JP2009167129A - Alcohol production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method capable of efficiently producing an alcohol having an extended carbon chain from a primary alcohol with a small amount of catalyst.
SOLUTION: The alcohol production method of the present invention is a method in which a primary alcohol is dimerized in the presence of a group 8-10 element compound of the periodic table, a phosphine-based ligand and a base, and the carbon chain is elongated. It is characterized by obtaining. Primary alcohols include ethanol, 1-propanol, and 1-butanol. The periodic table 8-10 group element compound includes an iridium compound. The amount of the group 8-10 element compound used in the periodic table is preferably less than 0.1 mol% with respect to the primary alcohol.
[Selection figure] None

Description

  The present invention relates to a process for producing an alcohol using a periodic table group 8-10 element compound catalyst, more specifically, a primary alcohol is dimerized using a periodic table group 8-10 element compound catalyst, and the carbon chain is The present invention relates to a method for producing elongated alcohol.

  It has been reported that group 8-10 element compounds of the periodic table such as iridium complexes show high catalytic activity in hydrogen transfer reactions, and are used in organic synthetic chemistry. Japanese Patent Application Laid-Open No. 2004-262786 discloses a method for producing a carbonyl compound having an extended carbon chain or an alcohol that is a reduced form thereof by reacting a carbonyl compound with an alcohol in the presence of a group 9 element compound of the periodic table and a base. It is disclosed. However, in this method, the carbonyl compound is the main product, and the yield of alcohol is not so high. In Organic Letters, 2005, 7, 4017-4019, a β-alkylation reaction of a secondary alcohol with a primary alcohol using an iridium catalyst is reported. However, even in this method, the yield of alcohol is not necessarily high.

  Japanese Patent Application Laid-Open No. 2007-223947 discloses a method in which a primary alcohol is dimerized in the presence of a group 8-10 element compound of the periodic table and a base to obtain an alcohol having an extended carbon chain. . However, in this method, the amount of the target compound produced per unit catalyst amount is small, and it cannot be said that the method is sufficiently satisfactory from an industrial standpoint.

JP 2004-262786 A JP 2007-223947 A Organic Letters, 2005, 7, 4017-4019

  Accordingly, an object of the present invention is to provide a method capable of efficiently producing an alcohol having an extended carbon chain from a primary alcohol even with a small amount of catalyst.

  As a result of intensive studies to achieve the above-mentioned object, the present inventors have found that when a primary alcohol is subjected to a dimerization reaction in the presence of a periodic table group 8-10 element compound, a phosphine-based ligand and a base, a catalyst is obtained. The present invention has been completed by finding that an alcohol having an extended carbon chain can be efficiently produced even with a small amount of.

  That is, the present invention is characterized in that a primary alcohol is subjected to a dimerization reaction in the presence of a group 8-10 element compound of the periodic table, a phosphine-based ligand and a base to obtain an alcohol having an extended carbon chain. A method for producing alcohol is provided.

  Primary alcohols include ethanol, 1-propanol, and 1-butanol. The iridium compound is contained in the periodic table group 8-10 element compound. The usage-amount of a periodic table 8-10 group element compound is less than 0.1 mol% with respect to a primary alcohol, for example.

  According to the production method of the present invention, an alcohol having an extended carbon chain can be produced from a primary alcohol under a mild condition by a catalytic reaction with a high yield. Further, the catalyst has a large turnover number, and a large amount of the target compound can be obtained with a small amount of catalyst.

[Primary alcohol]
The primary alcohol used as a raw material may be any of aliphatic alcohols, aromatic alcohols, alicyclic alcohols, heterocyclic alcohols, etc. A monohydric alcohol may be used. As the primary alcohol, a compound in which one or two (particularly two) hydrogen atoms are bonded to the carbon atom at the β-position of the hydroxyl group is preferable. Primary alcohols can be used alone or in combination of two or more.

（式中、Ｒは水素原子又は有機基を示す） A typical primary alcohol includes a compound represented by the following formula (1).

(In the formula, R represents a hydrogen atom or an organic group)

  The organic group may be any group that does not inhibit this reaction. For example, a hydrocarbon group, a heterocyclic group, a substituted oxycarbonyl group (alkoxycarbonyl group, aryloxycarbonyl group, aralkyloxycarbonyl group, cyclohexane, Alkyloxycarbonyl group, etc.), carboxyl group, substituted or unsubstituted carbamoyl group, cyano group, acyl group (aliphatic acyl group such as acetyl group; aromatic acyl group such as benzoyl group), and two or more of these bonded Groups and the like. The carboxyl group or the like may be protected with a protective group known or commonly used in the field of organic synthesis, and may be substituted with a metal.

  The hydrocarbon group and the heterocyclic group also include a hydrocarbon group and a heterocyclic group having a substituent. The hydrocarbon group includes an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a group in which these are bonded. Examples of the aliphatic hydrocarbon group include 1 to 20 carbon atoms (preferably 1 to 1) such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, s-butyl, t-butyl, pentyl, hexyl, decyl, and dodecyl groups. 10, more preferably an alkyl group of about 1 to 3); an alkenyl group of about 2 to 20 carbon atoms (preferably 2 to 10, more preferably 2 to 3) such as vinyl, allyl, 1-butenyl group; Examples thereof include alkynyl groups having about 2 to 20 carbon atoms (preferably 2 to 10, more preferably 2 to 3) such as propynyl groups.

