Catalyst for producing alkyl group-containing unsaturated cyclic ether, method for producing alkyl group-containing unsaturated cyclic ether, and method for producing alkyl group-containing saturated cyclic ether

Abstract

A catalyst for producing an alkyl-group-containing unsaturated cyclic ether, the catalyst being used for producing an alkyl-group-containing unsaturated cyclic ether (2) from an unsaturated cyclic ether (1) that has a formyl group or a hydroxymethyl group, and the catalyst containing ruthenium and at least either one of tin or platinum. A method for producing an alkyl-group-containing unsaturated cyclic ether, the method including a reaction step for carrying out a hydrogenation and deoxygenation reaction, in the presence of the aforementioned catalyst, on an unsaturated cyclic ether (1) that has a formyl group or a hydroxymethyl group to obtain an alkyl-group-containing unsaturated cyclic ether (2).

Description

[Technical Field]

[0001] The present invention relates to a catalyst for producing alkyl group-containing cyclic ethers, a method for producing alkyl group-containing cyclic ethers, and a method for producing alkyl group-containing saturated cyclic ethers. [Background technology]

[0002] Alkyl-containing saturated cyclic ethers (hereinafter referred to as "alkyl-containing saturated cyclic ethers"), especially 2-methyltetrahydrofuran (2MeTHF), are important organic intermediates and excellent solvents. The boiling points of alkyl-containing saturated cyclic ethers are moderate (80°C). They have low solubility in water, readily separate from water, and possess Lewis basicity similar to that of tetrahydrofuran (THF). Therefore, alkyl-containing saturated cyclic ethers are applicable to many organometallic reactions and are currently widely used industrially as new solvents and raw materials for pharmaceuticals. Furthermore, alkyl-containing saturated cyclic ethers, especially 2-methyltetrahydrofuran, have excellent compatibility with hydrocarbon compositions such as gasoline. Alkyl-containing saturated cyclic ethers have excellent oxidation and vapor pressure properties. For this reason, they are used as additives for gasoline and other mobile fuels.

[0003] As a starting material for the industrial production of alkyl group-containing saturated cyclic ethers, such as 2-MeTHF, unsaturated cyclic ethers having a formyl group or a hydroxymethyl group, such as furfural, which correspond to the cyclic ethers (hereinafter referred to as "formyl group- or hydroxymethyl group-containing unsaturated cyclic ethers"), are used.

[0004] Currently, 2-MeTHF is produced from furfural via a two-step catalytic hydrogenation process.

[0005] For example, Patent Document 1 discloses a technology in which furfural is hydrogenated by a continuous gas-phase reaction in the presence of a copper catalyst to produce 2-methylfuran (2MeF), an unsaturated cyclic ether containing an alkyl group (hereinafter referred to as "alkyl-containing unsaturated cyclic ether"), and the resulting 2MeF is subjected to a high-pressure catalytic hydrogenation reaction in the presence of a Pd / C catalyst to produce 2-MeTHF.

[0006] Patent Document 2 discloses a technique for producing 2-MeTHF by hydrogenating furfural through a continuous gas phase reaction in the presence of a Pd / C catalyst. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Special Publication No. 2010-531838 [Patent Document 2] Special Publication No. 2010-531839 Summary of the Invention [Problem to be solved by the invention]

[0008] In the techniques described in Patent Documents 1 and 2, the conversion rate of the raw material furfural was low in the first-stage reaction, and the amount of by-products such as 1-pentanol and 1,2-pentanediol produced by the ring-opening reaction of the furan ring in the raw material furfural was large, resulting in an insufficient yield of 2-methylfuran. In the technologies described in Patent Documents 1 and 2, gaseous furfural and hydrogen gas are used as raw materials in the first-stage reaction, so measures to prevent explosion of the gas must be considered, which requires additional costs. In addition, excessively large high-pressure gas equipment is required, which increases production costs. Furthermore, because a continuous gas-phase reaction technology is used, there is also the problem that the processing speed of the raw materials is very slow.

[0009] The present invention has been made in view of the above problems of the prior art. An object of the present invention is to provide a catalyst for producing an alkyl group-containing unsaturated cyclic ether, such as 2-methylfuran, which can be used to carry out a reaction in a liquid phase when producing an alkyl group-containing unsaturated cyclic ether, such as 2-methylfuran, using a formyl group- or hydroxymethyl group-containing cyclic ether, such as furfural, as a starting material, and which can produce an alkyl group-containing unsaturated cyclic ether, such as 2-methylfuran, in high yield with fewer by-products than conventional techniques. Another object of the present invention is to provide a method for producing an alkyl group-containing unsaturated cyclic ether, such as 2-methylfuran, from a formyl group- or hydroxymethyl group-containing unsaturated cyclic ether, such as furfural, using the catalyst for producing an alkyl group-containing unsaturated cyclic ether. Another object of the present invention is to provide a method for producing an alkyl group-containing saturated cyclic ether, which uses an alkyl group-containing unsaturated cyclic ether such as 2-methylfuran obtained by the method for producing an alkyl group-containing unsaturated cyclic ether, such as 2-methyltetrahydrofuran, corresponding to the alkyl group-containing unsaturated cyclic ether. [Means for solving the problem]

[0010] The present inventors have found that the above-mentioned problems can be solved by using a catalyst containing ruthenium and at least either tin or platinum as a catalyst for producing an alkyl group-containing unsaturated cyclic ether such as 2-methylfuran from a formyl group- or hydroxymethyl group-containing unsaturated cyclic ether such as furfural. The present invention was achieved based on these findings and has the following gist.

[0011] [1] A catalyst for producing an alkyl group-containing unsaturated cyclic ether (2) from an unsaturated cyclic ether (1) having a formyl group or a hydroxymethyl group, comprising: A catalyst for producing an alkyl group-containing unsaturated cyclic ether, which contains ruthenium and at least one of tin and platinum.

[0012] [2] The catalyst for producing an alkyl group-containing unsaturated cyclic ether according to [1], wherein the mass ratio of tin and platinum to ruthenium is 0.4 or more and 1.8 or less.

[0013] [3] The catalyst for producing an alkyl group-containing unsaturated cyclic ether according to [1] or [2], wherein the catalyst is a metal-supported material comprising ruthenium and at least one of tin and platinum supported on a carrier.

[0014] [4] The catalyst for producing an alkyl group-containing unsaturated cyclic ether according to [3], wherein the support is a carbonaceous support.

[0015] [5] The catalyst for producing an alkyl group-containing unsaturated cyclic ether according to any one of [1] to [4], wherein the unsaturated cyclic ether (1) is furfural and the unsaturated cyclic ether (2) is 2-methylfuran.

[0016] [6] A method for producing an alkyl group-containing unsaturated cyclic ether, comprising a reaction step of subjecting an unsaturated cyclic ether (1) having a formyl group or a hydroxymethyl group to a hydrodeoxygenation reaction in the presence of the catalyst according to any one of [1] to [5] to obtain an alkyl group-containing unsaturated cyclic ether (2).

[0017] [7] The method for producing an alkyl group-containing unsaturated cyclic ether according to [6], wherein the hydrodeoxygenation reaction is a liquid phase reaction in the presence of an organic solvent.

