Method for producing carbonic acid diester

Abstract

Disclosed is a method for producing a carbonic acid diester, the method comprising a reaction step in which a carbonic acid monoester salt and an alkoxysilane are reacted with each other in the presence of one or more catalysts that are selected from the group consisting of cerium catalysts and tin catalysts.

Description

Carbonate diester manufacturing method

[0001] The present disclosure relates to a method for producing a carbonic acid diester.

[0002] Carbonate diesters are widely used as solvents for electrolytes and the like, alkylating agents, carbonylating agents, gasoline additives, diesel fuel additives, and raw materials for polymers such as polycarbonates.

[0003] As a method for producing a carbonate diester, a method of reacting phosgene with an alcohol is widely known and has been industrialized. However, this method has problems such as corrosion of the equipment due to the by-product hydrochloric acid and the need to use phosgene, which is highly toxic and corrosive. Therefore, development of a technology for producing a carbonate diester without using phosgene has been promoted.

[0004] Patent Document 1 discloses a method for producing an organic carbonate by reacting an alcohol, carbon dioxide, and an alkyl halide in an ionic liquid.

[0005] Non-Patent Document 1 discloses a method for producing dimethyl carbonate by dissolving an ionic liquid saturated with carbon dioxide, adding methyl iodide, and performing electrochemical reduction using an NPC-Ag electrode.

[0006] Chinese Patent Application Publication No. 111362800

[0007] Chinese Chemical Letters, 2010, 987-990

[0008] Although the methods described in Patent Document 1 and Non-Patent Document 1 do not require the use of phosgene, they do require the use of methyl iodide and alkyl halide as sacrificial reagents, respectively. These sacrificial reagents have a large environmental impact, and in recent years, when efforts to address environmental issues have become increasingly important, reducing the amount of use of these sacrificial reagents has become a social issue.

[0009] An object of the present disclosure is to provide a novel method for producing carbonic acid diesters without using sacrificial reagents such as alkyl halides and phosgene.

[0010] As a result of intensive research aimed at solving the above-mentioned problems, the present inventors have found that a carbonate diester can be produced without using a sacrificial reagent such as an alkyl halide or phosgene by reacting a carbonate monoester salt with an alkoxysilane in the presence of a catalyst.

[0011] [1] A method for producing a carbonate diester, comprising a reaction step of reacting a carbonate monoester salt with an alkoxysilane in the presence of one or more catalysts selected from the group consisting of a cerium catalyst and a tin catalyst. [2] The method for producing a carbonate diester according to [1], wherein the carbonate monoester salt is a compound represented by general formula (1), the alkoxysilane is a compound represented by general formula (2), and the carbonate diester is a compound represented by general formula (3). (In the general formula, R １ are each independently a substituted or unsubstituted hydrocarbon group; R ２ are each independently a substituted or unsubstituted hydrocarbon group; A ｍ＋ is an m-valent cation derived from a base represented by A; m is 1 or 2; p is an integer of 1 to 4; when p is 1 or 2, a plurality of R ２ may be linked to each other to form a ring. １ is a substituted or unsubstituted aliphatic hydrocarbon group. [4] The method for producing a carbonate diester according to [2] or [3], wherein p is 2 or more and 4 or less. [5] The method for producing a carbonate diester according to any of [1] to [4], wherein the reaction step is carried out under a temperature condition of 80°C or more and 250°C or less. [6] The method for producing a carbonate diester according to any of [1] to [5], wherein the cerium catalyst is cerium (IV) oxide. [7] The method for producing a carbonate diester according to any of [1] to [6], wherein the tin catalyst is one or more selected from the group consisting of dialkyltin dialiphatic monocarboxylic acids and dialkyltin oxides. [8] The method for producing a carbonate diester according to any of [1] to [6], comprising, before the reaction step, a carbonate monoester salt production step of contacting an alcohol, a base, and a carbon dioxide-containing gas,ｔ The partial pressure P of the carbon dioxide gas in the carbon dioxide-containing gas ＣＯ２ [9] The method for producing a carbonic acid diester according to any one of [1] to [7], wherein the ratio of the partial pressure P of the carbon dioxide gas in the carbon dioxide-containing gas is 0.0001 or more and 1.00 or less. ＣＯ２ The method for producing a carbonate diester according to [8], wherein the pressure is less than 0.100 MPa.

[0012] According to the present disclosure, a novel method for producing a carbonic acid diester can be provided without using a sacrificial reagent such as an alkyl halide or phosgene.

[0013] The present disclosure will be described in detail below, but the description of the constituent elements described below is an example (typical example) of an embodiment of the present disclosure, and the present disclosure is not limited to these contents and can be implemented with various modifications within the scope of the gist. In the present disclosure, a term such as "one or more selected from the group consisting of X, Y, and Z" means any of X, Y, Z, a combination of X and Y, a combination of X and Z, a combination of Y and Z, or a combination of X, Y, and Z. In the present disclosure, a term such as "X or more and Y or less" and "X to Y" representing a numerical range means a numerical range including the lower and upper limits, which are the endpoints, unless otherwise specified. In the present disclosure, a term such as "X, x2, and x3" means that x1, x2, and x3 are listed as examples of X, and does not mean that X is limited to x1, x2, x3, etc.

[0014] A method for producing a carbonate diester according to one embodiment of the present disclosure includes a reaction step of reacting a carbonate monoester salt with an alkoxysilane in the presence of one or more catalysts selected from the group consisting of cerium catalysts and tin catalysts. The production method according to this embodiment is a method for producing a carbonate diester using a carbonate monoester salt as a raw material, and does not require the use of phosgene as a raw material. Furthermore, in the production method according to this embodiment, the reaction proceeds under relatively low temperature conditions without the use of a sacrificial reagent, and a carbonate diester is produced. In other words, the production method according to this embodiment is an environmentally friendly production method that can reduce production costs and is highly energy efficient, and therefore has high industrial utility value.

[0015] According to the production method of this embodiment, a carbonate diester can be produced without using a sacrificial reagent and phosgene, but in the present disclosure, "without using a sacrificial reagent and phosgene" means that it is not necessary to use a sacrificial reagent and phosgene, and although it is preferable not to use a sacrificial reagent and phosgene, it is not intended to exclude all embodiments in which either or both of a sacrificial reagent and phosgene are used. For example, when the production method of this embodiment includes a step of producing a carbonate monoester salt, this step may be a step of producing a carbonate monoester salt using phosgene as a raw material.

[0016] 1. Reaction Step In the reaction step, a carbonate monoester salt and an alkoxysilane are reacted in the presence of one or more catalysts selected from the group consisting of cerium catalysts and tin catalysts to produce a carbonate diester.

[0017] 1-1. Carbonate Monoester Salt The carbonate monoester salt is not particularly limited and can be appropriately selected depending on the target carbonate diester. The carbonate monoester salt may be used alone or in any combination and ratio of two or more kinds.

[0018] In this embodiment, the carbonate monoester salt is preferably a compound represented by general formula (1).

[0019]

[0020] (R １ ) R １ are each independently a substituted or unsubstituted hydrocarbon group. In the present disclosure, the hydrocarbon group includes an aliphatic hydrocarbon group and an aromatic hydrocarbon group. The aliphatic hydrocarbon group is not limited to a linear hydrocarbon group, and may have a branched structure, a carbon-carbon unsaturated bond, or a cyclic structure. The aromatic hydrocarbon group may be a monocyclic, polycyclic, or fused ring type, or may be a heterocyclic aromatic hydrocarbon group.

[0021] R １ The number of carbon atoms in the hydrocarbon group represented by the formula (I) is not particularly limited. When the hydrocarbon group is an aliphatic hydrocarbon group, the number of carbon atoms is usually 1 or more, preferably 2 or more, and usually 30 or less, preferably 24 or less, more preferably 12 or less, and even more preferably 8 or less. That is, suitable ranges for the number of carbon atoms in the aliphatic hydrocarbon group include 1 or more and 30 or less, 1 or more and 24 or less, 2 or more and 12 or less, and 2 or more and 8 or less. When the hydrocarbon group is an aromatic hydrocarbon group, the number of carbon atoms is usually 3 or more, preferably 6 or more, and usually 30 or less, preferably 24 or less, and more preferably 20 or less. That is, suitable ranges for the number of carbon atoms in the aromatic hydrocarbon group include 3 or more and 30 or less, 6 or more and 24 or less, and 6 or more and 20 or less. In the present disclosure, when the hydrocarbon group has a substituent, the number indicated as the number of carbon atoms in the hydrocarbon group includes the number of carbon atoms of the substituent.

