JP2003073376A - Method for producing cyclic acetal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for efficiently producing a cyclic acetal without using a specific oxidative reaction agent. SOLUTION: An α-ketol represented by the formula (1) is reacted with a diol represented by the formula (2) to produce the cyclic acetal represented by the formula (3) [wherein R<1> is a hydrocarbon group; R<2> , R<3> and R<4> are same or different and each represents hydrogen atom or a hydrocarbon group]. In the reaction, the diol is used in an amount of excessive mol based on 1 mol of the α-ketol. The reaction may be carried out in the absence of a solvent by using the diol in an amount of >=2 mol based on 1 mol of α-ketol. At least one kind of solvent selected from a halogenated hydrocarbon, an ester, a ketone and an alcohol may be used as an extraction solvent. SP value of the extraction solvent may be <=15 MPa<1/2> .

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a cyclic acetal from α-ketool and diol.

[0002]

2. Description of the Related Art Conventionally, an azeotropic dehydration method has been used as a method for producing an acetal compound. That is, under acidic conditions, in an organic solvent that is azeotropic with water, the ketone compound as a raw material is used in an excessive amount of alcohol (eg, glycols).
And coexist with to form an acetal compound under reflux conditions. In the reaction, water produced by acetalization of the ketone compound is removed by an azeotropic dehydration method using a Lean-Stark apparatus or the like, and the acetalization is promoted by maintaining an equilibrium relationship in the acetalization of the ketone compound. .

In the above reaction, as alcohol 1,
When 2-diol or 1.3-diol is used, a cyclic acetal is produced. However, when a short-chain and highly water-soluble raw material such as hydroxyacetone is used as a ketone compound, the raw material may be azeotroped with water and an organic solvent by heating under acidic conditions, or the cleavage of hydroxyacetone ( (Glycolysis) occurs and the yield of the cyclic acetal compound decreases.

Bull Soc Chim Fr Deuxieme Partie No.11
-12 pp.2006-20108 (1976) reported the formation of cyclic acetals using a ketone compound and an epoxide as raw materials. This document also describes that when a halogen acid salt is used as a catalyst and reacted at 100 ° C. for 6 hours or more, the product, a cyclic acetal, is further purified by distillation. However, the yield of the target compound is 70%
It is a degree. It is noted in this document that the cyclic acetal is decomposed by hydrochloric acid into α-ketool and diol.

Tetrahedron Letters Vol.37 No.22 pp.38
81-3884 (1996) reported that a cyclic acetal is produced when 2,2-diethoxypropanol is reacted with ethylene glycol. In this reference, under reflux conditions, p-tosylsulfonic acid is used as a catalyst, and the reaction is carried out at 80 ° C. in the presence of benzene. Also, isolation of the product cyclic acetal by thin layer chromatography has been reported.

Bull. Chem. Soc. JPN Vol. 70, p. 2751 (1997)
Describes a method for producing a cyclic acetal compound using an 1,2 diol as a raw material by using an oxidation reaction agent. In this document, NaBrO ₃ / N is used as an oxidation reaction agent.
aHSO ₃ is used in an aqueous solution as the raw material 1,2-
It is described to ketonize a diol to produce an α-ketool. It is also described that the α-ketool subsequently undergoes a dehydration condensation reaction with unreacted 1,2-diol to form a cyclic acetal. Further, in this document, in the reaction, an oxidation reaction agent is used in a 2.4-fold molar amount relative to 1,2-diol, and 1,2-diol is reacted at a concentration of about 3% by weight with respect to the entire reaction system. An example of this is described. However, the reaction has a long reaction time,
The operation is complicated. A method of extracting unreacted 1,2-diol from the reaction mixture using ether as an extractant is also described, but ether has high flammability and volatility and is inferior in handleability.

Japanese Unexamined Patent Publication (Kokai) No. 9-77705 discloses a specific oxidation reaction agent. In this example, 1,2, 1 and 2 were obtained in the presence of the oxidation reaction agents (NaBrO ₃ and NaHSO ₃ ).
It is described that when propanediol is used as a raw material and oxidized in acetonitrile, hydroxyacetone is produced, and further, a ketal compound in which 1,2-propanediol is added to the produced hydroxyacetone is produced. In the above reaction, the oxidation reaction agent is used in a 2.4-fold molar amount with respect to 1,2-propanediol, and 1,2-propanediol is used in a concentration of about 6% by weight based on the whole reaction system. Further, in this document, the ketal compound is extracted with diethyl ether. But,
This method requires a relatively large amount of oxidation reactant and solvent.

