JPH02129196A - Production of powdery sucrose ester of fatty acid - Google Patents

Abstract

PURPOSE:To industrially and advantageously obtain the subject product without using an organic solvent by regulating a reaction mixture, containing sucrose ester of a fatty acid and unreacted substances and prepared by an aqueous medium method to a neutral pH, adding a neutral salt thereto, washing the formed precipitates with acidic water, repeating the above-mentioned operation, neutralizing the washed precipitates and spray-drying the neutralized precipitates. CONSTITUTION:A synthetic reaction mixture of a sucrose ester of a fatty acid, containing the sucrose ester of the fatty acid which is the objective substance and further unreacted saccharide, unreacted methyl ester of the fatty acid, catalyst, soap and the fatty acid and prepared by an aqueous medium method is regulated within a neutral region, preferably pH6.2-8.2 and preferably heated to 50-80 deg.C. A neutral salt is then added and the formed precipitates are subsequently washed with acidic water. The above-mentioned operation is repeated and the washed precipitates are neutralized and spray-dried to afford the objective ester. Furthermore, an acid used for regulating the pH is preferably lactic, acetic, hydrochloric or sulfuric acid.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to an industrial method for producing powdered sucrose fatty acid ester. More specifically, the present invention provides S obtained by aqueous method synthesis.
This invention relates to a technique for economically obtaining powdered sucrose fatty acid ester by purifying the E reaction mixture using water and by spray drying.

[Conventional technology]

(Background) Currently, sucrose fatty acid esters (
Hereinafter also referred to as << S E ))), industrially, sucrose and C8 to C22 higher fatty acid methyl ester are combined in a solvent (dimethylformamide, dimethyl sulfoxide, etc.).
(Solvent method: Japanese Patent Publication No. 1973)
-13102) or by making sucrose into a molten mixture with fatty acid soap using water without using a solvent, and then reacting it with higher fatty acid methyl ester in the presence of a catalyst (Mizunu method:
Japanese Patent Publication No. 51-14495). However, with either of these two synthetic methods, the reaction mixture contains, in addition to the target SE, contaminants such as unreacted sugars, unreacted fatty acid methyl esters, residual catalysts, soaps, and free fatty acids. Among these impurities, impurities that exceed the specified amount must be removed before becoming a product. In particular, the former solvent method requires complicated steps to remove high-temperature polar solvents such as DMF, whose regulations have become particularly strict in recent years. On the other hand, according to the latter aqueous method, there is no fear that the reaction solvent will be mixed into the reaction mixture, but since it contains a large amount of impurities, a large amount of organic solvent (hereinafter referred to as However, the use of solvents for purification brings about many industrial disadvantages as described below. α) Risk of explosion and fire. - Explosion-proofing of electrical equipment in preparation for 7-■. (3) Prepare for ■ above! Sealing the tJ manufacturing equipment. ■ The entire building will be made into a fire-resistant structure in preparation for ■ above. (Increase in fixed costs due to ■, ■, (2+) above Φ. ・'O) Increase in cost due to wear and tear of solvent. ■ Negative effects due to residual solvent remaining in product SE. ■) Negative effects on the health of employees, and furthermore, an increase in the number and cost due to an increase in Schiffl to prevent this.The disadvantages caused by the use of these solvents are particularly important for the industrial production of SE. This poses a particularly serious problem when S
The development of a purification technique that makes the use of purification solvents unnecessary during E purification is a pressing need in the industry. (Problems with the prior art) Therefore, purification methods that do not use solvents have been studied for some time.For example, (1) SH precipitation method using an acidic aqueous solution (British Patent No. 80
9,815 (1959)) (2)-A method of precipitation of SH using a neutral salt aqueous solution of the shell (Japanese Patent Publication No. 42-8950) is known. In addition to the above purification, since water is used as a purification solvent, the necessary SE is obtained as a hydrated product, so in order to make purification with water industrially possible, it is necessary to further
drying methods shall be taken into consideration. That is, the water-containing SE to be dried here is normally in the form of an aqueous solution if it has a water content of 80% or more, and in the form of a slurry if it has a water content of less than 80%. The viscosity of these SH hydrates generally increases rapidly from around 40°C and reaches the highest value around 50°C, but when the same temperature exceeds 50°C, the viscosity decreases rapidly, which is a very unique viscosity behavior. (Published by Applicant Company (Sugar Ester Story), p. 108) Therefore, attempts to simply evaporate water by heating under vacuum are virtually impossible due to the significant foaming property. At the end of water evaporation, SH has a low softening point or melting point (for example, the softening point of sucrose monostearate is around 52°C, and the melting point of distearate is around 110°C). , SE itself has a tendency to retain residual water, which makes dehydration more difficult. If the temperature during heating is high and the contact time with the heat transfer body is long, SE itself will decompose, causing not only strong coloring and caramelization but also 5 decomposition!
The acid value also increases due to M fatty acids (Special Publications Publication No. 1973-
9968). In addition, the latent heat of vaporization of water is unusually high compared to the solvent (
500Kcal/Kg-120 or more) and the high evaporation temperature are also factors that make drying difficult. Therefore, even when using a so-called flash dryer, which heats the slurry and continuously supplies it to a vacuum chamber and discharges it, as another type of drying method, for example, the large latent heat of water makes it difficult to dry the slurry sufficiently. Dehydration and drying are fraught with various difficulties, and even if these difficulties can be overcome, the SE after being dehydrated and dried under vacuum is in a molten state, so the melting point cannot be determined after taking it out of the dryer. It requires many steps, including cooling by blowing cold air, solidifying, and finally pulverizing in a pulverizer, and the final pulverizing step is accompanied by concerns about dust explosions. Therefore, solving the various problems associated with drying as described above is an important step in realizing the Kokunu process.

