JP2648936B2 - Method for producing sucrose fatty acid ester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a method for industrially refining powdered sucrose fatty acid esters. More specifically, the present invention relates to a technique for industrially purifying and pulverizing sucrose fatty acid esters in a reaction mixture for producing sucrose fatty acid esters by a solvent method.

[Prior art]

(Background) At present, sucrose fatty acid esters (hereinafter abbreviated as “SE”) useful as surfactants are commercially available from sucrose and C _{8 to} C _22.
With a higher fatty acid methyl ester in an organic solvent (dimethylformamide, dimethylsulfoxide, etc.) under an appropriate catalyst (solvent method: Japanese Patent Publication No. 35-13102), or by using water without using an organic solvent. After sucrose is made into a solvent mixture with a fatty acid soap, it is reacted with a higher fatty acid methyl ester in the presence of a catalyst (aqueous medium method: Japanese Patent Publication No. 51-1448).
No. 5). However, in any of these two synthetic methods, in addition to the target SE, unreacted sugar, unreacted fatty acid methyl ester, residual catalyst, soap,
It contains impurities such as free fatty acids and volatiles, and of these impurities, impurities whose content exceeds a specified amount must be removed before the product is formed. In particular, among the contaminants, the removal of the residual catalyst with the former solvent method (volatiles), the recently highly regulated, it is only crucial have become ^Note). Note: According to the US FDA standard, the amount of residual dimethyl sulfoxide allowed in SE is 2 ppm or less (Fed.Regist.,
51 (214), 40160-1). Therefore, conventionally, a large amount of an organic solvent (for example, butanol, toluene, methyl ethyl ketone, methyl acetate, etc .; for the purpose of removing the residual reaction solvent from the crude SE;
588, 48-10448, etc.), but the heavy use of such solvents has the following significant disadvantages to the industrial production of SE. Explosion, fire hazard. Explosion-proof electrical equipment provided above. Sealing of the production equipment provided above. The fire-resistant structure of the whole building prepared above. Above, due to rising fixed costs. Cost increase due to solvent wear. Negative effect due to residual solvent remaining in product SE. Adverse effects on the health of employees, resulting in an increase in the number of employees and an increase in fixed costs due to an increase in shifts to prevent them. Under such circumstances, development of a purification technique that makes the use of a purification solvent unnecessary in SE purification has been a pressing need in the art. (Problems of the prior art) Therefore, a purification method that does not use an organic solvent has been conventionally studied. For example, a typical method is as follows: (1) SE precipitation method using an acidic aqueous solution (UK Patent 809,81)
5 (1959)) (2) Precipitation method of SE with general neutral salt aqueous solution
−8850). However, as in method (1), for example, when an aqueous solution of hydrochloric acid is added to the reaction mixture, SE is immediately precipitated, but unreacted sucrose is easily decomposed and converted into glucose and fructose. (0-5 ° C.), decomposition cannot be avoided. This makes it difficult to recover and reuse unreacted sugar. Also, as in method (2), SE is immediately precipitated even when an aqueous solution of a neutral salt such as salt or sodium sulfate is added to the reaction mixture. In this case, the decomposition of unreacted sugar does not occur, but the monoester, which is a useful component in SE, is dissolved in the aqueous phase side, causing not only a large loss but also high HLB It is an obstacle when you want to get SE. According to a more recent Japanese Patent Application Laid-Open No. Sho 51-29417, a mixed solution of water and a "purified solvent" (which is particularly called to distinguish it from the reaction solvent) is composed of a light liquid layer (upper layer) and a heavy liquid layer (lower layer). The property of phase separation is used. That is, generally a heavy liquid layer (lower layer)
Contains a large amount of water, and hydrophilic unreacted sugar, catalyst-derived salts, and the like are dissolved in the heavy liquid layer (lower layer).
On the other hand, since the light liquid layer (upper layer) contains a large amount of purified solvent, small polar substances such as SE, fatty acids and unreacted fatty acid methyl esters are dissolved in this light liquid layer. However, reaction solvents such as dimethyl sulfoxide also dissolve in the lower heavy liquid layer, but unfortunately also dissolve in the upper light liquid layer, so it is not possible to completely decompose the reaction solvent by this method alone. It is. Therefore, a very large amount of a purified solvent is required only for removing a trace amount of the reaction solvent. As mentioned above, we have seen the problems of the existing technologies focusing on the removal of the reaction solvent. Purification of SE using only water as a solvent (water-based method purification)
An important consideration in connection with is the overcoming of the drying problems of purified hydrous SE. That is, since water is used as a solvent,
The SE is usually in the form of an aqueous solution when the water content is 80% or more, and in the form of slurry (slurry) when the water content is less than 80%. In general, these SE hydrates sharply increase in viscosity from around 40 ° C. and have the highest value around 50 ° C.
Exceeding the same temperature, it exhibits a very peculiar viscous behavior in which the viscosity drops sharply (see “Sugar Ester Story (1984)” published by the applicant company, p. 108). It is virtually impossible due to the remarkable foamability. And if the temperature at the time of heating is high and the contact time with the heating body is long, SE will decompose,
Not only causes strong coloring and caramelization, but also the acid value increases due to fatty acids released by decomposition (see Japanese Patent Publication No. 37-9966). In particular, at the end of moisture evaporation, SE has a low softening point or low melting point (for example, the softening point of sucrose monostearate is around 52 ° C, and the melting point of sucrose distearate is 110 ° C)
(Nearby), the SE itself tends to hydrate the remaining water, which makes dehydration extremely difficult. in addition,
The latent heat of vaporization of water is unusually high compared to solvents (500 kcal / kg
・ H ₂ O or more) and high evaporation temperature also contribute to the difficulty of drying. Therefore, for example, as another type of drying method, even when a so-called flash type dryer in which the slurry is heated and continuously supplied to and released from the vacuum chamber is used, sufficient dehydration due to the large latent heat of water is required. Although various difficulties are involved in drying, even if these difficulties can be overcome, the SE after being dehydrated and dried under vacuum is in a molten state. A number of steps are required to cool, solidify, and finally pulverize with a pulverizer by blowing cold air or the like down to the following, and there is a concern of dust explosion in the final pulverization step. Therefore, solving the above-mentioned problems associated with drying is also an important step for realizing the purification by the aqueous medium method.

