JPH0952888A - Production of 2-hydroxy-4-methyltetrahydrofuran - Google Patents

Abstract

PROBLEM TO BE SOLVED: To industrially advantageously obtain the subject compound as an intermediate for a medicine and an agrochemical by reacting 2-methyl-2- propene-1-ol with H2 and CO in the presence of an Rh compound and a specific tris(substituted aryl)phosphite. SOLUTION: The objective compound is industrially advantageously obtained by reacting 2-methyl-2-propene-1-ol with hydrogen and carbon monoxide in the presence of a rhodium compound (e.g.; dicarbonylacetylacetonate rhodium) and a tris(substituted aryl)phosphite expressed by the formula (R<1> -R<3> are each a >=7C substituted aryl) [e.g.; tris(2,4-di-t-butylphenyl)phosphite] having 2,080-2,090cm<-1> electronic-parameter (ν-values) and 135-190 deg.C steric-parameter (θ-values) in an amount of 110-1,000mol times of 1 gram atom of rhodium.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to 2-methyl-2-
It relates to a method for producing 2-hydroxy-4-methyltetrahydrofuran by reacting propen-1-ol (methallyl alcohol) with hydrogen and carbon monoxide in the presence of a rhodium compound. The 2-hydroxy-4-methyltetrahydrofuran obtained by the present invention is useful as a synthetic intermediate for various fine chemicals such as pharmaceuticals and agricultural chemicals. For example, by reduction, a raw material for a polymer compound such as polyester or an organic compound. Can be converted to 2-methyl-1,4-butanediol, which is useful as a synthetic intermediate.

[0002]

2. Description of the Related Art A method for producing an aldehyde by reacting an olefinically unsaturated organic compound with hydrogen and carbon monoxide is called a hydroformylation reaction or an oxo reaction and is an industrially useful synthetic method. In the hydroformylation reaction, a cobalt compound or a rhodium compound is usually used as a catalyst. Among them, rhodium compounds are far superior to cobalt catalysts in catalytic activity for hydroformylation reaction and aldehyde selectivity. As such a rhodium compound, a rhodium carbonyl compound which is a complex of rhodium and carbon monoxide is generally used. However, since the rhodium carbonyl compound itself is a highly reactive and unstable compound, it is usually phosphorus or arsenic. , A compound in the form of being stabilized by modification with a ligand containing antimony, etc. At this time, an organic phosphorus compound such as triphenylphosphine is preferably used as a ligand.

Hydroformylation of allylic alcohols to produce tetrahydrofurans is known, and many examples have been reported. For example, Japanese Patent Publication Sho 53
-19563 discloses a method for synthesizing 2-hydroxytetrahydrofuran by hydroformylating allyl alcohol. According to the method described in the publication, a rhodium compound is used as a catalyst, triphenylphosphine is used as a ligand for modifying the rhodium compound, and 4k is used.
The reaction is carried out at a low pressure of g / cm ² or less, and a high hydroformylation selectivity is achieved. In addition, the literature [J. Pra
kt. Chem., 314 , 840-850 (1972)], RhCl (CO) (PP) which is a rhodium compound in which an allyl alcohol having a substituent is modified with triphenylphosphine.
A method for producing 1,4-butanediols by hydroformylation using h ₃ ) ₂ and subsequent reduction is described. At this time, 2-hydroxytetrahydrofurans are used as intermediate hydroformylation products. Are generated.

[0004]

In order to industrially produce 2-hydroxy-4-methyltetrahydrofuran, which is useful as a synthetic intermediate for various fine chemicals, the present inventors have used 2-methyl-2-methyltetrahydrofuran as a starting material. Propene-1
-Attempting to carry out the synthesis method described in the above-mentioned literature using all-ol, it was recognized that the following problems exist.
That is, the hydroformylation of 2-methyl-2-propen-1-ol is carried out using a rhodium compound having triphenylphosphine as a ligand, which has been most favored in the industry as a catalyst, at 4 kg / cm. ^When carried out at a low pressure of ² or less, the reaction rate is extremely low. Therefore, in order to industrially carry out the hydroformylation of 2-methyl-2-propen-1-ol, the concentration of the rhodium catalyst must be increased. However, since the rhodium compound is extremely expensive, if it is not used as a catalyst for a long period of time, the economical efficiency will be impaired. On the other hand, the reaction pressure is, for example, 100 kg / cm ²
Although the reaction rate of the hydroformylation increases when it is increased to 1, it is still impossible to reduce the amount of the rhodium compound used so as to be economically satisfactory.

