JPH07184672A - Method for producing ester by enzyme - Google Patents

Abstract

(57) [Summary] [Structure] An acyl group donor composed of a carboxylic acid and / or a carboxylic acid ester and an acyl group acceptor composed of an alcohol or a substance having at least one hydroxyl group in the molecule are reacted in the presence of an enzyme. A method for producing an ester by an enzyme, characterized in that one of an acyl group donor and an acyl group acceptor is gradually added in a reaction process for producing a carboxylic acid ester. [Effect] When an ester is produced by an enzymatic reaction,
The ester can be efficiently produced with high purity without removing water and / or lower alcohol produced in the reaction process.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for efficiently producing an ester by an enzymatic reaction.

[0002]

BACKGROUND ART Synthesis of esters is a very useful reaction industrially, and is generally carried out using a chemical catalyst such as toluenesulfonic acid. The esters obtained by these methods often contain residual catalysts and by-products, and more treatments are required to obtain the target pure product, which requires complicated steps. For this reason, an ester production method using an enzyme, which is relatively easy to obtain, is desirable.

Although a method for producing an ester using an enzyme is a known technique, it generally has drawbacks such as low yield, high cost and complicated equipment. Regarding the cost and equipment, it is expected that the reaction will be significantly reduced and simplified by the continuous reaction using the column. Further, it has been observed that the yield is greatly improved by efficiently treating the water or lower alcohol produced as the reaction progresses.

The water or lower alcohol produced by the esterification reaction or transesterification reaction hinders these reactions, and in order to promote the reaction, a method of discharging them out of the system is generally adopted. ing. As a method for removing water or lower alcohol, a method using a dry gas (JP-A-2-142485), a decompression method (JP-A-3-198784), a method using a dehydrating agent (JP-A-1-120295), Many methods such as a method using a thin film (JP-A-1-101890) are disclosed. However, the removal of water or lower alcohol in the reaction process has problems that the reaction apparatus becomes complicated, cannot be used for continuous reaction using a column, or the reaction is stopped in some cases.

[0005]

DISCLOSURE OF THE INVENTION In the present invention, when an ester is produced by an enzymatic reaction, it is possible to adjust the concentration of these to an appropriate range for the enzymatic reaction without removing water and / or lower alcohol produced in the reaction process. It is an object of the present invention to provide a method for efficiently producing an ester by carrying out the reaction under conditions that can be maintained.

[0006]

Means for Solving the Problems As a result of intensive studies to achieve the above-mentioned object, the present inventors have found that in the esterification reaction or transesterification reaction with an enzyme, water and / or a lower alcohol produced by the reaction are reacted. The inventors have found that an ester can be efficiently produced by gradually adding one of an acyl group donor and an acyl group acceptor without removing it in the process, and completed the present invention.

That is, in the present invention, an acyl group donor composed of a carboxylic acid and / or a carboxylic acid ester and an acyl group acceptor composed of an alcohol or a substance having at least one hydroxyl group in the molecule are reacted in the presence of an enzyme. In the reaction process for producing a carboxylic acid ester, one of an acyl group donor and an acyl group acceptor is gradually added, which is a method for producing an ester by an enzyme.

The present invention will be described in detail below. The enzymatic reaction applicable to the present invention is carried out by reacting an acyl group donor consisting of a carboxylic acid and / or a carboxylic acid ester with an acyl group acceptor consisting of alcohol or a substance having at least one hydroxyl group in the molecule in the presence of an enzyme. There is no particular limitation as long as it is a reaction capable of producing a carboxylic acid ester, an esterification reaction in which a carboxylic acid and an alcohol are dehydrated and condensed, an ester in which an alcohol or the like is reacted with a carboxylic acid ester to exchange an alkoxyl group. Any of the exchange reactions may be used, and the esterification reaction and the transesterification reaction may be carried out simultaneously by reacting with a alcohol or the like using a mixture of carboxylic acid and carboxylic acid ester as an acyl group donor.

Water is produced by the esterification reaction, and a lower alcohol derived from a carboxylic acid ester which is an acyl group donor is produced by the transesterification reaction. If the esterification reaction and the transesterification reaction are carried out at the same time, water and the lower alcohol are obtained. Is generated. In the present invention, the desired ester is produced without the need to remove water and / or lower alcohol produced by the reaction in the reaction process.

The acyl group donor used in the present invention is usually a saturated or unsaturated, linear or branched C2 atom.
36 mono- or dicarboxylic acids, for example caproic acid,
Caprylic acid, capric acid, lauric acid, palmitic acid,
Stearic acid, behenic acid, oleic acid, linoleic acid, isostearic acid, sebacic acid, suberic acid, or esters of these carboxylic acids, for example, lower alkyl esters having 1 to 6 carbon atoms such as methyl, ethyl, propyl, etc. , Other carboxylic acids such as aromatic carboxylic acids, or esters thereof.

On the other hand, the acyl group acceptor is alcohol or a substance having at least one hydroxyl group in the molecule. The alcohol has 1 to 24 carbon atoms, may be saturated or unsaturated, and may be branched or linear. Further, it may be monovalent or polyvalent and includes grades 1 to 3. For example,
Examples thereof include ethanol, methanol, propanol, isopropanol, ethylene glycol, propylene glycol, glycerol, lauryl alcohol, myristyl alcohol, cetyl alcohol and polyethylene glycol. Further, even a substance not generally called an alcohol can be an acyl group acceptor as long as at least one hydroxyl group (alcoholic OH group) is present in the molecule. For example, sugars such as glucose, sorbitol and sucrose; and partial esters of alcohols and sugars such as monoglyceride and diglyceride are also included.

The enzyme used in the present invention is not particularly limited, but lipase is preferably used. Further, those enzymes may be of any origin such as plants, microorganisms, animals, etc., but it is generally preferable to use those derived from microorganisms. Preferred microorganisms include Rhizopus, Candida, Mucor, Pseudomonas, Aspergillus, and Humicola.

The enzyme may be used as it is, or may be immobilized on a hydrophobic material, an ion exchange resin or the like, but it is preferably immobilized and used because it can be reused. Usually, the enzyme preparation contains a small amount of water even if it is a dry enzyme, but depending on the substrate and the origin of the enzyme, this enzyme may be used after being moistened with water, and if necessary, separately at the beginning of the reaction. Water may be added. The esterification reaction and the transesterification reaction are reactions that generate water and a lower alcohol, respectively, and if they are not removed from the reaction system, they level off at a constant yield based on a certain equilibrium constant. The degree of esterification is improved by continuously removing water and lower alcohols. That is, in a method for producing an ester by an esterification reaction or a transesterification reaction, a treatment method for water or a lower alcohol is generally indispensable.

In the present invention, water and / or lower alcohol produced by the reaction need not be removed in the reaction process,
This is a method for efficiently producing an ester. That is, the method of the present invention is a method in which either an acyl group acceptor or an acyl group donor is gradually added. Generally, water is indispensable for the enzymatic reaction, but in the esterification and transesterification reactions, the reaction equilibrium is expected to increase the yield by removing water or lower alcohol produced from the system. However, the treatment methods of water or lower alcohols that have been reported so far are not methods that merely remove it continuously while maintaining an optimum amount for the enzyme. Therefore, depending on the mode of removing water or lower alcohol, there is a concern that the enzyme reaction may be inhibited or the enzyme may be inactivated.

In the present invention, the acyl group donor and the acyl group acceptor are not added at once to the reaction system, but one of them is gradually added to obtain the optimum water or lower alcohol concentration or conditions close thereto. This is a method for efficiently producing an ester by reacting under. The substrate to be gradually added may be an acyl group donor or an acyl group acceptor, but a substrate having water affinity is more preferable because it suppresses concentration of water concentration around the enzyme. An acyl group acceptor generally satisfies this property, and an acyl group donor having a low molecular weight, for example, an acyl group donor having a water solubility of a lower fatty acid having 2 to 4 carbon atoms also has this property. Furthermore, if a substrate that is easily removed in the purification step is used, the removed substrate can be reused as a substrate, which is economical.

The acyl group donor or the acyl group acceptor gradually added in the reaction process is continuously or intermittently added in two or more steps in consideration of the reaction rate of the reaction system. It is preferable. Although it depends on the type of enzyme and substrate, when it is added intermittently, it is more preferable to add it in 3 to 10 times. 3 from the start of the reaction of the acyl group donor or the acyl group acceptor gradually added in the reaction process
The total addition amount during the time period is preferably 0.5 mol or more with respect to 1 mol of the other acyl group acceptor or acyl group donor. The upper limit of the addition amount can be freely selected because it depends on the type of substrate used.

When the reaction is carried out using a column, an acyl group donor or an acyl group acceptor can be supplied in the middle of the column or from each inlet of the continuous column.

EXAMPLES The present invention will be described in more detail below with reference to examples and comparative examples, but the scope of the present invention is not limited to these examples. (Example 1) 190 g of propylene glycol (PG) and 710 g of oleic acid (OA) were mixed in equimolar amounts, 20 g of immobilized lipase (Lipozyme: manufactured by Novo, the same applies below) was added, and the reaction was started at 40 ° C. Sampling was performed at each time shown in Table 1, the esterification rate was measured by iatroscan, propylene glycol (PG) was added, and the reaction was continued while adjusting to each set molar ratio (PG / OA). The cumulative molar ratio (PG / OA) was adjusted to 10, and the addition of propylene glycol (PG) was completed. As a result, after 48 hours, an esterification rate of 95% and a monoester of 96% were achieved.

[0018]

[Table 1]

(Example 2) Propylene glycol (P
G) 38 g and caprylic acid (CA) 720 g were mixed [molar ratio (PG / CA) = 0.1], and immobilized lipase 40 g was added.
The reaction started at 40 ° C. 380g of propylene glycol (PG) is added every 3 hours, and the cumulative molar ratio (PG / CA)
Was set to 10, and the reaction was terminated. After 48 hours, the reaction solution was analyzed by Iatroscan, and an esterification rate of 92% and a monoester of 98% were achieved.

Example 3 92 g of glycerol (GL) and 280 g of oleic acid (OA) were mixed in equimolar amounts, and 2 g of water was added. 10 g of immobilized lipase was added and the reaction was started at 40 ° C. 92 g of glycerol (GL) was added every 3 hours, and the reaction was terminated by setting the cumulative molar ratio (GL / OA) to 10. After 48 hours, the esterification rate was 95%, and the ester was obtained as a monoglyceride with a purity of 98%.

Example 4 Isopropyl alcohol (I
PA) and myristic acid (MA) (230 g) were mixed in equimolar amounts, and water (6 g) was added. Add 10g of immobilized lipase
The reaction started at 40 ° C. 60 g of isopropyl alcohol (IPA) was added every 3 hours, and the cumulative molar ratio (IPA /
The reaction was terminated by setting MA) to 10. Esterification rate is 9
Reached 7.6%. Isopropyl alcohol was recovered from the reaction mixture by distillation and reused.

(Example 5) Propylene glycol (P
G) 38 g and ethyl stearate (ES) 156 g are mixed in an equimolar amount, water 5 g is added, and immobilized lipase 10 g is added.
The reaction started at 40 ° C. Set molar ratio (P
G / ES) is PG / OA described in Table 1 in Example 1.
Propylene glycol (P
G) was added and the reaction was continued. Cumulative molar ratio (PG / E
S) was made 10 and the addition of propylene glycol (PG) was completed. As a result, after 48 hours, an esterification rate of 92% was achieved.

Comparative Example 1 Propylene glycol (P
G) 1.9 kg and oleic acid (OA) 710 g were mixed [molar ratio (PG / OA) = 10], and immobilized lipase 20 g was added to give 40
When the reaction was carried out at ℃, the esterification ratio after 48 hours was 5
%Met.

[0024]

INDUSTRIAL APPLICABILITY According to the present invention, when an ester is produced by an enzymatic reaction, the ester can be efficiently produced with high purity without removing water and / or lower alcohol produced in the reaction process. . Further, it becomes possible to continuously produce by using a column or the like using an immobilized enzyme.

Claims (5)

[Claims] 1. A carboxylic acid ester by reacting an acyl group donor composed of a carboxylic acid and / or a carboxylic acid ester with an alcohol or an acyl group acceptor composed of a substance having at least one hydroxyl group in the molecule in the presence of an enzyme. A method for producing an ester by an enzyme, wherein one of an acyl group donor and an acyl group acceptor is gradually added in the reaction process for producing. 2. The production method according to claim 1, wherein the gradually added acyl group donor or acyl group acceptor has a water affinity. 3. The production method according to claim 1, wherein one of the acyl group donor and the acyl group acceptor is added continuously or in two or more times. 4. The method according to claim 1, wherein the acyl group donor is a mono- or dicarboxylic acid or an ester thereof. 5. The method according to claim 1, wherein the enzyme is lipase.