JP2013018744A - Method for producing vinylether - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing vinylether which gives high conversion rate of ether exchange reaction, excels in recyclability of raw material components and enables mass production at low cost industrially.SOLUTION: This method comprises: performing an ether exchange reaction between vinylethers and alcohols in the presence of a transition metal catalyst; and during the reaction or after completion of the reaction, while bubbling oxygen in the reaction mixture, distilling low boiling point components out to concentrate the reaction mixture. The low boiling point components may be distilled at around 50-100°C. In this reaction, the vinylethers may be used at a rate of excess molar equivalent to the alcohols. The oxygen may be bubbled at a rate of 5-100 L/min to 1 mole of the transition metal catalyst. The transition metal catalyst may be a paradium complex and/or cobalt complex.

Description

  The present invention relates to a method for producing vinyl ether, which has a high conversion rate of ether exchange reaction, is excellent in recyclability of raw material components, and can be mass-produced industrially at low cost.

  Vinyl ethers are used as resin raw materials and intermediates for various compounds. Resin raw materials are suitably used as polymer modifiers for synthetic resins in various fields such as molding resins, coating resins, adhesives, and pressure-sensitive adhesives. It is important for the polymer modifier to be able to supply various compounds for use, required characteristics, demand, and the like. Therefore, it is industrially very important that vinyl ethers can be supplied as a desired compound by changing the type of substituent in the molecule.

  As a method for changing the type of substituent of vinyl ethers, for example, a method of ether-exchange of alkyl vinyl ethers and alcohols is industrially useful. Japanese Laid-Open Patent Publication No. 9-87224 (Patent Document 1) proposes a method for producing a vinyl ether by ether exchange in the presence of a complex of palladium and a nitrogen bidentate ligand. In the examples of this document, ethanol and methyl vinyl ether were exchanged with ether in the presence of diacetato (1,10-phenanthroline) palladium (II), and after completion of the reaction, the reaction solution was concentrated at a bath temperature of 40 ° C. under reduced pressure. It is dried and the palladium complex in the concentrated residue is reused.

  Japanese Patent Application Laid-Open No. 2001-114718 (Patent Document 2) discloses a method of producing vinyl ether by exchanging ether while distilling by-produced alcohol out of the reaction system. In the examples of this document, n-butyl vinyl ether and n-dodecanol were reacted at 40 ° C. in the presence of a palladium acetate-1,10-phenanthroline complex, and the reaction system was reduced to 90 mmHg and produced by the reaction. The n-butyl vinyl ether distilled with the n-butanol is recovered.

  However, in these methods, in order to promote the reaction, if the temperature is raised, the transition metal is discolored and deactivated. Therefore, it is difficult to concentrate and distill unless it is under reduced pressure, and it is usually difficult to distill off a compound having a high boiling point at a reachable degree of reduced pressure. Moreover, the distillation operation at 40 ° C. decreases the condensation efficiency and recovery rate of low-boiling components, making it impossible to carry out an ether exchange reaction industrially at low cost.

  In JP 2003-206251 (Patent Document 3), in order to improve the yield, in the presence of a catalyst, ether exchange is performed while adjusting the dissolved oxygen concentration in the reaction solution to 10 ppm or more to produce vinyl ether. A method is disclosed. In the example of this document, n-dodecyl alcohol and n-butyl vinyl ether were supplied in a 200 ml reaction vessel while supplying oxygen to the reaction solution at a rate of 10 ml / min in the presence of cobalt (III) acetylacetonate. Is reacted at 30 ° C. to obtain n-dodecyl vinyl ether. However, this document does not describe distilling off low-boiling components (by-product n-butanol) from the reaction solution. Furthermore, the reaction temperature is low and it is difficult to improve the reaction efficiency.

JP 09-87224 A (claims, examples) JP 2001-114718 A (Claims, Examples) JP 2003-206251 A (Claims, Examples)

  Accordingly, an object of the present invention is to provide a method for producing vinyl ether that can effectively prevent the deactivation of a transition metal catalyst during the reaction step and increase the reaction efficiency even when the reaction temperature is increased.

  Another object of the present invention is to provide a method for producing vinyl ether that can be reused without deactivating the transition metal catalyst.

  Still another object of the present invention is to provide a method for producing vinyl ether capable of improving the condensation rate and recovery rate of the distilled low boiling point component.

  As a result of diligent studies to achieve the above-mentioned problems, the present inventors have found that in the method for producing vinyl ether, after the reaction step or the completion of the reaction, the low boiling point component is distilled out of the system while bubbling oxygen into the reaction mixture. The inventors have found that catalyst deactivation can be effectively prevented, reaction efficiency can be improved, and that transition metal catalysts can be used repeatedly, thereby completing the present invention.

That is, in the method of the present invention, (1) vinyl ether and (2) alcohol are reacted in the presence of a transition metal catalyst, and (3) vinyl ether formed by ether exchange [(2) Having vinyl ether]. In this method, the reaction mixture is concentrated by distilling low-boiling components while bubbling oxygen into the reaction mixture during the reaction step or after completion of the reaction. The low boiling point component may be distilled at about 50 to 100 ° C. (for example, 60 to 80 ° C.). (1) The vinyl ether may be used at a ratio of (2) an excess molar equivalent (for example, 6 to 25 times molar equivalent) to the alcohol. Oxygen may be bubbled at a rate of 5 to 100 liters / minute (for example, 10 to 80 liters / minute) with respect to 1 mole of the transition metal catalyst. The transition metal catalyst may be a palladium complex and / or a cobalt complex (particularly a palladium complex). (1) The vinyl ether may be at least one selected from C _1-6 alkyl vinyl ether and C _2-6 alkenyl vinyl ether. (2) The alcohol may be at least one selected from a linear or branched C _4-20 alkanol and an alcohol represented by the following formula (2a).

