JPS5861192A - Fatty acid purification - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention The present invention relates to a method for refining fatty acids, and more specifically, to purifying crude fatty acids obtained by hydrolyzing fats and oils, or solid acids or liquid acids obtained by fractionating these fatty acids, to improve the color of the fatty acids. Method for obtaining highly purified fatty acids (Related).

The main impurities contained in crude fatty acids are: ■ undecomposed glycerides (mainly di- and monoglycerides), ■ oxygen-containing compounds (oxidation products containing hydroxyl and carbonyl groups), and ■ nitrogen derived from proteins. and sulfur compounds, ■phosphorus compounds derived from phospholipids.

Conventionally, the general "J
The distillation method that has been adopted for this purpose removes the impurities based on the boiling point difference between the fatty acid and the fatty acid, and by this method, it is possible to obtain a fatty acid with a good color and relatively high purity. However, in recent years, as the energy costs required for distillation operations have increased, improvements have been desired in terms of costs, and a solution to the problem of deterioration of fatty acids due to thermal denaturation during distillation has also been desired.

A number of fatty acid purification methods have been studied and proposed in place of the distillation method since ancient times. However, no method has been found that achieves the same purification effect as the distillation method by a single method, and there is no practical method for industrial use. For example, there is a method in which crude fatty acids are brought into contact with a solid adsorbent such as silicic acid gel or activated clay, and impurities are adsorbed and removed by this adsorbent.This method removes fatty acids and impurities. This method uses a solid adsorbent to adsorb and remove polar impurities by utilizing the difference in polarity between the Moreover, it was seriously lacking in industrial practicality, as it was accompanied by dangers in handling solvents.

In other words, when impurities are generally removed using a solid adsorbent such as silicic acid gel, activated clay, molecular sieve, or ion exchange resin, the removal effect largely depends on the movement speed of the adsorbed molecules, and this movement is A sufficient removal effect cannot be obtained if the dog is removed.

The rate of migration is related to the viscosity of the system; for example, a sufficiently low viscosity of about 1 to 2 centipoise or less at the adsorption treatment temperature will provide a sufficient rate of migration to be effective.

10,000, crude fatty acids are usually solid at room temperature (25℃).
Since it is a liquid of around 10 to 30 centipoise, in order to increase the movement speed of the impurities contained in it and increase the absorption and removal effect, it must be heated to over 100°C or dissolved or diluted with an organic solvent. The viscosity of the thread must be reduced to the above-mentioned level. However, the former heating method tends to cause desorption of impurities, which are adsorbed substances, from the solid adsorbent, and also causes problems such as deterioration of fatty acids due to the contact reaction of the adsorbent, so this method is not used. That's not appropriate.

In the end, I had no choice but to adopt the latter dilution method using an organic solvent.
In this case, a considerably large amount of organic solvent is required, causing the above-mentioned problem.

According to the findings of the present inventors, it was difficult to obtain commercially pure fatty acids even if such an organic solvent dilution method was used. For example, when crude fatty acids are diluted 10 times with n-hexane and then passed through a silicic acid gel column, extremely polar impurities are removed as stone, but less polar impurities such as undecomposed glycerides remain. do. Although the hue of the purified fatty acid obtained is better than that of the comparison, the purity of the fatty acid expressed as (neutralization value/saponification value) x 100 (%) is less than 99.0%, which is comparable to the distillation method. It was not possible to obtain purified fatty acids.

From the above-mentioned viewpoint, the present invention aims to achieve a purification effect equivalent to or better than that of distillation using another single method, without using any organic solvent, which is essential for purification methods using solid adsorbents. The object of the present invention is to provide an industrially useful method for refining fatty acids that can be obtained without causing the problems of thermal energy and thermal deterioration unlike distillation methods.

That is, this invention comprises a) a step of adding a crude fatty acid to an aqueous solution of urea or thiourea containing a surfactant to produce a urea adduct or a thiourea adduct of a fatty acid, and b)
A step of washing the adduct with a saturated aqueous solution of urea or thiourea containing a surfactant after separating the adduct, and C) decomposing the washed adduct to regenerate fatty acids. The present invention relates to a method for refining fatty acids characterized by the following.

In this way, the present invention takes advantage of the property of fatty acids and urea or thiourea to form adducts, generates adducts from crude fatty acids, and then separates the adducts to remove impurities that do not participate in adduct formation. This method uses a method of decomposing adducts and regenerating fatty acids. This method avoids the problems of thermal energy and thermal deterioration that occur in distillation methods, and allows highly efficient production of adducts using the single method of producing adducts. It becomes possible to obtain the purification effect of In addition, since the adduct is produced in an aqueous solution of urea or thiourea, problems caused by organic bath agents, which are unavoidable in the purification using the (2) adsorbent, do not occur.

