WO2019163640A1 - Method for producing guerbet alcohol - Google Patents

Abstract

Disclosed is a method for producing a Guerbet alcohol, which includes the step of dimerizing at least one alcohol having a primary or secondary hydroxyl group and having 4 to 16 carbon atoms in the presence of transition metal nano-particles and a base to produce the Guerbet alcohol. The transition metal nano-particles are particles produced by heating a transition metal compound in a solvent containing a coordinating organic solvent.

Description

Method for producing Gerve alcohol

The present invention relates to a method for producing Gerve alcohol.

Gelbe alcohol is a β-branched alcohol produced by a Gelbe reaction that dimerizes an alcohol having a primary hydroxyl group or a secondary hydroxyl group, and is used industrially, for example, as a raw material for industrial and cosmetic purposes. For example, Patent Document 1 discloses a reaction in which a metal catalyst supported on a carrier such as carbon is used as a heterogeneous hydrogenation catalyst as a gel reaction for obtaining a gel alcohol. Heterogeneous metal catalysts are economically advantageous over homogeneous metal catalysts in that they can be recovered after the reaction is complete and easily reused.

Special table 2013-510105 gazette

However, in the conventional method using a heterogeneous metal catalyst, a high temperature such as 250 ° C. is required in order to advance the gel reaction. Accordingly, an object of one aspect of the present invention is to provide a method that makes it possible to obtain Gerve alcohol by a reaction at a lower temperature while using a metal catalyst that can be easily recovered after the reaction.

In one aspect of the present invention, one or two or more alcohols having 4 to 16 carbon atoms having a primary or secondary hydroxyl group are dimerized in the presence of transition metal nanoparticles and a base to obtain a gel gel. A method for producing Gerve alcohol comprising the step of producing alcohol is provided. The transition metal nanoparticles are particles generated by heating a transition metal compound in a solvent containing a coordinating organic solvent.

The transition metal nanoparticles used in this method can be easily recovered after completion of the reaction by ordinary methods such as distillation of the product and filtration. Further, according to this method, the dimerization of alcohol at a lower temperature can proceed to obtain Gerve alcohol.

According to the method of the present invention, gel alcohol can be obtained by reaction at a lower temperature while using a catalyst that can be easily recovered after the reaction.

Hereinafter, some embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.

In one embodiment of the method for producing Gerve alcohol, one or more alcohols having a primary or secondary hydroxyl group are dimerized by a Gerve reaction in the presence of transition metal nanoparticles and a base, Including the step of producing Gerve alcohol. Dimerization here means that the same kind of alcohol molecules or two different kinds of alcohol molecules react to produce Gerve alcohol. This may be dimerized using only one alcohol as starting material.

The starting alcohol may be any compound that has a primary or secondary hydroxyl group and can be dimerized to produce Gerve alcohol, and may be a linear alkyl alcohol. The carbon number of the starting alcohol is usually 4 to 16, but may be 8 or more.
It may be.

The starting alcohol can be, for example, a compound represented by the following formula (1).

In formula (1), R ¹ , R ² and R ³ each independently represent a linear, branched or cyclic saturated or unsaturated aliphatic group, and the number of carbon atoms of R ¹ , R ² and R ³ Is 2 to 14 in total. R ¹ may be a linear, branched or cyclic saturated or unsaturated aliphatic group having 2 to 12 carbon atoms, and R ² and R ³ may be a hydrogen atom. The aliphatic group herein may be a linear alkyl group.

Dimerization of the compound represented by the formula (1) produces, for example, Gerve alcohol represented by the formula (2). Each code | symbol in Formula (2) is synonymous with the code | symbol in Formula (1).

In the Gerve reaction in the method according to the present embodiment, the starting alcohol is oxidized to form a carbonyl compound, and the dimer having a carbonyl group and a carbon-carbon double bond by aldol condensation of two molecules of the carbonyl compound. It is presumed to include the production of a body and the addition of hydrogen to the dimer to produce Gerve alcohol. Transition metal nanoparticles are thought to be primarily responsible for the oxidation of alcohols and the addition of hydrogen to dimers. The base is believed to be primarily involved in aldol condensation.

The starting alcohol may be a linear alkyl alcohol, and specific examples thereof include 1-butanol, 1-hexanol, 1-octanol, 1-decanol, 1-dodecanol, 1-tetradecanol, 1- Hexadecanol and two combinations selected from these are mentioned.

The transition metal nanoparticles used as the metal catalyst are particles having a nano-size particle size and are considered to be metal cluster particles. The average particle diameter of the transition metal nanoparticles is, for example, 0.5 to 4 nm, and may be 2 nm or less. The particle diameter of the transition metal nanoparticles means the maximum width of the transition metal nanoparticles observed in, for example, a transmission electron microscope (TEM) image.

The transition metal nanoparticles can be particles generated by heating the transition metal compound in a solvent containing a coordinating organic solvent. It is considered that a coordinating organic solvent is disposed on the surface of the transition metal nanoparticle generated by this method, thereby protecting the transition metal nanoparticle. The transition metal nanoparticles can be synthesized with reference to, for example, a method described in JP2011-12097A.

The transition metal compound used to obtain the transition metal nanoparticles can be, for example, a transition metal halide, sulfate, or nitrate. The transition metal may be at least one selected from the group consisting of ruthenium, iridium, palladium, rhodium, and copper, and may be ruthenium or iridium in particular. Transition metal nanoparticles containing ruthenium or iridium (ruthenium nanoparticles or iridium nanoparticles) can be obtained by heating the ruthenium compound or iridium compound in a solvent containing a coordinating organic solvent. The valence of the transition metal contained in the transition metal compound is not particularly limited. For example, the ruthenium compound used to obtain ruthenium nanoparticles may contain trivalent ruthenium (Ru (III)), tetravalent ruthenium (Ru (IV)), or both.

The coordinating organic solvent used for obtaining the transition metal nanoparticles is an organic solvent capable of coordinating with the transition metal. The coordinating organic solvent is selected from, for example, an amide solvent, an amine solvent, an alcohol solvent, an ether solvent, a ketone solvent, an ester solvent, a nitrile solvent, a nitro solvent, a sulfoxide solvent, or these. It can be a combination of two or more. Examples of amide solvents include N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMA), 1,3-dimethyl-2-imidazolidinone (DMI), and N-methyl-2- Examples thereof include carboxylic acid amides such as pyrrolidone (NMP) and phosphoric acid amides such as hexamethylphosphoric triamide (HMPA). Examples of the amine solvent include triethylamine, pyridine and ethanolamine. Examples of alcohol solvents include isopropanol and propylene glycol. Examples of ether solvents include diethyl ether, diisopropyl ether, dioxane, and tetrahydrofuran (THF). Examples of the ketone solvent include acetone and 2-butanone. Examples of the ester solvent include ethyl acetate and methyl acetate. An example of a nitrile solvent is acetonitrile. An example of a nitro solvent is nitromethane. An example of the sulfoxide solvent is dimethyl sulfoxide. The coordinating organic solvent may be an amide solvent, particularly N, N-dimethylformamide.

After transition metal nanoparticles are formed in a solvent containing a coordinating organic solvent, the transition metal nanoparticles protected with the coordinating organic solvent are taken out from the obtained dispersion, and this is used as a catalyst for the Guerbe reaction. Can be used as Alternatively, the dispersion may be added as it is, or if necessary, after being concentrated into the system for the Gerve reaction.

The base used for the Gerbe reaction may contain an alkali metal or alkaline earth metal hydroxide, alkoxide or hydride. Examples of bases include potassium tert-butoxide, sodium ethoxide, sodium methoxide, potassium hydroxide, and sodium hydroxide.

The gel reaction for dimerizing alcohol can be performed in a solvent-free reaction mixture containing alcohol, transition metal nanoparticles and base, or in a reaction solution containing a solvent. The Gerve reaction in a solvent-free reaction mixture tends to produce the desired Gerve alcohol with higher yield and selectivity. However, the solventless reaction mixture may contain a trace amount of solvent. For example, the content of the solvent based on the mass of the reaction mixture may be 3% by mass or less, or 1% by mass or less.

When the Gelbe reaction is performed in a reaction solution containing a solvent, the solvent can be, for example, an alcohol solvent that does not dimerize such as t-butanol or isopropanol, or an ether solvent such as tetrahydrofuran. The content of the solvent in the reaction solution may be 0 to 200% by volume with respect to the volume of the starting alcohol.

The amount of transition metal nanoparticles used in the Gerbe reaction may be such that the ratio of ruthenium atoms to the total amount of starting alcohol is 0.01 to 1 mol%. The amount of the base may be 0.1 to 50 mol% with respect to the total amount of the starting alcohol.

When the reaction temperature (the temperature of the reaction mixture or reaction solution) of the Gelbe reaction for dimerizing alcohol is low, a relatively inexpensive heat source such as steam can be used, which is economically advantageous. In addition, there is a tendency that by-products are not easily generated. Therefore, the reaction temperature may be 190 ° C. or lower, 160 ° C. or lower, 150 ° C. or lower, or 140 ° C. or lower. According to the method according to the present embodiment, the Gerve reaction can be efficiently advanced even at such a low temperature. When the reaction temperature is 190 ° C. or lower, the reaction can efficiently proceed while suppressing thermal decomposition of the transition metal nanoparticles. The reaction temperature may be 40 ° C. or higher. In the gel reaction process, the reaction temperature may be changed. For example, the gel reaction process may include a relatively low temperature first stage and a relatively high temperature second stage. This tends to further improve the yield of gel alcohol. The reaction temperature in the first stage may be higher than the temperature at which the starting alcohol melts or dissolves. For example, the reaction temperature of the first stage may be 40 ° C. or more and less than 100 ° C., and the reaction temperature of the second stage may be 100 ° C. or more and 190 ° C. or less.

The total amount of starting alcohol may be mixed with the transition metal nanoparticles and the base at a time, or the alcohol may be mixed with the transition metal nanoparticles and the base a plurality of times (for example, twice). The upper limit of the number of times alcohol is introduced is not particularly limited, but may be, for example, 5 times or less, 4 times or less, or 3 times or less. When alcohol is introduced in a plurality of times, the yield of gel alcohol tends to be further improved. For example, after stirring the reaction mixture or reaction solution containing the alcohol, transition metal nanoparticles and base introduced in the first time, the second and subsequent alcohols may be introduced into the reaction mixture or reaction solution. In this case, the reaction mixture or reaction solution into which the first alcohol is introduced is stirred at a low temperature (for example, 40 ° C. or more and less than 100 ° C.), and the reaction mixture or reaction solution into which the second or later alcohol is introduced is heated to a higher temperature ( For example, you may stir at 100 degreeC or more and 190 degrees C or less. The amount of alcohol introduced at the first time may be smaller than the amount of alcohol introduced after the second time.

The gel reaction for dimerizing alcohol may be performed in an atmospheric pressure atmosphere. According to the method according to the present embodiment, the gel reaction can be efficiently advanced without requiring pressurization.

The reaction time of the Gerbe reaction may be adjusted within a range in which the reaction sufficiently proceeds, and may be, for example, 16 hours or longer, or 30 hours or longer, or 72 hours or shorter, or 48 hours or shorter. As described above, when the gel reaction process includes the first stage having a relatively low temperature and the second stage having a relatively high temperature, the reaction time of the second stage may be within these ranges.

After completion of the reaction, Gerve alcohol can be purified by a usual method if necessary. The transition metal nanoparticles can be taken out of the reaction mixture containing the reaction mixture or the solvent after the reaction is completed, and used again for the Gerube reaction. Alternatively, the alcohol of the starting material may be further added to the reaction mixture or reaction solution, and the Gerve reaction may be performed again.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

<Examination 1: Types of metal catalysts>
1-1. Synthesis of transition metal nanoparticles In a screw vial tube with a capacity of 20 mL, 0.2614 g (1 mmol) of ruthenium (III) chloride hydrate (manufactured by Wako Pure Chemical Industries, Ltd.), 9 mL of distilled water, and concentrated hydrochloric acid (Wako Pure Chemical Industries, Ltd.) 1 mL) was added and allowed to stand overnight at room temperature to obtain a ruthenium chloride aqueous solution containing ruthenium chloride at a concentration of 0.1M.

In a three-necked flask, 50 mL of N, N-dimethylformamide (DMF) was added. A reflux tube was attached to the three-necked flask, and the three-necked flask was heated in an oil bath heated to 140 to 142 ° C., and DMF was stirred. After 5 minutes from the start of heating, 500 μL of an aqueous ruthenium chloride solution was added. The heating and stirring for 10 hours were continued to produce ruthenium nanoparticles (ruthenium nanoclusters) dispersed in DMF. Thereafter, a dispersion containing ruthenium nanoparticles and DMF (calculated value of ruthenium concentration: 1 mM) was cooled to room temperature.

A dispersion containing iridium nanoparticles was obtained by the same procedure as above except that iridium (III) chloride hydrate was used instead of ruthenium (III) chloride hydrate.

1-2. Dimerization of 1-dodecanol using transition metal nanoparticles (Guerbe reaction)

1 mL of the above dispersion containing transition metal nanoparticles (ruthenium nanoparticles or iridium nanoparticles) was placed in a Schlenk tube, and DMF was distilled off by an evaporator. Into the Schlenk tube in which the transition metal nanoparticles protected by DMF remained, 0.2 mmol of potassium tert-butoxide (tBuOK) was added, and the atmosphere in the Schlenk tube was replaced with argon. The Schlenk tube was charged with 2 mmol of 1-dodecanol (1), and the Schlenk tube containing the reaction mixture was heated in an oil bath at 130 ° C. or 150 ° C. for 24 hours. After cooling, the reaction solution was diluted with diethyl ether, and dodecane as an internal standard was added to prepare a sample solution. This sample solution was analyzed by gas chromatography. Based on the peak area ratio in the obtained chromatogram, the consumption rate of the starting material 1-dodecanol and the resulting gelve alcohol (2) with respect to 1-dodecanol (1) Yield was calculated. Further, the ratio (selectivity) of 1-dodecanol to the entire product including by-products was determined based on the ratio of the peak area of the chromatogram.

For comparison, the same Gelbe reaction was performed using [Ru (p-cymene) Cl ₂ ] ₂ or ruthenium (III) chloride hydrate, which is a homogeneous metal complex catalyst, instead of transition metal nanoparticles. The product was analyzed by gas chromatography.

Table 1 shows the analysis results. It was confirmed that by the reaction in the presence of the transition metal nanoparticles and the base, the gel reaction proceeds sufficiently even at a relatively low temperature of 130 ° C. or 150 ° C., and gel alcohol is obtained. In the table, “nd” indicates that no peak was detected.

<Examination 2: Type of base>
1-dodecanol gel reaction was carried out under the same conditions as in Study 1 at 130 ° C. using tBuOK, potassium hydroxide (KOH), or sodium hydroxide (NaOH) as the base and ruthenium nanoparticles as the metal catalyst. . The starting material consumption rate, product yield and selectivity were measured by gas chromatography as in Study 1. The results are shown in Table 2.

Table 2 shows the analysis results. Even when any base was used, it was confirmed that the Gelbe reaction proceeded sufficiently at 130 ° C. In particular, potassium compounds tended to provide high yield and selectivity.

<Examination 3: Diluting solvent>
1 mL of a dispersion containing ruthenium nanoparticles was placed in a Schlenk tube, and DMF was distilled off by an evaporator. 0.2 mmol of potassium tert-butoxide (tBuOK) was placed in a Schlenk tube in which ruthenium nanoparticles protected by DMF remained, and the atmosphere in the Schlenk tube was replaced with argon. A Schlenk tube was charged with 2 mmol of 1-dodecanol and t-butanol (0.5 mL) or toluene (0.2 mL) as a solvent. While stirring the reaction solution, the Schlenk tube was heated at 130 ° C. for 24 hours with an oil bath. After cooling, dodecane as an internal standard was added to the reaction solution to prepare a sample solution. The sample solution was analyzed by gas chromatography to determine the starting material consumption rate, product yield and selectivity.

Table 3 shows the analysis results together with the results of the solvent-free reaction in Study 1. Even in the reaction in the reaction solution to which the solvent was added, it was confirmed that the Gelbe reaction proceeded at a low temperature of 130 ° C., although the yield was slightly lower than the reaction without solvent.

<Examination 4>
Synthesis test 4-1
In a four-necked flask, 800 mL of DMF was added. A reflux tube was attached to the four-necked flask, and DMF was stirred while the four-necked flask was heated to 140 to 142 ° C. When the internal temperature of the four-neck flask reached 140 ° C., 0.92 g of a ruthenium chloride solution (Tanaka Kikinzoku Kogyo Co., Ltd., ruthenium content: 8.35% by mass) was added. Heating and stirring were continued for 24 to 48 hours to produce ruthenium nanoparticles (ruthenium nanoclusters) dispersed in DMF. Thereafter, the dispersion containing ruthenium nanoparticles and DMF was cooled to room temperature.

375 mL of a dispersion containing ruthenium nanoparticles and DMF was placed in a four-necked flask, and DMF was distilled off under reduced pressure while heating to 120 ° C. Into a four-necked flask in which ruthenium nanoparticles protected by DMF remain, 135.5 g of 1-dodecanol and 4.13 g of potassium hydroxide (flakes, purity of 95%) are placed, and the atmosphere in the flask is changed to nitrogen. Replaced with. The reaction mixture in the flask was stirred for 3 hours while heating to 70-80 ° C. The reaction mixture was then stirred for 24 hours while heating to 150 ° C. Thereafter, a sample taken from the reaction mixture was diluted with methyl-tert-butyl ether. The diluted solution was analyzed by gas chromatography (GC), and based on the area ratio in the obtained chromatogram, the yield of the produced gelbe alcohol to 1-dodecanol was calculated.

Synthesis test 4-2
The reaction was carried out in the same manner as in Synthesis Test 4-1, except that the amount of the dispersion containing ruthenium nanoparticles was changed to 75 mL, and the yield of the produced gerbealcohol relative to 1-dodecanol was calculated.

Synthesis test 4-3
75 mL of the same dispersion containing ruthenium nanoparticles and DMF as in Synthesis Test 4-1 was placed in a four-necked flask, and DMF was distilled off under reduced pressure while heating to 120 ° C. To a four-necked flask in which ruthenium nanoparticles protected by DMF remain, 27.1 g of the first 1-dodecanol and 4.13 g of potassium hydroxide (flakes, purity 95%) were placed. The atmosphere was replaced with nitrogen. The reaction mixture in the flask was stirred for 3 hours while heating to 70-80 ° C. Next, 108.4 g of a second 1-dodecanol was added to the reaction mixture in the flask, and then the reaction mixture was stirred for 24 hours while heating to 150 ° C. A sample taken from the reaction mixture was then diluted with methyl-tert-butyl ether. The diluted solution was analyzed by gas chromatography (GC), and based on the area ratio in the obtained chromatogram, the yield of the produced gelbe alcohol to 1-dodecanol was calculated.

