JP2014062073A - Method for producing sugar carboxylate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing sugar carboxylate, wherein sugar carboxylate of any average degree of esterification can be obtained in high yield even if a solvent incompatible with water is used.SOLUTION: Provided is a method for producing sugar carboxylate of any average degree of esterification by reacting sugar with an acylating agent, wherein sugar, an acylating agent, water, and a water-immiscible solvent are contacted with each other in a reaction system within the respective predetermined limits of a content ratio, wherein, in the reaction system, the content ratio of the acylating agent is 0.1-35 wt.%, the content ratio of water is 30-99 wt.%, and the content ratio of the water-immiscible solvent is 0.5-50 wt.%, and wherein the content ratio of sugar in the reaction system is a ratio which is determined as an equivalent to the acylating agent and corresponds to a desired average degree of esterification.

Description

  The present invention relates to a method for producing a sugar carboxylic acid ester capable of obtaining a sugar carboxylic acid ester having an arbitrary degree of esterification in a high yield.

  Sugar carboxylic acid ester is a useful compound used in various industrial fields, and it has molding processability and physical properties such as amorphous resin such as ABS resin, polyvinyl chloride resin, epoxy resin and unsaturated polyester resin. It is known to improve or improve the flexibility and impact resistance of the crystalline polyester resin. The sugar carboxylic acid ester can be obtained by performing a predetermined purification step after the esterification reaction of sugar with an aliphatic or aromatic carboxylic acid, and further removing the solvent used for the reaction / purification. .

  However, when the esterification reaction is performed using a solvent that is incompatible with water, such as toluene, there is a problem that only an ester body having a high average degree of esterification can be obtained. For example, in the production of sucrose benzoate using toluene and water, the average degree of esterification of the obtained sucrose benzoate was 6.5 to 8 (Patent Document 1). On the other hand, when an esterification reaction is performed using a solvent compatible with water such as acetone, sucrose benzoate having a low substitution to a high substitution can be obtained (Patent Document 2). In the process of isolating the target product, it is difficult to separate the solvent used from the water, which causes a problem in terms of wastewater treatment load and recovery / reuse of the solvent. . For this reason, sugar carboxylic acid esters having an arbitrary degree of esterification (for example, an average degree of esterification of 4.0 to 6) using a solvent (water-immiscible solvent) that is easy to separate from water and incompatible with water. Less than .5 sucrose carboxylic esters).

Japanese Patent Publication No. 40-5688 JP 52-95625 A

  The present invention is intended to provide a method for producing a sugar carboxylate that can obtain a sugar carboxylate having an average degree of esterification in a high yield even when using a solvent that is incompatible with water. .

  As a result of diligent research aimed at solving the above problems, the present inventors have determined that the sugar, the acylating agent, water and the water-immiscible solvent have a content ratio within a predetermined range in the reaction system. It was found that a sugar carboxylic acid ester having any average degree of esterification can be obtained in a high yield by bringing it into contact with each other while maintaining the above, and further studies were completed to complete the present invention.

That is, the present invention is a method for producing a sugar carboxylate having an average degree of esterification by reacting a sugar with an acylating agent,
A sugar, an acylating agent, water and a water-immiscible solvent are contacted in the reaction system at a content ratio within a predetermined range;
The content of the acylating agent in the reaction system is 0.1 to 35% by weight, the content of water is 30 to 99% by weight, and the content of the water-immiscible solvent is 0.5 to 50% by weight. And the sugar content in the reaction system is a ratio determined as an equivalent to the acylating agent corresponding to the desired average degree of esterification.

The reaction is
It is carried out in a reaction apparatus comprising raw material supply means for continuously supplying raw materials and product recovery means for continuously recovering a reaction mixture containing a sugar carboxylic acid ester as a product after the reaction. Is preferred.

  The reaction is preferably carried out in the presence of a water-soluble catalyst.

  The sugar is preferably sucrose.

  The acylating agent is preferably a carboxylic acid chloride.

  The reactor is preferably equipped with a stirring mechanism.

  The arbitrary average esterification degree is preferably an arbitrary average esterification degree in the range of the average esterification degree of 4.0 or more.