As the alicyclic hydrocarbon group, a cycloalkyl group having about 3 to 20 members (preferably 3 to 15 members, more preferably 5 to 8 members) such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and cyclooctyl groups; Cycloalkenyl groups of about 3 to 20 members (preferably 3 to 15 members, more preferably 5 to 8 members) such as pentenyl and cyclohexenyl groups; perhydronaphthalen-1-yl group, norbornyl, adamantyl, tetracyclo [4 4.0.1, ^2,5 . 1 ^7,10 ] bridged cyclic hydrocarbon groups such as dodecan-3-yl groups. Examples of the aromatic hydrocarbon group include aromatic hydrocarbon groups having about 6 to 14 (preferably 6 to 10) carbon atoms such as phenyl and naphthyl groups.

The hydrocarbon group in which an aliphatic hydrocarbon group and an alicyclic hydrocarbon group are bonded includes a cycloalkyl-alkyl group such as cyclopentylmethyl, cyclohexylmethyl, 2-cyclohexylethyl group (for example, C _3-20 cycloalkyl- C _1-4 alkyl group and the like). The hydrocarbon group in which an aliphatic hydrocarbon group and an aromatic hydrocarbon group are bonded to each other includes an aralkyl group (for example, a C _7-18 aralkyl group) and an alkyl-substituted aryl group (for example, about 1 to about 4). A phenyl group substituted with a C _1-4 alkyl group or a naphthyl group).

Preferred hydrocarbon groups include C _1-10 alkyl groups, C _2-10 alkenyl groups, C _2-10 alkynyl groups, C _3-15 cycloalkyl groups, C _6-14 aromatic hydrocarbon groups, C _3-15 A cycloalkyl-C _1-4 alkyl group, a C _7-14 aralkyl group and the like are included.

  The hydrocarbon group includes various substituents such as halogen atoms, oxo groups, hydroxyl groups, substituted oxy groups (for example, alkoxy groups, aryloxy groups, aralkyloxy groups, acyloxy groups, etc.), carboxyl groups, substituted oxycarbonyls. Groups (alkoxycarbonyl groups, aryloxycarbonyl groups, aralkyloxycarbonyl groups, etc.), substituted or unsubstituted carbamoyl groups, cyano groups, nitro groups, acyl groups, substituted or unsubstituted amino groups, sulfo groups, heterocyclic groups, etc. You may have. The hydroxyl group and carboxyl group may be protected with a protective group commonly used in the field of organic synthesis. In addition, an aromatic or non-aromatic heterocycle may be condensed with the ring of the alicyclic hydrocarbon group or aromatic hydrocarbon group.

The heterocyclic ring constituting the heterocyclic group as the organic group in R includes an aromatic heterocyclic ring and a non-aromatic heterocyclic ring. Examples of such a heterocyclic ring include a heterocyclic ring containing an oxygen atom as a hetero atom (for example, 5-membered ring such as furan, tetrahydrofuran, oxazole, isoxazole, and γ-butyrolactone ring, 4-oxo-4H-pyran, tetrahydro 6-membered ring such as pyran, morpholine ring, condensed ring such as benzofuran, isobenzofuran, 4-oxo-4H-chromene, chroman, isochroman ring, 3-oxatricyclo [4.3.1.1 ^4,8 ] undecane 2-one ring, a bridged ring such as 3-oxatricyclo [4.2.1.0 ^4,8 ] nonan-2-one ring), a heterocycle containing a sulfur atom as a hetero atom (for example, thiophene, 5-membered ring such as thiazole, isothiazole, thiadiazole ring, 6-membered ring such as 4-oxo-4H-thiopyran ring, benzothiophene ring Any fused ring), heterocycles containing nitrogen atoms as heteroatoms (eg, 5-membered rings such as pyrrole, pyrrolidine, pyrazole, imidazole, triazole rings, 6-membered rings such as pyridine, pyridazine, pyrimidine, pyrazine, piperidine, piperazine rings) Ring, indole, indoline, quinoline, acridine, naphthyridine, quinazoline, a condensed ring such as a purine ring, etc.). In addition to the substituents that the hydrocarbon group may have, the heterocyclic group includes an alkyl group (eg, a C _1-4 alkyl group such as a methyl or ethyl group), a cycloalkyl group, an aryl group It may have a substituent such as (for example, phenyl, naphthyl group).

  As typical examples of primary alcohols used as raw materials, ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, 1-decanol, 1 -Aliphatic alcohols such as dodecanol; aromatic alcohols such as 2-phenylethyl alcohol, 3-phenylpropyl alcohol, 4-phenylbutyl alcohol; 2-cyclohexylethyl alcohol, 2-cyclopentylethyl alcohol, 3-cyclohexylpropyl alcohol, 4 -Alicyclic alcohols such as cyclohexylbutyl alcohol; heterocyclic alcohols such as 2- (pyridin-2-yl) ethyl alcohol and 2- (furan-2-yl) ethyl alcohol; 1,3-propanediol, 1, 4 Butanediol, and polyhydric alcohols such as diols, such as 1,6-hexanediol. As the primary alcohol, a monovalent aliphatic alcohol having 2 to 6 carbon atoms is preferable, and ethanol, 1-propanol, and 1-butanol are particularly preferable.