By the way, there is a known method for purifying fatty acids that utilizes the production of adducts between fatty acids and urea or thiourea. In this method, crude fatty acids and dithiourea (such as urea) are heated and dissolved in an organic solvent and then cooled, and the adducts that precipitate out from the organic solvent solution are separated from the organic solvent solution and decomposed and regenerated. As is clear, such a method involves the use of a large amount of organic solvent, and therefore suffers from the same problems as when using a one-body adhesive.

On the other hand, in this invention, an adduct of fatty acid and urea or thiourea is produced in water, and in this point, there is an essential difference from the above-mentioned known method.

On the other hand, the production in daring water has the disadvantage of separating the produced adduct from impurities. That is, in an organic solvent system, since impurities are dissolved in the organic solvent, it is easy to separate the precipitated adduct from the impurity proboscis. However, in aqueous systems, fatty acids and impurities are both dispersed in the water, and adducts are formed under such conditions, so it is not easy to separate these adducts from impurities, and generally You can't avoid impurities from entering your body.

The inventors have discovered that the above problem can be solved by adding a surfactant to the urea or thiourea water bath film. In other words, if an adduct is generated after the crude fatty acid is sufficiently emulsified and dispersed with a surfactant, the entanglement of this adduct with impurities is prevented. By further washing the adducts separated from water with a saturated solution of raw wood or thiourea containing the same surfactant as mentioned above, it is possible to remove most of the impurities adhering to the surface of the adducts. It has been found that impurities can be substantially separated by this method.

In other words, the fatty acids decomposed and regenerated from the adducts from which impurities have been removed by the above method are completely comparable in properties to those obtained by distillation, have good hue, and have a purity of 99.0 coul% or more. It can be industrially advantageously used as refined fat Bjj and acid.

In step 3 of this invention, first, an aqueous solution of urea or thiourea containing a surfactant is prepared.

do. This water bath liquid is heated to a predetermined temperature, for example, about 50 to 80°C, and enough urea or thiourea is added to dissolve at this temperature. Generally fits 30-80 weights
It's a nine-hitter. In addition, the surfactant to be included may be any surfactant that has good reactivity toward crude fatty acids, and is usually a nonionic surfactant with a HLBIQ or higher, or a sulfate or sulfonic acid LJA type negative surfactant. Ionic surfactants are preferably used. The content of surfactant is
Usually 0.2-5% by weight, preferably 0.5-2.0% by weight
It is.

The crude fatty acid, preferably heated to the same temperature or close to it, is added to the above-mentioned heated aqueous solution and mixed with stirring. The amount of crude fatty acid added is 5 to 20% by weight, preferably 8 to 10% by weight, based on the aqueous solution. 'After addition, when the stirring is continued and the temperature is gradually cooled to a specified temperature, urea or thiourea precipitates in accordance with the saturated solubility, and at the same time, adducts with the fatty acids dispersed in the solution are formed. Generate and slurry. At this time, the surfactant contained in the water effectively prevents impurities from being mixed into the adduct.

In step b of the present invention, the adduct produced above is separated and then washed by dissolving urea or thiourea in saturated water containing a surfactant. This washing is repeated several times as necessary to remove impurities adhering to the adduct surface.

The use of interfacial viscosity agents is essential for the removal of the above impurities,
If this is not used, the cleaning effect cannot be obtained. The type and content of the surfactant are the same as in the three steps above.

The reason why the washing liquid used in step b is a saturated aqueous solution of urea or thiourea is to prevent destruction of the adduct.

Finally, in Step C, the adduct washed as described above is decomposed by heating to a temperature of about 60°C, for example, to regenerate fatty acids and separate them from black urea or thiourea. By washing the regenerated and separated fatty acids with hot water at about 60 to 80° C. and dehydrating them, a phased fatty acid product with a good color and high purity can be obtained.

Next, examples of the present invention will be described in more detail. In addition, in the following, part and % mean a rutted part and an overlapping %.

Example 1 Neutralization + [Ib 196.4, saponification value 201.2, fatty acid purity 97.6% - Hue Gardner - 11 beef tallow hydrolyzed crude fatty acids were heated to 60°C, and similarly 60'C1
In 1,000 parts of a urea water bath solution (containing 61% urea) containing 1% dodecyl sulfate (heated 1% dodecyl sulfate),
Added with stirring. After the addition was completed, the mixture was cooled to 25° C. over 1.5 hours while stirring was continued. At this point, the inside of the system became a slurry containing urea adducts of fatty acids.

After this urea adduct was separated, it was mixed with a saturated aqueous solution of urea at 25°C containing 1% dodecyl sulfate.
0 parts, stirred at 25°C for 30 minutes, and then distributed from door to door.