[0018] [8] The method for producing an alkyl group-containing unsaturated cyclic ether according to [7], wherein the organic solvent is at least one selected from the group consisting of ether compounds, alcohol compounds, and ester compounds.

[0019] [9] The method for producing an alkyl group-containing unsaturated cyclic ether according to any one of [6] to [8], wherein the reaction temperature of the hydrodeoxygenation reaction is 185° C. or higher.

[0020]

[10] A method for producing an alkyl group-containing saturated cyclic ether, comprising: a hydrodeoxygenation step of obtaining an alkyl group-containing unsaturated cyclic ether by the method for producing an alkyl group-containing unsaturated cyclic ether according to any one of [6] to [9]; and a hydrogenation step of hydrogenating the obtained alkyl group-containing unsaturated cyclic ether in the presence of a noble metal catalyst containing at least one noble metal selected from the group 8 noble metals and the group 10 noble metals of the periodic table of the elements, to obtain an alkyl group-containing saturated cyclic ether.

[0021]

[11] A method for producing an alkyl group-containing saturated cyclic ether, comprising: obtaining an alkyl group-containing unsaturated cyclic ether by the method for producing an alkyl group-containing unsaturated cyclic ether according to any one of [6] to [9]; and adding a noble metal catalyst containing at least one selected from the group consisting of noble metals belonging to Group 8 and Group 10 of the Periodic Table of the Elements to the obtained alkyl group-containing unsaturated cyclic ether, and subjecting the noble metal to a hydrogenation reaction to obtain an alkyl group-containing saturated cyclic ether. [Effects of the Invention]

[0022] According to the present invention, it is possible to provide a catalyst for producing an alkyl group-containing unsaturated cyclic ether, which can carry out a reaction in a liquid phase and produce an alkyl group-containing unsaturated cyclic ether such as 2-methylfuran from a formyl group- or hydroxymethyl group-containing unsaturated cyclic ether such as furfural in high yield with fewer by-products than those produced by conventional techniques.

[0023] The catalyst for producing alkyl group-containing unsaturated cyclic ethers of the present invention allows the reaction to be carried out in a liquid phase, and therefore does not require the above-mentioned excessively large high-pressure gas equipment, compared to conventional methods using gaseous raw materials, thereby reducing production costs. Furthermore, when furfural is used as the formyl group- or hydroxymethyl group-containing unsaturated cyclic ether, the catalyst for producing alkyl group-containing unsaturated cyclic ethers of the present invention can suppress the by-production of 1-pentanol or 1,2-pentanediol due to the ring-opening reaction of the furan ring, compared to conventional copper-based catalysts, and can produce alkyl group-containing unsaturated cyclic ethers such as 2-methylfuran in higher yields.

[0024] Furthermore, according to the present invention, an alkyl group-containing saturated cyclic ether such as 2-methyltetrahydrofuran can be efficiently produced from an alkyl group-containing unsaturated cyclic ether such as 2-methylfuran produced by the method for producing an alkyl group-containing unsaturated cyclic ether of the present invention using the catalyst for producing an alkyl group-containing unsaturated cyclic ether. DETAILED DESCRIPTION OF THE INVENTION

[0025] The present invention will be described in detail below with reference to the preferred embodiments. The present invention is not limited to the following description, and can be modified in any manner without departing from the spirit and scope of the present invention.

[0026] In this specification, unless otherwise specified, a numerical range expressed using "to" means a range that includes the numerical values ​​written before and after "to" as the lower and upper limits, and "A to B" means A or more and B or less.

[0027] In this specification, "A or B" means "A," "B," and "A and B," unless otherwise specified. For example, "including A or B" means "including A," "including B," and "including A and B," unless otherwise specified.

[0028] In this specification, "% by mass" indicates the content of a given component in a total amount of 100% by mass. In this specification, "mass %" and "weight %", "mass ppm" and "weight ppm", and "parts by mass" and "parts by weight" have the same meaning. When simply written as "ppm", it means "ppm by mass".

[0029] "Optional" or "optionally" means that the subsequently described circumstance may or may not occur, and thus the description includes both the occurrence and non-occurrence of the circumstance.

[0030] As used herein, the term "about" means above and below 20% of the stated value. For example, about 75°C encompasses the range of 60°C to 90°C.

[0031] All steps described herein can be performed in any suitable order unless otherwise stated herein or clearly contradicted by context.

[0032] [Catalyst for producing alkyl group-containing unsaturated cyclic ethers] The catalyst for producing an alkyl group-containing unsaturated cyclic ether of the present invention (hereinafter sometimes referred to as "the catalyst") is a catalyst used for producing an alkyl group-containing unsaturated cyclic ether (2). More specifically, the catalyst is used in a process for producing an alkyl group-containing, particularly methyl group-containing, unsaturated cyclic ether (2) corresponding to the unsaturated cyclic ether (1) from a formyl group- or hydroxymethyl group-containing unsaturated cyclic ether (1), and contains ruthenium and at least either tin or platinum (hereinafter sometimes abbreviated as "Ru / Sn·Pt").

[0033] In this specification, when the phrase "at least one of tin and platinum" is used, either one of tin and platinum may be used, or both tin and platinum may be used. Among these, the use of both tin and platinum in combination with ruthenium is preferred from the viewpoint of the yield of the target product.

[0034] Because this catalyst contains Ru / Sn·Pt, it is suitable as a catalyst for use in the production of alkyl group-containing unsaturated cyclic ether (2). Specifically, by using this catalyst as a catalyst for producing alkyl group-containing unsaturated cyclic ether (2), which corresponds to unsaturated cyclic ether (1), from formyl group- or hydroxymethyl group-containing unsaturated cyclic ether (1), the unsaturated cyclic ether (2) can be produced in high yield with few by-products.

[0035] This catalyst is usually used as a metal-supported catalyst, in which the aforementioned Ru / Sn·Pt is supported on a carrier. This catalyst is usually produced by reducing the metal-supported material, in which Ru / Sn·Pt is supported on a carrier, with a reducing gas, followed by an oxidation stabilization treatment.

[0036] <Catalytic active component> The catalytically active component in the present catalyst contains ruthenium and at least either tin or platinum (Ru / Sn·Pt). The mass ratio of tin and platinum to ruthenium in the catalyst (when the catalyst contains either tin or platinum, the mass ratio of either tin or platinum; when the catalyst contains both tin and platinum, the total mass ratio) is not particularly limited. From the viewpoint of producing the unsaturated cyclic ether (2) in high yield with few by-products, this mass ratio is preferably 0.4 to 1.8, more preferably 0.45 to 1.5, and even more preferably 0.5 to 1.2. If this mass ratio is within the above range, the effects of the present invention can be effectively obtained by using ruthenium in combination with at least one of tin and platinum.

[0037] <Other metal components> The present catalyst may contain Ru / Sn·Pt as an essential component, and may further contain other metals in addition to Ru / Sn·Pt, as necessary, as long as the effects of the present invention are not impaired. The other metals are not particularly limited. The other metals are preferably at least one selected from metal species such as rhodium, gold, molybdenum, tungsten, rhenium, barium, and boron, and more preferably at least one selected from rhenium and gold. However, this catalyst can achieve sufficiently high catalytic activity by using Ru / Sn·Pt.

