JP4566332B2 - Process for producing 3-methyltetrahydrofuran and its intermediate - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a process for producing 3-methyltetrahydrofuran, and a process for producing 3-methyldihydrofuran, particularly 3-methyl-4,5-dihydrofuran and 3-methyl-2,5-dihydrofuran, which are intermediates thereof. . The 3-methyltetrahydrofuran obtained in the present invention is useful, for example, as a raw material for polyether polyol, which is a component of thermoplastic polyurethane, and as a solvent. On the other hand, 3-methyldihydrofuran obtained by the present invention is useful as a raw material for chemicals such as pharmaceuticals and agricultural chemicals.
[0002]
[Prior art]
As a conventional method for producing 3-methyltetrahydrofuran, (a) a method in which 2-methyl-1,4-butanediol is subjected to dehydration cyclization [Ind. Eng. Chem. Res., Vol. 33] 444-447 (1994)], (b) a method in which methylsuccinic acid is hydrogenated using isopropanol as a hydrogen source in the presence of a hydrous zirconium oxide catalyst [Bullin of Chemical Society Japan (Bull. Chem. Soc. Jpn. ), 65, pp. 262-266 (1992)], (c) a method of hydroformylating methallyl alcohol, hydrogenating the resulting formyl form, and then dehydrating and cyclizing [Journal of Practicing Chemie (J .Prakt.Chem.), No. 31 4, 840-850 (1972)], (d) a method of hydrogenating 3-methyl-3,4-epoxybutan-1-ol in an acidic aqueous solution (see US Pat. No. 3,956,318). Are known.
[0003]
On the other hand, as a method for producing 3-methyl-4,5-dihydrofuran or 3-methyl-2,5-dihydrofuran, (e) an alcohol compound obtained by hydroformylating methacrolein diethyl acetal and reducing an aldehyde group A method of obtaining 3-methyl-4,5-dihydrofuran by subjecting to a deethanol reaction after cyclization (see Journal of Organic Chemistry (J. Org. Chem.), 37, 1835 (1972)) (F) a method of isomerizing 3-methyl-3,4-epoxy-1-butene in the presence of a higher tertiary amine and a zinc oxide catalyst to obtain 3-methyl-2,5-dihydrofuran (international); Publication see Japanese Patent WO91 / 13882); iodide and (g) isoprene oxide of iron acetylacetonate (Fe (acac) ₃₎ Isomerization in the presence of silicon to give 3-methyl-2,5-dihydrofuran (see US Pat. No. 3,932,468); (h) reaction of hydroxyacetone with vinyltriphenylphosphonium bromide followed by cyclization Thus, a method for obtaining 3-methyl-2,5-dihydrofuran (see Journal of Organic Chemistry (J. Org. Chem.), Vol. 33, page 583 (1968)) is known.
[0004]
[Problems to be solved by the invention]
However, in the method (a), it is difficult to obtain 2-methyl-1,4-butanediol as a raw material at a low cost and stably. In the method (b), the preparation of hydrous zirconium oxide used as a catalyst is complicated, and an equivalent amount of acetone is by-produced from isopropanol used as a hydrogen source. In the method (c), the rhodium compound used as a catalyst for the hydroformylation reaction is expensive, and the raw material methallyl alcohol is not industrially produced and is difficult to obtain easily and inexpensively. In the method (d), 3-methyl-3,4-epoxybutan-1-ol is not industrially produced and cannot be easily and inexpensively obtained. Hydrolysis is inevitable, and there is a problem that a triol body in which the epoxy ring is opened is by-produced. Therefore, these methods cannot be said to be industrially advantageous production methods for 3-methyltetrahydrofuran.
[0005]
In the method (e), unstable methacrolein must be acetalized, and a hydroformylation reaction must be performed using an expensive rhodium catalyst, and the number of steps is large. In the method (f), it is difficult to prepare a catalyst. In the method (g), it is necessary to use highly corrosive hydrogen iodide. In the method (h), since vinyltriphenylphosphonium bromide used in an equimolar amount with respect to hydroxyacetone is prepared, there is a problem that a large amount of expensive triphenylphosphine must be used. Therefore, these methods cannot be said to be industrially advantageous production methods for 3-methyldihydrofuran.
Therefore, an object of the present invention is to provide a method by which 3-methyltetrahydrofuran and 3-methyldihydrofuran can be conveniently and conveniently produced in good yields.