(In the formula, ring Z is a C _4-10 aliphatic hydrocarbon ring or a 4- to 8-membered heterocyclic ring containing at least one hetero atom selected from a nitrogen atom, an oxygen atom and a sulfur atom as a constituent atom of the ring. X represents a C _1-4 alkylene group, m is an integer of 1 to 4, and p is 0 or 1.
The low boiling point component may contain (1) unreacted vinyl ether and (4) alcohol produced as a by-product in the reaction.

  In the present invention, (1) vinyl ether and (2) alcohol are reacted in the presence of a residue obtained by distilling a low-boiling component from the reaction mixture after completion of the reaction, and (3) vinyl ether produced by ether exchange is produced. Includes methods. In this method, an ether exchange reaction may be performed under the same conditions as in the above reaction. For example, the low boiling point component may be distilled from the reaction mixture while bubbling oxygen during the reaction step or after completion of the reaction, the low boiling point component may be distilled at a specific temperature, (1) vinyl ether into (2) alcohol You may use it in the ratio of an excess molar equivalent with respect. In the present invention, (1) a vinyl ether and (2) an alcohol are reacted in the presence of a transition metal catalyst, and a low boiling point component is distilled while bubbling oxygen to the produced reaction mixture. A method of concentrating the reaction mixture is also included.

  In the present specification, the “reaction mixture” means all components (or all liquid components) in the system after the reaction step or after completion of the reaction. In the present specification, the upper limit and the lower limit of the numerical range can be arbitrarily combined.

  In the present invention, since the low boiling point component in the reaction mixture is distilled while bubbling oxygen, it is possible to effectively prevent the transition metal catalyst from being deactivated even when the temperature is high. Therefore, the reaction efficiency can be improved during the reaction step, and the transition metal catalyst in the concentrated residue can be reused after completion of the reaction. Moreover, in this invention, when vinyl ether is used in the ratio of an excess molar equivalent with respect to alcohol, reaction efficiency can be made still higher. Furthermore, in the present invention, the distilled low boiling point component can be efficiently condensed and recovered, and the recovered low boiling point component can be reused.

  The method for producing vinyl ether of the present invention comprises (1) a reaction step in which ether is exchanged (or vinyl exchange) between vinyl ether and (2) alcohol in the presence of a transition metal catalyst, and a reaction mixture (reaction) after the reaction step or completion of the reaction. A concentration step (or distillation step) in which a low-boiling component is distilled (or distilled off) while bubbling oxygen into the system or liquid phase) to concentrate the reaction mixture. The above reaction can be represented by the following reaction formula.

[Wherein R ¹ represents a monovalent non-aromatic organic group, and in formula (1), the carbon atom of R ¹ is bonded to an oxy group (oxygen atom); R ² is different from R ¹ Represents a monovalent or polyvalent non-aromatic organic group, and in formula (2), the hydroxyl group is bonded to the carbon atom of R ² ; m is an integer of 1 or more; Or an integer greater than or equal to 1]
[Reaction process]
(1) Vinyl ether In formula (1), the monovalent non-aromatic organic group (aliphatic organic group) represented by R ¹ is usually a chain or cyclic aliphatic hydrocarbon group. Examples of chain hydrocarbon groups include alkyl groups [eg, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, s-butyl, t-butyl, pentyl, isopentyl, hexyl, heptyl, octyl, 2-ethylhexyl, nonyl. , Decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, etc. linear or branched C _1-30 alkyl group (for example, C _1-18 alkyl group etc.)], alkenyl group [Groups corresponding to the alkyl groups, for example, linear or branched C _2-30 alkenyl groups such as vinyl, allyl, isopropenyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl groups (for example, C _2-18 Alkenyl group etc.)] etc. .

Examples of the cyclic hydrocarbon group include a cycloalkyl group [e.g., a _C4-10 cycloalkyl group such as cyclopentyl and cyclohexyl groups (e.g., a _C4-8 cycloalkyl group)], a cycloalkenyl group [e.g., cyclopentenyl, A C _4-10 cycloalkenyl group such as a cyclohexenyl group (for example, a C _4-8 cycloalkenyl group) and the like.

  The chain or cyclic aliphatic hydrocarbon group is a substituent inert to the ether exchange reaction, such as a halogen atom, an alkoxy group, a carboxyl group, an acyl group, an alkoxycarbonyl group, an amino group, or an N-alkyl-substituted amino group. , An N-acyl-substituted amino group or the like may be substituted.

Examples of the vinyl ether include linear or branched C _{1 1} -methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, t-butyl vinyl ether, pentyl vinyl ether, hexyl vinyl ether, and the like. Examples thereof include ₁₂ alkyl vinyl ethers; C _2-6 alkenyl vinyl ethers such as allyl vinyl ether.

These vinyl ethers can be used alone or in combination of two or more. Among these vinyl ether, in view of reactivity and handling _{properties, C 1-6} alkyl vinyl _{ethers, C 2-6} alkenyl vinyl ether _[especially, such as _{C 2-6} alkyl vinyl ethers (e.g., n- propyl vinyl ether _{C 3- 4-} alkyl vinyl ether)] is preferred.

  The boiling point of vinyl ether can be selected from the range of about 5 to 200 ° C. at normal pressure, for example, 45 to 100 ° C., preferably 50 to 80 ° C., more preferably about 55 to 75 ° C. (for example, 60 to 70 ° C.). It may be.

(2) Alcohol In formula (2), the monovalent or polyvalent (divalent or higher) non-aromatic organic group represented by R ² is a monovalent or polyvalent chain organic group and monovalent or polyvalent. It can be classified as a valent cyclic organic group. Examples of the monovalent chain organic group include the same chain hydrocarbon group as R ¹ (for example, a linear or branched C _1-30 alkyl group which may have a substituent, a substituent. And a linear or branched C _2-30 alkenyl group which may be present).