Therefore, 2-methyl-2-propene-1-
2-hydroxy-4 by hydroformylation of all
In order to industrially produce methyltetrahydrofuran, it is important to construct a catalyst system using a ligand such that the reaction rate is higher than that when triphenylphosphine is used as the ligand. It becomes an issue.

[0006]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a specific phosphorus compound is reacted when 2-methyl-2-propen-1-ol is hydroformylated. It was found that, when coexisting in the system, the reaction rate can be increased even if the concentration of the rhodium compound as the catalyst is low, and the reaction system can be industrially advantageously carried out, and the present invention has been completed. .

That is, the present invention provides an electronic parameter (Electron parameter) of 110 to 1000 mole times per 1 gram atom of rhodium compound and rhodium.
nic Parameter: ν-Values) is 2
080 to 2090 cm ⁻¹ and a steric parameter (Steric Parameter: θ-Va
The following general formula (1), in which

[0008]

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In the presence of tris (substituted aryl) phosphite represented by the formula (wherein R ¹ , R ² and R ³ each represent a substituted aryl group having 7 or more carbon atoms), 2-methyl-2-propene is present. A method for producing 2-hydroxy-4-methyltetrahydrofuran, which comprises reacting -1-ol with hydrogen and carbon monoxide.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The above-mentioned two parameters in the present invention are the same as those in the literature [CATolman, Chem. Rev., 177 , 313 (19).
77)], and the electronic parameter is defined as the frequency of the A1 infrared absorption spectrum of CO of Ni (CO) ₃ L (L is a phosphorus ligand) measured in dichloromethane. And the steric parameter is 2.2 from the center of the phosphorus atom.
It is defined by the apex angle of a cone drawn around the van der Waals radius of the outermost atom bound to phosphorus at the 8 angstrom position.

Tris (substituted aryl) used in the present invention
Phosphite has an electronic parameter of 20.
It is required to be 80 to 2090 cm ⁻¹ and the steric parameter to be 135 to 190 °. When a tris (substituted aryl) phosphite having either an electronic parameter or a steric parameter outside this range is used, a large reaction rate and a 2-methyl-2-propen-1-ol hydroformylation reaction are obtained. A high selectivity to hydroxy-4-methyltetrahydrofuran cannot be achieved at the same time.

R ¹ , R ² and R ³ in the above general formula (1) each represent a substituted aryl group having 7 or more carbon atoms. There is no particular upper limit on the number of carbon atoms of R ¹ , R ² and R ³ . The substituted aryl group may have any substituent as long as it does not hinder the hydroformylation reaction. Examples of such a substituted aryl group include a tolyl group, a xylyl group, a t-butylphenyl group, and the like.

Here, a specific example of the tris (substituted aryl) phosphite used in the present invention is as follows.
-Methylphenyl) phosphite, tris (2,6-dimethylphenyl) phosphite, tris (2-isopropylphenyl) phosphite, tris (2-phenylphenyl) phosphite, tris (2-t-butylphenyl) phosphite , Tris (2-t-butyl-5-methylphenyl) phosphite, tris (2,4-di-t-)
Butylphenyl) phosphite, di (2-methylphenyl) (2-t-butylphenyl) phosphite, di (2
-T-butylphenyl) (2-methylphenyl) phosphite and the like can be mentioned, and among these, tris (2
-T-butylphenyl) phosphite, tris (2-t
-Butyl-5-methylphenyl) phosphite and tris (2,4-di-t-butylphenyl) phosphite are preferable for industrially carrying out the present invention. As the tris (substituted aryl) phosphite, one kind of compound may be used, or two or more kinds of compounds may be used in combination.

As the rhodium compound used in the present invention, any rhodium compound having a hydroformylation catalytic ability or changing to have a hydroformylation catalytic ability under hydroformylation reaction conditions can be used. Specific examples of such rhodium compounds include, for example, Rh ₄ (CO) ₁₂ , Rh ₆ (CO) ₁₆ , Rh (aca
c) (CO) ₂ , rhodium oxide, rhodium chloride, rhodium acetylacetonate, rhodium acetate and the like.

Since the above rhodium compound exhibits an extremely highly active catalytic action, the concentration of the rhodium compound in the hydroformylation reaction according to the present invention is 0.005 to 0.03 mg atom / liter in terms of rhodium atom. It is desirable to set it in the low concentration range.

