JPH02152986A - Recovery of sucrose - Google Patents

Abstract

PURPOSE:To recover the subject compound in high yield by reacting sucrose with a fatty acid alkyl ester in a specific solvent, treating the resultant sucrose fatty acid ester solution, adding methyl isobutyl ketone to the treated solution and precipitating sucrose at a specific temperature, CONSTITUTION:Sucrose is made to react with a fatty acid alkyl ester in the presence of dimethyl sulfoxide (DMSO) as a solvent to obtain a sucrose fatty acid ester (SE). The SE-containing solution is distilled under reduced pressure to attain a DMSO content of 10-50wt.% (preferably 20-40wt.%) and mixed with 2-12 pts.wt. (preferably 4-10 pts.wt.) of methyl isobutyl ketone at 0-110 deg.C based on 1 pt.wt. of DMSO remaining in the solution. The precipitated sucrose is separated by filtration, Centrifugal separation, etc., and dried to recover the objective unreacted sucrose.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for recovering sucrose. Specifically, the present invention relates to dimethyl sulfoxide (hereinafter referred to as "DMSo").
It is abbreviated as ) as a solvent to produce a sucrose fatty acid ester, and then recover unreacted sucrose contained in the reaction product liquid.

[Conventional technology]

Sucrose fatty acid ester (hereinafter abbreviated as rSEJ) has excellent surfactant ability, good biodegradability, and high safety, so it has been used in foods, cosmetics, pharmaceuticals, kitchen detergents, feed, It is an extremely useful compound that is widely used as an additive in resins and the like, and as an auxiliary agent for reaction solutions in polymerization reactions, oxidation reactions, etc. in the chemical industry.

BACKGROUND ART Conventionally, there has been known a method of producing SE by using DMSO or dimethylformamide (hereinafter abbreviated as DMF) as a reaction solvent and reacting sucrose with a fatty acid alkyl ester.

In these methods, it is necessary to add an excessive amount of sucrose to the fatty acid ester to recover DMSO or, depending on the combination, the fatty acid ester.

Methods for recovering sucrose are classified into liquid-liquid extraction methods and solid-liquid extraction methods.

In the liquid-liquid extraction method, a solvent that completely dissolves SE and a solvent that completely dissolves sucrose are selected and processed. Alcohols such as isobutyl alcohol are used as the extraction solvent for SE, and water is used as the extraction solvent for sucrose. ing. In such a liquid-liquid extraction method, a portion of SE is transferred to the aqueous layer and a portion of sucrose is transferred to the organic layer, resulting in a decrease in the yield of SE and
Furthermore, since sucrose is recovered from the aqueous layer, a large amount of water must be removed from the recovered liquid.

On the other hand, the solid-liquid extraction method is a method in which a precipitation solvent that dissolves SE but not sucrose is added to the reaction product solution, sucrose is precipitated, and the precipitated sucrose is recovered.

In this case, an invention is known (Japanese Patent Publication No. 429.7) in which DMFi is used as a reaction solvent and an aromatic hydrocarbon such as benzene is used as a precipitation solvent.

Also, JP-A-63-27'7?7 and tJsP
J., 25 Otsu No. 29, DMS is used as a reaction solvent.
An invention is described in which O is used and methyl ethyl ketone (hereinafter abbreviated as MEK) is used as a precipitation solvent.

Also, USP, 3. /Gi, Oi Publications suggest a method in which DMFi is used as a reaction solvent and methyl isobutyl ketone (hereinafter abbreviated as MIBK) is used as a precipitation solvent.

[Problem to be solved by the invention]

However, in the above method using DMSO as the reaction solvent and MEKf as the precipitation solvent, M
EK has a low flash point of 1/C and a high vapor pressure even around room temperature, so solid-liquid extraction operations must almost always be carried out in a closed container.

Further, in some cases, heating is performed in order to transfer SE to the organic layer, but because MEK has a high vapor pressure, there are restrictions on the equipment and operations for carrying out the extraction. Furthermore, MEK has insufficient solubility for SE with a high degree of esterification, and the SE generated by the reaction
There were problems such as a difference in ester distribution between SE dissolved in methyl ethyl ketone and SE dissolved in methyl ethyl ketone.

On the other hand, in the method of using DMFi as the reaction solvent for No. 11 and MIBKe as the precipitation solvent, there was a problem in that the precipitated solid containing sucrose had poor P suitability, and separation could not be performed completely smoothly.

[Means to solve all divisions]

That is, in the present invention, sucrose and fatty acid alkyl ester are reacted using dimethyl sulfoxide as a solvent to produce sucrose fatty acid ester, and the resulting sucrose fatty acid ester production liquid is treated under reduced pressure to produce dimethyl sulfoxide. The content was distilled off until it reached the io-go weight ratio, and then methyl imbutyl ketone in an amount of ~72 times the weight of the remaining dimethyl sulfoxide was added to the resulting solution after distillation, and the mixture was heated at 0 to 110°C. This is a complete summary of a method for recovering 7-yose sugar, which is characterized by recovering sucrose that precipitates under temperature conditions.