The polyvalent chain organic group is usually a polyvalent chain hydrocarbon group or a heteroatom-containing group. Examples of the polyvalent chain hydrocarbon group include a divalent chain hydrocarbon group [for example, an alkylene group (for example, methylene, ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene). , Dodecylene, tridecylene, tetradecylene, pentadecylene, hexadecylene, heptadecylene, a linear or branched C _1-30 alkylene group such as an octadecylene group (for example, a C _1-18 alkylene group), an alkenylene group (to the alkylene group) Corresponding alkenylene group, for example, linear or branched C _2-30 alkenylene group (for example, C _2-18 alkenylene group) such as vinylene, arylene group, etc.]], trivalent chain hydrocarbon group [ For example, propane-triyl group, 1,1,1-trimethyl Linear or branched C _3-30 alkane-triyl group (eg, C _3-18 alkane-triyl group) such as rupropane-triyl group], tetravalent chain hydrocarbon group [eg, butane-tetrayl, etc. Group, a linear or branched C _4-30 alkane-tetrayl group such as 2,2-dimethylpropane-tetrayl group (for example, C _4-18 alkane-tetrayl group, etc.) and the like.

Examples of the polyvalent chain heteroatom-containing group, for example, a divalent chain heteroatom-containing group ^[e.g., -R 2a ^{-X-R 2b} - (In the ^{formula, R 2a} and ^{R 2b} are the same or different And an alkylene group, and X represents an oxygen atom, a sulfur atom, —CO—, —SO—, —SO ₂ —, or NH).

  The polyvalent chain organic group may be substituted with a substituent (such as a halogen atom or an alkoxy group) inactive to the ether exchange reaction exemplified above.

Examples of the monovalent or polyvalent cyclic organic group include a C _4-10 aliphatic hydrocarbon ring, or at least one hetero selected from a nitrogen atom (N), an oxygen atom (O), and a sulfur atom (S). Examples thereof include groups composed of 4- to 8-membered heterocycles containing atoms as constituent atoms of the ring (such as mono to tetrayl groups of these rings).

As alcohol, methanol, ethanol, n-propanol, isopropanol, n-butanol, t-butanol, pentanol, isopentyl alcohol, hexanol, heptanol, octanol, nonyl alcohol, decyl alcohol, lauryl alcohol, cetyl alcohol, stearyl alcohol, etc. A linear or branched C _1-20 alkanol of C _2-6 alkenyl alcohol such as allyl alcohol; ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1 C _2-10 alkanediols such as 1,3-butanediol, 1,4-butanediol; poly C _2-4 alkylene glycols such as diethylene glycol; glycerin, trimethylolpropane, penta Examples include alkanetri to tetraol such as erythritol; alcohol represented by the formula (2a) and the like.

In the formula (2a), examples of the aliphatic hydrocarbon ring represented by ring Z include a cycloalkane ring [for example, a C _4-10 cycloalkane ring such as cyclopentane, cyclohexane, cyclooctane ring (for example, C _{4 -8} cycloalkane ring)], cycloalkene ring [eg C _4-10 cycloalkene ring such as cyclopentene, cyclohexene ring, etc.], polycyclic saturated hydrocarbon ring [eg bornane, norbornane, adamantane, tricyclodecane Di- or tricycloalkane rings such as rings (eg di- or tri-C _7-10 cycloalkane rings), etc.], polycyclic unsaturated hydrocarbon rings [eg di- or tricycloalkene rings such as bornene, norbornene (eg , Di- or tri-C _7-10 cycloalkene ring) and the like.

  The heterocyclic ring represented by ring Z may be either a monocyclic heterocyclic ring or a condensed heterocyclic ring. Moreover, the heterocyclic ring should just be a 4-8 membered ring, Preferably it is a 4-7 membered ring (for example, 4-6 membered ring). Typical heterocycles include N-containing heterocycles (eg, azetidine, pyrrolidine, imidazolidine, piperidine, piperazine, etc.), O-containing heterocycles (eg, oxirane, oxetane, tetrahydrofuran, oxane, dioxane, etc.), S-containing heterocycles. Rings (for example, thiirane, thietane, tetrahydrothiophene, thiane, dithian etc.) can be exemplified.

  Ring Z is a substituent inert to the ether exchange reaction exemplified above (for example, halogen atom, alkyl group, alkoxy group, carboxyl group, acyl group, alkoxycarbonyl group, amino group, N-alkyl-substituted amino group, N- An acyl-substituted amino group and the like.

Examples of the alkylene group represented by X include the above-exemplified alkylene groups, for example, C _1-4 alkylene groups such as a methylene group.

  In ring Z, the substituent and the bonding site of X are not particularly limited. When two or more Xs are substituted on the ring Z, each X may be substituted at the same site, or may be substituted at different sites (such as o-, m-, and p-positions).

  m may be an integer of 1 or more, and may be, for example, 1 to 4, preferably 1 to 3, and more preferably about 1 or 2.

Examples of the alcohol represented by the formula (2a) include mono- or dihydroxy C _4-10 cycloalkane such as cyclopentanol and cyclohexanol; mono- or dihydroxy C _1-4 alkyl C _4-10 cycloalkane such as cyclopentanedimethanol. A 4- to 8-membered heterocycle substituted with a hydroxyl group such as mono- or dihydroxyoxetane, mono- or dihydroxytetrahydrofuran (oxygen atom-containing heterocycle, etc.); hydroxy C _1-4 such as oxetane mono- or dimethanol, tetrahydrofuran mono- or dimethanol Examples thereof include a 4- to 8-membered heterocyclic ring substituted with an alkyl group (such as an oxygen atom-containing heterocyclic ring).

These alcohols can be used alone or in combination of two or more. Of these alcohols, linear or branched C _4-20 alkanols and alcohols represented by formula (2a) are preferred.

  The boiling point of the alcohol is normal pressure, for example, 50 to 300 ° C, preferably 70 to 270 ° C, and more preferably about 100 to 250 ° C.