[Problems to be solved by the invention]

In view of the above circumstances, the present invention provides a crude synthesized by a solvent method.
Develop industrial technology to remove residual solvents and other impurities from SE without using any purification solvent and without substantial loss of SE, and to dry and pulverize without deteriorating quality. To solve all problems caused by the use of solvents. (History of the invention) First, the inventor of the present invention first (a) SE dissolved in the aqueous phase side
The goal is to resolve the three issues of minimizing the amount, (b) avoiding the decomposition of unreacted sugar, and (c) dissolving the remaining reaction solvent into the aqueous phase to separate it from SE. As a result of many salting-out experiments, when neutral salts were dissolved in an aqueous solution of the reaction mixture, under a suitable combination of pH, temperature, neutral salt concentration and water amount, a large proportion of SE was observed.
Not only precipitates, but surprisingly, the aqueous solvent dissolves the reaction solvent in addition to the unreacted sugar. Therefore, by utilizing this phenomenon, it is possible to transfer the remaining volatile components (residual reaction solvent) substantially into the aqueous phase while minimizing the loss of SE, and to prevent the SE from being precipitated. The neutral salts that have been removed can be substantially removed by washing the precipitate with acidic water at an appropriate pH to purify the SE, and by further spray-drying the precipitate, the water content can be reduced without deterioration. % Or less can be dehydrated and powdered. (Summary) The present invention is based on the above discovery, and includes a reaction mixture containing unreacted sugar, unreacted fatty acid methyl ester, catalyst, soap, volatile matter, and fatty acid, in addition to a target sucrose fatty acid ester. The sucrose fatty acid ester of sucrose is characterized in that a precipitate formed by adjusting the pH to a neutral region and adding water and an aqueous salt is washed with acidic water, neutralized, and then spray-dried. The gist is a manufacturing method. Hereinafter, important matters relating to the invention will be described separately. (Synthesis of SE by Solvent Method) In the synthesis of SE by the solvent method, usually, a mixture of sucrose and fatty acid methyl ester is added and dissolved in a reaction solvent, for example, dimethyl sulfoxide in an amount several times the total amount of these. The reaction rate can be easily increased to 90% or more (based on fatty acid methyl ester) by maintaining at 80 to 90 ° C. for several hours in a vacuum of about 20 to 30 Torr in the presence of an alkaline catalyst such as potassium carbonate (K ₂ CO ₃ ). To purify the SE reaction mixture. Next, an organic acid such as lactic acid or acetic acid or a mineral acid such as hydrochloric acid or sulfuric acid is added to the SE reaction mixture in an equivalent amount in order to eliminate the activity of the alkaline catalyst in the SE reaction mixture. This neutralization converts the catalyst to the corresponding salt, such as potassium lactate. Finally, when the reaction solvent such as dimethyl sulfoxide is distilled off under vacuum, a mixture having the following composition range (a reaction mixture after neutralization and distillation) is obtained. Sucrose fatty acid ester = 15.0-92% Unreacted sugar = 1.0-80% Unreacted fatty acid methyl ester = 0.5-10% Catalyst derived neutral salt = 0.05-7% Soap = 1.0-10% Fatty acid = 0.5-10% Volatile content (residual reaction catalyst) = 5.0 to 30% At this time, the ester distribution of SE is 10 to 75% of monoester.
% (90 to 25% for diester or higher). The fatty acid roots mainly contained in each of the fatty acid methyl ester, the soap and the fatty acid are saturated and have a common C ₁₆ -C ₂₂ carbon number. (Hydration) Next, water is added to the above reaction mixture, and water: reaction mixture = 5: 1 to 40: 1 (weight ratio). Water: reaction mixture = 20: 1 (weight ratio) ... (2) Add to the ratio of the formula and adjust the pH to 6.2-8.2, preferably pH
