Method for producing gamma-butyrolactone and method for producing N-methylpyrrolidone

Abstract

Provided is a method for producing gamma-butyrolactone, said method including a reaction step in which a raw material composed of one or both of 2-hydroxytetrahydrofuran and 4-hydroxybutyraldehyde and a catalyst containing copper and an oxide of at least one metal element selected from the group consisting of zinc, zirconium, and aluminum are brought into contact with each other at a reaction temperature higher than 200°C to generate gamma-butyrolactone.

Description

[Technical field]

[0001] The present invention relates to a method for producing gamma-butyrolactone and a method for producing N-methylpyrrolidone. This application claims priority based on Japanese Patent Application No. 2019-162951, filed on September 6, 2019, the contents of which are incorporated herein by reference. [Background technology]

[0002] In recent years, the use of lithium ion secondary batteries (LIB batteries) has been increasing. Accordingly, the demand for N-methylpyrrolidone (NMP), which is used as a binder solvent in LIB batteries, is increasing. Therefore, it is desirable to produce gamma-butyrolactone (GBL), which is used as a raw material for NMP, efficiently and at low cost.

[0003] Conventionally, a method using a dehydrogenation reaction of 1,4-butanediol (1,4-BDO) has been widely used industrially as a method for producing gamma-butyrolactone. As a method for producing gamma-butyrolactone by a dehydrogenation reaction of 1,4-butanediol, there is a method described in Patent Document 1 or Patent Document 2.

[0004] In Patent Document 1, Cu-ZnO-Al 2 O 3 -ZrO 2 This document describes a method for producing lactones, which comprises contacting 1,4-butanediol (1,4-BDO) in a gas phase with a catalyst represented by the formula: Patent Document 2 describes the use of a catalyst containing a platinum and a bismuth compound in a method for producing γ-butyrolactone by oxidative dehydrogenation of 1,4-butanediol in the presence of molecular oxygen.

[0005] Another method for producing gamma-butyrolactone is to hydrogenate a dicarboxylic acid diester with hydrogen in the gas phase in the presence of a supported catalyst carrying copper metal and silver metal. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2002-371075 A [Patent Document 2] Japanese Patent Application Publication No. 5-286959 Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the conventional method for producing gamma-butyrolactone, there was a demand for improving productivity. In particular, when producing gamma-butyrolactone by dehydrogenation of 1,4-butanediol, the reactivity of 1,4-butanediol is low, so that the reaction must be continued for a long time in order to produce sufficient gamma-butyrolactone. As a result, the productivity was insufficient.

[0008] In addition, 1,4-butanediol, which is used as a raw material for gamma-butyrolactone, is generally produced using two reactions: a reaction to produce a mixture of 2-hydroxytetrahydrofuran (2HTHF) and 4-hydroxybutyraldehyde (4-HBA) from allyl alcohol, and a reaction to reduce the resulting mixture. Therefore, when producing gamma-butyrolactone using 1,4-butanediol as a raw material, the production of the raw material is troublesome, which has been a problem.

[0009] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a method for producing gamma-butyrolactone with good productivity. Another object of the present invention is to provide a method for producing N-methylpyrrolidone, which efficiently produces N-methylpyrrolidone using gamma-butyrolactone produced by the method for producing gamma-butyrolactone of the present invention. [Means for solving the problem]

[0010] The present inventors have conducted extensive research to solve the above problems. As a result, they discovered that gamma-butyrolactone can be produced efficiently by contacting raw materials consisting of 2-hydroxytetrahydrofuran and / or 4-hydroxybutyraldehyde with a specific catalyst at a reaction temperature of over 200°C to produce gamma-butyrolactone. That is, a first aspect of the present invention is the following method for producing gamma-butyrolactone.

[0011] [1] A method for producing gamma-butyrolactone, comprising a reaction step of contacting a raw material consisting of one or both of 2-hydroxytetrahydrofuran and 4-hydroxybutyraldehyde with a catalyst containing an oxide of at least one metal element selected from the group consisting of zinc, zirconium and aluminum and copper at a reaction temperature of more than 200°C to produce gamma-butyrolactone.

[0012] The method for producing gamma-butyrolactone according to the first aspect of the present invention can preferably include the following features, as described below. Two or more of the following features may be preferably combined. [2] The method for producing gamma-butyrolactone according to [1], wherein in the reaction step, an aqueous solution containing 1 to 30 mass % of the raw materials is vaporized and brought into contact with the catalyst. [3] In the reaction step, the raw material is vaporized and heated to a temperature of 20,000 to 300,000 h 2 for the catalyst. -1 The method for producing gamma-butyrolactone according to [1] or [2], comprising contacting the

[0013] [4] The method for producing gamma-butyrolactone according to any one of [1] to [3], wherein in the reaction step, the raw material and the catalyst are contacted at a reaction temperature of 400° C. or lower. [5] The method for producing gamma-butyrolactone according to any one of [1] to [4], wherein the catalyst contains oxides of zinc, zirconium and aluminum, and metallic copper. [6] The method for producing gamma-butyrolactone according to any one of [1] to [5], wherein the catalyst further contains an oxide of chromium.

[0014] [7] Prior to the reaction step, Carbon monoxide and hydrogen (H 2 The method for producing gamma-butyrolactone according to any one of [1] to [6], further comprising a raw material production step of producing the raw material by hydroformylating allyl alcohol using a mixed gas of 1,2-dichlorophenyl ether and 1,2-dichlorophenyl ether. [8] The method for producing gamma-butyrolactone according to [7], wherein in the raw material production step, the allyl alcohol is subjected to a hydroformylation reaction in the presence of a catalyst comprising an organophosphorus compound ligand and a rhodium complex.

[0015] [9] The method for producing gamma-butyrolactone according to [7] or [8], wherein the mixed gas has a molar ratio of hydrogen to carbon monoxide of 0.1 to 10.

[10] The method for producing gamma-butyrolactone according to any one of [7] to [9], wherein the hydroformylation reaction of allyl alcohol is carried out at a reaction pressure of 0.1 to 10 MPa.

[0016]

[11] The method for producing gamma-butyrolactone according to any one of [7] to

[10] , wherein the hydroformylation reaction of allyl alcohol is carried out at a reaction temperature of 0 to 150° C.

[12] The method for producing gamma-butyrolactone according to any one of [1] to

[11] , wherein the catalyst contains 0.01 to 0.2 mol of zinc, 0.01 to 1 mol of zirconium, and 0.05 to 3 mol of aluminum per mol of copper.