[0008]

SUMMARY OF THE INVENTION It is, therefore, an object of the present invention to provide a method capable of efficiently producing a cyclic acetal under mild conditions without using a specific oxidizing agent.

Another object of the present invention is to provide a method for producing a cyclic acetal in a high yield by a simple method.

[0010]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to achieve the above-mentioned objects, and as a result, when α-ketool and a diol are used as raw materials for reaction, a specific oxidation reaction agent is used. The present invention has been completed by finding that cyclic acetals can be produced in a high yield without the above.

That is, in the method of the present invention, as a raw material, the following formula (1)

[0012]

[Chemical 4]

Α-ketool represented by the formula (wherein R ¹ represents a hydrocarbon group and R ² represents a hydrogen atom or a hydrocarbon group) and the following formula (2)

[0014]

[Chemical 5]

(Wherein R ³ and R ⁴ are the same or different and each represents a hydrogen atom or a hydrocarbon group), and a reaction is carried out with a diol represented by the following formula (3)

[0016]

[Chemical 6]

A cyclic acetal represented by the formula (wherein R ¹ , R ² , R ³ and R ⁴ are the same as above) is produced. In the above reaction, an excess mole of diol is used with respect to α-ketool. In this method, the diol may be used in an amount of 2 times or more the molar amount of α-ketool, or the reaction may be performed in the absence of a solvent. For example, by reacting hydroxyacetone with propylene glycol (2,4-dimethyl-
[1.3] Dioxolan-2-yl) -methanol may be generated. The reaction may be carried out in the presence of an acid catalyst, and the produced cyclic acetal may be extracted with an extraction solvent. As the extraction solvent, at least one selected from halogenated hydrocarbons, esters, ketones, and alcohols can be used, and the solubility parameter of the extraction solvent by the method of Fedors (Solubility Paramater, hereinafter SP
The value) may be 15 MPa ^1/2 or less.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The feature of the present invention is that the α-ketool represented by the formula (1) and the diol represented by the formula (2) are used as raw materials. In the present invention, unlike a reaction system in which a diol is used as a raw material and α-ketool is produced, a cyclic acetal can be obtained in an extremely high yield in a mild reaction system without using a large amount of an oxidation reaction agent.

Examples of the hydrocarbon group represented by R ^{1 to} R ⁴ in the above formulas (1) and (2) include an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, an aryl group and an aralkyl group.

The alkyl group includes C _1-10 alkyl groups (methyl, ethyl, propyl, butyl, isobutyl, t
- butyl, pentyl, straight-chain or branched C _1-8 alkyl group such as hexyl group, preferably a C _1-6 alkyl group, more preferably a C _1-4 alkyl group, especially C _1-2 alkyl group)
Is included.

The alkenyl group includes C _2-10 alkenyl groups such as vinyl, 1-propenyl, 2-propenyl, isopropenyl, butenyl and pentenyl groups, and the alkynyl group includes, for example, ethynyl, Included are C _2-10 alkynyl groups such as propynyl groups.

The cycloalkyl group includes, for example, C _3-20 cycloalkyl group (preferably C _4-10 cycloalkyl group) such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl groups.
Is included. The aryl group includes, for example, a C _6-12 aryl group (phenyl, naphthyl group, etc.) and the like. The aralkyl group such as benzyl, and the like C _6-12 aryl -C _1-4 alkyl group such as a phenethyl group.

These hydrocarbon groups include various substituents [alkyl groups (for example, C _1-6 alkyl groups), alkoxy groups (for example, C _1-6 alkoxy groups), carbonyl groups, acyl groups (for example, C _1-6 alkyl groups). _1-7 alkylcarbonyl group), a carboxyl group, an alkoxycarbonyl group (for example, a C _1-6 alkoxy-carbonyl group), and the like].

R ¹ , R ² , R ³ and R ⁴ may be the same or different, and R ¹ and R ² , R ³ and R ⁴ are bonded to each other to form a non-aromatic ring. May be formed. The non-aromatic ring includes a ring corresponding to a cycloalkyl group, for example, C
Includes _4-10 cycloalkane rings and the like.