In the present invention, tris (substituted aryl) phosphite is added to 11 g / atom of rhodium.
It is used in a concentration range of 0 to 1000 molar times. The amount of tris (substituted aryl) phosphite used is
When the concentration is less than 110 mol times relative to 1 gram atom of rhodium, the selectivity in the hydroformylation reaction is lowered, and at the same time, the thermal deterioration of the catalyst is promoted when the product is separated from the reaction mixture by evaporation, and the catalytic activity is lowered. Tend to cause. On the other hand, if the amount of tris (substituted aryl) phosphite to be used exceeds 1000 mol times per gram atom of rhodium, the rate of the hydroformylation reaction tends to decrease, which is not preferable.

The hydroformylation reaction according to the present invention is usually at a temperature in the range of 60 to 150 ° C., preferably 80 to 1
It is carried out at a temperature in the range of 30 ° C. Reaction temperature is 60 ℃
If it is less than the above range, the reaction rate tends to be low, while if the reaction temperature exceeds 150 ° C., it tends to be difficult to maintain the stability of the rhodium compound present as a catalyst.

In the mixed gas of hydrogen and carbon monoxide used in the reaction, the molar ratio of hydrogen / carbon monoxide is usually selected from the range of 1/5 to 5/1 as the gas composition. It should be noted that a small amount of a gas inert to the hydroformylation reaction, such as methane, ethane, propane, nitrogen, helium, or argon, may be present in the reaction system.

Although the reaction pressure depends on the reaction temperature, it is generally 6
It is selected from the range of 0 to 150 atm. Reaction pressure is 60
If the pressure is less than atmospheric pressure, the selectivity in the hydroformylation reaction tends to be low. On the other hand, from the viewpoint of the apparatus used for the reaction and the operability, it is industrially advantageous to carry out the reaction while maintaining the reaction pressure at 150 atm or less. The reaction can be carried out continuously or batchwise in a stirred reaction tank or a bubble column reaction tank.

The hydroformylation reaction in the present invention comprises
Although it can be carried out in the absence of a solvent, it may be carried out in the presence of an inert solvent in the reaction system. Examples of such a solvent include alcohols such as ethanol, butanol, ethylene glycol; saturated aliphatic hydrocarbons such as hexane, heptane, octane; benzene, toluene,
Examples thereof include aromatic hydrocarbons such as xylene, cumene, pseudocumene, and ethylbenzene; esters such as ethyl acetate and dioctyl phthalate; ethers such as tetrahydrofuran.

In addition, in the hydroformylation reaction of the present invention, by adding a tertiary amine to the reaction system,
It is possible to suppress the acetalization reaction of 2-hydroxy-4-methyltetrahydrofuran, prevent the formation of by-products, and increase the yield of 2-hydroxy-4-methyltetrahydrofuran. The concentration of the tertiary amine is preferably 100 mmol or less with respect to 1 liter of the reaction solution, and more preferably 20 mmol or less with respect to 1 liter of the reaction solution. If the concentration of the tertiary amine exceeds 100 mmol with respect to 1 liter of the reaction solution, the reaction rate tends to decrease.

Specific examples of such tertiary amines include aliphatic alkyl tertiary amines such as triethylamine, tributylamine and trioctylamine; N,
Alkyl-substituted tertiary diamines such as N, N ', N'-tetramethyl-1,2-diaminoethane, N, N, N', N'-tetramethyl-1,3-diaminopropane; N, N
-Tertiary alkanolamines such as dimethylethanolamine and triethanolamine; alicyclic tertiary amines such as N-methylpiperidine, N-methylpyrrolidine and N-methylmorpholine; cyclic unsaturated such as pyridine and lutidine Examples thereof include tertiary amines.

2 produced by the hydroformylation reaction
-Hydroxy-4-methyltetrahydrofuran can be separated from the catalyst by evaporating the reaction mixture under reduced pressure at a temperature of about 130 ° C or lower, for example. Then, 2-hydroxy-4-methyltetrahydrofuran can be isolated by purifying the fraction containing 2-hydroxy-4-methyltetrahydrofuran obtained by evaporation using a known means such as distillation. In addition, all or part of the rhodium compound contained in the evaporation residue can be recycled to the hydroformylation reaction and reused. Since rhodium compounds are extremely expensive,
The cyclic reuse of rhodium compounds is industrially advantageous.

The 2-hydroxy-4-methyltetrahydrofuran thus obtained can be converted into 2-methyl-1,4-butanediol by contacting it with hydrogen in the presence of a hydrogenation catalyst. As a raw material for hydrogenation, a fraction containing 2-hydroxy-4-methyltetrahydrofuran obtained by evaporation from a reaction mixture obtained by a hydroformylation reaction may be used, or a 2-fraction isolated from the fraction may be used. Hydroxy-4-methyltetrahydrofuran may be used.

