JPH0113484B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a hydroxyalkyl ether of galactomannan.

Galactomannan is a neutral polysaccharide composed of a main chain consisting of mannose as a constituent unit and galactose units as side chains.In nature, it is mainly contained in the seeds of leguminous plants, and in particular it is produced from guar beans. Typical vegetable gums containing galactomannan as a main ingredient include guar gum made from guar gum, and locust bean gum made from locust beans.

These plant gums containing galactomannan as a main component are plant mucilages, and because they exhibit extremely high viscosity when dissolved in water, they are widely used in the food and industrial fields. However, when these galactomannans are made into aqueous solutions, they tend to cause agglomeration of powder particles called "mamako", and aqueous solutions of galactomannans are susceptible to attack by bacteria and rot over time, causing a decrease in viscosity. It has the disadvantage of The present inventors have arrived at the present invention as a result of their studies aimed at developing an improved modified galactomannan that can overcome these drawbacks while maintaining the extremely high viscosity that is characteristic of galactomannan aqueous solutions.

The highly modified hydroxyalkyl ether of galactomannan obtained by the present invention has a stable aqueous solution viscosity with a pH of 12 or less without impairing the nonionic properties inherent in galactomannan, and It also has the property of being able to maintain high aqueous solution viscosity even in the presence of high concentrations of various salts containing multivalent ions. Due to these properties, the hydroxyalkyl ether of galactomannan obtained by the present invention can be usefully used mainly in industrial fields such as paper manufacturing, cosmetics, paints, civil engineering, architecture, petroleum, and explosives.

Conventional methods for producing hydroxyalkyl ethers of galactomannan include US Patent No. 2496670.
There is a method disclosed in No. This method is a method in which galactomannan is reacted with glycerin and monohalohydrin in an alkaline environment using water as a medium, and the galactomannan is alkalized and then reacted with glycerin monohalohydrin.

According to such a method, first, the reaction proceeds by desalting reaction, which inevitably leaves a large amount of salt in the product. This fact has a serious drawback from the user's point of view of the presence of excessive ash content in the product. Secondly, since the reaction uses water as a medium, galactomannan and the reaction product must be dissolved in water and the reaction must proceed in an extremely highly viscous state, resulting in non-uniformity of the reaction during the manufacturing process and neutralization. This is not a preferred method due to non-uniformity and difficulty in controlling processes such as stirring, transportation, and drying. Furthermore, thirdly, when using reaction vessels of the same volume, there is a method in which only water is used as the reaction medium, and a method of the present invention in which the reaction is carried out by suspending galactomannan in a mixture of a fresh aqueous organic solvent and water. When compared with the method of the present invention, the amount of galactomannan that can be charged in one reaction is larger in the method of the present invention. Additionally, the method disclosed in U.S. Patent No. 3,326,890 employs a suspension method, but in the method disclosed in that patent, the alkaline reagent used as a reaction catalyst is an organic amine and a quaternary organic ammonium hydroxide. .

According to the results of a supplementary test conducted by the present inventors on the method disclosed in the patent, the reaction rate between alkylene oxide and galactomannan is slow and galactomannan is The effective utilization rate of the reaction of alkylene oxide to mannan is low at less than 40%, and the MS (number of moles of alkylene oxide added per anhydrosaccharide unit), which is a measure of the degree of modification of the product, is also low.
0.1 or less, which is insufficient. This method also has disadvantages such as a large amount of unreacted etherification reagent remaining after the reaction is completed. Furthermore, the disclosed method for producing hydroxyalkyl ether of galactomannan has been accompanied by many difficulties in producing highly modified hydroxyalkyl ether of galactomannan.

