Method for producing acetal and system for producing dialkyl carbonate

Abstract

To provide a novel method for producing an acetal from a carbonyl compound and an alcohol.SOLUTION: A method for producing an acetal is provided, comprising an acetalization reaction step in which a carbonyl compound having either or both of a ketonic carbonyl group and a formyl group is reacted with an alcohol in the presence of a solid acid catalyst and a solid dehydrating agent.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a method for producing acetals and a system for producing carbonate diesters. [Background technology]

[0002] Acetal is widely used as a raw material for various industrial products, and the development of its manufacturing methods is being actively pursued.

[0003] Acetals are generally produced by reacting a ketone or an aldehyde with an alcohol. For example, Non-Patent Document 1 discloses a method for producing an acetal using a strongly acidic cation exchange resin as a catalyst, and Non-Patent Document 2 discloses a method for producing an acetal using an ionic liquid as a catalyst. Furthermore, Non-Patent Document 3 discloses a method for producing acetal by reacting acetone with supercritical methanol in the absence of a catalyst. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] NB LORETTE et al., The Journal of Organic Chemistry, Vol.24, No.11, 1959, p.1731-1733 [Non-Patent Document 2] Hui Jiang et al., Green Chemistry, Vol.8, 2006, p.1076-1079 [Non-Patent Document 3] Yoshiteru Horikawa et al., Chemistry Letters, Vol.32, No.3, 2003, p.232-233 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the method described in Non-Patent Document 1 has a problem that the conversion rate is low under 24°C conditions, and the reaction must be carried out at a low temperature of -28°C, and when acyclic ketones such as acetone and butanone are used as substrates, acetal can only be obtained in low yield. In addition, the method described in Non-Patent Document 2 requires the use of an expensive ionic liquid as a catalyst. On the other hand, Non-Patent Document 3 does not require the use of a catalyst, but it also requires the reaction to be carried out under conditions in which the alcohol is in a supercritical state, and the reaction does not proceed unless the temperature is as high as 350°C, and acetal can only be obtained in a low yield of less than 30%. Therefore, there is a demand for the development of a new method for producing acetal that is different from these.

[0006] An object of the present disclosure is to provide a novel method for producing an acetal from a carbonyl compound and an alcohol. [Means for solving the problem]

[0007] The present inventors have conducted intensive research to solve the above problems, and as a result have found that an acetal can be efficiently produced by reacting a carbonyl compound with an alcohol in the presence of a solid acid catalyst and a solid dehydrating agent.

[0008] [1] A method for producing an acetal, comprising an acetalization reaction step of reacting a carbonyl compound having either or both of a ketonic carbonyl group and a formyl group with an alcohol in the presence of a solid acid catalyst and a solid dehydrating agent. [2] The carbonyl compound is a compound represented by general formula (1), The method for producing an acetal according to [1], wherein the alcohol is a compound represented by general formula (2). [ka] R 3 OH (2) (In the general formula, R 1R is an aliphatic hydrocarbon group which may have a substituent; 2 represents an aliphatic hydrocarbon group which may have a substituent or a hydrogen atom; R 3 R is an aliphatic hydrocarbon group which may have a substituent; 1 and R 2 When both are aliphatic hydrocarbon groups, R 1 and R 2 may be bonded to each other via a single bond or a linking group to form a ring. [3] The method for producing an acetal according to [1] or [2], wherein the solid acid catalyst is a cation exchange resin. [4] The method for producing an acetal according to any one of [1] to [3], wherein the solid dehydrating agent is a molecular sieve. [5] The method for producing an acetal according to any one of [1] to [4], wherein the acetalization reaction step is carried out using a rotary reactor having a cartridge filled with one or more selected from the group consisting of the solid acid catalyst and the solid dehydrating agent. [6] an acetal production unit that produces an acetal by reacting a carbonyl compound having either or both of a ketonic carbonyl group and a formyl group with an alcohol in the presence of a solid acid catalyst and a solid dehydrating agent; a hydrolysis section for hydrolyzing the acetal produced in the acetal production section to produce a carbonyl compound having either or both of a ketonic carbonyl group and a formyl group, and an alcohol; a carbonic acid diester production section for producing a carbonic acid diester from a raw material containing carbon dioxide and the alcohol produced in the hydrolysis section; A system for producing a carbonate diester comprising: Effect of the Invention

[0009] According to the present disclosure, a novel method for producing an acetal from a carbonyl compound and an alcohol can be provided. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram of a rotating reactor used in an embodiment of the present disclosure. [Diagram 2] FIG. 1 is a conceptual diagram illustrating a carbonic acid diester production system according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The present disclosure will be described in detail below. However, the description of the constituent elements described below is an example (representative example) of an embodiment of the present disclosure, and the present disclosure is not limited to these contents, and can be implemented in various modifications within the scope of its gist.

[0012] In this specification, the term "X to Y" indicating a range means "X or more and Y or less". In addition, the range of values ​​represented by "X to Y" or "X or more and Y or less" is described in a stepwise manner (for example, in order of preference). When specified, the upper and lower limits of each numerical range can be combined in any way.

[0013] [1. Method for producing acetal] A first embodiment of the present disclosure is a method for producing an acetal, comprising an acetalization reaction step of reacting a carbonyl compound having either a ketonic carbonyl group or a formyl group, or both, with an alcohol in the presence of a solid acid catalyst and a solid dehydrating agent.

[0014] According to this embodiment, an acetal can be produced from a carbonyl compound and an alcohol. In addition, in this embodiment, since the catalyst is a solid acid catalyst and the dehydrating agent is also a solid dehydrating agent, the catalyst and the dehydrating agent can be easily separated and recovered by centrifugation, filtration, or the like after the acetalization reaction step. Furthermore, according to a preferred aspect of this embodiment, it is not necessary to react the raw material in a supercritical state, and the reaction proceeds at about 0°C to room temperature without low or high temperature conditions, and acetals can be produced in good yields. Also, according to a preferred aspect of this embodiment, acetals can be produced in good yields from various carbonyl compounds such as acyclic ketones, cyclic ketones, and aldehydes, and therefore the present invention has high industrial utility value. In this disclosure, "room temperature" refers to a temperature range of 15°C to 35°C.

[0015] [1.1 Carbonyl compounds] In this embodiment, the carbonyl compound serving as the raw material for the acetal is not particularly limited as long as it is a compound having either or both of a ketonic carbonyl group and a formyl group, and can be appropriately selected depending on the target acetal. The number of ketonic carbonyl groups and formyl groups in the carbonyl compound is not particularly limited, but is preferably 1 to 3, more preferably 1 or 2, and even more preferably 1.

[0016] Suitable carbonyl compounds include compounds represented by the general formula (1).

[0017] [ka]

[0018] In general formula (1), R 1 R is an aliphatic hydrocarbon group which may have a substituent; 2 represents an aliphatic hydrocarbon group which may have a substituent or a hydrogen atom; R 1 and R 2 When both are aliphatic hydrocarbon groups, R 1 and R 2 may be bonded to each other via a single bond or a linking group to form a ring. In the present disclosure, the "aliphatic hydrocarbon group" may be linear, branched, or cyclic, and may have a carbon-carbon unsaturated bond.

[0019] R1 is preferably an unsubstituted aliphatic hydrocarbon group. R 1 The number of carbon atoms in the unsubstituted aliphatic hydrocarbon group represented by the following formula is not particularly limited, but is preferably 1 or more and 20 or less, more preferably 2 or more and 16 or less, and further preferably 3 or more and 8 or less.

