JP6010787B2 - Catalyst for acetylation of alcohol, and method for producing acetylated product of alcohol using the catalyst - Google Patents

Description

  The present invention relates to an alcohol acylation catalyst capable of producing an acylated alcohol in a selective and high yield by acylating the alcohol, and a method for producing an acylated alcohol using the catalyst.

  As concerns about the supply of fossil fuels and global warming due to carbon dioxide emissions have become more serious, the use of biodiesel fuel derived from biological resources has begun to spread. However, although a large amount of glycerol is by-produced in the production process of biodiesel fuel, an effective utilization method of glycerol has not been established yet. Therefore, there is a strong demand for conversion of glycerol into useful compounds.

  An acylation reaction is known as one of glycerol conversion reactions. In the acylation reaction, glycerol is produced in a mixed state of mono-, di-, and triacylglycerols. Here, mono-, di-, and triacylglycerols are used as additives (for example, emulsifiers, plasticizers, solvents, etc.) in a wide range of compounds from cosmetics to gasoline. Monoacylglycerol and diacylglycerol are also useful as raw materials for antifreeze and biodegradable polymers.

  Regarding the acylation method of glycerol, Patent Document 1 describes a method of reacting glycerol and acetic acid in the absence of a catalyst. However, in particular, to obtain triacylglycerol, the reaction time was as long as about 50 hours, and the yield was not satisfactory.

  Patent Document 2 describes a method for producing triacylglycerol by reacting glycerol and acetic acid in the presence of a sulfuric acid catalyst, and adding and reacting glycerol and diacylglycerol remaining after the reaction with acetic anhydride. . However, acetic anhydride is expensive, and the work process and the treatment of excess acetic anhydride are complicated.

  Patent Document 3 describes a method for acylating glycerol using an acidic ion exchange resin as a catalyst. However, as described above, there are problems in that expensive acetic anhydride is used as an acylating agent and that the treatment of excess acetic anhydride is complicated.

  Patent Document 4 describes a method for acylating glycerol using a metal oxide such as tin oxide, zinc oxide, or tungsten oxide as a catalyst. However, it has been difficult to selectively produce mono, di, or triacylglycerols.

Japanese Unexamined Patent Publication No. 63-27456 German Patent Invention No. 156803 Specification JP 63-30429 A JP-A-8-27061

  Accordingly, an object of the present invention is to provide an alcohol acylation catalyst capable of selectively producing an acyl acylate in high yield with an efficient and simple method using an alcohol and an inexpensive carboxylic acid as raw materials. And providing a method for producing an acylated product of alcohol using the catalyst to produce an acylated product of alcohol.

  As a result of intensive studies to solve the above problems, the present inventors have used as a catalyst a compound obtained by converting a cation such as sodium ion or calcium ion present between montmorillonite crystal layers into lanthanum (III) ions. The present inventors have found that an acylated product of alcohol can be efficiently and easily produced using alcohol and inexpensive carboxylic acid as raw materials. Furthermore, it has been found that an acylated product of a specific alcohol can be produced very selectively by adjusting the reaction temperature and reaction time. The present invention has been completed based on these findings.

  That is, the present invention provides a catalyst for acylating an alcohol in which lanthanum (III) ions are immobilized between montmorillonite crystal layers.

  The lanthanum (III) ion is preferably immobilized in an amount of 1 to 10% by weight based on the total amount of the catalyst.

  The present invention also provides a method for producing an acylated product of alcohol by reacting an alcohol with a carboxylic acid in the presence of the catalyst for acylating the alcohol to obtain an acylated product of the alcohol.

  In the method for producing an acylated product of alcohol according to the present invention, it is preferable to adjust the reaction temperature in the range of 70 to 200 ° C. and the reaction time in the range of 1 to 36 hours.

  Further, the reaction is preferably performed in the presence of an aromatic hydrocarbon solvent.