7.5. In this case, when the addition ratio of water is out of the above range, for example, when the amount ratio of water to the reaction mixture is less than 5,
The viscosity of the obtained aqueous solution becomes large, and subsequent operations become substantially difficult. Conversely, the ratio of water to the reaction mixture is
If an excess of water is added so as to exceed 40, the viscosity becomes small and the subsequent operation becomes easy, and the desired reaction solvent is preferably removed. When recovering water, a great deal of energy cost is required for removing water, and economic efficiency is lost. In addition, the aqueous solution should be
It is preferably adjusted to a pH between 6.2 and 8.2. At a hydrogen ion concentration of pH 8.2 or higher, there is a concern that the decomposition of SE by an alkali may occur quantitatively, and even in a weakly acidic region of pH 6.2 or lower, for example, when exposed to a high temperature of 90 ° C or higher, acid decomposition may occur. There is fear. (Salt-out) The aqueous solution of the SE reaction mixture whose pH has been adjusted as described above is kept at 50 to 80 ° C as much as possible, and a neutral salt is further added. The present inventors have found that, based on the results of a number of experiments, when an aqueous solution containing a precipitate of SE obtained by adding a neutral salt is heated to 50 to 80 ° C. and heated, the amount of SE eluted into the aqueous phase is increased. Was found to be minimized, and even though the composition of volatiles (remaining reaction solvent) contained in the reaction mixture varied greatly from 3.0 to 30.0%, most of the SE was found to precipitate. . Such a phenomenon that SE is precipitated only by the addition of neutral salt and the volatile component shifts to the aqueous phase side is a unique phenomenon.At the same time, while using water, the loss of SE is kept to a minimum. This is important for the purpose of the invention of removing volatile components in the reaction mixture. Now, the weight of the SE dissolved in the aqueous phase side = Y [g] The weight of the precipitated SE = X [g] The total SE (X + Y) [g] is dissolved in the aqueous phase side
If the weight ratio of SE = φ [%], φ is defined by the following equation (1). Here, a sample reaction mixture (dry matter) having the following composition was dissolved in 20 times (weight ratio) water (pH 7.8) and heated to 75 ° C., and the fatty acid residue in the sample reaction mixture was the fatty acid residue of the stearic acid. SE composition (dry matter) Sucrose fatty acid ester = 94% (Ester distribution: monoester = 73%, diester or higher = 27%) Unreacted fatty acid methyl ester = 2% Soap = 2% Fatty acid = 1% Other = 1% When neutral salts are added to various concentrations, the added salt becomes salt,
When sodium sulfate, potassium lactate or potassium acetate is used, the results shown in Table 1 below are generally obtained. * Total salt = salt derived from catalyst + added neutral salt As is clear from the above table, the value of φ decreases as the amount of total salt increases. It can be seen that this value does not decrease even if it increases to more than%. Surprisingly, the above tendency is that even if the amount ratio of volatiles (residual reaction solvent) contained in the initial reaction mixture fluctuates greatly from 3.0 to 30.0%, and even if the neutral salt It was confirmed that even if the type changed, it was hardly affected. That is, in such an SE-water-salt ternary system, the value of φ is determined only by the concentration of the total salt, even if the amount of volatile components changes significantly and the type of neutral salt added changes. Although it is impossible to elucidate the mechanism of the surprising fact, at least it is certain that such a phenomenon is intricately intertwined with the degree of formation of SE micelle aggregates and the so-called salting-out effect of salt. Would. The degree of the above salting-out action, in other words, the value of φ varies somewhat depending on the ester distribution of SE and the type of fatty acid residue in SE, but the total salt amount