[Group 8-10 element compound of the periodic table]
In this invention, the periodic table group 8-10 element compound (a metal simple substance is included) is used as a catalyst. The periodic table group 8 element (metal) includes iron, ruthenium, and osmium. The periodic table group 9 element (metal) includes cobalt, rhodium, and iridium. In addition, the Group 10 element (metal) of the periodic table includes nickel, palladium, and platinum. Periodic table 8-10 group element compounds include a wide range of inorganic and organic compounds containing 8-10 group elements of the periodic table. Examples of the inorganic compound include simple metals, oxides, sulfides, hydroxides, halides, sulfates, oxo acids containing 8 to 10 group elements of the periodic table, or salts thereof, and inorganic complexes. Examples of the organic compound include cyanide, organic acid salt (such as acetate), and organic complex. Among these, organic compounds such as organic complexes are preferable. The ligand of the complex includes a known ligand. The valence of the group 8-10 element in the group 8-10 element compound of the periodic table is about 0-6, preferably 0-3. In particular, in the case of an iridium compound, monovalent or trivalent is preferable. The periodic table 8-10 group element compound can be used individually or in combination of 2 or more types.

  A typical example of a periodic table group 8-10 element compound is shown by taking iridium as an example. As an inorganic iridium compound, for example, metal iridium, iridium oxide, iridium sulfide, iridium hydroxide, iridium fluoride, iridium chloride, odor Iridium iodide, iridium iodide, iridium sulfate, iridium acid or a salt thereof (for example, potassium iridate), inorganic iridium complex [for example, hexaammineiridium (III) salt, chloropentammineiridium (III) salt, etc.] Can be mentioned.

As the organic iridium compound, for example, an organic iridium complex can be used in addition to iridium cyanide. Examples of the organic iridium complex include tris (acetylacetonato) iridium, dodecacarbonyltetrairidium (0), chlorotricarbonyliridium (I), di-μ-chlorotetrakis (cyclooctene) diiridium (I) ([IrCl (Coe) ₂ ] ₂ ), di-μ-chlorotetrakis (ethylene) diiridium (I), di-μ-chlorobis (1,5-cyclooctadiene) diiridium (I) ([IrCl (cod)] ₂ ), Di-μ-hydroxybis (1,5-cyclooctadiene) diiridium (I) ([IrOH (cod)] ₂ ), (acetylacetone) (1,5-cyclooctadiene) iridium (I) ([ Ir (acac) (cod)]), di-μ-methoxybis (1,5-cyclooctadiene) diiridium (I) ([I r (OMe) (cod)] ₂ ), di-μ-chlorodichlorobis (1,2,3,4,5-pentamethylcyclopentadienyl) diiridium (III) ([Cp ^* IrCl ₂ ] ₂ ) , Trichlorotris (triethylphosphine) iridium (III), pentahydridobis (trimethylphosphine) iridium (V), chlorocarbonylbis (triphenylphosphine) iridium (I), chlorotris (triphenylphosphine) iridium (I) (IrCl ( PPh ₃ ) ₃ ), chloroethylenebis (triphenylphosphine) iridium (I), (pentamethylcyclopentadienyl) dicarbonyliridium (I), bis {1,2-bis (diphenylphosphino) ethane} iridium ( I) Chloride, pentamethylcyclopentadienylbis (eth ) Iridium (I), carbonylmethylbis (triphenylphosphine) iridium (I), (1,5-cyclooctadiene) (diphosphine) iridium (I) halide, 1,5-cyclooctadiene (1,2 -Bis (diphenylphosphino) ethane) iridium (I) hexafluorophosphate, (1,5-cyclooctadiene) bis (trialkylphosphine) iridium (I) halide, bis (1,5-cyclooctadiene ) Iridium tetrafluoroborate ([Ir (cod) ₂ ] ⁺ BF ₄ ⁻ ), (1,5-cyclooctadiene) (acetonitrile) iridium tetrafluoroborate, and the like.

Preferred iridium compounds include iridium complexes. Among these, organic iridium complexes, in particular, unsaturated hydrocarbons such as cyclopentene, dicyclopentadiene, cyclooctene, 1,5-cyclooctadiene, ethylene, pentamethylcyclopentadiene, benzene, toluene; nitriles such as acetonitrile; Ethers such as tetrahydrofuran; organic iridium complexes having phosphines such as triphenylphosphine as a ligand [for example, di-μ-chlorotetrakis (cyclooctene) diiridium (I), di-μ-chlorotetrakis (ethylene) Diiridium (I), di-μ-chlorobis (1,5-cyclooctadiene) diiridium (I) ([IrCl (cod)] ₂ ), di-μ-hydroxybis (1,5-cyclooctadiene) Diiridium (I) ([IrOH (cod) _2), (acetylacetone) (1,5-cyclooctadiene) iridium (I) ([Ir (acac) (cod)]), di -μ- methoxybis (1,5-cyclooctadiene) diiridium (I) ([Ir (OMe) (cod)] ₂ ), di-μ-chlorodichlorobis (1,2,3,4,5-pentamethylcyclopentadienyl) diiridium (III) ([Cp ^* IrCl ₂ ] ₂ ), bis (1,5-cyclooctadiene) iridium tetrafluoroborate, (1,5-cyclooctadiene) (acetonitrile) iridium tetrafluoroborate and the like] are preferable.

  Examples of Group 8-10 element compounds other than iridium compounds include compounds corresponding to the above iridium compounds [for example, dichlorobis (1,5-cyclooctadiene) dirhodium, etc.], literatures, etc. For example, the 4th edition experimental chemistry course 17 and 18, published by Maruzen Co., Ltd.). In the periodic table group 8-10 element compounds other than iridium, for example, unsaturated hydrocarbons such as cyclopentene, dicyclopentadiene, cyclooctene, 1,5-cyclooctadiene, ethylene, pentamethylcyclopentadiene, benzene, toluene; Particularly preferred are organic complexes having nitriles such as acetonitrile; ethers such as tetrahydrofuran; and phosphines such as triphenylphosphine as ligands. Among group 8-10 element compounds of the periodic table, group 9 elements of the periodic table are preferable. Further, platinum group element (ruthenium, rhodium, palladium, osmium, iridium, platinum) compounds are also preferable, and iridium compounds are particularly preferable.

  The group 8-10 element compound of the periodic table can be used as it is or in a form supported on a carrier. Examples of the carrier include conventional carriers for supporting a catalyst, for example, metal oxides such as silica, alumina, silica-alumina, zeolite, titania, and magnesia, and activated carbon. In the carrier-supported catalyst, the amount of the group 8-10 element compound supported on the periodic table is, for example, about 0.1 to 50% by weight, preferably about 1 to 20% by weight, based on the carrier. The catalyst can be supported by a conventional method such as an impregnation method, a precipitation method, or an ion exchange method.

  The amount of Group 8-10 element compound used in the periodic table can be appropriately selected depending on the type of raw material, the type of catalyst, and the like, but is generally less than 1 mol% (for example, 0%) with respect to the primary alcohol used as the raw material. 0.0001 mol% or more and less than 1 mol%), preferably less than 0.1 mol% (for example, 0.0005 mol% or more and less than 0.1 mol%), more preferably less than 0.05 mol% (0.001 mol%). % Or more and less than 0.05 mol%). In the present invention, since a phosphine-based ligand is used, the amount of the target compound produced per unit catalyst amount is large. Therefore, the target alcohol can be efficiently obtained with a small amount of catalyst.

  The catalyst can be recovered (reactivated if necessary) and reused. For example, the reaction liquid containing a catalyst (Group 8-10 element compound of the periodic table) is obtained as it is, or the residual liquid obtained by subjecting the reaction liquid to distillation, or obtained by subjecting the reaction liquid to other physical treatment. The mixture can be subjected to ion exchange resin treatment to adsorb the catalyst, and then the catalyst can be recovered by desorbing the catalyst using a desorbing water-soluble solvent. This method is particularly useful when the catalyst is an organometallic complex.

  As the ion exchange resin used for the ion exchange resin treatment, a cation exchange resin, an anion exchange resin, or the like can be used, but a strong acidic cation exchange resin or a strongly basic anion exchange resin is preferable. Adsorption efficiency can be improved by pre-treating the ion exchange resin before use. As the pretreatment, when a cation exchange resin is used, it can be washed with an aqueous solution adjusted to be acidic with hydrochloric acid or the like. When an anion exchange resin is used, an alkaline aqueous solution (for example, hydroxylation) is used. It can be carried out by washing with a sodium aqueous solution, a potassium hydroxide aqueous solution or the like. The processing temperature by ion exchange resin is 0-100 degreeC, for example. When using a strongly acidic cation exchange resin, it is preferable to use an acidic alcohol (methanol, ethanol, isopropanol, n-butanol, etc. adjusted to be acidic with an aqueous acid solution such as dilute hydrochloric acid) as a desorbing water-soluble solvent. When a strongly basic anion exchange resin is used, the reaction solution containing the catalyst is distilled, and the resulting residual solution is subjected to alkali treatment (for example, sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, sodium methoxide- It is preferable to apply a treatment with a methanol solution or the like, subject the residual solution after the alkali treatment to anion exchange resin treatment, and use an aqueous alkali solution (sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, etc.) as a desorbing water-soluble solvent. . The temperature of the alkali treatment is, for example, 20 to 80 ° C. When performing the alkali treatment, it is preferable that an oxidizing agent such as oxygen or hydrogen peroxide is present. Note that the positively charged catalyst as a whole is adsorbed on the cation exchange resin. Moreover, by performing the alkali treatment, the catalyst is negatively charged and is adsorbed on the anion exchange resin.

[Phosphine ligand]
In this invention, a phosphine-type ligand is used with the said periodic table 8-10 group element compound. Examples of the phosphine-based ligand include monocycloalkyl ligands such as tricycloalkylphosphine such as tricyclohexylphosphine, trialkylphosphine such as trimethylphosphine and tributylphosphine, and triarylphosphine such as triphenylphosphine; 1,2- Bis (diphenylphosphino) ethane, 1,3-bis (diphenylphosphino) propane (dppp), 1,4-bis (diphenylphosphino) butane (dppb), 2,3-bis (diphenylphosphino) butane, etc. And bidentate ligands such as bis (diarylphosphino) alkanes. Among these, bis (diarylphosphino) alkane is preferable, and 1,3-bis (diphenylphosphino) propane (dppp) is particularly preferable. A phosphine-type ligand can be used individually or in combination of 2 or more types.

  The amount of the phosphine-based ligand used can be appropriately selected within a range that does not inhibit the reaction, but is generally about 0.2 to 10 mol, preferably 1 mol per mol of the group 8-10 element compound in the periodic table. It is about 0.4-3 mol.