  (1) Vinyl ether and (2) alcohol may be used in a ratio of approximately equimolar equivalents, but (1) use of vinyl ether from the point of shifting the chemical equilibrium to the product side and improving the conversion rate of vinyl ether. The amount may be (2) an excess molar equivalent ratio relative to the alcohol. (1) The amount of vinyl ether used is, for example, (1-10) × mmol, preferably (2-9) × mmol, and more preferably (3-8) × 1 mol of alcohol. It may be on the order of millimoles (for example, (4-7) × mmol), and in a large excess ratio (for example, (6-25) × mmol, preferably (about 7-15) × mmol). There may be.

(Transition metal catalyst)
In the present invention, even if a transition metal catalyst whose activity tends to decrease at the reaction temperature or distillation temperature is used, the reaction or distillation is carried out while bubbling oxygen, so that the transition metal catalyst can be prevented from being deactivated. Therefore, the transition metal catalyst is not particularly limited as long as it has an action of promoting the ether exchange reaction.

  The transition metal catalyst may be a single transition metal, but is usually a compound containing a transition metal (transition metal compound). Examples of transition metals include Group 4 elements of the periodic table (eg, titanium, zirconium, hafnium, etc.), Group 5 elements of the periodic table (eg, vanadium, niobium, tantalum, etc.), and Group 6 elements of the periodic table (eg, chromium, molybdenum). , Tungsten, etc.), periodic table group 7 element (eg, manganese), periodic table group 8 element (eg, iron, ruthenium, etc.), periodic table group 9 element (eg, cobalt, rhodium, iridium, etc.), periodic table 10 Examples include group elements (for example, nickel, palladium, platinum, etc.), periodic table group 11 elements (for example, copper, silver, gold, etc.). These transition metals may be used alone or in combination of two or more. Among these transition metals, periodic table group 9-10 elements such as cobalt and palladium (in particular, periodic table group 10 elements such as palladium) are preferable. The valence of these elements (transition metals) is, for example, about 0 to 6, preferably about 1 to 6, and more preferably about 1 to 4 (for example, 2 to 4).

Examples of transition metal compounds include inorganic salts of transition metals [for example, inorganic acid salts (for example, nitrates, sulfates, sulfites, phosphates, phosphonates, perhalogenates such as perchlorates, chromates, etc. Etc.), halides (eg, chloride, bromide, iodide, etc.), oxides, sulfides, nitrides, hydroxides, etc.], organic acid salts [eg, carboxylates (eg, acetates, propionic acids, etc.) C _1-12 alkanates such as salts; halo C _1-4 alkanates such as dichloroacetic acid, trifluoroacetate, tribromoacetate), oxycarboxylates, thiocyanates, sulfonates], complexes (Or complex salt) can be exemplified.

Examples of the ligand constituting the complex (coordination compound) include OH (hydroxo), alkoxy group, acyl group, alkoxycarbonyl group, acetylacetonato (acac), trifluoroacetylacetonato, cycloalkadienyl group (Such as cyclopentadienyl group), halogen atom, CO, CN, oxygen atom, H ₂ O (aquo), phosphorus compound (such as phosphine), nitrogen compound [NH ₃ (ammine), NO, NO ₂ (nitro), NO ₃ (nitrato), C _2-4 alkylene diamines such as ethylene diamine, di C _2-4 alkylene triamines such as diethylene triamine, C _5-10 cycloalkane diamines such as cyclohexane diamine; nitrogen atoms such as pyridine, imidazole, bipyridine, phenanthroline Containing heterocyclic compounds] etc. It can be exemplified. These ligands may be used alone or in combination of two or more. The ligand may be a monodentate ligand, a bidentate ligand, or a tridentate or higher polydentate ligand.

Typical transition metal compounds (or organic transition metal compounds) include cobalt complexes [for example, acetylacetonate complexes such as Co (acac) ₂ and Co (acac) ₃ ; CoH (CO) ₄ and Co ₂ (CO) Carbonyl complexes such as ₈ ], palladium complexes [eg, phenanthroline complexes such as (1,10-phenanthroline) Pd; bipyridine complexes such as (2,2′-bipyridine) Pd; (ethylenediamine) Pd, (2,4- Pentanediamine) Pd, diamine complexes such as (1,2-cyclohexanediamine) Pd, etc.].

  These transition metal catalysts can be used alone or in combination of two or more. Of these transition metal catalysts, palladium compounds (such as palladium complexes) and cobalt compounds (such as cobalt complexes) are preferable, and palladium compounds (such as palladium complexes) are particularly preferable.

  The transition metal catalyst may be used by being supported on a conventional carrier (for example, a metal oxide such as silica, alumina, zeolite, etc.).

  The proportion of the transition metal catalyst is, for example, 0.001 to 15 parts by weight, preferably 0.01 to 12 parts by weight, more preferably 0.1 to 10 parts by weight (for example, 100 parts by weight of alcohol) 0.5 to 5 parts by weight). The ratio may be (1) a ratio relative to vinyl ether.

  The transition metal catalyst may be a commercially available product or may be prepared by a known method. The transition metal compound may be formed in the reaction system using a precursor of the transition metal compound. In the present invention, since the transition metal catalyst in the residue (concentrated residue) obtained by distilling off the low boiling point component from the reaction mixture of the reaction end liquid is not deactivated, the ether exchange reaction may be performed in the presence of this residue.