  The present invention also relates to a sugar carboxylic acid ester produced by the sugar carboxylic acid ester production method and having an average degree of esterification within a range of 4.0 or more.

  According to the method for producing a sugar carboxylate of the present invention, a sugar carboxylate having an average degree of esterification can be produced in a high yield. In addition, since the production method uses water and a water-immiscible solvent as a solvent, it is easy to separate the water-immiscible solvent from water in the process of isolating the target product. Therefore, the production method of the present invention is very advantageous in terms of load on wastewater treatment and recovery / reuse of solvent, and is industrially very excellent.

  Further, in the production method of the present invention, the raw material supply means for continuously supplying the raw material for the esterification reaction, and the product recovery for continuously recovering the reaction mixture containing the sugar carboxylic acid ester as the product after the reaction When the reaction is carried out in a reaction apparatus configured with means, the sugar carboxylic acid ester as the target product can be obtained continuously and efficiently.

1 is a continuous horizontal reactor equipped with raw material supply means and product recovery means, which is an embodiment of a reaction apparatus for carrying out the esterification reaction of the present invention. It is a circulation type static mixer packed tube provided with a raw material supply means and a product recovery means, which is an embodiment of a reaction apparatus for carrying out the esterification reaction of the present invention. It is a continuous vertical reaction tank provided with a raw material supply means and a product recovery means, which is an embodiment of a reaction apparatus for carrying out the esterification reaction of the present invention. 1 is a continuous tubular reactor equipped with raw material supply means and product recovery means, which is an embodiment of a reaction apparatus for carrying out the esterification reaction of the present invention.

  Each element constituting the present invention will be described below.

(Object)
In the present invention, a sugar carboxylate refers to a compound obtained by reacting a sugar with an acylating agent.

  Here, the sugar is a monosaccharide such as glucose and galactose, sucrose (sucrose), trehalose, isotrehalose, neotrehalose, galactosucrose, disaccharides such as maltitol and lactitol, trisaccharide such as raffinose, or α -Oligosaccharides such as cyclodextrin, β-cyclodextrin, γ-cyclodextrin and the like. Among these, examples of preferable sugars include, for example, glucose, sucrose, and maltitol.

  One kind or two or more kinds of sugars can be used.

  An acylating agent refers to a carboxylic acid compound or a reactive derivative thereof. Here, the carboxylic acid compound means a compound having at least one carboxyl group in the molecule, and examples thereof include aromatic carboxylic acid and aliphatic carboxylic acid. Of these, monocarboxylic acids having one carboxyl group are preferred.

（式中、Ｒ¹〜Ｒ⁵は、独立に、水素原子、アルキル基およびアルコキシ基からなる群から選択される基である。）
で示される芳香族モノカルボン酸が挙げられる。 As an aromatic monocarboxylic acid, for example,
Formula (I)

(In the formula, R ^{1 to} R ⁵ are groups independently selected from the group consisting of a hydrogen atom, an alkyl group and an alkoxy group.)
The aromatic monocarboxylic acid shown by these is mentioned.

Here, each of R ^{1 to} R ⁵ is preferably independently a hydrogen atom or an alkyl group, and benzoic acid or one of them (preferably R ³ ), all of which are hydrogen atoms, is an alkyl group and the rest What is a hydrogen atom is more preferable.

Examples of the aliphatic monocarboxylic acid include
Formula (II)

R ⁶ —COOH (II)

(In the formula, R ⁶ is a group selected from the group consisting of a hydrogen atom, an alkyl group and an alkoxy group.)
The aliphatic monocarboxylic acid shown by these is mentioned.

Here, R ⁶ is preferably a hydrogen atom or an alkyl group.

  In the present specification, examples of the alkyl group include those having 1 to 20 carbon atoms, and among these, those having 1 to 5 carbon atoms are preferable, and more preferably a methyl group, an ethyl group, a propyl group, or an isopropyl group. is there. Examples of the alkoxy group include those having 1 to 20 carbon atoms, and among these, those having 1 to 5 carbon atoms are preferable, and a methoxy group, an ethoxy group, a propyloxy group, or an isopropyloxy group is more preferable.