  The amount of the phosphine-based ligand used is, for example, less than 1 mol% (for example, 0.0001 mol% or more and less than 1 mol%), preferably 0.1 mol%, with respect to the primary alcohol used as a raw material. It is less than (for example, 0.0005 mol% or more and less than 0.1 mol%), more preferably less than 0.05 mol% (0.001 mol% or more and less than 0.05 mol%).

[base]
In this invention, a base is used with the said periodic table 8-10 group element compound and a phosphine-type ligand. The base may be any of an inorganic base, an organic base, a Lewis base and the like, and a base usually used for aldol condensation is preferable.

  Examples of the inorganic base include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, potassium hydroxide, and cesium hydroxide; alkali metal carbonates such as lithium carbonate, sodium carbonate, potassium carbonate, and cesium carbonate; hydrogen carbonate Alkali metal hydrogen carbonates such as sodium, potassium hydrogen carbonate and cesium hydrogen carbonate; Alkaline earth metal hydroxides such as magnesium hydroxide, calcium hydroxide and barium hydroxide; Alkaline earth such as magnesium carbonate, calcium carbonate and barium carbonate Metal carbonates; cerium carbonate and the like.

  Examples of the organic base include alkali metal alkoxides such as sodium methoxide, sodium ethoxide and potassium t-butoxide; alkali metal organic acid salts such as sodium acetate; amines such as triethylamine, piperidine, N-methylpiperidine and pyridine ( Tertiary amines) and nitrogen-containing heterocyclic compounds.

  Moreover, a solid base can also be used as a base. Examples of the solid base include hydroxyapatite, hydrotalcite, magnesia, zirconia and the like. These can also be used as the catalyst carrier.

  Of these, strong bases such as alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; alkali metal alkoxides such as potassium t-butoxide are particularly preferable.

The amount of the base added varies depending on the type of raw material and the periodic table group 8-10 element compound, etc., but is usually about 0.01-0.7 mol, preferably 1 mol of primary alcohol used as the raw material. Is about 0.05 to 0.5 mol.
[Hydrogen acceptor]
In the present invention, a hydrogen acceptor may be present in the reaction system in order to further improve the yield of the target alcohol. The hydrogen acceptor is not particularly limited, and examples thereof include alkadienes such as butadiene, isoprene and 1,7-octadiene; cycloalkadienes such as 1,5-cyclooctadiene; alkenes such as propylene and 1-octene. Cycloalkenes such as cyclooctene; nitrobenzene; carbonyl compounds (aldehyde or ketone) such as propionaldehyde, crotonaldehyde, and acetone.

  The amount of the hydrogen acceptor used can be appropriately selected within a range that does not inhibit the reaction. However, in general, it is 0.15 mol or less (for example, 0.0005 to 0.005 per mol of primary alcohol used as a raw material). About 15 mol), preferably 0.12 mol or less (for example, about 0.001 to 0.12 mol), more preferably 0.1 mol or less (for example, about 0.002 to 0.1 mol).

[reaction]
The dimerization reaction of the primary alcohol is performed in the presence or absence of a solvent. Examples of the solvent include aliphatic hydrocarbons such as hexane, heptane, and octane; alicyclic hydrocarbons such as cyclohexane; aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene; chloroform, dichloromethane, 1,2- Halogenated hydrocarbons such as dichloroethane; ethers such as diethyl ether, dimethoxyethane, tetrahydrofuran and dioxane; amides such as N, N-dimethylformamide and N, N-dimethylacetamide. These solvents are used alone or in admixture of two or more. In the present invention, the reaction proceeds smoothly without using a solvent.

In the reaction system, an aldehyde corresponding to the primary alcohol used as a raw material [for example, an aldehyde represented by R—CH ₂ —CHO when the alcohol represented by the formula (1) is used as a raw material] A small amount may be added. The reaction rate may be improved by adding the aldehyde.

  The reaction may be performed in the presence of a polymerization inhibitor. The reaction temperature can be appropriately selected according to the reaction raw material, the type of catalyst, and the like, and is, for example, 20 to 200 ° C., preferably 50 to 180 ° C., more preferably about 70 to 150 ° C., and the reaction time is, for example, 5 to 5 ° C. 48 hours, preferably about 10 to 24 hours. In the present invention, the mixture of reaction raw materials is stirred at a temperature of 20 ° C. or higher and lower than 50 ° C. for about 0.1 to 10 hours (preferably about 0.2 to 5 hours), and then 50 to 180 ° C. (preferably 70 ° C.). When the mixture is stirred at about 150 ° C. for about 5 to 24 hours (preferably about 10 to 20 hours), the turnover number of the catalyst is greatly improved.

  The reaction may be carried out at normal pressure or under reduced pressure or increased pressure. The reaction atmosphere is not particularly limited as long as it does not inhibit the reaction. For example, the reaction is preferably performed in an inert gas atmosphere such as a nitrogen atmosphere or an argon atmosphere. Note that the presence of a small amount of oxygen may cause the oxygen to function as a hydrogen acceptor and increase the reaction rate. However, as will be described later, when excess oxygen is present in the system, other reactions are likely to proceed. Become. Therefore, it is desirable that the oxygen concentration in the gas phase part of the reaction system is, for example, 10% or less, preferably 5% or less, more preferably 1% or less. The order of addition of the reaction raw materials, the catalyst and the like is not particularly limited, and the reaction can be performed by any method such as a batch method, a semi-batch method, or a continuous method.

