JPS61238749A - Production of polyglycerol - Google Patents

Abstract

PURPOSE:To obtain the titled compound having excellent color tone, high content of 2-4-mer and low cyclic product content and usable safely as a raw material of food additive, by condensing glycerol in the presence of an alkali catalyst in combination with aluminum oxide adsorbent. CONSTITUTION:Glycerol is condensed in the presence of an alkali catalyst (especially preferably an alkali metal carbonate such as potassium carbonate, sodium carbonate, etc., because of the nonhygroscopic powdery nature). The reaction is carried out in the presence of 0.1-5pts.wt., preferably 0.5-2.5pts.wt. of an aluminum oxide adsorbent such as active alumina, aluminum oxide reagent, etc., per 100pts.wt. of glycerol to obtain a polyglycerol (having high content of 2-4-mers and containing <=10wt% high-molecular polyglycerols of >=7-mer and little cyclic compounds). USE:Base for food emulsifier and cosmetics.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a method for producing polyglycerin having a good hue, a high content of dimers or tetramers (and a small amount of cyclic products), The polyglycerin produced according to the invention can be safely used as a food emulsifier base or a cosmetic base.

[Conventional technology]

Conventionally, methods for producing polyglycerin are broadly classified into the following three methods.

(1) Condensation of glycerin A method of condensing glycerin by heating it to 220 to 280° C. in a nitrogen or carbon dioxide atmosphere in the presence of an alkali catalyst.

(2) Recovery of glycerin from distillation residue A method of extracting the residue produced when natural or synthetic glycerin is distilled using an organic solvent such as alcohol or dioxane.

(3) Epichlorohydrin method A method of manufacturing by adding a concentrated aqueous sodium hydroxide solution to epichlorohydrin and condensing it.

According to these methods, in any case, the product is colored dark brown due to side reactions, generates an unpleasant odor, and contains a large amount of cyclic polyglycerin in addition to linear polyglycerin. Therefore, in order to produce a product, further purification steps such as steam deodorization, activated carbon treatment, activated clay treatment, and ion exchange resin treatment are required.

Furthermore, a method has been proposed in which an alkali catalyst and a reducing agent (metallic aluminum or metallic magnesium) are added during condensation of glycerin to produce polyglycerin with a good hue. The Journal.

Of, The, American, Oil, Chemistry 9 Society (JAOC3) Volume 58, Page 878 (1981)
[Problems to be Solved by the Invention] Polyglycerin obtained by these conventional methods generates cyclic polyglycerin in addition to chain polyglycerin during the condensation process. Cyclic polyglycerin is questionable as to its safety for the human body, and poses a problem when it is derived into polyglycerin fatty acid ester or polyglycerin ricinoleic acid ester as a food additive. In reality,
The reason why the hydroxyl value of polyglycerin is smaller than the theoretical value is due to the cyclization caused by this intramolecular ester condensation.

Furthermore, FAOFOOD AND NtlTRITION
PAPER 4 (Food and Agriculture Organization of the United Nations, published in 1978), pages 270-271, regarding polyglycerin fatty acid esters as food additives, states that the sum of diglycerin, triglycerin, and tetraglycerin in the polyglycerin portion is 75% by weight or more. , and the content of high molecular weight polyglycerin higher than heptaglycerin is specified to be 10% or less.

However, according to the conventional method, when attempting to increase the content of diglycerin, triglycerin, and tetraglycerin, that is, dimers or tetramers, the content of unreacted glycerin also increases, so operations such as distillation are required. It takes time and effort to remove unreacted substances. Furthermore, if an attempt is made to reduce the content of unreacted substances, the amount of high molecular weight polyglycerin greater than heptaglycerin exceeds 10% by weight, the amount of cyclic polyglycerin increases, and the hue further deteriorates.

[Means to solve the problem]

The present invention solves the above problem, and is characterized in that an alkali catalyst and an aluminum oxide adsorbent are added to glycerin and condensed therein. That is, according to the present invention, in which an aluminum oxide adsorbent is used in the condensation reaction of glycerin in the presence of an alkaline catalyst, the color is good, the content of dimers to tetramers is high, the amount of cyclic polyglycerin is low, and food additives can be obtained. It is possible to produce polyglycerin that can be safely used as a raw material.

In the present invention, the alkali catalyst used for condensation is
Potassium carbonate, sodium carbonate, lithium carbonate, potassium hydroxide, sodium hydroxide, lithium hydroxide, sodium bicarbonate, sodium methylate, calcium oxide, magnesium oxide, calcium carbonate, magnesium carbonate, zinc oxide, and the like can be used. Among these, alkali metal carbonates such as potassium carbonate, sodium carbonate, and lithium carbonate are particularly preferred because they are powdery and non-hygroscopic.

The amount added is not particularly limited, and is 0.1 to 5 parts by weight, preferably 0.5 to 5 parts by weight, per 100 parts by weight of glycerin.
It is 2.5 parts by weight.

Aluminum oxide-based adsorbents include activated alumina, aluminum oxide reagents, etc., and may be aluminum oxide itself, but adsorbents containing aluminum oxide, such as activated clay, zeolite, and synthetic adsorbents (for example, Kyowa Chemical Co., Ltd.)
(product name: Kyoward) etc. are also used, in this case,
The content of the aluminum oxide component is required to be 5% by weight or more. The amount added is not particularly limited, but is usually 0.1 to 5 parts by weight, preferably 0.5 to 2.5 parts by weight, per 100 parts by weight of glycerin.

The condensation reaction is carried out under the usual conditions for glycerin condensation reaction in the presence of an alkali catalyst. For example, glycerin is heated in a nitrogen or carbon dioxide atmosphere, moisture is removed at 100 to 200°C, an alkali catalyst and an aluminum oxide adsorbent are added, and the temperature is raised to 240 to 260°C. ~l
Allow to react for O hours.

[Effect]

In the present invention, the aluminum oxide adsorbent used together with the alkaline catalyst has a catalytic effect as a solid acid in addition to its decolorizing effect during the reaction, and is effective in controlling the degree of polymerization and suppressing cyclization. It is thought that this has an effect.

〔Effect of the invention〕

According to the present invention, a polyester resin having a good hue, a high content of dimers or tetramers, a content of high molecular weight polyglycerin higher than heptaglycerin of 10% by weight or less, and a low content of cyclic bodies is produced. Glycerin is obtained. Therefore, the polyglycerin according to the present invention satisfies the F'A○ standard for fatty acid esters of polyglycerin, and can be safely used as a raw material for food additives.

〔Example〕

In the following examples, parts and percentages are by weight, respectively.

100 parts of glycerin was placed in a four-hole flask equipped with a stirrer, and heated with a mantle heater while blowing nitrogen gas into the glycerin. The amount of nitrogen gas blown is 2ml
/min·g glycerin.

After raising the temperature to 150°C, this temperature was maintained for 30 minutes to distill off the moisture in the glycerin. Next, the alkaline catalyst and aluminum oxide adsorbent shown in Table 1 were added, and the mixture was heated at 250°.
The condensation reaction was carried out for 5 hours at elevated temperature.

The reaction solution was cooled to 100°C, 80 parts of ion-exchanged water was added, and then 4 parts of powdered activated carbon was added, stirred at 80°C for 30 minutes, and then filtered. The obtained decolorized polyglycerin aqueous solution was mixed with H-type strongly acidic ion exchange resin PK-216 (Mitsubishi Kasei side part) and OHH-type strongly acidic ion exchange resin PA1308.
The solution was passed through a 1:1 mixed bed column (manufactured by Mitsubishi Kasei@) at a superficial velocity of 3 to perform decolorization and decatalyst removal.

Finally, dehydration was performed using a thin film distiller at a vacuum degree of 5 mmHg and a temperature of 150° C. to obtain the desired polyglycerin. The results are shown in Table 1.

The activated clay is Vz5UPER manufactured by Mizusawa Kagaku ■.

Aluminum oxide content was 10.4%, Alx Oi was a special reagent grade, Kyoward was Kyoward 300 (made by Kyowa Kagaku ■) and aluminum oxide content was 26.3%, and zeolite was from Mizusawa Kagaku side type.

As a comparative example, a test was conducted in the same manner as in the example except that no aluminum oxide adsorbent was used, and the results are shown in Table 2.

The hue and polyglycerin composition were analyzed by the following method.

(Dark colored samples were measured by the Gardner method, and light colored samples were measured by the APHA method, according to 11 Hue Standard Oil and Fat Analysis Test Method 2.3°■-71.

Table 1-1 Table 1-2 Table 2 (2) It is difficult to accurately analyze the degree of polymerization distribution and the amount of cyclic polyglycerin;
-i column gas chromatography and TSK-G
High performance liquid chromatography using EL (manufactured by Toyo Soda Kogyo ■) cannot provide a satisfactory sharp analysis.

The inventors used fused gas chromatography because they found it to be the most suitable analytical method and provided accurate results.

The sample used was trimethylsilylated according to a conventional method. Capillary gas chromatography was performed under the following conditions.

Equipment: HEWLETT PACKERD 5710A
GAS CHROMATOGRAPH column: Me
tyl 5ilicone 10m Xo, 31mm
φFused 5ilica Capillary Oven temperature: 100-350℃ (heating rate 16℃/min) Detector temperature: 350℃ Injection temperature: 5plit (100:1)
300℃ Carrier gas: Helium 0.5 ml/l Detector: FID, Hydrogen 30 ml/min As an example of a gas chromatograph using this analysis method, the results of sample No. 4 and sample No. 10 are shown in Figures 1 and 1. It is shown in Figure 2.

[Brief explanation of drawings]

Figure 1 shows polyglycerin obtained in the present invention, sample No.
Figure 2 shows the gas chromatograph of Sample No. 10, a polyglycerin obtained by the conventional technique. In both FIG. 1 and FIG. 2, the components corresponding to each peak number are as follows.

Claims (1)

[Claims] A method for producing polyglycerin, which comprises adding an alkali catalyst and an aluminum oxide adsorbent to glycerin and causing condensation.