  Examples of reactive derivatives of carboxylic acid compounds include the corresponding acid halides and acid anhydrides. Among these, acid halides (fluoride, chloride, bromide or iodide), among them, acid chlorides preferable.

  One or more acylating agents can be used.

  In the sugar carboxylic acid ester according to the present invention, the average degree of esterification means the average value of the number of esterified alcohols in one molecule of sugar. When the degree of esterification is low, the number of hydroxy groups, which are hydrophilic groups, increases, so the proportion of sugar carboxylic acid ester present in the aqueous phase increases, and the sugar carboxylic acid ester is mixed with the water-immiscible solvent phase ( In the present invention, the average degree of esterification is preferably not less than a predetermined value, and as such a value, for example, 4.0. On the other hand, there is no particular limitation on the upper limit of the average degree of esterification. For example, when the sugar is sucrose, the average degree of esterification is preferably 4.0 to 7.9. If it exceeds 7.9, industrial production tends to be difficult. As described above, the production method of the present invention is also useful for the production of sucrose benzoate having an average degree of esterification of less than 6.5, which is difficult to produce by the method of Patent Document 1.

(Ester synthesis)
In the esterification reaction of the present invention, the sugar, acylating agent, water and water-immiscible solvent among the above-mentioned reaction raw materials are contacted in the reaction system in a conventional manner under a content ratio within a predetermined range. Can be implemented.

  In the present invention, the solvent used for the esterification reaction is a mixed solvent of water and a water-immiscible solvent. Here, the water-immiscible solvent is a solvent that is not miscible with water at least to the extent that it is practically used, or is not miscible with water at all and has a low compatibility with water, and is used for the esterification reaction. It is a solvent that can dissolve the resulting sugar carboxylate. Examples of such solvents include aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, and chlorobenzene, chlorinated aliphatic hydrocarbons such as methylene dichloride, chloroform, carbon tetrachloride, and tetrachloroethylene, diethyl ether, and diisopropyl ether. And the like (herein, “lower” means, for example, that one alkyl group has 1 to 4 carbon atoms).

  These water-immiscible solvents can be used alone or in combination of two or more.

  The water content in the reaction system is 30 to 99% by weight. If it is less than 30% by weight, a highly substituted product tends to be preferentially produced, the average degree of esterification increases as the reaction proceeds, and only a highly substituted product tends to be easily obtained under high yield conditions. is there. On the other hand, if it exceeds 99% by weight, the concentration of the sugar carboxylic acid ester to be produced becomes extremely low, and the productivity tends to be remarkably lowered. The lower limit of the water content is preferably 70% by weight or more.

  The content of the acylating agent in the reaction system is 0.1 to 35% by weight. If it is less than 0.1% by weight, the sugar content must also be reduced to a degree corresponding to the desired average degree of esterification, so the concentration of the sugar carboxylic acid ester produced tends to decrease and the productivity tends to decrease significantly. is there. On the other hand, if it exceeds 35% by weight, the content of water is relatively lowered, and thus there is a tendency similar to the above.

  The content of the water-immiscible solvent in the reaction system is 0.5 to 50% by weight. If it is less than 0.5% by weight, the produced sugar carboxylic acid ester does not dissolve and tends to precipitate as an adhesive solid. On the other hand, if it exceeds 50% by weight, the content of water is relatively lowered, and thus there is a tendency similar to the above.

  The sugar content in the reaction system is an amount determined as an equivalent to the acylating agent corresponding to a desired average degree of esterification. The present invention has a feature that a sugar carboxylic acid ester of any corresponding average degree of esterification can be obtained by previously adjusting the sugar content in this way. A difference of about ± 0.5 may occur between the average degree of esterification calculated from the charged amount of the agent and the average degree of esterification of the target product actually obtained. This is because the reaction rate (yield) of the saccharide and the acylating agent is determined independently. The larger the difference between the reaction rates of the two, the greater the average esterification degree calculated from the charged amount and the actual yield. The difference between the average degree of esterification of the desired object is large.