(solvent)
The ether exchange reaction can be performed in the presence or absence of a solvent. The solvent is not particularly limited and can be appropriately selected depending on the type of vinyl ether or alcohol. For example, aliphatic hydrocarbon (for example, linear or branched C _5-10 alkane such as hexane), alicyclic Hydrocarbons (eg, C _5-10 cycloalkanes such as cyclohexane and methylcyclohexane), aromatic hydrocarbons (eg, C _6-10 arenes such as toluene, xylene, etc.), halogenated hydrocarbons (eg, chloroform) Halo C _1-2 alkanes such as dichloromethane, dichloroethane; halo C _6-10 arenes such as mono or dichlorobenzene; halo C _1-2 alkyl C _6-10 arenes such as trifluoromethylbenzene), amides (eg Formamide, N, N-dimethylformamide, acetamide, N, Chain amides such as N-dimethylacetamide; cyclic amides such as N-methylpyrrolidone and 1,3-dimethyl-2-imidazolidinone), amines (for example, dibutylamine, triethylamine, N, N-dimethylisopropylamine, etc.) Di- or tri-C _1-4 alkylamines; C _2-4 alkylenediamines such as N, N, N ′, N′-tetramethylethylenediamine; C _6-10 arylamines such as N, N-dimethylaniline Cyclic amines such as piperidine, piperazine, pyridine and picoline), ketones (eg di-C _1-4 alkyl ketones such as acetone and methyl ethyl ketone; C _5-10 cycloalkanones such as cyclohexanone), esters (eg acetic acid); _{C 1-4} alkanoic acid _{C 1-4} alkyl such as ethyl; Vinegar _{C 6-10} arene-carboxylic acid _{C 1-4} alkyl such as methyl benzoate;; _{C 1-4} alkanoic acid _{C 6-10} aryl such as phenyl, lactone such as γ- butyrolactone), ethers (e.g., diethyl ether, etc. Di- _C1-4 alkyl ethers of (poly) _C2-4 alkylene glycol diethylene glycol dimethyl ether (monoglyme), diethylene glycol dimethyl ether (diglyme), triethylene glycol dimethyl ether (triglyme), tetraethylene glycol dimethyl ether (tetraglyme), etc. C _1-4 alkyl ethers; _{C 6-10} aryl _{C 1-4} alkyl ethers, such as anisole; _{C 5-10} cycloalkyl _{C 1-4} alkyl ethers such as cyclopentyl methyl ether Tetrahydrofuran, 1,4 and cyclic ethers such as dioxane), carbonates (e.g., _{di-C 1-4} alkyl carbonates such as dimethyl carbonate; _{C 2-4} such as ethylene carbonate; di _{C 6-10} aryl carbonates such as diphenyl carbonate Sulfur-containing compounds (eg, sulfoxides such as dimethyl sulfoxide; sulfones such as tetramethylene sulfone); Nitriles (eg, cyano C _1-2 alkanes such as acetonitrile, cyano C _6-10 arenes such as benzonitrile) Nitro compounds (for example, nitro C _1-2 alkanes such as nitromethane; nitro C _6-10 arenes such as nitrobenzene) and the like. These solvents can be used alone or as a mixed solvent. Of these solvents, poly C _2-4 alkylene glycol di C _1-4 alkyl ethers such as diglyme and tetraglyme are widely used.

  The solvent may be a component capable of forming an azeotropic mixture with respect to any of the components represented by the formulas (1) to (4).

  The proportion of the solvent may be, for example, 1 to 500 parts by weight, preferably 5 to 300 parts by weight, and more preferably about 10 to 250 parts by weight with respect to 100 parts by weight of (2) alcohol. The ratio may be (1) a ratio relative to vinyl ether.

  The ether exchange reaction may be carried out in the presence of other components inert to the reaction, for example, conventional additives (for example, polymerization inhibitors, stabilizers, etc.).

  The reaction temperature of the ether exchange reaction can be selected from the range of about −10 to 100 ° C. (for example, 0 to 95 ° C.), for example, 40 to 90 ° C., preferably 45 to 85 ° C. (for example, 50 to 80 ° C.), More preferably, it may be about 55 to 75 ° C. (for example, 60 to 70 ° C.). In particular, even if the reaction is carried out at a high temperature (for example, about 60 to 80 ° C.) in order to promote the reaction, the activity of the transition metal catalyst can be prevented from decreasing.

  The ether exchange reaction may be performed under normal pressure, increased pressure, or reduced pressure. When the ether exchange reaction is performed under pressure, the reaction rate can be improved, and when the ether exchange reaction is performed under reduced pressure, the low boiling point component can be efficiently distilled off, thereby increasing the reaction rate. In the case of reduced pressure, the degree of reduced pressure can be selected from a range of about 1 to 759 Torr. The reaction time may be, for example, 1 to 50 hours, preferably about 3 to 30 hours.

(3) Ether-exchanged vinyl ether (3) Ether-exchanged vinyl ether can be produced by the above reaction. In Formula (3), n can be selected from the same range as m. Moreover, mn should just be an integer of 0 or 1 or more, for example, 0-3, Preferably it is 0-2, More preferably, it is about 0 or 1. In the present invention, since the reaction efficiency is high, vinyl ether having mn of 0 can be efficiently produced.

  In the present invention, although the ether exchange reaction is an equilibrium reaction, the conversion rate (or yield) of vinyl ether is high. The conversion rate of vinyl ether is, for example, 50 to 100 mol% (for example, 55 to 99.9 mol%), preferably 60 to 100 mol%, more preferably 70 to 100 mol% (for example, 80 to 100 mol%). Degree. Even when (1) vinyl ether and (2) alcohol are reacted in the presence of a residue obtained by distilling a low-boiling component from the reaction mixture after completion of the reaction, the activity of the transition metal catalyst in the residue is high. Since it is hold | maintained, the conversion rate of vinyl ether can be selected from the same range as the above.

[Concentration step or distillation step]
In the present invention, the reaction mixture is concentrated (distilled) during the reaction, particularly after completion of the reaction, while bubbling oxygen through the reaction mixture. The reaction mixture consists of (1) unreacted vinyl ether, (2) unreacted alcohol, (3) produced vinyl ether, impurities by-produced during the reaction [eg, (4) by-product alcohol, etc.], transition metal catalyst, solvent, Contains additives and combinations thereof.

  The location for bubbling oxygen is not particularly limited, and may be, for example, a reaction mixture in a reaction vessel or a reaction mixture in a distillation column. In addition, as long as the transition metal catalyst is included, if it is a batch-type distillation, it may be bubbled in either the charging liquid or the kettle liquid. Bubbling may be performed. In the present invention, in order to prevent the deactivation of the transition metal catalyst, a solution containing at least the transition metal catalyst, for example, the reaction mixture in the reaction vessel, or the liquid to be distilled in the region from the charged portion of the distillation column to the bottom of the column is bubbled. Is preferred.

  The bubbling gas (supply gas) only needs to contain at least oxygen (molecular oxygen), may be pure oxygen, or may be a mixed gas of oxygen and an inert gas. Examples of the inert gas include nitrogen, carbon monoxide, carbon dioxide, and rare gases (such as helium and argon). These inert gases may be used alone or in combination of two or more. As a typical mixed gas, a gas containing oxygen and nitrogen (for example, air) can be exemplified.

  The oxygen concentration in the mixed gas is, for example, 0.1% or more (for example, 0.1 to 99.9%), preferably 1% or more (for example, 5 to 99%), and more preferably 10% or more (for example, 15 to 95%).

The bubbling speed (feeding speed) is, for example, 5 to 100 liters / minute, preferably 7 to 90 liters / minute with respect to 1 mole of the transition metal catalyst with respect to 1 mole of the catalyst, in terms of O ₂ , at room temperature Preferably, it is about 10-80 liters / minute. The bubbling speed in the reaction step is 0.1 to 100 liters / minute, preferably 0.2 to 80 liters / minute (for example, with respect to 1 mol of the substrate (2) alcohol in terms of O ₂ at room temperature). 0.3 to 50 liters / minute), more preferably about 0.4 to 40 liters / minute (for example, 0.5 to 20 liters / minute). Note that oxygen may be supplied continuously or intermittently.

  The dissolved oxygen concentration of the reaction mixture during the concentration step is not particularly limited and may be 100 ppm or more (for example, about 130 to 150 ppm), but is usually less than 100 ppm, for example, 0.0001 to 60 ppm, preferably 0. 0.001 to 30 ppm, more preferably about 0.01 to 10 ppm (for example, 0.01 to 5 ppm). The dissolved oxygen concentration often shows a saturation solubility (almost 0) at the concentration temperature, and may be below the detection limit (for example, less than 0 to 1 ppm). The dissolved oxygen concentration can be measured by a conventional method such as a diaphragm electrode method (galvanic cell method, polarographic method, etc.).

  While bubbling oxygen as described above, the low boiling point component in the reaction mixture is distilled off from the reaction system at the distillation temperature, and the low boiling point component and the high boiling point component are separated. The low boiling point component is a component that volatilizes at the distillation temperature among the components present in the reaction mixture. The low boiling point component often contains components other than the transition metal catalyst, for example, (1) unreacted vinyl ether and (4) by-product alcohol. Therefore, if low boiling point components are distilled out of the system during the reaction process, the chemical equilibrium shifts to the product side, and the conversion rate of vinyl ether can be improved.

  Moreover, the low boiling point component may contain (1) unreacted vinyl ether, (2) unreacted alcohol, (3) generated vinyl ether, and (4) by-product alcohol. If such a low boiling point component is distilled off after completion of the reaction, it can be reused without deactivating the transition metal catalyst.

  The distillation temperature (or the boiling point of the low-boiling component) is, for example, 50 to 100 ° C. (eg 50 to 90 ° C.), preferably 55 to 85 ° C. (eg 55 to 80 ° C.), more preferably 60 to 75 ° C. ( For example, about 60-70 degreeC) may be sufficient. The distillation temperature usually means the reaction temperature when distilling the low-boiling components in the reaction step. When distilling the low-boiling components after the completion of the reaction, the temperature at the bottom of the distillation column (bottle liquor or bottoms) Temperature). In the present invention, the reaction and the concentration can be performed while preventing the transition metal catalyst from being deactivated regardless of the temperature condition. Further, in the present invention, since the activity of the transition metal catalyst can be prevented from being lowered even if the distillation temperature is increased, the distillation efficiency can be increased, and the temperature difference from the cooling temperature is increased to efficiently condense the low boiling point components. The recovered low boiling point components can be reused.

  Distillation may be performed under normal pressure or reduced pressure. The degree of vacuum can be selected from the same range as the reaction step (for example, about 1 to 759 Torr). In the present invention, deactivation of the transition metal catalyst can be prevented even by distillation at a relatively low degree of vacuum (about 1 to 5 Torr) and at a relatively high temperature (about 60 to 80 ° C.).

  Distillation can be performed using a conventional distillation apparatus (distillation tower), for example, a rectifying tower such as a plate tower (perforated plate tower, bubble bell tower, etc.), a packed tower, or the like. As the distillation method, a batch method (batch method) in which a predetermined amount of a mixture is charged into a distillation system and distilled may be performed. A semi-batch method or a continuous distillation in which a predetermined amount of a mixture is continuously introduced into the distillation system. You may do it by a formula. The distillation method may be simple distillation (for example, flash distillation) or molecular distillation (for example, pot-type molecular distillation, falling film molecular distillation, centrifugal molecular distillation, etc.). The flash distillation can be performed using a conventional apparatus [for example, a thin film distillation apparatus (for example, WFE (Wiped Film Evaporator), FFE (Falling Film Evaporator), etc.), etc.).