Preferred R ¹ is a C _1-8 alkyl group, especially C
_1-6 alkyl group (for example, C _1-4 such as methyl or ethyl group)
Alkyl group). Further, preferred R ^{2 to} R ⁴ are a hydrogen atom, a C _1-8 alkyl group, particularly a C _1-6 alkyl group (for example, a C _1-4 alkyl group such as methyl or ethyl group).

Representative compounds represented by the above formula (1)
Then, for example, R¹Is C_1-4Alkyl group and R²Is hydrogen
The atom α-ketool (eg, hydroxyaceto
C3 to C6 such as hydroxyethyl methyl ketone
Α-ketool), especially R ¹Is a methyl group and R²Is hydrogen
The atom is hydroxyacetone.

The α-ketool may be a commercially available product or may be prepared by oxidizing a polyhydric alcohol with a specific oxidizing agent (for example, halogen acid). For example, excess silver carbonate /
The Celite reagent may be used (Fetizon method) to obtain α-ketool from vicinal diols selectively, and the NaBrO ₃ / NaHSO ₃ oxidation system may be used to obtain α-ketool from diols.

Examples of the diol represented by the above formula (2) include diols in which R ³ is a C _1-4 alkyl group and R ⁴ is a C _1-4 alkyl group or a hydrogen atom (for example, propanediol, butane). Examples thereof include diols and other diols having 2 to 8 carbon atoms, particularly 1,2-diols, and above all, propylene glycol in which R ³ is a methyl group and R ⁴ is a hydrogen atom.

Particularly, the following combinations of R ^{1 to} R ⁴ are preferable. R ¹ : C _1-4 alkyl group (especially C _1-2 alkyl group) R ² : hydrogen atom R ³ : hydrogen atom, C _1-4 alkyl group (especially C _1-2 alkyl group) R ⁴ : hydrogen atom, C _1-4 alkyl group (especially C _1-2 alkyl group) The amount of the diol represented by the formula (2) used is an excess molar amount with respect to the α-ketool represented by the formula (1).
It is preferably 1.2 times or more (for example, 1.2 to 10 times), more preferably 1.5 times or more (for example, 2 to 10 times).
8 times mol), especially 1.8 times mol or more (for example, 2 to 5 times mol), and usually 2 to 3 times mol. In particular, a cyclic acetal can be efficiently obtained by reacting with a diol in a molar amount of 2 times or more.

The cyclic acetal represented by the above formula (3) is produced by the reaction (dehydration reaction) of α-ketool and diol. As a typical example of the cyclic acetal, an acetal compound having a 1.3-dioxolane skeleton and having the same or different C _1-4 alkyl groups [in particular, (2,4-dimethyl- [1.3] Dioxolane-2
-Yl) -methanol] and the like (2,4-diC _1-4 alkyl- [1.3] dioxolan-2-yl) -1-C
_1-4 alcohol, or (2,4,5-tri C _1-4 alkyl- [1.3] dioxolan-2-yl) -1-C _1-4
Examples include alcohol.

The above-mentioned reaction may be carried out in the presence or absence of a catalyst, but it is usually carried out in the presence of a catalyst. The catalyst used in the above reaction is not particularly limited, but an acid catalyst is preferable. When the reaction is carried out in the presence of an acid catalyst, the cyclic acetal can be efficiently obtained even under mild conditions. As the acid catalyst, either a protic acid or a Lewis acid can be used. You may use these acid catalysts individually or in combination of 2 or more types.

As the protic acid, inorganic acids (for example, sulfuric acid, hydrochloric acid, phosphoric acid, halogen acids, etc.), organic acids (for example, p-toluenesulfonic acid, benzenesulfonic acid, methanesulfonic acid, ethanesulfonic acid, etc.) acid,
Chloroacetic acid, trichloroacetic acid, halogenated carboxylic acids such as trifluoroacetic acid, picric acid, etc.), Hammett (Ha
mmett) acidity function H ₀ is less than -11.93 superacids (eg, H ₂ SO ₄ —SO ₃ , HF—NbF ₅ , HF).
-TaF ₅ , SbF ₅ , HF-SbF ₅ , SbF ₅ -FSO
₃ H, FSO ₃ H—TaF ₅ , SbF ₅ —CF ₃ SO ₃ H, etc.) and the like. Examples of the Lewis acid include B
F ₃ , BF ₃ OEt ₂ , AlCl ₃ , FeCl ₃ , ZnC
l ₂ , TiCl ₄ , SnCl _{2 and the} like can be exemplified.

The acid catalyst may be a solid acid catalyst. The solid acid catalyst may be, for example, a catalyst in which the acid catalyst is supported on a carrier or a porous carrier, and is a strongly acidic ion exchange resin (such as a non-porous or porous ion exchange resin containing a sulfonic acid group). , A super strong acidic ion exchange resin (such as a non-porous or porous ion exchange resin having a super strong acid group such as —CF ₂ CF ₂ SO ₃ H). The surface area of the porous carrier supporting the acid catalyst is, for example,
It is about 10 to 5000 m ² / g, and the pore volume and average pore diameter are not particularly limited. The amount of the acid catalyst supported is, for example, about 0.1 to 50% by weight, preferably about 1 to 25% by weight. The solid catalyst may be used as a dispersion (slurry) in the reaction system, or may be used by filling a column in which the reaction components can flow.

The amount of the catalyst used is selected according to the reaction conditions and may be any effective amount, and is 0.001 to 10 parts by weight, preferably 0.1% by weight based on 100 parts by weight of the α-ketool of the above formula (1). 01 to 8 parts by weight, more preferably 0.1 to
It is often about 5 parts by weight.

If the pH in the system is too high, the reaction rate may decrease and the acetal yield may decrease. Therefore, the pH of the reaction system is 5 or less (for example, 0.1
~ 5), preferably 0.5-4, more preferably 0.
It is 8 to 3, especially about 1 to 3.

The reaction temperature is 0 to 150 ° C. (for example, 0 to
Although it can be selected from the range of about 100 ° C., the present invention can efficiently produce a cyclic acetal within a short time even under relatively mild conditions. Therefore, the reaction temperature may be preferably 10 to 80 ° C, more preferably 10 to 50 ° C (for example, 15 to 50 ° C), and particularly room temperature (15 to 30 ° C). Further, the reaction is carried out under normal pressure or under pressure (for example,
It can be performed at 1 × 10 ⁵ to 1 × 10 ⁶ Pa).

The above reaction may be carried out in the presence or absence of a solvent. In addition, when a large amount of solvent is used, the reaction rate is reduced, and solvent removal and recycling steps are required. Therefore, it is preferable to carry out the reaction in the presence of a small amount of solvent, particularly in the absence of solvent. The amount of the solvent used is 0 to 65% by weight, preferably 0 to 50% by weight, more preferably 0 to 30% by weight, based on the whole reaction solution. When a solvent is used, this solvent may be used as an azeotropic solvent for the distillation described later, depending on the kind of the solvent.

In the reaction mixture, usually, in addition to the cyclic acetal formed, unreacted α-ketool, diol,
And water produced by acetalization. After completion of the reaction, the cyclic acetal may be separated by a conventional separation / purification means such as extraction, distillation, concentration, recrystallization, chromatography and the like. When the boiling points of the reaction component and the product are close to each other (for example, when propylene glycol is used as a raw material), it is preferable to separate the unreacted component and the product by an extraction operation. For example, with water
Water and an extractable solvent capable of separating are added to the reaction mixture, and an unreacted component can be separated into an aqueous phase and a product can be separated into an organic phase by an extraction operation. That is, because of its high water solubility, the diol can be easily transferred to the aqueous phase, and the cyclic acetal can be selectively extracted into the organic solvent (organic phase). Further, water and inorganic salts can be removed by partitioning the cyclic acetal into the organic phase by an extraction operation, and dissociation of the cyclic acetal compound into α-ketool and diol can be prevented.

The extraction solvent may be any solvent as long as it can be separated from water, but a solvent having an SP value of 15 MPa ^1/2 or less is preferable. The SP value in the solvent is selected according to the types of reaction components and products, for example, 8 to 15
MPa ^1/2, preferably 9~13MPa ^1/2, more preferably 9.5～12MPa ^1/2 about.