Since the catalyst for acylating an alcohol of the present invention (hereinafter sometimes referred to as “catalyst”) has the above-described structure, an acylated product can be obtained efficiently and selectively by reacting the alcohol with an inexpensive carboxylic acid. Can do. Furthermore, the catalyst of the present invention can be easily separated from the product and can be reused repeatedly while retaining high catalytic activity. Therefore, the production cost of the acylated product of alcohol can be reduced, which is extremely advantageous for industrialization.
According to the method for producing an acylated product of alcohol of the present invention, useful mono-, di-, or triacylglycerol is efficiently produced in a simple process using glycerol produced as a by-product in the production process of biodiesel fuel. It is possible to suppress the increase in carbon dioxide emissions that cause global warming by effectively utilizing biological resources.

[Catalyst for acylation of alcohol]
The catalyst of the present invention has lanthanum (III) ions immobilized between montmorillonite crystal layers.

Montmorillonite is a layered silicate mineral and has, as a basic structure, a crystal layer composed of a three-layer laminate of silicate tetrahedral layer / alumina octahedral layer / silicate tetrahedral layer. The crystal layer is negatively charged because a part of aluminum as a central atom is replaced with magnesium, resulting in insufficient positive charge. Therefore, the shortage of charge is neutralized by placing a cation selected from alkali metal ions such as Na ⁺ and K ⁺ and alkaline earth metal ions such as Ca ²⁺ and Mg ²⁺ between the crystal layers, and a stable state is obtained. A structure is formed in which crystal layers are stacked so as to overlap each other.

As the montmorillonite of the present invention, it is particularly preferable to use a montmorillonite having Na ⁺ between crystal layers (that is, sodium-type montmorillonite) in terms of easy ion exchange. Sodium-type montmorillonite is represented by, for example, [Na _2/3 Si ₈ (Al _10/3 (Mg, Fe) _2/3 ) O _20. (OH) ₄ ].

  The montmorillonite in the present invention is not particularly limited, and commercially available products [for example, trade name “Kunipia F” (manufactured by Kunimine Industries, Ltd.)] can be used.

  The catalyst of the present invention can be produced, for example, by converting cations (preferably sodium ions) present between montmorillonite crystal layers to lanthanum (III) ions. Conversion of cations existing between the crystal layers to lanthanum (III) ions can be performed, for example, by treating montmorillonite with a solution containing a lanthanum salt (preferably, impregnation treatment).

Examples of the lanthanum salt include lanthanum trifluoromethanesulfonate (La (OTf) ₃ ), lanthanum acetate (La (OAc) ₃ ), lanthanum acetylacetonate (La (acac) ₃ ), lanthanum nitrate (La (NO _{3) 3} ), lanthanum chloride (LaCl ₃ ), lanthanum bromide (LaBr ₃ ) and the like. The concentration of the solution containing the lanthanum salt is, for example, about 5 to 100 mmol / L, preferably 10 to 80 mmol / L, and particularly preferably 20 to 50 mmol / L. When the concentration of the solution containing the lanthanum salt is lower than the above range, the conversion amount of lanthanum (III) ions decreases, and the conversion rate of glycerol tends to decrease. On the other hand, if the concentration of the solution containing the lanthanum salt exceeds the above range, it tends to be uneconomical.

  As temperature at the time of processing with the solution containing a lanthanum salt, it is about 20-80 degreeC, for example, Preferably it is 30-60 degreeC. When the processing temperature exceeds the above range, an apparatus for cooling the solvent vapor may be required. Further, when the processing temperature is below the above range, the exchange rate tends to decrease. The processing time with the solution containing the lanthanum salt is, for example, about 1 to 36 hours. When the treatment time is less than the above range, ion exchange tends to be insufficient. The treatment with the solution containing the lanthanum salt can be performed in an air atmosphere, a nitrogen atmosphere, an argon atmosphere, or the like, for example.

  Thereafter, the catalyst obtained by the above production method may be subjected to a washing treatment (washing with water, an organic solvent or the like), a drying treatment (drying by vacuum drying or the like), or the like.

