JP2001226366A - Method for producing 3-methyltetrahydrofuran and intermediate thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for simply producing 3-methyltetrahydrofuran and 3-methyldihydrofuran in high yield with industrial advantage. SOLUTION: 3-Hydroxy-3-methyltetrahydrofuran is dehydrated in the presence of an acidic substance to for 3-methyldihydrofuran and the resultant 3- methyldihydrofuran is characteristically hydrogenated in the presence of a hydrogenation catalyst to produce the objective 3-methyltetrahydrofuran.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing 3-methyltetrahydrofuran and its intermediate, 3
-Methyldihydrofuran, in particular 3-methyl-4,5-dihydrofuran and 3-methyl-2,5-dihydrofuran. The 3-methyltetrahydrofuran obtained in the present invention is useful, for example, as a raw material of a polyether polyol which is a component of a thermoplastic polyurethane and as a solvent. On the other hand, 3-methyldihydrofuran obtained in the present invention is useful as a raw material for chemicals such as medicines and agricultural chemicals.

[0002]

2. Description of the Related Art Conventional methods for producing 3-methyltetrahydrofuran include (a) a method of dehydrating and cyclizing 2-methyl-1,4-butanediol [Industrial Engineering Chemistry Research (Ind. E);
ng. Chem. Res. 33), 444-44
7 (1994)], (b) a method of hydrogenating methyl succinic acid in the presence of a hydrous zirconium catalyst using isopropanol as a hydrogen source [Bulittin of Chemical Society Japan (Bull. Chem.
Soc. Jpn. ), Vol. 65, pp. 262-266 (1
992)], (c) hydroformylation of methallyl alcohol, hydrogenation of the resulting formyl form, followed by dehydration cyclization [Journal of Practitioner]
Chemie (J. Prakt. Chem.), Vol.
840-850 (1972)], and (d) 3-methyl-3,4-epoxybutane-1- in an acidic aqueous solution.
A method for hydrogenating all (see US Pat. No. 3,956,318) is known.

On the other hand, as a process for producing 3-methyl-4,5-dihydrofuran or 3-methyl-2,5-dihydrofuran, (e) hydroformylation of methacrolein diethyl acetal is carried out to reduce an aldehyde group. A method for obtaining 3-methyl-4,5-dihydrofuran by cyclizing an alcohol compound and then subjecting it to a deethanolation reaction (Journal of Organic Chemistry (J. Orr)
g. Chem. 37), p. 1835 (1972).
Year))); (f) 3-methyl-3,4-epoxy-1
A method for isomerizing butene in the presence of a higher tertiary amine and a zinc oxide catalyst to obtain 3-methyl-2,5-dihydrofuran (see WO 91/13882); (g) isoprene oxide A method of obtaining 3-methyl-2,5-dihydrofuran by isomerization in the presence of iron acetylacetonate (Fe (acac) ₃ ) and hydrogen iodide (see U.S. Pat. No. 3,932,468); (h) hydroxyacetone And vinyltriphenylphosphonium bromide, followed by cyclization to give 3-methyl-2,
Method for obtaining 5-dihydrofuran (Journal of Organic Chemistry (J. Org. Che)
m. ), Vol. 33, p. 583 (1968)) and the like.

[0004]

However, in the method (a), it is difficult to obtain 2-methyl-1,4-butanediol as a raw material at low cost and in a stable manner.
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), a rhodium compound used as a catalyst for the hydroformylation reaction is expensive, and methallyl alcohol as a raw material is not industrially produced, so that it is difficult to obtain it easily and inexpensively. In the method (d), 3-methyl-
3,4-Epoxybutan-1-ol is not manufactured industrially, cannot be obtained easily and inexpensively, and under the condition of reacting in an acidic aqueous solution, hydrolysis of the raw material is unavoidable, and the epoxy ring is opened. There is a problem that a cyclic triol is formed as a by-product. Therefore, these methods cannot be said to be industrially advantageous methods for producing 3-methyltetrahydrofuran.