exceeds 6% (water 94%). However, the tendency that the minimum value of φ does not decrease is the same. Conversely, when the amount is less than 6% (water 94%), the value of φ increases, and the dissolution loss of SE increases, which is not desirable. Therefore, in order to reduce the value of φ, it is desirable to keep the base at 6% (water 94%) or more, whereby the loss of dissolution of SE to the aqueous layer side can be minimized. (Washing) After the above salting-out operation, the pH was adjusted to 3.0 to 5.5 and the temperature was adjusted to about 10 to 40 ° C, and salting out and separation were performed using the adjusted acidic water.
Wash the SE cake. The acids used here include:
For example, mineral acids such as hydrochloric acid and sulfuric acid, and edible organic acids such as acetic acid and lactic acid are suitable, but not limited to those exemplified separately. By washing under such conditions, impurities can be transferred from the cake side to the aqueous phase side. Less than,
Table 2 below exemplifies the amount of SE dissolved in the aqueous layer when this washing with acidic water is applied to SE (sucrose stearate) starting from stearic acid methyl ester. In the table, φ is defined by the above equation (1). In the above washing process, if the temperature of the acidic water is 40 ° C. or higher, the operation is prolonged, and if the operation is extended for as long as several months, not only is the acid decomposition of SE concerned, but also the viscosity increases. Operation becomes difficult. On the other hand, maintaining a low temperature of 10 ° C. or less requires refrigerator equipment that is economically negligible. Therefore, usually 10-40 ℃,
In particular, operation near normal temperature is preferred. When washing the SE cake with this acidic water,
Since it is necessary to remove as much as possible the unreacted sugar, the added neutral salt and the salt by-produced by the neutralization of the catalyst contained in the cake from the SE cake, the SE cake is prepared in the acidic water. ,
It is desirable that the particles be subdivided to the smallest possible particle size. This object can be efficiently achieved by, for example, a subdivision device such as a dispersion mixer (eg, “Homomixer” manufactured by Tokushu Kiki Kogyo Co., Ltd.), a homogenizer, or a colloid mill (eg, “Mycolloider”). The reactive sugar, the salt derived from the catalyst and the neutral salt migrate from the cake of the precipitated SE into the acidic aqueous phase. However, at this time, while saying that the amount is substantially small,
It is inevitable that some SE will elute into the acidic aqueous phase. This tendency of dissolution in acidic water is stronger for SE containing more monoester, and can be reduced by relatively increasing the content of diester or triester. The above-mentioned washing of the SE cake with acidic water becomes more complete due to the increase in the number of washings and the amount of washing water, and thus, purified SE from which impurities such as neutral salts and unreacted sugars have been removed.
Can be obtained. (Neutralized mud) The water-containing SE thus purified is slurry (slurry)
In this state, the pH is unbalanced toward the acidic side. Therefore, the pH is adjusted to around neutral using alkali such as caustic soda. The resulting slurry does not contain unreacted sugars, salts of catalytic origin, sucrose and neutral salts added during salting out, but does contain SE, unreacted fatty acid methyl esters, soaps and fatty acids. , The solid content is often in the range of 1 to 50%, and the water content is in the range of 99 to 50%. The amount of solids in the slurry is preferably about 40% or less for drying, which will be described later. However, an excessively small amount of solids is not desirable from the viewpoint of drying energy cost, It is economically preferable to set the value to 4% or more. (Spray drying) In general, water-containing SE often forms an aqueous solution when the water content is 80% or more, and forms a slurry when the water content is less than 80%. Hydrous of such properties
SE has already been vacuum dried as usual

