JPH0674237B2 - Method for producing propylene glycol monooleate - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing propylene glycol monooleate. In more detail, almost colorless, odorless,
And a method for producing propylene glycol monooleate having good stability.

[Conventional technology]

Propylene glycol monooleate is used as an emulsifier for foods, pharmaceuticals, cosmetics, etc., by dehydration reaction of oleic acid and propylene glycol at high temperature, or by adding propylene oxide to oleic acid in the presence of a catalyst. Manufactured.

[Problems to be solved by the invention]

However, conventional propylene glycol monooleate uses oleic acid that has not been sufficiently purified as a raw material, and the production method of the ester is not appropriate, so that the color and odor immediately after the production are bad, and moreover over time. Alternatively, there is a problem in that the color and odor become stronger by heating. In other words, conventional oleic acid uses distillation as the final step, but simple distillation alone not only causes impurities within the same boiling range as oleic acid, but also has many vapor pressure impurities in the oleic acid fraction. Therefore, the effect of separating impurities is insufficient. Further, since the distillation is carried out at a high temperature, decomposition of the oleic acid due to heat, deterioration of the substrate such as polymerization and isomerization, and a low boiling point component due to thermal decomposition of impurities are mixed in the oleic acid fraction. 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 be further colored and odorized when heated.

Propylene glycol monooleate is usually obtained by subjecting oleic acid and propylene glycol to a high temperature dehydration reaction in the presence or absence of a catalyst to distill the monoester from the reaction mixture or to add sodium hydroxide to oleic acid. Propylene oxide was added in the presence of a strong alkali such as potassium hydroxide or a Lewis acid catalyst such as boron trifluoride or aluminum chloride, and the monoester was distilled from the reaction mixture. However, these production methods have problems that the yield is low, the product is colored and has a strong odor, and that coloring and odor are strong 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 heat and oxidation stability and skin irritation (Japanese Patent Application No. 59-119170).

By adding propylene oxide to the oleic acid produced by this method in the presence of a specific catalyst, the present inventors obtained propylene glycol monooleate, which is almost colorless, odorless and stable, in a high yield. The inventors have found what is obtained and have reached the present invention.

The oleic acid used in the present invention is (a) a fatty acid mixture containing oleic acid and urea, which are dissolved in an organic solvent and then cooled to separate and remove precipitated crystals, and (b) a fatty acid contained in an organic solvent solution. Oleic acid is obtained by partially saponifying the mixture, recrystallizing the crystal, and subjecting the obtained crystal to acid decomposition.

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, the residual urea forms an acid salt of oleic acid and an adduct in an appropriate amount to form a hard and free-flowing crystal. The crystalline state is improved and the crystals obtained by recrystallization are easily filtered, 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 oil 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), methanol,
Lower alcohols such as 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 starting fatty acid, the target purity and yield, the setting of the number of crystallizations, etc., but is preferably 0.5 to 10 times by weight the starting fatty acid. If it is less than 0.5 times by weight, the separation effect will be lowered, and if it is more than 10 times by weight, the fatty acid concentration will be low and the production efficiency will be 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 contained in the raw material fatty acid and It is preferably 3 to 50 times by weight the total amount of the monounsaturated fatty acids higher than oleic acid. 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 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 and dissolved by heating, and then gradually cooled,
It is usually 30 ° C or lower, preferably 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, these crystals are removed by usual means such as filtration and centrifugation.

Normally, (a) step requires only one operation, but has 16 carbon atoms.
If the separation of the above saturated fatty acids or monounsaturated fatty acids higher than oleic acid is insufficient, the separation may be repeated.

In the step (b), first, lithium, sodium, potassium, and an organic solvent solution of the fatty acid mixture obtained in the step (a) are added.
Add a basic compound such as hydroxide or carbonate such as ammonia to partially neutralize. Oleic acid forms an acid salt by this partial saponification, and when cooled, the acid salt of oleic acid and a small amount of urea remaining in the step (a) form an adduct appropriately and become a crystal that is easily filtered as a whole,
It is easy to separate removed components such as polyunsaturated fatty acids.
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. If the neutralization rate is less than 20% of oleic acid, the yield of oleic acid obtained is low, and if it exceeds 60% of the total fatty acid mixture, the separation effect decreases and the crystalline state of the crystallized oleic acid acid salt deteriorates. It is difficult to filter 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. If it is higher than 10 ° C, the yield of oleic acid is lowered, and if it is lower than -30 ° C, the purity of oleic acid is lowered.

