JPH01290690A - Method for removing volatile content in saccharide fatty acid ester producing reaction mixture - Google Patents

Abstract

PURPOSE:To readily remove a reaction solvent transferred to water phase and simultaneously recover total amount of saccharide fatty acid ester produced without using a solvent for purification by applying a specific treatment to a saccharide fatty acid producing reaction mixture. CONSTITUTION:An acid is added to a saccharide fatty acid ester producing reaction mixture containing an unreacted fattty acid methyl ester, catalyst, soap, fatty acid and volatile content to adjust pH to neutral region, preferably 7.5 and simultaneously water, neutral salt (preferably common salt) and saccha ride are added thereto. Then the mixture is heated to transfer the volatile content to water phase side and simujltaneously precipitate containing saccharide fatty acid ester, unreacted fatty acid methyl ester, soap and fatty acid is deposited. Finally, the above-mentioned precipitate is fractionated from water phase to complete removal of the volatile content.

Description

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

The present invention relates to a method for industrially removing volatile components (reaction solvent) in a reaction mixture containing a sucrose fatty acid ester without using a solvent when producing a crude sucrose fatty acid ester synthesized by a solvent method.゛

[Conventional technology]

Today, fatty acid esters (hereinafter sometimes abbreviated as "SE's"), which are widely used as useful ionic surfactants, are currently produced by (a) Z4 sugars in a molten mixture with fatty acid soaps in the presence of water; , a method of reacting with higher fatty acid methyl ester in the presence of a catalyst (aqueous method: Special Publication Showa 5l)
-14485) and (b) A method of reacting sucrose with higher fatty acid methyl ester using a solvent such as dimethylformamide or dimethyl sulfoxide (solvent method: Japanese Patent Publication No. 35
-13102). Of these two methods, the former (a) method does not cause solvent problems, but in the case of high-purity SE type production required as a carrier additive, method (b) eliminates the volatile matter remaining in the reaction mixture. In other words, the problem is the removal of the residual reaction solvent. In recent years, regulations on this volatile matter (hereinafter referred to as "reaction solvent") have become stricter. For example, according to US FDA regulations, the residual reaction solvent (dimethyl sulfoxide) in SE is limited to 2 PP@ or less (Fed. ,Regist, ,51(214
), 40160-1). Conventionally, complicated operations have been required to remove reaction solvents such as dimethyl sulfoxide and dimethyl formamide from a single reaction mixture (SE, a mixture of stone ages, fatty acids, unreacted fatty acid methyl esters, unreacted sugars, catalysts, etc.). I needed it. For example, according to 1 representative Japanese Patent Application Laid-Open No. 51-29417, a mixed solution of water and a "purification solvent" (especially referred to as such to distinguish it from a reaction solvent) has a light liquid layer (upper layer) and an ejected liquid P:j The property of phase separation in the (lower layer) is utilized. That is, since the heavy liquid layer (lower layer) generally contains a large amount of water, hydrophilic unreacted sugars, catalyst-derived salts, etc. are dissolved in this m liquid layer (lower layer). On the other hand, since the light liquid layer (upper layer) contains a large amount of purified solvent, substances with low polarity 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 dissolve in the lower heavy liquid layer, but unfortunately they also dissolve in the upper light liquid layer, making it impossible to completely separate the reaction solvent using this method. It is. Therefore, a very large amount of purified solvent was required just for the purpose of removing trace amounts of reaction solvent. However, the heavy use of purified solvents causes the following difficulties, and this is because, although it may be small-scale, in factories that manufacture SE type on an industrial scale, the disadvantages and inconveniences caused by handling solvents are noticeable. It was something. ■ Risk of explosion or fire.・■ Explosion-proofing of electrical equipment in preparation for ■ above. ■ Seal the manufacturing neck 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 effects of residual solvent remaining in the product sucrose fatty acid ester. ■ Impact on employees' health, which in turn increases man-hours and costs. Under these circumstances, there has been a pressing need in the industry to develop a purification technique that makes it unnecessary to use a purification solvent during SE purification.

[Problem B that the invention attempts to solve]

The present invention aims to solve all the problems caused by the use of solvents by eliminating the use of organic solvents for purification during the purification of crude SH.

[Means to solve the problem]

In order to achieve the above objects, 1. the method of removing volatile matter from the sucrose fatty acid ester producing reaction mixture according to the present invention is to remove unreacted sugars, unreacted fatty acid methyl esters, unreacted fatty acid methyl esters, After adding an acid to the sucrose fatty acid ester production reaction mixture containing 50% (residual reaction solvent) and adjusting the pH to a neutral range, water, neutral salts and sucrose were added, and the mixture was heated to remove volatile components (remaining reaction solvent). is transferred to the aqueous phase side, and a precipitate containing sucrose fatty acid ester, unreacted fatty acid methyl ester, stone age, and fatty acid is precipitated, and the precipitate is separated from the hydrated one. (Progress of the Invention) The method of precipitating SE in a reaction mixture and separating it from woody substances such as unreacted sugars without using a purification solvent is known. Precipitation method of SH using aqueous solution (British Patent No. 8)
0!9,815 (1959) (2) A method of precipitation of SH using a general neutral salt aqueous solution (Japanese Patent Publication No. 42-8850) is known. However, if, for example, an aqueous hydrochloric acid solution is added to the reaction mixture as in method (1), SE will immediately precipitate, but unreacted J21 sugar will easily decompose and convert into glucose and fructose, even at low temperatures (0. Decomposition cannot be avoided even if the reaction is carried out at a temperature of ~5°C), making it difficult to recover and reuse unreacted sugar. Furthermore, even if an aqueous solution of a neutral salt such as monosalt or mirabilite is added to the reaction mixture as in method (2), SE will immediately precipitate. In this case, unreacted sugars do not decompose, but monoesters, which are useful components in SE, are dissolved in the aqueous layer, resulting in not only large losses but also especially high HL
It becomes a hindrance when you want to obtain SE of B. Therefore, the present inventor aimed to (a) not only minimize the amount of SE dissolved in the aqueous layer side, but also reduce the amount to zero if possible to precipitate the entire amount of SE, and (a) decompose unreacted sugars. As a result of conducting many salting-out experiments with the following three goals: (c) separating the residual reaction solvent from the SE by dissolving it outside the aqueous layer, we found that the relationship between tjtB and the neutral salt was When aqueous solutions of the two substances are dissolved in a reaction mixture, under appropriate combinations of F)I, temperature, concentration of neutral salt, concentration of sucrose, and amount of water, not only almost the entire amount of SE will precipitate. . Surprisingly, we discovered a convenient phenomenon in which the reaction solvent was dissolved in addition to the unreacted sugar in the aqueous phase. The present invention is based on the above novel findings. The details of one invention will be described below. (SE reaction mixture) In the synthesis of SE by the above solvent method, 1. Usually, several times the amount of reaction solvent 1, for example, dimethyl sulfoxide, is added and dissolved in a mixture of sucrose and fatty acid methyl ester, and the presence of an alkaline catalyst such as potassium carbonate. Vacuum 20-30 below
Hold at 80-80°C for several hours at around Torr. As a result, an SE reaction mixture is obtained with a reaction rate of 90% or more (based on fatty acid methyl ester).Next, in order to eliminate the activity of the alkaline catalyst in this reaction mixture, add a neutralizing amount of lactic acid, acetic acid, or other organic Add acid or mineral acids such as hydrochloric acid or sulfuric acid. This neutralization converts the catalyst, eg potassium carbonate, to the corresponding potassium salt of the acid, such as potassium lactate. Finally, one reaction solvent, such as dimethyl sulfoxide, is distilled off under vacuum, resulting in an SE reaction mixture having approximately the following composition. Sucrose fatty acid ester = 15-82z unreacted sugar
= 1.0 ~ 80% unreacted fatty acid methyl ester = 0.5 ~ 10% KzCCh O) Neutral salt = 0.05 ~ 7% soap
=1.0 ~10% fatty acid
=0.5 to 10% volatile content (residual reaction solvent) =
5.0 to 30% At this time, the ester distribution of SE is monoester 10 to 75% (diester or more is 80 to 25%
). In the present invention, each of the fatty acid methyl ester, stone age, and fatty acid mainly has a common saturated fatty acid root. Moreover, it is suitable when the number of carbon atoms is 16 to 22. (Addition of water) In the present invention, first, water is added to the above reaction mixture, and when the P)I is not within the range of 6.2 to 8.2,
