0020] The carrier containing the crystalline aluminosilicate may be in the form of a powder or a molded body. When the carrier is made into a molded body, a method of molding a mixture of the crystalline aluminosilicate and a binder and firing the molded body can be mentioned. There is no particular limitation on the binder to be used, and examples thereof include alumina, silica, silica alumina, titania, magnesia, etc. In addition, the molded body can be formed by a method other than the above.

[0021] The supported metal contains at least copper. The supported metal may be supported on the surface and / or within the pores of the support.

[0022] The copper content (supported amount) in the catalyst is preferably 0.3 to 2.0 mass% based on the total amount of the catalyst, more preferably 0.4 to 1.5 mass%, further preferably 0.6 to 1.2 mass%, and particularly preferably 0.8 to 1.0 mass%. When the copper content is less than 0.3 mass%, the activity of the catalyst does not increase sufficiently compared to when the content is 0.3 mass% or more, and the reaction tends to proceed less smoothly when reacted with toluene, and when the content exceeds 2.0 mass%, the acid site of the support is easily destroyed due to the increase in the supported metal compared to when the content is 2.0 mass% or less, and when cresol or benzaldehyde is produced from toluene using the catalyst, the yield and selectivity of these compounds tend to decrease.

[0023] The catalyst may contain a metal other than copper. The other metals may be used alone or in combination of two or more.

[0024] <Catalyst manufacturing method> The catalyst can be produced, for example, by a step of supporting copper on a carrier, which can be carried out by a conventional method such as impregnation of the carrier with a copper-containing solution or ion exchange.

[0025] When the impregnation method is adopted, for example, the catalyst can be produced through a process of impregnating a support with an aqueous copper salt solution, drying and calcining the support to support copper. As the impregnation method, a method such as normal pressure impregnation, reduced pressure impregnation, and pressurized impregnation can be used.

[0026] The copper salt solution may be an aqueous solution of copper (II) acetate, an aqueous solution of copper (II) chloride, etc. The concentration of the copper salt solution is not particularly limited, but may be, for example, 3.0×10 -3 ~3.0×10 -2 It can be M.

[0027] Drying after the impregnation can be carried out, for example, for 5 to 72 hours at 100 to 200° C. Drying can be carried out under atmospheric conditions.

[0028] After copper is supported, the catalyst can be fired for 1 to 24 hours at, for example, 700 to 1000° C. The firing can be carried out under atmospheric conditions.

[0029] <Production method of cresol or benzaldehyde> The method for producing cresol or benzaldehyde according to this embodiment includes an oxidation step of contacting toluene with the above-described catalyst in the presence of oxygen to oxidize toluene and produce at least one of cresol and benzaldehyde.

[0030] The method for oxidizing toluene is not particularly limited as long as it is a method that can bring toluene into contact with a catalyst in the presence of oxygen. For example, a method using a fixed-bed flow tubular reactor can be mentioned.

[0031] When a fixed-bed flow tubular reactor is used, the reactor is filled with a catalyst, toluene is introduced into the reactor and vaporized by heating, and the toluene is caused to flow through the region filled with the catalyst together with oxygen, thereby allowing the oxidation reaction of toluene to proceed.

[0032] The oxidation step is preferably carried out in an environment with an oxygen partial pressure of 0.1 to 30.0 kPa, more preferably 0.3 to 20.0 kPa, further preferably 0.5 to 10.0 kPa, and particularly preferably 0.5 to 3.0 kPa. When the oxygen partial pressure is 0.1 kPa or more, the oxidation reaction is easily allowed to proceed, and when it is 30.0 kPa or less, the yield and selectivity of cresol and benzaldehyde can be improved.

[0033] In addition, the ratio of benzaldehyde and cresol obtained can be adjusted by adjusting the oxygen partial pressure in the oxidation step. When it is desired to improve the yield of cresol rather than that of benzaldehyde, the oxygen partial pressure in the oxidation step is preferably low, and is preferably 0.1 to 10.0 kPa, more preferably 0.2 to 5.0 kPa, and particularly preferably 0.5 to 3.0 kPa. On the other hand, when it is desired to improve the yield of benzaldehyde rather than that of cresol, the oxygen partial pressure in the oxidation step is preferably high, and is preferably 1.0 to 30.0 kPa, more preferably 5.0 to 20.0 kPa, and particularly preferably 8.0 to 15.0 kPa.

[0034] The oxidation step can be carried out in a heated state at 300 to 500°C, and is preferably carried out in a heated state at 350 to 450°C, from the viewpoint of promoting the oxidation of toluene and improving the yield and selectivity of cresol and benzaldehyde.

[0035] In a fixed-bed flow tubular reactor, the ratio of the mass W of the catalyst to the supply rate (supply amount / hour) F of toluene (hereinafter referred to as "W / F") is not particularly limited, but may be 200 to 500 g-cat·min / mol, 220 to 480 g-cat·min / mol, or 236 to 472 g-cat·min / mol. When W / F is 200 g-cat·min / mol or more, the contact time between toluene and the catalyst can be sufficiently secured, so that the oxidation of toluene tends to proceed easily. When W / F is 500 g-cat·min / mol or less, side reactions tend to be suppressed.

