JPH0641438B2 - Method for producing glycerin monooleate - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing glycerin monooleate. More specifically, it relates to a method for producing glycerin monooleate, which is almost colorless, odorless, and stable.

[Conventional technology]

Glycerin monooleate is used as an emulsifier for foods, pharmaceuticals, cosmetics and the like, and is produced by a dehydration reaction of oleic acid and glycerin at high temperature, or by adding glycidol to oleic acid in the presence of a catalyst.

[Problems to be solved by the invention]

However, conventional glycerin monooleate uses oleic acid that has not been sufficiently purified as a raw material, and the production method of the ester was not appropriate, so the color and odor immediately after the production were bad, and moreover, it was not heated over time. There were two problems, namely, the color and odor increased, and the purity of glycerin monooleate was low due to many by-products. That is, conventional oleic acid has a distillation as the final step, but not only impurities having the same boiling point range as oleic acid, but also many impurities having a vapor pressure to some extent in the oleic acid fraction are obtained by simple distillation. Since they are entrained, the effect of separating impurities is insufficient. Also,
Distillation is carried out at a high temperature, so degradation of the oleic acid due to heat, deterioration of the substrate such as polymerization, isomerization, etc., and thermal decomposition of impurities to generate low-boiling components, which are mixed in the oleic acid fraction, etc. As a result, the quality of oleic acid deteriorates, and only colored and odorous oleic acid can be obtained. Moreover, the obtained oleic acid tends to become more colored and odorous when heated.

Glycerin monooleate is usually obtained by subjecting oleic acid and glycerin to a high temperature dehydration reaction in the presence or absence of a catalyst, distilling a monoester from the reaction mixture, or adding potassium hydroxide or water to oleic acid. It is obtained by adding glycidol in the presence of a strong alkali such as sodium oxide or a Lewis acid catalyst such as boron trifluoride or aluminum chloride, and then distilling the monoester from the reaction mixture. However, in these production methods, the yield is low, the product is colored and has a strong odor, and the color and the odor become stronger with the passage of time or heating.

[Means for solving problems]

The applicant previously applied for a method for producing oleic acid, which is colorless and odorless and has excellent stability such as stability against heat and oxidation and skin irritation (Japanese Patent Application No. 59-119170).

By adding glycidol to the oleic acid produced by this method in the presence of a specific catalyst,
The present invention has been accomplished by finding that glycerin monooleate, which is almost colorless and odorless and has good stability, is obtained in high yield.

Oleic acid used in the present invention, (a) the fatty acid mixture containing oleic acid and urea are dissolved in an organic solvent and then cooled to remove the precipitated crystals, and (b) the fatty acid contained in the organic solvent solution. This is oleic acid obtained by partially saponifying the mixture, then recrystallizing the crystals, and (c) acid-decomposing the obtained crystals.

The step (a) is a step of removing higher saturated fatty acids having 16 or more carbon atoms and monounsaturated fatty acids higher than oleic acid from a fatty acid mixture containing oleic acid, and the resulting organic solvent solution inevitably contains a small amount. Urea remains. When the following step (b) is carried out using this organic solvent solution, residual urea forms an acid salt of oleic acid and an adduct in an appropriate amount to form a hard and free-flowing crystal, and therefore a partially saponified fatty acid mixture The crystalline state is improved and the crystals obtained by recrystallization become easier, and polyunsaturated fatty acids such as linoleic acid, monounsaturated fatty acids lower than oleic acid, lower saturated fatty acids and other impurities can be removed efficiently. As it can be carried out, highly pure and highly purified oleic acid is produced.

As the fatty acid mixture containing oleic acid used as this raw material, anything containing oleic acid can be used, and olive oil, sesame oil, rice bran oil, soybean oil,
Fatty acids obtained by hydrolyzing fats and oils such as tea seed oil, camellia oil, corn oil, rapeseed oil, balm oil, peanut oil, safflower oil, beef tallow, lard, chicken oil, sheep's fat and fish oil, and mixtures thereof. Can be used, and commercially available oleic acid containing impurities can also be used as a raw material. As a matter of course, the higher the content of oleic acid, the more efficiently the highly pure oleic acid can be obtained.

As the organic solvent used in the step (a), lower alcohols such as methanol, ethanol, n-propanol, and isopropanol, and mixed solvents containing these as the main components are used. The amount of the organic solvent used cannot be determined unconditionally depending on the composition of the raw material fatty acid, the target purity and yield, the setting of the number of crystallizations, etc., but is preferably 0.5 to 10 times the weight of the raw material fatty acid. If the amount is less than 0.5 times by weight, the separation effect is lowered, and if the amount is more than 10 times by weight, the fatty acid concentration is low and the production efficiency is lowered, which is disadvantageous.

The amount of urea used depends on the composition of the raw material fatty acid, the target purity and yield, the crystallization temperature, the amount of solvent, etc., but the saturated fatty acid having 16 or more carbon atoms and oleic acid contained in the raw material fatty acid. It is preferably 3 to 50 times by weight of the total amount of the higher monounsaturated fatty acids. If it is less than 3 times by weight, the removal of saturated fatty acids having 16 or more carbon atoms and monounsaturated fatty acids higher than oleic acid will be insufficient, and if it is more than 50 times by weight, the oleic acid yield will decrease.

In the step (a), a fatty acid mixture containing urea and oleic acid is added to an organic solvent, dissolved by heating, and then gradually cooled, usually at 30 ° C or lower, preferably in the range of 20 to -20 ° C. Saturated fatty acids having 16 or more carbon atoms, monounsaturated fatty acids higher than oleic acid, and the like form adducts with urea and are crystallized. Therefore, the crystals are separately removed by a usual means such as centrifugation.

Normally, (a) step is sufficient for one operation, but carbon number 1
It may be repeated if the separation of saturated fatty acids of 6 or more and monounsaturated fatty acids higher than oleic acid is insufficient.

In the step (b), first, a basic compound such as a hydroxide or carbonate such as lithium, sodium, potassium or ammonia is added to the organic solvent solution of the fatty acid mixture obtained in the step (b) to partially neutralize the solution. Harmonize Oleic acid forms an acid salt by this partial saponification, and when cooled, becomes an acid salt of oleic acid.
The small amount of urea remaining in the step (a) forms an adduct in a suitable amount to form a crystal that easily passes as a whole, and separation of components such as polyunsaturated fatty acids to be removed is easy. The neutralization rate in this case is from 20% of the oleic acid contained to 60% of the total fatty acid mixture, preferably 30% of the oleic acid.
% To 55% of the total fatty acid mixture. When the neutralization rate is less than 20% of oleic acid, the yield of oleic acid obtained is low, and when it exceeds 60% of the total fatty acid mixture, the separation effect is lowered and the crystalline state of the crystallized acid salt of oleic acid is deteriorated. And the purity of the obtained oleic acid decreases.

The temperature for cooling to crystallize the acid salt of oleic acid is 10 to -30 ° C, preferably 5 to -20 ° C. 1
If the temperature is higher than 0 ° C, the yield of oleic acid will decrease, and if it is lower than -30 ° C, the purity of oleic acid will decrease.

The crystals of the acid salt of oleic acid thus formed are separated from the solution containing the polyunsaturated fatty acid by a conventional method.

The crystal of the acid salt of oleic acid can be further improved in purity by repeating recrystallization.

As the solvent used for repeating the recrystallization of the acid salt of oleic acid, methanol, ethanol, isopropanol,
A polar solvent such as n-butanol, isobutanol, acetone, methyl ethyl ketone, diethyl ether, ethyl acetate or acetonitrile, or a mixed solvent containing these is used. In this case, the concentration of the acid salt of oleic acid is 1
0 to 50% by weight, and the cooling temperature is preferably 5 to -20 ° C.

In the step (c), an acid is added to an acid salt of oleic acid to decompose the acid,
This is a step of obtaining oleic acid.

As the acid used for acid decomposition, sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, phosphorous acid, hypophosphorous acid, carbonic acid, inorganic acids such as boric acid, acetic acid, oxalic acid, malonic acid, succinic acid, malic acid,
Organic acids such as tartaric acid and citric acid can be used. The amount of the acid used is equal to or more than the equivalent of the base forming the acid salt of oleic acid, and preferably 1.2 equivalent or more.

After acid decomposition, the acid used for acid decomposition remaining in oleic acid is removed by washing with water. When a small amount of polybasic acid such as oxalic acid or citric acid is added during the water washing, emulsification during the water washing can be prevented, and acid decomposition of the acid salt of oleic acid is also completely carried out.

In this way, high-purity oleic acid can be obtained, but in order to remove a trace amount of impurities, it is also possible to carry out an adsorbent treatment or distillation which is usually used for refining fatty acids.

As the adsorbent used for the adsorbent treatment, clay, activated clay,
Activated carbon, silica gel, alumina, silica-alumina, ion exchange resins, synthetic adsorbents and the like are available, and they are used alone or as a mixture. Although the amount of the adsorbent used varies depending on the degree of purification of oleic acid and the target quality, it is 0.1 to 5% by weight relative to oleic acid. The temperature of the adsorbent treatment is not less than the melting point of oleic acid, preferably 30 to 80 ° C. The processing time is about 20 minutes to 2 hours.

Distillation is performed under reduced pressure in an atmosphere of an inert gas under the conditions usually used for distillation of oleic acid. The vacuum should be as low as possible and the distillation temperature should be as low as possible.

That is, the present invention, in the oleic acid obtained by this method,
A method for producing glycerin monooleate, which comprises adding 0.9 to 1.1 mol of glycidol to 1 mol of oleic acid using a tertiary amine or quaternary ammonium salt as a catalyst.

As the tertiary amine used as a catalyst, triethylamine, tripropylamine, tributylamine, triisoamylamine, triethanolamine, pyridine, N-
Methylpiperidine, N-ethylpiperidine, N, N'-
There are dimethylpiperazine, N, N′-diethylpiperazine and the like, and as the quaternary ammonium salt, tetramethylammonium halide, tetraethylammonium halide, tetrapropylammonium halide, tetrabutylammonium halide, methyltriethylammonium halide, methyltripropylammonium halide. , Methyltributylammonium halide, ethyltrimethylammonium halide, ethyltripropylammonium halide, ethyltributylammonium halide, trimethylbenzylammonium halide, triethylbenzylammonium halide, tripropylbenzylammonium halide, tributylbenzylammonium halide, N-methylpyridinium halide, N -Ethylpyridy There are um halides, N-propylpyridinium halides, N-dodecylpyridinium halides, N-hexadecylpyridinium halides, N-benzylpyridinium halides, and the like, where the halides are chloride, bromide, iodide, etc., and are used for addition reaction of epoxy compounds. A catalytically effective tertiary amine or quaternary ammonium salt is used.

The oleic acid used in the present invention is limited to the oleic acid produced by a specific method, because the oleic acid has a high purity, is colorless and has no odor, and further has good stability and is colored during the reaction. This is because it produces almost no odor.

The charging ratio of oleic acid and glycidol is limited because the amount of unreacted oleic acid or by-products is increased outside this range, and the yield of glycerin monooleate decreases.

Next, the manufacturing method of the present invention will be specifically described.

First, 0.001 to 0.5 mol, preferably 0.003 to 0.05 mol of a catalyst is added to 1 mol of oleic acid, and the air in the space is replaced with an inert gas such as nitrogen gas. Then 40-1
50 ° C., preferably 50-110 ° C., pressure 10 kg / cm ²
0.9 to 1. under G or less, preferably 5 kg / cm ² G or less.
React with 1 mol of glycidol. In this case, if the amount of the catalyst is less than the above amount, the reaction does not proceed, and if it is too much, the removal becomes difficult, and coloring or odor is likely to occur. If the reaction temperature is lower than the above, the reaction rate is slow, and if it is too high, coloring or odor is likely to occur.

The reaction mixture obtained, after distilling off unreacted glycidol, to remove the catalyst, preferably dissolved in a solvent incompatible with water, such as hexane, benzene, toluene, ethyl acetate, washed with water, If desired, the target glycerin monooleate can be obtained by treating with an adsorbent such as activated carbon or diatomaceous earth.

As a result, glycerin monooleate having a purity of 90% or more can be obtained, but distillation may be performed to further increase the purity.

〔The invention's effect〕

According to the method of the present invention, glycerin monooleate having almost no coloration and odor and excellent stability can be obtained in good yield.

〔Example〕

 The present invention will be described with reference to Examples, Comparative Examples and Test Examples.

Example 1. After adding 12.5 kg of urea to 40 kg of methanol and heating and dissolving, 5
Oleyc safflower oil distilled fatty acid 10 heated to 0 ℃
kg was added and dissolved. Then, the mixture was cooled to 10 ° C. with stirring and the resulting crystals were centrifuged to obtain 52 kg of a liquid (fatty acid content of 6.5 kg). Sodium hydroxide 4
5.8 kg of aqueous solution containing 15 g (45% equivalent of fatty acid content)
Was added and dissolved, and the mixture was cooled to -7 ° C with stirring and separated.
kg) was obtained. 930 g of phosphoric acid (1.5 of acid salt)
1.9 kg of an aqueous solution containing double equivalent) was added, and the mixture was heated to be acid-decomposed. The obtained oil layer was thoroughly washed with a 0.5% aqueous citric acid solution and then dehydrated to obtain 3.6 kg of oleic acid. 18 g of activated carbon was added to the obtained oleic acid, and the mixture was stirred under a nitrogen gas atmosphere at 50 ° C. for 1 hour, and then filtered to obtain 3.5 kg of oleic acid (purity: 99.2%).

A mixture obtained by adding 2 g (0.022 mol) of triethylamine to 564 g (2 mol) of the obtained oleic acid was placed in one autoclave, the atmosphere was replaced with nitrogen gas, and the mixture was heated to 90 ° C., resulting in 0.5 kg / cm ² G. Then 148g (2
Mol) glycidol at 80-100 ° C, 5 kg / cm ² G
Press-fitting was performed under the following conditions for about 8 hours. 90 ° C
After continuing the reaction for 1 hour at 90 ° C under a nitrogen gas stream, 2 mm
Unreacted glycidol was distilled off below Hg. When the reaction mixture was taken out after cooling to room temperature and the purity of glycerin monooleate was measured by gas chromatography,
It was 95%.

After adjusting the pH to 6.5 by adding phosphoric acid to the reaction mixture, 1
Was dissolved in hexane, and washed 3 times with warm water 1 at 50 ° C., 1 g of activated carbon was added, and the temperature was raised to 70 ° C. Next 7
Remove volatile components at 0 ℃, 10mmHg or less over 5 hours,
The activated carbon was separated to obtain 630 g of glycerin monooleate (yield 90%).

Comparative Example 1. Example 1. Oleic acid produced in 1120 g (4 mol)
Example 3 except that 3 g (0.02 mol) of boron trifluoride ether was added to 296 g (4 mol) of glycidol and the reaction temperature was changed to 40 to 60 ° C. And added under the same conditions. After the reaction mixture was neutralized with a 10% aqueous sodium hydroxide solution, the purity of glycerin monooleate was measured to be 40%. Therefore, the mixture was distilled to obtain 500 g of glycerin monooleate (yield 35
%).

Comparative example 2. Example 1. In place of the oleic acid produced in Example 1, 560 g of oleic acid obtained by fractional distillation of oleic safflower oil-distilled fatty acid was used, and Example 1. React in the same way as
620 g of glycerin monooleate was obtained (yield 87
%).

Test Example 1. With respect to the obtained glycerin monooleate of Example 1, Comparative Example 1 and Comparative Example 2, quality evaluation of the following items was performed.

(1) Color, odor and peroxide value immediately after production.

(2) Take 150g of sample in 200ml beaker and
Color, odor and peroxide number after heating for 7 hours at 0 ° C.

(3) Take 150g of sample in a 300ml beaker and
Color, odor and peroxide value after standing for 3 months in an incubator at ℃.

The results of quality evaluation are shown in Table 1.

From Table 1, it can be seen that the glycerin monooleate obtained by the production method of the present invention has a good color and odor and is stable against heating and aging.

Example 2. Example 1. 2g (0.022mol) of tetramethylammonium chloride to 564g (2mol) of oleic acid prepared in
The mixture to which 1 was added was placed in 1 autoclave, the atmosphere was replaced with nitrogen gas, and then the mixture was heated to 90 ° C., resulting in 0.5 kg / cm ² G. Then add 148 g (2 moles) of glycidol.
Press-fitting was carried out for about 8 hours under the conditions of 0 to 100 ° C. and 5 kg / cm ² G or less. After continuing the reaction at 90 ° C for 1 hour,
Under a nitrogen gas stream, unreacted glycidol was distilled off at 90 ° C. and 2 mmHg or less. After cooling to room temperature, the reaction mixture was taken out and the purity of glycerin monooleate was measured by gas chromatography and found to be 93%.

The reaction mixture was dissolved in ethyl acetate (1), washed with warm water (1) at 50 ° C three times, and 1 g of activated carbon was added to the mixture (70 ° C).
The temperature was raised to. Volatile components were removed over 5 hours at 70 ° C. and 10 mmHg or less, and activated carbon was separated to obtain 615 g of glycerin monooleate. (Yield 86%) Comparative Example 3. Example 1. Oleic acid produced in 1120 g (4 mol)
1.12 g (0.02 mol) of potassium hydroxide was added to
g (4 mol) of glycidol was added under the same conditions as in Example 2. Immediately after the reaction, the purity of glycerin monooleate is 3
Since it was 0% by weight, potassium hydroxide was neutralized with phosphoric acid and then distilled to obtain 380 g of glycerin monooleate (yield 27%).

Comparative Example 4. Example 1. 560 g of distilled oleic acid obtained by simple distillation of commercially available undistilled oleic acid was used in place of the oleic acid produced in 1., and glycidol was added under the conditions shown in Example 2.
Glycerin monooleate was obtained. The purity immediately after the reaction is 92
%, It was treated in the same manner as in Example 1 to obtain 610 g of glycerin monooleate (yield 85%).

Test example 2. With respect to the glycerin monooleate obtained in Example 2, Comparative Example 3 and Comparative Example 4, quality evaluation of the same items as in Test Example 1 was performed. The results are shown in Table 2.

From Table 2, it can be seen that the glycerin monooleate obtained by the production method of the present invention has a good color and odor and is stable against heating and aging.

Claims (1)

[Claims] 1. A fatty acid mixture containing oleic acid and urea are dissolved in an organic solvent and then cooled to separate and separate the precipitated crystals, and the fatty acid mixture contained in the organic solvent solution is partially saponified and then recrystallized. The crystals are separated by the method described above, and 0.9 to 1.1 mol of glycidol is added to 1 mol of oleic acid by using a tertiary amine or a quaternary ammonium salt as a catalyst to the oleic acid obtained by the method of acid-decomposing the crystals. A method for producing glycerin monooleate characterized by the following.