[0020] R 1 Examples of the unsubstituted aliphatic hydrocarbon group represented by the formula (I) include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an isobutyl group, an n-pentyl group, an isopentyl group, a neopentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, a 2-ethylhexyl group, an n-nonyl group, an n-decyl group, Examples of the alkyl group include an n-undecyl group, an n-dodecyl group, an n-tridecyl group, an n-tetradecyl group, an n-pentadecyl group, an n-hexadecyl group, an n-heptadecyl group, an n-octadecyl group, an n-nonadecyl group, and an n-icosyl group; a cycloalkyl group, such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, and a cyclohexylmethyl group; an alkenyl group, such as a vinyl group, an allyl group, a propenyl group, an isopropenyl group, a butenyl group, a 2-methylallyl group, a pentenyl group, an isopentenyl group, a hexenyl group, a heptenyl group, an octenyl group, a nonenyl group, and a decenyl group; and isomeric groups thereof. Of these, an alkyl group is preferable.

[0021] R 1In the case where the aliphatic hydrocarbon group represented by the formula (I) has a substituent, the substituent is not particularly limited as long as it does not inhibit the acetalization reaction, and examples thereof include deuterium atoms; alkyl groups having 1 to 4 carbon atoms, such as methyl groups, ethyl groups, n-propyl groups, isopropyl groups, n-butyl groups, sec-butyl groups, isobutyl groups, and tert-butyl groups; cycloalkyl groups having 3 to 6 carbon atoms, such as cyclopropyl groups, cyclobutyl groups, cyclopentyl groups, and cyclohexyl groups; methoxy groups, ethoxy groups, n-propoxy groups, isopropoxy groups, n-butoxy groups, sec-butoxy groups, isobutoxy groups, cycloalkyloxy groups having 3 to 6 carbon atoms, such as cyclopropyloxy, cyclobutoxy, cyclopentyloxy, and cyclohexyl groups; aromatic hydrocarbon groups having 6 to 12 carbon atoms, such as phenyl, 1-naphthyl, and 2-naphthyl groups; heterocyclic groups, such as furanyl, thienyl, morpholino, and pyridyl groups; aralkyl groups, such as benzyl and 2-phenylethyl groups; halogeno groups, such as fluoro, chloro, bromo, and iodo groups; hydroxyl groups; and nitro groups.

[0022] R 2 The optionally substituted aliphatic hydrocarbon group represented by R 1 The meaning of the optionally substituted aliphatic hydrocarbon group represented by the following formula (1) is the same as that of the optionally substituted aliphatic hydrocarbon group represented by the following formula (1), and preferred embodiments thereof are also the same.

[0023] R 1 and R 2 When they are bonded to each other via a single bond or a linking group to form a ring, the linking group is not particularly limited as long as it does not inhibit the acetalization reaction, and examples of the linking group include -CH 2 Examples include -, -O-, and -S-.

[0024] Specific examples of the carbonyl compound represented by the general formula (1) include acetone, methyl ethyl ketone, methyl propyl ketone, diethyl ketone, cyclohexanone, etc. Among these, the carbonyl compound is preferably at least one selected from acetone, methyl ethyl ketone, methyl propyl ketone, diethyl ketone, and cyclohexanone.

[0025] The carbonyl compounds may be used alone or in any combination of two or more in any ratio.

[0026] [1.2 Alcohol] In the present embodiment, the alcohol serving as the raw material for the acetal is not particularly limited and can be appropriately selected depending on the target acetal.

[0027] The alcohol may be an aliphatic alcohol or an aromatic alcohol, but is preferably an aliphatic alcohol. The alcohol may be a polyhydric alcohol or a mono-ol, but is preferably a mono-ol. Therefore, the alcohol is preferably an aliphatic mono-ol, and more specifically, a compound represented by the general formula (2) is preferably used.

[0028] R 3 OH (2) In general formula (2), R 3 represents an aliphatic hydrocarbon group which may have a substituent.

[0029] R 3 The optionally substituted aliphatic hydrocarbon group represented by R 1 The preferred embodiments are also the same as those of the optionally substituted aliphatic hydrocarbon group represented by the following formula (i) and (ii), except for the following formula (i) and (ii). (i)R 3 The number of carbon atoms of the unsubstituted aliphatic hydrocarbon group represented by the following formula is preferably 1 or more and 10 or less, more preferably 1 or more and 4 or less, and further preferably 2 or more and 3 or less. (ii)R 3The optionally substituted aliphatic hydrocarbon group represented by the following formula (I) is preferably an unsubstituted alkyl group, more preferably an unsubstituted primary alkyl group.

[0030] Specific examples of the alcohol represented by the general formula (2) include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutyl alcohol, n-pentanol, n-hexanol, n-heptanol, n-octanol, 2-ethylhexanol, n-nonanol, and n-decanol, etc. Among these, the alcohol is preferably one or more selected from methanol, ethanol, n-propanol, and n-butanol, more preferably one or more selected from methanol, ethanol, and n-propanol, and even more preferably ethanol.

[0031] The alcohol may be used alone or in any combination of two or more in any ratio.

[0032] The amount of alcohol used in the acetalization reaction step is not particularly limited. In this embodiment, as shown in the examples described later, acetal can be produced in high yield regardless of the molar ratio of alcohol to carbonyl compound.

[0033] However, from the viewpoint of reaction rate, production costs, and the like, the amount of alcohol used (charged amount) is preferably k×0.4 mol or more and k×20.0 mol or less, preferably k×1.0 mol or more and k×15.0 mol or less, and more preferably k×2.0 mol or more and k×10.0 mol or less, relative to 1 mol of the carbonyl compound used (charged amount) (k is the total number of ketonic carbonyl groups and formyl groups per molecule of the carbonyl compound).

[0034] [1.3 Acetal] The acetal obtained by the production method according to the present embodiment is an acetal having a structure derived from the above-mentioned raw materials. A suitable acetal is a compound represented by general formula (3). The compound represented by general formula (3) is an acetal obtained by reacting a carbonyl compound represented by general formula (1) with an alcohol represented by general formula (2).

[0035] [ka]

[0036] R in general formula (3) 1 and R 2 respectively represent R in general formula (1). 1 and R 2 The same applies to the preferred embodiments thereof. 3 R in general formula (2) 3 The two R in the general formula (3) have the same meaning and preferred embodiments. 3 may be the same or different, but is preferably the same.

[0037] Specific examples of the acetal represented by the general formula (3) include the following compounds.

[0038] [ka]

[0039] [1.4 Solid acid catalyst] In the acetalization reaction step in this embodiment, a solid acid catalyst is used as a catalyst for promoting the reaction between a carbonyl compound and an alcohol. The solid acid catalyst may be an inorganic solid acid catalyst or an organic solid acid catalyst. When the solid acid catalyst is recovered after the reaction and reused in the production of acetal, the solid acid catalyst is preferably an organic solid acid catalyst, since the solid acid catalyst can exhibit high catalytic activity even if it is repeatedly reused.

[0040] Examples of inorganic solid acid catalysts include zeolites or montmorillonites having protic hydrogen atoms or cations of elements of Groups 3 to 15, mesoporous substances, heteropolyacids, sulfated zirconia, and sulfated nanographene. Of these, the inorganic solid acid catalyst is preferably at least one selected from zeolites and sulfated zirconia.

[0041] Examples of cations of elements in groups 3 to 15 include scandium (III), lanthanum (III), cerium (III), neodymium (III), samarium (III), titanium (IV), zirconium (IV), iron (III), ruthenium (II), nickel (II), palladium (II), copper (II), zinc (II), aluminum (III), gallium (III), indium (III), and tin (IV). Among these, examples of cations of elements in groups 3 to 15 include scandium (III), lanthanum (III), cerium (III), titanium (IV), zirconium (IV), iron (III), zinc (II), aluminum (III), gallium (III), indium (II), and the like. Of these, at least one selected from tin(IV) and tin(IV) is preferred.