[Prior art]
As described in detail in the section, it is very difficult, and this is also considered to be one of the causes that the water-based purification has not been put into practical use. However, the present inventors have found from many experimental results that the spray drying method is the most suitable method for dehydrating and drying an SE slurry having a solid content of 4 to 40%. However, as described above, when a normal vacuum dryer typified by a so-called groove-type agitation dryer is used, the so-called slurry is continuously supplied, heated and discharged into a vacuum chamber. Even when a flash dryer is used, it is not possible to avoid quality deterioration phenomena such as an increase in the acid value, coloring, and caramelization of the SE to be treated due to the viscosity characteristics and low melting point of the SE. Furthermore, in the latter case, the danger of dust explosion cannot be ignored. However,
According to the adoption of the spray drying means found by the inventors,
The disadvantages of the SE drying means can be solved at once. In the drying step in the present invention, the water-containing SE in a slurry state
Is continuously supplied to a spray-drying tower via a pump, is divided into fine mist-like fine particles by spraying by a nozzle or centrifugal force of a rotating disk (disk), and is brought into contact with a dry air flow. As a result, the evaporation area of water is remarkably increased, so that dehydration and drying can be completed within a very short time (within a few seconds after spraying). As the atomization means, it is desirable to use a rotating disk because the viscosity of the water-containing SE is large. (Spray drying conditions) The supply temperature of the SE solution or slurry can be arbitrarily changed between 40 to 80 ° C, but preferably 40 to 60 from the viewpoint of quality.
Choose a temperature in the range of ° C. When the above solution or slurry is atomized by a rotating disk,
For example, when the diameter of the disk is 5 to 10 cmφ, 15,000 to 24,0
A rotation speed of 00 rpm is appropriate. The air blown into the tower should possess more heat than is necessary to evaporate the water in the solution or slurry, and therefore requires a larger amount of air when the air temperature is low. The air temperature at this time may be in a wide range of 10 to 100 ° C., but in consideration of the drying efficiency of the target SE and prevention of thermal decomposition,
It is advantageous to choose a temperature between 8080 ° C. The humidity in the blown air is related to the drying efficiency together with the air temperature. The absolute humidity suitable for work is roughly , But in particular, Is economical. If the solids concentration in the slurry sent to the spray drying tower exceeds 40%, the viscosity will increase significantly, and the particle size of the sprayed slurry will be relatively large, and the drying of water will be slowed accordingly. As a result, it easily adheres to the inner wall of the drying tower. Therefore, the solid content concentration in the slurry is preferably adjusted to 40% or less. If the solid content concentration of the slurry is 40% or less, the diameter of the sprayed droplets is smaller than that of a case where it exceeds 40%, and the droplets are easily dried, so that there is no fear of adhering to the inner wall of the drying tower. If the solid content of the slurry is small, for example, less than 3%, drying becomes easy, but it is uneconomical in terms of required energy. Therefore, the concentration of slurry supplied to the spray drying tower is preferably in the range of 4% to 40%. Various conditions such as the required area, required tower diameter, and required height of the spray drying tower are designed on the premise of the above spray conditions. With proper tower design and operating conditions, powdered dry SE with a water content of 5% or less is continuously discharged from the lower part of the spray drying tower. The resulting product has a very short heat history and is extremely excellent in quality, and requires little personnel for drying work.