Test Examples 4-4 to 4-8
In the same manner as in Test Example 4-3, except that the type of alcohol and the amount of alcohol added in the second time were changed as shown in Table 4, gel alcohol was produced by adding alcohol in two portions. I let you. The yield of the resulting Gerbe alcohol relative to the starting alcohol was determined by GC analysis.

Test Examples 4-9 and 4-10
Gelbacoal was produced in the same manner as in Test Example 4-7 or 4-8, except that the temperature of the reaction mixture after the second alcohol addition was changed from 150 ° C. to 160 ° C. The yield of the resulting gerbealcohol relative to 1-tetradecanol or 1-hexadecanol was determined by GC analysis.

Table 4 shows the results. From a comparison between the synthesis test 4-1 and the results of the above-described Study 2, it was observed that the reaction mixture was stirred at a relatively low temperature and then heated to a high temperature to improve the yield of gel alcohol. . In addition, it was also confirmed that by introducing alcohol into the reaction mixture in two portions, gel alcohol was produced in a higher yield even when the amount of ruthenium nanoparticles was small.

<Examination 5>
Synthesis test 5-1
75 mL of the same dispersion containing ruthenium nanoparticles and DMF as in Synthesis Test 4-1 was placed in a four-necked flask, and DMF was distilled off under reduced pressure while heating to 120 ° C. To a four-necked flask in which ruthenium nanoparticles protected by DMF remain, 27.1 g of the first 1-decanol and 8.26 g of potassium hydroxide (flakes, purity of 95%) were placed. The atmosphere was replaced with nitrogen. The reaction mixture in the flask was stirred for 3 hours while heating to 70-80 ° C. Next, 243.9 g of a second 1-decanol was added to the reaction mixture in the flask, and then the reaction mixture was stirred for 48 hours while heating to 150 ° C. Samples taken from the reaction mixture after 24 hours and 48 hours of stirring were diluted with methyl-tert-butyl ether. The diluted solution was analyzed by gas chromatography (GC), and based on the area ratio in the obtained chromatogram, the yield of the produced gelbe alcohol with respect to 1-decanol was calculated.

Synthesis test 5-2, 5-3
Synthesis test 5 except that 1-tetradecanol (myristyl alcohol) or 1-hexadecanol (cetanol) was used as the alcohol, and the amounts of the ruthenium nanoparticle dispersion and alcohol were changed as shown in Table 5. The gel reaction similar to 1 was performed, and the yield of gel alcohol was determined by GC analysis.

 

 

Claims (7)

Comprising a step of dimerizing one or more alcohols having 4 to 16 carbon atoms having a primary or secondary hydroxyl group in the presence of a transition metal nanoparticle and a base to produce a gel alcohol. ,
The transition metal nanoparticles are particles generated by heating a transition metal compound in a solvent containing a coordinating organic solvent.
A method for producing Gerve alcohol. The method according to claim 1, wherein the transition metal nanoparticles are ruthenium nanoparticles or iridium nanoparticles produced by heating a ruthenium compound or an iridium compound in a solvent containing a coordinating organic solvent. 3. The method according to claim 1 or 2, wherein the base comprises an alkali metal or alkaline earth metal hydroxide, alkoxide or hydride. The method according to any one of claims 1 to 3, wherein the alcohol is dimerized in a solvent-free reaction mixture containing the alcohol, the transition metal nanoparticles and the base. The method according to any one of claims 1 to 4, wherein the alcohol is dimerized at a temperature of 190 ° C or lower. The method according to any one of claims 1 to 5, wherein the alcohol is dimerized under an atmospheric pressure atmosphere. The method according to any one of claims 1 to 6, wherein the alcohol is mixed with the transition metal nanoparticles and the base in a plurality of times.