[The problem that the invention aims to solve]

In view of the above circumstances, the present invention provides a method for purifying crude SE synthesized by an aqueous medium method, regardless of whether a purification solvent is used or not.
In other words, the aim is to solve all the problems caused by the use of solvents by developing a drying method that does not cause quality deterioration during the drying process (even if water is used as the only solvent for purification). do. (Concept of the Invention) Therefore, the present inventor has developed a large number of SE stars with the aim of (a) minimizing SE stars dissolved in the aqueous phase, and (b) separating unreacted sugar from SE while avoiding decomposition of the unreacted sugar. As a result of conducting a salting-out experiment, it was found that when a neutral salt having a degree of C above a certain concentration is dissolved in an aqueous solution of a reaction mixture, a large proportion of SE precipitates. Therefore, by taking advantage of this phenomenon and repeating the precipitation operation with a neutral salt aqueous solution after dissolving the precipitated SE in water, the neutral salt accompanying the precipitated SH can be used to dissolve the precipitate into an appropriate amount. By washing with pH acidic water, a purified SE slurry is obtained which is substantially removed; and by spray drying this SE slurry, powdered SE can be obtained without any loss of quality. It has become clear that continuous production is possible. (Summary) In order to achieve the above object, the method for producing powdered sucrose fatty acid ester according to the present invention includes, in addition to the target sucrose fatty acid ester, unreacted sugar, unreacted fatty acid methyl ester, catalyst, The aqueous method sucrose fatty acid ester synthesis reaction mixture containing soap and fatty acids is adjusted to a pH in the neutral range, water and neutral salts are added, and the precipitate formed is washed with acidic water. The method is characterized by repeating neutralization and then spray drying. (Aqueous medium method SE synthesis reaction All inclusions SE production method by aqueous method synthesis involves making sucrose into a molten mixture with fatty acid soap in the presence of water, and then reacting it with higher fatty acid methyl ester in the presence of a catalyst. (Japanese Patent Publication No. 51-14495, etc.), which has the advantage that the reaction mixture contains more soap than the mixture obtained by solvent synthesis, but does not contain any residual reaction solvent. The SEE reaction mixture synthesized by the water-based method generally has a composition in the following range: Sucrose fatty acid ester = 15-74% unreacted sugar
= 1.0-80% unreacted fatty acid methyl ester = 0.5-10% neutral salt derived from potassium carbonate
= 0.05-7% stone floor 810
~50% fatty acids = 0.5~IO%
At this time, the ester distribution of SE is monoester lO ~
75% (diester or higher is 90-25z). The fatty acid roots mainly contained in each of fatty acid methyl ester, soap, and fatty acid are saturated and have a common carbon number of 016 to C27. (Addition of water) Next, water was added to the above reaction mixture, water: reaction mixture = 5: 1 to 40: 1 (weight ratio)... (1
), more preferably water:reaction mixture = 2o:I (!1f quantity ratio)......(2), and the pH is adjusted to 6.2 to 6.2. 8.2, preferably pH 7.5. In this case, the water addition ratio is outside the above range, e.g.
If the ratio of water to reaction mixture is less than 5, the resulting aqueous solution will have a high viscosity, making subsequent operations substantially difficult. Conversely, the quantitative ratio of water and reaction mixture is 40.
．． If too much water is added to the extent that a tlfI reaction occurs, the viscosity decreases and subsequent operations become easier, but on the other hand, a large amount of energy is required to remove water when recovering unreacted sugars, etc. This reduces economic efficiency. Furthermore, the pH of the aqueous solution is preferably adjusted between pH 6.2 and 8.2 in order to avoid decomposition of the target SE. At a hydrogen ion concentration of pH 6.2 or higher, quantitative alkali-based There is a risk of SE decomposition, and even in a weakly acidic range of pHEi of 2 or less, there is a risk of acid decomposition if exposed to high temperatures of 80° C. or higher, for example. (11! Analysis) The aqueous solution of the SEE reaction mixture adjusted to pH 3 as described above is maintained at 50 to 80°C as much as possible, and a neutral salt is further added. In this case, the amount of SH dissolved in water varies depending on the size of the neutral salt, but it is as shown in Table 1, regardless of the type of neutral salt. (Left below) Table 1 In Salt Table 1, weight of SE dissolved in the aqueous phase R=Y [gl, weight of precipitated SH=X [g] Total SE (X-Y) [Ratio of ffi amount of SE dissolved in the aqueous phase to gl = φ [%], then φ is defined by the following formula (3). φ=X100 (X) ・・・・・・・・・
...(3)
% Ester distribution Monoester = 70% Diester or higher = 30% Thus, the present inventors heated an aqueous solution containing a SH precipitate obtained by adding a neutral salt of 6% or more concentration to 50 to 80 °C. It was found that upon warming, a large proportion of SE precipitates. This phenomenon is unique and has important value for the purpose of the invention. As shown in Table 1, a large proportion of SE can be precipitated by adding neutral salts that can maximize the amount of SH precipitated, and by filtering or centrifuging the precipitated SE. It is possible to completely separate impurities dissolved in the aqueous phase. (Washing) After the above salting-out operation, pH-3.0 to 5.5. temperature 10
The separated SE cake described above is washed using acidic water whose temperature is adjusted to about 40°C. The acids used here include mineral acids such as kiX acid and sulfuric acid, and edible organic acids such as acetic acid and lactic acid, but are not limited to those listed separately. By washing under these conditions, impurities are removed.
It can be transferred to the aqueous phase side. During the above cleaning operation, if the temperature of the acidic water exceeds 40°C, if the operation lasts for a long time, for example, several months,
Not only is there a concern about acid decomposition of SE, but also the viscosity increases, making operation difficult. On the other hand, maintaining a low temperature of 10° C. or less requires a refrigerator that is not economical. Therefore, it is usually preferable to operate at 10 to 40°C, particularly around room temperature. In addition, when washing the SE cake with this acidic water, 1
Since it is necessary to remove from the SE cake as much as possible the unreacted sugars contained in the cake, the added neutral salts, and the king of salts produced by neutralization of the catalyst, the SE cake is
It is desirable that the particles be shredded to the smallest possible particle size in the acidic water. For example, this can be efficiently achieved using a fragmentation device with the trade name (Mycolloider))), and unreacted sugars, salts derived from catalysts, and three substances are separated from a cake with a total ratio of FR5E in an acidic aqueous phase. to move to. However, although it is said to be a substantially small amount, it is inevitable that some SE will elute into the acidic aqueous phase. Therefore, it can be reduced by relatively increasing the diester or triester content. The above-mentioned washing of the SE cake with acidic water becomes more complete by increasing the number of washings and increasing the amount of washing water, thus making it possible to obtain purified SE that is virtually pure. (Slurry concentration) This precipitated SE cake is slurry-like,
As it is, the pH is biased toward the acidic side, so the slurry whose pH is adjusted to around neutrality does not contain unreacted sugars, salts originating from the catalyst, and neutral salts added during salting out. , SE, including unreacted fatty acid methyl ester, soap and fatty acid surround, solids content 1-50%, moisture 99-99%
It is often in the 50% range. The amount of solids in this slurry is preferably about 40% or less for drying purposes, which will be described later.However, an excessively small amount of solids is undesirable from the viewpoint of energy costs for drying, and is usually , a value of 4% or more is economical. (Spray Drying) In the present invention, a spray drying method is particularly used for drying the SE slurry. The usefulness of this drying method is based on the fact that the present inventor has discovered from many experimental facts that SE
This is the best method for dehydrating and drying slurry. Incidentally, as mentioned above, even when using a normal vacuum dryer, typified by a so-called groove-type stirring dryer, slurry is continuously supplied, heated, and then released into a vacuum chamber. Even when a flash dryer is used, due to the viscosity characteristics and low melting point of SH, it is not possible to avoid quality deterioration phenomena such as an increase in the acid value, coloration, and caramelization of the SH to be treated. Furthermore, in the latter case, Naoko I! ! 5. The risk of explosion cannot be ignored. However, by employing the spray drying means discovered by the inventor, the drawbacks of the existing drying means can be solved at once. In the drying step in the present invention, the water-containing SE in a slurry state is
is continuously supplied to the spray drying tower via a pump, and is divided into fine atomized particles by atomization by a nozzle or centrifugal force of a rotating disk, and brought into contact with a drying air stream. This significantly increases the evaporation area of water, and therefore dehydration and drying can be completed within an extremely short time (within a few seconds after spraying). Note that as the atomizing means, it is desirable to use a one-rotation disk because the viscosity of the water-containing SH is high. (Spray drying means) The supply temperature of the SE solution or slurry can be arbitrarily changed between 40 and 80°C, but from the viewpoint of quality, it is preferably 40°C.
Choose a temperature within the range of 0-60°C. When the L solution or slurry is atomized by a rotating disk, for example, when the diameter of the disk is 5 to loc+++φ, it is 15.0
A rotational speed of 00 to 24.0 OOrp+s is suitable. The air blown into the tower should have at least the amount of heat required to evaporate the water in the solution or slurry; therefore, if the air temperature is low, a higher amount of air is required. It is. The air temperature at this time is 10~! Although the temperature may be in a wide range of 00°C, it is best to choose a temperature between 60 and 80°C in consideration of drying efficiency and prevention of thermal decomposition of the target SE. The humidity in the blown air is related to the drying efficiency as well as the air temperature.Although the absolute humidity suitable for the work is within a general range, it is particularly economical to have it within the range of . When the solid content concentration in the slurry sent to the spray drying tower exceeds 40%, the viscosity increases significantly, and as a result, the particle size of the sprayed slurry becomes relatively large, which slows down the drying of the water. As a result, it tends to adhere to the inner wall of the drying tower. Therefore, it is better to adjust the solid content concentration in the slurry to 40% or less. If the solid content concentration of the slurry is 40% or less, the diameter of the sprayed droplets will be smaller than if it exceeds 40%.
Since it becomes easier to dry, there is no fear of it adhering to the inner wall of the drying tower. However, if the solid content concentration of the slurry is 1, for example, 3%
Drying becomes easier when the size is smaller, such as less than 1,000 yen, but it is uneconomical in terms of the energy required. Therefore, the concentration of slurry supplied to the spray drying tower is 4.
A range of % to 40% is suitable. Conditions such as the required volume, required tower length, and required height of the spray drying tower are designed on the premise of the above spray conditions. If the tower design and operating conditions are suitable, powdered dry SE with less than 5% water content is continuously discharged from the bottom of the spray drying tower. The resulting product has a short thermal history and is of excellent quality, and requires almost no drying personnel. (Margin below)

[Effect]

Add acid to the SE-generating reaction mixture containing unreacted sugar, unreacted fatty acid methyl ester catalyst, soap, and fatty acid, adjust the pH to a neutral range, add water, and neutral salt, and heat at an appropriate temperature. When salted out, SE, unreacted fatty acid methyl ester, soap and fatty acid precipitate. Next, by washing this precipitate with acidic water, impurities such as unreacted sugars contaminating the precipitate, added neutral salts, and salts produced as by-products due to neutralization of the catalyst are removed and purified. This becomes a slurry of SH. By spray-drying this purified slurry, powdered SE with a moisture content of 5% or less is obtained.
is produced continuously.

【Example】

Hereinafter, the embodiments and effects of the invention will be explained with reference to Examples, but the examples are of course for explanation and are not meant to illustrate the limitations or limitations of the idea of the invention. (Left space below) Actual AJ 1 1 After the reaction solvent was distilled off from the aqueous method SE reaction mixture represented by the composition in Table 2, the residual liquid was neutralized with dairy milk. 2.000 g of water was added to 100 g of the dried material to dissolve it. To this aqueous solution, 100 g of monosalt was added, heated to 80° C., and the precipitated cake was filtered to obtain a cake. In addition, only a small amount of SE was contained in the e-liquid. 8') 2.00
When 0 g was added, SE was immediately precipitated as a white precipitate. Next, an acidic aqueous solution (p) containing this precipitate! 3.8)
After thoroughly stirring the mixture using a homomixer (described above), the precipitate was removed. This precipitate was rewashed twice by adding vinegar and water, and the pH was adjusted to 7.5 with caustic soda. The precipitate contained 32% solids, and the dry matter was as shown in the table below. It had a composition of -3. The washing liquid (i!! liquid) contained a small amount of SE.Rotating disk (disk) diameter: 10cmφ disk rotation speed 21
．． 000 rpm, air temperature, 55° C. This slurry was supplied to a spray drying tower while being maintained at 60° C., and was spray-dried. is the diameter of the spray drying tower: 2. Omφ Length of straight cylinder part: 1.5m Pyro 7 Met under dry conditions. The powdered SE obtained from the bottom of the spray drying tower has a moisture content of 2.
1%, bulk specific gravity 0.46, no coloring due to overheating, and good fluidity. Drying continued stably, and there were no problems such as powder adhesion to the internal walls of the spray drying tower, which was initially a concern. Furthermore, the monoester content during SE was 61% before and after drying.
There was no change at all, and there was also no change in the acid value. Example-2 Obtained in Example-1. While maintaining a precipitation cake (slurry) with a solid content of 32.0% at a temperature of 55°C, the inlet air temperature was 60°C and the slurry feeding rate was 0.8 kg/
Spray drying was performed in the same manner as in the spin-down process, except that the time was changed. The obtained SE grain powder had a water content of 1.8%, a bulk specific gravity of 0.41, good fluidity, and no coloration due to overheating. The amount of monoester in SH was 61.0%, which remained unchanged before and after drying, and the same was true for the acid value. Furthermore, no SE grain powder was observed to adhere to the inner wall of the spray drying tower.