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

Example 1
In a 30 mL three-necked flask equipped with a Dimroth condenser, Pd (OAc) ₂ 270 mg (1.20 mmol), 2,2′-bipyridyl 1.87 g (12.0 mmol), tetraglyme 10.4 g, oxetane dimethanol 4.74 g (40 mmol) and 6.90 g (80 mmol) of n-propyl vinyl ether were added, and vinylation reaction was carried out at 50 ° C. for 4 hours. When the liquid after the reaction was analyzed by gas chromatography, the conversion rate of oxetane dimethanol was 59%, the yield of oxetane dimethanol monovinyl ether was 50%, and the yield of oxetane dimethanol divinyl ether was 9%. It contained 4.5 g of n-propyl vinyl ether and 1.5 g of reaction by-product n-propanol.

  Next, heating was started in an oil bath while bubbling in the solution at a flow rate of 120 ml / min with 20% oxygen, and n-propyl vinyl ether and n-propanol were concentrated at normal pressure. did. The kettle liquid temperature during the distillation was 65 ° C., and the dissolved oxygen concentration in the reaction liquid was less than 1 ppm. When the concentrated liquid after distillation was analyzed by gas chromatography, it contained 0.1 g of n-propyl vinyl ether and 0.1 g of n-propanol. The liquid after distillation was a deep red-yellow solution, and no black insoluble precipitate was observed. When the amount of Pd in the solution was quantified by ICP (Inductively Coupled Plasma) emission analysis, no decrease in the Pd content was observed.

Comparative Example 1
The vinylation reaction was carried out in the same manner as in Example 1. Subsequently, a distillation operation similar to that in Example 1 was started without carrying out bubbling of 20% oxygen in the reaction end solution, and after 5 minutes, the reaction solution started to turn black. A precipitate was generated. The black precipitate was removed by filtration through a 0.20 μm polytetrafluoroethylene (PTFE) cartridge filter, and then the amount of Pd in the filtrate was quantified by ICP emission analysis. As a result, it was found to be 78% of the amount used in the reaction. It was falling.

Example 2
In a 30 mL three-necked flask equipped with a Dimroth condenser, 404 mg (1.8 mmol) of Pd (OAc) _2, 2.81 g (18.0 mmol) of 2,2′-bipyridyl, 9.8 g of acetonitrile, 1-butanol 4 .45 g (60 mmol) and 10.3 g (120 mmol) of n-propyl vinyl ether were added, and the vinylation reaction was carried out at 60 ° C. for 6 hours. When the liquid after the reaction was analyzed by gas chromatography, the conversion rate from 1-butanol to n-butyl vinyl ether was 90%.

  Next, the reaction-terminated liquid was set under reduced pressure, heating was started in an oil bath while bubbling 20% oxygen at a flow rate of 180 ml / min, and the mixture was concentrated to dryness at a bath temperature of 65 ° C. The dissolved oxygen concentration of the reaction solution during concentration was less than 1 ppm. No black precipitate was observed during the concentration, and the concentrated residue showed a deep yellow color. The residue was charged with the same weight of acetonitrile, 1-butanol, and n-propyl vinyl ether as the first time, and the same reaction as the first time was performed. As a result, the conversion rate of 1-butanol was 89% after 6 hours of reaction. There was no decrease in activity due to recycling of the residue.

Comparative Example 2
After the first vinylation reaction was carried out in the same manner as in Example 2, the same distillation operation as in Example 2 was started without carrying out 20% oxygen bubbling in the reaction completion liquid. After 10 minutes, The reaction liquid started to turn black, and the concentrated residue at the end of concentration to dryness was black.

  The residue was charged with the same weight of acetonitrile, 1-butanol, and n-propyl vinyl ether as the first time, and the same reaction as the first time was performed, but a black precipitate was present in the reaction solution, and the reaction time was 6 hours later. The conversion of was 18%.

Example 3
In a 200 mL four-necked flask equipped with a dropping funnel, a distillation line, and a condenser, 0.9 g (4 mmol) of Pd (OAc) ₂ , 6.22 g (40 mmol) of 2,2′-bipyridyl, oxetane dimethanol 16 .2 g (0.14 mol), 113 g (1.3 mol) of n-propyl vinyl ether, 12.2 g of diglyme, and bubbling 20% oxygen at 350 mL / min. The reaction was carried out while distilling off propyl vinyl ether and by-product n-propanol. Since the amount of the reaction solution decreased as the solvent was distilled off, n-propyl vinyl ether was replenished from the dropping funnel so as to maintain the amount of the solution at the time of preparation. The dissolved oxygen concentration of the reaction solution during the reaction was less than 1 ppm. After 24 hours, the reaction mixture was analyzed by gas chromatography. The conversion of oxetane dimethanol was 100%, the yield of oxetane dimethanol monovinyl ether was 10%, and the yield of oxetane dimethanol divinyl ether was 80%. there were. Moreover, the precipitation of the black insoluble matter was not recognized.

Comparative Example 3
Except not carrying out 20% oxygen bubbling, the reaction was carried out in the same procedure as in Example 3 under the heating condition of the reaction temperature of 65 ° C. while distilling off n-propyl vinyl ether and by-product n-propanol. One hour after the start of the reaction, black precipitation began to occur, and the reaction did not proceed after the conversion rate of oxetane dimethanol reached 70% after a reaction time of 13 hours.

Example 4
In a 100 mL three-necked flask equipped with a Dimroth condenser, 135 mg (0.60 mmol) of Pd (OAc) ₂ , 1.79 g (11.4 mmol) of 2,2′-bipyridyl, 4.17 g (40 mmol) of neopentyl glycol ), 32.7 g (380 mmol) of n-propyl vinyl ether was added, and vinylation reaction was carried out at 50 ° C. for 15 hours. When the liquid after the reaction was analyzed by gas chromatography, the conversion rate of neopentyl glycol was 97%, the yield of neopentyl glycol monovinyl ether was 32%, and the yield of neopentyl glycol divinyl ether was 65%. And 27.1 g of n-propyl vinyl ether and 3.8 g of reaction by-product n-propanol.