[0006]
[Means for Solving the Problems]
According to the present invention, the above object is
(1) 3-hydroxy-3-methyltetrahydrofuran is dehydrated in the presence of an acidic substance to obtain 3-methyldihydrofuran, and the resulting 3-methyldihydrofuran is reacted with hydrogen in the presence of a hydrogenation catalyst. A process for producing 3-methyltetrahydrofuran,
(2) A process for producing 3-methyltetrahydrofuran characterized by reacting 3-methyldihydrofuran with hydrogen in the presence of a hydrogenation catalyst, and (3) presence of an acidic substance of 3-hydroxy-3-methyltetrahydrofuran This is achieved by providing a process for producing 3-methyldihydrofuran, which is characterized in that dehydration reaction is performed below.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The production method of the present invention will be described in detail for each step.
(1) Step of dehydrating 3-hydroxy-3-methyltetrahydrofuran in the presence of an acidic substance to obtain 3-methyldihydrofuran
Examples of the acidic substance include inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, polyphosphoric acid, sodium hydrogen sulfate, potassium hydrogen sulfate, potassium dihydrogen phosphate, sodium hydrogen sulfite, potassium hydrogen sulfite, etc .; methanesulfonic acid, benzene Sulfonic acids such as sulfonic acid and toluenesulfonic acid; Carboxylic acids such as acetic acid, propionic acid, benzoic acid and terephthalic acid; Heteropolyacids such as phosphotungstic acid, phosphomolybdic acid, silicotungstic acid and silicomolybdic acid; silica, alumina, Examples thereof include solid acids such as silica-alumina, titania, silica-titania and niobium oxide; acidic ion exchange resins such as sulfonic acid ion exchange resins and carboxylic acid ion exchange resins.
These acidic substances may be used alone or in combination of two or more. In addition, the above-mentioned homogeneous acids such as inorganic acids or salts thereof, sulfonic acids, carboxylic acids, and heteropoly acids can be adsorbed and supported on activated carbon, alumina, silica, etc., and used in the same manner as solid acids. The amount of the acidic substance to be used is not particularly limited. However, when a homogeneous acid such as an inorganic acid or a salt thereof, a sulfonic acid, a carboxylic acid, or a heteropoly acid is used as the acidic substance, usually 1 mol of 3-hydroxy-3-methyltetrahydrofuran. Is preferably in the range of 0.001 to 50 mol%, more preferably in the range of 0.01 to 10 mol% from the viewpoint of reaction efficiency and economy. In addition, when an acidic substance using a solid acid, an acidic ion exchange resin, or a homogeneous acid adsorbed and supported on activated carbon, alumina, silica or the like is used, the amount used is usually 3-hydroxy-3-methyltetrahydrofuran. It is preferable that it is 0.01 to 10 weight% of range.
[0009]
The reaction can be carried out in the presence or absence of a solvent. Solvents that can be used are not particularly limited as long as they do not adversely affect the reaction, for example, aliphatic hydrocarbons such as hexane, heptane, octane, nonane, decane, and cyclohexane; aromatic hydrocarbons such as benzene, toluene, xylene, and mesitylene; Halogenated hydrocarbons such as dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane, chlorobenzene and the like can be mentioned. When a solvent is used, the amount used is not particularly limited, but it is usually preferably in the range of 0.01 to 10 times by weight with respect to 3-hydroxy-3-methyltetrahydrofuran, and the reaction proceeds smoothly and volume. From the viewpoint of efficiency, economy, etc., the range of 0.1 to 2 times by weight is more preferable.
[0010]
The reaction temperature is preferably in the range of 40 to 200 ° C, more preferably in the range of 60 to 140 ° C. When the reaction temperature is lower than 40 ° C, the progress of the reaction tends to be extremely slow. On the other hand, when the reaction temperature is higher than 200 ° C, the product 3-methyldihydrofuran tends to be highly boiling. The rate goes down.
[0011]
The reaction can be carried out, for example, by mixing an acidic substance, 3-hydroxy-3-methyltetrahydrofuran and, if necessary, a solvent and stirring at a predetermined temperature. The reaction can be carried out either batchwise or continuously, but is preferably carried out continuously from the viewpoint of product stability and productivity. When the reaction is carried out continuously, the product 3-methyldihydrofuran has a boiling point lower than that of 3-hydroxy-3-methyltetrahydrofuran, which is a raw material. Therefore, as a reaction mode, an acidic substance is dissolved or suspended in a solvent. A method in which 3-hydroxy-3-methyltetrahydrofuran is continuously added to this solution while stirring at a predetermined temperature and the product is allowed to react while continuously distilling off the product is preferred. In this method, it is preferable to use a solvent having a boiling point higher than that of 3-hydroxy-3-methyltetrahydrofuran.