As an example of the extraction solvent, a halogen-based solvent [for example, methylene chloride, chloroform (SP = 9.2) is used.
MPa ^1/2 ), carbon tetrachloride (SP = 8.5 MPa ^1/2 ),
1,2-dichloroethane (SP = 9.9 MPa ^1/2 ),
Chlorobenzene (SP = 9.5 MPa ^1/2 ), dichlorobenzene (SP = 10.0 MPa ^1/2 ), etc.], a ketone solvent [eg, methyl ethyl ketone (SP = 9.3 M)]
Pa ^1/2 ), methyl isobutyl ketone (SP = 8.4M
Pa ^1/2 ), diisobutyl ketone (SP = 7.8 MPa)
^1/2 ) etc.], alcohol solvents [eg heptyl alcohol (SP = 8.3 MPa ^1/2 ), octyl alcohol (SP = 8.2 MPa ^1/2 ), capryl alcohol (SP = 8.1 MPa ^1/2) ), Etc.], ester solvents [methyl acetate (SP = 9.6 MPa ^1/2 ), ethyl acetate (SP = 9.1 MPa ^1/2 ), butyl acetate (SP = 8.
5 MPa ^1/2 ), etc.], or a linear or branched saturated or unsaturated hydrocarbon solvent [eg, hexane (SP = 7.
2 MPa ^1/2 ), heptane (SP = 7.4 MPa ^1/2 ),
Alicyclic hydrocarbons such as aliphatic hydrocarbons such as octane (SP = 6.7MPa ^1/2), cyclohexane (SP = 8.2MPa ^1/2), benzene (SP = 9.2 MPa
^1/2 ), toluene (SP = 8.9 MPa ^1/2 ), xylene (SP = 8.8 MPa ^1/2 ), and other aromatic hydrocarbons, etc.] and the like. Preferred extraction solvents are halogenated hydrocarbons, esters, ketones and alcohols, especially halogenated hydrocarbons such as methylene chloride. You may use the said extraction solvent individually or in combination of 2 or more types. In addition, you may use the said extraction solvent as a reaction solvent in the said reaction.

The extraction operation can be carried out in a conventional manner,
For example, the extraction temperature is 0 to 80 ° C, preferably 5 to 60 ° C.
C., more preferably about 10 to 45.degree.

Furthermore, by combining the extraction operation with the distillation operation, the cyclic acetal can be obtained in a high yield. In the extraction operation, the product (cyclic acetal)
It is possible to increase the ratio of the raw materials (α-ketool and diol), enhance the distillation efficiency in the subsequent distillation operation, and efficiently obtain the cyclic acetal compound.

The distillation operation can be carried out by a conventional method. Distillation is usually carried out using a distillation column (tanan column, packed column), and the number of stages of the distillation column is, for example, 1 to 100, preferably 5 to 80, more preferably 10 to 60,
In particular, it may be about 20 to 50 steps. The distillation operation is not particularly limited, but for example, the column top temperature is -20 ° C to 80 ° C.
(Preferably 0 to 75 ° C., more preferably 20 to 70
℃, especially 40 ~ 65 ℃), tower bottom temperature 40 ~ 100
℃, preferably 45 ~ 90 ℃, more preferably 50 ~
It can be carried out at about 80 ° C. and a column top pressure of 1 × 10 ² to 1 × 10 ³ Pa, preferably about 2 × 10 ² to 8 × 10 ² Pa. Further, the distillate can be refluxed at an appropriate reflux ratio (for example, 0.01 to 50, preferably 0.1 to 40, more preferably about 1 to 30).

In the method of the present invention, the cyclic acetal can be easily produced in a high yield, and further, the extraction operation can easily separate the cyclic acetal from the raw material, which is simple. The desired product can be obtained in high yield by the method.

[0045]

INDUSTRIAL APPLICABILITY In the present invention, since α-ketool and diol are used as the starting materials for the reaction, the cyclic acetal can be efficiently produced under mild reaction conditions without using a specific oxidizing agent. Furthermore, the cyclic acetal can be produced in high yield by a simple method by an extraction operation with a specific extraction solvent.

[0046]

The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited by these examples.

Example 1-1 Hydroxyacetone 50 g and propylene glycol 10
0 g was mixed, and the mixture was stirred at room temperature to give 98
500 mg of wt% sulfuric acid was added. Although a slight exotherm was confirmed during the addition, the temperature was lowered to room temperature after 30 minutes, so the reaction was terminated. When the pH of the reaction system was confirmed with a litmus test paper, it was pH = 1. The amount of acetal in the reaction mixture was determined by gas chromatography to be 73 g (yield 73% based on hydroxyacetone).