In the present invention, the component ratio before the SE production reaction is approximately 50 to 0% by weight of DMSO, and 20 to 50% by weight of sucrose and fatty acid ester in total.
Most of the O content may be precipitated, but in that case a large amount of MIBK? It was also found that the recovery rate of sucrose was slightly reduced. In the present invention, DMSO in the reaction product liquid is distilled off by vacuum distillation to a specific range, specifically, the reaction product liquid is distilled under reduced pressure to reduce the DMSO content to about 70 to 50% by weight.
Preferably, the weight is adjusted to about 20-tio.

For the solution prepared in this way, the remaining DMSO
~12 times by weight, preferably q~10 times by weight of MIBK
and mix under Q~/10°C. The flash point of MIBK is 11°C, and sucrose recovery operations can be carried out in an open container at temperatures lower than this temperature. Usually, it is better to heat the organic layer in order to increase the amount of SE dissolved in the organic layer, and in that case, use a closed container.

MIBK can be operated at less than 7 & OrrmHl even at about /10°C, and in some cases it is possible to heat it to around that temperature to reduce the amount of MIBK used.

After adding and mixing MIBK, the precipitated sucrose is filtered, centrifuged, etc. to separate and collect the organic layer.

Most of the recovered solids are sucrose, but a small amount of D
Although MSO and SE also contain a small amount of MIBK, they may be reused as is or after drying to remove MIBK. Unlike the liquid-liquid extraction method, the present invention does not use water, so there is no need to perform a water removal operation that is disadvantageous in terms of energy.

When sucrose is recovered through the above-described operations, more than 50% of unreacted sucrose present in the product solution can be recovered.

According to the present invention, there is no restriction depending on the type of fatty acid group of SE, and it can be applied to any type of produced liquid after producing SE, and the ester distribution of SE dissolved in MIBK is the same as the state before treatment. Almost no change.

〔Example〕

EXAMPLES The present invention will be explained in more detail below with reference to Examples, but the present invention is not limited to the following Examples.

Example 1 DMSO 5-oo y, sucrose tstts were added to a flask 21 connected to a stirrer, thermometer, cooling tube, and pressure reducing device.
g, methyl stearate, toOfj'jr: Prepared, heated to 90ac at 20fiHg, held for about 7 hours to remove moisture contained in the raw material, then added 7.4-gi of potassium carbonate to it, and heated to 90℃. In, 2
The mixture was maintained under reduced pressure of 0 mH9 for 3 hours. Thereafter, the system was returned to normal pressure, cooled to approximately so"c, and neutralized by adding 10 g of an aqueous solution of !O weight of lactic acid. A portion of the produced liquid was extracted and analyzed, and methyl stearate was found. Not detected, DMSO concentration was approximately 72% by weight, sucrose 79%.
3% by weight, 5Eff, and 7% by weight. The ester distribution of SE was monoester/diester/triester=G'3/33/co2 (weight ratio).

These analyzes were performed using liquid chromatography and gas chromatography.

The product liquid λsog produced as above is 1t-y
The sample was placed in a lasco and treated with 90'C1/Om5H9 or less to remove a portion of the DMSO, resulting in 1001.

The composition of the concentrate is DMSOj/, /weight, sucrose,
5 was in charge of weight, and sE Kohachi was in charge of weight.

Add MIBK to this concentrate at room temperature (5°C).
When the mixture was stirred for i hours, allowed to stand, and filtered, a solid bo'jSP liquid was obtained. The content of sucrose in solid matter and pi is ψ6. ? The recovery rate of sucrose as a solid was 9 K. Incidentally, SE of t,, a g was detected in the solid, but the ester distribution was almost the same as that of sE in the F solution and the SE immediately after the reaction.

Example The same operation as in Example 1 was carried out at 50° C., and 55 g of solid matter and 939 g of liquid were obtained. The content of sucrose in the solid matter and liquid F is 4.71j, 0. g
i, and the recovery rate of sucrose as a solid is 7 go
, 1%.

In addition, SE of ko and og were detected in the solid matter, but SE
No change was observed in the ester distribution.

Example J MI B was added to 100'j of the concentrate obtained in the same manner as in Example 1.
When K ixu, a 9 (MI BK/DMSO weight ratio) was added and the same operation as in Example 1 was performed at 50°C, a solid substance was obtained! rty, F solution/btg was obtained. The content of sucrose in solid matter and F solution is tIg, respectively.
, r g, o, 'y g, and the recovery rate of sucrose as a solid carving was 5. In addition, 3.2
g of SE was detected, but no change was observed in the SE ester distribution.

Example q DMSO25θO was added to the same apparatus as described in Example/.
g, sucrose 22θ1, and methyl stearate 766 g were heated to 90°C under Owm H';
The mixture was held for about 1 hour to remove water contained in the raw materials. Next, 7.5 g of potassium carbonate was added, and the temperature was 0°C.
The reaction was carried out for 3 hours. After the reaction, the inside of the system was returned to normal pressure, cooled to about 5θ°C, and neutralized by adding lactic acid 5y1 (dissolved in 5 g of water).

