JP2006069920A - Manufacturing method of sucrose fatty acid ester - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a sucrose fatty acid ester capable of removing DMSO as a reaction solvent from the finally produced sucrose fatty acid ester by simple equipment and a simple treatment without using an extraction solvent or the like as much as possible at the time of acquisition of the sucrose fatty acid ester from a reaction mixture. <P>SOLUTION: In the manufacturing method of the sucrose fatty acid ester comprising distilling out or removing dimethyl sulfoxide from a mixture of sucrose fatty acid esters containing dimethyl sulfoxide as the reaction solvent, at least a part of the reaction solvent is distilled out or removed from the mixture of sucrose fatty acid esters and subsequently steam is supplied into the mixture of sucrose fatty acid esters under a heated condition under reduced pressure to remove the reaction solvent. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing a sucrose fatty acid ester.

  Since sucrose fatty acid ester has excellent interfacial performance, good biodegradability and high safety, it has traditionally been used as an additive for foods, cosmetics, pharmaceuticals, kitchen detergents, feeds, resins, etc. In industry, for example, it is used as an auxiliary for reaction systems such as polymerization reaction and oxidation reaction, and is a very useful compound.

  Conventionally, as a method for producing a sucrose fatty acid ester, there is a method of reacting sucrose with a fatty acid alkyl ester in the presence of an alkali catalyst in a reaction solvent such as dimethylformamide or dimethyl sulfoxide (hereinafter abbreviated as DMSO). It is used. The method using DMSO as the reaction solvent can carry out the reaction at a relatively low temperature, and the reaction can be advanced by removing the by-produced alcohol out of the reaction system.

  In this method, DMSO, which is a reaction solvent, must be removed from the finally obtained sucrose fatty acid ester after completion of the reaction. For example, the DMSO can be removed by adding an organic solvent and an organic solvent to the reaction mixture. Add water and liquid-liquid extraction to obtain an organic solvent solution containing sucrose fatty acid ester, then add water to this organic solvent solution and remove most of the organic solvent by azeotropic distillation, and finally A method (Patent Document 1) has been proposed in which a remaining organic solvent is completely removed by treatment with a thin film evaporator.

  However, in the method described in Patent Document 1, since an organic solvent and water are added to the reaction mixture and liquid-liquid extraction is performed, the organic solvent used for extraction is removed from the organic solvent layer containing the sucrose fatty acid ester after liquid-liquid extraction. There is a need to. In order to remove the organic solvent used for the extraction, complicated steps such as a distillation step increase, and a large number of facilities are required. Moreover, since an organic solvent is used for extraction, there is a problem that there is always a risk of fire and explosion.

  Therefore, when the sucrose fatty acid ester is taken out from the reaction mixture after completion of the reaction, it is a reaction solvent from the sucrose fatty acid ester finally obtained with simple equipment and simple processing without using an extraction solvent or the like as much as possible. There is a need for a method for producing sucrose fatty acid esters that removes DMSO.

JP-A-7-206889

  In view of the above problems, the present invention eliminates the use of an extraction solvent or the like as much as possible when taking out a sucrose fatty acid ester from a reaction mixture after completion of the reaction, and can be finally obtained with simple equipment and simple processing. It is an object of the present invention to provide a method for producing a sucrose fatty acid ester capable of removing DMSO as a reaction solvent from the sugar fatty acid ester.

  As a result of intensive studies to solve the above problems, the inventors of the present invention have distilled or removed at least part of DMSO from the reaction mixture after completion of the reaction, and further, in the reaction mixture under reduced pressure heating conditions. It was found that DMSO can be removed from the reaction mixture by supplying water vapor to the present invention, and the present invention has been completed.

That is, the present invention relates to a method for producing a sucrose fatty acid ester in which the reaction solvent is distilled off or removed from a sucrose fatty acid ester mixture containing dimethyl sulfoxide as a reaction solvent.
Evaporating or removing at least part of the reaction solvent from the sucrose fatty acid ester mixture, and then supplying water vapor into the sucrose fatty acid ester mixture under reduced pressure heating conditions to remove the reaction solvent. A method for producing a characteristic sucrose fatty acid ester is provided.