[0038] When the catalyst contains other metal components, the lower limit of the content of the other metal components relative to 100% by total mass of Ru / Sn·Pt and the other metal components is not particularly limited, but from the viewpoint of producing the unsaturated cyclic ether (2) in high yield with few by-products, it is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and preferably 1.0% by mass or more. On the other hand, the upper limit of the content of the other metal components is not particularly limited, but is preferably 10% by mass or less, more preferably 5% by mass or less, and preferably 3% by mass or less. The above upper and lower limits can be combined in any way.

[0039] <Carrier> This catalyst can be used as a Ru / Sn·Pt supported catalyst, in which Ru / Sn·Pt is supported on a support. The Ru / Sn·Pt supported catalyst is easy to handle and exhibits catalytic function not only on the surface of the Ru / Sn·Pt supported catalyst but also inside the pores where the Ru / Sn·Pt is supported. This is therefore preferable from the viewpoint of improving the conversion rate of the raw material unsaturated cyclic ether (1) and the selectivity of the target product unsaturated cyclic ether (2).

[0040] The type of support used in the present catalyst is not particularly limited. Examples of the support include carbonaceous supports such as activated carbon and carbon black; silica, diatomaceous earth; inorganic porous supports of oxide ceramics such as silicon oxide, alumina, zirconia, titania, and hafnia; silicon carbide; and gallium nitride. Among these, carbonaceous supports are preferred, and activated carbon is more preferred.

[0041] The support may be used as is or may be pretreated to a form suitable for loading. For example, when a carbonaceous support is used, the carbonaceous support may be heat-treated with nitric acid as described in JP-A-10-71332. This method is preferred because it improves the dispersibility of the metal components on the support and improves the activity of the resulting catalyst.

[0042] The shape of the carrier used in this catalyst is not particularly limited, and examples include powder, particle, pellet, and the like. Among these, from the perspective of improving operability, granular and pellet shapes are preferred. The size of the carrier used in this catalyst is not particularly limited, but when its shape is converted to a spherical shape, the average particle diameter is usually 50 μm or more and 5 mm or less, preferably 4 mm or less. The particle diameter of the carrier is measured by the sieving test method described in JIS standard JIS Z8815 (1994). By setting the average particle diameter within the above range, a catalyst with high activity per unit weight and easier handling can be obtained.

[0043] When the reaction using this catalyst is a complete mixing type reaction, the particle diameter of the carrier is usually 50 μm or more, preferably 100 μm or more, usually 3 mm or less, preferably 2 mm or less. A smaller particle diameter of the carrier is preferable in that the activity per unit mass of the obtained catalyst is higher. If the particle diameter of the carrier becomes too small compared to the lower limit value, it may be difficult to separate the reaction solution and the catalyst. When the shape of the carrier is not spherical, the particle diameter of the carrier is obtained by calculating the volume of the carrier and converting it to the diameter of spherical particles with the same volume.

[0044] When the reaction using this catalyst is a fixed bed reaction, the particle diameter of the carrier is usually 0.5 mm or more and 5 mm or less, preferably 4 mm or less, more preferably 3 mm or less. If the particle diameter is too small compared to the lower limit value, the operation may be difficult due to differential pressure. If the particle diameter is too large compared to the upper limit value, the reaction activity may decrease.

[0045] <Supported amount of Ru / Sn·Pt> The supported amount of Ru / Sn·Pt on the carrier in this catalyst is not particularly limited. For example, the lower limit of the supported amount of ruthenium is usually 1 part by mass or more, preferably 3 parts by mass or more, based on 100 parts by mass of the total mass of this catalyst. On the other hand, the upper limit of the supported amount of Ru / Sn·Pt is usually 10 parts by mass or less, preferably 8 parts by mass or less, based on 100 parts by mass of the total mass of this catalyst. The above upper and lower limits can be combined in any desired manner. For example, the amount of Ru / Sn·Pt supported on the carrier in the present catalyst is usually 1 part by mass or more and 10 parts by mass or less, and preferably 3 parts by mass or more and 8 parts by mass or less, per 100 parts by mass of the total mass of the present catalyst.

[0046] The lower limit of the amount of either or both of tin and platinum supported on the carrier in the present catalyst is usually 1 part by mass or more, preferably 2 parts by mass or more, per 100 parts by mass of the total mass of the present catalyst, while the upper limit of the amount of either or both of tin and platinum supported is usually 15 parts by mass or less, preferably 10 parts by mass or less, per 100 parts by mass of the total mass of the present catalyst. The above upper and lower limits can be combined in any manner. For example, the amount of tin and / or platinum supported on the carrier in the present catalyst is usually 1 part by mass or more and 15 parts by mass or less, and preferably 2 parts by mass or more and 10 parts by mass or less, per 100 parts by mass of the total mass of the present catalyst.

[0047] The amount of other metals to be supported, if necessary, is not particularly limited, and is usually 7 parts by mass or less, preferably 5 parts by mass or less, per 100 parts by mass of the total mass of the catalyst, as long as the effects of the present invention are not impaired.

[0048] The lower limit of the total amount of Ru / Sn·Pt and other metals supported is not particularly limited, but is usually 5 parts by mass or more, preferably 8 parts by mass or more, and more preferably 10 parts by mass or more, relative to 100 parts by mass of the total mass of the catalyst. On the other hand, the upper limit of the total amount of Ru / Sn·Pt and other metals supported is not particularly limited, but is usually 40 parts by mass or less, preferably 30 parts by mass or less, and more preferably 20 parts by mass or less, relative to 100 parts by mass of the total mass of the catalyst. The above upper and lower limits can be combined in any desired manner. For example, the total amount of Ru / Sn·Pt and other metals supported is usually 5 to 40 parts by mass, preferably 8 to 30 parts by mass, and more preferably 10 to 20 parts by mass, per 100 parts by mass of the total mass of the catalyst.

[0049] The amount of supported metal is a value calculated assuming that all the supported metal is metal atom. The amount of supported metal can be measured, for example, by eluting the metal component from the metal-supported catalyst with an acid and analyzing the concentration in the solution by atomic absorption spectrometry or inductively coupled plasma (ICP) emission spectrometry, or by crushing the metal-supported catalyst to 50 μm or less and then subjecting it to solid-state X-ray fluorescence (XRF) analysis.

[0050] <Method of manufacturing the catalyst> There are no particular limitations on the method for producing the catalyst. The catalyst can be produced by optimizing, for example, the catalyst production method described in paragraphs 0033 to 0079 of JP 2020-168628 A according to well-known techniques.

[0051] [Formyl or hydroxymethyl group-containing unsaturated cyclic ether (1)] The formyl- or hydroxymethyl-containing unsaturated cyclic ether (1) to which the present catalyst is applied is not particularly limited, but examples thereof include 5- or 6-membered unsaturated cyclic ethers having a formyl or hydroxymethyl group, such as furan, pyran, and dihydropyran. Among these, from the viewpoints of the application and availability of the alkyl-containing unsaturated cyclic ether (2) produced by the present catalyst, furfural and dihydropyran are preferred, with furfural being the most preferred.