In the method (e), the unstable methacrolein is acetalized, and the hydroformylation reaction must be carried out using an expensive rhodium catalyst, and the number of steps is large. In the method (f), preparation of the catalyst is difficult. In the method (g), it is necessary to use highly corrosive hydrogen iodide. In the method (h), since vinyltriphenylphosphonium bromide is used in an equimolar amount to hydroxyacetone, there is a problem that a large amount of expensive triphenylphosphine must be used. Therefore, these methods cannot be said to be industrially advantageous methods for producing 3-methyldihydrofuran. Accordingly, an object of the present invention is to provide a method capable of producing 3-methyltetrahydrofuran and 3-methyldihydrofuran easily and in a high yield in an industrially advantageous manner.

[0006]

According to the present invention, the above object has been achieved by obtaining 3-methyldihydrofuran by dehydrating 3-hydroxy-3-methyltetrahydrofuran in the presence of an acidic substance. Reacting 3-methyldihydrofuran with hydrogen in the presence of a hydrogenation catalyst.
Method for producing methyltetrahydrofuran, 3-methyldihydrofuran in the presence of a hydrogenation catalyst,
A method for producing 3-methyltetrahydrofuran, characterized by reacting with hydrogen; and a method of dehydrating 3-hydroxy-3-methyltetrahydrofuran in the presence of an acidic substance,
This is achieved by providing a method for producing methyldihydrofuran.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The manufacturing method of the present invention will be described in detail for each step. (1) Step of subjecting 3-hydroxy-3-methyltetrahydrofuran to a dehydration reaction in the presence of an acidic substance to obtain 3-methyldihydrofuran

Examples of the acidic substance include hydrochloric acid, sulfuric acid, phosphoric acid, polyphosphoric acid, sodium hydrogen sulfate, potassium hydrogen sulfate, potassium dihydrogen phosphate, sodium hydrogen sulfite,
Inorganic acids such as potassium bisulfite or salts thereof; sulfonic acids such as methanesulfonic acid, benzenesulfonic acid, and toluenesulfonic acid; carboxylic acids such as acetic acid, propionic acid, benzoic acid, and terephthalic acid; phosphotungstic acid, phosphomolybdic acid; Heteropoly acids such as silicotungstic acid and silicomolybdic acid; solid acids such as silica, alumina, silica-alumina, titania, silica-titania, and niobium oxide; acidic ions such as sulfonic acid-based ion exchange resins and carboxylic acid-based ion exchange resins Exchange resin and the like. Even if these acidic substances are used alone,
Further, two or more kinds may be used in combination. 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, or the like, and used in the same manner as solid acids. The amount of the acidic substance used is not particularly limited, but when an inorganic acid or a salt thereof, a sulfonic acid, a carboxylic acid, or a homogeneous acid such as a heteropoly acid is used as the acidic substance,
Usually 3-hydroxy-3-methyltetrahydrofuran 1
It is preferably in the range of 0.001 to 50 mol% based on mol, and from the viewpoint of reaction efficiency and economy, it is preferably 0.01 to 1 mol%.
More preferably, it is in the range of 0 mol%. When 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 as the acidic substance, the amount of the acid used is usually 3-hydroxy-3-methyltetrahydrofuran. 0.01 to 1
It is preferably in the range of 0% by weight.

[0009] The reaction can be carried out in the presence or absence of a solvent. The solvent that can be used is not particularly limited as long as it does not adversely affect the reaction, for example, hexane,
Aliphatic hydrocarbons such as heptane, octane, nonane, decane and cyclohexane; aromatic hydrocarbons such as benzene, toluene, xylene and mesitylene; halogenated carbons such as dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane and chlorobenzene Hydrogen and the like. When a solvent is used, its use amount is not particularly limited, but it is usually preferably in the range of 0.01 to 10 times by weight based on 3-hydroxy-3-methyltetrahydrofuran. From the viewpoints of efficiency, economy and the like, the ratio is more preferably 0.1 to 2 times by weight.

[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. The rate is lower.