[0042] Among montmorillonites, montmorillonite having one or more cations selected from lanthanum (III), cerium (III), titanium (IV), zirconium (IV), iron (III), aluminum (III), gallium (III), indium (III), and tin (IV) as cations of elements of Groups 3 to 15; and montmorillonite having protic hydrogen atoms; are more preferred, and montmorillonite having one or more cations selected from gallium (III), indium (III), and tin (IV) is even more preferred.

[0043] Montmorillonite having cations of elements of groups 3 to 15 can be easily prepared, for example, by treating a commercially available montmorillonite having sodium(I) (e.g., "Kunipia F" manufactured by Kunimine Kogyo Co., Ltd.) with an aqueous solution containing cations of elements of groups 3 to 15. In addition, as the montmorillonite having protonic hydrogen atoms, commercially available products can be used, etc. Examples of commercially available montmorillonite having protonic hydrogen atoms include "Montmorillonite K10" and "Montmorillonite K30" manufactured by Merck & Co., Inc.

[0044] As the zeolite, various types of zeolite having a basic skeleton such as Y type, beta type, ZSM-5 type, mordenite type, and SAPO type can be used, and from the viewpoint of catalytic activity, Y type is preferred.

[0045] In addition, USY-type zeolite (Ultrastable Y), also known as SUSY-type (Super Ultrastable Y), VUSY-type (Very Ultrastable Y), and SDUSY-type (Super Dealuminated Ultrastable Y), are obtained by secondary treatment of Y-type zeolite (Na-Y; GT KERR et al., “Molecular Sieves”, Vol. 121, (USA), American Chemical Society, June 1, 1973, 219-229 (see Chapter 19) can also be preferably used.

[0046] As the zeolite, various types of zeolite such as Bronsted acid type zeolite having protonic hydrogen atoms and Lewis acid type zeolite having cations of elements in Groups 3 to 15 can be used.

[0047] Proton-type zeolites having protonic hydrogen atoms are represented by HY type, H-SDUSY type, H-SUSY type, H-beta type, H-mordenite type, H-ZSM-5 type, etc. Ammonium-type zeolites, such as NH 4 -Y type, NH4 -VUSY type, NH 4 -Beta type, NH 4 -Mordenite type and NH 4 Zeolite such as ZSM-5 type can be calcined and converted into a proton type to be used as the proton type zeolite.

[0048] As the above-mentioned zeolite, various types including commercially available products can be used. Examples of USY-type zeolites include "CBV760", "CBV780", "CBV720", "CBV712" and "CBV600" manufactured by Zeolyst. Examples of Y-type zeolites include "HSZ-360HOA" and "HSZ-320HOA" manufactured by Tosoh Corporation. Examples of beta zeolites include "CP811C", "CP814N", "CP7119", "CP814E", "CP7105", "CP814CN", "CP811TL", "CP814T", "CP814Q", "CP811Q", "CP811E-75", "CP811E" and "CP811C-300" manufactured by Zeolyst Co., Ltd., and "HSZ-930HOA" and "HSZ-940HOA" manufactured by Tosoh Corporation.

[0049] A preferred example of the organic solid acid catalyst is a cation exchange resin, which may be of any of a porous type, a gel type, and a macroporous type.

[0050] Cation exchange resins include H +Polymers having acidic functional groups such as cation exchange resins of the type can be used. Examples of the acidic functional groups include sulfo groups, carboxy groups, and phosphoryl groups, and are preferably sulfo groups or carboxy groups, and more preferably sulfo groups. Examples of the polymers include Teflon (registered trademark) backbone polymers having perfluoro side chains, styrene-divinylbenzene copolymers, and (meth)acrylic acid-divinylbenzene copolymers. Note that "(meth)acrylic acid" means acrylic acid and / or methacrylic acid.

[0051] Specific examples of polymers having acidic functional groups include the Nafion series such as "Nafion NR50" (available from Fujifilm Wako Pure Chemical Industries, Ltd., Merck & Co., Inc., etc.); the Dowex series such as "Dowex 50Wx2" and "Dowex 50Wx4" (available from Fujifilm Wako Pure Chemical Industries, Ltd., Merck & Co., Inc., etc.); the Amberlite series such as "Amberlite IR-120" and "Amberlite IRP64" (available from Merck & Co., Inc., etc.); the Amberlyst series such as "Amberlyst 15(H)" and "Amberlyst 36" (available from Merck & Co., Inc., etc.); and the Purolite series such as "Purolite CT75" (available from Purolite Co., Ltd., etc.).

[0052] Of these, the cation exchange resin is preferably one or more selected from the Nafion series, the Amberlyst series, and the Dowex series, more preferably one or more selected from Nafion NR50, Amberlyst 15(H), and Dowex 50Wx2, and even more preferably Amberlyst 15(H).

[0053] The solid acid catalyst may be used alone or as a mixture of two or more kinds in any combination and in any ratio.

[0054] The amount (charge amount) of the solid acid catalyst used varies depending on the type of raw material and the type of solid acid catalyst, but is preferably k×0.1 g or more and k×100 g or less, more preferably k×0.5 g or more and k×80 g or less, and even more preferably k×1.0 g or more and k×50 g or less, relative to 1 mol of the carbonyl compound used (charge amount) (k has the same meaning as above). When the solid acid catalyst is recovered and reused after the reaction, the amount of the solid acid catalyst used is the same as above.

[0055] When the solid acid catalyst is recovered after the reaction and reused in the production of acetal, it is preferable to wash and dry the recovered solid acid catalyst prior to reuse.

[0056] An organic solvent can be suitably used for washing the solid acid catalyst. The organic solvent is not particularly limited, but preferred examples include alcohols such as methanol and ethanol; aliphatic hydrocarbons such as normal hexane and cyclohexane; and aromatic hydrocarbons such as toluene. Among these, the organic solvent is preferably alcohol, and more preferably the same type of alcohol as the raw material for acetalization.

[0057] The drying conditions for the solid acid catalyst are not particularly limited as long as the liquid adhering to the solid acid catalyst can be removed. When the solid acid catalyst is an inorganic solid acid catalyst, it is preferable to dry it at normal pressure or under reduced pressure at 100°C to 600°C for 1 hour to 48 hours. When the solid acid catalyst is an organic solid acid catalyst, it is preferable to dry it at normal pressure or under reduced pressure at 50°C to 150°C for 1 hour to 48 hours.

[0058] [1.5 Solid dehydrating agents] In this embodiment, in order to remove water that is by-produced when a carbonyl compound reacts with an alcohol to produce an acetal, the acetalization reaction is carried out in the presence of a solid dehydrating agent. By using a solid dehydrating agent as the dehydrating agent, the progress of the reverse reaction can be effectively suppressed, and the dehydrating agent can be easily separated and recovered by centrifugation, filtration, or the like after the reaction.

[0059] The solid dehydrating agent is not particularly limited, and any dehydrating agent can be used as long as it is a solid that can remove water in the reaction system and does not fall under the category of a solid acid catalyst. Examples of the optional dehydrating agent include molecular sieves, silica gel, phosphorus pentoxide, calcium chloride, magnesium sulfate, and sodium sulfate. Among these, the solid dehydrating agent is preferably a molecular sieve, and more preferably one or more selected from molecular sieve 3A and molecular sieve 4A in terms of being able to selectively remove water, and molecular sieve 3A is even more preferable. In addition, the solid dehydrating agent is preferably dried before use in order to exert sufficient dehydrating ability. For example, when the solid dehydrating agent is an inorganic solid dehydrating agent, it is preferably dried at normal pressure or reduced pressure at 100°C to 600°C for 1 hour to 48 hours before use.

[0060] The solid dehydrating agent may be used alone or in any combination of two or more kinds in any ratio.