[0052] [Alkyl-containing unsaturated cyclic ether (2)] The alkyl group-containing unsaturated cyclic ether (2) produced from the formyl group- or hydroxymethyl group-containing unsaturated cyclic ether (1) using this catalyst is a product in which the formyl group or hydroxymethyl group is converted to a methyl group by hydrodeoxygenation of the formyl group- or hydroxymethyl group-containing unsaturated cyclic ether (1). Specific examples include 2-methylfuran and 2-methyl-2,3-dihydro-4H-pyran. For the same reasons as above, 2-methylfuran is most preferred.

[0053] The present catalyst is suitable as a catalyst for producing 2-methylfuran as an alkyl group-containing unsaturated cyclic ether (2) from furfural as a formyl group- or hydroxymethyl group-containing unsaturated cyclic ether (1).

[0054] [Method of producing alkyl group-containing unsaturated cyclic ether] The method for producing an alkyl group-containing unsaturated cyclic ether of the present invention is a method for producing an alkyl group-containing unsaturated cyclic ether (2), comprising a reaction step of subjecting a formyl group- or hydroxymethyl group-containing unsaturated cyclic ether (1) to a hydrodeoxygenation reaction in the presence of the present catalyst to obtain an alkyl group-containing unsaturated cyclic ether (2) corresponding to the formyl group- or hydroxymethyl group-containing unsaturated cyclic ether (1).

[0055] The method for producing alkyl group-containing unsaturated cyclic ether (2) using the present catalyst is not particularly limited as long as it proceeds in the presence of the present catalyst. The method for producing alkyl group-containing unsaturated cyclic ether (2) using the present catalyst is preferably a heterogeneous reaction in which formyl group- or hydroxymethyl group-containing unsaturated cyclic ether (1), the present catalyst, and hydrogen are contacted continuously or batchwise to carry out a hydrodeoxygenation reaction.

[0056] More specifically, the hydrodeoxygenation reaction may be a gas-liquid-solid three-phase reaction carried out by contacting a liquid formyl- or hydroxymethyl-containing unsaturated cyclic ether (1) or a solution containing the formyl- or hydroxymethyl-containing unsaturated cyclic ether (1) with hydrogen (hydrogen gas), or a gas-solid two-phase reaction carried out by reacting the gaseous (vaporized) formyl- or hydroxymethyl-containing unsaturated cyclic ether (1) with hydrogen. In particular, from the viewpoint of suppressing the production of by-products due to cleavage of carbon-carbon bonds in the formyl- or hydroxymethyl-containing unsaturated cyclic ether (1), it is preferable to carry out the hydrodeoxygenation reaction in a gas-liquid-solid three-phase system, which can be carried out at a relatively low temperature. In particular, a liquid-phase reaction is preferably carried out by contacting a solution containing the formyl- or hydroxymethyl-containing unsaturated cyclic ether (1) with hydrogen in the presence of the catalyst.

[0057] The solvent used in the liquid phase reaction can be appropriately selected depending on the type of formyl or hydroxymethyl group-containing unsaturated cyclic ether (1) without any particular limitation. When water is used as the solvent, polymerization and rearrangement reactions tend to proceed, but the hydrodeoxygenation reaction does not proceed. Therefore, it is preferable to use an organic solvent.

[0058] The organic solvent used in the hydrodeoxygenation reaction of the present invention is not particularly limited, but examples thereof include the following: Ether compounds such as dioxane and 2-methyltetrahydrofuran; ester compounds such as ethyl acetate and butyl acetate; Alcoholic compounds such as methanol, ethanol, isopropanol, n-butanol, and 2-butanol; Aliphatic hydrocarbon compounds such as hexane, heptane, and octane; Alicyclic hydrocarbon compounds such as cyclohexane; Aromatic hydrocarbon compounds such as benzene, toluene, xylene, and ethylbenzene; Halogenated hydrocarbon compounds such as chloroform, methylene chloride, and 1,2-dichloroethane; Nitrile compounds such as acetonitrile, propionitrile, and benzonitrile. These organic solvents can be used alone or in combination of two or more.

[0059] Among these organic solvents, ether compounds, alcohol compounds and ester compounds are preferred from the viewpoints of ease of separation from the product, economy and toxicity, and ether compounds and alcohol compounds are particularly preferred.

[0060] The amount of the organic solvent used is not particularly limited and can be appropriately selected from a range such that the concentration of the formyl- or hydroxymethyl-containing unsaturated cyclic ether (1) dissolved before the hydrodeoxygenation reaction is 5 to 80 mass%, particularly 20 to 60 mass%.

[0061] The lower limit of the amount of the catalyst used in the hydrodeoxygenation reaction is not particularly limited, but from the viewpoint of reaction rate, it is preferably 2% by mass or more, more preferably 5% by mass or more, and even more preferably 8% by mass or more, calculated as Ru / Sn·Pt metals relative to the formyl- or hydroxymethyl-containing unsaturated cyclic ether (1). On the other hand, the upper limit of the amount of the catalyst used is not particularly limited, but from the viewpoint of economy, it is preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 18% by mass or less, calculated as Ru / Sn·Pt metals relative to the formyl- or hydroxymethyl-containing unsaturated cyclic ether (1). The above upper and lower limits can be combined in any manner. For example, the amount of the catalyst used in the hydrodeoxygenation reaction is preferably 2 to 25 mass %, more preferably 5 to 20 mass %, and even more preferably 8 to 18 mass %, calculated as the metal amount of Ru / Sn·Pt relative to the formyl group- or hydroxymethyl group-containing unsaturated cyclic ether (1).

[0062] The ratio of hydrogen to the formyl- or hydroxymethyl-containing unsaturated cyclic ether (1) used in the hydrodeoxygenation reaction is not particularly limited and can be appropriately determined depending on the reaction type employed.

[0063] In the hydrodeoxygenation reaction, components other than the formyl- or hydroxymethyl-containing unsaturated cyclic ether (1), the present catalyst, and hydrogen may also be present within the scope of not impairing the effects of the present invention.

[0064] The lower limit of the reaction temperature in the hydrodeoxygenation reaction is not particularly limited, but if the reaction temperature is too low, the hydrodeoxygenation reaction will not proceed smoothly. Therefore, the reaction temperature is preferably 185°C or higher, more preferably 190°C or higher, and even more preferably 200°C or higher. On the other hand, the upper limit of the reaction temperature is not particularly limited, but if it is too high, side reactions will tend to proceed. Therefore, the upper limit is preferably 240°C or lower, more preferably 230°C or lower, and even more preferably 220°C or lower. The above upper and lower limits can be combined in any desired manner. For example, the reaction temperature in the hydrodeoxygenation reaction is not particularly limited, but is preferably 185°C or higher and 240°C or lower, more preferably 190°C or higher and 230°C or lower, and even more preferably 200°C or higher and 220°C or lower. The reaction temperature may be controlled so as to be always constant (substantially constant) during the hydrodeoxygenation reaction, or may be controlled so as to change stepwise or continuously.

[0065] The reaction time for the hydrodeoxygenation reaction is not particularly limited and can be appropriately set depending on the reaction type to be adopted.

[0066] The lower limit of the reaction pressure in the hydrodeoxygenation reaction (hydrogen gas pressure in the hydrodeoxygenation reaction) is not particularly limited, but is usually 0.1 MPa or more, more preferably 1.0 MPa or more. On the other hand, the upper limit of the reaction pressure is not particularly limited, but is usually 20 MPa or less, more preferably 10 MPa or less. The above upper and lower limits can be combined in any desired manner. For example, the reaction pressure in the hydrodeoxygenation reaction is not particularly limited, but is usually 0.1 to 20 MPa, and more preferably 1 to 10 MPa. The reaction pressure may be controlled so as to be always constant (substantially constant) during the hydrodeoxygenation reaction, or may be controlled so as to change stepwise or continuously.

[0067] The hydrodeoxygenation reaction can be carried out in any manner, such as a batch system, a semi-batch system, or a continuous system (continuous flow system).

[0068] When it is desired to increase the amount of alkyl group-containing unsaturated cyclic ether (2) obtained from a given amount of formyl group- or hydroxymethyl group-containing unsaturated cyclic ether (1), a process may be employed in which the unreacted formyl group- or hydroxymethyl group-containing unsaturated cyclic ether (1) after the reduction reaction is carried out is separated, recovered, and recycled.

[0069] In the hydrodeoxygenation reaction, a known or conventional reactor can be used as the reactor, such as a batch reactor, a fluidized bed reactor, or a fixed bed reactor.

[0070] The method for producing an alkyl group-containing unsaturated cyclic ether of the present invention may optionally include other steps in addition to the hydrodeoxygenation reaction, as necessary, such as a step of preparing and purifying a solution of the starting material, formyl group- or hydroxymethyl group-containing unsaturated cyclic ether (1), a step of separating and purifying the reaction product discharged (outflowed) from the reactor (e.g., a mixture containing alkyl group-containing unsaturated cyclic ether (2), hydrogen, and formyl group- or hydroxymethyl group-containing unsaturated cyclic ether (1), by-products, etc.), and a step of regenerating the catalyst. These steps may be carried out in a line separate from the hydrodeoxygenation reaction, or may be carried out as a series of steps (in-line).

[0071] The alkyl group-containing unsaturated cyclic ether (2) obtained by the method for producing an alkyl group-containing unsaturated cyclic ether of the present invention can be purified by known or conventional methods (e.g., distillation, adsorption, ion exchange, crystallization, extraction, etc.).

[0072] The following methods can be used to recover the target substance.

[0073] The reaction product obtained in the hydrodeoxygenation reaction step is condensed by a known technique, preferably by cooling in a heat exchanger. Condensation causes phase separation. The lower phase obtained by phase separation consists of more than 90% water. The upper phase obtained by phase separation contains the desired alkyl group-containing unsaturated cyclic ether (2) and a small amount of by-products, which can be efficiently separated and removed by subsequent distillation or other separation steps. The alkyl group-containing unsaturated cyclic ether (2) can be obtained in very good yield and purity by the method of the present invention.

[0074] Phase separation can be carried out at room temperature (about 25°C), but since the alkyl group-containing unsaturated cyclic ether (2) has a lower solubility in water at lower temperatures, it is preferable to carry out phase separation at 20°C or below, for example, 5 to 15°C.

[0075] The upper phase containing the alkyl group-containing unsaturated cyclic ether (2), which is the target product obtained by phase separation, can be distilled using, for example, a packed column containing packings such as metal rings, to recover high-purity alkyl group-containing unsaturated cyclic ether (2). However, this distillation step is not necessarily required. For example, when the resulting alkyl group-containing unsaturated cyclic ether (2) is hydrogenated by the method for producing an alkyl group-containing saturated cyclic ether of the present invention described below, the reaction product liquid obtained in the hydrodeoxygenation reaction may be directly supplied to the subsequent hydrogenation reaction step.

[0076] [Method of producing alkyl group-containing saturated cyclic ether] A first embodiment of the method for producing an alkyl group-containing saturated cyclic ether of the present invention includes a step of obtaining an alkyl group-containing unsaturated cyclic ether (2) by the method for producing an alkyl group-containing unsaturated cyclic ether of the present invention, and a hydrogenation step of hydrogenating the obtained alkyl group-containing unsaturated cyclic ether (2) in the presence of a noble metal catalyst containing at least one noble metal selected from Group 8 noble metals and Group 10 noble metals of the Periodic Table of the Elements to obtain an alkyl group-containing saturated cyclic ether (hereinafter sometimes referred to as "alkyl group-containing saturated cyclic ether (3)") corresponding to the alkyl group-containing unsaturated cyclic ether (2).

[0077] A second embodiment of the method for producing an alkyl group-containing saturated cyclic ether of the present invention includes obtaining an alkyl group-containing unsaturated cyclic ether by the method for producing an alkyl group-containing unsaturated cyclic ether of the present invention, and adding a catalyst containing at least one selected from Group 8 noble metals and Group 10 noble metals of the Periodic Table of the Elements to the obtained alkyl group-containing unsaturated cyclic ether to perform a hydrogenation reaction, thereby obtaining an alkyl group-containing saturated cyclic ether (3).

[0078] <Precious metal catalyst> In the first and second embodiments of the method for producing an alkyl group-containing saturated cyclic ether of the present invention, the noble metal of the noble metal catalyst containing at least one selected from the noble metals of Group 8 and Group 10 of the Periodic Table of the Elements used in the hydrogenation reaction is preferably rhodium, ruthenium, platinum, palladium, iridium, osmium, etc. Among these, ruthenium, rhodium, and palladium are particularly preferred from the viewpoints of reactivity and selectivity.

[0079] Specific examples of the noble metal catalyst include metal compounds such as zero-valent noble metals, or various inorganic compounds such as noble metal nitrates, sulfates, acetates, chlorides, bromides, oxides, and hydroxides; carrier-supported catalysts in which noble metals are supported on a carrier; various organic compounds such as acetylacetonate compounds; and various complex compounds such as amine complexes, phosphine complexes, and carbonyl compounds. These may be used alone or in combination of two or more.

[0080] The amount of metal component supported on the carrier-supported catalyst is not particularly limited, but is usually 0.1 to 10 mass%, preferably 0.5 to 5 mass%, in terms of metal content relative to the total mass of the catalyst. If the amount supported is less than 0.1 mass%, the activity per catalyst amount decreases, and a large amount of catalyst must be used, which is disadvantageous both in terms of equipment and economy. If the amount supported exceeds 10 mass%, it is difficult to obtain an improvement in reaction rate commensurate with the amount of metal supported.

[0081] As the carrier-supported catalyst, conventionally known or commercially available catalysts can be used. Examples of supports used in the support-supported catalyst include diatomaceous earth, pumice, carbon (activated carbon, graphite, carbon black, etc.), silica gel, alumina, silica-alumina, magnesium oxide, zirconium oxide, titanium oxide, zeolite, calcium carbonate, and barium sulfate. These supports can be used alone or in combination of two or more. Of these, carbon or alumina is particularly preferred in terms of reactivity and selectivity.