[0022] Examples of the unsubstituted aliphatic hydrocarbon group 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, an n-nonyl group, an n-decyl group, 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-octadecy ... alkyl groups such as a cyclopropyl group, an n-nonadecyl group, and an n-docosyl group; cycloalkyl groups such as a cyclopropyl group, an n-cyclobutyl group, an n-cyclopentyl group, and an n-cyclohexyl group; alkenyl groups such as a vinyl group, an allyl group, a 1-propenyl group, an isopropenyl group, a 1-butenyl group, a 2-butenyl group, a 2-methylallyl group, a 1-hexenyl group, a 1-heptenyl group, a 1-octenyl group, and a 2-methyl-1-propenyl group; and alkynyl groups such as a propargyl group.

[0023] Examples of the unsubstituted aromatic hydrocarbon group include a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a 1-phenanthryl group, a 2-phenanthryl group, a 3-phenanthryl group, a 4-phenanthryl group, a 9-phenanthryl group, a 1-anthryl group, a 2-anthryl group, a 9-anthryl group, a 1-pyrenyl group, a 2-pyrenyl group, a 4-pyrenyl group, a 1-triphenylenyl group, a 2-triphenylenyl group, a 2-pyridyl group, a 3-pyridyl group, and a 4-pyridyl group.

[0024] R １When the hydrocarbon group represented by the formula (I) has a substituent, the substituent may be a deuterium atom; an alkyl group having 1 to 4 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, or a tert-butyl group; a cycloalkyl group having 3 to 6 carbon atoms, such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, or a cyclohexyl group; an aromatic hydrocarbon group having 6 to 10 carbon atoms, such as a phenyl group, a 1-naphthyl group, or a 2-naphthyl group; a halogen group such as a fluoro group, a chloro group, a bromo group, or an iodo group; oxygen-containing functional groups such as an alkoxy group, a carboxy group, a carbonyl group, and a hydroxyl group having from 1 to 4 carbon atoms; nitrogen-containing functional groups such as a cyano group; sulfur-containing functional groups such as an alkylthio group; functional groups containing oxygen atoms and nitrogen atoms such as an amide group, an imide group, a urea group, a group containing a urethane structure, a group containing an isocyanuric structure, a nitro group, a nitroso group, a cyanate group, an isocyanate group, and a morpholino group; oxygen-containing heterocyclic groups such as a furanyl group; sulfur-containing heterocyclic groups such as a thienyl group; and nitrogen-containing heterocyclic groups such as a pyrrolyl group and a pyridyl group.

[0025] R １ When the hydrocarbon group represented by the formula (I) has a substituent, R １ Preferred examples of the alkyl group include alkyl-substituted phenyl groups such as a 2-methylphenyl group, a 3-methylphenyl group, and a 4-methylphenyl group; alkoxy-substituted phenyl groups such as a 2-methoxyphenyl group, a 3-methoxyphenyl group, and a 4-methoxyphenyl group; halogen-substituted phenyl groups such as a 2-chlorophenyl group, a 3-chlorophenyl group, a 4-chlorophenyl group, a 2-bromophenyl group, a 3-bromophenyl group, and a 4-bromophenyl group; nitro-substituted phenyl groups such as a 4-nitrophenyl group and a 2-nitrophenyl group; aromatic-substituted alkyl groups such as a benzyl group, a phenethyl group, a 1-naphthylmethyl group, and a 2-naphthylmethyl group; cycloalkyl-substituted alkyl groups such as a cyclohexylmethyl group; hydrocarbon groups having an oxygen-containing heterocycle such as a furfuryl group; hydrocarbon groups having a sulfur-containing heterocycle such as a thienylmethyl group; and hydrocarbon groups having a nitrogen-containing heterocycle such as a pyridylmethyl group.

[0026] Among the above hydrocarbon groups, R １is preferably an aliphatic hydrocarbon group, more preferably a substituted or unsubstituted aliphatic hydrocarbon group having from 1 to 24 carbon atoms, even more preferably an alkyl group having from 1 to 24 carbon atoms, still more preferably an alkyl group having from 1 to 12 carbon atoms, particularly preferably an alkyl group having from 1 to 4 carbon atoms, and most preferably an alkyl group having from 1 to 2 carbon atoms. １ may be the same group or different groups, but are preferably the same group.

[0027] (A ｍ＋ and m) A ｍ＋ is an m-valent cation derived from a base represented by A. Furthermore, m is 1 or 2, and preferably 1.

[0028] A ｍ＋ is not particularly limited, and is preferably, for example, one or more cations selected from the group consisting of ammonium cation, amidinium cation, guanidinium cation, phosphonium cation, phosphazenium cation, carbocation, Group 1 metal cation, and Group 2 metal cation.

[0029] Examples of ammonium cations include primary ammonium cations such as methylammonium cation, ethylammonium cation, isopropylammonium cation, n-butylammonium cation, and 2-hydroxyethylammonium cation; secondary ammonium cations such as dimethylammonium cation, diethylammonium cation, and dicyclohexylammonium cation; tertiary ammonium cations such as trimethylammonium cation and triethylammonium cation; and quaternary ammonium cations such as tetramethylammonium cation, tetraethylammonium cation, tetrapropylammonium cation, tetrabutylammonium cation, phenyltrimethylammonium cation, and benzyltrimethylammonium cation.

[0030] Examples of the amidinium cation include a formamidinium cation in which formamidine is protonated, an acetamidinium cation in which acetamidine is protonated, a 1,5-diazabicyclo[4.3.0]non-5-enium cation in which 1,5-diazabicyclo[4.3.0]non-5-ene is protonated, a 1,8-diazabicyclo[5.4.0]undec-7-enium cation in which 1,8-diazabicyclo[5.4.0]undec-7-ene is protonated, and derivatives in which a substituent has been introduced into these. Examples of the substituent include R １ Examples of the substituent that the hydrocarbon group represented by the following formula may have include those described above.

[0031] Examples of the guanidinium cation include a 1,1,3,3-tetramethylguanidinium cation in which 1,1,3,3-tetramethylguanidine is protonated, a 2-tert-butyl-1,1,3,3-tetramethylguanidinium cation in which 2-tert-butyl-1,1,3,3-tetramethylguanidinium is protonated, a 1,5,7-triazabicyclo[4.4.0]dec-5-enium cation in which 1,5,7-triazabicyclo[4.4.0]dec-5-ene is protonated, a 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-enium cation in which 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene is protonated, and derivatives in which a substituent has been introduced into these. Examples of the substituent include R １ Examples of the substituent that the hydrocarbon group represented by the following formula may have include those described above.

[0032] Examples of phosphonium cations include tertiary phosphonium cations such as triphenylphosphonium cation and tri-tert-butylphosphonium cation; and quaternary phosphonium cations such as tetraphenylphosphonium cation, tetra-p-tolylphosphonium cation, triphenylbenzylphosphonium cation, triphenylbutyl cation, tetraethylphosphonium cation, and tetrabutylphosphonium cation.

[0033] Examples of phosphazenium cations include tert-butylimino-tris(dimethylamino)phosphoranes obtained by protonating tert-butylimino-tris(dimethylamino)phosphoranes, tert-butylimino-tris(pyrrolidino)phosphoranes obtained by protonating tert-butylimino-tris(pyrrolidino)phosphoranes, 2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorinium cations obtained by protonating 2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorinium cations, and 1-tert-butyl-2,2,4,4,4-pentakis(dimethylamino)-2λ ５ , 4λ ５ - Catenadi(phosphazene) protonated, 1-tert-butyl-2,2,4,4,4-pentakis(dimethylamino)-2λ ５ , 4λ ５ -catenadi(phosphazenium) cation, 1-tert-butyl-4,4,4-tris(dimethylamino)-2,2-bis[tris(dimethylamino)phosphoranylideneamino]-2λ ５ , 4λ ５ - Catenadi(phosphazene) protonated 1-tert-butyl-4,4,4-tris(dimethylamino)-2,2-bis[tris(dimethylamino)phosphoranylideneamino]-2λ ５ , 4λ ５ -catenadi(phosphazenium) cations and derivatives thereof into which a substituent has been introduced. １ Examples of the substituent that the hydrocarbon group represented by the following formula may have include those described above.