The pH is adjusted within this range, preferably to pH 7.5. The amount of water to be added preferably corresponds to water:reaction mixture = 5:l to 40:1 (weight ratio), more preferably water:reaction mixture = 5:l to 20:1, as a ff1flL ratio. It's the amount. When the amount of water added is out of the above range 1 For example, when the ratio of water to reaction mixture is less than 5, the viscosity of the aqueous solution after adding water becomes excessive, making subsequent operations substantially difficult. On the other hand, if an excess of water is obtained such that the water:reaction mixture ratio is 40 or more, the viscosity decreases, making subsequent operations easier, and the desired reaction solvent can be removed well. However, this is not preferable because dehydration for recovering unreacted sugars and the like requires a large amount of energy cost. As mentioned above, the pH value of the target aqueous solution is preferably maintained within the neutral range of 6.2 to 8.2;
If it exceeds 2, there is a risk of quantitative decomposition of SE by alkali, and even if it is less than 6.2, there is a risk of acid decomposition if exposed to high temperatures of, for example, 90° C. or higher. (Addition of Neutral Salt and Sucrose) Next, a neutral salt and sucrose are added to the aqueous solution of the SE reaction mixture that has been hydrated (and pH adjusted!) as described above. At this time, the neutral salt to be added is preferably common salt, mirabilite, potassium lactate, or potassium acetate, but it is not limited to the exemplified salts as long as they are water-soluble and harmless. What is important is that the amount of neutral salt to be added in this case preferably first satisfies the following formula (3). =0.015~0.12 (weight ratio)・・・・・・■
Here, the total amount of salt = the salt formed from the neutral salt quantum catalyst to be added...■ The total amount of tI = the rA sugar to be added and the unreacted sugar present from the beginning...■. Next, the amount of sucrose to be added is preferably determined so as to satisfy the following formula (2). = 0.025 to 0.20 (weight ratio)...
- In addition to 0 or more, the ratio of total base amount to total sugar amount to be added according to the above formulas (1) and (2) is also 0.4 to 0.6°, more preferably 0.5°. That is, it is preferable that the following formula (2) be satisfied. The present inventors added an aqueous solution (containing SE precipitate) to the reaction mixture so as to satisfy all the formulas (1), (2), and (2) above at a temperature of 50°C to 80°C. When the system is heated and the temperature is raised, the SE present in the system is not substantially dissolved in the aqueous phase and almost all of it migrates to the precipitation side, while the volatile components (residual reaction solvent) are deposited in the aqueous phase. I found it to stay. This phenomenon is due to the fact that the amount of volatiles contained in the SE reaction mixture is
It is unique in that it is observed even when the variation is as large as 30%, thereby achieving the objective of removing volatiles without using purification solvents and without incurring loss of SH. The attached FIG. 1 illustrates the above phenomenon in more detail. In other words, this figure shows that the weight of SE dissolved in the aqueous phase M = Y [gl The weight of precipitated SE = X [gl Total SE (X + Y) [gl When the weight percentage of SE = φ [%], how the value of φ defined by the following formula ■ changes under the experimental conditions shown below can be expressed using triangular coordinates This is what is shown. [Experimental conditions] Temperature = 80°C, pH: 7.5 Water: Reaction mixture = 7.4:1' (weight ratio) [Composition of reaction mixture] Sucrose fatty acid ester - = 29! Unreacted sugar = 351 Unreacted fatty acid methyl ester: = 2z Catalyst-derived salt = 1z Soap
= 3% Fatty acid = tX volatile matter (residual reaction solvent) = 29X φ・[Composition of sucrose fatty acid ester] Seven esters =? 31 Diester or more = 27z
Here, the total salt is calculated by equation (2), and the total sugar is calculated by equation (3).
The amounts are respectively defined by , and are expressed as water + total salt and total sugar = 100. The shaded area in this figure is a preferred implementation area of the invention that simultaneously satisfies Formula 01 Formula (2) and Formula (2) found by the inventor. By determining the dissolved amounts of neutral salt and sucrose so that they fall within this oblique agA region, it is possible to substantially precipitate φ=0, that is, to precipitate approximately all of the SE, and at the same time, to precipitate the remaining SE in the aqueous phase. Volatile matter can be dissolved.