As the hydrogenation catalyst, known catalysts used for hydrogenation of aldehydes can be used, and examples thereof include Raney nickel, Raney cobalt, palladium black,
A copper chromite catalyst etc. are mentioned. Further, nickel diatomaceous earth in which these metals are supported on activated carbon, diatomaceous earth, alumina, etc., palladium alumina, ruthenium carbon, etc. can also be used. These catalysts may be partially modified with molybdenum, tungsten, iron, rhenium, manganese, tungsten or the like.

When the reaction is carried out in a liquid phase suspension system, the amount of hydrogenation catalyst used is 0.0 in terms of metal based on the reaction mixture.
It is preferably from 1 to 10% by weight.

Hydrogenation of 2-hydroxy-4-methyltetrahydrofuran is preferably carried out at a temperature in the range of 20 to 150 ° C, more preferably at a temperature in the range of 50 to 150 ° C. The hydrogen pressure is preferably in the range of 1 to 100 atm, more preferably in the range of 5 to 100 atm.

The hydrogenation of 2-hydroxy-4-methyltetrahydrofuran can be carried out in the absence of a solvent, but it may also be carried out in the presence of a solvent inert to the reaction. Examples of the solvent include alcohols such as methanol, ethanol, propanol, butanol, and octanol; saturated aliphatic hydrocarbons such as hexane, heptane, and octane; ethers such as dibutyl ether, tetrahydrofuran, and dioxane.

The hydrogenation of 2-hydroxy-4-methyltetrahydrofuran can be carried out in a stirred type or bubble column type reactor with the catalyst suspended in the liquid phase, or fixed with a supported catalyst. It can also be carried out in a bed reactor. Further, it can be carried out by either a continuous system or a batch system.

2-Methyl-1,4-butanediol, which is a hydrogenation product of 2-hydroxy-4-methyltetrahydrofuran, is obtained by separating the catalyst from the reaction mixture by filtration, centrifugation, etc., and then by known methods such as distillation. It can be isolated by any means.

[0031]

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

Example 1 Content 300 m with gas inlet and sampling port
0.31 mg (0.0012 mmol) of dicarbonylacetylacetonato rhodium and tris (2,4-di-t-butylphenyl) phosphite [electronic parameter: ν = 20
85.6 cm ^-1 , steric parameter: θ = 175
°] 646 mg (1 mmol), 2-methyl-2-propen-1-ol 100 ml (25 ° C, 1.19 mol)
And triethanolamine 149 mg (1 mmol)
Was charged without touching the air, and the autoclave was filled with hydrogen / carbon monoxide = 3/1 mixed gas at 90 kg / c.
The pressure was kept at m ² . A mixed gas of hydrogen / carbon monoxide = 3/1 was supplied, stirring was started at 1000 rpm while flowing off gas at 30 l / h, and the temperature in the autoclave was raised to 90 ° C. over 30 minutes. In this state, the reaction was performed for 2.5 hours. When the obtained reaction mixture was analyzed by gas chromatography, the conversion rate of 2-methyl-2-propen-1-ol as a raw material was 90%, and the hydroformylation selectivity was 87%.

After the reaction was completed, the contents were taken out from the autoclave, and the product and the catalyst were separated at 125 ° C. under a reduced pressure of 2.0 mmHg using a molecular distillation apparatus.
The evaporating component of was obtained. By further distilling 110 g of this evaporated component under reduced pressure, 86 g (0.84 mol) of 2-hydroxy-4-methyltetrahydrofuran was obtained.

Comparative Example 1 In Example 1, triphenylphosphine [electronic parameter: ν = 20 was used instead of 646 mg of tris (2,4-di-t-butylphenyl) phosphite.
68.9 cm ^-1 , steric parameter: θ = 145
[°] 2-methyl-2-propene-1- by the same operation as in Example 1 except that 262 mg (1 mmol) was used.
When the hydroformylation reaction of all was carried out, the conversion rate of the raw material was only 29%. The hydroformylation selectivity was 89%.