[0034] Examples of carbocations include monovalent carbocations such as triphenylmethyl cation, tropylium cation, and azulenium cation.

[0035] Examples of Group 1 metal cations include lithium cations, sodium cations, and potassium cations.

[0036] Examples of Group 2 metal cations include magnesium cations and calcium cations.

[0037] A ｍ＋ From the viewpoints of ease of availability of A and the yield of the carbonate diester, is preferably a cation selected from the group consisting of ammonium cation, amidinium cation, guanidinium cation, phosphonium cation, phosphazenium cation, and carbocation, more preferably a cation selected from the group consisting of ammonium cation, amidinium cation, guanidinium cation, phosphonium cation, and phosphazenium cation, even more preferably a cation selected from the group consisting of amidinium cation and guanidinium cation, and particularly preferably an amidinium cation.

[0038] Specific examples of the compound represented by general formula (1) include compounds represented by the following formulas and amidinium salts, guanidinium salts, phosphonium salts, phosphazenium salts, carbocation salts, Group 1 metal salts, and Group 2 metal salts, in which the counter cation is an amidinium cation other than 1,8-diazabicyclo[5.4.0]undec-7-enium cation, a guanidinium cation, a phosphonium cation, a phosphazenium cation, a carbocation, a Group 1 metal cation, or a Group 2 metal cation.

[0039]

[0040] The carbonate monoester salt may be a commercially available product, may be produced by a known production method or a method similar thereto, or may be produced by the carbonate monoester salt production step described below. In the carbonate monoester salt production step described below, a carbonate monoester salt can be produced without using phosgene or a sacrificial reagent, so the carbonate monoester salt is preferably produced by such a step.

[0041] The amount of carbonate monoester salt used in the reaction step (charge amount; total amount when multiple types are used) is not particularly limited, but in this embodiment, since it is believed that a carbonate diester is produced by the reaction of two molecules of alkoxysilane with one molecule of carbonate monoester salt. Therefore, the amount is preferably 0.1 equivalents or more and 0.5 equivalents or less relative to the alkoxysilane. In the present disclosure, "equivalent" means chemical equivalent (molar equivalent).

[0042] 1-2. Alkoxysilane The alkoxysilane is not particularly limited and can be appropriately selected depending on the target carbonate diester. In this disclosure, alkoxysilane refers to alkoxysilane and its derivatives. The alkoxysilane may be used alone or in any combination and ratio of two or more types.

[0043] In this embodiment, the alkoxysilane is preferably a compound represented by general formula (2): Si(OR １ ) ｐ (R ２ ) ４－ｐ (2)

[0044] (R １ ) R １ is a substituted or unsubstituted hydrocarbon group. １ represents R in general formula (1). １ When p is 2 or more and 4 or less, a plurality of R １ may be the same group or different groups. １ represents R in general formula (1). １ may be the same group as or different from, but from the viewpoint of efficiently producing a single carbonate diester, they are preferably the same group.

[0045] (R ２ ) R ２ is a substituted or unsubstituted hydrocarbon group. ２ is R １When p is 1 or 2, the plural R ２ may be the same group or different groups. ２ From the viewpoint of availability and stability of the alkoxysilane, R is preferably a methyl group, an ethyl group, a vinyl group, an allyl group, or a phenyl group. ２ When the hydrocarbon group represented by the formula (I) has a substituent, suitable substituents include an isocyanate group and a cyano group.

[0046] (p) p is an integer of 1 or more and 4 or less, and from the viewpoint of reaction efficiency, it is preferably an integer of 2 or more and 4 or less, more preferably an integer of 3 or more and 4 or less, and even more preferably 4.

[0047] That is, the alkoxysilane represented by general formula (2) is a compound selected from the group consisting of monoalkoxysilane, dialkoxysilane, trialkoxysilane, and tetraalkoxysilane, preferably a compound selected from the group consisting of dialkoxysilane, trialkoxysilane, and tetraalkoxysilane, more preferably a compound selected from the group consisting of trialkoxysilane and tetraalkoxysilane, and even more preferably a tetraalkoxysilane.

[0048] Specific examples of monoalkoxysilanes include methoxytrimethylsilane, methoxytriethylsilane, methoxytripropylsilane, methoxytriisobutylsilane, methoxytrioctylsilane, methoxytrihexadecylsilane, methoxytrivinylsilane, methoxytriphenylsilane, phenylmethoxydimethylsilane, phenylmethoxydiethylsilane, ethoxytrimethylsilane, ethoxytriethylsilane, ethoxytripropylsilane, ethoxytriisobutylsilane, ethoxytrioctylsilane, ethoxytriphenylsilane, ethoxytrivinylsilane, ethoxytriallylsilane, ethoxydiethylphenylsilane, phenylethoxydipropylsilane, propoxytrimethylsilane, propoxytriethylsilane, propoxytripropylsilane, phenylpropoxydimethylsilane, phenylpropoxydiethylsilane, and phenylpropoxydipropylsilane. Among these, the monoalkoxysilane is preferably ethoxytrimethylsilane from the viewpoints of availability and reactivity.

[0049] Specific examples of dialkoxysilanes include dimethoxydimethylsilane, dimethoxydiethylsilane, dimethoxydipropylsilane, phenyldimethoxymethylsilane, dimethoxymethylvinylsilane, dimethoxydiphenylsilane, diethoxydimethylsilane, diethoxydiethylsilane, diethoxydipropylsilane, diethoxymethylphenylsilane, diethoxyethylphenylsilane, diethoxyphenylpropylsilane, dipropoxydimethylsilane, dipropoxydiethylsilane, dipropoxydipropylsilane, phenyldipropoxymethylsilane, phenyldipropoxyethylsilane, phenyldipropoxypropylsilane, dibutoxydimethylsilane, dibutoxydiethylsilane, and phenyldimethoxyethylsilane. Of these, the dialkoxysilane is preferably a compound selected from the group consisting of dimethoxydimethylsilane and diethoxydimethylsilane, from the standpoints of availability and reactivity.

[0050] Specific examples of trialkoxysilanes include trimethoxymethylsilane, trimethoxyethylsilane, trimethoxypropylsilane, trimethoxyisobutylsilane, trimethoxyoctylsilane, trimethoxyhexadecylsilane, triethoxymethylsilane, triethoxyethylsilane, triethoxypropylsilane, triethoxyisobutylsilane, triethoxyoctylsilane, trimethoxyvinylsilane, trimethoxyphenylsilane, triethoxyphenylsilane, triethoxyvinylsilane, triethoxyallylsilane, tripropoxymethylsilane, tripropoxyethylsilane, tripropoxypropylsilane, tripropoxyphenylsilane, 2-cyanoethyltriethoxysilane, and (3-isocyanatopropyl)triethoxysilane. Of these, from the viewpoints of availability and reactivity, the trialkoxysilane is preferably a compound selected from the group consisting of trimethoxymethylsilane, triethoxymethylsilane, triethoxyphenylsilane, triethoxyvinylsilane, and triethoxyallylsilane.

[0051] Specific examples of tetraalkoxysilanes include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraisopropoxysilane, tetrabutoxysilane, and tetrakis(2-ethylhexyloxy)silane. Of these, from the viewpoints of availability and reactivity, the tetraalkoxysilane is preferably a compound selected from the group consisting of tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane, and more preferably tetraethoxysilane.

[0052] 1-3. Catalyst In the reaction step, one or more catalysts selected from the group consisting of cerium catalysts and tin catalysts are used as catalysts for the reaction of the carbonate monoester salt with the alkoxysilane.

[0053] The cerium catalyst is not particularly limited, and examples thereof include cerium(IV) oxide, cerium(IV) sulfate, cerium(IV) fluoride, cerium(IV) trifluoromethanesulfonate, cerium(III) fluoride, cerium(III) chloride, cerium(III) bromide, cerium(III) iodide, cerium(III) acetate, cerium stearate, cerium carbonate, cerium(III) trifluoromethanesulfonate, cerium(III) tungstate, cerium(III) oxalate, and cerium(III) phosphate. Preferably, the cerium catalyst is at least one selected from the group consisting of cerium(IV) oxide, cerium(IV) sulfate, cerium(IV) fluoride, and cerium(IV) trifluoromethanesulfonate, and particularly preferably cerium(IV) oxide.