[0036] In the fixed-bed flow tubular reactor, toluene can be supplied, for example, in a heated vaporized state under the flow of oxygen-containing inert gas. At this time, the gas partial pressure ratio of oxygen-containing inert gas to toluene at the reaction temperature is not particularly limited, but from the viewpoint of promoting the oxidation of toluene, oxygen-containing inert gas:toluene=5:0.1 to 5:0.3, or 5:0.15 to 5:0.25 may be used.

[0037] Before supplying toluene, the catalyst may be pretreated. For example, the catalyst may be heated at 400 to 500°C for 0.5 to 5 hours in air flow as the pretreatment. This makes it possible to remove impurities adhering to the catalyst. In addition, from the viewpoint of eliminating the influence of residual oxygen, the inside of the reactor may be purged with nitrogen for 0.5 to 1 hour.

[0038] The reaction product can be recovered as a liquid by cooling it to a temperature below its boiling point using a refrigerant.

[0039] According to the above method, cresol or benzaldehyde can be produced simply and efficiently in one step from toluene without going through multiple steps, and without requiring a large amount of acid or chlorine and a large amount of energy. The product contains at least one of cresol and benzaldehyde, but may contain two or more. Cresol contains one of p-cresol and o-cresol, but may contain two or more. According to the production method of this embodiment, at least one of cresol and benzaldehyde can be produced with high yield and high selectivity, and in particular, p-cresol can be produced with high yield and high selectivity. The ratio of cresol and benzaldehyde in the product can also be changed by adjusting the catalyst configuration, the conditions of the oxidation step, etc. EXAMPLES

[0040] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0041] [Example 1] <Catalyst Preparation> 10.5g of NaAlO2, 2g of NaOH, 20g of TPAOH (tetrapropylammonium hydroxide), and 70g of silica gel were added to 53g of ion-exchanged water, and the mixture was stirred and mixed at room temperature for 3 hours, dried at 90°C for 5 hours, hydrothermally synthesized at 180°C for 72 hours, and calcined at 600°C for 5 hours to obtain NaZSM-5. Furthermore, NaZSM-5 was ion-exchanged with 3mol / L of ammonium nitrate, and then calcined at 550°C for 5 hours to obtain HZSM-5 (confirmed to have an MFI structure by X-ray analysis, Si / Al atomic ratio: 14). 10g of the obtained HZSM-5 zeolite was dissolved in an aqueous solution of copper(II) chloride (concentration 7.14×10 -3 The catalyst was impregnated with 50 mL of HZSM-5 zeolite (HZSM-5 zeolite) and ion-exchanged at 90°C for 8 hours, washed with ion-exchanged water, and dried at 130°C for 16 hours. After drying, the catalyst was calcined at 1000°C for 5 hours under an air flow of N2 gas at 100 mL / min and O2 gas at 25 mL / min, and then dried to obtain a catalyst in which copper was supported on HZSM-5 zeolite. The copper content (supported amount) in the obtained catalyst was 0.71 mass%. Note that, since the raw materials used in the production of the catalyst are not discharged outside the system except for volatile matters, the copper content in the catalyst can be calculated from the amount of raw materials charged.

[0042] <Production of cresol and benzaldehyde> Using the catalyst obtained above, cresol and benzaldehyde were produced from toluene as a raw material. The production of these compounds was carried out using a fixed-bed flow tubular reactor under atmospheric pressure. A Pyrex (registered trademark) glass tube with an inner diameter of 18 mm was used as the reactor.

[0043] After the catalyst was filled in the reactor, the catalyst was heated at 500°C for 2 hours under air flow as a pretreatment. Next, the reactor was purged with nitrogen for 0.5 hours while maintaining the temperature inside the reactor at 500°C. Then, the reaction was carried out by introducing toluene into the reactor using a microfeeder. The product was trapped by cooling to 223K (-50°C) using a mixture of diethylmalonic acid and liquid nitrogen as a refrigerant. The reaction conditions were as follows. (Reaction conditions) W / F=442.5g-cat·min / mol Catalyst amount=1.0g Total flow rate=2.12×10 -3 mol / min N2:O2:Toluene=4:1:0.18=78.4kPa:19.6kPa:3.5kPa Reaction temperature = 400 °C

[0044] Of the obtained products, the liquid phase products were uniformly dissolved in a mixed solvent of 5 μL of toluene as an internal standard and 2 mL of 2-propanol, and analyzed by a high-performance liquid chromatograph (manufactured by JASCO Corporation) using a GH-C18 (reverse-phase distribution type) column, and the gas phase products were analyzed by an online gas chromatograph (manufactured by Shimadzu Corporation) using a ZA-3 (activated carbon support type) column, to determine the yields of p-cresol, o-cresol, and benzaldehyde. The results are shown in Table 1. Here, the yield is the ratio of the number of moles of the product based on the number of moles of the raw material (toluene).

