METHOD OF PRODUCING ALIPHATIC GLYCOSIDE COMPOUND OR SUGAR FATTY ACID ESTER COMPOUND

Abstract

Provided is a method of producing an aliphatic glycoside compound or a sugar fatty acid ester compound by subjecting an intramolecularly dehydrated sugar and an alcohol or carboxylic acid compound of an aliphatic hydrocarbon to an addition reaction in the presence of an acid catalyst.

Claims

1. A method of producing an aliphatic glycoside compound or a sugar fatty acid ester compound, which comprises a step of subjecting an intramolecularly dehydrated sugar and an alcohol or carboxylic acid compound of an aliphatic hydrocarbon to an addition reaction in the presence of an acid catalyst.

2. The method of producing an aliphatic glycoside compound or a sugar fatty acid ester compound according to claim 1, wherein the acid catalyst is a solid acid catalyst.

3. The method of producing an aliphatic glycoside compound or a sugar fatty acid ester compound according to claim 2, wherein the solid acid catalyst is a cation exchanger.

4. The method of producing an aliphatic glycoside compound or a sugar fatty acid ester compound according to claim 1, wherein the intramolecularly dehydrated sugar is an intramolecular dehydration reaction product in which water molecules are eliminated from two hydroxy groups including a hydroxy group bonded to a carbon atom at the 1-position in the cyclic structure.

5. The method of producing an aliphatic glycoside compound or a sugar fatty acid ester compound according to claim 1, wherein the intramolecularly dehydrated sugar is an intramolecularly dehydrated sugar of an aldose.

6. The method of producing an aliphatic glycoside compound or a sugar fatty acid ester compound according to claim 1, wherein the intramolecularly dehydrated sugar is levoglucosan.

7. The method of producing an aliphatic glycoside compound or a sugar fatty acid ester compound according to claim 1, wherein the number of carbon atoms constituting the alcohol or carboxylic acid compound is 1 to 22.

8. The method of producing an aliphatic glycoside compound or a sugar fatty acid ester compound according to claim 1, wherein the aliphatic hydrocarbon is a saturated aliphatic hydrocarbon.

9. The method of producing an aliphatic glycoside compound or a sugar fatty acid ester compound according to claim 1, wherein a mixture of the alcohol or carboxylic acid compound of an aliphatic hydrocarbon and the intramolecularly dehydrated sugar is brought into contact with the acid catalyst.

10. The method of producing an aliphatic glycoside compound or a sugar fatty acid ester compound according to claim 9, wherein the mixture is brought into contact with the acid catalyst by a batch method or a continuous method.

11. The method of producing an aliphatic glycoside compound or a sugar fatty acid ester compound according to claim 9, wherein the mixture is a mixed liquid obtained by dissolving at least a portion of the intramolecularly dehydrated sugar in the alcohol or carboxylic acid compound of an aliphatic hydrocarbon.

Description

EXAMPLES

[0074] Hereinafter, the present invention will be described in more detail based on Examples; however, the technical scope of the present invention is not intended to be limited in any way by these descriptions. Incidentally, unless particularly stated otherwise in the following Examples, general methods known to those ordinarily skilled in the art were followed.

[0075] In the following Examples, levoglucosan, which is a 1,6-anhydrosugar, was used as the intramolecularly dehydrated sugar. Levoglucosan was a product manufactured by Fujifilm Wako Chemicals Corporation and had a purity of higher than 97%.

[0076] In the following Examples, PK208LH (trade name, manufactured by Mitsubishi Chemical Corporation) was used as a cation exchanger, which is a solid acid catalyst. The cation exchanger was caused to swell with an alcohol compound that was used as a reactant, before use. Swelling of the cation exchanger was performed by circulating the alcohol compound through a packed bed of the cation exchanger by an ordinarily used method.

Example 1

[0077] Reactants (ethanol as the alcohol compound, and the levoglucosan as the intramolecularly dehydrated sugar) and a cation exchanger were brought into contact with each other by a batch method without using a solvent other than ethanol (in the absence of a solvent), which was a reactant, to produce ethyl glycoside.

[0078] Specifically, ethanol and levoglucosan were mixed at 60° C. to prepare a preliminary mixture having a levoglucosan concentration of 0.30 mol/L. This preliminary mixture was an ethanol solution of levoglucosan.

[0079] Next, 60 g of the obtained preliminary mixture (60° C.) was introduced into a glass reactor, and a cation exchanger (ethanol-swollen product of the above-described PK208LH) preheated to 60° C. was introduced into the glass reactor to a concentration of 33% by mass of the total reaction system. This glass reactor (reaction mixture and cation exchanger) was shaken for 6 hours under the atmospheric pressure conditions and under the conditions of a shaking width of 50 mm and a shaking rate of 150 spm to perform an addition reaction.

[0080] During the addition reaction, a small amount of the reaction liquid was collected at predetermined time intervals, the reaction liquid was diluted with ethanol, the conversion ratio of levoglucosan was traced and determined by using an HPLC (Waters Corp., Milford, Mass., USA) system under the following conditions. As a result, the conversion ratio of levoglucosan calculated by the following Formula 1 became 100% after 6 hours.

(HPLC Measurement Conditions)

[0081] The measurement of HPLC can be carried out by appropriately applying a known method that is used for an analysis of a general sugar or sugar fatty acid ester. For example, measurement can be made by using a reversed phase column (ODS column or the like) or an NH.sub.2 column was used as a column and an RI (differential refractive index meter) or an ELS (evaporation light scattering system) as a detector and using a water/acetonitrile mixed solution as an eluent. In the present Example, an NH.sub.2 column was used as a column and an ELS was used as a detector, respectively.

(Conversion Ratio Calculation Formula for Levoglucosan)

[0082]
Conversion ratio (%)={(C.sub.LG,0−C.sub.LG,t)/C.sub.LG,0}×100  (Formula 1)

[0083] In Formula 1, C.sub.LG,0 designates the levoglucosan concentration (charging concentration) used for the addition reaction, and

[0084] C.sub.LG,t designates the (unreacted) levoglucosan concentration in the reaction liquid after a lapse of the reaction time t.

Example 2

[0085] n-Butyl glycoside was produced in the same manner as in Example 1, except that n-butanol was used instead of ethanol used in Example 1 as the alcohol compound, and the addition reaction time was set to 3 hours. The prepared preliminary mixture had a slight amount of levoglucosan undissolved in n-butanol; however, after completion of the addition reaction, undissolved levoglucosan was not recognized, and the preliminary mixture was obtained as a reaction liquid.

[0086] In Example 2, the conversion ratio of levoglucosan became 100% after 3 hours.

Example 3

[0087] n-Hexyl glycoside was prepared in the same manner as in Example 1, except that n-hexanol was used instead of ethanol used in Example 1 as the alcohol compound, and the addition reaction time was set to 2 hours. The prepared preliminary mixture was a dispersion liquid in which a portion of levoglucosan was dissolved in n-hexanol; however, after completion of the addition reaction, undissolved levoglucosan was not recognized, and the preliminary mixture was obtained as a reaction liquid.

[0088] In Example 3, the conversion ratio of levoglucosan became 100% after 2 hours.

Example 4

[0089] n-Octyl glycoside was produced in the same manner as in Example 1, except that n-octanol was used instead of ethanol used in Example 1 as the alcohol compound, and the addition reaction time was set to 3 hours. The prepared preliminary mixture was a dispersion liquid in which a portion of levoglucosan was dissolved in n-octanol; however, after completion of the addition reaction, undissolved levoglucosan was not recognized, and the preliminary mixture was obtained as a reaction liquid.

[0090] In Example 4, the conversion ratio of levoglucosan became 100% after 3 hours.

[0091] The conditions and results of Examples 1 to 4 are summarized below.

TABLE-US-00001 TABLE 1 Example Alcohol compound Solvent Conversion ratio (%) 1 Ethanol None ~100 2 n-Butanol None ~100 3 n-Hexanol None ~100 4 n-Octanol None ~100

[0092] As is obvious from the results shown in Table 1, in the method of producing an aliphatic glycoside compound, due to a characteristic synthesis reaction in which instead of a sugar that has been conventionally used as a starting raw material, an intramolecularly dehydrated sugar whose utilization has not been hitherto focused is used to perform an addition reaction with an alcohol compound in the presence of a cation exchanger, in all of Examples 1 to 4, even when the type of the alcohol compound and the reaction conditions are changed, the occurrence of the above-described side reactions can be effectively suppressed at a conversion ratio of the intramolecularly dehydrated sugar of almost 100%, and the addition reaction can be accomplished.

[0093] As described above, in Examples 1 to 4, since the occurrence of the above-described side reactions in the absence of a solvent is effectively suppressed, and the reaction proceeds at a conversion ratio of about 100%, the reaction liquid obtained in each Example becomes a mixture of an aliphatic glycoside compound as an addition reactant and an unreacted alcohol compound. Therefore, an aliphatic glycoside compound can be obtained by conveniently removing the alcohol compound by an ordinarily used method. Incidentally, since the aliphatic glycoside compound may be present in the inner part or on the surface of the cation exchanger, an increase in the yield of the aliphatic glycoside compound can be expected by collecting these aliphatic glycoside compounds from the cation exchanger by an ordinarily used method (for example, the above-described regeneration treatment).

[0094] As a result, it can be seen that the present invention can produce a high-purity aliphatic glycoside compound in which coloration as well as the contamination of by-products are highly suppressed.

[0095] Moreover, the production process of the present invention can accomplish the addition reaction by a convenient operation of bringing reactants into contact with an acid catalyst (preferably, a solid acid catalyst), under relatively mild conditions (atmospheric pressure, 60° C.) in Examples 1 to 4. Further, in a suitable embodiment of the present invention, the above-described separation step for the acid catalyst, and isolation and purification (purification step) of the aliphatic glycoside compound from the reaction mixture can also be conveniently carried out. Such a convenient production process can also be suitably applied to (established in), for example, a continuous method of passing through a column packed with a cation exchanger as a solid acid catalyst.

[0096] Moreover, since commercially available aliphatic glycoside compounds are relatively expensive, the present invention by which an aliphatic glycoside compound can be produced at a high conversion ratio (high purity) by a convenient process by using an intramolecularly dehydrated sugar, has high industrial applicability, even from the viewpoint of adding a new value of utilization to intramolecularly dehydrated sugars (thermal decomposition by-products of non-edible biomass).

[0097] Having described our invention as related to the present embodiments, it is our intention that the invention not be limited by any of the details of the description, unless otherwise specified, but rather be construed broadly within its spirit and scope as set out in the accompanying claims.

[0098] The present application claims priority of Japanese Patent Application No. 2020-094792 filed in Japan on May 29, 2020, which is herein incorporated by reference as part of the present specification.