[0054] The tin catalyst is not particularly limited, and examples thereof include dialkyltin dialiphatic monocarboxylic acids such as dimethyltin dilaurate, dibutyltin dilaurate, dibutyltin maleate, dibutyltin diacetate, and dioctyltin dilaurate; dialkyltin oxides such as dibutyltin oxide and dibutyltin oxide; and dialkyltin dihalides such as dibutyltin dichloride and dibutyltin dibromide; and preferably at least one selected from the group consisting of dialkyltin dialiphatic monocarboxylic acids and dialkyltin oxides.

[0055] Of these, from the viewpoint of catalytic activity, the catalyst is preferably one or more selected from the group consisting of cerium (IV) oxide, dialkyltin dialiphatic monocarboxylic acid, and dialkyltin oxide, more preferably one or more selected from the group consisting of cerium (IV) oxide, dibutyltin dilaurate, and dibutyltin oxide, and even more preferably cerium (IV) oxide.

[0056] The amount of catalyst used in the reaction step (charge amount; total amount when multiple types are used) may be appropriately selected depending on the type of carbonate monoester salt, the type of alkoxysilane, and the type of catalyst. Specifically, the amount of catalyst used is preferably 0.5 mol% or more, more preferably 1.0 mol% or more, even more preferably 5.0 mol% or more, and particularly preferably 10.0 mol% or more, relative to the alkoxysilane, and is usually 70.0 mol% or less, preferably 50.0 mol% or less, more preferably 40.0 mol% or less, and even more preferably 30.0 mol% or less. That is, suitable ranges of the amount of catalyst used include, for example, 0.5 mol% or more and 70.0 mol% or less, 1.0 mol% or more and 50.0 mol% or less, 5.0 mol% or more and 40.0 mol% or less, and 10.0 mol% or more and 30.0 mol% or less.

[0057] 1-4. Reaction mechanism The present inventors speculate that the reaction mechanism by which a carbonate diester is produced by the production method according to this embodiment is as shown in the following scheme. The following scheme is an example in which a compound represented by general formula (1) in which m is 1 is used as the carbonate monoester, and a compound represented by general formula (2) in which p is 4 (i.e., tetraalkoxysilane) is used as the alkoxysilane. As shown in the scheme below, it is speculated that in the production method according to this embodiment, one molecule of carbonate monoester salt and two molecules of alkoxysilane are consumed to produce one molecule of carbonate diester. Furthermore, in the scheme below, the OR of the carbonate monoester １ OR group and alkoxysilane １ The OR group is exchanged with the carbonate monoester. １ OR derived from diester carbonate and monoester carbonate having two groups １ OR groups derived from alkoxysilanes １ and a carbonate diester having an OR group derived from an alkoxysilane. １ It is believed that difunctional carbonate diesters may occur.

[0058]

[0059] 1-5. Carbonate diester The carbonate diester produced by the production method according to this embodiment is a carbonate diester having two ester groups selected from the group consisting of an ester group derived from a carbonate monoester salt and an ester group derived from an alkoxy group of an alkoxysilane. The carbonate diester produced by the production method according to this embodiment is not particularly limited and may be determined depending on the intended use of the carbonate diester. Examples of intended uses of the carbonate diester include solvents for electrolytic solutions and the like, alkylating agents, carbonylating agents, gasoline additives, diesel fuel additives, and raw materials for polymers such as polyurethane and polycarbonate.

[0060] In the reaction step of this embodiment, it is preferable to use a compound represented by general formula (1) as the carbonate monoester salt, and it is preferable to use a compound represented by general formula (2) as the alkoxysilane. Therefore, in the production method according to this embodiment, a carbonate diester represented by general formula (3) is suitably produced, as shown in the following reaction formula:

[0061]

[0062] In the general formulas (1) to (3), R １ , R ２ , A ｍ＋ , m, and p are as already explained. １ may be the same group or different groups, but are preferably the same group.

[0063] Specific examples of the carbonate diester represented by general formula (3) include dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, di-n-butyl carbonate, ethyl methyl carbonate, ethyl isopropyl carbonate, dicyclohexyl carbonate, divinyl carbonate, diallyl carbonate, methyl propargyl carbonate, and diphenyl carbonate.

[0064] 1-6. Reaction Solvent In the reaction step, the reaction between the carbonate monoester salt and the alkoxysilane may be carried out in a solvent or without a solvent. From the viewpoint of achieving the production of the carbonate monoester salt under milder conditions, it is preferable to carry out the reaction under solvent-free conditions. In other words, carrying out the reaction under solvent-free conditions increases the contact opportunity between the carbonate monoester salt and the alkoxysilane, thereby improving the reaction rate and enabling a shorter reaction time, or enabling a catalytic reaction at a lower reaction temperature, which is preferable. Furthermore, when the solubility of the product carbonate diester in the reaction solution is low, it is also preferable to add a good solvent such as an aprotic polar solvent to the reaction system. This is because it is believed that adding a good solvent to the reaction solution makes it easier for the carbonate diester to dissolve in the reaction solution, allowing the reaction to proceed smoothly.

[0065] In the present disclosure, "solvent-free conditions" means that no reaction solvent other than the reaction reagent is used, and when a reaction substrate such as an alcohol is also used as a reaction solvent, the reaction substrate is not considered to be a reaction solvent and is considered to fall under solvent-free conditions. Furthermore, when the reaction step is carried out in a reaction solvent, the reaction solvent may be used alone or in any combination and ratio of two or more types.

[0066] The reaction solvent is not particularly limited as long as it does not impair the effects of the present disclosure, and examples thereof include aliphatic hydrocarbons such as butane, hexane, octane, and cyclohexane; aromatic hydrocarbons such as benzene, toluene, and xylene; heterocyclic aromatic compounds such as pyridine; aprotic polar solvents such as N,N-dimethylformamide, dimethylacetamide, dimethyl sulfoxide, 1,3-dimethyl-2-imidazolidinone, and N-methylpyrrolidone (NMP); ethers such as diethyl ether, diisopropyl ether, 1,2-dimethoxyethane, tetrahydrofuran, and dioxane; nitriles such as acetonitrile, propionitrile, butyronitrile, benzonitrile, and 2-cyanopyridine; and ketones such as acetone, isopropyl methyl ketone, and methyl isobutyl ketone. Among these, the reaction solvent is preferably an aprotic polar solvent, and N-methylpyrrolidone (NMP) is more preferred, due to its high solubility of the carbonate diester.

[0067] When the reaction step is carried out in the presence of a reaction solvent, the amount of reaction solvent used (charge amount; total amount when multiple types are used) is not particularly limited as long as it is within a range that does not impair the effects of the present disclosure. Specifically, the reaction solvent is usually 0.5 mL or more, preferably 1.0 mL or more, more preferably 2.0 mL or more, per 1.0 mmol of carbonate monoester salt, and usually 10.0 mL or less, preferably 5.0 mL or less. That is, suitable ranges for the amount of reaction solvent used include, for example, 0.5 mL to 10.0 mL, 1.0 mL to 10.0 mL, and 2.0 mL to 5.0 mL per 1.0 mmol of carbonate monoester salt. By using the reaction solvent in the above range, contact between the carbonate monoester salt and the alkoxysilane can be ensured. Furthermore, if the reaction solvent is a good solvent for the reaction substrates and products, the solubility of the reaction substrates and products can be improved, allowing the reaction to proceed smoothly.

[0068] 1-7. Reaction Temperature The reaction temperature in the reaction step is not particularly limited and may be appropriately adjusted depending on the type of reaction substrate, the type of catalyst, the presence or absence of a solvent, and the like. Specifically, the reaction temperature is usually 80°C or higher, preferably 100°C or higher, more preferably 120°C or higher, and even more preferably 130°C or higher, and usually 250°C or lower, preferably 200°C or lower, more preferably 160°C or lower, and even more preferably 150°C or lower. That is, suitable ranges of the reaction temperature include 80°C or higher and 250°C or lower, 100°C or higher and 200°C or lower, 120°C or higher and 160°C or lower, and 130°C or higher and 150°C or lower. According to the production method of this embodiment, a high reaction rate can be achieved by selecting an appropriate catalyst, making it possible to produce a carbonate diester under milder temperature conditions.