[0012]
The resulting 3-methyldihydrofuran, ie, 3-methyl-4,5-dihydrofuran or 3-methyl-2,5-dihydrofuran, can be further increased in purity by a conventional purification method such as distillation. .
[0013]
(2) Step of obtaining 3-methyltetrahydrofuran by reacting 3-methyldihydrofuran with hydrogen in the presence of a hydrogenation catalyst Examples of 3-methyldihydrofuran include 3-methyl-4,5-dihydrofuran, 3- Methyl-2,5-dihydrofuran or a mixture thereof can be used.
[0014]
Examples of the hydrogenation catalyst include noble metal oxides such as palladium oxide and platinum oxide; noble metals such as palladium, ruthenium, rhodium and platinum supported on activated carbon, alumina, silica, silica-alumina, silica-titania, acidic ion exchange resin, and the like. Catalysts; nickel catalysts such as stabilized nickel, Raney nickel, nickel diatomaceous earth; copper catalysts such as Raney copper, copper chromite, and copper zinc. These hydrogenation catalysts may be used individually by 1 type, or may mix and use 2 or more types. Although there is no restriction | limiting in particular in the usage-amount of a hydrogenation catalyst, Usually, it is preferable that it is the range of 0.001 to 100 weight% with respect to 3-methyldihydrofuran, and it is 0 from a viewpoint of operativity, reactivity, and economical efficiency. The amount is more preferably 0.01 to 50% by weight, and further preferably 0.05 to 10% by weight.
[0015]
There is no particular restriction on the amount of hydrogen used, but it is usually preferably in the range of normal pressure to 20 MPa. From the viewpoint of operability, safety, and smooth progress of the reaction, it is in the range of normal pressure to 5 MPa. Is more preferable, and the range of normal pressure to 2 MPa is even more preferable.
[0016]
The reaction can be carried out in the presence or absence of a solvent. Solvents that can be used are not particularly limited as long as they do not adversely affect the reaction. For example, aliphatic hydrocarbons such as pentane, hexane, heptane, octane, nonane, decane, cyclohexane, and cyclooctane; benzene, toluene, xylene, mesitylene, etc. Aromatic alcohols such as methanol, ethanol, propanol, isopropanol, butanol and octanol; ethers such as diethyl ether, diisopropyl ether and tetrahydrofuran. When a solvent is used, the amount used is not particularly limited, but it is usually preferably in the range of 0.01 to 100 times by weight with respect to 3-methyldihydrofuran, and the reaction proceeds smoothly, operability, volume. From the viewpoint of efficiency and the like, the range of 0.1 to 10 times by weight is more preferable.
[0017]
The reaction temperature is preferably in the range of 0 to 200 ° C, more preferably in the range of 20 to 150 ° C, and still more preferably in the range of 60 to 150 ° C from the viewpoints of operability, safety, and smooth progress of the reaction.
[0018]
The reaction is preferably carried out, for example, by adding 3-methyldihydrofuran, a hydrogenation catalyst and, if necessary, a solvent to the reactor and sealing, then pressurizing the system with hydrogen and stirring at a predetermined temperature. Further, the reaction can be carried out by either a batch method or a continuous method.
[0019]
The 3-methyltetrahydrofuran thus obtained can be isolated and purified by a method similar to the method used for ordinary organic compound isolation and purification means. For example, the obtained reaction solution is filtered, washed with water as necessary, and then distilled.
[0020]
In addition, 3-hydroxy-3-methyltetrahydrofuran used as a raw material in the method of the present invention is obtained by converting 3-methyl-3-buten-1-ol to TS-1 (tetraethylorthosilicate (Si (OEt) ₄ ): tetraethylorthotitanate). Titano obtained by hydrothermal synthesis of a mixture of (Ti (OEt) ₄ ) = 40: 1 (molar ratio) at 175 ° C. in the presence of a catalytic amount of tetrapropylammonium hydroxide (Pr ₄ NOH) It can be easily produced by reacting with hydrogen peroxide in the presence of zeolite such as titanosilicate represented by silicate (see Japanese Patent Application No. 11-142631). Further, 3-methyl-3-buten-1-ol can be easily synthesized, for example, by thermally condensing formaldehyde and isobutene (Angew Cheme International Edition in English (Angew. Chem. Int. Ed. Engl. ), Vol. 8, 556 (1969)).
[0021]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited at all by these Examples.