[13] The method for producing gamma-butyrolactone according to any one of [6] to

[11] , wherein the catalyst contains 0.01 to 0.5 mol of zinc, 0.01 to 1 mol of zirconium, 0.05 to 3 mol of aluminum, and 0.01 to 0.3 mol of chromium per mol of copper.

[0017] A second aspect of the present invention is a method for producing N-methylpyrrolidone as follows.

[14] A step of producing gamma-butyrolactone using the method for producing gamma-butyrolactone according to any one of [1] to

[13] ; and reacting the produced gamma-butyrolactone with monomethylamine. A third aspect of the present invention is the following catalyst:

[15] A catalyst for producing gamma-butyrolactone, comprising an oxide of at least one metal element selected from the group consisting of zinc, zirconium, and aluminum, and copper. The catalyst according to the third aspect of the present invention may preferably include the following features, as described below. Two or more of the following features may preferably be combined.

[16] The catalyst according to

[15] , which is used in the production of gamma-butyrolactone from raw materials consisting of one or both of 2-hydroxytetrahydrofuran and 4-hydroxybutyraldehyde.

[17] The catalyst according to

[15] or

[16] , wherein the catalyst contains oxides of zinc, zirconium and aluminum, and metallic copper.

[18] The catalyst according to any one of

[15] to

[17] , further comprising an oxide of chromium.

[19] The catalyst according to any one of

[15] to

[18] , wherein the catalyst contains 0.01 to 0.2 mol of zinc, 0.01 to 1 mol of zirconium, and 0.05 to 3 mol of aluminum per mol of copper.

[20] The catalyst according to

[18] , wherein the catalyst contains 0.01 to 0.5 mol of zinc, 0.01 to 1 mol of zirconium, 0.05 to 3 mol of aluminum, and 0.01 to 0.3 mol of chromium relative to 1 mol of copper. Effect of the Invention

[0018] The method for producing gamma-butyrolactone of the present invention uses raw materials consisting of 2-hydroxytetrahydrofuran and / or 4-hydroxybutyraldehyde. This raw material can be easily produced using only one reaction, namely hydroformylation of allyl alcohol, and has good reactivity. By contacting the raw material with a catalyst containing copper and an oxide of at least one metal element selected from the group consisting of zinc, zirconium, and aluminum at a reaction temperature of over 200°C, gamma-butyrolactone is rapidly produced. Therefore, the method for producing gamma-butyrolactone of the present invention has excellent productivity.

[0019] Furthermore, according to the method for producing N-methylpyrrolidone of the present invention, since gamma-butyrolactone is produced using the method for producing gamma-butyrolactone of the present invention, N-methylpyrrolidone can be produced efficiently. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Preferred examples of the method for producing gamma-butyrolactone and the method for producing N-methylpyrrolidone of the present invention will be described in detail below. Note that the present invention is not limited to the following embodiments. Within the scope of the present invention, the number, position, type, amount, ratio, combination, numerical value, etc. can be omitted, changed, and / or added as necessary.

[0021] <Method of producing gamma-butyrolactone> The method for producing gamma-butyrolactone of the present embodiment includes a reaction step of contacting a raw material consisting of 2-hydroxytetrahydrofuran (2HTHF) represented by the following formula (1) and / or 4-hydroxybutyraldehyde (4-HBA) represented by the following formula (2) with a catalyst described below at a reaction temperature of more than 200° C. to produce gamma-butyrolactone (GBL) represented by the following formula (3).

[0022] [ka]

[0023] 2HTHF and 4-HBA are in equilibrium in solution. When the structure of an aqueous solution containing 2HTHF and 4-HBA was confirmed using a nuclear magnetic resonance (NMR) device, it was confirmed that 2HTHF was present as the main component. For this reason, 2HTHF and / or 4-HBA may be referred to as "2HTHF, etc." below. In addition, since 4-HBA is an unstable compound, it is difficult to imagine using it as a raw material (starting material) when producing gamma-butyrolactone or the like.

[0024] The raw material 2HTHF etc. used in the production method of this embodiment may be a commercially available product, may be produced by subjecting 2,3-dihydrofuran to a hydration reaction, or may be produced by carrying out the raw material production step described below. The raw material 2HTHF etc. can be easily produced using only one reaction by carrying out the raw material production step described below prior to the reaction step. The ratio of 2HTHF and 4-HBA in 2HTHF etc. used as a raw material is not particularly limited. 2HTHF may be the majority due to the above-mentioned equilibrium relationship. When both 2HTHF and 4-HBA are contained, the ratio (molar ratio) of 2HTHF and 4-HBA in water or an organic solvent such as chloroform may be, for example, 2HTHF / 4-HBA=1 to 50, 2HTHF / 4-HBA=1 to 30, or 2HTHF / 4-HBA=1 to 10. The ratio may be 0.01 to 50, 0.1 to 20, 0.5 to 5, etc.

[0025] (Raw material generation process) In this embodiment, it is preferable to carry out a raw material production step before the reaction step. In the raw material production step, carbon monoxide and hydrogen (H 2 A raw material (such as 2HTHF) is produced by hydroformylating allyl alcohol (AAL) using a mixed gas of 2HTHF and 2H2O. The hydroformylation of allyl alcohol is preferably carried out in the presence of a catalyst.

[0026] The raw material production step may be carried out, for example, by placing allyl alcohol and a catalyst and / or a solvent, which may be used as necessary, in a reaction vessel, and then adding carbon monoxide (CO) and hydrogen (H 2 ) into the tank, and allyl alcohol (AAL) is hydroformylated. In this case, the reaction vessel may be, for example, a stainless steel pressure-resistant reaction vessel.

[0027] The mixed gas of carbon monoxide and hydrogen used preferably has a molar ratio of hydrogen to carbon monoxide in the range of 0.1 to 10, more preferably 0.5 to 5, and further preferably 0.8 to 2. When the molar ratio of hydrogen to carbon monoxide is in the range of 0.1 to 10, the hydroformylation reaction is promoted, and 2HTHF and the like can be produced in a higher yield.