  After completion of the reaction, at least a part of DMSO in the reaction mixture is distilled off or removed, and then water vapor is supplied to the reaction mixture under reduced pressure heating conditions, so that the partial pressure of DMSO decreases, and the DMSO is easily removed from the reaction mixture. Can be removed.

In the method for producing a sucrose fatty acid ester of the present invention, when the sucrose fatty acid ester is taken out from the reaction mixture, the sucrose fatty acid finally obtained with simple equipment and simple treatment is used without using an extraction solvent or the like as much as possible. The reaction solvent DMSO can be removed from the ester.
In the method for producing a sucrose fatty acid ester of the present invention, liquid-liquid extraction is not performed when obtaining the sucrose fatty acid ester from the reaction mixture, so that no equipment such as an extraction tower is required, and further, an organic extractor is used. Since the solvent is not used as much as possible, the risk of fire and explosion can be greatly reduced.

The method for producing a sucrose fatty acid ester according to the present invention comprises the step of distilling or removing the reaction solvent from a mixture of sucrose fatty acid esters containing dimethyl sulfoxide as a reaction solvent. At least a part of the reaction solvent is distilled or removed from the ester mixture, and then water vapor is supplied into the sucrose fatty acid ester mixture under heating under reduced pressure to remove the reaction solvent.
The present invention will be described below.

First, raw materials used for production of sucrose fatty acid ester will be described.
Although there is no restriction | limiting in particular as sucrose in this invention, Usually, a granulated sugar, a saccharose, etc. are used.

Examples of the fatty acid alkyl ester in the present invention include saturated or unsaturated fatty acids having 6 to 30 carbon atoms, preferably 12 to 22 carbons (for example, caproic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, etc. Saturated esters of fatty acids; unsaturated fatty acids such as linoleic acid, oleic acid, linolenic acid, erucic acid and ricinoleic acid) and esters of lower alcohols having 1 to 6 carbon atoms (for example, methanol, ethanol, propanol, butanol, etc.) be able to.
Such fatty acid alkyl esters may be used as a mixture of two or more.
The fatty acid alkyl ester is usually used in an amount of 0.1 to 20 mol, preferably 0.2 to 8 mol, per 1 mol of sucrose.

As the reaction solvent, DMSO, which is an aprotic polar solvent, is used from the viewpoints of thermal stability, solubility in sucrose, and safety. The amount of the solvent used is usually 0.2 to 5 times, preferably 0.3 to 4 times the total charge (parts by weight) of sucrose and fatty acid alkyl ester.
When the amount of DMSO used is less than 0.2 times, there is a problem that sucrose is not completely dissolved and the reactivity is remarkably lowered.
Further, when the amount of DMSO used exceeds 5 times, the concentration of the reaction product in the reaction system is lowered, so that there is a problem that the reaction time is increased and the reactivity is lowered.

  As the alkali catalyst, an alkali metal hydride, an alkali metal hydroxide, an alkali metal salt of a weak acid, or the like is effective, and an alkali metal carbonate (for example, anhydrous potassium carbonate) is particularly preferable. For example, the usage-amount of anhydrous potassium carbonate is 0.001-0.1 mol normally with respect to 1 mol of fatty-acid alkylesters.

The reaction of the sucrose of the present invention with a fatty acid alkyl ester can be carried out according to a known transesterification reaction.
The reaction method uses a reactor equipped with a reflux condenser or a reactor equipped with a fractionation tower as necessary, charged with a predetermined amount of raw materials, solvent, and alkali catalyst and heated to a predetermined temperature under reduced pressure. And while maintaining the reaction system in a boiling state.
The reaction solvent is refluxed into the system by the reflux condenser, and alcohol produced as a by-product is caused to flow out of the reaction system.

The reaction temperature in the transesterification reaction is usually in the range of 40 to 170 ° C, particularly preferably in the range of 60 to 150 ° C. The reaction pressure is usually in the range of 0.2 to 43 kPa, and particularly preferably in the range of 0.7 to 32 kPa.
The reaction time for the transesterification reaction is usually 1 to 30 hours.

Next, the process after completion | finish of the said transesterification reaction is demonstrated.
After completion of the transesterification reaction, an acid equivalent to the alkali catalyst used in the reaction is added to neutralize the catalyst.
Examples of the acid used for the neutralization include organic acids such as lactic acid, formic acid, acetic acid, propionic acid, tartaric acid, oxalic acid, succinic acid, citric acid, maleic acid, malic acid, and benzoic acid.
The pH of the reaction mixture after neutralization is in the range of pH 5 to pH 8, preferably pH 5.5 to pH 6.5.
When the pH after neutralization is less than 5, the produced sucrose fatty acid ester is decomposed.
Moreover, when pH after neutralization exceeds 8, the produced | generated sucrose fatty acid ester decomposes | disassembles.

At least a portion of DMSO is distilled off or removed from the neutralized reaction mixture. By removing a part of DMSO by distillation or the like, it is possible to reduce the amount of removal in the process of supplying DM, which will be described later, to remove DMSO.
Here, the amount of DMSO to be distilled off is about 7/10 to 9.5 / 10, assuming that DMSO used in the reaction is 1.
When the amount to be distilled off is less than 7/10, it takes a long time to remove DMSO by supplying water vapor described later, which is inefficient.
On the other hand, when the amount to be distilled off exceeds 9.5 / 10, the heating time becomes long, and the produced sucrose fatty acid ester is colored and decomposed.

When at least a part of DMSO is distilled or removed from the reaction mixture, the reaction mixture is heated under reduced pressure.
The temperature for distilling off DMSO from the reaction mixture is 80 to 140 ° C., preferably 90 to 120 ° C.
If the temperature when the solvent is distilled off exceeds 140 ° C., the produced sucrose fatty acid ester may be colored and decomposed.
In addition, the degree of reduced pressure when distilling off DMSO from the reaction mixture is 1 to 15 kPa, preferably 1 to 8 kPa.

  A method for further removing DMSO from the reaction mixture obtained by distilling or removing at least a part of DMSO will be described. As described above, the DMSO is removed from the reaction mixture by supplying steam to the reaction mixture under reduced pressure and heating conditions, and lowering the partial pressure of DMSO.

The amount of water vapor supplied to the reaction mixture obtained by distilling off DMSO is 0.1 to 5 times, preferably 0.15 to 2 times, assuming that the reaction mixture obtained by distilling DMSO is 1.
When the amount of the water vapor is less than 0.1 times, DMSO cannot be sufficiently removed, and much DMSO remains.
Further, if the amount of the water vapor exceeds 5 times, the effect of supplying the water vapor becomes constant, so that the water vapor is wasted and uneconomical.

The temperature under the reduced pressure heating condition is 80 to 140 ° C, preferably 90 to 120 ° C.
If the temperature is less than 80 ° C., the DMSO removal efficiency may decrease.
Moreover, when temperature exceeds 140 degreeC, there exists a possibility that the produced | generated sucrose fatty acid ester may color and decompose.

The degree of decompression is 15 kPa or less, preferably 8 kPa or less.
If the degree of vacuum exceeds 15 kPa, the DMSO removal efficiency may be reduced.
In addition, as an apparatus for achieving the said pressure reduction degree, pumps, such as a mechanical vacuum pump and a diffusion pump, a gas ejector, a steam ejector, etc. can be used.

  According to the method for producing a sucrose fatty acid ester of the present embodiment, the DMSO content in the reaction mixture can be suppressed to 0.9 ppm or less, and a high-purity sucrose fatty acid ester can be obtained efficiently.

  The present invention will be described more specifically with reference to examples, but the present invention is not limited thereto.

(Method for measuring the concentration of dimethyl sulfoxide)
The DMSO concentration in the reaction mixture was measured by the following method.
The reaction mixture is diluted with THF (tetrahydrofuran) to a DMSO concentration of 1 to 5 ppm. 0.5 μl of the diluted solution was injected into a gas chromatography manufactured by Shimadzu Corporation, and the DMSO concentration was measured. The concentration was determined by comparison with a calibration curve prepared in advance.
Gas chromatography: Shimadzu Corporation GC-14A
Column used: GL Sciences, Chromoso-b WAW DMCS
Gas flow rate: Using Gas N _2, the flow rate 1.5~1.8kg / cm ²

Example 1
A 2 L reactor was charged with 661.7 g of DMSO and heated to 3.7 kPa under reduced pressure. A part of the steam was distilled out of the system to remove the water in the system, and when the water content in the system reached 0.05%, the distillation of the steam was stopped, and then 92.8 g of sucrose was obtained. 432.2 g of methyl stearate and 5.2 g of anhydrous potassium carbonate were added, and sucrose and stearate methyl methyl were reacted at about 95 ° C. under a reduced pressure of 4.0 kPa. The molar ratio of methyl stearate to sucrose was 5.1.
After completion of the reaction, 5.5 g of lactic acid in an equal amount with respect to potassium carbonate was added to neutralize the potassium carbonate. Subsequently, the reaction mixture was desolvated by heating under reduced pressure at 2.5 kPa and 100 ° C., and the reaction mixture was 90.0% sucrose fatty acid ester, 0.01% unreacted sucrose, 4.8% DMSO, and other 5.2%. 500 g was obtained.
To the reaction mixture after desolvation, steam was internally supplied at a rate of 5.0 g / min for 150 minutes under the conditions of an internal temperature of 120 ° C. and an internal pressure of 8 kPa, and 1.6 times the steam of the reaction mixture (solid content). 750 g was supplied. As a result, the concentration of DMSO was 2 ppm.

(Example 2)
The experiment was performed in the same manner as in Example 1 except that the internal temperature was 120 ° C. and the internal pressure was 8 kPa instead of the internal temperature of 120 ° C. and the internal pressure of 8 kPa.
As a result, the concentration of DMSO was 1100 ppm.

(Example 3)
The experiment was performed in the same manner as in Example 1 except that the internal temperature was 120 ° C. and the internal pressure was 8 kPa instead of the internal temperature of 120 ° C. and the internal pressure of 8 kPa.
As a result, the concentration of DMSO was 880 ppm.

Example 4
The experiment was performed in the same manner as in Example 1 except that the internal temperature was 120 ° C. and the internal pressure was 8 kPa instead of the internal temperature of 120 ° C. and the internal pressure of 8 kPa.
As a result, the concentration of DMSO was 0.9 ppm.

(Example 5)
The experiment was performed in the same manner as in Example 1 except that the internal temperature was 120 ° C. and the internal pressure was 8 kPa instead of the internal temperature of 120 ° C. and the internal pressure of 8 kPa.
As a result, the sucrose fatty acid ester was colored and decomposed.

(Example 6)
The experiment was performed in the same manner as in Example 1 except that the conditions of the reduced pressure heating were changed to an internal temperature of 150 ° C. and an internal pressure of 20 kPa instead of the internal temperature of 120 ° C. and the internal pressure of 8 kPa.
As a result, the sucrose fatty acid ester was colored and decomposed.

(Comparative Example 1)
The experiment was performed in the same manner as in Example 1 except that water vapor was supplied under the conditions of reduced pressure heating under the conditions of an internal temperature of 120 ° C. and an internal pressure of 8 kPa.
As a result, the DMSO concentration was 20665 ppm.

(Comparative Example 2)
The experiment was performed in the same manner as in Example 1 except that the internal temperature was 120 ° C. under reduced pressure heating conditions, and water vapor was supplied internally at a rate of 5.0 g / min without reducing pressure.
As a result, the DMSO concentration was 45012 ppm.

  Table 1 shows the results of Example 1, Example 2, Comparative Example 1, and Comparative Example 2.

  Table 2 shows the results of Examples 1 to 6.

  In Examples 1 and 4, the DMSO concentration could be very low, and DMSO could be removed from the sucrose fatty acid ester.

Claims (3)

In the method for producing a sucrose fatty acid ester, the reaction solvent is distilled off or removed from the sucrose fatty acid ester mixture containing dimethyl sulfoxide as a reaction solvent.
Evaporating or removing at least a portion of the reaction solvent from the sucrose fatty acid ester mixture;
Next, a method for producing a sucrose fatty acid ester is characterized in that water vapor is supplied into the sucrose fatty acid ester mixture under reduced pressure heating conditions to remove the reaction solvent.   The method for producing a sucrose fatty acid ester according to claim 1, wherein the heating conditions are a degree of vacuum of 15 kPa or less and a temperature of 80 to 140 ° C.   A sucrose fatty acid ester obtained by the method for producing a sucrose fatty acid ester according to claim 1 or 2.