The reaction can be carried out, for example, by mixing an acidic substance, 3-hydroxy-3-methyltetrahydrofuran and, if necessary, a solvent and stirring the mixture at a predetermined temperature.
In addition, the reaction can be performed in a batch system or a continuous system, but is preferably performed in a continuous system from the viewpoints of product stability and productivity. In the case of performing the reaction in a continuous manner, 3-methyldihydrofuran as a product has a lower boiling point than 3-hydroxy-3-methyltetrahydrofuran as a raw material. Therefore, as a reaction mode, an acidic substance is dissolved or suspended in a solvent. A method is preferred in which 3-hydroxy-3-methyltetrahydrofuran is continuously added to this solution while stirring at a predetermined temperature, and the reaction is carried out while continuously distilling off the product. In this method, 3-hydroxy-3-
It is preferable to use a solvent having a higher boiling point than methyltetrahydrofuran.

The obtained 3-methyldihydrofuran, ie, 3-methyl-4,5-dihydrofuran or 3-methyl-2,5-dihydrofuran, is further purified by a conventional purification method such as distillation. be able to.

(2) Step of reacting 3-methyldihydrofuran with hydrogen in the presence of a hydrogenation catalyst to obtain 3-methyltetrahydrofuran Examples of the 3-methyldihydrofuran include 3-methyl-4,5-dihydrofuran , 3-methyl-2,5-dihydrofuran, or mixtures thereof.

Examples of the hydrogenation catalyst include noble metal oxides such as palladium oxide and platinum oxide; activated carbon, alumina,
Silica, silica-alumina, silica-titania, palladium supported on an acidic ion exchange resin, ruthenium,
Noble metal catalysts such as rhodium and platinum; nickel catalysts such as stabilized nickel, Raney nickel and nickel diatomaceous earth; and copper catalysts such as Raney copper, copper chromite and copper zinc. One of these hydrogenation catalysts may be used alone, or two or more thereof may be used in combination. Although there is no particular limitation on the amount of the hydrogenation catalyst, it is usually preferably in the range of 0.001 to 100% by weight based on 3-methyldihydrofuran, and is 0 from the viewpoint of operability, reactivity and economy. 0.01 to 50% by weight, more preferably 0.1 to 50% by weight.
More preferably, it is in the range of 0.05 to 10% by weight.

Although the amount of hydrogen used is not particularly limited, it is usually preferably in the range of normal pressure to 20 MPa. From the viewpoints of operability, safety, smooth progress of the reaction, etc.
The pressure is more preferably in the range of Pa, and further preferably in the range of normal pressure to 2 MPa.

[0016] The reaction can be carried out in the presence or absence of a solvent. The solvent that can be used is not particularly limited as long as it does not adversely affect the reaction, for example, pentane, hexane, heptane, octane, nonane, decane,
Aliphatic hydrocarbons such as cyclohexane and cyclooctane; aromatic hydrocarbons such as benzene, toluene, xylene and mesitylene; alcohols such as methanol, ethanol, propanol, isopropanol, butanol and octanol; ethers such as diethyl ether, diisopropyl ether and tetrahydrofuran And the like. When a solvent is used, its use amount is not particularly limited, but is usually 0.01 to 3 methyldihydrofuran.
It is preferably in the range of from 100 to 100 times by weight.
More preferably, it is in the range of 0 times by weight.

The reaction temperature is preferably in the range of 0 to 200 ° C., and more preferably in the range of 20 to 150 ° C., preferably 60 to 15 from the viewpoints of operability, safety, and smooth progress of the reaction.
A range of 0 ° C. is more preferred.

The reaction is carried out, for example, by putting 3-methyldihydrofuran, a hydrogenation catalyst and, if necessary, a solvent into a reactor, sealing the system, pressurizing the system with hydrogen, and stirring at a predetermined temperature. preferable. Further, the reaction can be carried out by either a batch method or a continuous method.

The thus obtained 3-methyltetrahydrofuran 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 if necessary, and then distilled.

The 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.
(Tetraethyl orthosilicate (Si (OE
t) ₄ ): tetraethyl orthotitanate (Ti (OE
t) ₄ ) = 40: 1 (molar ratio) with a catalytic amount of tetrapropylammonium hydroxide (Pr ₄ NO
H) in the presence of zeolite such as titanosilicate represented by hydrothermal synthesis at 175 ° C. in the co-presence of H) to react with hydrogen peroxide for easy production. Can be done (Japanese Patent Application No. 1
1-114231). Also, 3-methyl-3-buten-1-ol can be easily synthesized, for example, by thermally condensing formaldehyde and isobutene (Angevante Hemy International Edition in English (Angew. Che).
m. Int. Ed. Engl. ), Vol. 8, p. 556 (1969)).