[0022]
Example 1
In a 200 ml three-necked flask equipped with a thermometer, a reflux tube and a magnetic stirrer, 50 g (0.48 mol) of 3-hydroxy-3-methyltetrahydrofuran, 50 g of mesitylene and 1.0 g of acidic ion exchange resin (Amberlyst 15, Made by Organo Co., Ltd.), heated to 120 ° C. with stirring, and allowed to react for 3 hours while distilling the low-boiling products produced. The amount of distillate was 54.2 g. The composition of the distillate was gas chromatography (column: G-300, 50 m (manufactured by Chemicals Research Association); analysis conditions: injection temperature 240 ° C., detector temperature 220 ° C., column temperature: 70 ° C., carrier gas: helium 40 ml / min, hydrogen 50 kPa, Air 50 kPa) contained 38.3 g of 3-methyldihydrofurans (reaction yield 95.0%, 3-methyl-2,5-dihydrofuran: 3-methyl-4 , 5-dihydrofuran = 89: 11).
[0023]
Example 2
To a 100 ml three-necked flask equipped with a thermometer, a reflux tube, and a magnetic stirrer, 20 g (0.19 mol) of 3-hydroxy-3-methyltetrahydrofuran, 20 g of mesitylene, and 0.01 g of potassium hydrogen sulfate were added and stirred. The mixture was heated to 120 ° C. and reacted for 4.2 hours while distilling out the low-boiling products produced. The amount of distillate was 22.1 g. When the distillate composition was analyzed by gas chromatography under the same analysis conditions as in Example 1, it contained 15.0 g of 3-methyldihydrofurans (reaction yield 92.8%, 3-methyl-2, 5-dihydrofuran: 3-methyl-4,5-dihydrofuran = 90: 10).
[0024]
Example 3
A 100 ml three-necked flask equipped with a thermometer and a reflux tube magnetic stirrer was charged with 20 g (0.19 mol) of 3-hydroxy-3-methyltetrahydrofuran, 20 g of decane and 0.01 g of sulfuric acid, and the mixture was stirred at 130 ° C. The mixture was heated and allowed to react for 1.2 hours while distilling the low-boiling product produced. The amount of distillate was 24.3 g. The distillate composition was analyzed by gas chromatography under the same analysis conditions as in Example 1. As a result, it contained 14.2 g of 3-methyldihydrofurans (reaction yield: 88.8%, 3-methyl-2, 5-dihydrofuran: 3-methyl-4,5-dihydrofuran = 87: 13).
[0025]
Example 4
3-methyldihydrofuran (3-methyl-2) obtained by the method of Example 2 in an autoclave (material: Hastelloy C) having a capacity of 100 ml equipped with a magnetic stirrer, pressure gauge, needle valve, gas inlet and sampling port. , 5-dihydrofuran: mixture of 3-methyl-4,5-dihydrofuran = 90: 10), 15 g of isopropanol and 0.15 g of 10% palladium-carbon (manufactured by Degussa; 5% E106NN / W) are sealed. did. The inside of the autoclave was replaced with nitrogen, then replaced with hydrogen, and then pressurized to 1 MPa with hydrogen. The temperature was raised to 80 ° C., the pressure in the reactor was maintained at 1 MPa, and the mixture was stirred for 6 hours while continuously supplying hydrogen consumed in the reaction. After completion of the reaction, the system was cooled to room temperature, the inside of the system was purged with nitrogen, the reaction solution was taken out and a part thereof was analyzed by gas chromatography (column used: PEG-HT, column length 3 m × column diameter 4 mm; analysis conditions: Injection temperature 220 ° C., detector temperature 240 ° C., column temperature: constant 70 ° C., carrier gas: helium 40 ml / min, H ₂ 50 kPa, Air 50 kPa). The selectivity was 97.2%. The resulting reaction solution was distilled under normal pressure to obtain 13.2 g of 3-methyltetrahydrofuran (purity 99.8%).
[0026]
【The invention's effect】
3-Methyltetrahydrofuran and 3-methyldihydrofuran can be conveniently produced in a good yield and industrially advantageously.

Claims (3)

Dehydration reaction of 3-hydroxy-3-methyltetrahydrofuran in the presence of an acidic substance to obtain 3-methyldihydrofuran, and the resulting 3-methyldihydrofuran is reacted with hydrogen in the presence of a hydrogenation catalyst A process for producing 3-methyltetrahydrofuran. A process for producing 3-methyltetrahydrofuran, comprising reacting 3-methyldihydrofuran with hydrogen in the presence of a hydrogenation catalyst. A process for producing 3-methyldihydrofuran, comprising dehydrating 3-hydroxy-3-methyltetrahydrofuran in the presence of an acidic substance.