[0061] The shape of the solid dehydrating agent is not particularly limited and may be a lump, granule, powder, etc., but in order to further increase the dehydrating ability per unit weight, a granular or powdered form is preferable. In addition, when the acetalization reaction step is carried out using a rotary reactor described below, the shape of the solid dehydrating agent is preferably a granular form in that the reaction liquid can easily flow in the cartridge.

[0062] The average particle size of the granular solid dehydrating agent is preferably 0.5 mm or more and 10 mm or less, more preferably 1.0 mm or more and 8.0 mm or less, and even more preferably 1.5 mm or more and 5.0 mm or less. The average particle size of the powdered solid dehydrating agent is preferably 10 μm or more and less than 500 μm, more preferably 30 μm or more and 300 μm or less, and further preferably 50 μm or more and 200 μm or less. In this disclosure, the term "average particle size" refers to the cumulative weight average diameter D 50 (median diameter) and is measured by a laser light scattering method.

[0063] The amount of the solid dehydrating agent used is not particularly limited as long as it can sufficiently remove water from the reaction system, and may be appropriately set depending on the dehydrating ability of the solid dehydrating agent, etc. For example, when molecular sieve 3A is used as the solid dehydrating agent, the amount of the solid dehydrating agent used (charged amount) is preferably k×5 g or more and k×250 g or less, more preferably k×20 g or more and k×200 g or less, and even more preferably k×25 g or more and k×150 g or less, relative to 1 mol of the carbonyl compound used (charged amount) (k has the same meaning as above).

[0064] [1.6 Reaction Solvent] In the acetalization reaction step, the acetalization reaction may be carried out in a reaction solvent or without a solvent. When the acetalization reaction is carried out in a reaction solvent, the concentration of each component can be easily adjusted, and the reaction is easy to control, which is preferable. On the other hand, when the pyrolysis is carried out without a solvent, the contact opportunity between the carbonyl compound and the alcohol increases, which improves the reaction rate and shortens the reaction time, and the catalytic reaction can be carried out at a lower reaction temperature, which is preferable.

[0065] In the present disclosure, "solvent-free" means that no liquid other than the reaction substrate, catalyst, product, and compounds derived therefrom is used. Therefore, for example, even if alcohol also functions as a solvent, the alcohol is not considered to be a reaction solvent, and the acetalization reaction is considered to be carried out "solvent-free."

[0066] When the acetalization reaction is carried out in a reaction solvent, the reaction solvent is preferably an inert solvent that does not react with the carbonyl compound, the solid acid catalyst, and the acetal. Preferred examples of the inert solvent include hydrocarbons and halogenated hydrocarbons.

[0067] Examples of the hydrocarbon include aliphatic hydrocarbons such as n-octane, n-nonane, n-decane, n-undecane, n-dodecane, n-tetradecane, n-octadecane, bicyclohexyl, and decalin; aromatic hydrocarbons such as benzene, toluene, ethylbenzene, butylbenzene, dodecylbenzene, o-xylene, m-xylene, p-xylene, p-cymene, naphthalene, and biphenyl; and partially hydrogenated aromatic hydrocarbons such as cyclohexylbenzene and tetralin.

[0068] Examples of halogenated hydrocarbons include 1,1,2,2-tetrachloroethane, pentachloroethane, hexachloroethane, 1,2,3-trichloropropane, o-dichlorobenzene, m-dichlorobenzene, p-dichlorobenzene, 1,2,4-trichlorobenzene, and bromobenzene.

[0069] The reaction solvent may be used alone or in any combination of two or more in any ratio.

[0070] The amount of the reaction solvent used is not particularly limited, but is preferably within a range that does not impair the reaction efficiency, and is, for example, preferably 0.1 to 100 times by volume, more preferably 0.3 to 50 times by volume, and even more preferably 0.5 to 10 times by volume, relative to the volume of the carbonyl compound.

[0071] 1.7 Reaction conditions The reaction temperature in the acetalization reaction step is not particularly limited, but is preferably from -10°C to 200°C, more preferably from 0°C to 100°C, even more preferably from 0°C to 60°C, and particularly preferably from 0°C to 35°C.

[0072] The acetalization reaction step may be carried out under normal pressure or under pressure. More specifically, the acetalization reaction step is preferably carried out at 0.1 to 100 atm, more preferably at 0.5 to 50 atm, even more preferably at 0.8 to 10 atm, and particularly preferably at 1.0 to 5 atm.

[0073] The acetalization reaction step does not require strict water-free conditions, but is preferably carried out in an inert atmosphere such as nitrogen or argon.

[0074] The reaction time in the acetalization reaction step varies depending on the reaction scale, the type of raw material, the amount of catalyst, the reaction temperature, the reaction apparatus, etc., but from the viewpoint of the acetal yield and productivity, it is preferably from 10 minutes to 48 hours, more preferably from 30 minutes to 36 hours, and even more preferably from 1 hour to 24 hours.

[0075] 1.8 Reactor The reaction apparatus for carrying out the acetalization reaction step is not particularly limited, and may be, for example, a batch reaction apparatus. Any type of device, such as a rotary type, a flow type, or a rotary type, can be used. Of these, the acetalization reaction step is preferably carried out using a rotary reactor in which a cartridge filled with a solid phase such as a solid acid catalyst is rotated and a fluid containing raw materials and the like is circulated inside and outside the cartridge to promote the reaction. Hereinafter, the rotary reactor used in the acetalization reaction step will be described with reference to the drawings.

[0076] FIG. 1(A) is an example of a perspective view that shows a rotary reactor cartridge 100, and FIG. 1(B) is a diagram that shows a rotary reactor 200 in use.

[0077] The cartridge 100 of the rotary reactor 200 has a cylindrical body 16 with a bottom and a separation wall 18 that divides the cylindrical body 16 with a bottom into a plurality of compartments. The cartridge 100 shown in FIG. 1(A) is divided into four compartments, a first compartment 11, a second compartment 12, a third compartment 13, and a fourth compartment 14, by the separation wall 18. The solid acid catalyst and the solid dehydrating agent may be mixed and filled into some or all of the compartments, but it is preferable to fill each of them into separate compartments because this makes it easier to separate and recover them after the reaction. Alternatively, one of the solid acid catalyst and the solid dehydrating agent may be filled into any compartment of the cartridge 100, and the other may be dispersed in the reaction liquid without being filled into the cartridge 100. In addition, since the main body 16 is provided with a fluid discharge port 17 for discharging the reaction liquid 25 during the reaction, a filter (not shown) is provided at the fluid discharge port 17 to prevent the solid acid catalyst and / or solid dehydrating agent from flowing out of the cartridge 100, or the solid acid catalyst and / or solid dehydrating agent is filled into the cartridge 100 via a filter (not shown).

[0078] In the following, the cartridge 100 will be described as being filled with a solid acid catalyst and a solid dehydrating agent. During the reaction, as shown in FIG. 1(B), a lid 21 and a rotating shaft 22 are attached to a cartridge 100 filled with a solid acid catalyst and a solid dehydrating agent, and the cartridge 100 is immersed in a reaction liquid 25, and a motor connected to the rotating shaft 22 rotates the cartridge 100 in the reaction liquid 25. This rotation causes the reaction liquid 25 to be sucked up from a fluid intake port (not shown) provided near the center of the bottom of the main body 16 of the cartridge 100, and the reaction liquid 25 containing the raw materials permeates the solid acid catalyst and the solid dehydrating agent, and the reaction proceeds while removing water produced as a by-product by the reaction. The reaction liquid 25 moves inside the cartridge 100, comes into contact with the solid acid catalyst and the solid dehydrating agent, and is then discharged from the fluid discharge port 17 to the outside of the cartridge 100.