[0069] 1-8. Reaction Time The reaction time in the reaction step is not particularly limited and may be adjusted appropriately depending on the reaction temperature, catalyst amount, reaction scale, and the like. Specifically, the reaction time is usually 1 hour or more, preferably 3 hours or more, more preferably 5 hours or more, and even more preferably 10 hours or more, and usually 120 hours or less, preferably 100 hours or less, more preferably 80 hours or less, and even more preferably 60 hours or less. That is, suitable ranges of the reaction time include 1 hour or more and 120 hours or less, 3 hours or more and 100 hours or less, 5 hours or more and 80 hours or less, and 10 hours or more and 60 hours or less. As described above, according to the production method of this embodiment, a high reaction rate can be achieved by selecting an appropriate catalyst, and therefore, a carbonate diester can be produced in a relatively short reaction time.

[0070] 1-9. Operation Procedure The reaction step can be carried out, for example, as follows. First, a carbonate monoester salt, an alkoxysilane, a catalyst, and, if necessary, a reaction solvent are supplied to a reactor. This operation may be carried out under an air atmosphere or an inert gas atmosphere such as nitrogen or argon. The reactor is not particularly limited as long as it is made of a material that is stable against the reaction reagents and the carbonate diester. When the production method according to this embodiment includes a carbonate monoester salt production step described below, the reactor used in the carbonate monoester salt production step may be used directly in the reaction step. Next, the reaction solution is heated to react the carbonate monoester salt with the alkoxysilane. It is preferable to stir the reaction solution during the reaction. The method for stirring the reaction solution is not particularly limited, and for example, a method of stirring the reaction solution using a stirring means such as a magnetic stirrer or stirring blade can be used. In addition to stirring, a flow-type reactor can be used in which the reaction solution is continuously supplied to a reaction tube equipped with a catalyst and heated.

[0071] Alternatively, when the production method according to this embodiment includes the carbonate monoester salt production step described below, the reaction step may be carried out as follows. First, an alcohol, a base, an alkoxysilane, and a catalyst are added to a reactor. Next, a carbon dioxide-containing gas is supplied into the reactor, and the alcohol, the base, and the carbon dioxide are reacted to produce a carbonate monoester salt. Subsequently, the reaction step is carried out in this reactor without purifying the carbonate monoester salt. That is, the reaction solution is heated in this reactor, and the carbonate monoester salt is reacted with the alkoxysilane to produce a carbonate diester.

[0072] The alcohol and base used in the carbonate monoester salt production step do not inhibit the reaction in the reaction step, so the reaction step can be carried out in the presence of either or both of an alcohol and a base. Furthermore, the alkoxysilane and catalyst used in the reaction step do not inhibit the carbonate monoester salt production step, so the carbonate monoester salt production step can be carried out in the presence of either or both of an alkoxysilane and a catalyst. Furthermore, the reaction in the carbonate monoester salt production step proceeds at a lower temperature than the reaction in the reaction step. Therefore, as described above, by having the alkoxysilane and catalyst present in the reaction system from the beginning of the reaction when producing a carbonate monoester salt, the carbonate monoester salt production step and the reaction step can be carried out continuously without adding the alkoxysilane and catalyst to the reactor after the carbonate monoester salt production step.

[0073] 2. Carbonate Monoester Salt Production Step In this embodiment, the carbonate monoester salt may be a commercially available product or may be synthesized, but it is preferable to synthesize and use the carbonate monoester salt. When synthesizing the carbonate monoester salt, specifically, a carbonate monoester salt production step may be carried out before the reaction step, in which an alcohol, a base, and a carbon dioxide-containing gas are brought into contact with each other. At this time, the total pressure P ｔ The partial pressure P of carbon dioxide gas in the carbon dioxide-containing gas ＣＯ２ It is preferable to set the ratio to be 0.0001 or more and 1.00 or less.

[0074] 2-1. Alcohol The alcohol is an alcohol having a hydrocarbon group from which the carbonate monoester salt is derived, and is selected depending on the carbonate monoester salt to be synthesized. When the carbonate monoester salt synthesized in the carbonate monoester salt production step is a compound represented by general formula (1), the alcohol is a compound represented by the following general formula (1'). In general formula (1'), R １ represents R in general formula (1). １ The same applies to the preferred embodiments. １ OH (1')

[0075] The alcohol includes aliphatic alcohols and aromatic alcohols. Specific examples of the aliphatic alcohol include methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, isobutyl alcohol, n-pentyl alcohol, isopentyl alcohol, neopentyl alcohol, n-hexyl alcohol, n-heptyl alcohol, n-octyl alcohol, n-nonyl alcohol, n-decyl alcohol, n-undecyl alcohol, n-dodecyl alcohol, n-tridecyl alcohol, n-tetradecyl alcohol, n-pentadecyl alcohol, n-hexadecyl alcohol, and n-heptadecyl alcohol. alkyl alcohols such as cyclopropanol, n-octadecyl alcohol, n-nonadecyl alcohol, and n-docosyl alcohol; cycloalkanols such as cyclopropanol, cyclobutanol, cyclopentanol, and cyclohexanol; alkenyl alcohols such as vinyl alcohol, allyl alcohol, 1-propen-1-ol, isopropenyl alcohol, 1-buten-1-ol, 2-buten-1-ol, 2-methylallyl alcohol, 1-hexen-1-ol, 1-hepten-1-ol, 1-octen-1-ol, and 2-methyl-1-propen-1-ol; and alkynyl alcohols such as propargyl alcohol.

[0076] Specific examples of aromatic alcohols include phenol, 1-naphthalene, 2-naphthalene, 1-hydroxyphenanthrene, 2-hydroxyphenanthrene, 3-hydroxyphenanthrene, 4-hydroxyphenanthrene, 9-hydroxyphenanthrene, 1-hydroxyanthracene, 2-hydroxyanthracene, 9-hydroxyanthracene, 1-hydroxypyrene, 2-hydroxypyrene, 4-hydroxypyrene, 1-hydroxytriphenylene, 2-hydroxytriphenylene, 2-hydroxypyridine, 3-hydroxypyridine, and 4-hydroxypyridine.

[0077] From the viewpoint of improving the reaction rate, the lower limit of the amount of alcohol used (charge amount) is preferably m × 1.0 equivalent or more (m has the same meaning as m in general formula (1)), more preferably m × 1.3 equivalent or more, and even more preferably m × 1.5 equivalent or more, relative to 1.0 equivalent of the amount of base used (charge amount). The upper limit of the amount of alcohol used (charge amount) is preferably m × 5.0 equivalent or less. That is, suitable ranges of the amount of alcohol used (charge amount) include, for example, m × 1.0 equivalent or more and m × 5.0 equivalent or less, m × 1.3 equivalent or more and m × 5.0 equivalent or less, and m × 1.5 equivalent or more and m × 5.0 equivalent or less, relative to 1.0 equivalent of the amount of base used (charge amount).

[0078] 2-2. Base The base is a base from which the cationic component forming the carbonate monoester salt is derived, and is selected depending on the carbonate monoester salt to be synthesized. When the carbonate monoester salt synthesized in the carbonate monoester salt production step is a compound represented by general formula (1), the base is selected from the group consisting of A ｍ＋ That is, A is a base from which one or more cations selected from the group consisting of ammonium cation, amidinium cation, guanidinium cation, phosphonium cation, phosphazenium cation, carbocation, Group 1 metal cation, and Group 2 metal cation are derived.

[0079] Examples of bases from which ammonium cations are derived include primary amines such as methylamine, ethylamine, isopropylamine, n-butylamine, and 2-hydroxyethylamine; secondary amines such as dimethylamine, diethylamine, and dicyclohexylamine; tertiary amines such as trimethylamine and triethylamine; and quaternary ammonium hydroxides such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, phenyltrimethylammonium hydroxide, benzyltrimethylammonium hydroxide, and tetrabutylammonium fluoride.

[0080] Examples of bases from which the amidinium cation is derived include formamidine, acetamidine, 1,5-diazabicyclo[4.3.0]non-5-ene, 1,8-diazabicyclo[5.4.0]undec-7-ene, and derivatives thereof into which a substituent has been introduced. Examples of the substituent include R １ Examples of the substituent that the hydrocarbon group represented by the following formula may have include those described above.

[0081] Examples of bases from which guanidinium cations are derived include 1,1,3,3-tetramethylguanidine, 2-tert-butyl-1,1,3,3-tetramethylguanidine, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, and derivatives thereof into which a substituent has been introduced. Examples of the substituent include R １ Examples of the substituent that the hydrocarbon group represented by the following formula may have include those described above.

[0082] Bases from which phosphonium cations are derived include tertiary phosphines such as triphenylphosphine and tri-tert-butylphosphine; and quaternary phosphonium cations such as tetraphenylphosphine, tetra-p-tolylphosphine, triphenylbenzylphosphine, triphenylbutylphosphine, tetraethylphosphine, and tetrabutylphosphine.

[0083] Examples of bases from which phosphazenium cations are derived include tert-butylimino-tris(dimethylamino)phosphorane, tert-butylimino-tri(pyrrolidino)phosphorane, 2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorine, and 1-tert-butyl-2,2,4,4,4-pentakis(dimethylamino)-2λ. ５ , 4λ ５ - Catenadi(phosphazene), 1-tert-butyl-4,4,4-tris(dimethylamino)-2,2-bis[tris(dimethylamino)phosphoranylideneamino]-2λ ５ , 4λ ５-catenadi(phosphazene), and derivatives thereof into which a substituent has been introduced. Examples of the substituent include R １ Examples of the substituent that the hydrocarbon group represented by the following formula may have include those described above.

[0084] Bases from which carbocations are derived include triphenylmethyl chloride, triphenylmethanol, 1,3,5-cycloheptatriene, and azulene.

[0085] Salts from which Group 1 metal cations are derived include Group 1 metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide; Group 1 metal bicarbonates such as lithium bicarbonate, sodium bicarbonate, and potassium bicarbonate; Group 1 metal carbonates such as lithium carbonate, sodium carbonate, and potassium carbonate; and Group 1 metal alkoxides such as lithium methoxide, sodium methoxide, potassium methoxide, lithium ethoxide, sodium ethoxide, and potassium ethoxide.

[0086] Salts from which Group 2 metal cations are derived include Group 2 metal hydroxides such as magnesium hydroxide and calcium hydroxide.

[0087] 2-3. Carbon Dioxide-Containing Gas In the carbonate monoester salt production process, a carbon dioxide-containing gas containing carbon dioxide (gas) as a raw material is used. The carbon dioxide may be prepared as an industrial gas, or may be separated and recovered from exhaust gases from factories, power plants, etc. Carbon dioxide may be used alone or in the form of a mixed gas in combination with a gas other than carbon dioxide as long as the effects of the present disclosure are not significantly impaired. However, from the viewpoint of improving reactivity, it is preferable to use carbon dioxide alone. Examples of the gas other than carbon dioxide include inert gases such as nitrogen and argon.

[0088] The method for introducing a carbon dioxide-containing gas into the reaction system is not particularly limited, and may be a method of replacing the atmosphere in the reactor with carbon dioxide, or a method of supplying carbon dioxide into the reaction solution by bubbling. Of these, the method of supplying by bubbling is preferred because it can increase the opportunity for the alcohol and base to come into contact with carbon dioxide and improve the reaction efficiency.

[0089] Total pressure P of carbon dioxide-containing gas ｔ is not particularly limited, but from the viewpoint of reaction efficiency, it is preferably 0.01 MPa or more, more preferably 0.05 MPa or more, even more preferably 0.08 MPa or more, and is preferably 5.0 MPa or less, more preferably 3.0 MPa or less, even more preferably 1.0 MPa or less, particularly preferably 0.50 MPa or less, and most preferably 0.20 MPa or less. That is, the total pressure P of the carbon dioxide-containing gas ｔ Suitable ranges of the total pressure P of the carbon dioxide-containing gas include, for example, 0.01 MPa or more and 5.0 MPa or less, 0.01 MPa or more and 3.0 MPa or less, 0.05 MPa or more and 1.0 MPa or less, 0.05 MPa or more and 0.50 MPa or less, and 0.08 MPa or more and 0.20 MPa or less. When carbon dioxide is introduced into the reaction system by bubbling, the total pressure P of the carbon dioxide-containing gas is ｔ From the viewpoint of work efficiency, it is preferable that the pressure is approximately the same as atmospheric pressure, that is, (0.1±0.05) MPa.

[0090] Partial pressure P of carbon dioxide gas in carbon dioxide-containing gas ＣＯ２ is not particularly limited, but from the viewpoint of reaction efficiency, it is preferably 0.005 MPa or more, more preferably 0.01 MPa or more, even more preferably 0.05 MPa or more, particularly preferably 0.10 MPa or more, and is preferably 5.0 MPa or less, more preferably 3.0 MPa or less, even more preferably 1.0 MPa or less, particularly preferably 0.50 MPa or less, and most preferably 0.20 MPa or less. That is, the partial pressure P of carbon dioxide gas in the carbon dioxide-containing gas ＣＯ２Suitable ranges for the pressure include, for example, 0.005 MPa or more and 5.0 MPa or less, 0.01 MPa or more and 3.0 MPa or less, 0.05 MPa or more and 1.0 MPa or less, 0.10 MPa or more and 0.50 MPa or less, and 0.005 MPa or more and 0.20 MPa or less.

[0091] In the carbonate monoester salt production process, the total pressure P of the carbon dioxide-containing gas ｔ The partial pressure P of carbon dioxide gas in the carbon dioxide-containing gas ＣＯ２ The ratio (P ＣＯ２ / P ｔ ) is not particularly limited, but is preferably 0.05 or more, more preferably 0.10 or more, even more preferably 0.50 or more, and is usually 1.00 or less, preferably 0.80 or less, more preferably 0.60 or less, even more preferably 0.50 or less, and particularly preferably 0.30 or less. ＣＯ２ / P ｔ Suitable ranges for are, for example, 0.05 or more and 1.00 or less, 0.10 or more and 0.80 or less, 0.50 or more and 0.60 or less, 0.05 or more and 0.50 or less, and 0.05 or more and 0.30 or less.

[0092] The above pressure means absolute pressure. ｔ " and "The partial pressure P of carbon dioxide gas in the carbon dioxide-containing gas ＣＯ２ " means the pressure (25°C) immediately after introducing the carbon dioxide-containing gas into the reactor, that is, at the start of the reaction.

[0093] In the carbonate monoester salt production step, the reaction of the alcohol, the base, and carbon dioxide may be carried out in a solvent or without a solvent. From the viewpoint of achieving production of the carbonate monoester salt under milder conditions, for example, from the viewpoint of increasing the reaction rate and shortening the reaction time, it is preferable to carry out the reaction without a solvent.

[0094] The type of reaction solvent can be appropriately selected from nonpolar solvents, protic polar solvents, and aprotic polar solvents, and is preferably at least one selected from the group consisting of protic polar solvents and aprotic polar solvents. The reaction solvent may be used alone or in any combination and ratio of two or more.

[0095] Examples of non-polar solvents include aliphatic hydrocarbons such as butane, hexane, octane, and cyclohexane; aromatic hydrocarbons such as benzene, toluene, and xylene; and ethers such as 1,4-dioxane and diethyl ether.

[0096] Protic polar solvents include, for example, carboxylic acids such as formic acid and acetic acid.

[0097] Examples of aprotic polar solvents include tertiary carboxylic acid amides, sulfoxides such as dimethyl sulfoxide, ketones such as acetone and isopropyl ketone, lactones such as γ-butyrolactone, lactams such as N-methylpyrrolidone (NMP), nitriles such as acetonitrile, propionitrile, butyronitrile, benzonitrile, and 2-cyanopyridine, urea derivatives, sulfones, carboxylic acid esters such as ethyl acetate, and carbonate esters. Of these, the aprotic polar solvent is preferably N-methylpyrrolidone from the viewpoints of improving the reaction rate, ease of availability, and cost.

