JPS6026399B2 - Method for producing sucrose fatty acid ester - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for producing sucrose fatty acid ester.

Until now, many proposals have been made regarding methods for producing sucrose fatty acid esters, and some have been industrialized. They are mainly classified into the following three types. The first method is called the solvent method, in which a solvent that dissolves both sucrose and fatty acid derivatives, such as dimethylformamide or dimethyl sulfoxide, is used to react in a homogeneous solution.
It is undesirable that the reaction proceeds at a low temperature of about 90°C, but since the solvent is toxic, it must be completely removed from the product, which requires laborious work, which is industrially disadvantageous. ing.

The second method is commonly referred to as the microemulsion method, in which a solution of sucrose dissolved in a solvent such as propylene glycol or water and a fatty acid conductor are mixed together using a suitable emulsifier, such as a fatty acid soap. In this method, a fine dispersion system, that is, a microemulsion is formed, and then the solvent is distilled off and the reaction is carried out.

Although this method is advantageous in that it does not use harmful solvents unlike the solvent method, it is highly technically difficult to remove the solvent while maintaining the microemulsion state. The third method is a method in which sucrose and fatty acid ester are directly mixed and heated to cause the two to react without using any solvent, and is called the immediate method.

The important point of the direct method is how to mix the raw materials, sucrose and fatty acid ester, which have no affinity with each other, and bring them into a state where they can react.

Several methods have been proposed in this regard. For example, the method of Mochiko Sho 49-41171 is a method in which sucrose and fatty acid ester are melted at an extremely high temperature of 160 to 190 qo, and the reaction is carried out using alkaline soap as a catalyst, which does not contain any free alkali. It is difficult to produce alkaline soap that does not contain any alkaline soap, and since the reaction is carried out near the decomposition temperature of sucrose, the purity of the product obtained by the decomposition reaction is poor, making it difficult to implement it industrially.

In addition, the method of Tsubaki Batsu 196518 is to saponify a fatty acid ester with an equivalent amount of alkali or less in a solvent system such as methanol, to first prepare a mixture of the fatty acid ester and its alkaline soap, and then distill off the solvent from there. This method involves creating a molten mixture of both and adding sucrose to it to cause a reaction. The method disclosed in Tsubaki Seki Sho 51-39621 is characterized in that a molten mixture is prepared from sucrose and an alkali with the help of a small amount of a solvent such as water, and this is reacted with a fatty acid ester.

However, methods for producing a melt using these solvents require an operation to remove the solvent, and have the disadvantage that phase separation during removal tends to result in a non-uniform molten mixture. Furthermore, JP-A-5
1-65704 proposes a method in which sucrose and fatty acid ester are directly reacted at atmospheric pressure without using a solvent or melting sucrose; Since the reaction is carried out in a heterogeneous system with a liquid fatty acid ester, it is obvious that it is inferior to a method in which the reaction is carried out in a homogeneous system in terms of reaction rate and other aspects. The present invention is based on the discovery that when sucrose and fatty acid ester are added to a melt of anhydrous fatty acid soap, these three easily melt completely to form a homogeneous composition. It is. That is, an amount of anhydrous fatty acid soap sufficient to create a uniform melt of the three components, specifically at least 10% of the weight of the entire uniform melt, preferably 15 to 3
Heat and melt 0% fatty acid anhydride soap for about 10 minutes,
When sucrose and fatty acid ester were added to the mixture and heated while stirring, and the behavior was tracked using a differential thermal analyzer, an endothermic phenomenon was observed at 125qC, and visually the three components formed a homogeneous molten mixture. I found out the truth. In this case, it has been found that if a solvent such as water or ethanol is added in advance, even in a small amount, this phenomenon can be inhibited. When the reaction mixture thus molten is stirred and reacted under reduced pressure, sucrose fatty acid ester can be produced in high yield at a relatively low temperature and under light reduced pressure. The present invention relates to the production of sucrose and fatty acid ester by reacting sucrose and fatty acid ester in the presence of a fatty acid soap and an alkali catalyst. Rice bran and fatty acid ester are added to the melt of fatty acid soap at a temperature of 100.degree.
The present invention relates to a method for producing a sucrose fatty acid ester, which is characterized by carrying out a reaction in a step.

The sucrose used in the method of the invention has very few restrictions regarding its quality form.

That is, any solid sucrose such as commercially available granulated sugar or white bran can be used. However, it is preferable to crush crystal particles that are too coarse in advance to make them fine. Preferably, it is in the form of fine particles of 70 mesh or less. The fatty acid ester is an ester of a higher fatty acid having 8 to 22 carbon atoms and a lower monohydric alcohol having 4 or less carbon atoms, which is generally used in the production of sucrose fatty acid ester. The fatty acid component may have unsaturated bonds and/or branched chains. A mixture of fatty acid esters may also be used. The fatty acids used as raw materials for soap are higher fatty acids having 8 to 22 carbon atoms. As above, those having unsaturated bonds and/or branched chains can also be used, and mixtures can also be used. As the alkali that can be used to produce fatty acid soap, non-acid compounds such as potassium carbonate, sodium carbonate, potassium hydroxide, and sodium hydroxide, or organic alkali compounds such as sodium ethylate and potassium methylate are used. It will be done. However, alkali carbonates such as potassium carbonate, sodium carbonate, etc. are preferred since they eliminate the need to remove created materials such as water or solvents after the soap is manufactured. In producing fatty acid soaps, it is not necessary to strictly adhere to the equivalent amount of alkali to fatty acid. The presence of an excess of alkali is not at all a hindrance, but is rather preferred since it acts as a catalyst for the subsequent transesterification reaction. When an alkaline catalyst is to be added separately, the aforementioned alkaline compound is added to the sucrose in an amount of 1 to 10%, preferably 3%.
Add ~7%.

It may be added at the same time as or after adding the bran and fatty acid ester to the molten fatty acid anhydride soap, but if excessive alkali is used during soap production, free alkali may remain in the soap produced. It is most preferable to The soap produced is melted and dehydrated beforehand.

The method is, for example, 10 pi○ or more, preferably 120 to 1
Heat to 4 psi and under reduced pressure of 50 to 20 m Hg.
Achieved by keeping 3 and 8. Sucrose and fatty acid esters are added to the soap thus melted and dehydrated. As for the order of addition, either one may be added first or they may be added at the same time. However, at that time, it is preferable to maintain the temperature at 125°C or higher. In this case, it was found that if too large amounts of sucrose and fatty acid ester were added to a given amount of soap, in other words, if the proportion of soap in the mixture of the three was small, the yield of sucrose fatty acid ester decreased. . The proportion of said soap should therefore be at least 10% of the weight of the entire molten mixture, preferably between 15 and 30%. In this way, the reaction components are combined in a homogeneous phase at 125
The desired sucrose fatty acid ester can be obtained in high yield by reacting under reduced pressure at a temperature of 0 to 165 °C.

The reduced pressure may be mild, for example, a wide range of 20 Kg or less can be used. Although the reaction time depends on the type of raw materials and the reaction temperature, it may generally be 3 to 5 hours. In addition to sucrose ester, the reaction product contains soap, unreacted sucrose, fatty acid ester, etc., so by removing these using a known method, sucrose fatty acid ester with a purity of 95% or more can be produced. I can do it.

As described above, the method of the present invention has the following advantages over conventionally proposed methods.

First, it is easy to produce a molten mixture of sucrose and fatty acid ester.

That is, it is sufficient to simply add sucrose and fatty acid ester to melted anhydrous fatty acid soap and stir, and there are no restrictions on the ratio of sucrose and fatty acid ester or the order of addition. Also, in any case, the mixture easily melts to form a stable homogeneous phase and does not separate. Second, as mentioned above, fatty acid soaps can be easily produced. That is, the ratio of alkali to fatty acid does not need to be strictly equivalent; rather, it is preferable to have a slight excess of alkali so that the soap contains free alkali, which is used as a catalyst for the transesterification reaction. Thirdly, despite the easy operation as mentioned above, the reactivity of the obtained molten product is high, and 12
5-16? Sucrose fatty acid esters can be obtained in higher yields than conventional methods at low temperatures (○) and under mild reduced pressure conditions that are easy to industrialize.

A fourth advantage is that the process of the present invention is easy to operate, as the foaming phenomenon that occurs in the conventional method of reacting sucrose and fatty acid ester in the presence of alkaline soap does not occur at all in the method of the present invention.

The invention and its advantages are demonstrated below by examples and comparative examples.

Example 1 18.7 qo of stearic acid was put into a 500 qo flask equipped with a stirrer, a thermometer, and a pressure reducing device, and 125 qo
Heat to melt.

Next, powdered potassium carbonate9. When the foundation is added and stirred, the two react to form soap. This is 130 times 0,
Stir and dehydrate at low Hg for 20 minutes. Add 7 pieces of powdered sucrose and 52.4 pieces of methyl stearate to this and stir to obtain a homogeneous composition. This was stirred for 3 hours at 14 pi and 10 m Hg, and the brown content obtained was analyzed, and the content of methyl stearate was 1.2%. The reaction rate calculated from this is 96.8%.
The content of sucrose stearate is 43.5%.
The composition was 48% monoester, 35% gester, and 17% triester. Comparative Example 1 (Japanese Patent Publication No. 45-23534) Using the same apparatus as in Example, 61. Thigh, methyl stearate 46. Female, sodium stearate 3 Female, propylene glycol 40
[ of [] was prepared and overflowed with 135 qo to completely dissolve it. Under vacuum (initially 10 mHg), being careful not to bubble.
, gradually increase the temperature and degree of vacuum to remove the propylene grill. Eventually it reached 160 qo, 4 side Hg. Add K2C03 to the shipboard as a catalyst, maintain its temperature and degree of vacuum,
The reaction was allowed to proceed for 3 hours. The obtained contents were colored black, and as a result of analysis, the content of methyl stearate was 3.8.
%, and the reaction rate calculated from this was 87.0%. Comparative Example 2 (Hakama Sekisho 50-1142507 Publication) Powdered sucrose 5 coats, methyl stearate 4 coats, and sodium stearate were put into a 500 flask equipped with a stirrer, thermometer and N2 gas blowing device. .

When the mixture is heated to 15 mm and dissolved, it becomes a viscous maple mixture that is uniform throughout and to the naked eye.

Add 1 cup of potassium carbonate while blowing N2 gas, and continue stirring for 4 hours. The product was blackish brown in color and contained 5.6% of tertyl stearate. Calculating from this, the reaction rate is 86%. Comparative Example 3 (Mochiko Sho 51-14485) In the same apparatus as in the example, 70.
1g sodium stearate21. Thin, methyl stearate 52. Approximately 3 liters of water was added and heated to 13°C to obtain a uniform transparent dispersion.

Most of the water was removed under reduced pressure, potassium carbonate was added as a catalyst, and the reaction was carried out at 155° C. and 25 Hg for 3 hours. The product contained 42.6% sucrose fatty acid esters, and the methyl ester content was 2.4%. The reaction rate is 93.6
%. Comparative Example 4 The order of addition of the reaction components in Example 1 was reversed.

That is, an anhydrous soap containing excess free potassium carbonate prepared in the same manner as in Example 1 was added to a mixture of sucrose and methyl stearate prepared in a separate container;
This was stirred at 14 pi○, low ship Hg. Up to about 1 hour of heating, it was separated into an upper layer of oil and a lower layer containing granular solids, but after about 1 to 1.5 hours, it was almost uniform. It becomes a phase.

Analysis of the contents after 3 hours of reaction revealed that 14.2% of unreacted methyl stearate was still contained, and the content of sucrose stearate was only 27.6%.

Even after 5 hours of reaction, 4.2% of unreacted methyl stearate remained.
Although the sucrose stearic acid content reached 368%, it was strongly colored and difficult to purify.

Example 2 In the same apparatus as in Example 1, oleic acid 35.1
Prepare 120 g and 12.7 g of sodium carbonate.
Anhydrous soap melt 43, reacted for 25 minutes at 80 Hg and containing 61 g of sodium carbonate as free alkali.
．． I got oak.

To this was added one portion of powdered sucrose and three portions of methyl oleate, and the resulting homogeneous composition was heated at 150°C and 60 atmospheres of Hg for 2 hours.
I stirred the time.

The product contained 482% sucrose oleate and only 0.7% unreacted methyl oleate. Comparative Example 5 In Example 2, when the amount of sodium carbonate was reduced by 6.5 to make an anhydrous soap containing no free alkali, and the reaction was carried out under the same conditions, the product sucrose oleic acid The ester content was only 30.4%, and 13.0% of unreacted methyl oleivate remained.

Claims (1)

[Claims] 1. When producing sucrose fatty acid ester by reacting sucrose and fatty acid ester in the presence of a fatty acid soap and an alkali catalyst, anhydrous fatty acid soap that accounts for at least 10% by weight of the entire reaction system and contains free alkali is used. 1. A method for producing a sucrose fatty acid ester, which comprises adding sucrose and a fatty acid ester to a melt, mixing the mixture to form a homogeneous melt, and reacting this at 125 to 165°C.