  The reaction temperature is preferably 20 ° C. or lower. When it exceeds 20 ° C., the yield tends to decrease remarkably. The reaction temperature is preferably 0 ° C. or higher. If it is less than 0 degreeC, there exists a tendency for the water in a reaction system to coagulate easily.

  The reaction time is not particularly limited as long as it is longer than the time required for the esterification to proceed sufficiently. Different. On the other hand, it is needless to say that a reaction time as short as possible is more efficient as a production method. The reaction time under specific production conditions is shown in the Examples section. Under such circumstances, it is easy for those skilled in the art to find an appropriate reaction time for carrying out a specific esterification reaction.

  The esterification reaction of the present invention can be carried out in the presence of a catalyst. As such a catalyst, a base or an acid catalyst usually used for an esterification reaction can be similarly used. Examples of the base catalyst include basic compounds such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, ammonia, trimethylamine, and triethylamine. Examples of the acid catalyst include acidic compounds such as sulfuric acid and hydrogen chloride.

  When a catalyst is added, an appropriate amount of the catalyst content in the reaction system varies depending on conditions for carrying out the reaction, but a preferable range is, for example, 0.1 to 10% by weight. If the amount is less than 0.1% by weight, the reaction rate tends to be remarkably reduced. On the other hand, if it exceeds 10% by weight, a highly substituted product tends to be preferentially produced, and the average degree of esterification tends to increase.

  The catalyst can be used alone or in combination of two or more.

  In the esterification reaction of the present invention, the sugar, acylating agent, water and water-immiscible solvent among the above-mentioned reaction raw materials are contacted in the reaction system in a conventional manner under a content ratio within a predetermined range. Can be implemented. Therefore, for example, it can be carried out by mixing the reaction raw materials at once and, if desired, stirring. Alternatively, any of the reaction raw materials can be charged in a divided manner. For example, when a catalyst is used, the remaining catalyst is divided into three equal parts into a horizontal reaction tank in which only the entire amount of the other reaction raw materials and half of the catalyst are charged, and it is introduced from three places on the side of the reaction tank. it can.

  When an acid halide is used as the acylating agent, the side reaction of hydrolysis of the acylating agent is significant under strong alkalinity (for example, pH 13 or more depending on the reaction temperature, etc.). It is preferable to carry out at a degree.

  After the reaction, the reaction mixture is allowed to stand, and then the separated aqueous layer is removed to obtain a mixture of the sugar carboxylic acid ester and the solvent used for the ester synthesis. In addition, the mixture can be purified by further washing with water or other purification solvent one or more times, if desired. Examples of the solvent that can be used for such purification include organic solvents such as toluene, o-xylene, and m-xylene. These purification solvents can be used alone or in admixture of two or more.

(Reactor)
In the esterification reaction of the present invention, each reaction raw material is brought into contact under a content ratio within a predetermined range. Therefore, a raw material supply means for continuously supplying the raw material, and a sugar carboxylic acid as a product after the reaction It can implement suitably by using the reaction apparatus provided with the product collection | recovery means which collect | recovers the reaction mixture containing ester continuously. Use of such a reaction apparatus is also advantageous from the viewpoint that the product can be obtained continuously and efficiently.

  As the raw material supply means, each reaction raw material, or at least sugar, acylating agent, water and water-immiscible solvent among the respective reaction raw materials is continuously maintained so that the content ratio in the reaction system is within a predetermined range. Any means can be suitably used as long as it can be supplied to the tank. However, it is preferable to provide means capable of appropriately adjusting the supply amount of each raw material. As the product recovery means, any means can be suitably used as long as it can continuously recover the reaction mixture containing the sugar carboxylic acid ester as the product after the reaction. It is preferable to provide a means capable of separating water from the recovered reaction mixture. The reaction apparatus is not particularly limited as long as the esterification reaction from the supplied reaction raw material to the product can be suitably carried out, but from the viewpoint of allowing the esterification reaction to proceed efficiently, a stirring mechanism is provided. From the viewpoint of managing the reaction temperature within a predetermined range, it is preferable to include a device for monitoring (thermometer) and adjusting (cooling mechanism) the reaction temperature.

  Specific examples of the reaction apparatus in the present invention include the reaction apparatuses shown in FIGS.