（式中、Ｒは前記に同じ）
で表される炭素鎖の伸長したアルコールが生成する。 In the method of the present invention, even with a small amount of catalyst, the reaction produces a good yield of an alcohol in which the primary alcohol is dimerized and the carbon chain is extended under mild conditions. For example, when the primary alcohol represented by the formula (1) is used as a raw material, the following formula (2)

(Wherein R is the same as above)
An alcohol having an extended carbon chain represented by

  Although the reaction mechanism is not necessarily clear, first, the primary alcohol is oxidatively dehydrogenated by the group 8-10 element compound of the periodic table to become an aldehyde (at this time, the group 8-10 element compound of the periodic table is hydrogenated). , Which causes an aldol-type condensation reaction to produce an α, β-unsaturated aldehyde, which is hydrogenated with the hydrogenated group 8-10 element compound of the periodic table, and an alcohol whose carbon chain is elongated. (At this time, the original periodic table 8-10 group element compound is regenerated). When two or more kinds of primary alcohols are used as raw materials, in addition to the dimerization reaction product between the same kind of alcohols, a cross reaction product obtained by reacting different kinds of alcohols can be produced.

（式中、Ｒは前記に同じ）
で表されるカルボン酸エステルが主生成物として得られる。この場合も、２種以上の第１級アルコールを原料として用いると、同種のアルコール同士が反応したカルボン酸エステルのほか、異種のアルコール同士が反応した交差反応生成物が生成しうる。この反応の反応機構としては必ずしも明らかではないが、前記のようにして生成したアルデヒド同士がカップリングして対応するエステルが生成するものと推測される。このカルボン酸エステルの生成割合は、特に、塩基として、炭酸ナトリウム等のアルカリ金属炭酸塩や炭酸水素ナトリウム等のアルカリ金属炭酸水素塩などの比較的弱い塩基を用いたときに増大する。なお、酸素としては、純粋な酸素のほか、空気や、酸素を窒素等の不活性ガスで希釈した混合ガスなどを使用できる。 In the above reaction, when oxygen-excess conditions are employed with respect to the raw material alcohol (other conditions are the same as described above), the primary alcohol used as the raw material and the carboxylic acid corresponding to the alcohol Esters tend to be the main product. For example, when the primary alcohol represented by the formula (1) is used as a raw material, the following formula (3)

(Wherein R is the same as above)
Is obtained as the main product. Also in this case, when two or more kinds of primary alcohols are used as raw materials, a cross-reaction product in which different alcohols react with each other in addition to carboxylic acid esters in which the same kinds of alcohols react can be generated. Although the reaction mechanism of this reaction is not necessarily clear, it is presumed that the aldehydes produced as described above are coupled to produce the corresponding ester. The production rate of this carboxylic acid ester increases particularly when a relatively weak base such as an alkali metal carbonate such as sodium carbonate or an alkali metal hydrogen carbonate such as sodium bicarbonate is used as the base. As oxygen, pure oxygen, air, or a mixed gas obtained by diluting oxygen with an inert gas such as nitrogen can be used.

  After completion of the reaction, the reaction product can be separated and purified by separation means such as filtration, concentration, distillation, extraction, crystallization, recrystallization, column chromatography, etc., or a separation means combining these.

  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
The reactor was charged with 10 mL (0.17 mol) of ethanol, di-μ-hydroxybis (1,5-cyclooctadiene) diiridium (I) ([IrOH (cod)] ₂ ) (0.1 mol% vs. ethanol). ), 1,3-bis (diphenylphosphino) propane (dppp) (0.1 mol% to ethanol), and potassium hydroxide (KOH) (20 mol% to ethanol), and an inert gas (nitrogen) atmosphere The mixture was stirred at 120 ° C. for 16 hours. After the reaction, the reaction solution was analyzed by gas chromatography. As a result, 12.3% of 1-butanol, 0.3% of 2-ethyl-butanol, 0.4% of 1-hexanol, and 0 of 2-ethyl-hexanol were obtained. .2% yield. In addition, a trace amount of 1-octanol was generated. The turnover per atom of iridium (Ir) was 62 (for 1-butanol).

Comparative Example 1
The reactor was charged with 10 mL (0.17 mol) of ethanol, di-μ-hydroxybis (1,5-cyclooctadiene) diiridium (I) ([IrOH (cod)] ₂ ) (0.1 mol% vs. ethanol). ) And potassium hydroxide (KOH) (20 mol% to ethanol) were added, and the mixture was stirred at 120 ° C. for 16 hours in an inert gas (nitrogen) atmosphere. As a result of analyzing the reaction solution by gas chromatography after the reaction, 1-butanol was produced in a yield of 2.8%. Further, trace amounts of 2-ethyl-butanol, 1-hexanol, 2-ethyl-hexanol, and 1-octanol were generated. The turnover per atom of iridium (Ir) was 14 (for 1-butanol).

Example 2
The reactor was charged with 10 mL (0.17 mol) of ethanol, di-μ-hydroxybis (1,5-cyclooctadiene) diiridium (I) ([IrOH (cod)] ₂ ) (0.05 mol% vs. ethanol). ), 1,3-bis (diphenylphosphino) propane (dppp) (0.05 mol% to ethanol), and potassium hydroxide (KOH) (20 mol% to ethanol), and an inert gas (nitrogen) atmosphere The mixture was stirred at 120 ° C. for 16 hours. As a result of analyzing the reaction solution by gas chromatography after the reaction, 1-butanol was 12.1%, 2-ethyl-butanol was 0.3%, 1-hexanol was 0.3%, and 2-ethyl-hexanol was 0. .1% yield. In addition, a trace amount of 1-octanol was generated. The turnover per atom of iridium (Ir) was 121 (for 1-butanol).

Example 3
The reactor was charged with 10 mL (0.17 mol) of ethanol, di-μ-hydroxybis (1,5-cyclooctadiene) diiridium (I) ([IrOH (cod)] ₂ ) (0.02 mol% vs. ethanol). ), 1,3-bis (diphenylphosphino) propane (dppp) (0.01 mol% to ethanol), and potassium hydroxide (KOH) (20 mol% to ethanol), and an inert gas (nitrogen) atmosphere The mixture was stirred at 120 ° C. for 16 hours. After the reaction, the reaction solution was analyzed by gas chromatography. As a result, 10.3% of 1-butanol, 0.2% of 2-ethyl-butanol, 0.3% of 1-hexanol, and 0 of 2-ethyl-hexanol were found. .2% yield. In addition, a trace amount of 1-octanol was generated. The turnover per atom of iridium (Ir) was 250 (for 1-butanol).

Example 4
The reactor was charged with 10 mL of ethanol (0.17 mol), di-μ-hydroxybis (1,5-cyclooctadiene) diiridium (I) ([IrOH (cod)] ₂ ) (0.01 mol% vs. ethanol). ), 1,3-bis (diphenylphosphino) propane (dppp) (0.01 mol% to ethanol), 1,7-octadiene (1 mol% to ethanol), and potassium hydroxide (KOH) (20 mol%) And ethanol), and the mixture was stirred at 120 ° C. for 16 hours in an inert gas (nitrogen) atmosphere. After the reaction, the reaction solution was analyzed by gas chromatography. As a result, 1-butanol was 18.9%, 2-ethyl-butanol was 1.5%, 1-hexanol was 1.7%, and 2-ethyl-hexanol was 0. 0.6% and 1-octanol was produced in a yield of 0.3%. The turnover per atom of iridium (Ir) was 945 (for 1-butanol).

Example 5
Instead of di-μ-hydroxybis (1,5-cyclooctadiene) diiridium (I) ([IrOH (cod)] ₂ ), di-μ-chlorobis (1,5-cyclooctadiene) diiridium ( The reaction was performed in the same manner as in Example 4 except that I) ([IrCl (cod)] ₂ ) (0.01 mol% to ethanol) was used. After the reaction, the reaction solution was analyzed by gas chromatography. As a result, 9.4% of 1-butanol, 2.4% of 2-ethyl-butanol, 1.8% of 1-hexanol, and 1 of 2-ethyl-hexanol were 1%. 0.0% and 1-octanol was produced in a yield of 0.6%. The turnover per atom of iridium (Ir) was 470 (for 1-butanol).

Example 6
Instead of di-μ-hydroxybis (1,5-cyclooctadiene) diiridium (I) ([IrOH (cod)] ₂ ), (acetylacetone) (1,5-cyclooctadiene) iridium (I) ( The reaction was carried out in the same manner as in Example 4 except that [Ir (acac) (cod)]) (0.02 mol% to ethanol) was used. After the reaction, the reaction solution was analyzed by gas chromatography. As a result, 1-butanol was 23.5%, 2-ethyl-butanol was 7.6%, 1-hexanol was 5.3%, 2-ethyl-hexanol was 3 .3% and 1-octanol was produced in a yield of 1.9%. The turnover per atom of iridium (Ir) was 1175 (for 1-butanol).

Example 7
Instead of di-μ-hydroxybis (1,5-cyclooctadiene) diiridium (I) ([IrOH (cod)] ₂ ), di-μ-methoxybis (1,5-cyclooctadiene) diiridium ( The reaction was carried out in the same manner as in Example 4 except that I) ([Ir (OMe) (cod)] ₂ ) (0.01 mol% to ethanol) was used. After the reaction, the reaction solution was analyzed by gas chromatography. As a result, 1-butanol was 12.6%, 2-ethyl-butanol was 3.9%, 1-hexanol was 2.4%, 2-ethyl-hexanol was 1 0.7% and 1-octanol was produced in a yield of 0.9%. The turnover per atom of iridium (Ir) was 630 (for 1-butanol).

Example 8
The reactor was charged with 10 mL (0.17 mol) of ethanol, (acetylacetone) (1,5-cyclooctadiene) iridium (I) ([Ir (acac) (cod)]) (0.01 mol% vs. ethanol), 1,3-bis (diphenylphosphino) propane (dppp) (0.01 mol% to ethanol), 1,7-octadiene (0.5 mol% to ethanol), and potassium hydroxide (KOH) (20 mol%) (To ethanol) was added, and the mixture was stirred at 120 ° C. for 16 hours in an inert gas (nitrogen) atmosphere. After the reaction, the reaction solution was analyzed by gas chromatography. As a result, 13.2% of 1-butanol, 2.7% of 2-ethyl-butanol, 1.7% of 1-hexanol, and 0 of 2-ethyl-hexanol were obtained. .4%, 1-octanol was produced in a yield of 0.2%. The turnover per atom of iridium (Ir) was 1320 (for 1-butanol).

Example 9
The reactor was charged with 10 mL (0.17 mol) of ethanol, (acetylacetone) (1,5-cyclooctadiene) iridium (I) ([Ir (acac) (cod)]) (0.02 mol% vs. ethanol), 1,3-bis (diphenylphosphino) propane (dppp) (0.01 mol% to ethanol), 1,7-octadiene (1 mol% to ethanol), and potassium hydroxide (KOH) (20 mol% to ethanol) The mixture was stirred at 25 ° C. for 0.5 hours in an inert gas (nitrogen) atmosphere and then stirred at 120 ° C. for 16 hours. After the reaction, the reaction solution was analyzed by gas chromatography. As a result, 1-butanol was 13.9%, 2-ethyl-butanol was 3.6%, 1-hexanol was 2.5%, 2-ethyl-hexanol was 1 0.5% and 1-octanol was produced in a yield of 0.9%. The turnover per atom of iridium (Ir) was 695 (for 1-butanol).

Example 10
The reactor was charged with 10 mL (0.17 mol) of ethanol, (acetylacetone) (1,5-cyclooctadiene) iridium (I) ([Ir (acac) (cod)]) (0.02 mol% vs. ethanol), 1,3-bis (diphenylphosphino) propane (dppp) (0.01 mol% to ethanol), 1,7-octadiene (1 mol% to ethanol), and potassium hydroxide (KOH) (20 mol% to ethanol) The mixture was stirred at 25 ° C. for 2 hours and then stirred at 120 ° C. for 16 hours in an inert gas (nitrogen) atmosphere. After the reaction, the reaction solution was analyzed by gas chromatography. As a result, 17.6% of 1-butanol, 3.6% of 2-ethyl-butanol, 2.9% of 1-hexanol, and 1 of 2-ethyl-hexanol were obtained. .4%, 1-octanol was produced in 0.9% yield. The turnover per atom of iridium (Ir) was 880 (for 1-butanol).

Example 11
The reactor was charged with 10 mL (0.17 mol) of ethanol, (acetylacetone) (1,5-cyclooctadiene) iridium (I) ([Ir (acac) (cod)]) (0.02 mol% vs. ethanol), Add triphenylphosphine (0.01 mol% vs ethanol), 1,7-octadiene (1 mol% vs ethanol), and potassium hydroxide (KOH) (20 mol% vs ethanol), inert gas (nitrogen) atmosphere Under stirring at 25 ° C. for 2 hours, the mixture was stirred at 120 ° C. for 16 hours. As a result of analyzing the reaction solution by gas chromatography after the reaction, 1-butanol was 11.1%, 2-ethyl-butanol was 1.3%, 1-hexanol was 2.1%, 2-ethyl-hexanol was 1 .4%, 1-octanol was produced in a yield of 0.4%. The turnover per atom of iridium (Ir) was 555 (for 1-butanol).

Example 12
The reactor was charged with 10 mL (0.17 mol) of ethanol, (acetylacetone) (1,5-cyclooctadiene) iridium (I) ([Ir (acac) (cod)]) (0.02 mol% vs. ethanol), 1,4-bis (diphenylphosphino) butane (dppb) (0.01 mol% to ethanol), 1,7-octadiene (1 mol% to ethanol), and potassium hydroxide (KOH) (20 mol% to ethanol) The mixture was stirred at 25 ° C. for 2 hours and then stirred at 120 ° C. for 16 hours in an inert gas (nitrogen) atmosphere. After the reaction, the reaction solution was analyzed by gas chromatography. As a result, 1-butanol was 13.4%, 2-ethyl-butanol was 1.9%, 1-hexanol was 2.3%, 2-ethyl-hexanol was 1 0.2%, 1-octanol was produced in a yield of 0.8%. The turnover per atom of iridium (Ir) was 664 (for 1-butanol).

Example 13
The reactor was charged with 15.6 mL (0.17 mol) of 1-butanol, di-μ-hydroxybis (1,5-cyclooctadiene) diiridium (I) ([IrOH (cod)] ₂ ) (0.01 Mol% to 1-butanol), 1,3-bis (diphenylphosphino) propane (dppp) (0.01 mol% to 1-butanol), and potassium hydroxide (KOH) (20 mol% to 1-butanol) And stirred at 120 ° C. for 16 hours under an inert gas (nitrogen) atmosphere. After the reaction, the reaction solution was analyzed by gas chromatography. As a result, 2-ethyl-hexanol was produced in a yield of 18.5%. In addition, a trace amount of 1-octanol was generated. The turnover per atom of iridium (Ir) was 925 (for 2-ethyl-hexanol).

Claims (4)

  A method for producing an alcohol, characterized in that a primary alcohol is subjected to a dimerization reaction in the presence of a group 8-10 element compound of the periodic table, a phosphine-based ligand, and a base to obtain an alcohol having an extended carbon chain.   The method for producing an alcohol according to claim 1, wherein the primary alcohol is ethanol, 1-propanol or 1-butanol.   The method for producing an alcohol according to claim 1 or 2, wherein the group 8-10 element compound of the periodic table is an iridium compound.   The method for producing an alcohol according to any one of claims 1 to 3, wherein the amount of the group 8-10 element compound in the periodic table is less than 0.1 mol% with respect to the primary alcohol.