[0082] Specific examples of the noble metal supported catalyst include Ru-carbon catalyst, Rh-carbon catalyst, Pd-carbon catalyst, Ru-alumina catalyst, Rh-alumina catalyst, and Pd-alumina catalyst. Among these, Pd-carbon catalyst and Pd-alumina catalyst are particularly preferred.

[0083] The water content of the noble metal-supported catalyst is not particularly limited, and either a dry product or a wet product can be used.

[0084] The form of the noble metal catalyst in the present invention is not particularly limited, and may be in the form of a powder, molded catalyst, or the like, which is appropriately selected depending on the reaction method selected. Powdered catalysts are typically used in batch or continuous liquid phase slurry bed hydrogenation reactions. The molded catalyst is used in the hydrogenation reaction of a fixed bed flow system. The molded catalyst is appropriately selected depending on the size of the reactor to be used. The molded catalyst is preferably cylindrical, usually with a diameter of 2 to 6 mm and a height of 2 to 8 mm.

[0085] The supported catalyst can be prepared by a conventional method such as impregnation, coprecipitation, etc. The method for activating the supported catalyst is not particularly limited, but the catalyst is usually activated by reduction before use.

[0086] The amount of the noble metal catalyst used in the hydrogenation reaction is preferably 0.0005 to 5 parts by mass, preferably 0.005 to 3 parts by mass, and more preferably 0.01 to 2 parts by mass, based on the metal content, per 100 parts by mass of the total mass of the alkyl group-containing unsaturated cyclic ether (2), from the viewpoints of reaction rate and economy.

[0087] <Reaction solvent> The hydrogenation reaction according to the present invention can be carried out either without a solvent or in the presence of a solvent. When the reaction is carried out in the presence of a solvent, the solvent that can be used is not particularly limited as long as it does not adversely affect the hydrogenation reaction.

[0088] Examples of the reaction solvent include: water; known alcohol solvents such as methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, hexanol, heptanol, octanol, propylene glycol, ethylene glycol, diethylene glycol, tetraethylene glycol, glycerin, 1,3-propanediol, and cyclohexanol; known ether solvents such as diethyl ether, diisopropyl ether, dibutyl ether, ethylene glycol dimethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, 1,3-dioxane, and 1,4-dioxane; known aliphatic hydrocarbon solvents such as n-pentane, n-hexane, n-heptane, n-octane, 2-ethylhexane, n-nonane, n-decane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, and decalin; known ester solvents such as methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, hexyl acetate, methyl propionate, and ethyl propionate; known carbonate ester solvents such as ethylene carbonate, propylene carbonate, dimethyl carbonate, and diethyl carbonate; Lactone solvents such as γ-butyrolactone, γ-valerolactone, δ-valerolactone, and ε-caprolactone; Amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone etc. These solvents can be used alone or in combination of two or more.

[0089] The amount of the reaction solvent used can be selected arbitrarily depending on the reaction conditions, reaction form, and the like.

[0090] <Reaction conditions> The hydrogen partial pressure in the hydrogenation reaction according to the present invention is not particularly limited as long as it is a condition that allows the hydrogenation reaction to be completed. To obtain a practical reaction rate, the hydrogen partial pressure in the reaction system is usually in the range of 0.1 to 30 MPa, preferably 0.1 to 10 MPa. If the hydrogen partial pressure is lower than 0.1 MPa, the reaction will take longer than necessary. If the hydrogen partial pressure exceeds 30 MPa, the reaction rate will increase, but if the pressure is too high, no significant benefits will be observed and it may be economically disadvantageous.

[0091] The reaction temperature is not particularly limited as long as it is a condition under which the hydrogenation reaction can be completed. The reaction temperature under conditions under which a practical reaction rate can be obtained is usually 20 to 200°C, preferably 40 to 180°C. If the temperature is lower than this range, a sufficient reaction rate cannot be obtained. If the temperature is higher than this range, side reactions and decomposition reactions occur, and the yield tends to decrease.

[0092] The reaction time varies depending on the amount of catalyst and other conditions, but it is generally about 0.5 to 50 hours, and from an industrial viewpoint, it is preferable to select conditions so that the reaction time is 1 to 20 hours.

[0093] The reaction system for the hydrogenation reaction according to the present invention is not particularly limited, and examples of the reaction system that can be used include a liquid-phase suspension bed method in which a noble metal catalyst is dispersed in a reaction liquid, and a fixed-bed flow method in which a noble metal catalyst is fixed in a reactor and the reaction liquid is allowed to act on the catalyst.

[0094] After the reaction is complete, if the catalyst needs to be removed, the catalyst can be removed using a conventionally known method such as filtration or centrifugation to obtain the alkyl group-containing saturated cyclic ether (3). If necessary, the alkyl group-containing saturated cyclic ether (3) can be purified by distillation or the like to obtain a highly pure alkyl group-containing saturated cyclic ether (3).

[0095] The reaction product liquid containing the alkyl group-containing saturated cyclic ether (3) obtained by the hydrogenation reaction of the present invention can be subjected to phase separation and distillation in the same manner as in the reaction product liquid containing the alkyl group-containing unsaturated cyclic ether (2) described above, to recover the target alkyl group-containing saturated cyclic ether (3).

[0096] The alkyl group-containing saturated cyclic ether (3) produced by the method for producing an alkyl group-containing saturated cyclic ether of the present invention is a saturated cyclic ether obtained by adding a hydrogen atom to the double bond of the unsaturated cyclic ether of the alkyl group-containing unsaturated cyclic ether (2) produced by the method for producing an alkyl group-containing unsaturated cyclic ether of the present invention. For the same reasons as described above, the alkyl group-containing saturated cyclic ether (3) produced is preferably 2-methyltetrahydrofuran.

[0097] The method for producing an alkyl group-containing saturated cyclic ether of the present invention is industrially extremely useful as a method for producing 2-methylfuran by a hydrodeoxygenation reaction using furfural as a starting material in the presence of the present catalyst, and then producing 2-methyltetrahydrofuran by a hydrogenation reaction of 2-methylfuran. [Example]

[0098] The present invention will be described in more detail below with reference to examples and comparative examples. The present invention is not limited to the following examples as long as it does not depart from the gist of the invention. The following examples are merely illustrative and are not intended to limit any of the embodiments described herein. The following examples do not limit the invention in any way. The values ​​of various production conditions and evaluation results in the following examples are meant as preferred upper or lower limit values ​​in the embodiments of the present invention, and a preferred range may be defined by a combination of the above-mentioned upper or lower limit value and the values ​​of the following examples or values ​​of the examples themselves.

[0099] [raw materials] The abbreviations for the raw materials used in the examples and comparative examples are as follows: Copper-zinc-alumina catalyst (product name: N2B3 activated carbon supported, manufactured by JGC Catalysts and Chemicals Co., Ltd.) Copper chromium catalyst (product name: N-203SD activated carbon supported, manufactured by JGC Catalysts and Chemicals Co., Ltd.) Copper-iron-alumina catalyst (product name: N2A3 activated carbon supported, manufactured by JGC Catalysts and Chemicals Co., Ltd.) 5% Ru carbon catalyst (product name: B-Type, manufactured by N.E. Chemcat Corporation) 5% Pd carbon catalyst (product name: STD-Type, manufactured by N.E. Chemcat Corporation) 5% Pt carbon catalyst (manufactured by N.E. Chemcat Corporation)

[0100] [Evaluation method] In the following, the evaluation methods for each physical property value are as follows.

[0101] <Furfural conversion rate and yields of 2-methylfuran and by-products> The conversion rate of furfural and the yields of 2-methylfuran and by-products of the reaction solutions obtained in the Examples and Comparative Examples were measured according to the following procedures.

[0102] For the reaction solutions obtained in the examples and comparative examples, using a gas chromatograph (GC) measuring device, under the following measurement conditions, the composition analysis of furfural (FA) as the raw material, 2-methylfuran (2MeF) and 2-methyltetrahydrofuran (2MeTHF) as the target products, 1-pentanol (1POL), furfuryl alcohol (FOL), 2-methylhydroxytetrahydrofuran (THFOL), 1,2-pentanediol (12PDOL), 1,4-pentanediol (14PDOL) and other impurities as by-products was carried out. Examples of the other impurities include decomposition products or altered substances of FA, polymers of FOL, and the like.

[0103] 0.7 g of diglyme was added to the reaction solution as an internal standard substance, and 0.2 g of the solution obtained by adding a solvent to make it 10 g was sampled, and the solution further diluted 10-fold with a solvent was used as a GC analysis sample.

[0104] <GC Measurement Conditions> GC device: GC-2014 (device name, manufactured by Shimadzu Corporation) Detector: Flame ionization detector (FID) Carrier gas: Helium (flow rate 1 ml / min) Column: Capillary column DB-1 (manufactured by Agilent Technologies, size: length 60 m × inner diameter 0.25 mm, film thickness 0.25 μm) Column temperature: 50°C (holding time 5 minutes) → heating at 5°C / min → 150°C (no holding time) → heating at 15°C / min → 300°C (no holding time) Inlet temperature: 250°C Detector temperature: 300°C Sample volume: 1 μL (split ratio: 1 / 20) Quantification method: Internal standard method using diglyme as an internal standard substance

[0105] [Reference Example 1: Production of Catalyst A] As the carrier, a 1 mm cylindrical activated carbon (trade name: Norit R1 EXTRA, manufactured by NORIT) carrier was used, and catalyst A was produced by a method according to Example 4 of JP-A-2001-9277. A metal-supported material (hereinafter referred to as "metal-supported material 1") was prepared by loading the ruthenium, platinum, and tin in a metal chloride solution containing ruthenium chloride hydrate, chloroplatinic acid(IV) hexahydrate, and tin(II) chloride dihydrate onto the activated carbon. In preparing metal-supported material 1, the amount of the metal chloride solution used to impregnate the activated carbon was set to the same amount as the pore volume of the activated carbon. Ammonium bicarbonate was used in an amount twice as large as the amount of chlorine in the metal chloride, and an aqueous ammonium bicarbonate solution (pH = 8.5) was prepared with a concentration of 12 mass %. The metal-supported material 1 was added to this and treated according to the methods described in Examples 1 and 4 of JP 2001-9277 A. The treated metal-supported material 1 (approximately 2 g) was dried at 150°C for 2 hours under an argon flow (5 L / h) and then reduced at 500°C for 2 hours under a hydrogen flow (5 L / h). The metal oxide was then oxidized and stabilized under a nitrogen flow (2 L / h) with an oxygen concentration of 5.0% to obtain a metal oxide, which was designated as Catalyst A.

[0106] In the obtained catalyst A, the amounts of the metal elements charged were such that, when the entire charged amounts were supported, reduced with hydrogen, and oxidized and stabilized, the amounts were 5.5 parts by mass of Ru, 2.4 parts by mass of Pt, and 6.4 parts by mass of Sn relative to 100 parts by mass of the total mass of the carbonaceous support (the mass ratio of tin and platinum to ruthenium was 1.6).

[0107] Reference Example 2: Production of Catalyst B A metal oxide was prepared as catalyst B in the same manner as in Reference Example 1, except that chloroplatinic acid (IV) hexahydrate was not used. In the obtained catalyst B, the amounts of the metal elements charged were such that, when the entire charged amounts were supported, reduced with hydrogen, and oxidized and stabilized, the amounts of Ru were 5.0 parts by mass and Pt were 4.0 parts by mass (the mass ratio of platinum to ruthenium was 0.8) relative to 100 parts by mass of the total mass of the carbonaceous support.

[0108] Reference Example 3: Production of catalyst C A metal oxide was prepared as catalyst C in the same manner as in Reference Example 1, except that silica gel (product name: CAriACT Q-15, manufactured by Fuji Silysia Chemical Ltd.) was used as a carrier and the treatment with ammonium bicarbonate was not carried out. In the obtained catalyst C, the amounts of each metal element were such that, when the entire amount was supported, reduced with hydrogen, and oxidized and stabilized, the amounts of Ru were 5.5 parts by mass, Pt was 2.4 parts by mass, and Sn was 6.4 parts by mass (the weight ratio of tin and platinum to ruthenium was 1.6) relative to 100 parts by mass of the total mass of the silica gel carrier.

[0109] Reference Example 4: Preparation of catalyst D A metal-supported material was prepared in the same manner as in Reference Example 3, except that alumina (product name: JRC-ALO-5A, Catalysis Society Reference Catalyst) was used as the support. The metal-supported material was then reduced with hydrogen and oxidized and stabilized to obtain a metal oxide, which was designated Catalyst D. In the obtained catalyst D, the amounts of each metal element were such that, when the entire amount was supported, reduced with hydrogen, and oxidized and stabilized, the amounts were 5.5 parts by mass of Ru, 2.4 parts by mass of Pt, and 6.4 parts by mass of Sn relative to 100 parts by mass of the total mass of the alumina support (the mass ratio of tin and platinum to ruthenium was 1.6).

[0110] Example 1: Preparation of 2MeF A 70 mL spinner-stirred autoclave (AC) was charged with 1.00 g of FA, 4.00 g of dioxane as a solvent, and 0.6 g of catalyst A. The atmosphere inside the AC was then purged with nitrogen gas (1 MPa pressure) three times. The atmosphere inside the AC was then purged with hydrogen gas (3 MPa pressure) three times. The temperature inside the AC was then raised to 200°C with the hydrogen pressure inside the AC at 3 MPa, and the hydrodeoxygenation reaction of FA was carried out for 2 hours. After the reaction was completed, the temperature inside the AC was cooled to room temperature (25°C), and the atmosphere inside the AC was purged with nitrogen. While the atmosphere inside the AC was still purged with nitrogen, the reaction solution was withdrawn from the bottom of the AC. Gas chromatography analysis of the resulting reaction solution confirmed the formation of 2MeF. The analytical results are shown in Table 1.

[0111] [Example 2 and Comparative Examples 1 to 6: Types of Catalysts] 2MeF was produced in the same manner as in Example 1, except that the type of catalyst and the reaction temperature were changed as shown in Table 1. The analytical results are shown in Table 1.

[0112] [Table 1]

[0113] As shown in Table 1, in Examples 1 and 2, 2MeF was produced in high yield with few by-products. On the other hand, in Comparative Examples 1 to 6, the catalyst did not contain ruthenium and tin and / or platinum, so the yield of 2MeF was low and much by-products were produced.

[0114] [Reference Comparative Examples 7-8: Types of catalysts and carriers] 2MeF was produced in the same manner as in Example 1, except that the types of catalyst and carrier were changed as shown in Table 2. The analytical results are shown in Table 2, which also lists the results of Example 1.

[0115] [Table 2]

[0116] As shown in Table 2, in Reference Comparative Example 7, the support was silica instead of a carbonaceous support, so the yield of 2MeF was low. The production of alcohols as by-products was small, and the yield of the intermediate FOL was high. On the other hand, in Reference Comparative Example 8, the support was alumina (Al2O3) instead of a carbonaceous support, and therefore the yield of 2MeF was low. This is presumably because alumina has acid sites, which led to the progression of side reactions such as polymerization of raw materials and intermediates.

[0117] [Examples 3 to 5 and Comparative Example 9: Types of Solvents] 2MeF was produced in the same manner as in Example 1, except that the solvent in Example 1 was changed to one shown in Table 3. The analytical results are shown in Table 3. Table 3 also shows the results of Example 1.

[0118] [Table 3]

[0119] As shown in Table 3, in Examples 1 and 3 to 5, 2MeF was produced in high yield with few by-products. On the other hand, in Reference Comparative Example 9, water was used as the solvent, and therefore the hydrogen deoxygenation reaction of FA did not proceed, and 2MeF was not obtained.

[0120] [Examples 6 to 7 and Reference Comparative Example 10: Reaction Temperature] 2MeF was produced in the same manner as in Example 1, except that the reaction temperature was changed as shown in Table 4. The analytical results are shown in Table 4. Table 4 also shows the results of Example 1.

[0121] [Table 4]

[0122] As shown in Table 4, in Examples 1, 6 to 7, 2MeF was produced in high yield with few by-products. On the other hand, in Reference Comparative Example 10, the reaction temperature was low, so that the FA conversion rate and the yield of 2MeF were low, and a large amount of by-product (FOL) was produced.

[0123] Example 9: Preparation of 2MeTHF After obtaining a reaction solution under the same conditions as in Example 1, 0.1 g of a 5% Pd carbon catalyst was added to the reaction solution in the AC. The air in the AC was then purged with nitrogen gas (pressure 1 MPa) three times. The air in the AC was then purged with hydrogen gas (pressure 3 MPa) three times. The temperature in the AC was then raised to 180°C with the hydrogen pressure in the AC at 3 MPa, and the hydrogenation reaction of 2MeF in the reaction solution was carried out for two hours. After the reaction was completed, the temperature in the AC was cooled to room temperature (25°C), and the air in the AC was purged with nitrogen. While the air in the AC was still purged with nitrogen, the reaction solution was extracted from the bottom of the AC. The resulting reaction solution was analyzed by gas chromatography, confirming the production of 2MeTHF. The yield of 2MeTHF was 81.3%.

[0124] Although the present invention has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various modifications can be made without departing from the spirit and scope of the invention. This application is based on Japanese Patent Application No. 2023-037807, filed on March 10, 2023, the entire contents of which are incorporated by reference.

Claims

1. A catalyst for producing an alkyl group-containing unsaturated cyclic ether (2) from an unsaturated cyclic ether (1) having a formyl group or a hydroxymethyl group, comprising: Contains ruthenium and tin, and may further contain platinum; Regarding the mass ratio of tin and platinum to ruthenium, when both tin and platinum are contained, the mass ratio of the sum of tin and platinum to ruthenium is 0.4 or more, and when tin is contained but platinum is not contained, the mass ratio of tin to ruthenium is 0.4 or more; the catalyst is a metal-supported material in which at least ruthenium and tin are supported on a support, the support is a carbonaceous support, The amount of ruthenium supported is 1 part by mass or more per 100 parts by mass of the total mass of the catalyst. Catalyst for producing alkyl group-containing unsaturated cyclic ethers.

2. When both tin and platinum are contained, the mass ratio of the sum of tin and platinum to ruthenium is 1.8 or less, and when tin is contained but platinum is not contained, the mass ratio of tin to ruthenium is 1.8 or less. The catalyst for producing an alkyl group-containing unsaturated cyclic ether according to claim 1 .

3. The catalyst for producing alkyl group-containing unsaturated cyclic ethers according to claim 1, wherein the amount of ruthenium supported is 10 parts by mass or less per 100 parts by mass of the total mass of the catalyst.

4. 2. The catalyst for producing an alkyl group-containing unsaturated cyclic ether according to claim 1, wherein the unsaturated cyclic ether (1) is furfural and the unsaturated cyclic ether (2) is 2-methylfuran.

5. A method for producing an alkyl group-containing unsaturated cyclic ether, comprising a reaction step of subjecting an unsaturated cyclic ether (1) having a formyl group or a hydroxymethyl group to a hydrodeoxygenation reaction in the presence of the catalyst according to any one of claims 1 to 4 to obtain an alkyl group-containing unsaturated cyclic ether (2).

6. 6. The method for producing an alkyl group-containing unsaturated cyclic ether according to claim 5, wherein the hydrodeoxygenation reaction is a liquid phase reaction in the presence of an organic solvent.

7. 7. The method for producing an alkyl group-containing unsaturated cyclic ether according to claim 6, wherein the organic solvent is at least one selected from the group consisting of ether compounds, alcohol compounds, and ester compounds.

8. The method for producing an alkyl group-containing unsaturated cyclic ether according to claim 5, wherein the reaction temperature of the hydrodeoxygenation reaction is 185°C or higher.

9. 6. A method for producing an alkyl group-containing saturated cyclic ether, comprising: a hydrodeoxygenation step of obtaining an alkyl group-containing unsaturated cyclic ether by the method for producing an alkyl group-containing unsaturated cyclic ether according to claim 5; and a hydrogenation step of hydrogenating the obtained alkyl group-containing unsaturated cyclic ether in the presence of a noble metal catalyst containing at least one noble metal selected from Group 8 noble metals and Group 10 noble metals of the Periodic Table of the Elements to obtain an alkyl group-containing saturated cyclic ether.

10. 6. A method for producing an alkyl group-containing saturated cyclic ether, comprising: obtaining an alkyl group-containing unsaturated cyclic ether by the method for producing an alkyl group-containing unsaturated cyclic ether according to claim 5; and adding a noble metal catalyst containing at least one selected from the group consisting of Group 8 noble metals and Group 10 noble metals of the Periodic Table of the Elements to the obtained alkyl group-containing unsaturated cyclic ether, and subjecting the noble metal catalyst to a hydrogenation reaction to obtain an alkyl group-containing saturated cyclic ether.

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