[Action]

Unreacted sugar, unreacted fatty acid methyl ester, catalyst,
The pH of the SE-forming reaction mixture containing soap and fatty acids in the neutral region
When water and neutral salts are added and salted out at an appropriate temperature, SE, unreacted fatty acid methyl ester, soap and fatty acid precipitate. The precipitate is then washed with acidic water,
The result of elution of impurities such as unreacted saccharides, added neutral salts and salts by-produced by neutralization of the catalyst into the aqueous phase, while minimizing SE dissolution loss. Purified SE is obtained in the form of a slurry, and the slurry is spray-dried, whereby the object of industrially obtaining high-quality powdered SE without using a solvent for purification is achieved.

【Example】

Hereinafter, embodiments and effects of the invention will be described with reference to examples. However, the examples are, of course, for explanation, and do not delimit or enclose the idea of the invention. Example-1 A dried product obtained by neutralizing a residual solution obtained by distilling a reaction solvent from a solvent-based SE reaction mixture represented by a composition shown in Table 3 below with lactic acid and then drying.
2,000 g of water was added to 100 g to dissolve. To this aqueous solution, add 253.0 g of 50% potassium lactate and
Heat and raise the temperature until the precipitated cake is collected by filtration, and then
After drying at 80 ° C. and examining the composition of the solid, the following Table-4
It was as follows. The moisture in 123.1 g of the precipitated cake is
48.1%. The amount of SE in the filtrate obtained when the cake was separated by filtration was measured by gel filtration chromatography (GPC) method (see p. 63 of the above-mentioned publication), and the loss of SE was 1.5% of the initial amount. . Next, when 123.1 g of the above cake (consisting of 63.9 g of solid content and 59.2 g of water) of 2,000 g of aqueous hydrochloric acid (pH 3.5) at room temperature was added, SE immediately precipitated as a white precipitate. Next, the acidic aqueous solution (pH 3.5) containing this precipitate was sufficiently stirred and washed with a homomixer (manufactured by Tokushu Kiki Kogyo Co., Ltd.), and the precipitate was collected by filtration. An operation of adding the acetic acid water again to the precipitate separated by filtration and washing again was performed twice. After the washed precipitate was adjusted to pH 7.3 with caustic soda and dried at 80 ° C. under vacuum, a solid having the composition shown in Table 5 below was obtained. Upper SE precipitation cake (Hydrate in Table-5 above; Moisture = 47.2)
%) Was adjusted to a water content of 75.0% by adding water to 101.0 g, and then the slurry was supplied to a pilot spray-drying tower while being kept at 50 ° C., and spray-dried. Drying conditions are as follows: Spray drying tower diameter: 2.0mφ Length of straight tube: 1.5m Rotating disk (disk) diameter: 10cmφ Disk rotation speed: 24,000rpm Inlet air temperature: 65 ° C, Met. The powdery SE obtained from the lower part of the spray drying tower had a moisture content of 2.01
%, Bulk specific gravity 0.43, no coloring due to overheating, and good fluidity. No troubles such as powder adhering to the inner wall of the spray-drying tower were observed at the beginning of drying. The amount of monoester in SE was 49.3% before and after drying.
And there was no change in the acid value. Example 2 After distilling off the solvent from the reaction mixture of the solvent method SE represented by the composition in Table 3 above, 100 g of the mixture neutralized with lactic acid was added with 2,000 water.
0 g was added and dissolved. Next, 62.0 g of 50% potassium lactate was added to this aqueous solution, heated to 75 ° C. and heated, and a cake (water content: 50.5%) obtained in the same manner as in Example 1 below
The dried solid gave the composition in Table 6 below. When the amount of SE in the filtrate obtained when the cake was separated by filtration was measured by gel filtration chromatography (GPC) method (described above), the loss of SE was 1.2 g (2.6% of the initial amount). . Next, 56.2 g of a solid having the composition shown in Table 6 above and a water content of 5
Room temperature acetic acid aqueous solution (pH 4.0) 3,0 to 113.5 g of cake consisting of 7.3 g
Upon addition of 00 g, SE immediately precipitated as a white precipitate. Subsequently, the acidic aqueous solution (pH 4.0) containing the above precipitate was sufficiently stirred using a homomixer (described above), and the precipitate was collected by filtration. The precipitate was washed twice with an aqueous solution of acetic acid and then washed again, adjusted to pH 7.3 with caustic soda, and dried at 80 ° C. under vacuum to obtain a solid having the composition shown in Table 7 below. I got something. After adjusting the solid content to 20.0% by adding water to the above SE precipitation cake (above Table-7 hydrate), while maintaining the temperature at 50 ° C, the inlet air temperature was 55 ° C and the slurry feed rate was 0.5 kg / hour. Spray-drying was carried out in the same manner as in Example 1, except for the changes. The obtained SE powder had a water content of 1.20% and a bulk specific gravity of 0.41, had good fluidity, and had no coloring due to overheating. The monoester content in SE was 49.2%, unchanged before and after drying, and the acid value was the same. Further, no adhesion of the SE powder to the inner wall of the spray drying tower was observed.

