JPS6368541A - Production of polyglycerin fatty acid ester - Google Patents

Abstract

PURPOSE:To esterify polyglycerin with a fatty acid by the use of an alkali catalyst, to obtain the titled compound useful as an emulsifying agent for food, etc., at a high reaction rate in a short reaction time without requiring purifica tion and causing smell and bitterness, by carrying out the esterification in the presence of sulfurous acid or a sulfite. CONSTITUTION:Polyglycerin is esterified with a fatty acid in the presence of an alkali catalyst and sulfurous acid or a sulfite at 180-260 deg.C to give the aimed compound. The alkali catalyst and sulfurous acid or the sulfite are added usually at normal temperature - 150 deg.C and then the temperature is raised. When the sulfite is used, the sulfite is used as an aqueous solution. Lithium sulfite, etc., are used as the sulfite. The amount of sulfurous acid or the sulfite used is 0.005-10wt%, especially 0.01-1wt% based on total amount of the polyglycerin and the fatty acid. The amount of the alkali catalyst used is preferably 0.01-10wt% based on the total amount of the raw materials.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing polyglycerol fatty acid ester. The polyglycerol fatty acid ester obtained by the present invention is useful as an emulsifier or base in the fields of foods, cosmetics, medicine, etc.

[Conventional technology]

In recent years, polyglycerol fatty acid esters have been approved as food additives, and their usage is gradually increasing. This ester is produced by combining polyglycerin with different polymerization degrees and fatty acids with different chain lengths as raw materials.
It is widely used as an emulsifier and viscosity modifier, especially in the food field, because it yields an ester with a high LB value and exhibits high stability in an acidic region.

The method for producing this polyglycerin fatty acid ester is as follows:
(1) Esterification reaction of polyglycerin and fatty acids, (2
) transesterification reaction between polyglycerin and fatty acid ester, (3) transesterification reaction between polyglycerin and fats and oils, and (4) addition polymerization reaction between glycidol and fatty acid.

Among these methods, methods (2) to (4) have many restrictions due to problems such as reactivity, quality and purity of the produced polyglycerol fatty acid ester, food additive regulations, and industrial production costs. It is.

Method (1) is based on JA OCS (Journal o
f AmericanOil Ches+1sts'
5ociety), Volume 58, Page 878 (1981), discloses a method for obtaining a polyglycerin fatty acid ester by carrying out an esterification reaction between polyglycerin and a fatty acid in the presence of an alkali catalyst.

[Problem that the invention seeks to solve]

According to this method, there is coloration, odor, and bitterness due to the catalyst and high temperature during the reaction, and purification is required for use in foods, cosmetics, medicines, etc. When sufficiently purified polyglycerin and fatty acids are used as raw materials, the coloring and odor are somewhat reduced, but the result is still unsatisfactory and a purification step is still required.

Refining methods include adsorption treatment using clay or activated carbon, which is similar to the refining method for oils and fats, and bleaching treatment using decolorizing agents, but none of them are sufficiently effective, and furthermore, the quantitative and Another drawback is that the time loss is extremely large.

Therefore, there has been a need for a method for producing polyglycerol fatty acid esters through an esterification reaction between polyglycerin and fatty acids, which is free from coloration, odor, and bitterness and requires almost no purification steps.

[Means of problem solving]

The present invention solves the above problem, and is characterized in that when polyglycerin and fatty acid are esterified using an alkali catalyst, the esterification is carried out in the presence of sulfite or sulfite.

As the polyglycerin in the present invention, diglycerin or decaglycerin, and even higher molecular weight polyglycerin can be used. These polyglycerins may be those obtained by polymerizing glycerin obtained from fats and oils or those obtained by ring-opening polymerization of glycidol, but the former is preferable when the polyglycerin fatty acid ester is used for food.

As the fatty acid, a fatty acid having 6 to 22 carbon atoms is used, and may be a saturated fatty acid or an unsaturated fatty acid, a linear fatty acid, a fatty acid having a side chain, or a hydroxyl group-substituted fatty acid. These fatty acids include, for example, caproic acid, caprylic acid, 2-ethylhexanoic acid, capric acid, lauric acid, isotridecanoic acid, myristic acid, valmitic acid, palmitoleic acid, stearic acid,
These include isostearic acid, oleic acid, linoleic acid, behenic acid, erucic acid, ricinoleic acid, and hydroxystearic acid.

Alkali catalysts include alkali metals such as lithium, sodium, and potassium, alkaline earth metals such as magnesium and calcium, and their oxides, hydroxides, alcolades, carbonates, and bicarbonates, which are suitable for normal esterification reactions. You can use whatever is used. The amount of the alkali catalyst used is within the range used in normal esterification reactions, and is 0.01 to 10% by weight based on the total amount of polyglycerin and fatty acid.

Regarding the sulfurous acid or sulfite used in the present invention, it is convenient to use the sulfurous acid as an aqueous solution. Sulfites include, for example, lithium sulfite, sodium sulfite, potassium sulfite, magnesium sulfite, calcium sulfite, sodium hydrogen sulfite, potassium hydrogen sulfite, calcium hydrogen sulfite, and the like. The amount of sulfite or sulfite used is 0.00 based on the total amount of polyglycerin and fatty acids.
It is 5 to 10% by weight, preferably 0.01 to 5% by weight, more preferably 0.01 to 1% by weight. If it is less than 0.005% by weight, the effect of the present invention cannot be obtained, and if it exceeds 10% by weight, hardly any improvement in the effect can be expected.

The esterification reaction is usually carried out at 180 to 260°C, and the addition of the alkali catalyst and sulfite or sulfite is usually carried out at room temperature to 150°C.

The manufacturing method of the present invention can be carried out, for example, as follows.

Polyglycerin is placed in a reaction vessel, stirred while introducing nitrogen gas, and heated to approximately 80°C. Add fatty acids to this, and if solid fatty acids are used, stir until melted. Next, add an alkali catalyst and sulfite or sulfite, raise the temperature to about 210°C, and measure the amount of water distilled out of the reaction system, acid value, saponification value, hydroxyl value, etc. The desired polyglycerin fatty acid ester can be obtained by checking the progress of the reaction and completing the reaction.

[Effect]

The present invention was completed based on the discovery that the presence of sulfite or sulfite significantly increases the reaction rate in the esterification reaction of polyglycerin and fatty acid ester in the presence of an alkali, although the reaction mechanism is not clear. be.

180 where the esterification reaction takes place between the raw materials and the reaction product
However, the present invention, which significantly increases the reaction rate, shortens the time to maintain the raw materials and reaction products at high temperatures, and the process of maintaining the product at temperatures between The reaction is completed and a high-quality product that does not require any subsequent purification steps can be obtained.

〔Example〕

The present invention will be specifically explained using Examples and Comparative Examples.

In addition, % means weight %.

Example 1 1158 g of colorless and transparent polyglycerin (average degree of polymerization 6, hydroxyl value 970) obtained by polymerizing pharmacopoeial glycerin
(2.5 mol) was placed in a four-loaf flask equipped with a nitrogen inlet tube, a thermometer, a temperature controller, a water separation tube with a reflux tube, and a stirrer, and after raising the temperature to 80℃, palmitic acid (purity 98 %) 673 g (2.6 mol) were added to melt the palmitic acid. Next, 6 g of sodium hydroxide (reagent grade) and 3 g of sodium bisulfite (special grade reagent) were added, and the mixture was stirred at the same temperature for 30 minutes. Next, when the temperature was gradually raised, distillation of produced water accompanying the esterification reaction was observed from 180°C. After reaching 220°C, the reaction was continued at that temperature for 1 hour, and the reaction system became almost transparent, with an acid value of 0.9. The reaction was continued for an additional 30 minutes, and in a total of 1.5 hours, the reaction system became completely transparent and the acid value decreased to 0.28. Since the calculated amount of produced water was also confirmed, the reaction was terminated and 12
The reaction product was left to cool to 0°C and taken out, and 1754g (
A polyglycerol fatty acid ester was obtained with a yield of 98.8%.

This ester has a hue (Gardner) of 2, a saponification value of 84,
The hydroxyl value was 470, the main component was hexaglycerin monopalmitic acid ester, and there was almost no odor when melted. Furthermore, when I put the molten product (80°C) and the 0.3% aqueous solution on my tongue, I could not feel any bitterness in either case.

Example 2 Synthetic polyglycerin (PGLO4 manufactured by Daicel: tetraglycerin, hydroxyl value 1021021) 495.5 mol) was placed in the same four-loaf flask as in Example 1, heated to 80°C, and stearic acid ( purity 97%) 12
4.5 g of sodium carbonate (reagent grade) and 2.5 g of sodium bisulfite (special grade reagent) were added and stirred at 80° C. for 1 hour. After that, the temperature was raised to perform an esterification reaction at 230°C, and 1
The acid value after hours was 1.2. The acid value after another 1 hour, a total of 2 hours, was 0.31, so the reaction was terminated and 15
It was cooled to 0°C and the reaction product was taken out.

The yield of the obtained polyglycerol fatty acid ester was 163
7g (yield 96.5%), hue (Gardner) of 2, saponification value of 165, and hydroxyl value of 151, and the main component was tetraglycerol tristearate. This ester was evaluated for odor and bitterness in the same manner as in Example 1, but neither was detected.

Example 3 1404 g (3 mol) of synthetic polyglycerin (PGCO6 manufactured by Daicel; hexaglycerin, hydroxyl value 959) was placed in the same four-loaf flask as in Example 1, and the temperature was raised to 60°C to obtain oleic acid (purity 75%). 903g (3.2 moles)
Next, add 4.5 g of sodium carbonate (reagent grade) and 1.5 g of sodium bisulfite (special grade reagent),
The esterification reaction was carried out at 10°C. After 1 hour of reaction, the acid value became 1.8, and the reaction system became quite transparent, but not completely. When the reaction was continued for another 1 hour, the acid value became 0.89 and the reaction system also became transparent, so it was cooled and the reaction product was taken out at 100°C.

The yield was 2238 g (yield 99%), hue (Gardner) 3, saponification value 85, hydroxyl value 471, and hexaglycerol monooleate was the main component. This ester had a slight odor of oleic acid, but almost no bitterness was observed.

Example 4 698 g of polyglycerin used in Example 1 (1,5
mol) in the same four-loaf flask as in Example 1, and heated to 70°C.
Then, 1026 g (4.5 mol) of myristic acid (purity 98%) was added and melted. Next, 1.5 g of sodium hydroxide (reagent grade) and 2.5 g of sodium carbonate (reagent grade)
, 1.5 g of sodium bisulfite (reagent grade) and 1.0 g of sodium bisulfite (reagent grade) were added, and the mixture was maintained at the same temperature for 1 hour. Next, the temperature was raised to 225°C for 0.5 hours, the acid value was 0.9, and when the reaction was further continued for 0.5 hours, the acid value was 0.18, and the reaction system became completely transparent, so the temperature was increased to 225°C. The reaction product was taken out after cooling to . Yield: 1598g (yield 97.3%), Hue (Gardner)
2. The saponification value was 148, the hydroxyl value was 234, and hexaglycerin trimyristate was the main component. This ester had no odor, but a faint bitter taste was observed.

Comparative Example 1 A polyglycerin fatty acid ester was obtained in the same manner as in Example 1 except that sodium hydrogen sulfite was not added. In this case, the esterification reaction was carried out at 220°C, but the reaction system remained cloudy even 2 hours after the temperature was raised, and after 3 hours, it became slightly transparent with an acid value of 2.8, and the reaction was continued. After 5 hours, the acid value became completely transparent with an acid value of 0.51, and the produced water distilled out of the reaction system was close to the calculated value, so the reaction was terminated, and the reaction product was cooled to 120°C. I took it out. The yield was 1751 g (yield 98.6%), hue (Gardner) 5, saponification value 87, hydroxyl value 479, and the main component was hexaglycerin monopalmitate ester.

This ester has a burnt odor when melted, and has no odor when melted.
．． All of the 3% aqueous solutions had a strong bitter taste.

Comparative Example 2 1401 g of the synthetic polyglycerin used in Example 3 (
3 mol) was placed in the four-loop flask used in Example 1, and 8
The temperature was raised to 0°C, and 819 g of palmitic acid used in Example 3.
After adding (3.2 mol) and melting, 6.6 g of sodium hydrogen sulfite (reagent grade) was added, and after 1 hour, the mixture was stirred at the same temperature, and the temperature was raised to 220°C to perform an esterification reaction. After 1 hour, the reaction system turned brown and remained cloudy.

The reaction was further continued, and the same condition continued even after 5 hours, so the reaction was stopped. The reaction rate calculated from the amount of distilled water was 47%.

The above results are summarized in Table 1.

In Table 1, *1 indicates odor at 120°C, ○ indicates no odor,
Δ indicates a slight odor, × indicates an odor.

*2 indicates the bitterness of the produced ester when it is dissolved and placed on the tongue as a 0.3% aqueous solution, where ○ indicates no bitterness, △ indicates a little bitterness, and × indicates strong bitterness.

*3 is the reaction rate calculated from the distillate = 47%.

〔Effect of the invention〕

By the method of the present invention, the reaction rate can be increased and the esterification reaction is completed in a short time, so that a polyglycerol fatty acid ester with excellent color, almost no odor, and no bitterness can be obtained, and the purification after the reaction It has the advantage of not requiring

Table 1 f-cut v5 valve seven Suzuki Sadako

Claims (1)

[Claims] A method for producing polyglycerin fatty acid ester, which comprises esterifying polyglycerin and fatty acid using an alkali catalyst in the presence of sulfite or sulfite.