This operation was repeated again to thoroughly wash. Finally, the adduct was heated to 60° C. to regenerate fatty acids, separated from urea, and then washed with hot water at 70° C. Dehydrated it and it became 93.6
of purified fatty acids were obtained. This fatty acid has a neutralization value of 201.
8, saponification value 202.3, fatty acid purity 99.8%, hue AP) (A140 (Gardner 1).

In addition, when the above crude fatty acid is distilled by the usual method, it is 93.9
% of purified fatty acids are obtained, and its characteristics are as follows: neutralization value: 202.
2.Saponification value 203.0. The fatty acid purity was 99.6% and the hue was APHA160.

Reference Example 1 A fatty acid was obtained in the same manner as in Example 1, except that sodium dodecyl sulfate was not contained in the urea aqueous solution used for adduct production. This fatty acid had a Gardner 6 hue. This shows that the use of a surfactant in the adduct formation step is essential in this invention.

Example 2 Neutralization value 191.2, saponification value 200.8, fatty acid purity 9
5.2%, fractionated crude liquid acid of tallow crude fatty acid of hue Gardner 18 was heated to 55°C, and 1.5% heated to 70°C.
A urea aqueous solution containing polyoxyethylene (20 mol addition) octylphenyl ether (HLB=16) (
The mixture was added to 850 mg (containing 65% urea) with stirring.

Thereafter, in the same manner as in Example 1, 90.6 parts of purified liquid acid was obtained.

This mature acid has a neutralization value of 202.0 and a saponification value of 202.3.
, fatty acid purity 99.9% - hue APHA 200 (Gardner 1-2).

f: Oh, when the crude liquid ligneous acid is distilled using the normal method, the result is 90.
8 parts of purified liquid acid are obtained, the properties of which are: neutralization h + h
202.4, saponification value 203.5, fatty acid purity 99.5
%, and the hue was APHA250.

Reference Example 2 97.4 parts of fatty acid was obtained in the same manner as in Example 2, except that the adduct was not washed with a urea-saturated water bath solution containing a surfactant after being separated.

This fatty acid has a neutralization value of 193.3 and a saponification value of 201.2.
-Fatty acid line g96. x%, hue Gardner 12. From this, washing with a urea saturated aqueous solution containing a surfactant after producing the adduct is not recommended in this invention.
I know it's something missing.

Example 3 100 parts of hydrolyzed crude fatty acids of high oleic safflower oil with neutralization value 1 (12.5, saponification value 196.7, fatty acid purity 97.9%, hue Gardner 8) was humidified at 60°C and treated in the same way. Aqueous urea solution containing 0.5% sodium dodecylbenzenesulfonate (urea 6
1% (containing 1%) was added with stirring. below,
In the same manner as in Example 1, 92.6 parts of purified fatty acid was obtained. However, the surfactant included in the urea saturated water bath solution for cleaning was 0.5% sodium dotecylbenzenesulfonate. The obtained purified fatty acid had a neutralization value of i93.
1, saponification value 194.9, fatty acid purity 99.1%, and hue APRA 180 (Gardner 1).

In addition, when the crude fatty acid described in Wtj is distilled using the usual method.

92.9% purified fatty acid is obtained, and its characteristics are medium 4+
Monovalence 1'93.9, saponification value 195.3, fatty acid purity 9
The color was 9.3% and the hue was APHA2QQ.

Example 4 Neutralization value 197.0, saponification value 200.2 - fatty acid line U9
8.4%, hue Gardner 10 pork fat hydrolyzed crude fat ribs w
10 os was heated to 60°C and added to 1.00C of a thiourea aqueous solution containing 1% sodium dodecyl sulfate (containing 35% thiourea) heated to 60°C with stirring. Hereinafter, 93.2 parts of purified fatty acid was obtained using a trowel operating in the same manner as in Example 1.However, as a cleaning solution for the adduct separated by p, the split fatty acid had a neutralization value of 201. 1,
Saponification value 201.9, fatty acid purity 99.6%, hue AP
It was HA130 (Gardner 1).

In addition, if the crude fatty acid mentioned above is steamed using the conventional method.

93.8 parts of purified fatty acid was obtained, and its properties were as follows: neutralization value: 200.7, saponification value: 201.5, fatty acid purity: 99.6
9. The hue was APHA13Q.

Patent applicant: NOF Corporation

Claims (1)

[Scope of Claims] +1) a) Step of adding crude fatty acid to a water bath solution of urea or thiourea containing a surfactant to produce a urea adduct or thiourea adduct of a fatty acid, and l)) above. C) step of separating the adducts and washing them with a saturated aqueous solution of urea or thiourea containing a surfactant; and C) decomposing the washed adducts to produce fatty acids. Characteristic fatty acid purification method. (2) The surfactant used in step a and step C is an anionic surfactant or a nonionic surfactant with a HLBIQ of (') or higher. Purification method.