[0028] As the catalyst, it is preferable to use an organic phosphorus compound ligand and a rhodium complex, and it is more preferable that the organic phosphorus compound ligand is a bidentate diphosphine ligand. For example, the bidentate diphosphine ligand may be trans-4,5-bis(diphenylphosphinomethyl)-2,2-dimethyl-1,3-dioxolane (DIOP). In the presence of a catalyst consisting of an organic phosphorus compound ligand and a rhodium complex, i.e., a catalyst in which a rhodium complex is coordinated to an organic phosphorus compound ligand, 2HTHF and the like can be produced in a higher yield by hydroformylating allyl alcohol. The amount of catalyst added is not particularly limited, but is preferably 0.01 to 100 mmol, more preferably 0.1 to 50 mmol, and even more preferably 1 to 5 mmol, per liter of the reaction liquid.

[0029] As the solvent, aromatic hydrocarbons, saturated hydrocarbons, ethers, esters, etc. can be preferably used. As the solvent, it is particularly preferable to use aromatic hydrocarbons, and specifically, it is preferable to use toluene.

[0030] In order to promote the hydroformylation reaction and produce 2HTHF and the like in a higher yield, the hydroformylation reaction of allyl alcohol is preferably carried out at an absolute reaction pressure of 0.1 to 10 MPa, more preferably 0.5 to 8 MPa, and even more preferably 1 to 4 MPa.

[0031] In order to promote the hydroformylation reaction and produce 2HTHF or the like in a higher yield, the hydroformylation reaction of allyl alcohol is preferably carried out at a reaction temperature of 0 to 150°C, more preferably 20 to 100°C, and even more preferably 40 to 80°C. The reaction time for the hydroformylation reaction of allyl alcohol is preferably 0.5 to 10 hours, more preferably 1 to 7 hours, and further preferably 3 to 5 hours.

[0032] The 2HTHF and other products produced by the hydroformylation reaction of allyl alcohol are preferably purified by extraction with water or distillation before use as a raw material in the reaction step.

[0033] (Reaction process) Next, in this embodiment, the raw material material (2HTHF, etc.) produced in the raw material production process is contacted with a catalyst at a reaction temperature of more than 200°C to carry out a dehydrogenation reaction of 2HTHF, etc., to produce gamma-butyrolactone (GBL). The reaction apparatus used in the reaction step may be, for example, a fixed-bed gas phase reaction apparatus.

[0034] "catalyst" The catalyst to be contacted with the raw material in the reaction step is a catalyst containing at least one metal element oxide selected from the group consisting of zinc, zirconium, and aluminum, and copper. Copper is essential, but one or two of zinc oxide, zirconium oxide, and aluminum oxide may not be contained in the catalyst. However, it is preferable to contain all of the oxides. Specific examples of the catalyst include a catalyst containing zinc oxide and metallic copper (CuZnOx); a catalyst containing zirconium oxide and metallic copper (CuZrOx); a catalyst containing aluminum oxide and metallic copper (CuAlOx); a catalyst containing zinc and aluminum oxide, and metallic copper (CuZnAlOx); a catalyst containing zirconium and aluminum oxide, and metallic copper (CuZrAlOx); a catalyst containing zinc and zirconium oxide, and metallic copper (CuZnZrOx); a catalyst containing zinc, zirconium, and aluminum oxide, and metallic copper (CuZnZrAlOx), and the like. In the above formula, x may be any number selected, for example, x may be 0.01 to 18.5, 0.01 to 10.0, 0.03 to 6.0, or 0.05 to 2.0. The catalyst is preferably one containing oxides of zinc, zirconium, and aluminum, and metallic copper, since it can further promote the reaction of producing gamma-butyrolactone. The catalyst may be one consisting of copper, at least one selected from the group consisting of zinc, zirconium, and aluminum, and oxygen.

[0035] When the catalyst contains each oxide of zinc, zirconium, and aluminum, and metallic copper, the reaction to produce gamma-butyrolactone can be further promoted. The amount of the oxide and metallic copper can be selected arbitrarily. In order to further promote the reaction, the content of each metal in the catalyst is preferably 1 mole or less of zinc, 5 moles or less of zirconium, and 5 moles or less of aluminum per mole of copper. The lower limit of each of the zinc, zirconium, and aluminum may be 0 mole. The content of each metal in the catalyst is more preferably 0.01 to 0.1 mole of zinc, 0.01 to 1 mole of zirconium, and 0.05 to 3 moles of aluminum per mole of copper, and further preferably 0.01 to 0.05 moles of zinc, 0.05 to 0.2 moles of zirconium, and 0.1 to 1 mole of aluminum per mole of copper. The amount of zinc in the catalyst per mole of copper is preferably 1.0 mole or less, more preferably 0.005 to 0.3 moles, even more preferably 0.01 to 0.2 moles, even more preferably 0.01 to 0.1 moles, and particularly preferably 0.01 to 0.05 moles. The amount of zirconium in the catalyst is preferably 5.0 mol or less, more preferably 0.01 to 1 mol, even more preferably 0.05 to 0.4 mol, even more preferably 0.05 to 0.3 mol, and particularly preferably 0.10 to 0.2 mol, per mol of copper. The amount of aluminum in the catalyst per mole of copper is preferably 5.0 moles or less, more preferably 0.01 to 3.0 moles, even more preferably 0.05 to 1.0 moles, even more preferably 0.1 to 0.8 moles, and particularly preferably 0.2 to 0.6 moles. However, the content of each metal in the catalyst can be selected arbitrarily and is not limited to the above ranges.

[0036] The catalyst to be contacted with the raw material may further contain other metal oxides in addition to copper and at least one metal element oxide selected from the group consisting of zinc, zirconium, and aluminum. The other metal oxide is preferably chromium oxide. When the catalyst used in the production method of the present invention contains chromium oxide, specific examples of the catalyst include catalysts containing zinc and chromium oxides and metallic copper (CuZnCrOx); catalysts containing zirconium and chromium oxides and metallic copper (CuZrCrOx); catalysts containing aluminum and chromium oxides and metallic copper (CuAlCrOx); catalysts containing zinc, zirconium, and chromium oxides and metallic copper (CuZnZrCrOx); catalysts containing zinc, aluminum, and chromium oxides and metallic copper (CuZnAlCrOx); catalysts containing zirconium, aluminum, and chromium oxides and metallic copper (CuZrAlCrOx); catalysts containing zinc, zirconium, aluminum, and chromium oxides and metallic copper (CuZnZrAlCrOx); and the like. In the above formula, x may be any number selected, and for example, x may be 0.025 to 13.5, 0.045 to 10.5, 0.065 to 6.5, or 0.085 to 2.25. The catalyst preferably consists of only copper, at least one selected from the group consisting of zinc, zirconium, and aluminum, chromium, and oxygen.

[0037] When the catalyst contains chromium oxide in addition to each oxide of zinc, zirconium and aluminum, and metallic copper, it is expected that the activation of the reaction due to lowering the activation barrier of the dehydrogenation reaction can be expected. Therefore, it is more preferable as a catalyst to be used. Since the reaction to generate gamma-butyrolactone can be further promoted, the content of each metal in the catalyst is preferably 1 mole or less of zinc, 2 moles or less of zirconium, 5 moles or less of aluminum, and 0.5 moles or less of chromium per mole of copper. The content of each metal in the catalyst is more preferably 0.01 to 0.5 moles of zinc, 0.01 to 1 moles of zirconium, 0.05 to 3 moles of aluminum, and 0.01 to 0.3 moles of chromium per mole of copper, and further preferably 0.05 to 0.2 moles of zinc, 0.05 to 0.3 moles of zirconium, 0.1 to 1 moles of aluminum, and 0.05 to 0.2 moles of chromium per mole of copper. The amount of zinc in the catalyst per mole of copper is preferably 1.0 mole or less, more preferably 0.005 to 0.3 moles, even more preferably 0.01 to 0.2 moles, even more preferably 0.01 to 0.1 moles, and particularly preferably 0.01 to 0.05 moles. The amount of zirconium in the catalyst is preferably 5.0 mol or less, more preferably 0.01 to 1 mol, even more preferably 0.05 to 0.4 mol, even more preferably 0.05 to 0.3 mol, and particularly preferably 0.10 to 0.2 mol, per mol of copper. The amount of aluminum in the catalyst per mole of copper is preferably 5.0 moles or less, more preferably 0.01 to 3.0 moles, even more preferably 0.05 to 1.0 moles, even more preferably 0.1 to 0.8 moles, and particularly preferably 0.2 to 0.6 moles. The amount of chromium in the catalyst per mole of copper is preferably 0.5 moles or less, more preferably 0.01 to 0.4 moles, more preferably 0.03 to 0.3 moles, more preferably 0.05 to 0.2 moles, and even more preferably 0.07 to 0.15 moles. However, the content of each metal in the catalyst can be selected arbitrarily and is not limited to the above ranges. By including chromium oxide in the catalyst, it is expected that the production of 1,4-butanediol caused by the reduction of 2HTHF, etc. can be suppressed, and side reactions that produce 1,4-butanediol and other impurities can be suppressed, thereby improving selectivity.

[0038] [Catalyst manufacturing method] The method for producing the catalyst is not particularly limited and can be selected arbitrarily, but for example, a coprecipitation method, a hydrothermal method, a sol-gel method, etc. can be used, and among them, the coprecipitation method is preferably used. When the coprecipitation method is used, the catalyst can be prepared, for example, by the following procedure.

[0039] First, a precursor of a metal of a type and amount corresponding to the composition of the target catalyst is dissolved in water to prepare a precursor aqueous solution. Examples of the metal include copper, zinc, zirconium, aluminum, and chromium. Next, while stirring the precursor aqueous solution, a basic aqueous solution is dropped into the precursor aqueous solution to generate a precipitate. The precipitate is then collected by filtration, washed with water, and dried. The dried precipitate is calcined to form an oxide, and then hydrogen reduction is performed, specifically hydrogen reduction of the obtained copper oxide. Since oxides of zinc, zirconium, aluminum, and chromium are difficult to reduce with hydrogen, mainly copper oxide is reduced to metallic copper. The catalyst is obtained by the above steps.

[0040] Examples of the precursor of each metal used in the above-mentioned catalyst manufacturing method include nitrates, acetates, carbonates, and oxalates, among which nitrates are preferably used. As the basic aqueous solution, an ammonia aqueous solution and / or an alkali hydroxide aqueous solution can be preferably used. Among them, as the basic aqueous solution, an alkali hydroxide aqueous solution is preferably used. Specific examples of the alkali hydroxide aqueous solution include lithium hydroxide, sodium hydroxide, potassium hydroxide, magnesium hydroxide, and calcium hydroxide, among which sodium hydroxide is preferably used.

[0041] In the above-mentioned catalyst production method, in the step of dripping the basic aqueous solution into the precursor aqueous solution to generate a precipitate, the pH at the end of the dripping is preferably 5 to 10, and more preferably 6 to 8. If the pH at the end of the dripping is within the above range, all of the metals contained in the precursor aqueous solution can be converted into a precipitate. In the step of generating a precipitate, the precursor aqueous solution may be dripped into the basic aqueous solution while stirring the basic aqueous solution to generate a precipitate.

[0042] In the above production process, the filtration and washing can be carried out by a general method. The drying temperature when drying the precipitate is preferably 40 to 200° C., more preferably 60 to 100° C. The drying time is preferably 3 to 48 hours, more preferably 12 to 24 hours. The drying of the precipitate is preferably carried out by placing the precipitate in a container and setting the pressure inside the container to 1 to 101.3 kPa, more preferably 3 to 10 kPa.

[0043] The calcination temperature when calcining the dried precipitate in air is preferably 200 to 700°C, more preferably 300 to 600°C, and even more preferably 400 to 500°C. The calcination time is preferably 1 to 10 hours, more preferably 2 to 7 hours, and even more preferably 4 to 6 hours. The temperature at which hydrogen reduction of the oxide obtained after calcination is performed is preferably 100 to 500°C, more preferably 150°C to 450°C, even more preferably 200 to 400°C, and particularly preferably 250 to 300°C. The time for hydrogen reduction is preferably 0.5 to 5 hours, more preferably 0.5 to 3 hours, and even more preferably 1 to 3 hours. When hydrogen reduction is performed, a mixed gas of hydrogen gas and nitrogen gas can be used as the hydrogen supply gas. The hydrogen gas content in the hydrogen supply gas is preferably 10 to 100 mol%, more preferably 50 to 100 mol%, and even more preferably 90 to 100 mol%.

[0044] The composition of the metal components of the catalyst thus obtained can be calculated, for example, by the method shown below. The mass of each metal precursor used as a raw material for the catalyst is measured. The filtrate obtained by filtration is subjected to inductively coupled plasma (ICP) measurement to determine the content of each metal contained in the filtrate. The composition of the catalyst is then calculated using the mass of each metal precursor used as a raw material and the content of each metal contained in the filtrate.

[0045] [Reaction process for producing gamma-butyrolactone] In the reaction step, it is preferable to vaporize the aqueous solution of the raw materials and bring the raw materials into contact with the catalyst. As the aqueous solution of the raw materials, it is preferable to use an aqueous solution containing 1 to 30% by mass of the raw materials, more preferably 5 to 25% by mass, and even more preferably 10 to 20% by mass. By vaporizing the aqueous solution containing 1 to 30% by mass of the raw materials and bringing the raw materials into contact with the catalyst, the reaction to produce gamma-butyrolactone can be further promoted. When an aqueous solution containing 30% or more of the raw material is used as the aqueous solution of the raw material, it is preferable to adjust the liquid hourly space velocity (LHSV) in terms of the raw material. For example, when an aqueous solution containing 30 to 50% of the raw material is used, in order to maintain the yield of gamma-butyrolactone, the liquid hourly space velocity (LHSV) in terms of the raw material is adjusted to 1.6 hr -1 It is preferable that the time is less than 0.4 hours. -1 The lower limit of the liquid hourly space velocity (LHSV) can be selected as necessary, for example, 0.1 hr -1 The number of times may be more than this, but is not limited to this.

[0046] In the reaction process, the raw material is vaporized and then heated to a temperature of 20,000 to 300,000 h -1 It is preferable to contact the material for 30,000 to 200,000 hours, and more preferably for 30,000 to 200,000 hours. -1 More preferably, it is 40,000 to 100,000 hours -1 GHSV is 20000hr -1 When the GHSV is 300,000 hr or more, the decrease in productivity of gamma-butyrolactone can be suppressed. -1If the temperature is equal to or lower than this, the reaction to produce gamma-butyrolactone proceeds sufficiently.

[0047] In the reaction step, the contact time (W / F) between the raw material and the catalyst can be selected arbitrarily, but is preferably 0.05 hr·g / mL or more, more preferably 0.1 hr·g / mL or more, and even more preferably 0.4 hr·g / mL or more. When W / F is 0.05 hr·g / mL or more, the reaction to produce gamma-butyrolactone proceeds sufficiently. The upper limit of the contact time (W / F) can be selected as necessary, and may be, for example, 3.2 hr·g / mL or less, but is not limited thereto. W indicates the weight of the catalyst, and F indicates the raw material supply rate.

[0048] In the reaction step, the raw material and the catalyst are contacted at a reaction temperature of more than 200°C to produce gamma-butyrolactone. In this embodiment, since the reaction temperature is more than 200°C, 2HTHF and the like during the reaction are present in a gas phase, and the reaction to produce gamma-butyrolactone is promoted, and gamma-butyrolactone can be produced in a higher yield. The reaction temperature is preferably 400°C or less, since the safety of the reaction to produce gamma-butyrolactone is further increased. The reaction temperature is more preferably 210 to 370°C, further preferably 230 to 360°C, and particularly preferably 260 to 350°C.

[0049] The gamma-butyrolactone obtained in the reaction step may be purified by a general method such as vacuum distillation, etc. The gamma-butyrolactone obtained in the reaction step can be preferably used as a raw material for N-methylpyrrolidone.

[0050] In the method for producing gamma-butyrolactone according to this embodiment, a raw material substance composed of 2HTHF or the like, and a catalyst containing an oxide of at least one metal element selected from the group consisting of zinc, zirconium, and aluminum and copper are brought into contact at a reaction temperature exceeding 200°C to have a reaction step of producing gamma-butyrolactone. 2HTHF or the like has good reactivity, and by bringing it into contact with the above catalyst at a reaction temperature exceeding 200°C, gamma-butyrolactone is rapidly produced. Moreover, 2HTHF or the like is subjected to a raw material production step using only one reaction of hydroformylating allyl alcohol using a mixed gas of carbon monoxide and hydrogen (H 2 ) before the reaction step, and can be easily produced. Therefore, the method for producing gamma-butyrolactone according to this embodiment is excellent in productivity.

[0051] <Method for producing N-methylpyrrolidone> The method for producing N-methylpyrrolidone (NMP) according to this embodiment includes a step of producing gamma-butyrolactone using the method for producing gamma-butyrolactone according to this embodiment, and a step of reacting the produced gamma-butyrolactone with monomethylamine. The step of reacting gamma-butyrolactone with monomethylamine can be, for example, a step of producing N-methylpyrrolidone by performing a liquid-phase reaction by putting gamma-butyrolactone, monomethylamine, and a solvent into a reaction vessel.

[0052] In this case, as the reaction vessel, a reaction vessel made of stainless steel can be preferably used. As the solvent, alcohols or water can be used, and preferably water. The molar ratio of monomethylamine to gamma-butyrolactone used as a raw material is preferably in the range of 1 to 10, more preferably in the range of 1 to 5, and even more preferably in the range of 1 to 1.5.

[0053] The reaction between gamma-butyrolactone and monomethylamine may be carried out in the air or in an inert gas atmosphere such as a nitrogen gas atmosphere or an argon atmosphere, and is preferably carried out in a nitrogen gas atmosphere. The reaction between gamma-butyrolactone and monomethylamine is preferably carried out at a temperature of 100 to 400° C., more preferably 150 to 350° C., and even more preferably 200 to 300° C. The reaction time is preferably 0.1 to 10 hours, more preferably 0.5 to 7 hours, and even more preferably 1 to 5 hours.

[0054] The N-methylpyrrolidone obtained in the step of reacting gamma-butyrolactone with monomethylamine may be purified by a general method such as reduced pressure distillation.

[0055] In the method for producing N-methylpyrrolidone of the present embodiment, gamma-butyrolactone is produced using the method for producing gamma-butyrolactone of the present embodiment, so that N-methylpyrrolidone can be produced efficiently. EXAMPLES

[0056] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0057] (1) Preparation of catalyst (a) CuZnZrAlOx catalyst (1) In a beaker, 5.03 g of copper nitrate (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.), 0.622 g of zinc nitrate (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.), 3.56 g of aluminum nitrate (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.), and 0.836 g of zirconium nitrate (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) were placed as metal precursors, and dissolved in 100 g of water to obtain a precursor aqueous solution. Next, while stirring the precursor aqueous solution, 3N sodium hydroxide aqueous solution was dropped into the precursor aqueous solution until the pH became 5, and a precipitate was obtained by a coprecipitation method. The precipitate was collected by filtration and washed with water. The washed precipitate was placed in a container, and dried under reduced pressure at a pressure of 6.3 kPa in an air atmosphere at a temperature of 80°C.

[0058] The dried precipitate was placed in an electric furnace and calcined in air at 500°C for 3 hours to obtain an oxide. 0.2 g of the obtained oxide was packed into a cylindrical reaction vessel (a reaction vessel of a fixed-bed gas phase reaction apparatus) with a diameter of 4.5 mm and a height of 10 mm. Before carrying out the reaction (3) below (production of GBL), hydrogen gas at 300°C was passed through the reaction vessel packed with the oxide at a flow rate of 30 mL / min for 1 hour to perform hydrogen reduction of copper oxide. Through the above steps, a catalyst layer of the prepared catalyst (a) was set in the reaction apparatus. The composition of the obtained catalyst was calculated by the above-mentioned method using the mass of the precursor of each metal used as a raw material and the content of each metal contained in the filtrate obtained after filtration. As a result, the catalyst composition was CuZnZrAlOx (molar ratio Cu:Zn:Zr:Al=10:0.2:1.9:5.5 (based on Zn=1, Cu:Zn:Zr:Al=46:1:8.6:25)).

[0059] (b) CuZnZrAlOx catalyst (2) A catalyst (b) having a composition of CuZnZrAlOx (molar ratio Cu:Zn:Zr:Al=10:1.0:1.5:4.5) was prepared in the same manner as in (a) above, except that a 3N aqueous solution of sodium hydroxide was added dropwise to the precursor aqueous solution until the pH reached 7.

[0060] (c) CuZrAlOx catalyst Catalyst (c) having a composition of CuZrAlOx (molar ratio of Cu:Zr:Al=10:1.5:4.5) was prepared in the same manner as in (a) above, except that the ratio of metal precursors was changed and the precursor aqueous solution was added dropwise to a 3N aqueous sodium hydroxide solution in a beaker while stirring it until the pH reached 7.

[0061] (d) CuZnAlOx catalyst By varying the ratio of metal precursors, catalyst (d) having the composition CuZnAlOx (molar ratio Cu:Zn:Al=10:1.0:4.5) was prepared according to the procedure of (c) above.

[0062] (e) CuZnZrAlOx catalyst (3) By varying the ratio of metal precursors, catalyst (e) having the composition CuZnZrAlOx (molar ratio Cu:Zn:Zr:Al=10:1.0:1.5:2.5) was prepared according to the procedure of (c) above.

[0063] (f) CuZnZrAlOx catalyst (4) By varying the ratio of metal precursors, catalyst (f) having the composition CuZnZrAlOx (molar ratio Cu:Zn:Zr:Al=15:1.0:1.5:4.5) was prepared according to the procedure of (c) above.

[0064] (g) CuZnZrAlCrOx catalyst (1) In a beaker, 5.03 g of copper nitrate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 0.622 g of zinc nitrate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 3.56 g of aluminum nitrate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 0.836 g of zirconium nitrate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and 0.836 g of chromium nitrate (manufactured by Kanto Chemical Industries, Ltd.) were placed as metal precursors, and dissolved in 106 g of water to obtain a precursor aqueous solution. Next, 30 g of a 3N aqueous solution of sodium hydroxide was placed in a beaker and stirred, and the precursor aqueous solution was dropped until the pH reached 7, and a precipitate was obtained by a coprecipitation method. The precipitate was collected by filtration and washed with water. The washed precipitate was placed in a container, and dried under reduced pressure at a pressure of 6.3 kPa in an air atmosphere at a temperature of 80°C.

[0065] The dried precipitate was placed in an electric furnace and calcined in air at 500°C for 3 hours to obtain an oxide. 0.2 g of the obtained oxide was filled into a cylindrical reaction vessel (a reaction vessel of a fixed-bed gas phase reaction apparatus) with a diameter of 4.5 mm and a height of 10 mm. Before carrying out the reaction (3) below (production of GBL), hydrogen gas at 300°C was passed through the reaction vessel filled with the oxide at a flow rate of 30 mL / min for 1 hour to perform hydrogen reduction of copper oxide. A catalyst layer of the prepared catalyst (g) was set in the reaction apparatus by the above steps. The composition of the obtained catalyst was calculated by the above-mentioned method using the mass of the precursor of each metal used as a raw material and the content of each metal contained in the filtrate obtained after filtration. As a result, the composition of the catalyst was CuZnZrAlCrOx (molar ratio Cu:Zn:Zr:Al:Cr=10:1.0:1.5:4.5:1.0).

[0066] (h) CuZnZrAlCrOx catalyst (2) By varying the ratio of metal precursors, catalyst (h) having the composition CuZnZrAlCrOx (molar ratio Cu:Zn:Zr:Al:Cr=10:1.0:1.5:4.5:2.0) was prepared according to the procedure of (g) above.

[0067] (2) Raw material production process (production of 2HTHF, etc.) In a 100 mL stainless steel autoclave reaction vessel, 1.89 g of allyl alcohol (AAL) and 30 g of toluene as a solvent were placed, and RhH(CO)(PPh 3 ) 3 The reaction vessel was filled with a mixture of carbon monoxide and hydrogen gas at a pressure of 2 MPa (partial pressure CO / H 2 = 1), and the reaction was carried out at a reaction temperature of 65°C for 3 hours while stirring the inside of the reaction vessel with a mechanical stirrer. After the reaction, the reaction liquid obtained was extracted with 30 g of water, and the target 2HTHF, etc. were obtained as an aqueous solution.

[0068] The obtained aqueous solution containing 2HTHF, etc. was analyzed by liquid chromatography to determine the conversion rate of allyl alcohol (AAL) and the yield of 2HTHF, etc. As a result, the conversion rate of AAL was 100%, and the yield of 2HTHF, etc. was 87.6%. The yield of 2HTHF, etc. is based on the total number of moles of 2HTHF and 4-HBA. This confirms that 2HTHF and other compounds can be easily produced with high conversion and yield using only one reaction, namely, hydroformylation of allyl alcohol using a mixed gas of carbon monoxide and hydrogen gas.

[0069] (3) Reaction process (production of gamma-butyrolactone (GBL)) The fixed-bed gas-phase reaction apparatus used was equipped with a vaporizer at the top of the reaction vessel, a carrier gas inlet and a raw material inlet at the top of the vaporizer, and a reaction liquid collection vessel (cooled) with a gas vent at the bottom of the reaction vessel.

[0070] (Examples 1 to 7, Comparative Example 1) Catalyst (a) was used in Examples 1 to 7 and Comparative Example 1. Using a fixed-bed gas phase reaction apparatus in which the catalyst layer obtained in (1) above was set in the reaction vessel, the aqueous solution containing 2HTHF and the like produced in (2) above at the concentrations shown in Table 1 was vaporized in a vaporizer, and supplied from the top of the reaction vessel under the conditions shown in Table 1 together with nitrogen gas as a carrier gas, and brought into contact with catalyst (a) under the conditions shown in Table 1 to produce gamma-butyrolactone.

[0071] Comparative Example 2 The catalyst (a) was also used in Comparative Example 2. Using a fixed-bed gas phase reactor in which the catalyst layer obtained in (1) above was set in the reaction vessel, an aqueous solution of 1,4-butanediol (1,4-BDO) having a concentration shown in Table 1 was vaporized in a vaporizer, and supplied from the top of the reaction vessel under the conditions shown in Table 1 together with nitrogen gas as a carrier gas, and brought into contact with the catalyst (a) under the conditions shown in Table 1 to produce gamma-butyrolactone.

[0072] Table 1 shows the raw materials, concentrations of 2HTHF etc. in the aqueous solution of 2HTHF etc. (concentration of 1,4-BDO in the aqueous 1,4-BDO solution in Comparative Example 2), reaction temperatures, flow rates (flow rates) of the aqueous solution of 2HTHF etc. (aqueous 1,4-BDO solution in Comparative Example 2), flow rate of nitrogen gas, liquid hourly space velocity (LHSV) and gas hourly space velocity (GHSV) calculated as raw materials used in Examples 1 to 7 and Comparative Examples 1 and 2. In addition, the gamma-butyrolactone obtained in Examples 1 to 7 and Comparative Examples 1 and 2 was analyzed by liquid chromatography to determine the conversion rate of the raw material (2HTHF, etc.) and the yield and selectivity of gamma-butyrolactone (GBL). The results are shown in Table 1.

[0073] [Table 1]

[0074] As shown in Table 1, in Examples 1 to 7, in which the raw material 2HTHF and the like were contacted with the catalyst (a) made of CuZnZrAlOx at a reaction temperature of over 200°C to produce gamma-butyrolactone, the raw material conversion rate, the yield and selectivity of gamma-butyrolactone (GBL) were high, and it was confirmed that the productivity was good. In addition, in Example 1 and Example 2, the reaction concentration and reaction temperature were the same, but the GHSV was different, but the raw material conversion rate and the yield of gamma-butyrolactone (GBL) were similar. -1 It was shown that even if the productivity was improved by carrying out the reaction at a high GHSV, good raw material conversion and gamma-butyrolactone (GBL) yield could be maintained.

[0075] In contrast, in Comparative Example 1, in which the raw material 2HTHF and the like were contacted with the catalyst (a) made of CuZnZrAlOx at a reaction temperature of 200°C to produce gamma-butyrolactone, the raw material conversion rate, the yield and the selectivity of gamma-butyrolactone (GBL) were low compared to Examples 1 to 7 in which the reaction temperature was over 200°C. In addition, in Comparative Example 2, in which 1,4-butanediol (1,4-BDO) was used as the raw material and catalyst (a) was used, the raw material conversion rate, the yield and the selectivity of gamma-butyrolactone (GBL) were lower than those in Examples 1 to 7. This is because the reactivity of 1,4-butanediol is lower than that of 2HTHF and the like.

[0076] (Example 8~ Example 10, Reference Example 11, Reference Example 12, Example 13, Example 14) The reaction was carried out in the same manner as in Example 1, except that the catalyst and reaction conditions shown in Table 2 were used. The results are shown in Table 2.

[0077] [Table 2]

[0078] From the comparison of the results of Examples 8 to 10, which differ only in the reaction temperature, it was confirmed that the raw material conversion rate, the yield and the selectivity of gamma-butyrolactone (GBL) were the highest in Example 9, in which the reaction temperature was 300°C. Reference Example 11, Reference Example 12, Example 13, Example From a comparison of the results of 14, it was confirmed that the raw material conversion rate, the yield and the selectivity of gamma-butyrolactone (GBL) were the highest in Example 9, in which the catalyst composition was CuZnZrAlOx (molar ratio Cu:Zn:Zr:Al=10:1.0:1.5:4.5).

[0079] (Examples 15 to 19, Comparative Example 3) The reaction was carried out in the same manner as in Example 1, except that the catalyst and reaction conditions shown in Table 3 were used. The results are shown in Table 3. Comparative Example 4 The reaction was carried out in the same manner as in Comparative Example 2, except that the catalyst and reaction conditions shown in Table 3 were used. The results are shown in Table 3.

[0080] [Table 3]

[0081] From a comparison of the results of Examples 15 and 16, or a comparison of the results of Examples 17 and 18, in which only the reaction temperature is different, it was confirmed that the raw material conversion rate, the yield and selectivity of gamma-butyrolactone (GBL) are improved when the reaction temperature is 300° C., compared to when the reaction temperature is 270° C. In addition, from a comparison of the results of Examples 15 and 17, in which only the type of catalyst is different, or a comparison of the results of Examples 16 and 18, it was confirmed that the raw material conversion rate, the yield and selectivity of gamma-butyrolactone (GBL) are improved when the catalyst composition is CuZnZrAlCrOx (molar ratio Cu:Zn:Zr:Al=10:1.0:1.5:4.5:1.0). In Comparative Example 3, where the reaction temperature was 200° C., the raw material conversion rate, the yield and the selectivity of gamma-butyrolactone (GBL) were low compared to Example 19, where the reaction temperature was over 200° C. In Comparative Example 4, where 1,4-butanediol (1,4-BDO) was used as the raw material, the raw material conversion rate, the yield and the selectivity of gamma-butyrolactone (GBL) were low.