Example 2 Content 300 m with gas inlet and sampling port
0.181 mg (0.0007 mmol) of dicarbonylacetylacetonato rhodium and tris (2,4-di-t-butylphenyl) in a magnetic stirring autoclave of 1.
226 mg (0.35 mmol) of phosphite, 100 ml of 2-methyl-2-propen-1-ol (25 ° C,
1.19 mol) and triethanolamine 75 mg
(0.5 mmol) was charged without touching the air, and the pressure in the autoclave was maintained at 60 kg / cm ² with a mixed gas of hydrogen / carbon monoxide = 1/1. Supply a mixed gas of hydrogen / carbon monoxide = 1/1 and set off gas to 1
Stirring was started at 1000 rpm while flowing at 0 liter / h, and the temperature in the autoclave was raised to 90 ° C. over 30 minutes. In this state, the reaction was performed for 6 hours. The obtained reaction mixture was analyzed by gas chromatography to find that the raw material conversion rate was 84% and the hydroformylation selectivity was 85%.
Met.

Comparative Example 2 In Example 2, the charged amount of tris (2,4-di-t-butylphenyl) phosphite was 45.2 mg (0.
(7 mmol) except that the hydroformylation reaction of 2-methyl-2-propen-1-ol was carried out in the same manner as in Example 2, and the conversion of the raw material was 89.
%, The hydroformylation selectivity was 57%.

Example 3 Content 300 m with gas inlet and sampling port
0.516 mg (0.002 mmol) of dicarbonylacetylacetonato rhodium, tris (2-t-butyl-5-methylphenyl) phosphite [electronic parameter: ν
= 2085.6 cm ^-1 , steric parameter: θ =
175 °] 520 mg (1 mmol) and 2-methyl-2-propen-1-ol 100 ml (25 ° C., 1.
(19 mol) so that it is not exposed to air, and the inside of the autoclave is filled with a mixed gas of hydrogen / carbon monoxide = 1/1.
The pressure was kept at 20 kg / cm ² . Hydrogen / carbon monoxide =
A 1/1 mixed gas was supplied and stirring was started at 1000 rpm while flowing off gas at 10 liter / h, and the temperature in the autoclave was raised to 90 ° C. over 30 minutes.
In this state, the reaction was performed for 3 hours. When the obtained reaction mixture was analyzed by gas chromatography, the conversion rate of the raw materials was 91% and the hydroformylation selectivity was 90%.

Reference Example An electromagnetic stirring autoclave having a gas introduction port and a sampling port and having a content of 1 liter was charged with 100 g of the evaporation component obtained in Example 1, 250 g of methanol and 5 g of Raney nickel, and the inside of the autoclave was replaced with hydrogen gas. After that, hydrogen gas was kept at a pressure of 50 kg / cm ² . Stirring was started at 1000 rpm, and the temperature inside the autoclave was raised to 80 ° C. While maintaining the pressure inside the autoclave at 50 kg / cm ² , the reaction was carried out at 80 ° C. for 3 hours, further heated to 100 ° C. and reacted at the same temperature for 3 hours. All the charged raw materials were hydrogenated. . 85 g of the obtained reaction mixture was purified by distillation to obtain 70 g (0.67 mol) of 2-methyl-1,4-butanediol.
Obtained.

[0039]

According to the present invention, when carrying out the hydroformylation reaction of 2-methyl-2-propen-1-ol, a reaction which is industrially satisfactory even when the rhodium catalyst used is at a low concentration. The rate is achieved and 2-hydroxy-4-methyltetrahydrofuran can be obtained in good yield.

Claims (4)

[Claims] 1. A rhodium compound and an electronic parameter (Electronic Parameter) of 110 to 1000 mol times per 1 gram atom of rhodium.
ter: ν-Values) is 2080 to 2090 cm
^-1 and the steric parameter (Steric
Parameter: θ-Values) is 135-
The following general formula (1) is 190 ° (Wherein each of R ¹ , R ² and R ³ represents a substituted aryl group having 7 or more carbon atoms) in the presence of tris (substituted aryl) phosphite, 2-methyl-2-propene-1- A process for producing 2-hydroxy-4-methyltetrahydrofuran, which comprises reacting all with hydrogen and carbon monoxide. 2. The rhodium compound is used in a concentration range of 0.005 to 0.03 milligram atom / liter in terms of rhodium atom, and the reaction pressure is 60 to 150 atm. 2-hydroxy-4
-Method for producing methyltetrahydrofuran. 3. The tris (substituted aryl) phosphite is tris (2-t-butylphenyl) phosphite, tris (2-t-butyl-5-methylphenyl) phosphite, tris (2,4-di-t). 2-butylphenyl) phosphite, which is at least one compound selected from the group consisting of
Method for producing hydroxy-4-methyltetrahydrofuran. 4. The 2-hydroxy-4-methyltetrahydrofuran according to claim 1, wherein the tertiary amine is added in a concentration range of 100 mmol or less per 1 liter of the reaction solution. Production method.