When a part of the product liquid was extracted and analyzed, methyl stearate was not detected and the DMSO concentration was 73. Hiro weight%
The content was 3% by weight for sila sugar, and 3% by weight for S E 2s. ``Also, the ester distribution of SE is mono/di/tri/tetra/penta/hexa/hepta/octa = 0.'
l / /, 0 / /, J /2 gu, 6 / s
t,, t, / / gu, de/ / t, 0 /
, 2.9 (weight ratio).

The produced asoy produced as described above was placed in an IT flask and treated at 90°C and 10 mH (!) to DM.
A portion of SO was removed to give 1OOy. The composition of the concentrate is 0 MSO3,t, a wt%, sucrose 3.3 wt%, 5E
t was 3.3% by weight. Add this concentrate to room temperature (25°C).
Please add MIBKλsog under M I B K
/DMSO weight ratio q, s) was stirred for a time, allowed to stand, and filtered to obtain solid substance 109 and IP' liquid 31709.

The content of sucrose in the solid substance and liquid F is 3. Ko1, o,
ip, and the recovery rate of sucrose as a solid was 97.
It was 0%. Although 5.2 g of SE was detected in the solid matter, the ester distribution was almost the same as that of the SE in the F solution and the SE immediately after the reaction.

Comparative Example/Methyl ethyl ketone 250% was added to the concentrated SE-containing concentrate obtained in the same manner as in Example 1 at room temperature (25°C).
MEK/DMSO (weight ratio 1.2) was added to the apparatus, and after stirring for 1 hour, the solids were filtered. ! I got y. The contents of sucrose in the solid matter and the F solution are 2.99 and θ, respectively, and the recovery rate of sucrose as a solid matter is 7. He was very talented.

The ester distribution of SE in the P solution is mono/di/tri/tetra/penta/hexa/hepta/octa = 1.3
/ ko, λ / 2.6 / J tl, j / 3 ko,
57/J,,2/q,s/Il,o (weight ratio), which was 1, which was different from that immediately after the reaction.

COMPARATIVE EXAMPLE In an apparatus similar to that described in Example 1, dimethylformamide (DMF) 2! 009, sucrose A t 4
g, methyl stearate 3oog'i (preparation, ?j
The temperature was raised to 90° C. under mHg and held for about 1 hour to remove water contained in the raw materials. Next, add potassium carbonate, &g, deQ℃, ? The reaction was carried out for 3 hours under JIIIllHg.

After the reaction, the inside of the system was returned to normal pressure, cooled to about sθ°C, and neutralized by adding ioy, a 50% by weight solution of lactic acid.

When a part of the product liquid was extracted and analyzed, methyl stearate was not detected, and the DMF concentration was approximately 72, Hiroshi weight ratio, sucrose/3.1% by weight, and SE/G (.5% by weight). Also, the ester distribution of SE is monoester/diester/triester: j 2 / 30
/ / t (weight ratio).

The product solution produced as described above was placed in a flask of about 2,309 gold/L and treated at 90° C. and 9QIIIHg or less to remove a portion of DMF, resulting in a concentration of 100′J. The composition of the concentrate was DMF, 7/, (177% by weight, 32.7% by weight of sucrose, 34.3% by weight of 5E.
Add MIBK2t1g9 at 25°C ~ II
BK/DMF weight ratio t), after stirring for 1 hour, it was left to stand and filtered, 6 solids, 1 g, IP' liquid 2 g! ;,9
I got g. Note that the solid matter was sticky and required a long time to filter. The content of sucrose in the solid and p-liquid is 30, t! And eight? y, and the recovery rate of sucrose as a solid was q, flathead.

In addition, an SE of /0.31 was detected in the solid matter,
The ester distributions of SE in P solution and SE immediately after reaction were almost the same.

〔Effect of the invention〕

According to the present invention, unreacted sucrose present in the product solution can be recovered at a high rate.

Further, according to the present invention, there are no restrictions on the equipment and operation for performing the extraction, and furthermore, it can be applied to the product liquid after producing SE with a high degree of esterification, and it is also possible to apply it to the product liquid after producing SE with a high degree of esterification. The ester distribution of SE is almost unchanged from the state before treatment.

Furthermore, the transient nature of the precipitated solid containing sucrose is also good.

Claims (1)

[Claims] (1) Using dimethyl sulfoxide as a solvent, sucrose and fatty acid alkyl ester are reacted to produce sucrose fatty acid ester, and the resulting sucrose fatty acid ester production liquid is treated under reduced pressure to contain dimethyl sulfoxide. Dimethyl sulfoxide is distilled off until the amount becomes 10 to 50% by weight, and then 2 to 12% of dimethyl sulfoxide remaining in the resulting solution after distillation is
Add twice the weight of methyl isobutyl ketone and add 0 to 110
A sucrose recovery method characterized by recovering sucrose precipitated at a temperature of ℃.