Here, MS indicating the degree of modification of galactomannan is a numerical value indicating the number of moles of alkylene oxide added per anhydrosaccharide unit of galactomannan and indicating the degree of hydroxyalkylation of galactomannan. In particular, various methods known as methods for measuring MS such as hydroxyethyl cellulose and hydroxypropyl cellulose can be adopted as the method for measuring MS. For example, in Special Publication No. 42-10640,
Although a terminal methylation method using the Ziesel-Morgan method is disclosed, MS of the product obtained by the present invention is
In the case of hydroxyethyl ether of galactomannan, the measurement method is the MOLAR SUBSTITUTION measurement method shown in ASTMD-2364-75,
In the case of hydroxypropyl ether of galactomannan, it is shown in ASTMD-2363-72.
MOLAR calculated from Hydroxypropyl Content
Substitution was adopted. In some cases, MS values calculated from nuclear magnetic resonance spectra were also used.

Conventionally developed methods for producing hydroxyalkyl ethers of galactomannan, such as MS
No method has been found to produce modified galactomannan with a highly etherified reaction that has a value of 0.7 or higher, especially an MS value of 1 or higher, and galactomannan modified to have a MS value of 0.7 or higher has poor product characteristics. Despite its excellent properties, there is a strong desire for an effective manufacturing method.

Therefore, the present inventors conducted studies to obtain a highly modified galactomannan having an MS value of 0.7 or more, particularly 1 or more, and as a result completed the present invention.

The gist of the present invention is to add alkylene oxide to a suspension of alkaline hydroxyalkyl ether of galactomannan obtained by adding an alkali metal hydroxide to a mixture of a hydrophilic organic solvent, water, and hydroxyalkyl ether of galactomannan. An object of the present invention is to provide a method for producing a highly modified hydroxyalkyl ether of galactomannan, which is characterized by reacting the following.

The characteristics of the present invention are that a hydroxyalkyl ether of galactomannan is used as a starting material;
The reaction system is carried out in a state in which the hydroxyalkyl ether of galactomannan is suspended and dispersed in a mixed solvent of water and a hydrophilic organic solvent, and subsequent steps such as neutralization, washing, and purification can also be carried out in a suspended state. The hydroxyalkyl etherification reaction of galactomannan is extremely advanced compared to conventional methods because it is extremely easy to handle and because the alkali reagent used as the reaction catalyst is an alkali metal hydroxide. At the same time, since this reaction proceeds in a suspended state, the amount of salts produced as the reaction progresses is small, and the contamination of these salts into the hydroxyalkyl ether of galactomannan obtained can be reduced, making it a useful product with a low ash content. The point is that it can be made into a product.

The hydroxyalkyl ether of galactomannan used in carrying out the present invention can be a hydroxyalkyl ether of galactomannan that has an MS value of less than 0.7 and is produced using a conventionally developed technique, and can be in the form of a powder. In addition, a liquid-containing cake or slurry can also be used, but in particular, an alkali metal hydroxide is added to a suspension of a mixture of a hydrophilic organic solvent, water, and galactomannan, and then an alkylene It is preferable to use a hydroxyalkyl etherified product of galactomannan produced by addition reaction with oxide. The hydroxyalkyl ether of galactomannan with an MS value of less than 0.7 produced by such a method has uniform hydroxyalkyl etherification and is a powder with a uniform particle size, so it is suitable for carrying out the present invention. Uniform dispersion and suspension in the reaction medium can be carried out efficiently, and the subsequent hydroxyalkyl etherification reaction of the present invention can be carried out very smoothly. Hydrophilic organic solvents refer to organic solvents that contain at least 30% by weight of water and can be mixed with water without separating from it; such organic solvents include hydroxyalkyl ethers of galactomannan, alkali metal hydroxides, and alkylene It is preferable that any of the oxides is difficult to react with. Specific examples of typical hydrophilic organic solvents include alcohols such as methanol, ethanol, propanol and butanol, ketones such as acetone and methyl ethyl ketone, and mixtures thereof, but preferably 2-propanol, tertiary-butanol, Acetone, methyl ethyl ketone, etc. are used, and the amount used is preferably 30:70 to 95:5 in weight ratio of the hydrophilic organic solvent in the reaction system to which the alkali metal hydroxide is added to water. When the amount of water decreases below the composition ratio of hydrophilic organic solvent and water of 95:5, the reaction rate of hydroxyalkylation decreases markedly and the reaction hardly progresses, and the reaction and the reaction solution after the completion of the reaction decrease. The amount of alkylene oxide remaining therein becomes extremely large, which is undesirable. As the ratio of water to the mixture of hydrophilic organic solvent and water increases, the hydroxyalkyl etherification reaction rate increases and favorable reaction conditions can be achieved, and the amount of alkylene oxide remaining in the reaction solution increases. The effective utilization rate of alkylene oxide also increases, and a high rate of 80% can be achieved, but when the composition ratio of hydrophilic organic solvent and water increases from 30:70 to The hydroxyalkyl ether of galactomannan used as a raw material could not be stably dispersed in the reaction medium in a suspended state, and the entire system exhibited thickening properties, making it difficult to carry out the hydroxyalkyl etherification reaction of the present invention efficiently and uniformly. cause difficulties. Since this tendency becomes more pronounced as the hydroxyalkyl etherification of galactomannan progresses, it is necessary that the ratio of hydrophilic organic solvent to water be 30:70 or more.

Furthermore, when carrying out the present invention, the hydroxyalkyl ether of galactomannan with an MS value of less than 0.7 is
As the MS value is 0.7 or more, especially 1.0 or more, as the degree of modification progresses, it becomes easier to swell in an aqueous solution of a hydrophilic organic solvent, and the hydroxyalkyl ether particles of galactomannan in the slurry aggregate, causing a hydroxyalkyl etherification reaction and This results in a decrease in the ability of the obtained product to pass through processes such as filtration.

Furthermore, highly modified hydroxyalkyl etherified galactomannan can be used in hydrophilic organic solvents30.
Even if the aqueous solution has a concentration of 1% or more, it will show dissolution viscosity, and if this happens, it may no longer be possible to continue the hydroxyalkyl etherification reaction in the slurry, making it easier to purify the reaction product. In some cases, it may be difficult to send the product to a post-processing step.

From the above-mentioned tendency, in order to disperse and suspend galactomannan well in the hydroxyalkyl ether reaction medium, an aqueous solution containing a hydrophilic organic solvent of 30% or more and 95% or less is preferable, especially an aqueous solution containing 40% or more and 95% or less. It is preferable that there be.

An alkali metal hydroxide is used as the alkaline reagent used in carrying out the present invention. When hydroxyalkylating a substance with an active hydroxyl group, it is preferable to proceed with the reaction in the presence of a basic catalyst, but the MS value is 0.7 or more, especially 1.0.
When performing the above-mentioned highly hydroxyalkyl etherification modification, an alkali metal hydroxide is particularly preferred as the alkaline reagent, and this reagent is used in an amount of 10% by weight or less, particularly 5% by weight, based on the hydroxyalkyl etherified product of galactomannan. It is possible to efficiently produce products with an MS value of 0.7 or more, particularly 1.0 or more, even with a small amount of use, and it is also possible to reduce the ash content in the resulting product.

The alkylene oxide used in carrying out the present invention is a lower alkylene oxide, such as ethylene oxide, propylene oxide, 1,2 butylene oxide, butadiene monoxide, glycide, etc., and either gaseous or liquid forms can be used. It is also possible to charge the entire amount to the reaction system before the reaction or to add it to the reaction system sequentially. The amount of alkylene oxide can be arbitrarily changed depending on the degree of modification of the hydroxyalkyl ether of galactomannan, but preferably per anhydrosaccharide unit of galactomannan.
The amount is between 0.01 mol and 6 mol, preferably between 0.1 mol and 2 mol. The reaction is usually carried out at a temperature of 30°C to 100°C, and the reaction time is preferably a time sufficient to achieve a predetermined degree of modification (MS), and is usually 2 hours to 24 hours. The form of the reaction vessel may be any one of a normal pressure reflux type vessel, a pressurized/stirred vessel, a pressurized kneader, a pressurized blender, and the like.

In addition, even if the hydroxyalkyl group reacted with the galactomannan used as a starting material in carrying out the present invention and the hydroxyalkyl group reacted with the hydroxyalkyl group reacted in the reaction for further modification are the same, they may be different from each other. If desired, it is possible according to the invention to produce mixed hydroxyalkyl derivatives having mutually different hydroxyalkyl groups.

The highly hydroxyalkyl etherified galactomannan obtained as described above is then neutralized and filtered, but the reaction system always maintains a suspended state of galactomannan in the system. These treatments can be performed extremely easily.

The present invention deals with the advanced hydroxyalkyl etherification reaction MS of hydroxyalkyl etherified galactomannan with a small MS value, which is uniformly dispersed in a mixture of water and a water-soluble organic solvent with a specific composition.
It reacts to substances with a value of 0.7 or more, especially 1.0 or more, but the reaction is extremely efficient and does not cause problems such as thickening of the system, making it extremely difficult to manufacture using conventional methods. was considered difficult
A major feature is that hydroxyalkyl etherified galactomannan with an MS value of 0.7 or more, particularly 1.0 or more, can be efficiently produced.

The present invention will be explained in more detail with reference to Examples below.

Example 1 110 ml of acetone, 90 ml of water, moisture content 12%, MS value 0.4, ash content in a 4-necked flask with an internal volume of 1 equipped with a stirrer, condenser, dropping funnel, and thermometer.
Add 100 g of 1.3% hydroxypropylated guar powder and stir to make a uniform suspension and dispersion. Then, gradually add 3 g of sodium hydroxide to 50 ml through the dropping funnel.
A solution of sodium hydroxide dissolved in water is added dropwise at room temperature. After stirring at room temperature for 1 hour, 29g of propylene oxide was added dropwise from the dropping funnel.
The entire flask was heated to 80°C in a hot water bath, and the reaction was continued for 7 hours. Cool the inside of the flask to below 35°C, and gradually neutralize by dropping 4.3 ml of glacial acetic acid from the dropping funnel while stirring. Then, the reaction product is filtered and reused.
After washing with 200 ml of 90% acetone aqueous solution, it was filtered again, and after further washing with 150 ml of acetone, the reaction product was taken out and dried in a vacuum dryer at 70°C overnight. Then grind it with a coffee mill.
Highly modified guar gum hydroxypropyl ether was obtained by passing the entire amount through 150 meshes. The resulting product has a moisture content of 20% and a yield of 131
It was hot at g. The MS value of the product is 1.1 and the ash content is 2.3.
It was %. The color of the product was white with a very slight yellowish tinge.

Example 2 Moisture content 12% in a pressurized autoclave with an internal volume of 1
150 g of guar gum hydroxypropyl ether powder having an MS value of 0.4, 250 ml of 2-propanol, and 30 ml of water are charged and stirred to form a suspension dispersion. then 5
An aqueous solution of g of potassium hydroxide dissolved in 80 ml of water is gradually added to the suspension dispersion. Afterwards, the inside of the autoclave was replaced with nitrogen while stirring, and after stirring for 1 hour, 25g of ethylene oxide was added and heated to 55℃ for 6 hours.
Allowed time to react. After the reaction is completed, the autoclave is cooled to room temperature, replaced with nitrogen again, and the product is taken out. The reaction product was then neutralized with a stoichiometric amount of glacial acetic acid, filtered, washed with 250 ml of 90% 2-propanol solution, filtered again, washed with 150 ml of 2-propanol, filtered and air-dried. Thereafter, pulverization was performed to obtain hydroxyethyl hydroxypropyl ether of guar gum. The resulting product has a moisture content of 20%
The yield was 178g. The ash content of the product was 2.1% and the MS of the product was 0.78.