【The invention's effect】

As described above, in the production of sucrose fatty acid ester, the present invention purifies the reaction mixture while minimizing the loss of sucrose fatty acid ester without using any organic solvent for purification, and purifies the purified sucrose fatty acid ester. Providing a technique for pulverizing without reducing the quality of sucrose fatty acid ester has the following direct and indirect effects industrially. (1) To be able to produce powdery high HLB sucrose fatty acid ester using only inexpensive water. (2) The ability to separate low HLB sucrose fatty acid esters. (3) Since the sucrose fatty acid ester can be dried in a short time under normal pressure, there is no thermal deterioration of the product. (4) There is no fear of explosion or fire of the solvent, so that expensive electric equipment of explosion-proof specification is not required. (5) There is no concern that the reaction solvent and the purification solvent are mixed into the product. (6) Improve the workplace hygiene environment. (7) It can be industrialized at low cost.

Claims (15)

(57) [Claims] 1. An unreacted sugar, an unreacted fatty acid methyl ester, a catalyst, a soap, in addition to a target sucrose fatty acid ester.
The reaction mixture containing volatiles and fatty acids is adjusted to pH in the neutral region, and the precipitate formed by adding water and neutral salt is washed with acidic water, and then neutralized, and then spray-dried. A method for producing a sucrose fatty acid ester. 2. The process according to claim 1, wherein the reaction mixture is adjusted to a pH of 6.2 to 8.2 with an acid. 3. The method according to claim 1, wherein the pH-adjusted reaction mixture is heated to 50 to 80 ° C. 4. The weight ratio of water and reaction mixture added to the reaction mixture is water: reaction mixture = 5: 1 to 40: 1.
The described method. 5. The acid used to adjust the pH of the reaction mixture,
The method according to claim 1 or 2, wherein the method is any one of acids selected from the group consisting of lactic acid, acetic acid, hydrochloric acid, and sulfuric acid. 6. The composition of the reaction mixture is as follows: sucrose fatty acid ester = 15.0 to 92.0% unreacted sucrose = 1.0 to 80.0% unreacted fatty acid methyl ester = 0.5 to 10.0% catalyst = 0.05 to 7.0% soap = 1.0 The method according to claim 1, wherein -10.0% fatty acid = 0.5-10.0%, volatile content = 3.0-30.0%. 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 common saturated fatty acid radical having 16 to 22 carbon atoms.
The described method. 8. The method according to claim 1, wherein the volatile component (remaining reaction solvent) in the reaction mixture is dimethylsulfoxide or dimethylformamide. 9. The neutral salt added to the reaction mixture is sodium chloride,
2. The method according to claim 1, wherein the salt is any one selected from the group consisting of sodium sulfate, potassium lactate and potassium acetate, and the weight ratio of water: neutral salt is ≤94 / 6. 10. The method according to claim 1, wherein the ester distribution of the sucrose fatty acid ester is 10 to 75% (90 to 25% for diester or more) as monoester content. 11. The method according to claim 1, wherein the pH value of the acidic water is 3.0 to 5.5. 12. The method according to claim 1, wherein the temperature of the acidic water is 10 to 40 ° C. 13. A slurry of a precipitate to be spray-dried (slurry).
The method according to claim 1, wherein the solid content is 4 to 40% and the water content is 96 to 60%. 14. The humidity and temperature of the blast air during spray drying are as follows: The method according to claim 1, wherein the temperature is in the range of 10.0 to 10.00.0C. 15. The method according to claim 1, wherein the composition of the powdery sucrose fatty acid ester of the product falls within the following range. Moisture = 0.5 to 5.0% Unreacted fatty acid methyl ester = 0.5 to 10.0% Soap = 0.5 to 60.0% Fatty acid = 0.5 to 10.0% Sucrose fatty acid ester = 98.0 to 15.0%