  The content of lanthanum (III) ions in the catalyst obtained by the above method is, for example, about 1 to 10% by weight, preferably 2 to 8% by weight, particularly preferably 4 to 7% by weight, based on the total amount of the catalyst. When the content of lanthanum (III) ions is below the above range, the conversion rate of glycerol tends to decrease. On the other hand, when the content of lanthanum (III) ions exceeds the above range, lanthanum oxide clusters are formed, and the catalytic ability tends to decrease.

[Method for producing acylated product of alcohol]
The method for producing an acylated product of alcohol according to the present invention is characterized in that an alcohol acylated product is obtained by reacting an alcohol with a carboxylic acid in the presence of the above-mentioned alcohol acylating catalyst.

  Examples of the alcohol include aliphatic alcohols having about 1 to 10 carbon atoms (preferably 1 to 5) [for example, methanol, ethanol, 1-propanol, 1-butanol, 2-methylpropanol, 1-pentanol, 1 -Monovalent aliphatic alcohols such as hexanol, 1-heptanol, 2-ethyl-1-hexanol, 1-octanol, 1-decanol; divalent fats such as ethylene glycol, propylene glycol, trimethylene glycol, hexamethylene glycol Trihydric aliphatic alcohols such as glycerol], alicyclic alcohols having about 3 to 10 carbon atoms (preferably 3 to 7) [for example, cyclohexylmethyl alcohol, 2-cyclohexylethyl alcohol, glucose, fructose], 7-30 carbon atoms Preferably about 7-18) aromatic alcohol [for example, benzyl alcohol, 2-phenylethyl alcohol, 3-phenylpropyl alcohol, 3-phenyl-2-propen-1-ol], polymeric polyhydric alcohol (for example, Cellulose) and the like. These can be used alone or in combination of two or more.

  In the present invention, the use of glycerol produced as a by-product in the production process of biodiesel fuel as an alcohol increases the amount of carbon dioxide emissions that cause global warming by effectively utilizing biological resources. It is preferable at the point which can suppress.

  In the method for producing an acylated product of alcohol according to the present invention, a carboxylic acid is used as an acylating agent. In the method for producing an acylated product of alcohol according to the present invention, since the above catalyst is used, a carboxylic acid which is inexpensive and does not require complicated post-treatment can be used as an acylating agent. Examples of the carboxylic acid include aliphatic carboxylic acids having about 1 to 20 carbon atoms (preferably 1 to 10) such as acetic acid, propionic acid, oleic acid, and palmitic acid; carbons such as benzoic acid and p-methylbenzoic acid. An aromatic carboxylic acid having a number of about 7 to 30 (preferably 7 to 18) can be mentioned. These can be used alone or in combination of two or more.

  As usage-amount of carboxylic acid, it is about 0.1-100 mmol with respect to 1 mmol of alcohol, Preferably it is 0.5-80 mmol, Most preferably, it is 1-50 mmol. Generally, as an acylating agent, it is known to use a carboxylic acid anhydride (for example, acetic anhydride, etc.) in addition to a carboxylic acid. However, the carboxylic acid anhydride is expensive compared to the carboxylic acid, and furthermore, there is a problem that the treatment of the excess carboxylic acid anhydride remaining after the reaction is complicated. Therefore, in this invention, it is preferable that the usage-amount of a carboxylic acid anhydride is about 20 mol% or less of the total amount of acylating agents, Preferably it is 10 mol% or less, Most preferably, it is 5 mol% or less.

  The amount of the catalyst used is, for example, about 5 to 100 mg, preferably 10 to 90 mg, particularly preferably 30 to 70 mg per 1 mmol of glycerol.