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 10
-50% by weight, and the cooling temperature is preferably 5-20 ° C.

The step (c) is a step of adding an acid to an acid salt of oleic acid to cause acid decomposition to obtain oleic acid.

Examples of the acid used for acid decomposition include 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 the 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 washing with water, emulsification during washing with water 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. The amount of the adsorbent used varies depending on the degree of purification of oleic acid and the target quality, but 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 propylene glycol monooleate, which comprises adding 0.9 to 1.1 mol of propylene oxide 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-
There are methylpiperidine, N-ethylpiperidine, N, N'-dimethylpiperazine, N, N'-diethylpiperazine and the like, and as the quaternary ammonium salt, tetramethylanimonium 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-ethylpyridinium halide, N-propylpyridinium halide, N-dodecylpyridinium halide, N-hexadecylpyridinium halide, N-benzylpyridinium halide, etc. There, where the halide is chloride, bromide, iodide, etc., tertiary amines or quaternary ammonium salts useful as catalysts for the addition reaction of the epoxy compound 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 reason that the reaction molar ratio of oleic acid and propylene oxide is limited is that the amount of unreacted oleic acid or diester is increased outside this range and the yield of propylene glycol monooleate is decreased. .

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. 40-150
The addition reaction of 0.9 to 1.1 mol of propylene oxide is carried out under conditions of a temperature of 50 ° C., preferably 50 to 110 ° C. and a pressure of 10 kg / cm ² G or less, preferably 5 kg / cm ² G or less. 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 obtained reaction mixture is distilled to remove the unreacted propylene oxide, and then to remove the catalyst, preferably dissolved in a water-incompatible solvent such as hexane, benzene, toluene, ethyl acetate and washed with water. , Activated carbon if necessary,
The desired propylene glycol monooleate can be obtained by treating with an adsorbent such as diatomaceous earth.

As a result, propylene glycol monooleate having a purity of 90% or more can be obtained, but distillation may be carried out to further increase the purity.

〔The invention's effect〕

According to the method of the present invention, it is possible to obtain propylene glycol monooleate which has almost no coloration and odor and is excellent in stability in a high yield.

〔Example〕

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

Example 1 12.5 kg of urea was added to 40 kg of methanol and dissolved by heating at 50 ° C.
10 kg of distilled oriental oil of Oreet Susaflower oil which had been heated was added and dissolved. Then, while stirring, the mixture was cooled to 10 ° C., the resulting crystals were centrifugally filtered, and 52 kg of filtrate (fatty acid content 6.
5 kg) was obtained. To this filtrate was added 5.8 kg of an aqueous solution containing 415 g of sodium hydroxide (45% equivalent of fatty acid contained) to dissolve it, and the mixture was stirred and cooled to -7 ° C and filtered to remove 4.3 kg of oleic acid acid salt crystals (acidic). A salt content of 3.7 kg) was obtained.
To this crystal was added 19 kg of an aqueous solution containing 930 g of phosphoric acid (1.5 equivalents of acid salt), and the mixture was heated to undergo acid decomposition. The obtained oil layer
After thoroughly washing with 0.5% citric acid aqueous solution, dehydration was performed 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 in a nitrogen gas atmosphere at 50 ° C. for 1 hour, and then filtered to give oleic acid (purity: 99.2%) 3.5 kg.
Got

Triethylamine was added to 564 g (2 mol) of the obtained oleic acid.
The mixture to which 2 g (0.022 mol) was added was placed in one autoclave, and after nitrogen gas replacement was performed, the mixture was heated to 90 ° C., resulting in 0.5 kg / cm ² G. Then, 116 g (2 mol) of propylene oxide was injected under pressure at 80 to 100 ° C under 5 kg / cm ² G for about 8 hours, and the reaction was continued at 90 ° C for 1 hour. Then, nitrogen gas was blown in to distill off unreacted propylene oxide, and the mixture was cooled to 50 ° C. The purity of propylene glycol monooleate immediately after the reaction was measured by gas chromatography and found to be 94%. To the reaction mixture was added 1 kg of warm water at 50 ° C, the pH was adjusted to 6.5 with phosphoric acid,
After stirring, the mixture was allowed to stand and the separated water was removed. Furthermore, 2
After washing with 1 kg of warm water each time, 1 g of activated carbon was added. After dehydration at 70 ° C. and 10 mmHg or less for 3 hours, activated carbon was filtered off to obtain 600 g of propylene glycol monooleate.

Comparative Example 1 1120 g (4 mol) of oleic acid prepared in Example 1 was mixed with 3 g
Add (0.02 mol) boron trifluoride ether, 232 g
(4 mol) propylene oxide at a reaction temperature of 40-60
It was added under the same conditions as in Example 1 except that the temperature was changed to ° C.
The reaction mixture was neutralized with 10% aqueous sodium hydroxide and then distilled to obtain 450 g of propylene glycol monooleate.

Comparative Example 2 Oleic acid obtained by fractionally distilling distilled fatty acids of Oleutx safflower oil in place of the oleic acid produced in Example 1 56
The reaction was carried out in the same manner as in Example 1 using 0 g to obtain 600 g of propylene glycol monooleate.

Test Example 1 With respect to each of the propylene glycol monooleates obtained in 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 a 200ml beaker,
Color, odor and peroxide number after heating for hours.

(3) Color, odor and peroxide value after taking 150 g of sample in a 300 ml beaker and leaving it in a thermostat at 50 ° C for 3 months.

The results of quality evaluation are shown in Table 1.

From Table 1, it can be seen that the propylene glycol 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 A mixture of 564 g (2 mol) of oleic acid prepared in Example 1 and 2 g (0.022 mol) of tetramethylammonium chloride was placed in one autoclave, nitrogen gas was replaced, and the mixture was heated to 90 ° C. to obtain 0.5. It reached to kg / cm ² G. Then, 116 g (2 mol) of propylene oxide was added to 80 to 100
The mixture was press-fitted for about 8 hours at a temperature of 5 ° C. and 5 kg / cm ² G or less, and the reaction was continued at 90 ° C. for 1 hour. Then, nitrogen gas was blown in to distill off unreacted propylene oxide, and the mixture was cooled to 50 ° C. The purity of propylene glycol monooleate immediately after the reaction was measured by gas chromatography and found to be 95%.

The reaction mixture was washed 3 times with 1 kg of warm water at 50 ° C., and 1 g of activated carbon was added. After dehydration at 70 ° C. and 10 mmHg or less for 3 hours, activated carbon was filtered off to obtain 620 g of propylene glycol monooleate.

Comparative Example 3 1.12 g (4 mol) of oleic acid prepared in Example 1
g (0.02 mol) of potassium hydroxide was added, and 232 g (4 mol) of propylene oxide was added under the same conditions as in Example 2. Since the content of propylene glycol monooleate immediately after the reaction was 35% by weight, potassium hydroxide was neutralized with phosphoric acid and then distilled to obtain 400 g of propylene glycol monooleate.

Comparative Example 4 Instead of the oleic acid produced in Example 1, 560 g of commercially available distilled oleic acid was used, and propylene oxide was added under the conditions shown in Example 2 to obtain propylene glycol monooleate. Since the purity immediately after the reaction was 94%, the same treatment as in Example 1 was carried out to obtain 615 g of propylene glycol monooleate.

Test Example 2 With respect to the propylene glycol 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 propylene glycol 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 total of 3 to 50 of (a) a fatty acid mixture containing oleic acid, a saturated fatty acid having 16 or more carbon atoms and a monounsaturated fatty acid higher than oleic acid contained in the fatty acid mixture. After dissolving the weight of urea and the organic solvent in an organic solvent and then cooling to separate and remove the precipitated crystals, (b) the fatty acid mixture contained in the organic solvent solution is partially saponified and then recrystallized to separate the crystals, (C) Addition of 0.9 to 1.1 mol of propylene oxide to 1 mol of oleic acid with oleic acid obtained by acid-decomposing the obtained crystals using a tertiary amine or a quaternary ammonium salt as a catalyst. A method for producing propylene glycol monooleate, which comprises: