JPS58108202A - Preparation of hydroxyalkyl ether of galactomannan - Google Patents

Abstract

PURPOSE:To obtain inexpensively the titled compound capable of keeping an aqueous solution of galactomannan at high viscosity free from reduction in viscosity caused by decomposition, by reacting galactomannan with an alkylene oxide in a galactomannan suspension to which a nitrogen-containing basic substance is added. CONSTITUTION:In a suspension obtained by adding (D) a nitrogen-containing basic substance (e.g., ammonia, etc.) to a mixture of (A) a hydrophilic organic solvent (preferably acetone, etc.), (B) water, and (C) galactomannan, the component C is reacted with (E) an alkylene oxide (e.g., ethylene oxide, etc.) in an amount to give preferably 0.1-2mol based on unit anhydro saccharide of the component C usually at 30-100 deg.C, and the reaction product is dried, to give the desired compound. A weight ratio of the component A to the component B is preferably (30:70)-(95:5). EFFECT:When it is dissolved in water, powdery particles will not cause solid granulation and a high-quality compound with low ash is obtained.

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 having mannose as a structural unit and galactose units as side chains, and is mainly contained in large amounts in the seeds of leguminous plants in nature. In particular, guar gum made from guar beans and locust bean gum made from locust beans are representative vegetable gums containing galactomannan as a main component. These plant gums are plant mucilage substances, 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 an aqueous solution, they tend to cause agglomeration of powder particles called "mamako", and aqueous solutions of galactomannans are susceptible to attack by bacteria and deteriorate over time, causing a decrease in viscosity. It has a drawback.

The present inventors have arrived at the present invention as a result of their studies aimed at developing a modified galactomannan that overcomes these drawbacks while maintaining the extremely high viscosity that is characteristic of galactomannan aqueous solutions. .

The hydroxyalkyl ether of galactomannan obtained by the present invention does not impair the inherent nonionic properties of galactomannan (it reduces the viscosity change over time of an aqueous solution caused by bacteria, and the viscosity of the aqueous solution is stable at a pH of 12 or less). The hydroxyalkyl ether of galactomannan of the present invention can maintain the viscosity of an aqueous solution at υ8°C even in the presence of high concentrations of various salts containing polyvalent ions. It is mainly used in industrial fields such as paper manufacturing, cosmetics, paints, civil engineering, architecture, petroleum, and explosives.

U.S. Patent No. 2496 is a method for producing hydroxyalkyl ethers of galactomannan that has been developed so far.
There is a method disclosed in No. 670, in which galactomannan is reacted with glycerin monohalohydrin in an alkaline environment using water as a medium, and the galactomannan is alkalized and then reacted with glycerin monohalohydrin. It is something that makes you

According to this method, firstly, the hydroxyalkyl etherification reaction of galactomannan proceeds by a desalting reaction, which inevitably leaves a large amount of salt in the product. ``4-This fact poses a serious drawback from the user's point of view of the presence of excessive ash content in the product.

Second, since the reaction takes place in water as a medium, galactomannan and its reaction products must be dissolved in water and the reaction must proceed in an extremely highly viscous state.
This is not a preferred method because it causes non-uniform reaction, non-uniform neutralization, and difficulties in stirring, transportation, drying, etc. during the manufacturing process. Furthermore, thirdly, we compared the method using only water as a reaction medium using a reaction vessel of the same volume with the method of the present invention in which galactomannan is suspended in a mixture of a hydrophilic organic solvent and water. In this case, the amount of galactomannan that can be charged in the second reaction is larger in the present invention.