  Moreover, it is preferable to perform reaction of the said alcohol and carboxylic acid in presence of a solvent. This is because if the reaction is carried out in the absence of a solvent, the alcohol serving as the substrate is adsorbed on the catalyst and becomes lumpy and the progress of the reaction may be inhibited. Examples of the solvent include saturated or unsaturated hydrocarbon solvents such as pentane, hexane, heptane, octane and petroleum ether; aromatic hydrocarbon solvents such as benzene, toluene and xylene; methylene chloride, chloroform, 1,2- Halogenated hydrocarbon solvents such as dichloroethane, chlorobenzene, bromobenzene; ether solvents such as diethyl ether, diisopropyl ether, dibutyl ether, tetrahydrofuran (THF), dioxane, 1,2-dimethoxyethane, cyclopentyl methyl ether; acetamide, dimethyl Examples include amides such as acetamide, dimethylformamide, diethylformamide, and N-methylpyrrolidone; esters such as ethyl acetate, propyl acetate, and butyl acetate. These can be used individually by 1 type or in combination of 2 or more types.

  As the solvent of the present invention, among them, use of a solvent having low water solubility such as aromatic hydrocarbon solvent (particularly toluene) such as benzene, toluene, xylene, etc. It is preferable in that the reaction can be performed while removing, and the progress of the reaction can be promoted. The amount of the solvent used is, for example, in the range where the initial concentration of glycerol is about 0.05 to 10 mmol / mL when the reaction is carried out batchwise.

  The reaction temperature of the alcohol and carboxylic acid is, for example, about 70 to 200 ° C, preferably 80 to 200 ° C, particularly preferably 80 to 190 ° C. The reaction time is, for example, about 1 to 36 hours, preferably 1 to 24 hours, particularly preferably 3 to 24 hours.

  In the method for producing an acylated product of alcohol according to the present invention, the selectivity of the acylated product of alcohol can be improved by adjusting the reaction temperature and reaction time within the above ranges. Is a dihydric or higher alcohol, a selectivity of at least one selected from acylated forms of two or more alcohols is 70% or more (preferably 80% or more, particularly preferably 90% or more, most preferably 95% or more).

  For example, when glycerol is used as the alcohol, monoacylglycerol, diacylglycerol, and / or triacylglycerol can be obtained as the acylated product. Then, by adjusting the reaction temperature and reaction time, one kind selected from monoacylglycerol, diacylglycerol, and triacylglycerol can be produced with excellent selectivity.

For example, when the reaction temperature and reaction time are adjusted to the following ranges, monoacylglycerol can be produced with a selectivity of 70% or more (preferably 80% or more, particularly preferably 90% or more, most preferably 95% or more). . Monoacylglycerol includes 1-acylglycerol and 2-acylglycerol.
Reaction temperature: 60 to 200 ° C. (preferably 80 to 200 ° C., particularly preferably 80 to 140 ° C., most preferably 80 ° C. or more and less than 120 ° C.)
Reaction time: 1 to 36 hours (preferably 1 to 24 hours, particularly preferably 5 to 20 hours)

When the reaction temperature and reaction time are adjusted to the following ranges, diacylglycerol can be produced with a selectivity of 70% or more (preferably 80% or more, particularly preferably 95% or more). Diacylglycerol includes 1,2-diacylglycerol and 1,3-diacylglycerol.
Reaction temperature: 80 to 160 ° C. (preferably 100 to 140 ° C., particularly preferably 120 to 140 ° C.)
Reaction time: 1 to 36 hours (preferably 10 to 36 hours, particularly preferably more than 20 hours and 30 hours or less)

Furthermore, when the reaction temperature and reaction time are adjusted to the following ranges, triacylglycerol can be produced with a selectivity of 70% or more (preferably 75% or more, particularly preferably 90% or more, most preferably 95% or more). .
Reaction temperature: 80 to 200 ° C. (preferably 100 to 200 ° C., particularly preferably more than 140 ° C. and 200 ° C. or less)
Reaction time: 1 to 36 hours (preferably 1 to 24 hours, particularly preferably more than 2 hours and 24 hours or less, most preferably more than 4 hours and 24 hours or less)

  The reaction between the alcohol and the carboxylic acid can be carried out by arbitrarily selecting a batch mode, a semi-batch mode, a continuous flow mode, or the like. In addition, when it is desired to increase the amount of the acylated product of alcohol obtained from a predetermined amount of alcohol, it is preferable to employ a process in which unreacted alcohol after acylation is separated and recovered and recycled. If the said recycling process is employ | adopted, the production amount of the acylated product of alcohol when a predetermined amount of alcohol is used can be raised.

  After completion of the reaction, the reaction product can be separated and purified by, for example, separation means such as filtration, concentration, distillation, extraction and the like, or a separation means combining these.

  In the method for producing an acylated product of alcohol according to the present invention, an acylated product of alcohol can be efficiently produced by acylating the alcohol with an excellent conversion rate. The conversion rate of the alcohol is, for example, 60% or more, preferably 80% or more, particularly preferably 90% or more, and most preferably 95% or more.

  The catalyst of the present invention can maintain high catalytic activity and high selectivity even after repeated use-regeneration for about 5 times. The catalyst used in the reaction can be easily recovered from the reaction solution by physical separation techniques such as filtration and centrifugation, and the recovered catalyst is left as it is or subjected to washing, drying, and / or calcination treatment. And then reused. The washing treatment can be performed by a method of washing several times (for example, 2 to 3 times) with an appropriate solvent (for example, methanol). Therefore, an expensive catalyst can be repeatedly used, and the manufacturing cost can be greatly reduced.

  EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not limited by these Examples.

Preparation Example 1 (Preparation of catalyst (La (III) -mont))
The catalyst was prepared by an impregnation method. That is, 1.93 g (3.3 mmol) of La (OTf) ₃ (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 100 mL of distilled water, and Na-type montmorillonite (trade name “Kunipia F”, Kunimine Industries, Ltd.) was dissolved. And the mixture was stirred at 50 ° C. for 24 hours. The resulting precipitate was filtered with suction, washed with deionized water (1 L), filtered, and dried for 12 hours with a 110 ° C. dryer to obtain a dark white powder. Elemental analysis of the obtained powder revealed that it contained 6.06% by weight of lanthanum (III) ions.

Preparation Example 2 (Preparation of catalyst (Fe (III) -mont))
Instead of la (OTf) ₃ (manufactured by Wako Pure Chemical Industries, Ltd.), iron nitrate nonahydrate _{(Fe (NO 3) 3 ·} 9 (H 2 O)) (3.3mmol, 1.33g, sum A catalyst (Fe (III) -mont) (Fe (III) ion: 3 wt% contained) was obtained in the same manner as in Preparation Example 1, except that Kogyo Pharmaceutical Co., Ltd. was used.

Preparation Example 3 (Preparation of catalyst (Fe (II) -mont))
Instead of La (OTf) ₃ (manufactured by Wako Pure Chemical Industries, Ltd.), iron trifluoromethanesulfonate (Fe (OTf) ₂ ) (3.3 mmol, 1.17 g, manufactured by Wako Pure Chemical Industries, Ltd.) A catalyst (Fe (II) -mont) (containing Fe (II) ions: 3% by weight) was obtained in the same manner as in Preparation Example 1, except that it was used.

Preparation Example 4 (Preparation of catalyst (Cu (II) -mont))
Instead of La (OTf) ₃ (manufactured by Wako Pure Chemical Industries, Ltd.), copper trifluoromethanesulfonate (Cu (OTf) ₂ ) (3.3 mmol, 1.20 g, manufactured by Wako Pure Chemical Industries, Ltd.) A catalyst (Cu (II) -mont) (containing Cu (II) ion: 3.2% by weight) was obtained in the same manner as in Preparation Example 1 except that it was used.

Preparation Example 5 (Preparation of catalyst (In (III) -mont))
Instead of La (OTf) ₃ (manufactured by Wako Pure Chemical Industries, Ltd.), indium trifluoromethanesulfonate (In (OTf) ₃ ) (3.3 mmol, 1.85 g, manufactured by Wako Pure Chemical Industries, Ltd.) was used. A catalyst (In (III) -mont) (containing In (III) ions: 6% by weight) was obtained in the same manner as in Preparation Example 1, except that it was used.