  FIG. 1 shows a reaction apparatus 1 which is a horizontal reactor 13 provided with a stirring blade 11 with a motor (for example, a “cross-shaped stirring blade” for a stirring blade) and a temperature indicating controller 12, a sugar dissolving tank 21, Raw material supply means 2 comprising an aqueous sugar solution tank 22, a catalyst tank 23, an acylating agent tank 24, a water-immiscible solvent tank 25, a pump 26, a control valve 27, and a flow rate indicating controller 28; The reaction apparatus which consists of the product collection means 3 provided with the separation tank 31 and the tank 32 for sugar carboxylate ester is represented.

  In the reaction apparatus, the raw sugar is dissolved in the sugar dissolution tank 21 and converted into a sugar aqueous solution in the sugar aqueous solution tank. Each raw material of “aqueous sugar solution”, “catalyst”, “acylating agent” and “water-immiscible solvent” is first mixed with “aqueous sugar solution” and “catalyst” and “acylating agent” and “water” After the “immiscible solvent” is mixed, both the mixed liquids are combined and then supplied to the reaction apparatus. The supply speed of each raw material is adjusted to an appropriate speed by a pump 26 and a control valve 27 while being monitored by a flow rate indicating controller 28. In addition, when a catalyst is solid, it melt | dissolves in water beforehand and is made into a liquid. Alternatively, even if the catalyst is liquid, it is diluted with water in advance to obtain a liquid in order to adjust the concentration or viscosity.

  The esterification reaction proceeds in the reactor 1 by the raw material thus supplied. In FIG. 1, since the stirring blade 11 provided with the motor is equipped, the reaction proceeds efficiently. The reaction temperature can be monitored by the temperature indicating controller 12. The reaction apparatus can be managed such that the reaction liquid maintains a predetermined temperature by circulating cooling water around it.

  The reaction mixture after completion of the reaction is recovered by the product recovery means 3. The recovered reaction mixture is separated into an aqueous layer and an oil layer by an ordinary method in an oil / water separation tank 31 to remove water and impurities contained in the water, and then recovered in the sugar carboxylate ester tank 32. After purification as required, a sugar carboxylic acid ester is obtained by distilling off the solvent.

  FIG. 2 is a reaction apparatus in which the reaction apparatus 1 in FIG. 1 is a static mixer filling tube 17 including a temperature indicating controller 12, a reaction mixture tank 14, a three-way valve 15, and a water bath 16. In the reaction apparatus, a static mixer is filled as a stirring mechanism, and the raw material compound as a fluid can be efficiently stirred and mixed. In addition, since the reaction apparatus is provided with a three-way valve, the reaction mixture that has passed through the static mixer filling pipe 17 is led to the reaction mixture tank 14 to be passed through the static mixer filling pipe 17 again. The esterification reaction can be repeated. The water bath 16 is useful for controlling the reaction temperature within a predetermined range. The role of the temperature indicating controller 12 is as described above.

  FIG. 3 is a reaction apparatus in which the reaction apparatus 1 in FIG. 1 is a continuous stirring tank 19 having a temperature indicating controller 12 and a motor-equipped mixer 18. The motor-equipped mixer 18 (specifically, a homomixer or the like) functions as a stirring mechanism. The role of the temperature indicating controller 12 is as described above.

  4 is a reaction apparatus in which the reaction apparatus 1 in FIG. 1 is a tubular reactor 111 having a temperature indicating controller 12 and a water bath 16. The roles of the temperature indicating controller 12 and the water bath 16 are as described above.

  On the other hand, the esterification reaction of the present invention can also be suitably carried out by subjecting it to a batch-type reaction. Examples of such a reaction apparatus include a stirring tank and various circulation reaction apparatuses.

(Resin modifier)
The sugar carboxylate according to the present invention is useful as a resin modifier and improves the molding processability and physical properties of amorphous resins such as ABS resin, polyvinyl chloride resin, epoxy resin, and unsaturated polyester resin. It is useful for improving the flexibility and impact resistance of the crystalline polyester.