[0021]

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

Example 1 A 200 ml three-necked flask equipped with a thermometer, a reflux tube and a magnetic stirrer was charged with 50 g of 3-hydroxy-3-methyltetrahydrofuran (0.48 m
ol), 50 g of mesitylene and 1.0 g of acidic ion exchange resin (Amberlyst 15, manufactured by Organo Corporation)
Was heated to 120 ° C. while stirring, and reacted for 3 hours while distilling out the low-boiling substances generated. The amount of the distillate was 54.2 g. The composition of the distillate was determined by gas chromatography (column: G-300, 50 m (manufactured by Japan Chemical Inspection Association); analysis conditions: injection temperature 240 ° C., detector temperature 220 ° C., column temperature: 70 ° C., carrier gas: helium 40 ml / min, 50kP hydrogen
a, Air 50 kPa) and found to contain 38.3 g of 3-methyldihydrofurans (reaction yield 9).
5.0%, 3-methyl-2,5-dihydrofuran: 3-
Methyl-4,5-dihydrofuran = 89:11).

Example 2 In a 100 ml three-necked flask equipped with a thermometer, a reflux tube and a magnetic stirrer, 20 g of 3-hydroxy-3-methyltetrahydrofuran (0.19 m
ol), 20 g of mesitylene and potassium hydrogen sulfate 0.1 g.
Then, the mixture was heated to 120 ° C. while stirring, and reacted for 4.2 hours while distilling out the low-boiling substances generated. The amount of the distillate was 22.1 g. The composition of the distillate was analyzed by gas chromatography under the same analysis conditions as in Example 1, and found to contain 15.0 g of 3-methyldihydrofurans (reaction yield: 92.8%, 3-methyl-2, 5-dihydrofuran: 3-methyl-4,5-dihydrofuran =
90:10).

Example 3 3-Hydroxy-3 was placed in a 100 ml three-necked flask equipped with a thermometer and a reflux tube magnetic stirrer.
-Methyl tetrahydrofuran 20 g (0.19 mo
l), 20 g of decane and 0.01 g of sulfuric acid were added, and the mixture was heated to 130 ° C. with stirring, and reacted for 1.2 hours while distilling out low-boiling substances generated. 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, and it was found to contain 14.2 g of 3-methyldihydrofurans (reaction yield: 8).
8.8%, 3-methyl-2,5-dihydrofuran: 3-
Methyl-4,5-dihydrofuran = 87:13).

Example 4 The 3-methyldihydrofuran obtained by the method of Example 2 was placed in a 100 ml autoclave (material: Hastelloy C) equipped with a magnetic stirrer, a pressure gauge, a needle valve, a gas inlet and a sampling port. (3-methyl-2,
15 g of 5-dihydrofuran: 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) were put in, and sealed. . After the inside of the autoclave was replaced with nitrogen, the inside of the autoclave was 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 system was replaced with nitrogen, the reaction solution was taken out, and a part thereof was analyzed by gas chromatography (used column: 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, A
(ir 50 kPa), the conversion of 3-methyldihydrofuran was 100%, and the selectivity of 3-methyltetrahydrofuran was 97.2%. The obtained reaction solution was distilled under normal pressure to obtain 13.2 g of 3-methyltetrahydrofuran (purity: 99.8%).

[0026]

According to the present invention, 3-methyltetrahydrofuran and 3
-Methyldihydrofuran can be conveniently and industrially produced at a high yield.

Claims (3)

[Claims] 1. A dehydration reaction of 3-hydroxy-3-methyltetrahydrofuran in the presence of an acidic substance to obtain 3-methyldihydrofuran, and the obtained 3-methyldihydrofuran is reacted with hydrogen in the presence of a hydrogenation catalyst. A method for producing 3-methyltetrahydrofuran, which comprises reacting. 2. A process for producing 3-methyltetrahydrofuran, comprising reacting 3-methyldihydrofuran with hydrogen in the presence of a hydrogenation catalyst. 3. A process for producing 3-methyldihydrofuran, comprising dehydrating 3-hydroxy-3-methyltetrahydrofuran in the presence of an acidic substance.