Example 3 MS obtained by further hydroxypropylating hydroxypropylated guar gum with an MS value of 0.5 using the same method as in Example 1, using 150 ml of 2-propanol, 20 ml, and water in the same reactor as in Example 1. Value 1.5 ash
100g 1.5% hydroxypropylated guar gum powder
A suspension dispersion was prepared under stirring. Next 3
A sodium hydroxide solution prepared by dissolving 1 g of sodium hydroxide in 50 ml of water was gradually added dropwise from the dropping funnel and stirred for 1 hour. After that, the reaction system was heated to 70°C in a water bath.
Propylene oxide was added through the dropping funnel.
15g was added. Thereafter, 15 g of propylene oxide was added every 2 hours for a total of 6 times over 12 hours to continue the reaction. After that, after confirming that the reaction product has cooled to below 35℃, add 4.3ml of glacial acetic acid to 100ml of 2
- A solution dissolved in propanol was added dropwise from the dropping funnel to effect neutralization. Thereafter, it was filtered, washed twice with 200 ml of a 95% aqueous 2-propanol solution, filtered again, and washed twice with 150 ml of 2-propanol, and then the reaction product was taken out and dried in a vacuum dryer at 70 DEG C. overnight. Thereafter, it was ground to obtain highly modified guar gum hydroxypropyl ether. M.S.
The value was 2.3 and the ash content was 2.1%. Furthermore, this highly modified guar gum hydroxypropyl ether
The reaction was carried out again in the same manner using 100 g of the starting material. The result was a highly modified MS2.8 ash content of 2.4%. Hydroxypropyl ether of guar gum could be obtained.

Example 4 100 g of locust bean gum hydroxypropyl ether powder with moisture content 10% MS value 0.4 was charged into the same reaction vessel as in Example 1 with 150 ml of 2-propanol and 30 ml of water and stirred to form a uniform suspension dispersion. make. Thereafter, an aqueous sodium hydroxide solution prepared by dissolving 2 g of sodium hydroxide in 50 ml of water was gradually added using a dropping funnel. After stirring at room temperature for 1 hour, 30g of propylene oxide was added dropwise through a dropping funnel and the entire flask was heated to 55°C in a water bath.
Raise the temperature to 1 and continue the reaction for 10 hours. Thereafter, the inside of the flask was cooled to below 35℃, and while stirring, 4.3 ml of glacial acetic acid was gradually added dropwise through the dropping funnel to neutralize the reaction product.Then, the reaction product was filtered and washed with 200 ml of 88% 2-propanol aqueous solution, and then again. Filter and add 150ml
After washing with 2-propanol, the reaction product was taken out and dried in a vacuum dryer at 70°C all day and night. Thereafter, the mixture was ground in a coffee mill, and the entire amount was passed through 150 meshes to obtain a highly modified locust bean gum hydroxypropyl ether. The resulting product has a moisture content of 18% and a yield of 140
It was hot at g. The color of the product was white with a slight yellow tinge, the ash content of the product was 2.2%, and the MS value was 1.3.

Example 5 100 g of the product obtained in Example 1 was added to the starting material of Example 1 (hydroxypropylated guar powder, moisture content
The reaction was carried out in the same container as in Example 1 under the same reaction conditions using the starting material instead of 12% MS0.4 (ash content 1.3%). As a result, we were able to obtain a product with an MS of 1.8. Next, using 100 g of this product as a starting material, a reaction was carried out in the same container as in Example 1 under the same reaction conditions. As a result, we were able to obtain a product with an MS of 2.5. Furthermore, a reaction was carried out using 100 g of this product as a starting material in the same container and under the same reaction conditions as in Example 1. the result
Highly modified hydroxypropylated guar powder with MS of 3.1 could be obtained.

Claims (1)

[Claims] 1. Reacting an alkylene oxide in a suspension of an alkaline hydroxyalkyl ether of galactomannan in which an alkali metal hydroxide is added to a mixture of a hydrophilic organic solvent, water, and a hydroxyalkyl ether of galactomannan with an MS value of less than 0.7. A method for producing a hydroxyalkyl ether of galactomannan modified to have an MS value of 0.7 or more, characterized by: