JPH02129194A - Method for purifying powdery sucrose ester of fatty acid - Google Patents

Abstract

PURPOSE:To obtain the subject in high purity without using an organic solvent by regulating a reaction mixture containing a sucrose ester of a fatty acid containing unreacted substances to a neutral pH, adding water, a neutral salt and sucrose thereto, adding water to dissolve the formed precipitates, subjecting the obtained solution to treatment with an ultrafiltration and reverse osmosis membranes and spray-drying the resultant slurry. CONSTITUTION:A reaction mixture, containing a sucrose ester of a fatty acid, unreacted sucrose, unreacted methyl ester of the fatty acid, catalyst, soap, fatty acid, etc., and synthesized by an aqueous medium method is regulated within a neutral region, preferably pH6.2-8.2, and preferably heated to 50-60 deg.C. Water, a neutral salt and sucrose are then added and water is further added to dissolve the formed precipitates. The resultant solution is then brought into contact with an ultrafiltration membrane to permeate and separate the unreacted sucrose and salt together with water through the above-mentioned membrane. An aqueous solution containing four of the residual sucrose ester of the fatty acid, unreacted methyl ester of the fatty acid, soap and fatty acid is subsequently brought into contact with a reverse osmosis membrane and slurried. The obtained slurry is then spray-dried to afford the objective ester.

Description

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

The present invention relates to a method for producing powdered sucrose fatty acid ester, and more particularly to a method for producing powdered sucrose fatty acid ester industrially using only water without using any solvent.

[Conventional technology]

(Background) Sucrose fatty acid esters, which are currently useful as surfactants, are produced industrially by combining Coffin and 68-C22 higher fatty acid methyl esters in a solvent (dimethylformamide, dimethyl sulfoxide, etc.) under an appropriate catalyst. (Solvent method: Japanese Patent Publication No. 35-13102); Alternatively, sugar is made into a molten mixture with fatty acid stone using water without using a solvent, and then reacted with higher fatty acid methyl ester in the presence of a catalyst (water It was obtained by a medium method (Japanese Patent Publication No. 14485/1983). However, in both of these two synthesis methods, the reaction mixture contains, in addition to the target sucrose fatty acid ester, unreacted sugar, unreacted fatty acid methyl ester, residual catalyst, soap, free fatty acid, etc. It contains impurities, and among these impurities, the impurities whose content exceeds the specified amount are
Among the impurities mentioned above, unreacted sugar must be removed before it becomes a product, and the removal of unreacted sugar is particularly important due to its large amount. (Problems with the prior art) By the way, as a means of removing unreacted sugar from a reaction mixture of sucrose fatty acid ester, one method is to remove unreacted sugar from a reaction mixture of sucrose fatty acid ester by taking advantage of the fact that ordinary solvents have almost no ability to dissolve sucrose. Conventionally, a method has been commonly used in which a solvent is added to the solution and contaminating unreacted sugars are removed as a precipitate. but,
Regardless of the small scale, in factories involved in the production of sucrose fatty acid esters on an industrial scale, the inconveniences of handling solvents, such as the trouble of recovering solvents, the risk of fire, and occupational health problems for workers, are of no concern. There is something left over. However, since there are no other effective means, solvents are still used to remove unreacted sugars, and this is explained in Japanese Patent Publications No. 11588-11588 and No. 10448-1973, which use butyl alcohol, toluene, methyl ethyl ketone, etc. , as specified that solvents such as ethyl acetate are effective for purification including removal of unreacted sugars. For reference, the disadvantages associated with handling solvents are listed below. ■ Risk of explosion or fire. ■ Explosion-proof electrical equipment in preparation for ■ above. ■ Seal the manufacturing equipment in preparation for the above ■. ■ The entire building will be made into a fire-resistant structure in preparation for ■ above. ■ Increase in fixed costs due to ■, ■, and ■ above. ■ Increased cost due to solvent wastage. ■ Negative effect of residual solvent remaining in the product sucrose fatty acid ester. ■A negative impact on the health of employees and an increase in costs due to increased man-hours.

[Question B that the invention attempts to solve]

Under these circumstances, there has been a long-awaited development of a technology that can synthesize and purify sucrose fatty acid esters without using any solvent, that is, without using any solvent other than water in both synthesis and purification. Ta. The problem to be solved by the present invention is to establish a technique for producing sucrose fatty acid ester without using any solvent.

[Means to solve the problem]

(Summary) To solve the above problems, the method for producing powdered sucrose fatty acid ester according to the present invention consists of unreacted sucrose synthesized by an aqueous medium method, unreacted fatty acid methyl ester,
Adjust the sucrose fatty acid ester-containing reaction mixture containing the catalyst, soap, fatty acid, etc. to a neutral pH range, and add water to dissolve the precipitate formed by adding water, neutral salt, and sucrose. The resulting aqueous solution is brought into contact with an ultrafiltration membrane under pressure to remove the remaining unreacted sucrose, the salt produced from the added sucrose and the catalyst, and the added neutral salt together with water. The aqueous solution containing the residual sucrose fatty acid ester, unreacted fatty acid methyl ester, soap, and fatty acid after separation through the membrane is brought into contact with a reverse osmosis membrane under pressure, or if necessary, the aqueous solution It is characterized by evaporating and concentrating the slurry to form a slurry with an appropriate degree of C, followed by spray drying. The principles of the invention, implementation conditions, and other details of the invention will be described below. (a *Nu-method SE synthesis reaction mixture) The method for producing SH by aqueous 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. A method (Japanese Patent Publication No. 51-14485, etc.), which has the advantage that the reaction mixture contains more 1-soap than the mixture obtained by solvent synthesis, but does not contain any residual reaction solvent. That's true. The SE reaction mixture synthesized by the aqueous 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 wine = IO
~50% fatty acids = 0.5-10%
At this time, the ester distribution of SE is monoester 10~
75% (diester or higher is 80-25z). The fatty acid roots mainly contained in each of fatty acid methyl ester, hexagonal fatty acid, and fatty acid are saturated and have a common carbon number of CI6 to C22. ((a-1 hydration) Next, water is added to the above reaction mixture, water: reaction mixture = 5: 1 to 40: 1 (weight ratio)... (1
), and more preferably, water:reaction mixture = 20:l (weight ratio)... (2) and the pH is adjusted to 6.2 to 8. .2, preferably pH 7.5. In this case, the water addition ratio is outside the above range. For example, 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, if too much water is added to the extent that the ratio of water to reaction mixture exceeds 40, the viscosity decreases and subsequent operations become easier, but on the other hand, unreacted sugar etc. When recovering water, a large amount of energy cost is required to remove water, resulting in a decrease in 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 8.2 or higher, quantitative alkali-based There is a risk of decomposition of SH, and even in a weakly acidic range of pH 6.2 or less, there is a risk of acid decomposition if exposed to high temperatures of, for example, 80° C. or higher. (a-2 Salting out) The aqueous solution of the SE reaction mixture, pH adjusted as above,
Maintain the temperature as much as possible at 50-80°C and add neutral salt and sucrose. In this case, the neutral salt to be added is first calculated by the following formula (
It is preferable that 3) is satisfied. = 0.015 to 0.12 (weight ratio)...
・(3) Here. Total base amount = amount of neutral salt to be added + amount of bases formed from the catalyst (4) Total amount of sugar = amount of sucrose to be added + unreacted from the beginning Sugar content...
(5) Next, the amount of sucrose to be added is preferably determined by the following formula (6). = 0.025~0.20 (I!!quantity ratio)...
...(6) Furthermore, in addition to both the above formulas, the ffi amount ratio of the total base amount and the total sugar amount is also. It is preferable that the following formula (7) is satisfied. The present inventors have discovered that SH obtained by adding an amount of neutral salt and sucrose that satisfies all three of the above formulas (3), (8), and (7)
It has been found that when an aqueous solution containing a precipitate is heated to a temperature of 50 to 80°C, almost all of the SE is precipitated. This phenomenon is a unique phenomenon, and for the purpose of the invention,
The attached Figure 1, which is of significant value, is a ternary graph that illustrates this phenomenon in more detail. In this figure, ffiM of SE dissolved in the aqueous phase = Y [g] Weight of precipitated SE = X [g] Total SE (X+Y) [g] Dissolved in the aqueous phase If the weight ratio of SH = φ [%], then φ is defined by the following formula (8). Here, the following conditions: Temperature = 80°C, pH -7.5° Water: Reaction mixture = 7.4: 1 (weight ratio) Fatty acid residue = Stearic acid Composition of the reaction mixture Sucrose fatty acid ester = 23% Reacted sugar = 35% Unreacted fatty acid methyl ester = 2% Salt derived from catalyst = 1% Soap 232% Fatty acid = 1% Ester distribution in SE: monoester = 65% diester or more = 35% What is the value of φ? This change is shown in triangular coordinates. Here, the total salt is the amount defined by the formula (4), and the total sugar is the amount defined by the formula (5), respectively, and they are expressed as water amount + total base amount + total sugar amount = 100%. The shaded part in Figure 1 is the formula (3) discovered by the present inventors.
), equation (6), and equation (7) at the same time. By determining the amount of dissolved neutral salt and sucrose that falls within this shaded area, it is possible to precipitate substantially φ=0, that is, approximately the entire amount of SE, and the precipitated SE can be collected by filtration. Alternatively, impurities dissolved in the aqueous phase can be completely separated by centrifugation. The SE precipitate obtained above still contains residual sugars and salts, so it is added with water in the next step to become water-soluble and treated with an ultrafiltration membrane to remove the residual sugars and salts. be done. (Blank below) (B Extremism) (B-1 Principle) The fact that sucrose fatty acid esters coalesce with each other under certain conditions in an aqueous solution to form an aggregate of high molecular weight micelle structures is as follows. Publicly known (Published by applicant company (Sugar S, Chill Story) 1
This is the fact (page 02). By the way, sugar fatty acid esters contain 1 to 3 08 atoms on each of the eight hydroxyl oxygen atoms of the sucrose molecule.
~There are types such as monoesters, diesters, and triesters in which C22 fatty acid residues are bonded.As is well known, monoesters have greater hydrophilicity than diesters and triesters, but have a lower degree of micelle formation in water. Because it is small, it has a relatively low molecular weight (small molecular diameter)
Forms sucrose fatty acid ester micelle aggregate. On the other hand, diesters and triesters have relatively low phyllophilicity but have extremely high micelle-forming ability, so they form sucrose fatty acid ester micelle aggregates with extremely large molecular weights (i.e., large molecular diameters) in water. do. Commercially available sucrose fatty acid esters are manufactured as single monoesters, and the monoester content is usually
For example, it is manufactured as a mixed composition of 70%, 50%, 30%, etc. As a result of repeated research aimed at solving the above problems, the present inventors found that 1. For example, sucrose fatty acid ester with a high monoester content of 70% is replaced by a sucrose fatty acid ester with a low monoester content of 50%. In comparison, since a sucrose fatty acid ester aggregate with a lower molecular weight is produced, the microscopic diameter of the aggregate is correspondingly smaller. % of sucrose fatty acid ester, and for this reason, it passes through the membrane together with unreacted sugars and by-product salts from the catalyst (formed when the catalyst is neutralized with acid). I learned that it has an undesirable tendency to be easy to use. Therefore, as a countermeasure to this problem, the present inventors have found that when it is desired to remove unreacted sugars, catalyst-derived salts, etc. from impure sucrose fatty acid esters with a high monoester content, it is necessary to remove unreacted sugars, catalyst-derived salts, etc.
On the other hand, in the case of sucrose fatty acid esters with a low monoester content, it is better to select a filtration membrane with a large molecular weight cutoff (i.e., a large pore size). It has been found that this method is convenient for speeding up the processing speed. In addition, the inventors found that among the substances contained in the reaction mixture, unreacted fatty acid methyl ester, soap, and the king of fatty acids exist in a state of being encapsulated in a micelle structure aggregate of sucrose fatty acid ester. Therefore, it has been confirmed from many experimental results that it is virtually impossible to separate sucrose fatty acid esters and their kings by filtration means. Thus, from many experiments, the conclusion was that the impurities that can pass through a filtration membrane (with an appropriate molecular weight cutoff) together with water using pressure as a driving source are unreacted minut, added sucrose, and the catalyst. On the other hand, substances that are incorporated into high molecular weight micelle aggregates and cannot pass through the filtration membrane are sucrose fatty acid esters, unreacted fatty acid methyl esters, soaps and Free fatty acids, etc. The present inventor cleverly utilized these ice cubes and selected a filtration membrane with an appropriate molecular weight cutoff to convert unreacted loquat and one of the catalyst-derived salts into sucrose fatty acid ester and unreacted loquat. It was successfully used to separate and remove fatty acid methyl esters, soaps, and fatty acids from their surroundings. (b-2i!! Molecular weight of target substance) Limit Il with appropriate molecular weight cutoff! In order to select an i-film, it is necessary to know the approximate molecular weight of the target substance.The molecular weights of these single substances related to the invention are as follows. ○ Sucrose = 342 0 Unreacted fatty acid methyl ester Stearic acid methyl ester; 290 0 When using hydrochloric acid generated by neutralization of the catalyst (K2 CO3) → Potassium lactate = 128 When using acetic acid → Potassium acetate = 98 0 Added neutral salt For salt = 58.5 0 Sucrose fatty acid ester (as a monomer that does not form micelle aggregates) Sucrose distearate = 600 Sucrose distearate = 858 Sucrose tristearate = 1,116 , myristate, palmitate, arachinate, behenate, and other fatty acid esters have similar molecular weights. ○6 Sodium stearate = 298 Potassium stearate = 314 0 Fatty acid stearic acid = 276 0 Wood = 18 By the way, the apparent molecular weight of the micellar structure aggregate of sucrose fatty acid ester (hereinafter referred to as sucrose fatty acid ester micelle aggregate The molecular weight of Since sucrose fatty acid ester in an actual aqueous solution forms a micelle aggregate in water, for example, when the number of micelle associations of sucrose fatty acid ester is 10, the molecular weight of the micelle aggregate is monoester Assuming 100%, ◇Molecular weight of monoester monomer (600) x 10=e
,oo. As 100% diester: ◇Molecular weight of diester monomer (850)! IO=8,
Assuming 580 triester 100%, ◇triester mi') molecular weight (1, IIG) XIO = 1
It becomes 1,160. Since the actual sucrose fatty acid ester is a mixture of monoester, diester, and triester, the average molecular weight may be defined as the molecular weight of the micelle aggregate of the sucrose fatty acid ester. <<b-3i! ! Molecular weight cutoff of membrane) Selection of a membrane suitable for the purpose of the invention is carried out as follows. First, in an ultrafiltration membrane with a molecular weight cutoff of 200, the reaction mixture in the aqueous solution state is fed to the ice membrane under pressure, and unreacted sugar from SE, added sucrose, and the salt generated from the catalyst (K2CO3) are removed. Even if you aim to remove the added neutral salts, the filter membrane can separate only 1+! Water, catalyst (K
2Cox) and added neutral salts. Sucrose with a molecular weight of 342, which is larger than the molecular weight cutoff of 200, does not pass through the sieve membrane at all, so the unreacted side cannot be separated and removed from the sucrose fatty acid ester. Next, in the case of IIL2 with a molecular weight cut-off of 5,000, since the molecular weight of each of the particles is smaller than 5,000, they can easily pass through the pores of the filter membrane. The sucrose fatty acid ester constitutes the above-mentioned micelle aggregate, and assuming that the number of micelle associations is, for example, 10, the molecular weight of the sucrose fatty acid ester micelle aggregate is estimated to be s,ooo or more. Therefore, it is presumed that if the molecular weight cutoff of the filtration membrane is greater than 5.000, the micelle aggregates cannot pass through the micropores, but this presumption has been experimentally confirmed. Finally, we also investigated the case of a filtration membrane with a molecular weight cutoff of 1,000, and the results were as expected. In this way, by appropriately selecting the angle of 41° between the two molecules of the ultrafiltration membrane, it becomes possible to remove impurities including unreacted side from the sucrose fatty acid ester reaction mixture. <<b-4i! ! Conditions to be met for the membrane) The unreacted sugar contained in the sucrose fatty acid ester reaction mixture, the added sucrose, the salt by-produced from the catalyst (K2O [13), and the added neutral salt are removed] When attempting to separate sugar fatty acid esters, soaps, unreacted fatty acid methyl esters, and fatty acids from the surroundings, the filtration membrane must have an appropriate molecular weight cutoff. ■ Must be resistant to physical external forces. ■ Must be heat resistant and not decomposed by microorganisms. ■ Appropriate molecular weight cutoff and high processing power. ■ Long service life. (!8) Must be available at an economical price. etc. In recent years, the limit of over-harvesting! Since there have been remarkable advances in technology in A construction, even reprints can be found that meet the above conditions as described below. (Actual practice of b-5 ultrafiltration) The composition of the reaction mixture suitable for carrying out the present invention is as follows: Fatty m ester 15% to 95% unreacted sugar 1.0% to 80% unreacted fatty acid Methyl ester 0.5%~10%, catalyst (K2
CO) 0.05% to 7%, soap
2.0%-60%, fatty acid 0.5
%~10%. This is within the range. When attempting to remove the unreacted side, the salt generated from the neutralization of the catalyst (K2CO3) and the acid, and the sucrose and neutral salt surroundings added in the previous step from a reaction mixture with this composition by ultradirect flow. 1 The fatty acid methyl ester in the reaction mixture has 016 carbon atoms in the fatty acid residue.
The sucrose fatty acid ester of ~C22 and derived therefrom is preferably saturated. As a catalyst for sucrose fatty acid ester synthesis,
Potassium carbonate (K2CCh) is a typical example, but catalysts used in general alcoholysis reactions, such as sodium carbonate and sodium alkoxide, can also be used. The types of soap and fatty acid may correspond to the above-mentioned fatty acid methyl ester. In carrying out the present invention, the sucrose fatty acid ester reaction mixture to be synthesized by the water-null method described above is adjusted to p)l in the neutral region, and the wood containing the neutral salt and sucrose is subjected to the water:reaction as described above. More preferably, water:reaction mixture = 20:1 (weight ratio) so that the mixture = 5:l to 40:l (weight ratio)
and dissolved in the reaction mixture. Sucrose fatty acid esters are easily hydrolyzed in alkaline conditions, so to prevent hydrolysis, the pH of the solution should be adjusted to 6.5 to 8.
．． Adjust to 0. At this time, as the acid used to adjust the pH to 2g1, an organic acid such as lactic acid or acetic acid, or an inorganic acid such as hydrochloric acid or sulfuric acid is used. In this way, approximately the entire amount of sucrose fatty acid ester is precipitated. Since impurities are still attached to this precipitate, note the precipitate cake.
The inventors have found that impurities can be removed by adding water to the precipitate cake and heating it as necessary to obtain SE in a dissolved state. It has been found that maximum filtration rates are obtained especially when within the temperature range of 40-60°C. That is, e overtemperature is 4
By adjusting the temperature to 0 to 60°C, optimally around 50°C, sugar and salt pass through the filtration membrane most efficiently together with water for the reasons described below. The reason for this is that at 40 to 60'C, the molecules of the micelle aggregates of sea it B fatty acid ester become large, resulting in a decrease in the total number of micelle aggregates, and the formation of micelle aggregates on the unreacted side, etc. This is presumed to be due to the fact that non-participating substances are less susceptible to the resistance of the sucrose fatty acid ester, making it easier for unreacted substances to pass through. As is known, sucrose fatty acid ester aqueous solution generally has a concentration of 40
~． It shows the maximum viscosity between 60°C (cited above, p. +03), which suggests that it can have the maximum molecular weight within that temperature range, and from this JG fact, 40°C
This can explain the reason why unreacted sugars etc. show the maximum passing rate in the range of ~60°C. Thus, the reaction mixture containing the sucrose fatty acid ester, which was maintained at 40 to 60°C, was pumped for 1 to 2 minutes.
Pressure is applied as a driving source to 0 Kg/cm2G, and the ultrafiltration membrane is brought into contact with the hydrogen ion concentration range of PH6.2 to 8.2. Cellulose-based membranes are not only physically weak but also easily attacked by microorganisms, so they are not very desirable for practical purposes.Polysulfone reinforced with a support layer is preferable for practical purposes. or polyvinylidene fluoride. Both types of filtration membranes are currently being reprinted and have excellent heat resistance, acid resistance, and alkali resistance, are resistant to external physical forces, and, moreover, microorganisms do not grow on the membrane surface. As mentioned above, when determining the molecular weight cutoff of a filtration membrane, it is important to select a membrane that can efficiently separate unreacted sugars, etc. without leaking sucrose fatty acid ester, and has a high filtration rate. As a result of consideration, the important 0 shots and 11 etc.
The molecular weight cut-off of a membrane that satisfies the desired conditions of high leakage of sucrose fatty acid ester, unimpaired separation of sugar and salt, and high filtration rate is from 1,000 to 1,000.
The fractional molecule i5 is preferably within the range of 100.000, and is particularly suitable for processing on an industrial scale without leaking sucrose fatty acid ester.
,000 filtration membranes were found to be most preferred. 5
If the molecular weight cut-off exceeds 5,000, leakage of sucrose fatty acid ester occurs, albeit slightly;
For membranes with molecular weight cutoffs below, the filtration rate decreases. However, in either case, it does not bring about such a disadvantage that it is not industrially profitable. Among the currently reprinted filtration membranes, four that meet the purpose of the invention are, for example, among the ultrafiltration membranes sold by Toshi Engineering ■, the product name (TERP-E-5) (polyvinylidene fluoride), <(TERP-HF-10>> (Polysulfone type) and (TERP-HF-100>>
(polysulfone type), etc. The above filtration membrane (↑ERP-HF-10) (molecular weight cutoff = 1
0.000), an aqueous solution (pH -7.5) of a seal sugar fatty acid ester reaction mixture, the composition of the aqueous solution is as shown in Table 1 below, the temperature is 50°C, the driving pressure is 5
．． The separation rate of unreacted sugar when increasing to 0 Kg/cm'G is the same as that of an ultrafiltration membrane with an effective area of 8 m' (1 unit dust).
and reached 5.0 Kg-sugar/hour. This is an industrially sufficient separation rate. Moreover, the salt separation rate was also sufficient. Incidentally, since the removal rate of sugars and salts can be sufficiently increased by adjusting the number of times the liquid passes through the filtration membrane, the ice film is extremely advantageous for industrialization. Unreacted sucrose catalyst (K2 CO3) Unreacted fatty acid methyl (stearic soap (potassium stearate) Fatty acid (stearic acid) Subtotal water aqueous solution 47.0 0.5 )) 1.5 3.0 +, 0 100.0 Kg 2.000. OKg 2.100.0 Kg In this way, by using an ultrafiltration membrane, unreacted sugar and by-product salt from the catalyst (K2c:03) can be easily removed industrially from the sucrose fatty acid ester reaction mixture. It becomes possible to remove the water all at once, and thus the water,
Sucrose and neutral salts achieve the objective of removing unreacted sugars and by-product salts from the catalyst (K2CO3) without using any solvent. (C reverse osmosis) The residual liquid (sucrose fatty acid ester, unreacted fatty acid an aqueous solution containing a mixture of methyl esters, soaps and fatty acids)
The composition is approximately 1% to 4% solid and 88% to 96% water.
Therefore, it is clear that the energy cost for dehydration to obtain sucrose fatty acid ester will be excessive if used as is. However, as a result of research, the present inventors have found that the use of a reverse osmosis membrane allows dehydration and concentration to be carried out at extremely low cost, making it possible to solve the above problems industrially. The conditions for the reverse osmosis membrane used here are: ■ It must be able to permeate only water from the aqueous solution after ultraviolet passage, ■ It must not deteriorate due to the growth of bacteria, and ■ It must be heat resistant and alkali resistant. , ■ Excellent water removal ability ■ Long service life, etc. As a result of our research, the present inventors have found that in particular, polyether membranes are reinforced with polysulfone supports.
It has been found that a reverse osmosis membrane made of a so-called composite membrane and having a molecular weight cutoff of 60 is suitable. A commercially available product suitable for this purpose is, for example, PEC100O sold by Toshi Engineering Co., Ltd. The above reverse osmosis membrane is pre-heated at a temperature of 40°C to Cθ°C, a pH of 8,
When the aqueous solution to be treated, which is adjusted within the range of 2 to 8.2, is brought into contact under pressure, effective dehydration can be carried out. At this time, if the pH is less than 6.1, sucrose fatty acid ester precipitates and blocks the pores of the reverse osmosis membrane, making it impossible for only water to pass through the pores. Conversely, if p)l exceeds 8.3, fatal hydrolysis of sucrose fatty acid esters will occur, so do not make the alkalinity any higher than this.Furthermore, if the temperature drops below 40℃, water The rate at which molecules pass through the pores of the reverse osmosis membrane decreases rapidly. On the other hand, if the temperature exceeds 60°C, there is a concern that the sucrose fatty acid ester will be hydrolyzed, especially when subjected to long-term reverse osmosis, and this should also be avoided. Note that these optimum operating conditions of 40 to 60°C were also found by the present inventors, similar to the ultrafiltration temperature described above. The pressure as a driving source is industrially preferably 50 kg.
/c layer 2G to 85kg/c2G. Under these conditions, the approximate water removal rate is 0 per rrr' of reverse osmosis membrane.
．． 06 to 0.8, water is 7 minutes, which is a large value on an industrial scale. Under the above preferred conditions, the aqueous solution containing the Nishisha mixture is dehydrated to have a water content of 60-96% and a solid content of 4.
It is concentrated to 0-4%. If necessary, a concentration method other than a reverse osmosis membrane, such as an evaporation e-ray method under vacuum, may be used in combination to achieve a concentration higher than the above value. can do. However, it is not preferable to concentrate it to a concentration that makes it difficult to apply the spray dry explosion method described below. (d Spray drying) The e-condensed liquid (residual liquid) obtained by reverse osmosis etc. has a moisture content of 60 to 96%.
It is a type of slurry containing %. A conventionally known vacuum dryer (
For example, a groove-type agitating dryer) can be used, but as a result of research, the inventors found that spray drying is particularly suitable for dehydrating and drying the sucrose fatty acid ester slurry. Incidentally, dehydration and drying using a normal stirring type vacuum dryer is difficult due to the high viscosity of the sucrose fatty acid Nissel aqueous solution, and as a result, the work is forced at high temperatures and for a long time, resulting in decomposition of the sucrose fatty acid ester. Increase in acid value due to
It is known that undesirable phenomena such as strong coloration and caramelization are caused (see Japanese Patent Publication No. 37-9968).Furthermore, the so-called method of continuously heating the slurry, supplying it to a vacuum chamber, and discharging it, Even in the case of a flash dryer, the large latent heat of water (500Kcal/K
However, even if these difficulties could be overcome, the sucrose fatty acid ester would melt after being dehydrated and dried under vacuum. Because of this, it is necessary to take it out of the dryer, cool it by blowing cold air to below its melting point, solidify it, and then crush it. The above is a summary of the dehydration and drying methods for obtaining powdered sucrose fatty acid ester: ■ Dehydration and drying of slurry under vacuum. ■ Taking out the molten sucrose fatty acid ester from a vacuum dryer, ■ Cooling and solidifying the taken out melt, ■ Grinding the solidified sucrose fatty acid ester. Since it requires multiple steps, it is economically undesirable, and in particular, the crushing step (2) is accompanied by concerns about dust explosions. However, according to the means for dehydrating and drying a silica fatty acid ester slurry by spray drying according to the present invention, the drawbacks of the above-mentioned drying means can be completely overcome. That is, the slurry is continuously fed to the spray drying tower via a pump, and the slurry fed via a nozzle or rotating disk, preferably the latter, is dispersed and atomized, thereby making the evaporation area of water extremely large. Therefore, dehydration and drying can be completed within a few seconds after spraying. The temperature of the slurry supplied to the spray drying tower is 40
A temperature in the range of ℃ to 80℃ is selected, but from the viewpoint of quality, it is preferably within the range of 40℃ to 60℃.
When dispersing with a rotating disk, the diameter of the disk is 5 to 1
When 0cmφ, 15. OOOrpm ~24.00O
The rotation speed in rpm is appropriate. The heated (warm) air that is blown should have more than the amount of heat required to evaporate the water in the slurry, so naturally a large amount of air is required when the air temperature is low. The air temperature can be selected between 10°C and 100°C, but in order to avoid deterioration of the product sucrose fatty acid ester, the air temperature should be set between 60°C and 100°C.
Should I choose between 80°C? Delicious. The humidity in the blown air is also determined along with the air temperature, but it is generally economical to select the value of absolute humidity. Factors such as the volume, tower diameter, and height of the spray drying tower should be designed based on the above spray conditions, if the zero condition is appropriate.
Powdered sucrose fatty acid ester with a moisture content of 5% or less is delivered to i! from the bottom of the spray drying tower. lI! It is taken out continuously.

[Effect]

Among the various reaction mixtures contained in the sucrose fatty acid ester reaction mixture, a large proportion of impurities are removed by the synergistic salting-out effect of salt and neutral salt on SE.
Sucrose fatty acid ester forms micelles with water, and
Unreacted fatty acid methyl esters, stones, and fatty acids are encapsulated in these micelles, and none of these can pass through the ultrafiltration membrane, whereas the micelle and salt are ultrafiltered together with water. Since it can pass through a membrane, the latter two can be separated from the former four.Next, the remaining liquid (including SE and others) that was not passed through the ultrafilter is dehydrated by reverse osmosis and made into a slurry. By spraying and drying, a purified powdered sucrose fatty acid ester can be economically produced from a sucrose fatty acid reaction mixture having a composition without using any solvent other than water.

【Example】

Hereinafter, the embodiments and effects of the invention will be explained with reference to Examples, but the examples are of course for illustrative purposes and are not intended to limit the connotation or extension of the idea of the invention. Example-1 Potassium carbonate (K2C03) and sodium stearate were added to an aqueous mixture of stearic acid methyl ester and sucrose, heated according to a conventional method (aqueous medium method synthesis), and transesterified under vacuum. A reaction mixture having the following composition was obtained. (Left below) Sucrose fatty acid ester (monoester amount = 58%) 31.5% unreacted sucrose 34.1% unreacted methyl stearate 2.8% stearic acid
2CIh to 1.8%
0.9% stearate
28.9% subtotal 10
4,100 kg for 100 kg of reaction mixture with 0.0% or more
of water (containing 78 kg of sucrose and 82 kg of salt) was added, and the mixture was stirred at 50° C. for 60 minutes. A white SH precipitate cake was formed, and the pH of the solution was adjusted to 7.8 in advance. The precipitate cake was separated and dissolved by adding water at 50°C. This aqueous solution was transferred to a spiral-shaped 4" cylindrical unit with a membrane area of 8rn' equipped with an ultrafiltration membrane (trade name (TERP-E-5>> (molecular weight cut off 5,000) sold by Toshi Engineering Kai). The operating conditions at this time were: Feeding pressure = IO, okg/cs2G Liquid feeding temperature = 5 Liquid feeding temperature -53.5°C Solid content concentration in the liquid = 6.0%. Start of liquid feeding. Nine hours later, 33% of the sucrose discharged from the filtration membrane had been removed.Also, the leakage of sucrose fatty acid ester into the e solution was only a small amount compared to the amount originally contained in the reaction mixture. 0.1%. 37.0% of the salt was removed. Through the above operations, the volume of the reaction mixture subjected to efli5 was 2,800 kg, and on the other hand, the volume of the ejected fluid that passed through the cancer tube was 2,800 kg. was 1,400 kg.Next km2.::(7)etlaj&2,800kg D,1TrU2,800kg cr) Add deionized water and stir at 50°C for 60 minutes to dissolve and adjust the pH to 7.4. After that, it was again fed to the above-mentioned filtration membrane. When the operation was carried out under almost the same conditions as above, 2,800 kg of concentrated liquid was obtained after 18 hours of passing the liquid. The target sucrose stearic acid It was found that more than 99% of the ester was recovered, and that 75% of the sugar and approximately 79% of the salt were removed.However, unreacted methyl stearate, stearic acid, and stearate were removed. The king was not removed because it was accompanied by sucrose stearate.Next, 2,800 kg of the above reconcentrated solution was poured into a reverse osmosis membrane (product name (PE1000) sold by Tohoku Engineering Co., Ltd.).
)) Molecular weight cut off = 60) was supplied at a temperature of 50° C. to a spiral-shaped cylindrical unit with a membrane area of 8 ml and equipped with a neck. The operating conditions at this time are sending pressure = 57kg/cI112G ~ 59kg/cm
p)I of 2G liquid = 7°8. This concentrated solution was immediately supplied to a spray drying tower while maintaining the temperature at 50°C, and was spray-dried. The drying conditions were as follows: Spray drying tower diameter: 2.0 m, straight cylinder: 1.5 cm, rotating disk diameter: 10 c++, rotation speed: 20. OOOrpm Inlet air temperature was 80°C. After 16 hours, the amount of concentrated liquid that was C&condensed with the reverse osmosis membrane was 1.
400 kg (calculated amount of liquid discharged was 1,400 kg)
). Thus, it has been found that only approximately half of the water in the concentrate can be removed through the reverse osmosis membrane. In addition, the amount of substances observed in the &1 liquid was observed, and the feed rate of the concentrated liquid was 0.
．． It was 8 kg/hour. The powdered sucrose fatty acid ester obtained from the lower part of the spray drying tower has an adhesion value of 3.5, no coloring due to heating, and a moisture content of 1.
It had good fluidity with a filtration fi of 90% and 0.44.Drying was stable for about 2 hours and 1! There were no problems such as adhesion to the inner wall of the spray drying tower, which was initially feared. The amount of monoester in the obtained sucrose fatty acid ester was 57%, which was completely unchanged from before drying.

【Effect of the invention】

As explained above, 1. The method for producing powdered sucrose fatty acid ester according to the present invention skillfully combines SE precipitation with water containing sucrose and a neutral salt, an ultradirect method, a reverse osmosis method, and a spray drying method. By doing so, without using any organic solvents,
The present invention can provide a technology for economically mass producing highly pure citrus and loquat fatty acid esters, and has great industrial value. The advantages of the invention are listed below for reference: (1) Powdered sucrose fatty acid esters can be produced using inexpensive water without using any solvents in either synthesis or purification. ■ The sucrose fatty acid ester can be dried under normal pressure within a short time, so there is no thermal deterioration of the product due to drying. Q) Since no organic solvent is used, there is no need for expensive explosion-proof electrical equipment. ■ Since no organic solvent is used, there is no risk of explosion or fire caused by the solvent. ■ Since no organic solvent is used, there is no risk of solvent entering the product. ■ Since no organic solvents are used, there is no negative impact on employees due to solvent vapors. ■ It is extremely easy to create an industrial-scale plant for the reasons listed above. ■ It is possible to create a safe and low-cost plant.

[Brief explanation of the drawing]

FIG. 1 is a ternary graph showing the relationship between changes in the amounts of water, total sugar, and total salt and SEi dissolved in the aqueous phase. Patent applicant Daiichi Kogyo Seiyaku Co., Ltd.

Claims (1)

[Claims] 1. Unreacted sucrose, unreacted fatty acid methyl ester,
A sucrose fatty acid ester-containing reaction mixture containing a catalyst, a soap, a fatty acid, etc., which is to be synthesized using an aqueous medium, is adjusted to a pH in the neutral range, and water, a neutral salt, and sucrose are added to form a precipitate, and then water is added. It is dissolved and brought into contact with an ultrafiltration membrane, and unreacted sucrose and salt are passed through the membrane together with water to separate the remaining sucrose fatty acid ester, unreacted fatty acid methyl ester, soap, and fatty acid. A method for producing a powdered sucrose fatty acid ester, which comprises contacting an aqueous solution containing the same with a reverse osmosis membrane to form a slurry, and then spray-drying the slurry. 2 The composition of the reaction mixture is: Unreacted sucrose = 1.0-80% Unreacted fatty acid methyl ester = 0.5-10% Catalyst (as K_2CO_3) = 0.05-7% Soap = 2.0-60% The manufacturing method according to claim 1, wherein fatty acid = 0.5 to 10% and sucrose fatty acid ester = 15 to 95%. 3. The manufacturing method according to claim 1, wherein the reaction mixture is adjusted to pH 6.2 to 8.2. 4. The manufacturing method according to claim 1, wherein the reaction mixture after pH adjustment is heated to 50 to 80°C. 5. The production 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 method of claim 1, wherein the neutral salt and sucrose are added to the reaction mixture according to the following relationship: Total salt amount / (water amount + total salt amount + total sugar amount) = 0.015
~0.12 and total sugar amount/(water amount + total salt amount + total sugar amount) = 0.025
~0.20 and total amount of salt/total amount of sugar = 0.4 to 0.6 where, total amount of salt = amount of neutral salt to be added + amount of salt generated by neutralization of catalyst Total amount of sugar = added amount of sucrose to be added + amount of unreacted sugar from the beginning 7 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. 8 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.
The manufacturing method according to claim 1 or 2, having 6 to 22 common saturated fatty acid roots. 9. The production method according to claim 1 or 6, 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. 10 The ester distribution of sucrose fatty acid ester is 10 to 75% as monoester content (diester or more is 5%).
3. The manufacturing method according to claim 1 or 2, wherein the amount is 0% to 25%). 11 The ultrafiltration membrane is composed of polysulfone-based or polyvinylidene fluoride-based resin, and has a molecular weight cut-off of 1,
The manufacturing method according to claim 1, wherein the molecular weight is from 000 to 100,000. 12. The manufacturing method according to claim 1 or 5, wherein the pressure during ultrafiltration is 1 to 20 kg/cm^2. 13. The manufacturing method according to claim 1, wherein the reverse osmosis membrane is made of a polyether resin and has a molecular weight cut off of 60. 14 Pressure during reverse osmosis is 50-85kg/cm^2G
The manufacturing method according to claim 1 or 13. 15. The manufacturing method according to claim 1, wherein the aqueous solution is brought into contact with a reverse osmosis membrane and the aqueous solution is further evaporated and concentrated to form a slurry. 16 The solid content in the slurry containing sucrose fatty acid ester, unreacted fatty acid methyl ester, soap and fatty acid is
The manufacturing method according to claim 1, wherein the content is 4 to 40%. 17 The humidity and temperature of the blown air during spray drying are as follows: absolute humidity = 0.008 to 0.05 [(kg・water)/(k
The manufacturing method according to claim 1, wherein the temperature is 10.0 to 100.0°C. 18. The manufacturing method according to claim 1, wherein the composition of the powdered sucrose fatty acid ester product is within the following range. Moisture = 0.5-5.0% Unreacted fatty acid methyl ester = 0.5-10.0% Soap = 0.5-80.0% Fatty acid = 0.5-10.0% Sucrose fatty acid ester = 98 .0~15.0%