[0079] The reaction liquid 25 discharged from the cartridge 100 is sucked up again into the cartridge 100 from the fluid intake port, where it comes into contact with the solid acid catalyst and the solid dehydrating agent, and the reaction and dehydration proceed. In this way, in the rotary reactor 200, the reaction liquid 25 circulates inside and outside the cartridge 100, so that the opportunities for contact between the raw material and by-product water and the solid acid catalyst and the solid dehydrating agent can be increased. Therefore, by using the rotary reactor 200 as a reaction device, the reaction rate can be improved.

[0080] In addition, by using the rotary reactor 200 and filling both the solid acid catalyst and the solid dehydrating agent into the cartridge 100 to carry out the reaction, it becomes possible to easily perform post-treatment of the reaction liquid and separate and recover the solid acid catalyst and the solid dehydrating agent without filtering the reaction liquid after the reaction.

[0081] As the rotating reactor, the reactor described in International Publication No. 2015 / 060764 and the "SpinChem roatating bed reactor RBRS2" manufactured by SpinChem can be suitably used.

[0082] [1.8 Other process equipment] The method for producing acetal according to the present embodiment includes any optional steps in addition to the acetalization reaction step. The optional step may include, for example, a purification step for increasing the purity of the acetal. As a method for purifying the acetal in the purification step, a purification method usually performed in the field of organic synthesis, such as filtration, adsorption, column chromatography, distillation, etc., can be used.

[0083] [2. Carbonate diester production system] A second embodiment of the present disclosure is a system for producing a carbonate diester, comprising: an acetal production unit that produces an acetal by reacting a carbonyl compound having either a ketonic carbonyl group or a formyl group, or both, with an alcohol in the presence of a solid acid catalyst and a solid dehydrating agent; a hydrolysis unit that hydrolyzes the acetal produced in the acetal production unit to produce a carbonyl compound having either a ketonic carbonyl group or a formyl group, or both, and an alcohol; and a carbonate diester production unit that produces a carbonate diester from a raw material including carbon dioxide and the alcohol produced in the hydrolysis unit.

[0084] Hereinafter, the carbonic acid diester production system according to this embodiment will be described with reference to FIG. In the acetal production section 31 of the carbonic acid diester production system 300, a carbonyl compound having either or both of a ketonic carbonyl group and a formyl group is reacted with an alcohol in the presence of a solid acid catalyst and a solid dehydrating agent to produce an acetal.

[0085] In this embodiment, acetal is produced by the acetal production method according to the first embodiment in the acetal production section 31. For the production of acetal, it is preferable to use the carbonyl compound and alcohol produced in the hydrolysis section 33 described later.

[0086] The acetal produced in the acetal production unit 31 is decomposed in the hydrolysis unit 33 into a carbonyl compound having either or both of a ketonic carbonyl group and a formyl group, and an alcohol. The carbonyl compound and the alcohol are the same types as the carbonyl compound and the alcohol used as raw materials for the acetal in the acetal production unit 31, respectively.

[0087] In this embodiment, the hydrolysis in the hydrolysis unit 33 is not particularly limited as long as the acetal produced in the acetal production unit 31 is used as the hydrolysis target. In addition, the acetal to be hydrolyzed may contain acetal other than the acetal produced in the acetal production unit 31. As the hydrolysis method, any method such as a known method or a method similar thereto can be used.

[0088] The alcohol produced in the hydrolysis section 33 reacts with carbon dioxide in the carbonate diester production section 35 to produce a carbonate diester and water as a by-product. The by-product water may be removed by being adsorbed onto a dehydrating agent, but it is preferable to recover it and use it for the hydrolysis of acetal in the hydrolysis section 33.

[0089] In this embodiment, the production of a carbonate diester in the carbonate diester production unit 35 is not particularly limited as long as carbon dioxide and the alcohol produced in the hydrolysis unit 33 are used as raw materials. The raw material alcohol may contain alcohol other than the alcohol produced in the hydrolysis unit 33. As a method for producing a carbonate diester, any method such as a known method or a method similar thereto can be adopted. Examples of known methods include those described in JP-A-06-262085, JP-A-07-033715, and JP-A-09-208530, or Masafumi Sugiyama et al., Chemistry-Sustainability-Energy-Materials, 2020, Examples of the method include the method described in Vol. 13, Issue 7, p. 1775-1784.

[0090] In this embodiment, as described above, the carbonyl compound and alcohol produced in the hydrolysis unit 33 are preferably used as raw materials for the acetal in the acetal production unit 31, and the water by-produced in the carbonate diester production unit 35 is preferably used for hydrolysis of the acetal in the hydrolysis unit 33. In this manner, the raw materials, products, and by-products are circulated between the various units, thereby making it possible to construct an environmentally friendly carbonate diester production system 300 that produces little waste.

[0091] 2 shows an example of a carbonate diester production system 300 including an acetal production unit 31 that produces an acetal represented by general formula (3) from a carbonyl compound represented by general formula (1) and an alcohol represented by general formula (2), but compounds that can be used in the carbonate diester production system according to this embodiment are not limited to these. Furthermore, the carbonate diester production system according to this embodiment may have a processing unit that performs any process in addition to the acetal production unit, hydrolysis unit, and carbonate diester production unit. EXAMPLES

[0092] Hereinafter, the present disclosure will be described more specifically with reference to examples. However, the present disclosure is not limited to the following examples as long as it does not deviate from the gist of the disclosure.

[0093] <Pretreatment of solid acid catalyst> HSZ-320HOA: Tosoh Corporation's Y-type zeolite "HSZ-320HOA" was calcined in an electric furnace at 500℃ for 3 hours. Nafion NR50: Fujifilm Wako Pure Chemical Corporation's "Nafion NR50" was dried under reduced pressure at 80℃ for 20 hours. Amberlyst 15DRY: "Amberlyst 15(H)" manufactured by Thermo Scientific (formerly Alfa Aesar) was dried under reduced pressure at 80℃ for 20 hours. Sulfated zirconia: Sulfated zirconia manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. was heat-treated in an electric furnace at 400°C for 10 minutes immediately before use. Dowex 50Wx2: Fujifilm Wako Pure Chemical Industries, Ltd. "Dowex 50Wx2" was dried under reduced pressure at 80℃ for 20 hours.

[0094] <Pretreatment of solid dehydrating agent> Powdered MS3A: "Synthetic Zeolite A-3" (100 mesh) manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. was dried under reduced pressure at 300℃ for 20 hours. Granular MS3A: Merck molecular sieves 0.3 nm (beads ~ 2 mm) were dried under reduced pressure at 300℃ for 20 hours.

[0095] <Reaction Apparatus> SpinChem rotating bed reactor: SpinChem rotatable bed reactor RBRS2 manufactured by SpinChem

[0096] <Analyzer> Gas chromatograph (GC) analyzer: Shimadzu GC-2014 (column: RTX) Nuclear magnetic resonance (NMR) analyzer: Bruker AVANCE 400 (solvent: C 6 D 6 )

[0097] <Calculation of yield and yield> The yield and the yield of acetal in the examples and comparative examples were calculated by GC based on the following criteria (a) or (b). (a) When the alcohol / ketone ratio is ≧2, the upper limit of the yield is determined by the amount of ketone, so the yield and yield ratio were calculated based on the ketone. (b) When the alcohol / ketone ratio is <2, the upper limit of the yield is determined by the amount of alcohol, so the yield and yield ratio were calculated based on the alcohol.

[0098] Example 1 18.4 g (0.4 molar equivalents) of ethanol and 5.8 g (0.1 molar equivalents) of acetone were added to 10 g of powdered MS3A and 1.275 g of HSZ-320HOA, and the mixture was stirred for 1 hour at 25° C. After the reaction, a portion of the solution was sampled from the reaction mixture (1a) and subjected to GC analysis. The yield of acetone diethyl acetal was calculated to be 6.6 g (yield 50%).