[Effect]

Unreacted sugar, unreacted fatty acid methyl ester. Catalyst 1 Acid is added to the reaction mixture containing soap, fatty acid, and volatile matter (residual reaction solvent) to form a fatty acid ester, the pH is adjusted to a neutral range, and water, neutral salt, and rMSS are added and heated, resulting in sucrose. Fatty acid ester. Unreacted fatty acid methyl ester, soap, and fatty acid are precipitated, and volatile components (residual reaction solvent) are transferred to the aqueous phase, so that residual volatile components can be removed without using any organic solvent. especially. By operating so as to satisfy the conditions of formulas (1) to (2), the residual solvent can be removed with virtually no loss of SE.

【Example】

Hereinafter, embodiments of the invention will be described with reference to Examples, but the examples are merely for illustration and are not intended to limit the technical aspects of the invention. Add 2,000 g of water to 100 g of a dry product obtained by neutralizing the residue obtained by distilling off the solvent in a conventional manner from the solvent method SE reaction mixture represented by the composition shown in Table A below with lactic acid, and stir. , After dissolving, 82.5 g of sucrose and 97.8 g of 50% potassium lactate were added to this aqueous solution, heated to 75 ° C.,
The precipitated cake was filtered off and dried under vacuum at 80°C. The composition of the obtained solid was as shown in Table B below. In addition, as a result of measuring SEI in the filtrate filtered from the cake by gel wave chromatography (see page 63 of Sugar Ester Monogatari, published by the applicant company), no SE was detected. 85% of the dimethyl sulfoxide present had been removed. Table-A # Ester content of SE 1 Monoester 70%, diester or more 30% (blank below) Table-B Example 2 The reaction solvent was distilled off from the solvent method SE reaction mixture represented by the composition of Attached Table-A in a conventional manner. After that, 2,000 g of water was added to 100 g of the solid material which was neutralized with lactic acid and dried, stirred and dissolved, and 28.5 g of sucrose was added to this aqueous solution. and 50% potassium lactate 65.8. was added and heated to 75°C. To this, the same operations as in Example 1 were added, and the table below-
A solid substance having the composition described in ○ was obtained. On the other hand, the amount of SE contained as a loss in the liquid separated from the cake was measured by gelatin hyperchromatography (see above).
When quantitatively determined, the loss of SE was 0.02 g (the initial amount was O, Off, but 95% of the dimethyl sulfoxide, which was the reaction solvent for the second reaction, was eluted into the aqueous phase. )

【Effect of the invention】

As explained above, the present invention does not use any organic solvent for purification in purifying crude sucrose fatty acid ester,
Moreover, by providing a technique for removing residual reaction solvent without loss of sucrose fatty acid ester, the present invention can contribute to related industries by solving all problems caused by the use of organic solvents.

[Brief explanation of the drawing]

The tjS1 diagram is a triangular graph showing the relationship between changes in the amounts of water, total sugar, and total salt and the amount of ff1L fatty acid ester dissolved in the aqueous phase. Patent applicant: Daiichi Kogyo Seiyaku Co., Ltd. - Shigosunshio (%)

Claims (1)

[Claims] 1. Add acid to a sucrose fatty acid ester producing reaction mixture containing unreacted sugar, unreacted fatty acid methyl ester, catalyst, soap, fatty acid and volatile components to adjust the pH to a neutral range, and add water to the reaction mixture. Add neutral salt and sucrose and heat to transfer volatile components to the aqueous phase, precipitate a precipitate containing sucrose fatty acid ester, unreacted fatty acid methyl ester, soap and fatty acids, and separate this from the aqueous phase. A method for removing volatile matter in a sucrose fatty acid ester producing reaction mixture. 2. The method according to claim 1, wherein the pH after adjustment is 6.2 to 8.2. 3 The heating temperature of the aqueous solution containing water, neutral salt and sucrose is 5.
The method according to claim 1, wherein the temperature is 0 to 80°C. 4. The process according to claim 1, wherein the weight ratio of water to be added to the reaction mixture is from 5:1 to 40:1 water:reaction mixture. 5 The ratio of salt, sugar, and water in an aqueous solution containing water, neutral salt, and sucrose is: Total salt/(Water + Total salt + Total sugar) = 0.015 to 0.1
2 and total sugar/(water + total salt + total sugar) = 0.025-0.2
0 and total salt/total sugar = 0.4 to 0.8 Total salt = neutral salt to be added + salt generated by neutralization of catalyst Total sugar = sucrose to be added + unreacted sugar from the beginning The method according to claim 1, comprising: 6. The method according to claim 1, wherein the acid used for pH adjustment is lactic acid, acetic acid, hydrochloric acid, or sulfuric acid. 7 The composition of the reaction mixture is: sucrose fatty acid ester = 15-92% unreacted sugar = 1.0-80% unreacted fatty acid methyl ester = 0.5-10% catalyst (K
_2CO_3) = 0.05~7% Soap = 1.0~
5. The method according to claim 1, wherein: 10% fatty acid = 0.5-10% volatile content (residual reaction solvent) = 5.0-30%. 8. The fatty acid radical according to claim 1, 4 or 7, wherein the fatty acid radicals mainly contained in each of the fatty acid methyl ester, soap, and fatty acid in the reaction mixture have a common saturated fatty acid radical and have a carbon number of 18 to 22. Method. 9. The method according to claim 1 or 7, wherein the volatile component (residual reaction solvent) in the reaction mixture is either dimethyl sulfoxide or dimethyl formamide. 10. The method according to claim 1 or 5, wherein the neutral salt to be added is any one of common salt, mirabilite, potassium lactate, or potassium acetate. 11. The ester distribution of sucrose fatty acid ester is 10% to 75% as monoester content (diester or more is 9
8. The method according to claim 1 or 7, wherein the amount is 0% to 25%).