【Effect of the invention】

As explained above, the present invention has developed a series of techniques for industrially producing purified SE in powder form from a reaction mixture for aqueous sucrose fatty acid ester synthesis without using any solvent. It has many effects such as: (+) It is possible to purify SH using only inexpensive water. (2) Since SH can be dried under normal pressure within a short period of time, there is no thermal deterioration of the product. (3) There is no need to worry about solvent explosion or fire, and therefore there is no need for expensive explosion-proof electrical equipment. (4) There is no concern that any solvent will be mixed into the product. (5) Improving the sanitary environment at @ba. (6) It can be industrialized at low cost. Patent applicant Daiichi Kogyo Seiyaku Co., Ltd.

Claims (1)

[Claims] 1. In addition to the target sucrose fatty acid ester, unreacted sugar,
The aqueous sucrose fatty acid ester synthesis reaction mixture containing unreacted fatty acid methyl ester, catalyst, soap, and fatty acid was adjusted to a pH in the neutral range, and the precipitate produced by adding a neutral salt was dissolved in acidic water. 1. A method for producing a powdered sucrose fatty acid ester, which comprises washing with water, repeating this operation to neutralize it, and then spray-drying it. 2 The composition of the reaction mixture is: Unreacted sucrose = 1.0-80.0% Unreacted fatty acid methyl ester = 0.5-10.0% Catalyst = 0.05-7.0% Soap = 1. The method according to claim 1, wherein: 0-80.0% fatty acid = 0.5-10.0% sucrose fatty acid ester = 15.0-95%. 3. The method according to claim 1, wherein the reaction mixture is adjusted to a pH of 6.2 to 8.2. 4. The method according to claim 1, wherein the reaction mixture after pH adjustment is heated to 50-80°C. 5. The method according to claim 1, wherein the weight ratio of water added to the reaction mixture and the reaction mixture is water:reaction mixture = 5:1 to 40:1. 6 The acid used to adjust the pH of the reaction mixture is lactic acid,
4. The method according to claim 1, wherein the acid is any acid selected from the group consisting of acetic acid, hydrochloric acid and sulfuric acid. 7 The fatty acid radical mainly contained in each of the fatty acid methyl ester, soap, and fatty acid in the reaction mixture has a carbon number of 1.
3. A method according to claim 1 or 2, having from 6 to 22 common saturated fatty acid roots. 8. The method according to claim 1, wherein the neutral salt added to the reaction mixture is any salt selected from the group consisting of common salt, mirabilite, potassium lactate, and potassium acetate. 9 Ester distribution of sucrose fatty acid ester is 10 to 75% as monoester content (diester or more is 90%
25%). 10. The method according to claim 1, wherein the acidic water has a pH value of 3.0 to 5.5. 11. Claim 1, wherein the temperature of the acidic water is 10 to 40°C.
or the method described in 10. 12. The method according to claim 1, wherein the slurry of the precipitate to be spray dried has a solids content of 4 to 40% and a water content of 96 to 60%. 13 The humidity and temperature of the blown air during spray drying are absolute humidity = 0.008 to 0.05 (kg・water/kg・dry air)
The method according to claim 1, wherein the temperature is in the range of 10.0 to 100.0°C. 14. The manufacturing method according to claim 1, wherein the composition of the powdered sucrose fatty acid ester of the product is within the following range. Moisture = 0.5-5.0% Unreacted fatty acid methyl ester = 0.5-10.0% Soap = 0.5-60.0% Fatty acid = 0.5-10.0% Sucrose fatty acid ester = 98 .0~15.0%