JPH0296586A - Method for purifying sucrose ester of fatty acid - Google Patents

Abstract

PURPOSE:To purify sucrose ester of a fatty acid without using a solvent other than water by adding water containing a neutral salt to a reaction mixed of sucrose-fatty acid ester synthesis by an aqueous medium method containing an unreacted material, dissolving the resultant precipitate cake in water, then bringing the formed solution into contact with an ultrafiltration membrane and further with a reverse osmosis membrane. CONSTITUTION:Water containing a neutral salt (example; common salt) is added to a reaction solution of sucrose fatty acid ester synthesis by an aqueous medium method containing an unreacted sucrose, unreacted fatty acid methyl ester, catalyst, soap, fatty acid, etc., other than sucrose ester of a fatty acid, the resultant precipitate cake is dissolved in water. The formed solution is brought into contact with an ultrafiltration membrane (preferably composed of polysulfone-based resin or polyvinylidene fluoride-based resin and having a fractionating molecular weight of 1000-100000) to permeate and separate the unreacted sucrose and salt with the water therefrom. An aqueous solution containing remaining components is brought into contact with a reverse osmosis membrane (preferably composed of polyether-based rein and having a fractionating molecular weight of 60) and concentrated.

Description

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

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

[Conventional technology]

(Background) Currently, sucrose fatty acid esters useful as surfactants are produced industrially by reacting sucrose and 08-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), or sucrose is made into a molten mixture with fatty acids using water without using a solvent, and then reacted with higher fatty acid methyl ester in the presence of a catalyst (water-based method). method: 4, Shiko No. 51-14495). However, in both of these two synthesis methods, in addition to the target sucrose fatty acid ester, the reaction mixture contains unreacted sugar, unreacted fatty acid methyl ester, residual catalyst 1 soap, free fatty acid, Contains impurities such as volatile matter, and among these impurities, impurities whose content exceeds the specified amount must be removed before becoming a product.In particular, among the above impurities, unreacted sugars must be removed. The removal of
It is the most important because of its large amount. (Problems with the prior art) By the way, as a means of removing unreacted sugar from the reaction mixture of sucrose fatty acid ester, one method is to remove unreacted sugar from the reaction mixture 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,
Apart from small-scale factories, factories involved in the production of sucrose fatty acid esters on an industrial scale face the inconvenience of handling solvents, such as the trouble of recovering solvents, the risk of fire, and occupational health problems for workers. There is something noticeable. However, since there are no other effective means, solvents are still used to remove unreacted sugars. As specified, 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. (li) Make electrical equipment explosion-proof in preparation for the above ■. ■ Seal the manufacturing equipment in preparation for the above ■. (4) Make the entire building fireproof in preparation for the above (0). ■ Above ■, ■ , ■Increase in fixed costs due to ■Increase in cost due to wear and tear of the solvent.■Negative effect of residual solvent remaining in the product sucrose fatty acid ester. (Φ) Adverse impact on employee health and, in turn, increase in man-hours. increase in cost.

[Problems to be Solved by the Invention] Under these circumstances, sucrose fatty acid esters have been synthesized without solvents, that is, without using any solvent other than water in both the synthesis and purification steps. The problem that the present invention aims to solve is to establish a technology for refining sucrose fatty acid ester without using any solvent. [Means for Solving the Problems] (JIE Required) In order to solve the above problems, the method for purifying sucrose fatty acid esters according to the present invention includes
Water containing neutral salt is added to the water-borne sucrose fatty acid ester synthesis reaction mixture containing unreacted sucrose, unreacted fatty acid methyl ester, catalyst 1 soap, fatty acids, etc., and the resulting precipitate cake is dissolved in water. After that, it is brought into contact with an ultrafiltration membrane to separate unreacted sucrose and salt together with the wood by passing through the Iλ,
The method is characterized in that an aqueous solution containing the remaining sucrose fatty acid ester, unreacted fatty acid methyl ester, soap, and fatty acid is concentrated by contacting with a reverse osmosis membrane. That is, in the purification method of the present invention, a sucrose fatty acid ester-containing reaction mixture containing unreacted sucrose, unreacted fatty acid methyl ester, catalyst, right end, fatty acid, etc. synthesized by a water medium method is heated to a neutral pH. After adjusting the temperature to be within the range, water containing neutral salts is added at an appropriate temperature, the precipitated cake is separated by filtration and dissolved in water, and the resulting aqueous solution is brought into contact with ultrafiltration units 11 under pressure. The unreacted sucrose, the salt generated from the catalyst, and the added neutral salt are separated by passing through the membrane together with water, and the remaining (unpermeated) sucrose fatty acid ester, unreacted fatty acid methyl ester, The gist is to contact an aqueous solution containing four of soap and fatty acids with a reverse osmosis membrane under pressure to e-condense it, or if necessary, further evaporate water from the eA condensed ice aqueous solution to form a slurry. It is something. The principle of invention 1, implementation conditions, and other details of the invention will be described below. (a. Precipitation of sucrose fatty acid ester with water in which neutral salts are dissolved; salting out) Aqueous solution of sucrose fatty acid ester reaction mixture adjusted to pH 6.5 to 8.0 and temperature of 10 to 40°C. To,
When water in which a neutral salt is dissolved is added, sucrose fatty acid ester (hereinafter also referred to as "SE") precipitates into a cake-like form, and impurities such as unreacted sucrose become a solution, which is then removed in the next step. Impurities can be removed from the cake side. Neutral salts used here include, for example, common salt, mirabilite, acetate, and lactic acid 1'i! etc., but it is not limited to those specifically exemplified. During the above SH precipitation operation, the temperature of the reaction mixture was 40°C.
If the temperature exceeds .degree. C., there is a concern that the SE will not only decompose if the operation lasts for a long time, for example, several months, but also the viscosity will increase, making the operation difficult. On the other hand, in order to maintain a low temperature below to'c, a refrigerator is required, taking economical considerations into consideration. Therefore, it is usually preferable to operate at a temperature of 10 to 40°C, especially around room temperature. In addition, in the salting out treatment of SE with water containing this neutral salt, it is possible to remove the unreacted sugar remaining in the SE cake, the added neutral salt, and the salt by-produced by neutralization of the catalyst. Since it is necessary to remove as much as possible from the SE cake, it is desirable that the SE cake be subdivided in the water to the smallest possible particle size. (manufactured by Homomixer)), a homogenizer, or a colloid mill (for example, the product name (Mycolloider)).
The unreacted side, the salts from the catalyst and the added neutral salts, migrate from the precipitated SE cake into the aqueous phase. However, although it is a substantially small amount, it is inevitable that some SE will elute into the aqueous phase at this time. This tendency to dissolve in water is stronger as SE has a higher monoester content.
It can be reduced by relatively increasing the diester or triester content. After the SE is precipitated by the above operations, it is filtered and water is added to the SE precipitate to prepare an aqueous solution of SH, which is then subjected to the next ultracritical process. (b Ultrafiltration) (b-1 Overview) It is well known (applicant company For (Sugar Esther Story) 10
This is the actual vehicle (page 2). By the way, sucrose fatty acid ester contains three molecules of sucrose.
1 to 1 to each of the oxygen atoms of the primary hydroxyl groups
There are several types of monoesters, diesters, and triesters in which three 08-C22 fatty acid residues are bonded.As is well known, monoesters have greater wood-philicity than diesters and triesters, but they are less susceptible to water in water. Since the degree of micelle formation is small, they form sucrose fatty acid ester micelle aggregates with a relatively low molecular weight (small molecular diameter).On the contrary, diesters and triesters have a relatively low affinity for sucrose and triesters. Since it has an extremely high micelle-forming ability, it forms sucrose fatty acid ester micelle aggregates with an extremely large molecular weight (that is, a large molecular diameter) in water. Commercially available sucrose fatty acid esters cannot be manufactured as a single monoester, and the content of the monoester is usually
For example, it is manufactured as a mixed composition of 70%, 50%, 30%, etc. As a result of repeated research to solve the above problems, the present inventors found that, for example, sucrose fatty acid esters with a high monoester content of 70%, sucrose fatty acid esters with a low monoester content of 50%. Since it creates a sucrose fatty acid ester aggregate with a lower molecular weight than that of the sucrose fatty acid ester aggregate, the microscopic diameter of the aggregate is correspondingly smaller. It passes through the membrane more easily than 50% sucrose fatty acid ester, and therefore passes through the membrane together with unreacted sugars, by-product salts from the catalyst (formed when the catalyst is neutralized with acid), etc. I learned that I have an undesirable tendency to easily do this. Therefore, as an additional countermeasure, the present inventors proposed that monoester-containing fiL
unreacted sugar from highly impure sucrose fat 1υj acid ester,
If you want to remove catalyst-derived salts, etc., it is better to select a cancer membrane with a small molecular weight cutoff (i.e., small pore size), and conversely, in the case of sucrose fatty acid esters with a low monoester content, , it! has a large molecular weight cutoff (i.e., a large pore size)! It has been found that it is advantageous to select a membrane with a diaphragm in order to speed up the processing speed. Note that the inventors found that among the substances contained in the reaction mixture, unreacted fatty acid methyl ester, soap, and fatty acid were encapsulated in a micelle structure aggregate of sucrose fatty acid ester. It was also confirmed from the results of many experiments that it is practically impossible to separate sucrose fatty acid esters and their champions by cancerous methods because of the presence of sucrose fatty acid esters. Thus, from many experiments, the conclusion was that the impurities that can pass together with water through a filter membrane (having an appropriate molecular weight cutoff) using pressure as a driving source are unreacted sugars, salts derived from catalysts, and The substances that are incorporated into the high molecular weight micelle aggregates and cannot pass through the filtration stage are sucrose fatty acid esters, unreacted fatty acid methyl esters, soap, and M-separated salts. fatty acids, etc. The inventor of the present invention cleverly utilizes these 21 lists.
By selecting a filtration membrane with an appropriate molecular fraction,
This method successfully separated and removed unreacted sugar, catalyst-derived salt, and added neutral salt from the surroundings of sucrose fatty acid ester, unreacted fatty acid methyl ester, soap, and fatty acid. . (b-2 Molecular properties of cancer hypertarget substance) Limit I with an appropriate molecular weight cutoff! ! In order to select a membrane, it is necessary to know the approximate molecular weight of the target substance.The molecular properties of these single substances related to the invention are as follows. O sucrose = 342 0 Unreacted fatty acid methyl ester Stearic acid methyl ester = 290 0 When using hydrochloric acid generated by neutralization of catalyst (ToCO3) → Potassium lactate = 128 When using acetic acid → fA potassium acid = 980 addition In the case of neutral salt salt = 58.5 In the case of Glauber's salt = 142 0 Sucrose fatty acid ester (rl that does not form micelle aggregates)
(as mer) Sucrose monostearate = 600 Sucrose 1 distearate = 958 Sucrose tristearate = 11fl Note that there is no great difference in molecule 111 for other fatty acid esters such as myristate, palmitate arachinate, and behenate. O Soap Sodium Stearate - 298 Potassium Stearate = 314 O Fatty Acid Stearic Acid = 276 O Wood = 18 By the way, the apparent molecular weight of the aggregate of the micelle structure of the Sea I sugar fatty acid ester (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 As 100%, ◇A molecule of monoester 4i (Goo)X10
=8,000 Assuming 100% diester, ◇Minute 1' of diester single star - star (950)! 10=
8,580 triester As 100%, 0) ') x SteAyr7) Molecule j4(1,11
8) XlO=11,160. 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-3 Molecular weight cutoff of filtering membrane) A membrane suitable for the purpose of the invention is selected as follows. First, in a case where the molecular weight cut-off is 200, the reaction mixture in an aqueous solution state is supplied to the water film under pressure, and the salt generated from the unreacted sugar and the catalyst (x2co3) and the added neutral salt are removed. Even if the aim is to remove K2 COz, the only things that can be separated by the crying membrane are wood with a molecular weight lower than the molecular weight cutoff of 200 of the crying membrane, salts generated from the catalyst (K2 COz), and added neutral salts. Only. Fractional molecule Q Molecules larger than 200;
unreacted sugar cannot be separated and removed from sucrose fatty acid ester. Next, if the molecular weight cutoff is 5,000, the sucrose and the salt from the catalyst each have a molecular weight smaller than 5.000, so I)! It can easily pass through the micropores of the 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 e,ooo or more. Therefore. If the fractional molecule J4 of the diseased membrane is larger than 5,000, it is presumed that the micelle aggregate cannot pass through the micropores.
This JI constant has been experimentally confirmed. Finally, we also examined the case of a membrane with a fractionated molecule Qf of 1,000 in Test 3.I.
However, the results were as expected. In this way, by appropriately selecting the molecular weight cutoff of the membrane, it is possible to remove impurities including unreacted sugars from the sucrose fatty acid ester reaction mixture. (b-4 Conditions that should be met by the filtration membrane) The unreacted particles contained in the sucrose fatty acid ester reaction mixture, the salt by-produced from the catalyst (X2CO3), and the added neutral salt are removed by sucrose. When trying to separate fatty acid esters, stone parts, unreacted fatty acid methyl esters, and fatty acids from the west station, 11! The conditions that the membrane must meet are: (1) If the membrane has a certain molecular weight cut-off, it must be resistant to external physical forces. ■ Must be heat resistant and not decomposed by microorganisms. (Appropriate fractionation molecules have a high processing capacity. ■ It has a long service life. ■ It must be available at an economical price.) There has been significant progress, and as will be described later, even published materials can be found that satisfy the following conditions. (B-5 Practical Excessive Limitations) The composition is Oe, 15% to 95% sucrose fatty acid ester, 1% to 80% unreacted sugar.
%, unreacted fatty acid methyl ester 0.5% to 10%, catalyst (K2co:+) 0.05% to 7%, soap 2% to 8
0%, and fatty acid content is within the range of 0.5 to 10%. A reaction mixture of this composition contains unreacted sugar, catalyst (K2CO3
) and the salt produced from the neutralization of alcohol and the added neutralizer by ultrafiltration, the fatty acid methyl ester in the reaction mixture has a carbon number CI6 to The sucrose fatty acid ester of C22 and derived therefrom is preferably saturated.As a catalyst for sucrose fatty acid ester synthesis,
Potassium carbonate (K2 CO3) is typical, but catalysts used in general alcoholysis reactions, such as charcoal% sodium and sodium alkoxide, can also be used. 6. The type of fatty acid may correspond to the above-mentioned fatty acid methyl ester. When carrying out the present invention, water containing a neutral group is added to the water medium V, the sucrose fatty acid ester reaction mixture to be synthesized.
Ice: reaction mixture = 5:1 to 40:1 (weight ratio), more preferably water: reaction mixture = 20: 1
(weight j11 ratio), add 1 □ 1 cup and dissolve. Sucrose fatty acid esters are easily hydrolyzed in alkaline conditions, so to prevent hydrolysis, the pH of the solution should be adjusted to 6.
．． Adjust to 5-8.0. Next, as the monolithic salt that should be added, for example, sodium lactate, sodium butyrate, common salt, and nitrate are used, approximately 2% to 10%
% of the aqueous solution is suitable. If you do this,
A portion of the sucrose fatty acid ester dissolves, but a large proportion of the SE precipitates. After separating the precipitate cake, adding water to the precipitate cake and heating as necessary to obtain SE in a dissolved state, impurities are removed by keeping it at around 50°C and passing it through ultrafiltration. . The inventors have found that maximum filtration rates are obtained when the temperature is particularly within the temperature range of 40-80°C. That is, the filtration temperature is 40 to 60°C, optimally about 50°C.
By adjusting the temperature to around the same temperature, unreacted sugar,
Salt from K2O2+) and added neutral salts are most effective with water: (l) pass through the filter membrane well.The reason for this is that at 40-60°C As a result of the molecules of the ester micelle aggregates becoming larger, the total number of micelle aggregates decreases, making it difficult for substances that are not originally involved in the formation of micelle aggregates, such as unreacted sugars, to resist the sucrose fatty acid ester. This is presumed to be due to the fact that the unreacted side etc. can pass through more easily.As is known, sucrose fatty acid ester aqueous solution generally has a
It shows the maximum viscosity between eo' and c (cited above, p. 103), which suggests that it can have the largest molecule -jIl within that temperature range, and from this barium. , 4
This explains why the unreacted side shows the highest passing speed in the range of 0 to 60°C. Thus, the aqueous reaction mixture solution containing sucrose fatty acid ester maintained at 40-60°C was pumped for 1-2 times.
Pressure is applied as a driving source to 0 Kg/cm'G and brought into contact with ultrafiltration 1 in a hydrogen ion degree C range of pH 8.5 to 8.0. Cellulose-based filters are not only physically weak but also easily attacked by microorganisms, so they are not very desirable in practice. Practically preferred are membranes made of polysulfone or polyvinylidene fluoride reinforced with a support layer. Both of these types of filtration membranes are currently commercially available, and are excellent in heat resistance, alcohol resistance, and alkali resistance, and are resistant to external physical forces, and furthermore, microorganisms do not grow on the membrane surface. As mentioned above, when determining the separation between the two molecules of the filtration membrane, select a membrane that can efficiently separate the unreacted side without leaking sucrose fatty acid ester and has a high filtration rate. is important. The inventors found that as a result of Test 1) and 1, there was no leakage of sucrose fatty acid ester, and there was no reaction on the unreacted side, Ji! Rj's hope is that the separation performance is not impaired and the filtration rate is high! The 11Q fraction molecule +'Ii that satisfies 1- is preferably within the range of 1,000 to 100,000, and in particular, it can be used without omitting sucrose fatty acid ester and on an industrial scale. 1 fraction of molecules suitable for processing, 15,000 fractions of 1
I have found that 1 is the most preferred. 5,000,
As a result of the TFL filtration, sucrose fatty acid ester leaks, albeit slightly, due to the tfl filtration, and conversely, with a membrane having a fraction of less than 5,000 molecules of 111, 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 commercially available filtration membranes, one suitable for the purpose of the invention is 1. 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. Above I! ! Transmembrane <<TERP-HF-10>> (
According to the ultrafiltration membrane with fractional molecules J1) = 10,000), an aqueous solution (p) of the sucrose fatty acid ester reaction mixture! −
7.5), when the composition of the aqueous solution is as shown in Table 1 below, the separation rate on the unreacted side when the temperature is 50°C and the driving pressure is increased to 5.0 Kg/crn'G is as follows: 'Ultrafiltration 1 ton! 2 (1 unit?.) reached 5.0 Kg/sugar/hour. This is an industrially sufficient separation rate. Moreover, the rate of separation of the salt by-product from the catalyst was also sufficient. Incidentally, since the removal rate of unreacted salts, salts from the catalyst, and added neutral salts can be sufficiently increased by changing the number of times AfI passes through the filtration membrane, the unrecovered product is extremely advantageous for industrialization. The compositions of the reaction mixture and its aqueous solution are shown in Table 1 below. (Left below) Table 1 As described above, by using an ultrafiltration membrane, it is possible to easily extract the unreacted side from the sucrose fatty acid ester reaction mixture on an industrial scale.
! It becomes possible to remove the salt from L (K2CO:+) and the added neutral salt together with water,
Thus, the objective of removing unreacted sides and salts is achieved using only water and without using any solvent. (C reverse osmosis) The residual liquid (sucrose fatty acid ester, unreacted fatty acid methyl ester, The composition of the aqueous solution (containing a mixture of fatty acids) is approximately 1
% to 4% and moisture content is often in the range of 93% to 96%. Therefore, it is clear that if left as is, the energy cost for dehydration to obtain sucrose fatty acid ester would be excessive. However, as a result of research, the present inventors have found that the use of reverse osmosis membranes enables extremely low-cost dehydration and ELII, and that the above-mentioned problems can be solved industrially. The conditions that the reverse osmosis membrane used here must meet are: ■ It must be able to permeate only water from the aqueous solution that has passed the limit, ■ It must not deteriorate due to the growth of bacteria, ■ It must be heat resistant and alkali resistant. ■ It has excellent water removal ability, ■ It has a long service life, and as a result of research, the present inventors have found that in particular, a polyether membrane is reinforced with a polysulfone support.
It has been found that a reverse osmosis membrane made of a so-called composite membrane and having a fractional molecule rI'c of 60 is suitable. An example of a publication suitable for this purpose is <<PEC: 1000), which is being sold temporarily by Toshi Engineering Co., Ltd. For the above reverse osmosis membrane, preset the temperature 40°C to 60°C1pH.
When the aqueous solution to be treated, which has been adjusted within the range of 6.2 to 8.2, is brought into contact under a pressure of 7 g, effective dehydration can be achieved. At this time, if the pH is less than El, 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 the pH exceeds 8.3, fatal hydrolysis of sucrose fatty acid esters will occur, so it should not be made more alkaline than this.Furthermore, if the temperature drops below 40, water molecules will undergo reverse osmosis. The rate of passage through the pores of the membrane decreases rapidly. On the other hand, 60″
If you get C or higher, 4! Hydrolysis of the sucrose fatty acid esters when subjected to long-term reverse osmosis is a concern and should also be avoided. In addition, these 40~
The preferred operating condition of 60°C is also a condition discovered by the inventors11), similar to the above-mentioned ultrafiltration temperature. The pressure as a driving source is industrially preferably 50 to 9
5kg/cm7G. Under these conditions, the approximate wood removal rate is 0.06~0.
6 kg water/min, which is a large value on an industrial scale. Under the above preferred conditions, the aqueous solution containing the mixture of the above-mentioned enclosures is dehydrated and has a water content of 60 to 96%.
%, solid content = 40 to 4%. Note 6
In fact, by using a concentration method other than a reverse osmosis membrane, such as evaporation concentration under vacuum, it is possible to concentrate to a higher concentration than the above values. By doing so, for example, the next step of drying can be carried out economically.

[Effect] When wood containing neutral salts is added to the water-borne method sucrose fatty acid ester synthesis reaction mixture, which contains sucrose fatty ester, unreacted sucrose, unreacted fatty acid methyl ester, catalyst, stone base, fatty acids, etc. , crude sucrose fatty acid ester precipitates into a cake-like form. When this precipitate cake is dissolved in water and ultrafiltered, unreacted sucrose, salts generated from the catalyst, and added neutral salts pass through the ultrafiltration membrane together with water. By dehydrating the remaining liquid by reverse osmosis, concentrating it, and making it into a slurry, it is possible to economically purify the crude sucrose-fatty acid reaction mixture without using any solvent other than wood. (Margin below) 【Example】

Hereinafter, the manner and effect of implementing the invention will be explained with reference to Examples, but the examples are for illustrative purposes only and are not intended to limit the connotation or extension of the idea of the invention. Potassium carbonate (K2CO3) and sodium stearate were added to an aqueous mixture of stearic acid methyl ester and sucrose, and transesterification was carried out under vacuum while heating according to Hatake '7): C microemulsion method). A reaction mixture having the following composition was obtained. Table-2 After that, 4.300 kg of 3% dietary J11 water was added and 50°
When the mixture was stirred at C for 50 minutes, a white precipitate was deposited in the form of a cake. The precipitate cake was broken down and dissolved in 50°C water. The above aqueous solution was transferred to a spiral no. 'The liquid was sent to the cylindrical unit.The operating conditions at this time were: Delivery pressure = 9.5kg/c+a2G ~10.2kg
/c++12G liquid feeding temperature = 53.0°C to 53.5°C Solid content concentration in liquid = 5.3% Adjust 100 kg of the reaction mixture above to pH 7.3 with hydrochloric acid (blank below) Table 3 From the start of liquid feeding After 9 hours, 55.0% of the unreacted sugars originally contained in the anti-+5 mixture were removed into the permeate (iti liquid). On the other hand, there is no grain in the permeate! J'j
Leakage of IJtf rib acid ester was slight. Also byproduct i! l and added jE, 57.0% of them are permeate [
1 bow was removed. As a result of the above operations, the amount of liquid of the reaction mixture that did not pass through the filtration membrane and was condensed was approximately 2,000 kg, and on the other hand, 11!
The star of the cancer fluid that passed through the membrane was 2,400k. Next, this e-condensed liquid 2,000 kg L:, again 2,2
00kg (7) Add deionized water and heat at 50°C for 50
Stir for a minute to dissolve, re-adjust pH to 7.8, il! After adjusting the temperature, it was again fed to the above-mentioned filtration membrane. When the operation was carried out under approximately the same conditions as described above, 1,560 kg of concentrated liquid was discharged after 9 hours of one liquid passage. This C
The composition of the condensed liquid is shown in Table 3 below, and 90% of the target sucrose stearate was recovered, as well as unreacted t11! It was found that 75% of the particles were removed. However, unreacted methyl stearate, stearic acid, and stearate salts were not removed because they accompanied the sucrose stearate. Next, add 10 kg of the above recondensation liquid to a reverse osmosis membrane (product name (PE100
0 )) Molecular weight cutoff = 60) Membrane area 8rn'
was supplied to a spiral-shaped cylindrical unit at a temperature of 50°C. The operating conditions at this time are sending pressure = 57kg/c+e'G ~ 59kg/cm2
pH of G solution = 7.8 Table 4 After 7 hours, the amount of concentrated liquid concentrated by reverse osmosis membrane is 700k
g (calculated amount of sick liquid was 810 kg), and the composition of this concentrated liquid was as shown in Table 4 below. Margins below C) were rare. In this way, it has been found that approximately l' ii3 of the wood in the e-condensed liquid can be removed through the reverse osmosis membrane.

【Effect of the invention】

As explained above, the method for purifying sucrose fatty acid ester according to the present invention cleverly combines salting out of sucrose fatty acid ester with water containing neutral salts, ultrafiltration for salting out precipitation, and reverse osmosis. As a result, it is possible to provide a technology for economically producing highly pure sucrose fatty acid esters without using any organic solvent, and this technology has great industrial value. The advantages of the present invention are listed below for reference: (1) Sucrose fatty acid esters can be purified using inexpensive water without using any solvents in either synthesis or purification. ■ Since no organic solvent is used, there is no need for expensive explosion-proof gas equipment. (■ Since no organic solvent is used, there is no possibility of explosion or fire caused by the solvent. (4) Since no organic solvent is used, there is no risk of the solvent getting mixed into the product. ■) No organic solvent is used. Because it is not used, there is no adverse health effect on employees due to solvent vapor.・6) It is extremely easy to create an industrial-scale plant for the reasons listed in F. ■ It is possible to create a safe and low-cost plant. Patent applicant Daiichi Kogyo Seiyaku Co., Ltd.

Claims (1)

[Claims] 1. In addition to sucrose fatty acid ester, a neutral salt is added to the aqueous method sucrose fatty acid ester synthesis reaction mixture containing unreacted sucrose, unreacted fatty acid methyl ester, catalyst, soap, fatty acid, etc. After adding water containing and dissolving the resulting precipitate cake in water,
Contact with an ultrafiltration membrane to separate unreacted sucrose and salt by permeating the membrane together with water to produce an aqueous solution containing the remaining sucrose fatty acid ester, unreacted fatty acid methyl ester, soap, and fatty acid. A method for purifying sucrose fatty acid ester, comprising concentrating it by contacting it with a reverse osmosis membrane. 2 The composition of the reaction mixture is: Unreacted sucrose = 1-80% Unreacted fatty acid methyl ester = 0.5-10% Catalyst (as K_2CO_3) = 0.05-7% Soap = 2-60% Fatty acid = 0. The purification method according to claim 1, wherein the amount of sucrose fatty acid ester is 15 to 95%. 3. The purification method according to claim 1, wherein the water added to the sucrose fatty acid ester-containing reaction mixture contains a neutral salt of an acid selected from lactic acid, acetic acid, sulfuric acid, and hydrochloric acid. 4 The temperature of the aqueous solution of the sucrose fatty acid ester-containing reaction mixture is 40 to 60°C, and the amount of water added to it is water/
The purification method according to claim 1, wherein the amount is such that the reaction mixture = 5 to 40 (weight ratio). 5 The ultrafiltration membrane is composed of polysulfone-based or polyvinylidene fluoride-based resin, and has a molecular weight cut-off of 1.0
The purification method according to claim 1, wherein the purification method is from 00 to 100,000. 6. The purification method according to claim 1, wherein the pressure during ultrafiltration is 1 to 20 kg/cm^2. 7. The fatty acid residue constituting the fatty acid methyl ester has 16 to 22 carbon atoms, and the fatty acid residues of the soap and fatty acid are the same as the fatty acid residue constituting the fatty acid methyl ester, or 2. The purification method described in 2. 8. The purification 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. 9. The purification method according to claim 1 or 9, wherein the pressure during reverse osmosis is 50 to 65 kg/cm^2G. 10. The purification method according to claim 1, wherein the reverse osmosis membrane retentate is concentrated and made into a slurry.