  The ABS resin is not particularly limited. For example, polybutadiene, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, chlorinated polyethylene, acrylic rubber (for example, methyl acrylate, ethyl acrylate, Butyl acrylate, etc.) and acrylonitrile, styrene, acrylic acid, acrylic acid amide, 2-chloroethyl vinyl ether, and other rubbery polymers such as acrylonitrile, styrene, α-methylstyrene, methacrylic acid Examples thereof include those obtained by graft polymerization of methyl and the like, and further include acrylonitrile-polybutadiene-styrene graft copolymers. ABS resin may be used individually by 1 type, and may use 2 or more types together.

  The polyvinyl chloride resin is not particularly limited, and for example, vinyl chloride homopolymer resin, chlorinated vinyl chloride resin, one or more monomers copolymerizable with vinyl chloride monomer, A vinyl chloride copolymer resin (for example, vinyl acetate-vinyl chloride copolymer, ethylene-vinyl chloride copolymer, etc.) obtained by random copolymerization or block copolymerization, or a functional group such as a hydroxyl group is grafted to the above resin. And a resin obtained by reacting such a functional group with a reactive compound and graft-bonding them. A polyvinyl chloride resin may be used individually by 1 type, and may use 2 or more types together.

  The epoxy resin is not particularly limited. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, alkylphenol novolac type epoxy resin, phenol biphenyl aralkyl epoxy resin. Aralkyl type epoxy resins, biphenol type epoxy resins, naphthalene type epoxy resins, dicyclopentadiene type epoxy resins, biphenyl type epoxy resins, anthracene type epoxy resins, condensates of phenols and aromatic aldehydes having phenolic hydroxyl groups Examples include epoxidized products, triglycidyl isocyanurate, and alicyclic epoxy resins. An epoxy resin may be used individually by 1 type, and may use 2 or more types together.

  The unsaturated polyester resin is not particularly limited. For example, the unsaturated polyester resin is synthesized by addition reaction or dehydration condensation reaction of α, β-olefinic unsaturated dicarboxylic acid or its anhydride and glycol. Further, saturated dicarboxylic acids, aromatic dicarboxylic acids or anhydrides thereof, or dicyclopentadiene that reacts with carboxylic acids can be used in combination. Examples of the α, β-olefin unsaturated dicarboxylic acid include maleic acid, fumaric acid, itaconic acid, citraconic acid and anhydrides of these dicarboxylic acids. Examples of dicarboxylic acids used in combination with these α, β-olefinic unsaturated dicarboxylic acids include, for example, adipic acid, sebacic acid, succinic acid, phthalic anhydride, orthophthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid And tetrachlorophthalic acid. Among these, it is preferable to use fumaric acid as the α, β-olefinic unsaturated dicarboxylic acid and isophthalic acid as the dicarboxylic acid. An unsaturated polyester resin may be used individually by 1 type, and may use 2 or more types together.

  The crystalline polyester resin is not particularly limited. For example, polyethylene terephthalate, poly-1,4-butylene terephthalate, polyethylene-2,6-naphthalate, polycyclohexanedimethanol terephthalate, poly-1,4-butylene. Examples thereof include crystalline polyesters such as diphenyl-4,4′-dicarboxylate, polyethyleneoxybenzoate, poly-1,3-propylene terephthalate, poly-1,6-hexylene terephthalate, and among these, polyethylene terephthalate, poly- 1,4-butylene terephthalate and polyethylene-2,6-nanophthalate are preferred. A crystalline polyester resin may be used individually by 1 type, and may use 2 or more types together.

  In addition, various additives, such as an impact strength modifier, a stabilizer, a lubricant, a filler, a pigment, a foaming agent, and an ultraviolet stabilizer, can be added to these resins as necessary.

  When the sugar carboxylic acid ester of the present invention is used as a resin modifier, the blending ratio to the resin is preferably 1 to 40 parts, more preferably 1 to 30 parts, relative to 100 parts of the resin. If the amount is less than 1 part, the intended performance tends not to be obtained, and if it exceeds 40 parts, the possibility of bleeding out due to long-term storage or the like increases.

In the present specification, the term “parts” simply means “parts by weight”. The “average esterification degree” in the sugar carboxylate is a value determined by proton nuclear magnetic resonance ( ¹ H-NMR).

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

(Raw materials used)
Sugar (1): Sucrose (manufactured by Nacalai Tesque)
Sugar (2): D-(+)-glucose (manufactured by Nacalai Tesque)
Acylating agent (1): Benzoyl chloride (manufactured by Nacalai Tesque)
Acylating agent (2): Benzoic acid (manufactured by Nacalai Tesque)
Water-immiscible solvent (1): Toluene (manufactured by Nacalai Tesque)
Water-immiscible solvent (2): diethyl ether (manufactured by Nacalai Tesque)
Catalyst (1): Sodium hydroxide (manufactured by Nacalai Tesque)
Catalyst (2): sulfuric acid (manufactured by Nacalai Tesque)

(Reactor used)
Reactor (1): Continuous horizontal reactor of FIG. 1 (stirring mechanism: stirring mechanism (1) (cross stirrer blade))
Reactor (2): Circulating static mixer filling tube of FIG. 2 (stirring mechanism: stirring mechanism (2) (static mixer, manufactured by Noritake Company Limited)
Reactor (3): Continuous vertical reaction tank of FIG. 3 (stirring mechanism: stirring mechanism (3) (mixer: “continuous homomic line flow”, manufactured by Primix Corporation))
Reactor (4): Continuous tubular reactor of FIG. 4 (stirring mechanism: none)
Reactor (5): Batch type stirring tank (stirring mechanism: stirring mechanism (4) (anchor))
Reactor (6): Batch-type stirring tank (stirring mechanism: stirring mechanism (5) (mixer: “Homomixa Mark II”, manufactured by Primix Corporation)

Example 1
As shown in Table 1, each raw material was supplied to the reactor (1) to carry out an esterification reaction. That is, each raw material is supplied by the raw material supply means 2 of the reactor (1) so that the content in the reaction system is as shown in Table 1, and while passing through the reactor (1), Table 1 It was subjected to an esterification reaction under the reaction conditions described. Here, the reaction time is a time calculated as the time (residence time) from when each raw material flows into the reaction apparatus (1) at a predetermined inflow rate to when it flows out as a reaction mixture (particularly different). Unless otherwise noted, the same applies to the following continuous devices). The reaction mixture thus obtained was recovered by the product recovery means 3, and after removing the aqueous layer in the oil / water separation tank 31, it was recovered in the sugar carboxylate ester tank 32. The solvent was distilled off from the reaction mixture collected using a rotary evaporator to obtain sucrose benzoate as a target product. The results are shown in Table 1.

Examples 2-11
Corresponding raw material compounds were treated in the same manner as in Example 1 in accordance with the description in Table 1, to obtain sucrose benzoate as a target product. The results are shown in Table 1.

Example 12
The corresponding starting material compound was treated in the same manner as in Example 1 according to the description in Table 1 to obtain the objective sucrose benzoate. However, instead of the reactor (1), the reactor (2) (circulation type static mixer packed tube) was used as the reactor. In the reactor (2), when starting the circulation, the raw material supply was stopped. The number of recycles of the raw material supply was 17 times. Here, the reaction time is the time during which the raw material is stirred by the static mixer filling tube (17). The results are shown in Table 1.

Example 13
The corresponding starting material compound was treated in the same manner as in Example 1 according to the description in Table 1 to obtain the objective sucrose benzoate. However, the reaction apparatus (3) was used instead of the reaction apparatus (1). The results are shown in Table 1.

Example 14
The corresponding starting material compound was treated in the same manner as in Example 1 according to the description in Table 1 to obtain the objective sucrose benzoate. However, the reaction apparatus (4) was used instead of the reaction apparatus (1). The results are shown in Table 1.

Example 15
The raw material compounds shown in Table 1 were charged into an agitation tank (reaction apparatus (5)) equipped with an agitation mechanism using an anchor, and an esterification reaction was carried out under the conditions shown in Table 1. Then, it separated into the water layer and the oil layer by stationary separation, and the oil layer containing sucrose benzoate was obtained by removing the water layer. Toluene was distilled off from the oil layer using a rotary evaporator to obtain 327.2 g of sucrose benzoate as a target product. The results are shown in Table 1.