Example 1-2 50 g of hydroxyacetone and 15 of propylene glycol
0 g was mixed, and the mixture was stirred at room temperature to give 98
500 mg of wt% sulfuric acid was added. A slight exotherm was observed during the addition, but after 30 minutes the temperature had dropped to room temperature and the reaction was terminated. When the pH of the reaction system was confirmed with a litmus test paper, it was pH = 1. The amount of acetal in the reaction mixture was determined by gas chromatography to be 85 g (hydroxyacetone standard yield: 85%).

Examples 1-3 Hydroxyacetone 50 in 600 g of diethyl ether
g and propylene glycol 150 g are mixed and stirred at room temperature, and 500 mg of 98 wt% sulfuric acid is added to the mixed solution.
Was added. After 30 minutes, the pH of the system was confirmed by litmus test paper, and it was pH = 1. The amount of cyclic acetal in the reaction mixture was determined by gas chromatography to be 57 g (hydroxyacetone standard yield 57%), which was low, but after 24 hours, the yield was 70% by weight.

Comparative Example 1 50 g of hydroxyacetone and 50 of propylene glycol
500 g of 98% by weight sulfuric acid was added to the above mixture while stirring at room temperature. A slight exotherm was observed during the addition, but the temperature dropped to room temperature after 30 minutes, so the reaction was terminated. When the pH of the reaction system was confirmed with a litmus test paper, it was pH = 1. The amount of cyclic acetal in the reaction mixture was determined by gas chromatography to be 34 g (hydroxyacetone standard yield 34%), and the yield did not improve even if the reaction solution was left at room temperature for 24 hours.

From the results of Examples 1-1 to 3 and Comparative Example 1, a cyclic acetal was obtained at a high yield when propylene glycol was used as a raw material in an excess molar amount relative to hydroxyacetone.

Example 2 20 g of hydroxyacetone, 50 of propylene glycol
g, 45 g of cyclic acetal (corresponding to a reaction product of hydroxyacetone and propylene glycol), 100 g of water to a neutral (pH = 7) mixed solution containing 5 g of water and a water-soluble inorganic salt, and water is added. Extraction operation with 100 g of methylene chloride was performed three times from the mixed liquid. After the extraction operation,
In the organic phase, 11 g of hydroxyacetone, 4 g of propylene glycol, and 43 g of acetal compound were extracted.
An acetal compound having a purity of 98% by weight or more was isolated from the organic phase by a distillation operation (column top pressure 4 × 10 ² Pa, distillation temperature 62 to 65 ° C.) at a recovery rate of 93% by weight.

Claims (8)

[Claims] 1. A material represented by the following formula (1): (Wherein R ¹ represents a hydrocarbon group and R ² represents a hydrogen atom or a hydrocarbon group) and an α-ketool represented by the following formula (2): (In the formula, R ³ and R ⁴ are the same or different and each represents a hydrogen atom or a hydrocarbon group) and are reacted with a diol represented by the following formula (3) (Wherein R ¹ , R ² , R ³ and R ⁴ are the same as described above), the method comprising the step of producing α-
A method in which the above-mentioned diol is used in an excess mole with respect to ketool. 2. The production method according to claim 1, wherein the diol is used in an amount of at least 2 times the molar amount of α-ketool. 3. The production method according to claim 1, wherein the reaction is carried out in the absence of a solvent. 4. The production according to claim 1, wherein hydroxyacetone is reacted with propylene glycol to produce (2,4-dimethyl- [1.3] dioxolan-2-yl) -methanol. Method. 5. The method according to claim 1, wherein the reaction is carried out in the presence of an acid catalyst.
4. The method according to any one of 4 above. 6. The production method according to claim 1, wherein the produced cyclic acetal is extracted with an extraction solvent. 7. A halogenated hydrocarbon as an extraction solvent,
The manufacturing method according to claim 6, wherein at least one selected from an ester, a ketone, and an alcohol is used. 8. The production method according to claim 6, wherein a solvent having a solubility parameter of 15 MPa ^1/2 or less is used as the extraction solvent.