JPS5932481B2 - Method for producing hydroxyalkylated polysaccharide - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing hydroxyalkylated polysaccharides from non-granular polysaccharides.

Non-granular polysaccharides are opposed to granular polysaccharides.

Granule-like polysaccharides are polysaccharides having granules with a diameter of about 1 to 100 microns.
Since granules are starch granules, granule-like polysaccharides refer to starches. On the other hand, non-granular polysaccharides refer to polysaccharides other than granular polysaccharides, and therefore are a general term for polysaccharides other than starches. Non-granular polysaccharides include polysaccharides that do not contain starch granules. Examples include cellulose and guar gum, and polysaccharides in the form of crushed starch, such as pregelatinized starch. Non-granular polysaccharides. It is generally an amorphous solid. In this invented method. Since the raw material is a non-granular polysaccharide, this will be referred to as the raw material polysaccharide hereinafter. Hydroxyalkylated polysaccharides (
It is already known to produce polysaccharides (hereinafter referred to as product polysaccharides).

The product polysaccharides thus obtained are water-soluble and stable compounds, and are therefore widely used as thickeners, detergents, printing pastes, sizing agents, and the like. Since the raw material polysaccharide is solid, in order to react it with alkylene oxide, a method is adopted in which the raw material polysaccharide is suspended or dissolved in a solvent and the reaction is carried out in a suspended or solution state. It was done. Water and organic solvents were used as solvents for this purpose. Whichever method is used, since the reaction is carried out by suspending or dissolving the raw material polysaccharide in a solvent, the solvent should be at least the same weight as the raw material polysaccharide, usually 2
It was necessary to use more than double the amount. When water is used as a solvent, the amount of solvent is even larger, at least 5
Double amount of water was used. The use of water as a solvent appears to be very advantageous since, compared to organic solvents, water poses no fire hazard and has no negative impact on the working environment.

However, when water is used as a solvent, the resulting product polysaccharide is dissolved in water and the viscosity of the reaction system increases, making uniform stirring difficult. Even larger amounts of water must be used to facilitate this. If a large amount of water is used, a large reactor is required, side reactions are likely to occur, and the reaction efficiency is reduced by 20 to 30%. In addition, it takes time and effort to separate the resulting product polysaccharide from water, making it impossible to economically obtain the hydroxyalkylated polysaccharide. On the other hand, methods using organic solvents have the advantage of being easy to stir because the product polysaccharides do not dissolve in the organic solvents, but they require large amounts of equipment and require large amounts of solvent. There was a drawback of doing so.

It was also necessary to pay attention to the work environment and fire prevention. Furthermore, side reactions are likely to occur, and although the reaction efficiency is better than when water is used,
It remained at 0%, and could not be said to be an advantageous method. The inventor attempted to improve the drawbacks of the conventional method as described above.

We then investigated whether the above-mentioned reaction could proceed in the absence of a substantial solvent. In the case of granular polysaccharides such as starch,
As shown in Japanese Patent No. 39386, by using an organic amine as a catalyst, alkylene oxide can be reacted with the organic amine in powder form. However, when a non-granular polysaccharide was used as a raw material, it was found that even if an organic amine was added as a catalyst to the powdered raw material polysaccharide, the alkylene oxide did not react with it.
The inventor then dissolved the caustic soda in a small amount of methanol and added a small amount of this solution to the powdered non-granular polysaccharide to introduce the alkylene oxide. As a result, it has been found that the non-granular polysaccharide reacts with alkylene oxide in a slightly moist powder form to obtain the desired hydroxyalkylated polysaccharide.
After further experimentation, I learned that in this case, you can also add a small amount of water. In that case, in order to proceed with the reaction in a slightly moist powder state, the amount of caustic soda should be 2 to 20 parts by weight, the organic solvent should be 2 to 30 parts by weight, and the water should be added to 100 parts by weight of the raw material polysaccharide. Also, 2
I learned that it is necessary to keep the amount below 0 parts by weight. This invention was completed based on such knowledge. This invention involves adding 2 to 30 parts by weight of an organic solvent, 0 to 20 parts by weight of water, and 2 to 20 parts by weight of caustic alkali to 100 parts by weight of a non-granular polysaccharide; The present invention relates to a method for producing a hydroxyalkylated polysaccharide, which comprises adding an alkylene oxide and reacting the polysaccharide with the alkylene oxide in a slightly moist state.

In this invention method, a non-granular polysaccharide is used as a raw material.

This raw material polysaccharide consists of pregelatinized starch, oral cast bean gum,
Guar gum, tamarind gum cellulose, etc. However, corn starch and potato starch. Starches such as wheat starch have granules, so they are not included in non-granule polysaccharides. It is desirable that the raw material polysaccharide is made into a fine powder. In this invention method, a sealable container equipped with a stirring mechanism is used as the reaction container.

After the raw material polysaccharide is placed in this container, the pressure inside the container is reduced to eliminate some of the air within the container. Decompression is 100m
About mHg is sufficient. Further, it is desirable that this container be of a jacket type so that it can be heated and cooled freely from the outside.

Organic solvents are used in the method of this invention.

The amount of organic solvent used is 2 to 30 parts by weight per 100 parts by weight of raw material polysaccharide. Among these, 3 to 20 parts by weight is preferred, and 4 to 12 parts by weight is most preferred. Suitable organic solvents include those compatible with water, particularly lower alcohols such as methanol, ethanol, and isopropanol. In addition, butanol, acetone, methyl ethyl ketone. Tetrahydrofuran, dioxane, etc. can be used.
Suitable organic solvents are those that have the effect of moistening the raw material polysaccharide and slightly dissolving the caustic alkali. The reason why the amount of organic solvent is limited to the above range is that if it is less than 2 parts by weight, alkaline adducts will not be uniformly formed on the surface of the raw material polysaccharide, whereas if it is more than 30 parts by weight, the raw material polysaccharide will be locally This is because it becomes gelatinized or becomes a slurry, leaving it in a slightly damp state. This invention method uses caustic alkali.

Caustic alkali acts as a catalyst when reacting raw material polysaccharide with alkylene oxide. As the caustic alkali, caustic soda and caustic potash are suitable. The caustic alkali is used in an amount of 2 to 20 parts by weight per 100 parts by weight of raw material polysaccharide, preferably 3 to 10 parts by weight, and particularly preferably 4 to 6 parts by weight. The reason why the caustic alkali is limited to the above range is 2.
If the amount is less than 20 parts by weight, the amount of caustic alkali on the surface of the raw material polysaccharide will be insufficient and the reaction will not proceed uniformly.On the other hand, if it is more than 20 parts by weight, the product will locally gelatinize, resulting in poor performance. This is because the product cannot be obtained. In the method of this invention, water is also used, but it is necessary to limit the amount of water to the minimum amount necessary for producing a caustic alkaline adduct on the surface of the raw material polysaccharide.

Therefore, water is used in an amount of 0 to 20 parts by weight based on 100 parts by weight of raw material polysaccharide. Among these, the preferred range is O to 10 parts by weight, and the most preferred range is O to 6 parts by weight. In the first place, since at least a few percent of water is contained in the polysaccharide raw material, there is no need to add water. Therefore, water may not be added. The reason why the amount of water is 20 parts by weight or less is because if the amount of water exceeds this amount, the polysaccharide will locally gelatinize, which will cause side reactions, making it impossible for the reaction to proceed smoothly in a slightly moist state. It is. There is no particular limitation on the order in which the caustic alkali, the organic solvent, and, if necessary, water are added to the raw material polysaccharide.

However, a preferred method is to dissolve caustic alkali in advance in a mixture of an organic solvent and water, and then add this solution to the raw polysaccharide. In addition, a preferred method is to first add an organic solvent mixed with water if necessary to the raw material polysaccharide, and then add solid caustic alkali to this. In the method of this invention, a caustic alkali, an organic solvent, and, if necessary, water are added to the raw material polysaccharide, and then the mixture is thoroughly stirred.

If the caustic alkali is added as a solid, the caustic alkali becomes fine powder due to friction with the raw material polysaccharide during stirring, and is dissolved in the organic solvent or a mixture of water and organic solvent to form a solution. becomes. The solution thus produced, or the solution added in the form of a solution from the beginning, adheres to the surface of the raw material polysaccharide, forming a uniform alkali adduct. This alkali adduct acts as a catalyst. At this time, since the total amount of the organic solvent and water added is only 3 to 50 parts by weight based on 100 parts by weight of the raw material polysaccharide, the raw material polysaccharide is only slightly moistened. The state is, so to speak, a powder state, not a slurry state. Therefore, stirring is easy. In this invention method, alkylene oxide is added to the raw material polysaccharide while stirring it.

Examples of alkylene oxide include ethylene oxide,
Propylene oxide, butylene oxide, etc. can be used. The amount added varies depending on the degree of hydroxyalkyl group to be introduced, but is usually in the range of 2 to 70 parts by weight per 100 parts by weight of the raw material polysaccharide. In the method of this invention, the raw material polysaccharide is maintained at a temperature of 40 to 1200C after alkylene oxide is added.

If necessary for this purpose, the reaction vessel is heated externally.
The reason for maintaining this temperature is that if it is below 40°C, the reaction rate will be slow and it will take a long time to complete, which is disadvantageous.On the other hand, if it is above 120°C, the raw material polysaccharide will locally become sticky. This is because the reaction cannot proceed in the powder state. When raw material polysaccharide starts to react with alkylene oxide, the reaction is exothermic and generates heat, which means that it must be cooled from the outside. In the method of this invention, the completion of the reaction is known by the decrease in the pressure within the system.

In other words, the reaction takes place at a temperature above the boiling point of the alkylene oxide, so the pressure in the system is high until the hydroxyalkylation reaction begins, and as the reaction progresses, the alkylene oxide is consumed, so the pressure in the system decreases. . Therefore, when the pressure in the system decreases and becomes constant, it can be considered that the reaction has ended. After the reaction is completed, an acid such as acetic acid is added to the polysaccharide produced to neutralize the caustic alkali.

Thereafter, the product is dried under reduced pressure to remove the added organic solvent or water. According to the method of this invention, a small amount of solvent is used, and even when combined with water, the amount is less than 50 parts by weight per 100 parts by weight of the raw material polysaccharide, and most of the solvent is an organic solvent, so the raw material Keeping the polysaccharide slightly moist,
Alkyl oxidation can be carried out. the result,
According to the method of this invention, a large-capacity reactor is not required, stirring is easy, side reactions are suppressed, and the reaction can be carried out efficiently.Furthermore, the solvent can be removed after the reaction is completed. This provides a number of advantages, including ease of use. Moreover, the products obtained by the method of this invention have a quality that is as good as, if not better than, conventional products, and can be used for various purposes in the same way as conventional products. Therefore, the method of this invention has great practical value. Next, the details of the method of this invention will be explained with reference to Examples.

Example 1 Pregelatinized corn starch (moisture content approximately 8%) in a sealable container.
) and seal it, the pressure inside the container is 100mmHg.
The pressure was reduced until

Next, open the valve and add 809 parts of caustic soda and 8 parts of water.
A mixed solution of 09 and methanol 1609 was injected and stirred for 1 hour. Thereafter, the valve was opened, and propylene oxide 2009 was injected therein, the temperature was raised to 70°C, and the mixture was stirred for 3 hours. During this time, the temperature in the reaction system was kept at 80-90°C.
It was kept at ℃. Thereafter, it was cooled, neutralized with acetic acid, and dried under reduced pressure for 1 hour to obtain a product. The product thus obtained had a degree of substitution by hydroxypropyl groups of 0.37, and was good for making. In addition, the reaction efficiency was 58%, which was found to be good. Example 2 Place locust bean gum (moisture content approx. 9%) in a V-type blender.
) After adding 1000g, 100g of caustic soda in solid state
9 and ethanol 1009 were added and mixed for 30 minutes.

Thereafter, this mixture was transferred to a sealable container and sealed, and then the pressure inside the container was reduced to 100 mHg. Next, the valve was opened and propylene oxide 1009 was injected therein, and then the temperature was raised to 90° C. and stirred for 1.5 hours to cause a reaction. During this time, the temperature in the system was set to 90-10
It was maintained at 0°C. After the reaction was completed, it was neutralized with acetic acid and dried under reduced pressure for 30 minutes to obtain a product polysaccharide. The degree of substitution by hydroxypropyl groups in the product polysaccharide was 0.19, and the product was good. Also, the reaction efficiency is 62
% was found to be good. Example 3 1000 guar gum (moisture content approximately 9%) in a sealable container
9 and seal it, reduce the pressure inside the container to 100 mmHg, then open the valve and add caustic soda 6.
A solution consisting of 0.09 and methanol 2509 was injected and stirred for 1 hour.

Then, open the valve and use propylene oxide 809.
was injected, and the temperature was subsequently raised to 90° C., and stirring was continued for 1.5 hours to carry out the reaction. During that time, the temperature in the system was set to 90
The temperature was maintained at ~100°C. After the reaction is complete, neutralize with acetic acid and
A product was obtained by drying under reduced pressure for 0 minutes. Product substitution degree is 0.1
5, the product is of good quality, and the reaction efficiency is 60%.
It was recognized as being in good condition. Example 4 Cellulose powder (moisture content about 6%) 10 in a V-type blender
After adding 009, a mixed solution of 80 y of water and 2009 methanol and solid caustic soda 1509 were added separately and stirred for 1 hour.

Thereafter, this mixture was transferred to a sealable container and sealed, and the pressure inside the container was reduced to 100 mmHg.
Next, after opening the valve and injecting propylene oxide 4509, the temperature was raised to 60°C and stirring was continued for 4 hours, during which time the temperature in the system was maintained at 60 to 80°C to carry out the reaction. After the reaction was completed, the mixture was neutralized with acetic acid and dried under reduced pressure for 1 hour to obtain a product. The degree of substitution of the product is 0.68, and the reaction efficiency is 5
1%, and it was recognized that both the product and the efficiency were good. Comparative Example 1 This comparative example was conducted in the same manner as Example 3, except that in this example, the amount of methanol was increased, the reaction temperature was lowered, and the reaction was carried out for a long time.

The reaction temperature was lowered because if the reaction was carried out at a high temperature as in Example 3, there was a risk that a large amount of methanol would react with propylene oxide, reducing the reaction efficiency of the product. Specifically, after reducing the pressure in a container containing guar gum 10009, caustic soda 609 and methanol 1
After injecting a solution consisting of
The reaction was allowed to take place for a period of time.

After the reaction was completed, the mixture was neutralized with acetic acid, the solvent was filtered off, and the mixture was dried under reduced pressure for 3 hours to obtain a product. The degree of substitution of this product is 0.0
8, and the reaction efficiency was 34%, which was inferior to Example 3. Moreover, it was not advantageous because it required separation to produce a product and it took time to dry under reduced pressure. Comparative Example 2 This comparative example was similar to Example 3, but was carried out according to conventional methods without using an organic solvent and instead using a large amount of water.

Specifically, 10 kg of water and caustic soda 609 were added to a container and dissolved uniformly, and then, while stirring, 1000 g of guar gum used in Example 3 was added little by little and stirred until a homogeneous solution was obtained.

Claims (1)

[Claims] 1 For 100 parts by weight of non-granular polysaccharide, 2
30 to 30 parts by weight of an organic solvent, 0 to 20 parts by weight of water, and 2 to 20 parts by weight of caustic alkali are added, and then alkylene oxide is added to the above polysaccharide in a slightly moist state. A method for producing a hydroxyalkylated polysaccharide, which comprises reacting with an oxide.