  Next, heating was started in an oil bath while bubbling in the solution at a flow rate of 120 ml / min with 20% oxygen, and n-propyl vinyl ether and n-propanol were concentrated at normal pressure. did. The kettle liquid temperature during the distillation was 65 ° C., and the dissolved oxygen concentration in the reaction liquid was less than 1 ppm. When the concentrated liquid after distillation was analyzed by gas chromatography, it contained 0.1 g of n-propyl vinyl ether and 0.1 g of n-propanol. The liquid after distillation was a deep red-yellow solution, and no black insoluble precipitate was observed. When the amount of Pd in the solution was quantified by ICP analysis, no decrease in the Pd content was observed.

Example 5
In a 100 mL three-necked flask equipped with a Dimroth condenser, 135 mg (0.60 mmol) of Pd (OAc) ₂ , 94 mg (0.60 mmol) of 2,2′-bipyridyl, 31.5 g of tetraglyme, oxetane dimethanol 73 g (40 mmol) and 32.7 g (380 mmol) of n-propyl vinyl ether were added, and vinylation reaction was carried out at 50 ° C. for 6 hours. When the liquid after the reaction was analyzed by gas chromatography, the conversion rate of oxetane dimethanol was 59%, the yield of oxetane dimethanol monovinyl ether was 53%, and the yield of oxetane dimethanol divinyl ether was 6%. It contained 30.4 g of n-propyl vinyl ether and 1.5 g of reaction by-product n-propanol.

  Next, heating was started in an oil bath while bubbling in the solution at a flow rate of 120 ml / min with 20% oxygen, and n-propyl vinyl ether and n-propanol were concentrated at normal pressure. did. The kettle liquid temperature during the distillation was 65 ° C., and the dissolved oxygen concentration in the reaction liquid was less than 1 ppm. When the concentrated liquid after distillation was analyzed by gas chromatography, it contained 0.1 g of n-propyl vinyl ether and 0.1 g of n-propanol. The liquid after distillation was a deep red-yellow solution, and no black insoluble precipitate was observed. When the amount of Pd in the solution was quantified by ICP analysis, no decrease in the Pd content was observed.

Example 6
The reaction solution obtained in Example 3 was heated in an oil bath while bubbling 20% oxygen at a flow rate of 350 mL / min, and n-propyl vinyl ether and n-propanol were distilled off at 65 ° C. at normal pressure. Carried out. When the distillation of n-propyl vinyl ether and n-propanol was completed, the distillation apparatus was started to depressurize and oxetane dimethanol divinyl ether was distilled off at a reduced pressure of 2.3 Torr. 10.5 g of oxetane dimethanol divinyl ether was obtained as a fraction in the boiling range of 70 to 78 ° C. The temperature of the pot liquid at the end of the distillation was 80 ° C. The dissolved oxygen concentration of the reaction solution during distillation was less than 1 ppm. The liquid after completion of the distillation was a deep red solution, and no black insoluble precipitate was observed.

  In the present invention, the conversion rate of the ether exchange reaction is high, the recyclability of the raw material components is excellent, and vinyl ether can be mass-produced industrially at low cost. The obtained vinyl ether can be suitably used as materials in various fields, for example, materials for paints, inks, adhesives or adhesives, photosensitive resins, resists, plate making, lithography, holograms and the like.

Claims (10)

  In the presence of a transition metal catalyst, (1) a reaction of vinyl ether with (2) alcohol, and (3) a method of producing vinyl ether produced by ether exchange, wherein oxygen is added to the reaction mixture during or after the reaction step. A method for producing vinyl ether, in which a low-boiling component is distilled to concentrate the reaction mixture while bubbling.   The process according to claim 1, wherein the low-boiling components are distilled at 50 to 100 ° C.   (2) The method according to claim 1 or 2, wherein (1) vinyl ether is used in an excess molar equivalent ratio with respect to alcohol.   The method according to any one of claims 1 to 3, wherein oxygen is bubbled at a rate of 5 to 100 l / min with respect to 1 mol of the transition metal catalyst.   In the presence of a transition metal catalyst, (1) vinyl ether and (2) alcohol are reacted using (1) vinyl ether in a ratio of 6 to 25-fold molar equivalent to 1 mol of alcohol; (3) A method for producing vinyl ether produced by ether exchange, wherein during the reaction step or after the completion of the reaction, oxygen is bubbled into the reaction mixture at a rate of 10 to 80 liters / min with respect to 1 mol of the catalyst, A method for producing vinyl ether, comprising distilling at 60 to 80 ° C. to concentrate the reaction mixture.   The method according to any one of claims 1 to 5, wherein the transition metal catalyst is a palladium complex and / or a cobalt complex.   The method according to any one of claims 1 to 6, wherein the transition metal catalyst is a palladium complex. (1) The vinyl ether is at least one selected from C _1-6 alkyl vinyl ether and C _2-6 alkenyl vinyl ether,
(2) The alcohol is a linear or branched C _4-20 alkanol and the following formula (2a)

(In the formula, ring Z is a C _4-10 aliphatic hydrocarbon ring or a 4- to 8-membered heterocyclic ring containing at least one hetero atom selected from a nitrogen atom, an oxygen atom and a sulfur atom as a constituent atom of the ring. X represents a C _1-4 alkylene group, m is an integer of 1 to 4, and p is 0 or 1.
Is at least one selected from alcohols represented by:
The method according to any one of claims 1 to 7, wherein the low-boiling component contains (1) unreacted vinyl ether and (4) alcohol produced as a by-product in the reaction.   The method according to any one of claims 1 to 8, wherein (1) vinyl ether and (2) alcohol are reacted in the presence of a residue obtained by distilling a low-boiling component from the reaction mixture after completion of the reaction.   A method of concentrating a reaction mixture formed by reacting (1) vinyl ether and (2) alcohol in the presence of a transition metal catalyst, wherein a low-boiling component is distilled while oxygen is bubbled through the reaction mixture. Concentration method to give out.