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

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

[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.

[0002] Saturated cyclic ethers containing alkyl groups (hereinafter referred to as "alkyl group-containing saturated cyclic ethers"), particularly 2-methyltetrahydrofuran (2MeTHF), are important organic intermediates and excellent solvents. The boiling points of alkyl group-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 group-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 group-containing saturated cyclic ethers, particularly 2-methyltetrahydrofuran, have excellent compatibility with hydrocarbon compositions such as gasoline. Alkyl group-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 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 ether (hereinafter referred to as "formyl group- or hydroxymethyl group-containing unsaturated cyclic ethers"), are used.

[0004] Currently, 2-MeTHF is produced from furfural as a starting material via a two-stage catalytic hydrogenation reaction.

[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 group-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.

[0007] Special table 2010-531838 publication Special table 2010-531839 publication

[0008] In the technologies described in Patent Documents 1 and 2, the conversion rate of the raw material furfural was low in the first-stage reaction, and large amounts of 1-pentanol and 1,2-pentanediol were produced as by-products due to the ring-opening reaction of the furan ring in the raw material furfural, 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, which requires consideration of explosion prevention measures for the gases, which incurs costs. In addition, excessively large high-pressure gas equipment is required, which increases production costs. Furthermore, the use of continuous gas-phase reaction technology results in an extremely slow processing rate for the raw materials.

[0009] The present invention has been made in view of the problems of the prior art. An object of the present invention is to provide a catalyst for producing alkyl group-containing unsaturated cyclic ethers, such as 2-methylfuran, which can be used in a liquid phase reaction to produce alkyl group-containing unsaturated cyclic ethers, such as 2-methylfuran, using formyl group- or hydroxymethyl group-containing cyclic ethers, such as furfural, as a starting material, and which can produce alkyl group-containing unsaturated cyclic ethers, 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 alkyl group-containing unsaturated cyclic ethers, in which an alkyl group-containing unsaturated cyclic ether, such as 2-methylfuran, is produced from a formyl group- or hydroxymethyl group-containing unsaturated cyclic ether, such as furfural, using the catalyst for producing alkyl group-containing unsaturated cyclic ethers. Another object of the present invention is to provide a method for producing alkyl group-containing saturated cyclic ethers, in which an alkyl group-containing saturated cyclic ether, such as 2-methyltetrahydrofuran, corresponding to the alkyl group-containing unsaturated cyclic ether, is produced using the alkyl group-containing unsaturated cyclic ether, such as 2-methylfuran, obtained by the method for producing alkyl group-containing unsaturated cyclic ethers.

[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 this finding and is summarized as follows.

[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, the catalyst containing 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 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.

[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 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 to a hydrogenation reaction to obtain an alkyl group-containing saturated cyclic ether.

[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 facilities, compared to conventional methods using gaseous raw materials, thereby reducing production costs. Furthermore, when furfural, for example, 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 allows the production of alkyl group-containing unsaturated cyclic ethers such as 2-methylfuran in higher yield.

[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.

[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, "mass%" indicates the content ratio of a specified component contained in a total amount of 100% by mass. In this specification, "mass%" and "weight%", "ppm by mass" and "ppm by weight", and "parts by mass" and "parts by weight" are synonymous. 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 Ether] 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 a 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] Since this catalyst contains Ru / Sn.Pt, it is suitable as a catalyst for use in producing an alkyl group-containing unsaturated cyclic ether (2). Specifically, by using this catalyst as a catalyst for producing an alkyl 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), the unsaturated cyclic ether (2) can be produced in high yield with few by-products.

[0035] The present catalyst is usually used as a metal-supported catalyst in which the Ru / Sn.Pt is supported on a carrier, and is usually produced by subjecting the metal-supported Ru / Sn.Pt supported on a carrier to a reduction treatment with a reducing gas, followed by an oxidation stabilization treatment.

[0036] <Catalytically 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 present catalyst (when the present catalyst contains either tin or platinum, the mass ratio of the tin or platinum; when the present catalyst contains both tin and platinum, the total mass ratio) is not particularly limited. From the viewpoint of producing the unsaturated cyclic ether (2) with few by-products and in high yield, this mass ratio is preferably 0.4 to 1.8, more preferably 0.45 to 1.5, and more preferably 0.5 to 1.2. When 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 either tin or 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, the present 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) with few by-products and in high yield, 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 arbitrarily.

[0039] <Support> The present 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 can exert catalytic function not only on the surface of the Ru / Sn.Pt supported catalyst but also inside the pores where Ru / Sn.Pt is supported. For this reason, it is 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 the present catalyst is not particularly limited, and examples thereof include powder, granules, pellets, etc. Among these, granules and pellets are preferred from the viewpoint of improving operability. The size of the carrier used in the present catalyst is not particularly limited, but when converted into 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, the catalyst has high activity per unit weight and is easier to handle.

[0043] When the reaction using this catalyst is a completely mixed reaction, the particle size of the support is usually 50 μm or more, preferably 100 μm or more, and usually 3 mm or less, preferably 2 mm or less. A smaller particle size of the support is preferable because the activity per unit mass of the resulting catalyst is higher. If the particle size of the support is too small below the lower limit, it may be difficult to separate the reaction liquid from the catalyst. When the shape of the support is not spherical, the particle size of the support is determined by calculating the volume of the support and converting it into the diameter of a spherical particle of the same volume.

[0044] When the reaction using the present catalyst is a fixed bed reaction, the particle size of the carrier is usually 0.5 mm or more and 5 mm or less, preferably 4 mm or less, and more preferably 3 mm or less. If the particle size is smaller than the lower limit, operation may become difficult due to the pressure difference. If the particle size is larger than the upper limit, the reaction activity may decrease.

[0045] <Amount of Ru / Sn.Pt Supported> The amount of Ru / Sn.Pt supported on the carrier in the present catalyst is not particularly limited. For example, the lower limit of the amount of ruthenium supported is usually 1 part by mass or more, preferably 3 parts by mass or more, relative to 100 parts by mass of the total mass of the present catalyst. On the other hand, the upper limit of the amount of Ru / Sn.Pt supported is usually 10 parts by mass or less, preferably 8 parts by mass or less, relative to 100 parts by mass of the total mass of the present catalyst. The above upper and lower limits can be arbitrarily combined. 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, preferably 3 parts by mass or more and 8 parts by mass or less, relative to 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. On the other hand, 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 arbitrarily. For example, 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 and 15 parts by mass or less, 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 supported amount of Ru / Sn.Pt and other metals 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 supported amount of Ru / Sn.Pt and other metals 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 arbitrarily combined. For example, the total supported amount of Ru / Sn.Pt and other metals is usually 5 parts by mass or more and 40 parts by mass or less, preferably 8 parts by mass or more and 30 parts by mass or less, and more preferably 10 parts by mass or more and 20 parts by mass or less, relative to 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 metal components 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 for producing the present catalyst> There are no particular limitations on the method for producing the present catalyst. The present catalyst can be produced by, for example, appropriately optimizing the method for producing a catalyst described in paragraphs 0033 to 0079 of JP 2020-168628 A according to well-known techniques by a person skilled in the art.

[0051] [Formyl or Hydroxymethyl Group-Containing Unsaturated Cyclic Ether (1)] The formyl or hydroxymethyl group-containing unsaturated cyclic ether (1) to which the present catalyst is applied is not particularly limited, and 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 group-containing unsaturated cyclic ether (2) produced by the present catalyst, furfural, dihydropyran, and the like are preferred, and furfural is most preferred.

[0052] [Alkyl Group-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 the present catalyst is obtained by converting the formyl group or hydroxymethyl group to a methyl group through a hydrodeoxygenation reaction 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 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 for 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 an 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 an alkyl group-containing unsaturated cyclic ether (2) using the present catalyst is preferably a heterogeneous reaction in which a 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 group- or hydroxymethyl group-containing unsaturated cyclic ether (1) or a solution containing the formyl group- or hydroxymethyl group-containing unsaturated cyclic ether (1) with hydrogen (hydrogen gas), or may be a gas-solid two-phase reaction carried out by reacting a gaseous (vaporized) formyl group- or hydroxymethyl group-containing unsaturated cyclic ether (1) with hydrogen. In particular, from the viewpoint of suppressing the production of by-products due to, for example, cleavage of carbon-carbon bonds in the formyl group- or hydroxymethyl group-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 group- or hydroxymethyl group-containing unsaturated cyclic ether (1) with hydrogen in the presence of the present catalyst.

[0057] The solvent used in the liquid phase reaction can be appropriately selected depending on the type of formyl group- or hydroxymethyl group-containing unsaturated cyclic ether (1) and is not particularly limited. 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; alcohol 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; and 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 group- or hydroxymethyl group-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, based on the formyl group- or hydroxymethyl group-containing unsaturated cyclic ether (1) in terms of Ru / Sn.Pt metal equivalent. On the other hand, the upper limit of the amount of the catalyst used is not particularly limited, but from the viewpoint of economic efficiency, it is preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 18% by mass or less, based on the formyl group- or hydroxymethyl group-containing unsaturated cyclic ether (1) in terms of Ru / Sn.Pt metal equivalent. The above upper and lower limits can be arbitrarily combined. For example, the amount of the catalyst used in the hydrodeoxygenation reaction is preferably 2 to 25% by mass, more preferably 5 to 20% by mass, and even more preferably 8 to 18% by mass, based on the formyl group- or hydroxymethyl group-containing unsaturated cyclic ether (1) in terms of Ru / Sn.Pt metal equivalent.

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

[0063] In the hydrodeoxygenation reaction, components other than the formyl group- or hydroxymethyl group-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, it 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, it 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 arbitrarily combined. 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 (the 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 arbitrarily. For example, the reaction pressure in the hydrodeoxygenation reaction is not particularly limited, but is usually 0.1 to 20 MPa, 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. Examples of such other steps include 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 target product from 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] Although phase separation can be carried out at room temperature (about 25°C), the alkyl group-containing unsaturated cyclic ether (2) has a lower solubility in water at lower temperatures, and therefore, it is preferable to carry out phase separation at 20°C or lower, for example, at 5 to 15°C.

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

[0076] [Method for 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 corresponding to the alkyl group-containing unsaturated cyclic ether (2) (hereinafter, sometimes referred to as "alkyl group-containing saturated cyclic ether (3)").

[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 carry out a hydrogenation reaction, thereby obtaining an alkyl group-containing saturated cyclic ether (3).

[0078] <Noble 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, which is 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, support-supported catalysts in which noble metals are supported on a support, various organic compounds such as acetylacetonate compounds, and various complex compounds such as amine complexes, phosphine complexes, and carbonyl compounds. These can be used either 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 carriers used in the carrier-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 carriers 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 catalysts, Rh-carbon catalysts, Pd-carbon catalysts, Ru-alumina catalysts, Rh-alumina catalysts, and Pd-alumina catalysts. Among these, Pd-carbon catalysts and Pd-alumina catalysts 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 selected as appropriate for the reaction system selected, such as a powder or molded catalyst. Powdered catalysts are typically used in batch or continuous liquid-phase suspension bed hydrogenation reactions. Molded catalysts are typically used in fixed-bed flow-type hydrogenation reactions. The molded catalyst is selected appropriately depending on the size of the reactor used. The molded catalyst is typically preferably cylindrical 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 in the absence of 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 reaction solvents 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; Examples of suitable solvents include 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; and amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone. 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 under which the hydrogenation reaction can be completed. Under conditions under which a practical reaction rate can be obtained, 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 allows the hydrogenation reaction to be completed. The reaction temperature is usually 20 to 200°C, preferably 40 to 180°C, under conditions that allow a practical reaction rate to be obtained. 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, which tends to reduce the yield.

[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 alkyl group-containing saturated cyclic ether (3) can be obtained by removing the catalyst using a conventionally known method such as filtration or centrifugation. 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, 2-methyltetrahydrofuran is a preferred example of the alkyl group-containing saturated cyclic ether (3) produced.

[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.

[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 present 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 present invention in any way. The values ​​of various production conditions and evaluation results in the following examples represent preferred upper or lower limit values ​​in the embodiments of the present invention, and preferred ranges may be defined by combining the above-mentioned upper or lower limit values ​​with the values ​​of the following examples or values ​​between the examples.

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

[0100] [Evaluation Method] Hereinafter, the evaluation method for each physical property value is as follows.

[0101] <Furfural Conversion Rate and Yields of 2-Methylfuran and By-Products> The furfural conversion rate and 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] The reaction solutions obtained in the examples and comparative examples were analyzed for composition using a gas chromatograph (GC) under the following measurement conditions: raw material furfural (FA), target products 2-methylfuran (2MeF) and 2-methyltetrahydrofuran (2MeTHF), by-products 1-pentanol (1POL), furfuryl alcohol (FOL), 2-methylhydroxytetrahydrofuran (THFOL), 1,2-pentanediol (12PDOL), 1,4-pentanediol (14PDOL), and other impurities. Examples of the other impurities include decomposition products or altered products of FA, and polymers of FOL.

[0103] To the reaction solution, 0.7 g of diglyme was added as an internal standard substance, and a solvent was added to make the total volume 10 g, and 0.2 g of the solution was sampled and further diluted 10 times with the solvent to prepare a sample for GC analysis.

[0104] <GC measurement conditions> GC apparatus: GC-2014 (apparatus name, manufactured by Shimadzu Corporation) Detector: Hydrogen 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 x inner diameter 0.25 mm, film thickness 0.25 μm) Column temperature: 50°C (hold time 5 min) → temperature increase at 5°C / min → 150°C (no hold time) → temperature increase at 15°C / min → 300°C (no hold time) Injection port temperature: 250°C Detector temperature: 300°C Sample volume: 1 μL (split ratio: 1 / 20) Quantitative method: Internal standard method using diglyme as an internal standard substance

[0105] Reference Example 1: Production of Catalyst A Catalyst A was produced using a 1 mm cylindrical activated carbon (trade name: Norit R1 EXTRA, manufactured by NORIT Corporation) as the support, according to Example 4 of JP 2001-9277 A. An aqueous solution of metal chlorides containing ruthenium chloride hydrate, chloroplatinic acid (IV) hexahydrate, and tin (II) chloride dihydrate was used to support the ruthenium, platinum, and tin in the metal chlorides on the activated carbon, thereby preparing a metal-supported material (hereinafter referred to as "metal-supported material 1"). In preparing metal-supported material 1, the amount of the metal chloride aqueous solution used to impregnate the activated carbon was the same as the pore volume of the activated carbon. Ammonium bicarbonate was used in an amount twice the molar amount relative to the chlorine of the metal chloride, and an ammonium bicarbonate aqueous solution (pH = 8.5) adjusted to a concentration of 12 mass % was prepared, to which the metal-supported material 1 was added, and treatment was carried out 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). Thereafter, the metal oxide was 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 of Ru were 5.5 parts by mass, Pt was 2.4 parts by mass, and Sn was 6.4 parts by mass (the mass ratio of tin and platinum to ruthenium was 1.6) relative to 100 parts by mass of the total mass of the carbonaceous support.