[0099] Example 2 18.4g (0.4 molar equivalents) of ethanol and 5.8g (0.1 molar equivalents) of acetone were added to 10g of powdered MS3A and 1.275g of HSZ-320HOA, and the mixture was stirred for 1 hour at 0°C. After the reaction, a portion of the solution was sampled from the reaction mixture and subjected to GC analysis. The yield of acetone diethyl acetal was calculated to be 3.1g (yield 23%).

[0100] Example 3 18.4 g (0.4 molar equivalents) of ethanol and 5.8 g (0.1 molar equivalents) of acetone were added to 10 g of powdered MS3A and 2.5 g of Nafion NR50, and the mixture was stirred for 2 hours at 25° C. After the reaction, a portion of the solution was sampled from the reaction mixture (3a) and subjected to GC analysis. The yield of acetone diethyl acetal was calculated to be 5.8 g (44% yield).

[0101] Example 4 18.4 g (0.4 molar equivalents) of ethanol and 5.8 g (0.1 molar equivalents) of acetone were added to 10 g of powdered MS3A and 0.1 g of Amberlyst 15DRY, and the mixture was stirred for 2 hours at 25° C. After the reaction, a portion of the solution was sampled from the reaction mixture and subjected to GC analysis. The yield of acetone diethyl acetal was calculated to be 5.4 g (41% yield).

[0102] Example 5 18.4 g (0.4 molar equivalents) of ethanol and 5.8 g (0.1 molar equivalents) of acetone were added to 10 g of powdered MS3A and 0.2 g of Amberlyst 15DRY, and the mixture was stirred for 2 hours at 25° C. After the reaction, a portion of the solution was sampled from the reaction mixture (5a) and subjected to GC analysis. The yield of acetone diethyl acetal was calculated to be 6.2 g (47% yield).

[0103] Example 6 18.4 g (0.4 molar equivalents) of ethanol and 5.8 g (0.1 molar equivalents) of acetone were added to 10 g of powdered MS3A and 1.0 g of Amberlyst 15DRY, and the mixture was stirred for 2 hours at 25° C. After the reaction, a portion of the solution was sampled from the reaction mixture and subjected to GC analysis. The yield of acetone diethyl acetal was calculated to be 5.6 g (42% yield).

[0104] Example 7 18.4 g (0.4 molar equivalents) of ethanol and 5.8 g (0.1 molar equivalents) of acetone were added to 10 g of powdered MS3A and 2.5 g of Amberlyst 15DRY, and the mixture was stirred for 2 hours at 25° C. After the reaction, a portion of the solution was sampled from the reaction mixture and subjected to GC analysis. The yield of acetone diethyl acetal was calculated to be 4.5 g (yield 34%).

[0105] Example 8 4.6 g (0.1 molar equivalent) of ethanol and 11.6 g (0.2 molar equivalent) of acetone were added to 5 g of powdered MS3A and 0.2 g of Amberlyst 15DRY, and the mixture was stirred for 2 hours at 25° C. After the reaction, a part of the solution was sampled from the reaction mixture and subjected to GC analysis. The yield of acetone diethyl acetal was calculated to be 3.0 g (45% yield).

[0106] Example 9 4.6 g (0.1 molar equivalent) of ethanol and 5.8 g (0.1 molar equivalent) of acetone were added to 5 g of powdered MS3A and 0.2 g of Amberlyst 15DRY, and the mixture was stirred for 2 hours at 25° C. After the reaction, a part of the solution was sampled from the reaction mixture and subjected to GC analysis. The yield of acetone diethyl acetal was calculated to be 3.1 g (47% yield).

[0107] Example 10 9.2g (0.2 molar equivalents) of ethanol and 5.8g (0.1 molar equivalents) of acetone were added to 10g of powdered MS3A and 0.2g of Amberlyst 15DRY, and the mixture was stirred for 2 hours at 25°C. After the reaction, a portion of the solution was sampled from the reaction mixture and subjected to GC analysis. The yield of acetone diethyl acetal was calculated to be 5.3g (40% yield).

[0108] Example 11 27.6 g (0.6 molar equivalents) of ethanol and 5.8 g (0.1 molar equivalents) of acetone were added to 10 g of powdered MS3A and 0.2 g of Amberlyst 15DRY, and the mixture was stirred for 2 hours at 25° C. After the reaction, a portion of the solution was sampled from the reaction mixture and subjected to GC analysis. The yield of acetone diethyl acetal was calculated to be 6.8 g (yield 52%).

[0109] Example 12 36.9g (0.8 molar equivalents) of ethanol and 5.8g (0.1 molar equivalents) of acetone were added to 10g of powdered MS3A and 0.2g of Amberlyst 15DRY, and the mixture was stirred for 2 hours at 25°C. After the reaction, a portion of the solution was sampled from the reaction mixture and subjected to GC analysis. The yield of acetone diethyl acetal was calculated to be 6.6g (yield 50%).

[0110] Example 13 46.1 g (1.0 molar equivalent) of ethanol and 5.8 g (0.1 molar equivalent) of acetone were added to 10 g of powdered MS3A and 0.2 g of Amberlyst 15DRY, and the mixture was stirred for 2 hours at 25° C. After the reaction, a portion of the solution was sampled from the reaction mixture and subjected to GC analysis. The yield of acetone diethyl acetal was calculated to be 6.3 g (48% yield).

[0111] Example 14 18.4g (0.4 molar equivalents) of ethanol and 5.8g (0.1 molar equivalents) of acetone were added to 5g of powdered MS3A and 0.2g of Amberlyst 15DRY, and the mixture was stirred for 2 hours at 25°C. After the reaction, a portion of the solution was sampled from the reaction mixture and subjected to GC analysis. The yield of acetone diethyl acetal was calculated to be 3.7g (yield 28%).

[0112] Example 15 18.4g (0.4 molar equivalents) of ethanol and 5.8g (0.1 molar equivalents) of acetone were added to 15g of powdered MS3A and 0.2g of Amberlyst 15DRY, and the mixture was stirred for 2 hours at 25°C. After the reaction, a portion of the solution was sampled from the reaction mixture and subjected to GC analysis. The yield of acetone diethyl acetal was calculated to be 5.6g (43% yield).

[0113] Example 16 18.4g (0.4 molar equivalents) of ethanol and 5.8g (0.1 molar equivalents) of acetone were added to 10g of powdered MS3A and 3.83g of sulfated zirconia, and the mixture was stirred for 3 hours at 25°C. After the reaction, a portion of the solution was sampled from the reaction mixture and subjected to GC analysis. The yield of acetone diethyl acetal was calculated to be 7.2g (yield 55%).

[0114] Example 17 18.4g (0.4 molar equivalents) of ethanol and 5.8g (0.1 molar equivalents) of acetone were added to 10g of powdered MS3A and 2.55g of Dowex 50Wx2, and the mixture was stirred for 1 hour at 25°C. After the reaction, a portion of the solution was sampled from the reaction mixture and subjected to GC analysis. The yield of acetone diethyl acetal was calculated to be 3.5g (yield 27%).

[0115] Example 18 18.4 g (0.4 molar equivalents) of ethanol and 7.2 g (0.1 molar equivalents) of methyl ethyl ketone were added to 10 g of powdered MS3A and 0.2 g of Amberlyst 15DRY, and the mixture was stirred for 3 hours at 25° C. After the reaction, a portion of the solution was sampled from the reaction mixture and subjected to GC analysis. The yield of methyl ethyl ketone diethyl acetal was calculated to be 6.8 g (46% yield).

[0116] Example 19 18.4 g (0.4 molar equivalents) of ethanol and 8.6 g (0.1 molar equivalents) of methyl propyl ketone were added to 10 g of powdered MS3A and 0.2 g of Amberlyst 15DRY, and the mixture was stirred for 2 hours at 25° C. After the reaction, a portion of the solution was sampled from the reaction mixture and subjected to GC analysis. The yield of methyl propyl ketone diethyl acetal was calculated to be 6.0 g (yield 38%).