[0082] (Examples 20 to 23) The reaction was carried out in the same manner as in Example 1, except that the catalyst and reaction conditions shown in Table 4 were used. In Examples 20 to 23, the flow rate (flow rate) of the aqueous solution of 2HTHF etc. and the flow rate of nitrogen gas were changed, and the ratio between them was fixed, while the contact time (W / F) between the raw material and the catalyst was changed. The results are shown in Table 4. (Examples 24 to 26) The reaction was carried out in the same manner as in Example 1, except that the catalyst and reaction conditions shown in Table 4 were used. In Examples 24 to 26, the concentration of 2HTHF etc. in the aqueous solution of 2HTHF etc. was set to 50 mass %, and the contact time (W / F) between the raw material and the catalyst was changed. The results are shown in Table 4. In preparing the catalysts used in Examples 24 to 26, hydrogen gas at 200° C. was passed through at a flow rate of 30 mL / min for 1 hour to carry out hydrogen reduction of copper oxide.

[0083] [Table 4]

[0084] From the results of Examples 20 to 23, it was confirmed that when the ratio of the flow rate (flow rate) of the aqueous solution of 2HTHF etc. to the flow rate of nitrogen gas was fixed, the yield of gamma-butyrolactone (GBL) improved as the contact time (W / F) between the raw material and the catalyst increased. Also, from the results of Examples 24 to 26, it was confirmed that the yield of gamma-butyrolactone (GBL) improved by increasing the contact time (W / F) between the raw material and the catalyst, even when the concentration of 2HTHF etc. was as high as 50 mass%.

[0085] (4) Manufacture of N-methylpyrrolidone (NMP) In a 100 mL stainless steel autoclave reaction vessel, 12.92 g of gamma-butyrolactone (GBL) obtained in Example 4, 12.89 g of 40% monomethylamine aqueous solution (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and 51.66 g of water as a solvent were placed. Then, in a nitrogen gas atmosphere, the reaction initiation pressure was set to 101.3 kPa, and the mixture was reacted at 240° C. for 3 hours with stirring to produce N-methylpyrrolidone.

[0086] The reaction solution containing the obtained N-methylpyrrolidone was analyzed by liquid chromatography to determine the conversion rate of gamma-butyrolactone (GBL) and the yield of N-methylpyrrolidone. As a result, the conversion rate of GBL was 98.4%, and the yield of NMP was 97.9%. From this, it was confirmed that N-methylpyrrolidone can be efficiently produced using the gamma-butyrolactone (GBL) obtained in Example 4. [Industrial Applicability]

[0087] The present invention provides a method for producing gamma-butyrolactone with good productivity. The method for producing gamma-butyrolactone of the present invention has good productivity and is therefore suitable as an industrial method for producing gamma-butyrolactone.

Claims

1. A method for producing gamma-butyrolactone, comprising a reaction step of contacting a raw material consisting of one or both of 2-hydroxytetrahydrofuran and 4-hydroxybutyraldehyde with a catalyst containing oxides of zinc, zirconium and aluminum, and metallic copper, at a reaction temperature of more than 200°C, to produce gamma-butyrolactone.

2. 2. The method for producing gamma-butyrolactone according to claim 1, wherein in the reaction step, an aqueous solution containing 1 to 30% by mass of the raw material is vaporized and brought into contact with the catalyst.

3. In the reaction step, the raw material is vaporized and heated to a gas hourly space velocity (GHSV) of 20,000 to 300,000 hr. －１ The method for producing gamma-butyrolactone according to claim 1 or 2, wherein the contact is carried out at a temperature of 100° C. or more.

4. The method for producing gamma-butyrolactone according to any one of claims 1 to 3, wherein in the reaction step, the raw material and the catalyst are contacted at a reaction temperature of 400°C or less.

5. The method for producing gamma-butyrolactone according to any one of claims 1 to 4, wherein the catalyst further contains an oxide of chromium.

6. Prior to the reaction step, Carbon monoxide and hydrogen (H ２ The method for producing gamma-butyrolactone according to any one of claims 1 to 5, further comprising a raw material production step of producing the raw material by hydroformylating allyl alcohol using a mixed gas of 1,2-dichlorophenyl ether and 1,2-dichlorophenyl ether.

7. 7. The method for producing gamma-butyrolactone according to claim 6, wherein in the raw material producing step, the allyl alcohol is hydroformylated in the presence of a catalyst comprising an organophosphorus compound ligand and a rhodium complex.

8. The method for producing gamma-butyrolactone according to claim 6 or 7, wherein the mixed gas has a molar ratio of hydrogen to carbon monoxide of 0.1 to 10.

9. The method for producing gamma-butyrolactone according to any one of claims 6 to 8, wherein the hydroformylation reaction of allyl alcohol is carried out at a reaction pressure of 0.1 to 10 MPa.

10. The method for producing gamma-butyrolactone according to any one of claims 6 to 9, wherein the hydroformylation reaction of allyl alcohol is carried out at a reaction temperature of 0 to 150°C.

11. The method for producing gamma-butyrolactone according to any one of claims 1 to 10, wherein the catalyst contains 0.01 to 0.2 moles of zinc, 0.01 to 1 moles of zirconium, and 0.05 to 3 moles of aluminum per mole of copper.

12. The method for producing gamma-butyrolactone according to any one of claims 5 to 10, wherein the catalyst contains 0.01 to 0.5 moles of zinc, 0.01 to 1 moles of zirconium, 0.05 to 3 moles of aluminum, and 0.01 to 0.3 moles of chromium per mole of copper.

13. A step of producing gamma-butyrolactone using the method for producing gamma-butyrolactone according to any one of claims 1 to 12; and reacting the produced gamma-butyrolactone with monomethylamine.

14. A catalyst for producing gamma-butyrolactone, which is used in the production of gamma-butyrolactone from raw materials consisting of one or both of 2-hydroxytetrahydrofuran and 4-hydroxybutyraldehyde, and which contains oxides of zinc, zirconium and aluminum, as well as metallic copper.

15. The catalyst for producing gamma-butyrolactone according to claim 14, wherein the catalyst further contains an oxide of chromium.

16. The catalyst for producing gamma-butyrolactone according to claim 14 or 15, wherein the catalyst contains 0.01 to 0.2 moles of zinc, 0.01 to 1 moles of zirconium, and 0.05 to 3 moles of aluminum per mole of copper.

17. The catalyst for producing gamma-butyrolactone according to claim 15, wherein the catalyst contains 0.01 to 0.5 moles of zinc, 0.01 to 1 moles of zirconium, 0.05 to 3 moles of aluminum, and 0.01 to 0.3 moles of chromium per mole of copper.

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