Example 16
The corresponding raw material compound was treated in the same manner as in Example 15 according to the description in Table 1 to obtain 71.4 g of the objective sucrose benzoate. However, instead of the reaction apparatus (5), the reaction apparatus was a reaction apparatus (6) (the stirring mechanism of the stirring tank was a mixer (Homomixer Mark II, manufactured by Primix Co., Ltd.)). The results are shown in Table 1.

Examples 17-19
Corresponding raw material compounds were treated in the same manner as in Example 1 in accordance with the description in Table 1, to obtain sucrose benzoate or glucose benzoate as target compounds, respectively. The results are shown in Table 1.

Comparative Examples 1 and 2
Corresponding raw material compounds were treated in the same manner as in Example 1 according to the description in Table 2 to obtain sucrose benzoate as the target product. The results are shown in Table 2.

  As described above, in Examples 1 to 19 of the present invention, by setting the content ratio of the predetermined raw material in the reaction system during the ester reaction within the predetermined range, the intended degree of esterification (equivalent ratio in the charged amount) Compared with the content ratio of water in the reaction system outside the prescribed range (23% by weight), while the sugar ester having a small esterification degree with a small difference from) was obtained in high yield In Examples 1 and 2, only those having a large difference from the intended degree of esterification and a low yield were obtained. As apparent from the comparison between Comparative Examples 1 and 2, when the reaction time was extended to increase the yield, the difference from the intended degree of esterification became larger.

  According to the present invention, a sugar carboxylate having an average degree of esterification can be produced in a high yield, and in addition, it is very advantageous in terms of wastewater treatment load and solvent recovery / reuse. Industrially excellent methods for producing sugar carboxylic acid esters can be provided.

DESCRIPTION OF SYMBOLS 1 Reaction apparatus 11 Stirring blade with motor 12 Temperature indicating controller 13 Horizontal reactor 14 Reaction mixture tank 15 Three-way valve 16 Water bath 17 Static mixer filling pipe 18 Motorized mixer 19 Continuous stirring tank 111 Tube reactor 2 Feeding of raw material Means 21 Sugar dissolution tank 22 Sugar aqueous solution tank 23 Catalyst solution tank 24 Acylating agent tank 25 Water immiscible solvent tank 26 Pump 27 Control valve 28 Flow rate indicating controller 29 Stirring blade 3 with motor Product recovery means 31 Oil / water separation tank 32 Sugar carboxylic acid ester tank

Claims (8)

A method for producing a sugar carboxylate having an average degree of esterification by reacting a sugar with an acylating agent,
A sugar, an acylating agent, water and a water-immiscible solvent are brought into contact with each other at a content ratio within a predetermined range in the reaction system,
The content of the acylating agent in the reaction system is 0.1 to 35% by weight, the content of water is 30 to 99% by weight, and the content of the water-immiscible solvent is 0.5 to 50% by weight. %, And the sugar content in the reaction system is a ratio determined as an equivalent to the acylating agent corresponding to the desired average degree of esterification. The reaction
It is carried out in a reaction apparatus comprising a raw material supply means for continuously supplying raw materials, and a product recovery means for continuously recovering a reaction mixture containing a sugar carboxylic acid ester as a product after the reaction. A process for producing a sugar carboxylate according to claim 1. The method for producing a sugar carboxylate according to claim 1 or 2, wherein the reaction is carried out in the presence of a water-soluble catalyst. The method for producing a sugar carboxylate according to any one of claims 1 to 3, wherein the sugar is sucrose. The method for producing a sugar carboxylic acid ester according to any one of claims 1 to 4, wherein the acylating agent is a carboxylic acid chloride. The method for producing a sugar carboxylate according to any one of claims 1 to 5, wherein the reaction apparatus comprises a stirring mechanism. The method for producing a sugar carboxylate according to any one of claims 1 to 6, wherein the arbitrary average esterification degree is an arbitrary average esterification degree in a range of an average esterification degree of 4.0 or more. A sugar carboxylate produced by the method for producing a sugar carboxylate according to claim 7, wherein the average degree of esterification is any value in the range of 4.0 or more.

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