[0117] Example 20 18.4 g (0.4 molar equivalents) of ethanol and 8.6 g (0.1 molar equivalents) of diethyl ketone were added to 10 g of powdered MS3A and 0.2 g of Amberlyst 15DRY, and the mixture was stirred for 24 hours at 25° C. After the reaction, a portion of the solution was sampled from the reaction mixture and subjected to GC analysis. The yield of diethyl ketone diethyl acetal was calculated to be 3.1 g (yield 19%).

[0118] Example 21 18.4 g (0.4 molar equivalents) of ethanol and 9.8 g (0.1 molar equivalents) of cyclohexanone were added to 10 g of powdered MS3A and 0.2 g of Amberlyst 15DRY, and the mixture was stirred for 24 hours at 25° C. After the reaction, a portion of the solution was sampled from the reaction mixture and subjected to GC analysis. The yield of cyclohexanone diethyl acetal was calculated to be 11.6 g (yield 67%).

[0119] Comparative Example 1 18.4 g (0.4 molar equivalents) of ethanol and 5.8 g (0.1 molar equivalents) of acetone were added to 10 g of powdered MS3A and stirred for 1 hour at 25° C. After the reaction, a portion of the solution was sampled from the reaction mixture and subjected to GC analysis, but no production of acetone diethyl acetal was observed (yield 0%).

[0120] Comparative Example 2 To 0.2 g of Amberlyst 15DRY, 18.4 g (0.4 molar equivalents) of ethanol and 5.8 g (0.1 molar equivalents) of acetone were added and stirred for 2 hours at 25° C. After the reaction, a portion of the solution was sampled from the reaction mixture and subjected to GC analysis. The yield of acetone diethyl acetal was calculated to be 0.54 g (4% yield).

[0121] Comparative Example 3 0.0058g (0.00006 molar equivalents) of concentrated sulfuric acid was added to 10g of granular MS3A, 23.0g (0.5 molar equivalents) of ethanol, and 5.8g (0.1 molar equivalents) of acetone, and the mixture was stirred for 1 hour at 25°C. After the reaction, a portion of the solution was sampled from the reaction mixture and subjected to GC analysis. The yield of acetone diethyl acetal was calculated to be 1.3g (yield 10%).

[0122] The reaction conditions and acetal yields in Examples 1 to 21 and Comparative Examples 1 to 3 are summarized in Table 1.

[0123] [Table 1]

[0124] From Table 1, it can be seen that in Examples 1 to 21, in which a solid acid catalyst and a solid dehydrating agent were used, the acetalization reaction proceeded even at temperatures of 0° C. to 25° C., and acetals were obtained in good yields. In addition, in Examples 1 to 20, an acyclic ketone was used as the carbonyl compound, and in Example 21, a cyclic ketone was used as the carbonyl compound, and it can also be seen that acetals were obtained in good yields regardless of whether the ketone was acyclic or cyclic.

[0125] On the other hand, it was confirmed that in Comparative Example 1, where a solid acid catalyst was not used, no acetal was obtained, and that in Comparative Example 1, where a solid dehydrating agent was not used, only a small amount of acetal was obtained. It was also confirmed that in Comparative Example 1, where a liquid acid catalyst was used as the catalyst, acetal could not be obtained in a good yield.

[0126] In the following, the catalytic activity of the solid acid catalyst recovered after the reaction and reused was examined.

[0127] Example 22 (Catalyst usage: 1st time) Example 1 corresponds to the first catalyst use.

[0128] (Catalyst usage: 2nd time) The solution portion was removed from the reaction mixture (1a) of Example 1 by centrifugation (400 rpm, 6 minutes), and the obtained solid was calcined at 500° C. for 3 hours. The weight of the obtained solid (22a) was 11.06 g, which was 0.98 times the total amount of powdered MS3A and HSZ-320HOA charged in Example 1. Therefore, the second experiment using the catalyst was carried out on a scale 0.98 times that of Example 1.

[0129] Specifically, 18.0 g (0.39 molar equivalents) of ethanol and 5.7 g (0.098 molar equivalents) of acetone were added to the total amount of the solid content (22a), and the mixture was stirred for 1 hour at 25° C. After the reaction, a part of the solution was sampled from the reaction mixture and subjected to GC analysis, and the yield of acetone diethyl acetal was calculated to be 3.5 g (yield 27%).

[0130] (Catalyst usage: 3rd time) The solution portion was removed from the reaction mixture obtained in the experiment using the catalyst for the second time by centrifugation (400 rpm, 6 minutes), and the obtained solid matter was calcined at 500° C. for 3 hours. The weight of the obtained solid matter (22b) was 10.8 g, which was 0.96 times the total amount of powdered MS3A and HSZ-320HOA charged in Example 1. Therefore, the experiment using the catalyst for the third time was carried out on a scale 0.96 times that of Example 1.

[0131] Specifically, 17.7 g (0.38 molar equivalents) of ethanol and 5.6 g (0.096 molar equivalents) of acetone were added to the total amount of the solid content (22b), and the mixture was stirred for 1 hour at 25° C. After the reaction, a part of the solution was sampled from the reaction mixture and subjected to GC analysis, and the yield of acetone diethyl acetal was calculated to be 0.81 g (yield 6%).

[0132] The reaction conditions and experimental results in Example 22 are shown in Table 2.

[0133] [Table 2]

[0134] Example 23 (Catalyst usage: 1st time) Example 3 corresponds to the first catalyst use.

[0135] (Catalyst usage: 2nd time) The solid matter (a mixture of powdered MS3A and Nafion NR50) was taken out by decantation from the reaction mixture (3a) of Example 3, and after drying in air, Nafion NR50 was separated using a sieve with 1 mm openings. The separated Nafion NR50 was washed three times with 20 mL of ethanol, and then dried under reduced pressure at 120° C. for 20 hours to be regenerated. The weight of the obtained regenerated Nafion NR50 (23a) was the same as the amount charged in Example 3 (2.5 g), so the experiment of the second catalyst usage was carried out on the same scale as in Example 3.

[0136] Specifically, 10 g of powdered MS3A, 18.4 g (0.4 molar equivalents) of ethanol, and 5.8 g (0.1 molar equivalents) of acetone were added to the total amount of regenerated Nafion NR50 (23a) and stirred for 2 hours at 25° C. After the reaction, a portion of the solution was taken from the reaction mixture and analyzed by GC to calculate the yield of acetone diethyl acetal.

[0137] (Catalyst usage times: 3rd to 5th) The above procedure was repeated to carry out the third, fourth, and fifth experiments using the catalyst.

[0138] The reaction conditions and experimental results in Example 23 are shown in Table 3.

[0139] [Table 3]

[0140] Example 24 (Catalyst usage: 1st time) Example 5 corresponds to the first catalyst use.

[0141] (Catalyst usage: 2nd time) The solid matter (a mixture of powdered MS3A and Amberlyst 15DRY) was removed by decantation from the reaction mixture (5a) of Example 5, and after air drying, Amberlyst 15DRY was separated using a sieve with 0.3 mm openings. The separated Amberlyst 15DRY was washed three times with 20 mL of ethanol, and then dried under reduced pressure at 120°C for 20 hours to be regenerated. The weight of the obtained regenerated Amberlyst 15DRY (24a) was 0.18 g, which was 0.89 times the amount charged in Example 5, so the second experiment of catalyst usage was carried out on a scale 0.89 times that of Example 5.

