JPS584038B2 - Shionoto Shibo Sunester No Kai Shuhou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for recovering sucrose fatty acid esters, and more specifically, the present invention relates to a method for recovering sucrose fatty acid esters, and more specifically, heating a liquid mixture containing sucrose fatty acid esters, water, and/or a solvent under reduced pressure to recover sucrose fatty acid esters. The present invention relates to an improvement in a method for recovering sucrose fatty acid ester by separating it into gaseous water and/or a solvent.

Sucrose fatty acid esters are gaining importance as tasteless and odorless edible surfactants.

In addition, sucrose fatty acid esters are highly biodegradable by microorganisms, so they are attracting attention as detergents that do not pollute the environment.

Conventionally, sucrose fatty acid esters have been produced by transesterifying sucrose and lower alcohol fatty acid esters in a solvent such as dimethylformamide or dimethyl sulfoxide in the presence of an alkali catalyst (Tokuko Showa). 35-13102), or a method of transesterifying sucrose and a fatty acid ester of a lower alcohol in a propylene glycol solvent in the presence of stone powder and an alkali catalyst (Japanese Patent Publication No. 4)
5-23534) and the like are known.

The reaction mixture obtained by the above method contains a solvent, unreacted sucrose, soap, a catalyst, etc. in addition to the sucrose fatty acid ester.

To separate the sucrose fatty acid ester from this mixture,
Usually, the reaction mixture is treated with a mineral or organic acid to neutralize and deactivate the catalyst, and then the solvent is partially distilled, followed by a hydrophobic organic solvent such as hexane, phthyl alcohol, methyl ethyl ketone, methyl isobutyl ketone, etc. Extraction treatment is carried out using water, and the liquids are separated by transferring mainly sucrose fatty acid ester into an organic solvent phase and mainly unreacted sucrose into an aqueous phase, and separating the liquid from an organic solvent phase containing mainly sucrose fatty acid ester. A method is adopted in which the organic solvent is removed by distillation and the sucrose fatty acid ester is recovered.

The organic solvent phase containing the sucrose fatty acid ester originates from the above-described separation step, and contains water, a small amount of unreacted sucrose, etc. in addition to the sucrose fatty acid ester and the organic solvent.

When recovering sucrose fatty acid ester from such an organic solvent phase, since sucrose fatty acid ester is thermally unstable and has the property of foaming, it is necessary to recover the sucrose fatty acid ester from the organic solvent by conventional separation such as distillation. Although it is possible to remove water and/or water, further removal may lead to decomposition of the sucrose fatty acid ester, making industrially satisfactory separation difficult. A viscous liquid substance (hereinafter referred to as liquid mixture) containing the sugar fatty acid ester and water and/or organic solvent remains.

The so-called rapid evaporation method is known as a general method for evaporating and concentrating liquid mixtures containing such thermally unstable substances. A horizontal thin film evaporator, for example, the Hitachi Konteguchi (manufactured by Hitachi, Ltd.), is known, which has a rotating shaft with a taper and straight blades parallel to the shaft.

When this evaporator was used to concentrate the liquid mixture described above, the amount of retention in the evaporator increased abnormally, reducing the concentration efficiency, and sucrose fatty acid esters adhered to the blades.
Carbonization occurred and the plant became stable [but operation was difficult.

As a result of studies to solve the above-mentioned drawbacks, the inventors of the present invention found that
By installing the straight blades at an angle with respect to the rotation axis, it is possible to prevent an increase in the amount of saccharide fatty acid ester retained in the evaporator, and as a result, the concentration efficiency does not decrease and the impact on the blades is reduced. The present invention was achieved based on the finding that stable operation is possible without adhesion and carbonization of sugar fatty acid esters.

That is, the present invention rotates a liquid mixture containing a sucrose fatty acid ester and water and/or an organic solvent by using a rotating shaft having a taper that gradually decreases from the inlet to the outlet and having straight blades that are inclined with respect to the shaft. The sucrose fatty acid ester and the gaseous water and/or organic solvent are separated and discharged from the outlet by supplying the ester from the inlet of a horizontal thin film evaporator, rotating the straight blades toward the outlet so as to generate a thrust. This is a method for recovering sucrose fatty acid esters.

The sucrose fatty acid ester targeted by the present invention includes, for example, sucrose and a carbon number 6 which may have a hydroxyl group.
Mention may be made of esters with saturated or unsaturated aliphatic carboxylic acids having up to 22 carboxylic acids.

Specific examples of the above aliphatic carboxylic acids include caprylic acid, cabric acid, lauric acid, myristic acid, palmitic acid, stearic acid, 12-hydroxystearic acid, △9・10
-totecylenic acid, halumitoleic acid, oleic acid, wasinoleic acid, linoleic acid, linolenic acid, etc., singly or in mixtures, etc., and sucrose fatty acid esters are sucrose fatty acid esters in which these aliphatic carboxylic acids have 1 to 8 hydroxy groups of sucrose. It is a mixture of one or more types of ester bonded with.

The liquid mixture treated by the method of the present invention is mainly produced by extracting the reaction mixture from the production of the sucrose fatty acid ester using a hydrophobic organic solvent and water according to the method described above, and removing the aqueous phase from the sucrose. It refers to a viscous liquid mixture obtained by removing the organic solvent and/or water from the organic solvent phase containing fatty acid ester by a conventional method, and usually contains sucrose fatty acid ester and water and/or organic solvent. All similar compositions apply to the present invention.

The horizontal thin film evaporator applied to the present invention has a taper that gradually decreases from the inlet to the exit direction of the liquid, and has a rotating shaft with straight blades inclined with respect to the axis, and the inclination angle of the inclined blade is Although it differs slightly depending on the fluidity of the liquid mixture, 2 to 9 degrees is usually suitable.

Next, a case in which the present invention is implemented using the apparatus shown in FIGS. 1 and 2 will be specifically described.

FIG. 1 is a schematic vertical cross-sectional view of a horizontal thin film evaporator used in the present invention, and FIG. 2 is a schematic cross-sectional view taken along line AA in FIG.

In FIGS. 1 and 2, the evaporator main body has a jacket 1 on the outside and is heated by a steam inlet 2 and a steam outlet 3, and the inside of the system is maintained under reduced pressure.

The rotating shaft 4 and the straight blades 5 are rotated in the direction of the arrow shown in FIG. 2 by a suitable drive (not shown).

The straight blades 5 are inclined at 6 degrees with respect to the axial direction of the rotating shaft 4.

The number of straight blades is not particularly limited, but 4 to 6 is usually appropriate.

The liquid mixture is introduced from the inlet 6, heated and concentrated under reduced pressure in the form of a thin film by the clearance 7 between the heating surface and the blade, and the sucrose fatty acid ester is separated from the gaseous water and/or organic solvent, and each is discharged. It is discharged from outlet 8.

The sucrose fatty acid ester discharged from the discharge port is cooled and then pulverized as desired.

On the other hand, gaseous water and/or organic solvents are recovered and reused.

In the accompanying drawings, the sucrose fatty acid ester and the gas are discharged from the same discharge port 8, but it goes without saying that they may be discharged from separate discharge ports.

When concentrating a liquid mixture using a horizontal thin film evaporator with a rotary shaft with straight blades inclined to the rotation axis according to the method of the invention, a conventional rotary thin film evaporator with straight blades parallel to the rotation axis is used. When using a horizontal thin film evaporator with a shaft, the above-mentioned problems such as abnormal accumulation of contents within the evaporator system, resulting in carbonization of the contents, and inability to discharge the contents do not occur at all, and the system is extremely smooth. Continuous concentration and drying of liquid mixtures can be carried out.

The reason for this is not necessarily clear, but in the commonly used horizontal thin film evaporator with straight blades parallel to the rotation axis,
The liquid moves toward the side with a larger rotation radius, creating so-called back pressure.
A sufficient amount of concentrated liquid is retained to compensate for this back pressure.

This retention increases abnormally with substances that exhibit difficulty in flowing, such as sucrose fatty acid esters, and dry matter adheres to the blades.
Causes burning.

In this case, tilting the straight blades is considered to be effective in draining the abnormally accumulated portion while maintaining normal accumulation due to back pressure.

Next, the method of the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the Examples described below.

In addition, the percentages described in the following examples and comparative examples are weight percentages.
means.

Example 1 A horizontal thin film evaporator (heat transfer area 10 m2) shown in Fig. 1 was used, the steam pressure in the heating section was 2 kg/cm2 gauge, the blade rotation speed was 200 rpm, and the clearance between the heat transfer surface and the blade was 2.5 mm. The inside of the evaporator is under reduced pressure of 80 mmHg,
When the liquid mixture shown below was passed through at 510 l/hour, no abnormal retention was observed in the evaporator, and the saccharide fatty acid ester with a solid content of 94% was continuously and smoothly discharged.

Composition of liquid mixture Sucrose fatty acid ester 44% sucrose
2% water
The above sucrose fatty acid ester is 70% monoester, 2 diester
and its fatty acid composition is 25% stearic acid, 70% palmitic acid and 5% myristic acid.

Comparative Example 1 Fig. 3 is a schematic vertical cross-sectional view of a horizontal thin film evaporator having a rotating shaft with straight blades parallel to the axis, and Fig. 4 is a schematic cross-sectional view taken along A'-A' in Fig. 3. .

On the outside of the evaporator body there is a jacket 1, which has a steam outlet 2 and an outlet 3.

The evaporator has a rotating shaft 4 connected to a suitable drive (not shown) for rotation, and straight blades 5 are mounted parallel to the axial direction of the rotating shaft.

6 is an inlet, 7 is a concentrate outlet, and 8 is a gas outlet.

Horizontal thin film evaporation products shown in Figures 3 and 4 (heat transfer area 1.
When the same liquid mixture as in Example 1 was passed under the same operating conditions using 0 m2), a large amount of abnormal retention occurred in the evaporator, and eventually the sucrose fatty acid ester was burned, and the sucrose fatty acid ester Evacuation of the ester was not possible.

Example 2 Using the horizontal thin film evaporator of Example 1, under the same operating conditions, a liquid mixture with the following composition was passed through at 600 tl-hour, and no abnormal retention was observed in the evaporator. Sucrose fatty acid ester with a solids content of 95% was discharged continuously and smoothly.

Composition of liquid composition Sucrose fatty acid ester 29% sucrose
1% water
The sucrose fatty acid ester is composed of 55% monoester, 30% diester and 25% human triester, and its fatty acid composition is 70% stearic acid, 25% palmitic acid,
Myristic acid is 5%.

Example 3 Using the horizontal thin film evaporator of Example 1, a liquid composition having the following composition was passed through at 660 l/hour under the same operating conditions.
Sucrose fatty acid ester with a solids content of 97% was discharged continuously and smoothly.

The sucrose fatty acid ester mentioned above is 35% monoester.
, and its fatty acid composition is 70% stearic acid, 25% palmitic acid and 5% myristic acid.

Examples 4 to 6 Using the horizontal thin film evaporator of Example 1, a liquid mixture having the composition shown in Table 2 was passed under the operating conditions shown in Table 1. The sucrose fatty acid esters having a solids content of 90% and in Example 6 90% were discharged continuously and smoothly.

Example 7 Using the thin film evaporator of Example 1, the heating section steam pressure was 2
kg/cm2 gauge, impeller rotation speed 200 rpm, clearance between heat transfer surface and impeller 2.5 mm, evaporator internal pressure 80 m
Under each mHg condition, 510 liters of a liquid mixture with the following composition was
The liquid was passed through the tank for several hours, and the sucrose fatty acid ester with a solid content of 95% was continuously and smoothly discharged.

Composition of liquid mixture Sucrose fatty acid ester 37% sucrose
5% water
The above-mentioned sucrose fatty acid ester consists of 75% monoester, 20% diester, and 5% triester, and its fatty acid composition is 0.9% caproic acid, 4.5% caprylic acid, and capric acid. 5
．． 3%, lauric acid 60.1%, myristic acid 18.6%
%, palmitic acid 7.4%, stearic acid 0.6% and oleic acid 2.5%.

[Brief explanation of the drawing]

FIG. 1 is a schematic vertical cross-sectional view of a horizontal thin film evaporator used in the present invention, and FIG. 2 is a schematic cross-sectional view taken along the line AA in FIG. FIG. 3 is a schematic vertical cross-sectional view of a conventional horizontal thin film evaporator, and FIG. 4 is a schematic cross-sectional view taken along line A'-A' in FIG. In Figures 1 to 4, 4: rotating shaft, 5: straight blade, 6: inlet, 8: outlet.

Claims (1)

[Claims] 1. A horizontal thin film that has a rotating shaft that has a taper that gradually decreases from the inlet to the outlet and that has straight blades that are inclined with respect to the axis, for transferring a liquid mixture containing a sucrose fatty acid ester, water, and/or an organic solvent. The sucrose fatty acid ester is supplied from the inlet of the evaporator, the straight blades are rotated to generate thrust toward the outlet, and the sucrose fatty acid ester and the gaseous water and/or organic solvent are separated and discharged from the outlet. A method for recovering sucrose fatty acid ester.