Preparation Example 6 (Preparation of catalyst (Yb (III) -mont))
Instead of La (OTf) ₃ (manufactured by Wako Pure Chemical Industries, Ltd.), ytterbium trifluoromethanesulfonate (Yb (OTf) ₃ ) (3.3 mmol, 2.05 g, manufactured by Wako Pure Chemical Industries, Ltd.) A catalyst (Yb (III) -mont) (containing 6% by weight of Yb (III) ions) was obtained in the same manner as in Preparation Example 1 except that it was used.

Example 1
In a 15 mL glass high pressure tube (trade name “ACE high pressure tube”, manufactured by ACE GLASS), 50 mg of the catalyst (La (III) -mont) obtained in Preparation Example 1 and 1.0 mmol (0.092 g) of glycerol. ), 0.1 mL (1.8 mmol) of acetic acid and toluene (3 mL) were added, and the product was obtained by stirring at 100 ° C. for 10 hours in an air atmosphere (1 atm). In addition, the gas chromatograph mass spectrometer (GC-MS) was used for the measurement of a conversion rate, a selectivity, and a yield.

Examples 2-9, Comparative Examples 1-8
Example 1 was used except that the catalyst described in Table 1 below was used instead of the catalyst (1) obtained in Preparation Example 1, and the reaction time, reaction temperature, and reactor were changed as described in Table 1 below. The product was obtained in the same way. In Comparative Examples 1 and 2, the catalyst obtained in Preparation Example 2, in Comparative Examples 3 and 4, the catalyst obtained in Preparation Example 3, and in Comparative Example 5 KSF (trade name “montmorillonite KSF”, manufactured by Alfa Aesar) In Comparative Example 6, the catalyst obtained in Preparation Example 4 was used. In Comparative Example 7, the catalyst obtained in Preparation Example 5 was used. In Comparative Example 8, the catalyst obtained in Preparation Example 6 was used.

※
Ｇｌｙ：グリセロール
ＭＡＧ：モノアセチルグリセロール
ＤＡＧ：ジアセチルグリセロール
ＴＡＧ：トリアセチルグリセロール
ＲＴ：室温（２７℃）
ＰＴ：１５ｍＬのガラス製高耐圧管（商品名「エース高耐圧チューブ」、ACE GLASS社製）
ＡＣ：テフロン（登録商標）製内筒を入れた５０ｍＬのステンレス製オートクレーブ

*
Gly: glycerol MAG: monoacetylglycerol DAG: diacetylglycerol TAG: triacetylglycerol RT: room temperature (27 ° C.)
PT: 15 mL glass high pressure tube (trade name “ACE high pressure tube”, manufactured by ACE GLASS)
AC: 50 mL stainless steel autoclave with Teflon (registered trademark) inner cylinder

Claims (5)

A catalyst used in a reaction for reacting an alcohol with a carboxylic acid to obtain an acylated product of the alcohol , wherein 4 to 10% by weight of lanthanum (III) ions are immobilized between montmorillonite crystal layers based on the total amount of the catalyst. Catalyst for acylation of alcohol. The catalyst for acylating an alcohol according to claim 1, wherein the alcohol is glycerol .   A method for producing an acylated product of alcohol, wherein an acylated product of alcohol is obtained by reacting the alcohol with a carboxylic acid in the presence of the catalyst for acylating alcohol according to claim 1 or 2.   The method for producing an acylated product of an alcohol according to claim 3, wherein the reaction temperature is adjusted to 70 to 200 ° C and the reaction time is adjusted to a range of 1 to 36 hours.   The method for producing an acylated product of an alcohol according to claim 3 or 4, wherein the reaction is carried out in the presence of an aromatic hydrocarbon solvent.