[0107] Reference Example 2: Production of catalyst B A metal oxide was prepared in the same manner as in Reference Example 1, except that chloroplatinic acid (IV) hexahydrate was not used, and this was designated catalyst B. 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 in the same manner as in Reference Example 1, except that silica gel (trade name: CARiACT Q-15, manufactured by Fuji Silysia Chemical Ltd.) was used as the support, and the treatment with ammonium bicarbonate was not carried out. This was designated as catalyst C. The amounts of the metal elements charged in the resulting catalyst C were such that, when the entire charged amounts were supported, reduced with hydrogen, and stabilized by oxidation, 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 silica gel support (the weight ratio of tin and platinum to ruthenium was 1.6).

[0109] Reference Example 4: Production of catalyst D A metal-supported material was prepared by a method similar to Reference Example 3, except that alumina (product name: JRC-ALO-5A, Catalysis Society reference catalyst) was used as the support, and then the metal-supported material was reduced with hydrogen and oxidized and stabilized to obtain a metal oxide, which was designated catalyst D. In the resulting catalyst D, the amounts of each metal element charged were such that, when the entire charged amount was supported and subjected to hydrogen reduction and oxidization and stabilization, 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: Production of 2MeF Into a 70 mL spinner-stirred autoclave (AC), 1.00 g of FA, 4.00 g of dioxane as a solvent, and 0.6 g of catalyst A were placed. The AC was then purged with nitrogen gas (pressure 1 MPa) three times. The AC was then purged with hydrogen gas (pressure 3 MPa) 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 FA was subjected to a hydrodeoxygenation reaction for 2 hours. After completion of the reaction, the temperature inside the AC was cooled to room temperature (25°C), and the AC was purged with nitrogen. While 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 2MeF. The analytical results are shown in Table 1.

[0111] [Example 2 and Comparative Examples 1 to 6: Type of Catalyst] 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]

[0113] As shown in Table 1, 2MeF was produced in high yield with few by-products in Examples 1 and 2. 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 many by-products were produced.

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

[0115]

[0116] As shown in Table 2, in Reference Comparative Example 7, the support was silica instead of a carbonaceous support, and therefore the yield of 2MeF was low. The production of alcohols as by-products was low, and the yield of the intermediate FOL was high. On the other hand, in Reference Comparative Example 8, the support was alumina (Al ２ O ３ ), the yield of 2MeF was low. This is presumably because alumina has acid sites, which causes side reactions such as polymerization of raw materials and intermediates.

[0117] [Examples 3 to 5 and Reference Comparative Example 9: Kind of Solvent] 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]

[0119] As shown in Table 3, 2MeF was produced in high yield with few by-products in Examples 1 and 3 to 5. On the other hand, in Reference Comparative Example 9, because water was used as the solvent, the hydrodeoxygenation 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 in Example 1 was changed as shown in Table 4. The analytical results are shown in Table 4. Table 4 also lists the results of Example 1.

[0121]

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

[0123] Example 9: Production 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 completion of the reaction, 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 using 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 present invention. This application is based on Japanese Patent Application No. 2023-037807, filed on March 10, 2023, and is incorporated by reference in its entirety.

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: A catalyst for producing an alkyl group-containing unsaturated cyclic ether, which contains ruthenium and at least one of tin and platinum.

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

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

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

5. 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.

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 claims 1 to 5 to obtain an alkyl group-containing unsaturated cyclic ether (2).

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

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

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

10. 7. 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 6; and a hydrogenation step of hydrogenating the obtained alkyl group-containing unsaturated cyclic ether in the presence of a precious metal catalyst containing at least one selected from the group consisting of Group 8 precious metals and Group 10 precious metals of the Periodic Table of the Elements, to obtain an alkyl group-containing saturated cyclic ether.

11. 7. 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 6; and adding a precious metal catalyst containing at least one selected from the group consisting of Group 8 precious metals and Group 10 precious metals of the Periodic Table of the Elements to the obtained alkyl group-containing unsaturated cyclic ether to carry out a hydrogenation reaction to obtain an alkyl group-containing saturated cyclic ether.