[0098] The amount of the reaction solvent used is not particularly limited, but is usually 0.5 times or more, preferably 1.0 times or more, more preferably 1.5 times or more, relative to the volume of the base, and is usually 20 times or less, preferably 15 times or less, more preferably 10 times or less.

[0099] The reaction temperature in the carbonate monoester salt production step is not particularly limited and is usually from 1° C. to 50° C., and from the viewpoint of economy, it is preferably room temperature (rt). In the present disclosure, room temperature refers to a temperature range from 15° C. to 30° C.

[0100] 2-6. Reaction Time The reaction time between the alcohol, base, and carbon dioxide is not particularly limited and may be adjusted appropriately depending on the reaction temperature, reaction scale, and the like. Specifically, the reaction time is preferably 5 minutes or more, more preferably 10 minutes or more, and even more preferably 20 minutes or more, and is usually 48 hours or less, preferably 24 hours or less, more preferably 20 hours or less, and even more preferably 3 hours or less. That is, suitable ranges for the reaction time include 5 minutes to 48 hours, 5 minutes to 24 hours, 10 minutes to 20 hours, and 20 minutes to 3 hours. In the carbonate monoester salt production process, the "reaction time" refers to the time during which the carbon dioxide-containing gas is continuously supplied into the reactor.

[0101] 2-7. Reactor The reaction apparatus used in the carbonate monoester salt production process is not particularly limited as long as it is made of a material stable to the reaction reagents and the carbonate monoester salt, and may be selected depending on the method for introducing the carbon dioxide-containing gas into the reaction system. When the carbon dioxide-containing gas is introduced into the reaction system by replacing the atmosphere inside the reactor, the reactor is preferably a sealed reactor (sealed reactor), more preferably a sealed pressure-resistant reactor, and even more preferably a stainless steel autoclave. Furthermore, the reactor preferably has a volume 10 to 100 times the volume of the mixture containing the alcohol, base, and, if necessary, the reaction solvent. When carbon dioxide is introduced into the reaction system by bubbling, the reactor preferably has a supply pipe for supplying carbon dioxide to the reaction system by bubbling and an exhaust pipe for discharging the gas inside the reactor. Furthermore, the reactor preferably has a volume 1.5 to 100 times the volume of the mixture containing the alcohol, base, and, if necessary, the reaction solvent. The reactor may be equipped with a magnetic stirrer or stirring blades for stirring the reaction solution.

[0102] 2-8. Operating Procedure The carbonate monoester salt production process can be carried out, for example, as follows. First, the raw material alcohol and base are added to a reactor. At this time, it is preferable to replace the reactor with an inert gas atmosphere such as nitrogen or argon. Also, at this time, as described above in "1-8. Operating Procedure," an alkoxysilane and a catalyst to be used in the reaction process may be added to the reactor. Next, a carbon dioxide-containing gas is supplied into the reactor to react the alcohol, base, and carbon dioxide. When a solvent is used, the solvent may be added to the reactor, for example, simultaneously with the alcohol, before introducing the carbon dioxide into the reactor. Also, during the reaction, it is preferable to stir the reaction solution using a magnetic stirrer, stirring blades, or the like. After the reaction, the reaction solution is cooled, the remaining gas is discharged, and the reaction product is recovered.

[0103] 2-9. Other After the carbonate monoester salt production step, the obtained carbonate monoester salt can be purified by a purification method commonly used in the field of organic synthesis, such as filtration, adsorption, column chromatography, or distillation, before being subjected to the reaction step. Alternatively, the reaction mixture containing the carbonate monoester salt obtained in the carbonate monoester salt production step may be subjected to the reaction step without purification. The alcohol and base used in the carbonate monoester salt production step do not inhibit the reaction in the reaction step, so using a reaction mixture containing residual compounds in the reaction step does not adversely affect the progress of the reaction. Therefore, from an economical standpoint, it is preferable to subject the reaction mixture obtained in the carbonate monoester salt production step to the reaction step as is.

[0104] 3. Other Steps The production method according to this embodiment may include any other steps in addition to the reaction step. An example of such an optional step is a purification step for increasing the purity of the carbonate ester. Purification methods for the carbonate diester in the purification step can be those commonly used in the field of organic synthesis, such as filtration, adsorption, column chromatography, and distillation. Specifically, examples of such methods include filtering the obtained solid under a nitrogen atmosphere, washing with diethyl ether or the like, and vacuum drying.

[0105] The present disclosure will be described in more detail below with reference to examples, but modifications can be made as appropriate without departing from the spirit of the present disclosure. Therefore, the scope of the present disclosure should not be construed as being limited by the specific examples shown below.

[0106] <GC Measurement> Measurement of the product yield by gas chromatography (GC) was carried out under the following conditions: Apparatus name: GC-2014 (Shimadzu Corporation) Detector: FID (Flame Ionization Detector) Column: TC-1 (GL Sciences Inc.) Carrier gas: N ２ Internal standard substance: mesitylene Data processing: Lab solutions (Shimadzu Corporation)

[0107] Examples 1-1 to 1-3

[0108] A mixture containing a carbonate monoester salt was prepared by bubbling carbon dioxide gas through a mixture of ethanol (0.58 mL, 10.0 mmol) and 1,8-diazabicyclo[5.4.0]undec-7-ene (1.52 g, 10.0 mmol) at room temperature for 20 minutes at a flow rate of 0.1 L / min. This mixture, tetraethoxysilane (3.35 mL, 15.0 mmol), and cerium(IV) oxide (172 mg, 1.0 mmol) were placed in a sealed reactor and reacted for 3 hours at the reaction temperature shown in Table 1 to obtain diethyl carbonate. The yield of diethyl carbonate was calculated by GC measurement using mesitylene as an internal standard. The results are shown in Table 1.

[0109]

[0110] Table 1 shows that the reaction between the carbonate monoester salt and the alkoxysilane proceeds to produce a carbonate diester even at a low temperature of 100° C. Table 1 also shows that changing the reaction temperature from 100° C. to 125° C. increases the yield of the carbonate diester by 10 times, and changing the temperature to 150° C. further increases the yield of the carbonate diester.

[0111] Examples 2-1 to 2-4 and Comparative Examples 2-1 to 2-7

[0112] Carbon dioxide gas was passed through a mixture of ethanol (0.58 mL, 10.0 mmol), 1,8-diazabicyclo[5.4.0]undec-7-ene (1.52 g, 10.0 mmol), tetraethoxysilane (3.35 mL, 15.0 mmol), and the catalyst (172 mg) shown in Table 2 at room temperature for 10 minutes at a flow rate of 0.1 L / min. The resulting mixture was then heated at 120°C for 5 hours to obtain diethyl carbonate. The yield of the resulting diethyl carbonate was calculated by GC measurement using mesitylene as an internal standard. The results are shown in Table 2. The catalyst used in the reaction had been previously calcined at 600°C for 3 hours in an air atmosphere.

[0113]

[0114] Table 2 shows that the reaction between a carbonate monoester salt and an alkoxysilane proceeds in the presence of a catalyst such as cerium (IV) oxide, dibutyltin dilaurate, or dibutyltin oxide. That is, the above examples confirm that cerium catalysts and tin catalysts exhibit catalytic activity in the reaction of a carbonate monoester salt with an alkoxysilane to produce a carbonate diester. Table 2 also shows that cerium oxide exhibits particularly high catalytic activity in the reaction between a carbonate monoester salt and an alkoxysilane.

[0115] Examples 3-1 and 3-2

[0116] A mixture containing a carbonate monoester salt was prepared by passing a carbon dioxide-containing gas shown in Table 3 through a mixture of ethanol (0.58 mL, 10.0 mmol) and 1,8-diazabicyclo[5.4.0]undec-7-ene (1.52 g, 10.0 mmol) at a flow rate of 0.1 L / min for 20 minutes at room temperature. This mixture, tetraethoxysilane (3.35 mL, 15.0 mmol), and cerium(IV) oxide (172 mg, 1.0 mmol) were placed in a sealed reactor and reacted at 150°C for 5 hours to obtain diethyl carbonate. The yield of the resulting diethyl carbonate was calculated by GC measurement using mesitylene as an internal standard. The results are shown in Table 3.

[0117] Example 3-3

[0118] Ethanol (0.58 mL, 10.0 mmol) and 1,8-diazabicyclo[5.4.0]undec-7-ene (1.52 g, 10.0 mmol) were placed in a sealed reactor, and carbon dioxide gas was pressurized and charged to the reactor to a carbon dioxide pressure of 3.0 MPa. The reaction was allowed to proceed at room temperature for 20 minutes to prepare a mixture containing a carbonate monoester salt. Tetraethoxysilane (3.35 mL, 15.0 mmol) and cerium(IV) oxide (172 mg, 1.0 mmol) were added to the mixture, and the reaction was allowed to proceed at 150°C for 5 hours to obtain diethyl carbonate. The yield of diethyl carbonate was calculated by GC measurement using mesitylene as an internal standard. The results are shown in Table 3.

[0119]

[0120] From Table 3, in the reaction of an alcohol, a base, and a carbon dioxide-containing gas, when a carbon dioxide-containing gas is aerated (P ｔ = 0.1 MPa), the yield of the carbonate diester was hardly affected by the partial pressure of carbon dioxide gas in the carbon dioxide-containing gas, and therefore it is presumed that if the carbon dioxide-containing gas is passed through for a sufficient time to form a sufficient amount of carbonate monoester salt, the carbonate diester can be obtained in high yield. Furthermore, Table 3 shows that in the reaction of an alcohol, a base, and a carbon dioxide-containing gas, when the partial pressure of carbon dioxide gas in the carbon dioxide-containing gas is 1.0, increasing the total pressure of the carbon dioxide-containing gas from 0.1 MPa to 3.0 MPa increased the yield of the carbonate diester. This is presumably because, under high-pressure conditions, in addition to an increase in the amount of carbonate monoester salt produced, the amount of carbon dioxide in the reactor increases due to the dissolution of carbon dioxide in the reaction liquid, and the reaction equilibrium shifts toward the product system, thereby increasing the yield of the carbonate diester.

[0121] Examples 4-1 to 4-3

[0122] A mixture containing a carbonate monoester salt was prepared by bubbling a carbon dioxide-containing gas through a mixture of ethanol (0.58 mL, 10.0 mmol) and 1,8-diazabicyclo[5.4.0]undec-7-ene (1.52 g, 10.0 mmol) at room temperature for 20 minutes at a flow rate of 0.1 L / min. This mixture, tetraethoxysilane (3.35 mL, 15.0 mmol), and cerium(IV) oxide (682 mg, 4.0 mmol) were placed in a sealed reactor and reacted at 100°C for the time shown in Table 4 to obtain diethyl carbonate. The yield of diethyl carbonate was calculated by GC measurement using mesitylene as an internal standard. The results are shown in Table 4.

[0123]

[0124] From Table 4, in the reaction of an alcohol, a base, and a carbon dioxide-containing gas, when a carbon dioxide-containing gas is aerated (P ｔ = 0.1 MPa), the higher the partial pressure of carbon dioxide gas in the carbon dioxide-containing gas and the longer the reaction time, the higher the yield of the carbonate monoester salt produced, and as a result, the higher the yield of the carbonate diester obtained. Furthermore, a comparison of Tables 1 and 4 shows that in the reaction of a carbonate monoester salt with an alkoxysilane, the yield of the carbonate ester can be improved by increasing the amount of catalyst or extending the reaction time, even under low-temperature conditions such as 100°C.

[0125] Examples 5-1 to 5-8

[0126] A mixture containing a carbonate monoester salt was prepared by bubbling carbon dioxide gas through a mixture of ethanol (0.44 mL, 7.5 mmol) and base (7.5 mmol) at a flow rate of 0.1 L / min at room temperature for 10 minutes. This mixture, tetraethoxysilane (3.35 mL, 15.0 mmol), and cerium(IV) oxide (172 mg, 1.0 mmol) were placed in a sealed reactor and reacted at 150°C to obtain diethyl carbonate. The yield of diethyl carbonate was calculated by GC measurement using mesitylene as an internal standard. The results are shown in Table 5.

[0127]

[0128] Table 5 shows that when a carbonate diester is produced by reacting a carbonate monoester salt with an alkoxysilane, salts of a carbonate monoester with various cation species can be used as the carbonate monoester salt. Furthermore, it can be seen that, among the carbonate monoester salts, carbonate monoester amidinium salts and carbonate monoester guanidinium salts are particularly useful as the carbonate monoester salts, and that carbonate diesters can be obtained efficiently.

[0129] Example 6-1

[0130] Methanol (0.30 mL, 7.5 mmol) and 1,8-diazabicyclo[5.4.0]undec-7-ene (1.14 g, 7.5 mmol) were placed in a sealed reactor, and carbon dioxide gas was pressurized and charged to the reactor to a carbon dioxide pressure of 0.4 MPa. The reaction was allowed to proceed at room temperature for 20 minutes to prepare a mixture containing a carbonate monoester salt. Tetramethoxysilane (2.22 mL, 15.0 mmol) and cerium(IV) oxide (172 mg, 1.0 mmol) were added to the mixture, and the reaction was allowed to proceed at 150°C for 48 hours to obtain dimethyl carbonate. The yield of the resulting dimethyl carbonate was calculated by GC measurement using mesitylene as an internal standard. The results are shown in Table 6.

[0131] Example 6-2

[0132] A mixture containing a carbonate monoester salt was prepared by bubbling carbon dioxide gas through a mixture of 1-butanol (0.66 mL, 7.5 mmol) and 1,8-diazabicyclo[5.4.0]undec-7-ene (1.14 g, 7.5 mmol) at room temperature for 10 minutes at a flow rate of 0.1 L / min. This mixture, tetrabutoxysilane (5.35 mL, 15.0 mmol), and cerium(IV) oxide (172 mg, 1.0 mmol) were placed in a sealed reactor and reacted at 150°C for 48 hours to obtain dibutyl carbonate. The yield of dibutyl carbonate was calculated by GC measurement using mesitylene as an internal standard. The results are shown in Table 6.

[0133]

[0134] According to the present invention, a carbonate diester can be produced without using a sacrificial reagent such as an alkyl halide or phosgene by reacting a carbonate monoester salt with an alkoxysilane in the presence of one or more catalysts selected from the group consisting of cerium catalysts and tin catalysts.

Claims

1. A method for producing a carbonate diester, comprising a reaction step of reacting a carbonate monoester salt with an alkoxysilane in the presence of one or more catalysts selected from the group consisting of cerium catalysts and tin catalysts.

2. 2. The method for producing a carbonate diester according to claim 1, wherein the carbonate monoester salt is a compound represented by general formula (1), the alkoxysilane is a compound represented by general formula (2), and the carbonate diester is a compound represented by general formula (3). 【Chemistry 1】 (In the general formula, R １ are each independently a substituted or unsubstituted hydrocarbon group; R ２ are each independently a substituted or unsubstituted hydrocarbon group; A ｍ＋ is an m-valent cation derived from a base represented by A; m is 1 or 2; p is an integer of 1 to 4; when p is 1 or 2, there are a plurality of R ２ may be linked to each other to form a ring.)

3. R １ The method for producing a carbonic acid diester according to claim 2, wherein is a substituted or unsubstituted aliphatic hydrocarbon group.

4. The method for producing a carbonic acid diester according to claim 2 or 3, wherein p is 2 or more and 4 or less.

5. The method for producing a carbonate diester according to any one of claims 1 to 3, wherein the reaction step is carried out at a temperature of 80°C or higher and 250°C or lower.

6. The method for producing a carbonate diester according to any one of claims 1 to 3, wherein the catalyst is at least one selected from the group consisting of cerium (IV) oxide, dialkyltin dialiphatic monocarboxylic acids, and dialkyltin oxides.

7. a carbonic acid monoester salt production step of contacting an alcohol, a base, and a carbon dioxide-containing gas before the reaction step, The total pressure P ｔ The partial pressure P of the carbon dioxide gas in the carbon dioxide-containing gas ＣＯ２ The method for producing a carbonate diester according to any one of claims 1 to 3, wherein the ratio of

8. The partial pressure P of the carbon dioxide gas in the carbon dioxide-containing gas ＣＯ２ The method for producing a carbonate diester according to claim 7, wherein the pressure is less than 0.100 MPa.

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