[0142] Specifically, the entire amount of recycled Amberlyst 15DRY(24a) was mixed with powdered MS3A. 8.9 g, 16.4 g (0.356 molar equivalents) of ethanol, and 5.2 g (0.089 molar equivalents) of acetone were added and stirred for 2 hours at 25° C. After the reaction, a portion of the solution was sampled from the reaction mixture and subjected to GC analysis to calculate the yield of acetone diethyl acetal.

[0143] (Catalyst usage times: 3rd to 5th) The above procedure was repeated to carry out the third, fourth, and fifth experiments using the catalyst.

[0144] The reaction conditions and experimental results in Example 24 are shown in Table 4.

[0145] [Table 4]

[0146] Example 25 (Catalyst usage: 1st time) Three of the four compartments of the cartridge of the SpinChem rotary reactor shown in Figure 1 were filled with 10 g of granular MS3A in three separate portions, and the remaining compartment was filled with 5.1 g of Nafion NR50, after which a specified lid and rotating shaft were attached. 18.4 g (0.4 molar equivalents) of ethanol and 5.8 g (0.4 molar equivalents) of acetone were placed in a beaker, and the cartridge was inserted from above. The rotating shaft was then connected to a motor and rotated at 200 rpm for 24 hours to stir. After the reaction, a portion of the solution was sampled and analyzed by GC, and the yield of acetone diethyl acetal was calculated to be 2.6 g (20% yield).

[0147] (Catalyst usage: 2nd time) After the first reaction run, remove the cartridge from the SpinChem rotating reactor. The Nafion NR50 was collected using tweezers. It was then washed three times with 20 mL of ethanol and then dried under reduced pressure at 120°C for 20 hours to be regenerated. This regenerated Nafion NR50 (5.1 g) was used to carry out the second catalyst use experiment.

[0148] Specifically, 10 g of granular MS3A was divided into three and filled into three of the four compartments of the cartridge of the SpinChem rotary reactor, and the remaining compartment was filled with the entire amount of regenerated Nafion NR50 and fitted with a specified lid. 18.4 g (0.4 molar equivalents) of ethanol and 5.8 g (0.4 molar equivalents) of acetone were placed in a beaker, and the cartridge was inserted from above. The rotating shaft was then connected to a motor and rotated at 200 rpm for 20 hours to stir. After the reaction, a portion of the solution was sampled and subjected to GC analysis, and the yield of acetone diethyl acetal was calculated.

[0149] (Catalyst usage times: 3rd to 5th) The above procedure was repeated to carry out the third, fourth, and fifth experiments using the catalyst.

[0150] The reaction conditions and experimental results in Example 25 are shown in Table 5.

[0151] [Table 5]

[0152] Example 26 (Catalyst usage: 1st time) Granular MS3A (10 g) and Amberlyst 15DRY (1.0 g) were evenly filled and mixed in the four compartments of the cartridge of the SpinChem rotary reactor shown in Figure 1, and the designated lid and rotating shaft were attached. 18.4 g (0.4 molar equivalents) of ethanol and 5.8 g (0.4 molar equivalents) of acetone were placed in a beaker, and the cartridge was inserted from above. The rotating shaft was then connected to a motor and rotated at 200 rpm for 24 hours. After the reaction, a portion of the solution was sampled and analyzed by GC, and the yield of acetone diethyl acetal was calculated to be 4.1 g (31% yield).

[0153] (Catalyst usage: 2nd time) After the first reaction, the cartridge was removed from the SpinChem rotary reactor, the contents of the cartridge were air-dried, and then sieved through a 0.3 mm sieve to separate Amberlyst Amberlyst 15DRY was separated. The separated Amberlyst 15DRY was washed three times with 20 mL of ethanol, and then dried under reduced pressure at 120°C for 20 hours to be regenerated. This regenerated Amberlyst 15DRY (1.0 g) was used in the second experiment of catalyst use.

[0154] Specifically, 10 g of granular MS3A and the entire amount of regenerated Amberlyst 15DRY were evenly filled into the four compartments of a cartridge of a SpinChem rotary reactor, mixed, and the specified lid and rotating shaft were attached. 18.4 g (0.4 molar equivalents) of ethanol and 5.8 g (0.4 molar equivalents) of acetone were placed in a beaker, and the cartridge was inserted from above. The cartridge was then rotated at 200 rpm by a motor and stirred for 24 hours. After the reaction, a portion of the solution was collected and analyzed by GC, and the yield of acetone diethyl acetal was calculated.

[0155] (Catalyst usage times: 3rd to 5th) The above procedure was repeated to carry out the third, fourth, and fifth experiments using the catalyst.

[0156] The reaction conditions and experimental results in Example 26 are shown in Table 6.

[0157] [Table 6]

[0158] Comparing Example 22, which uses an inorganic solid acid catalyst, with Examples 23 to 25, which use an organic solid acid catalyst, it is found that the organic solid acid catalyst has better reusability than the inorganic solid acid catalyst. In addition, it was confirmed that the cation exchange resin, which is an organic solid acid catalyst, can maintain catalytic activity equivalent to that of the first reaction even when the cycle of recovery and reuse after the reaction is repeated multiple times. Therefore, when used in combination with a rotary reactor and an organic solid acid catalyst, it is possible to demonstrate the ease of recovery and reusability of the catalyst, and it is considered to be useful in the field of organic synthesis. [Industrial Applicability]

[0159] According to the present disclosure, there is provided a novel method for producing an acetal from a carbonyl compound and an alcohol using a solid acid catalyst and a solid dehydrating agent.

[0160] Furthermore, by applying this acetal production method to a carbonate diester production system, it is possible to provide an environmentally friendly carbonate diester production system that produces little waste. [Explanation of symbols]

[0161] 11 Section 1 12 Section 2 13 Section 3 14 Section 4 16 Main unit 17 Fluid outlet 18 Separation wall 100 cartridges 21 Lid 22 Rotation axis 25 Reaction solution 200 Rotating Reactor 31 Acetal Manufacturing Department 33 Hydrolysis section 35 Carbonate Diester Manufacturing Department 300 Carbonate diester production system

Claims

1. A method for producing an acetal, comprising an acetalization reaction step of reacting a carbonyl compound having either a ketonic carbonyl group or a formyl group, or both, with an alcohol in the presence of a solid acid catalyst and a solid dehydrating agent.

2. The carbonyl compound is a compound represented by general formula (1), The method for producing an acetal according to claim 1, wherein the alcohol is a compound represented by general formula (2): 【Chemistry 1】 R ３ OH (2) (In the general formula, R １ is an aliphatic hydrocarbon group which may have a substituent; R ２ represents an optionally substituted aliphatic hydrocarbon group or a hydrogen atom; R ３ is an aliphatic hydrocarbon group which may have a substituent; R １ and R ２ When both are aliphatic hydrocarbon groups, R １ and R ２ may be bonded to each other via a single bond or a linking group to form a ring.

3. The method for producing an acetal according to claim 1 , wherein the solid acid catalyst is a cation exchange resin.

4. The method for producing acetals according to claim 1, wherein the solid dehydrating agent is a molecular sieve.

5. The method for producing an acetal according to claim 1, wherein the acetalization reaction step is carried out using a rotary reactor having a cartridge filled with one or more selected from the group consisting of the solid acid catalyst and the solid dehydrating agent.

6. an acetal production unit that produces an acetal by reacting a carbonyl compound having either or both of a ketonic carbonyl group and a formyl group with an alcohol in the presence of a solid acid catalyst and a solid dehydrating agent; a hydrolysis section for hydrolyzing the acetal produced in the acetal production section to produce a carbonyl compound having either or both of a ketonic carbonyl group and a formyl group, and an alcohol; a carbonic acid diester production section for producing a carbonic acid diester from a raw material containing carbon dioxide and the alcohol produced in the hydrolysis section; A system for producing a carbonate diester comprising:

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