[0045] [Examples 2 to 4] <Catalyst Preparation> The concentration of copper(II) chloride in water is 7.32 x 10 -3 M, 7.50×10 -3 M or 7.66 x 10 -3 Catalysts in which copper was supported on HZSM-5 zeolite were obtained in the same manner as in Example 1, except that the copper content in the catalyst was adjusted to 0.78 mass% (Example 2), 0.91 mass% (Example 3), or 1.04 mass% (Example 4) by adjusting the M.

[0046] <Production of cresol and benzaldehyde> Except for using the catalyst obtained above, cresol and benzaldehyde were produced in the same manner as in Example 1. The yields of each product are shown in Table 1.

[0047] [Examples 5 to 9] <Catalyst Preparation> The concentration of copper(II) chloride in water is 7.50 x 10 -3A catalyst in which copper was supported on HZSM-5 zeolite was obtained in the same manner as in Example 1, except that the copper content in the catalyst was adjusted to 0.90 mass % by adjusting the amount of copper to M.

[0048] <Production of cresol and benzaldehyde> Using the catalyst obtained above, cresol and benzaldehyde were produced in the same manner as in Example 1, except that the reaction conditions, ie, the oxygen partial pressure and the reaction temperature, were changed to those shown in Table 1. The yields of each product are shown in Table 1.

[0049] [Examples 10 to 13] <Catalyst Preparation> A catalyst in which copper was supported on HZSM-5 zeolite was obtained in the same manner as in Example 1, except that the Si / Al atomic ratio of the HZSM-5 zeolite was changed to the value shown in Table 1 by adjusting the amount of NaAlO2 and silica gel charged, and the copper content in the catalyst was adjusted to 0.90 mass% by adjusting the concentration of the copper (II) chloride aqueous solution.

[0050] <Production of cresol and benzaldehyde> Using the catalyst obtained above, cresol and benzaldehyde were produced in the same manner as in Example 1, except that the reaction conditions, ie, the oxygen partial pressure and the reaction temperature, were changed to those shown in Table 1. The yields of each product are shown in Table 1.

[0051] [Comparative Example 1] <Catalyst Preparation> The HZSM-5 zeolite obtained in the same manner as in Example 1 was used as a catalyst without supporting copper.

[0052] <Production of cresol and benzaldehyde> Except for using the catalyst obtained above, cresol and benzaldehyde were produced in the same manner as in Example 1. The yields of each product are shown in Table 1.

[0053] [Comparative Example 2] <Catalyst Preparation> A catalyst was prepared by impregnation of γ-alumina with 0.71 wt% copper.

[0054] <Production of cresol and benzaldehyde> Except for using the catalyst obtained above, cresol and benzaldehyde were produced in the same manner as in Example 1. The yields of each product are shown in Table 1.

[0055] [Table 1]

[0056] As is clear from the results shown in Table 1, it was confirmed that the catalyst of the present invention and the method for producing cresol or benzaldehyde using the catalyst can easily and efficiently produce cresol or benzaldehyde by direct oxidation of toluene. Moreover, it was confirmed that the yield of cresol or benzaldehyde can be improved according to Examples 1 to 13, compared with Comparative Examples 1 and 2.

[0057] From the results of Examples 1 to 4, it was confirmed that the yield of p-cresol varies depending on the amount of supported copper.

[0058] It was confirmed from the results of Examples 5 to 9 that the yield of p-cresol varies depending on the oxygen partial pressure. The amount of benzaldehyde produced increased with an increase in the oxygen partial pressure.

[0059] From the results of Examples 10 to 13, it was confirmed that the yield of p-cresol changes depending on the Si / Al atomic ratio.

Claims

1. The method includes an oxidation step of contacting a catalyst with toluene in the presence of oxygen to oxidize the toluene and produce at least one of cresol and benzaldehyde, The catalyst has a support containing a crystalline aluminosilicate and a supported metal supported on the support, The method for producing cresol or benzaldehyde, wherein the supported metal contains copper.

2. The method according to claim 1, wherein the content of copper in the catalyst is 0.3 to 2.0 mass% based on the total amount of the catalyst.

3. The method according to claim 1, wherein the crystalline aluminosilicate is a pentasil type zeolite.

4. The method according to claim 1, wherein the crystalline aluminosilicate is an MFI type zeolite.

5. The method according to claim 4, wherein the MFI zeolite has a silicon / aluminum atomic ratio of 10 to 100.

6. The method according to claim 1, wherein the oxidation step is carried out in an environment having an oxygen partial pressure of 0.1 to 30.0 kPa.

7. 1. A catalyst for use in oxidizing toluene to produce at least one of cresol and benzaldehyde, comprising: A catalyst comprising a carrier containing a crystalline aluminosilicate and a metal supported on the carrier, A catalyst wherein the supported metal comprises copper.

8. The catalyst according to claim 7, wherein the copper content is 0.3 to 2.0 mass % based on the total amount of the catalyst.

9. 8. The catalyst according to claim 7, wherein the crystalline aluminosilicate is a pentasil type zeolite.

10. 8. The catalyst according to claim 7, wherein the crystalline aluminosilicate is an MFI type zeolite.

11. The catalyst according to claim 10, wherein the silicon / aluminum atomic ratio in the MFI zeolite is 10 to 100.

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