Furthermore, the existing method disclosed in U.S. Pat. The hydroxyalkyl etherification reaction is carried out with galactomannan suspended, and as the reaction progresses, the hydroxyalkyl ether of galactomannan that is produced swells or dissolves in the suspension medium, resulting in extremely poor mobility. Since it becomes a cloudy liquid, it causes inconvenience when performing neutralization, purification, etc. after the reaction is completed. In other words, when neutralizing the solution after the completion of the reaction, an acid is added, but when a dilute acid is used as the acid, the ratio of the hydrophilic solvent in the suspending medium further decreases, resulting in the formation of The hydroxyalkyl ether of galactomannan further swells or dissolves in water, forming a suspension with poor mobility in the medium, making it difficult to stir the suspension, which in turn induces non-uniform neutralization, resulting in a good neutralization. This leads to the result of disturbing harmony. Furthermore, since the steps after neutralization proceed in a highly viscous state containing the hydroxyalkyl ether of galactomannan swollen or dissolved by water, the steps become complicated and individual unit operations become extremely difficult. invite. On the other hand, in order to avoid the above-mentioned disadvantages, there is a method in which the neutralization operation is performed using a concentrated acid, but such a method involves adding a concentrated acid to a suspension of hydroxyalkyl ether of galactomannan, which has extremely poor mobility. Therefore, it is difficult to neutralize completely uniformly, and as a result of locally adding excess acid, the formed hydroxyalkyl ether is exposed to a locally strong acidic atmosphere, resulting in the formed hydroxyalkyl ether. Galactomannan easily passes through the neutralization process because it causes local acid hydrolysis, resulting in deterioration of the product, such as not being able to achieve the aqueous solution viscosity expected of hydroxyalkyl etherified galactomannan. It is difficult to do so.

Furthermore, the solid-liquid separation process requires a great deal of effort. That is, when performing solid-liquid separation of a suspended hydroxyalkyl ether of galactomannan that swells or dissolves in a suspending medium and has extremely poor mobility, solid-liquid separation is completely impossible if it is in a dissolved state; If it is in a swollen state, the filtration operation will be extremely difficult.

That is, the hydroxyalkyl ether of galactomannan in a swollen state adheres to each other and blocks the filter medium when external forces such as pressurization or vacuum are applied. Further, even by centrifugation, good separation is not achieved, and instead the particles in the swollen state adhere to each other to form a large gel-like mass, making it impossible to overcome the disadvantages of the liquid-containing swollen state.

As discussed above, the suspension method that has been developed in the past is more preferable than the method using water as a medium11, but the process from the completion of the hydroxyalkylation reaction of galactomannan to the purification and separation of the product is The current situation was that it was difficult to pass it easily. In view of the above circumstances, the present inventors have conducted extensive research to obtain a hydroxyalkyl ether of galactomannan that is inexpensive and of excellent quality, and as a result has arrived at the present invention.

The gist of the present invention is to react a suspension obtained by adding a nitrogen-containing basic substance to a mixture of a hydrophilic organic solvent, water, and galactomannan with an alkylene oxide, and then drying the reaction product. An object of the present invention is to provide a method for producing a hydroxyalkyl ether of galactomannan, which is characterized by the following.

The most significant feature of the present invention is that it can significantly simplify the post-processing process after the hydroxyalkyl etherification of galactomannan, which was considered to be an indispensable step in the retrieval technique. Conventionally, the above-mentioned post-treatment is one of the methods for improving product quality by neutralizing a strong alkali necessary for the hydroxyalkyl etherification reaction of galactomannan and removing salts, which are the main component of the ash produced by this neutralization reaction. This has the advantage that the content can be reduced.

Conventionally, inorganic acids and organic acids have been used to neutralize such alkaline materials, but in particular, when an inorganic acid is used, the ash content in the resulting product increases. Organic acids that are less likely to cause 6 formation are often used. However, it is difficult to achieve sufficient neutralization by neutralizing a strong alkaline substance with a stoichiometric amount of an organic acid, and the resulting product is alkaline.

In view of the current situation, the present inventors have sufficient ability to proceed with the reaction with weak alkalinity as a basic substance used in the hydroxyalkalization of galactomannan. We have discovered a method that can omit the neutralization step of the system. Furthermore, since the hydroxyalkyl etherification of galactomannan using such a weakly alkaline substance can proceed extremely smoothly, it is possible to reduce the amount of the basic substance used in the hydroxyalkyl etherification process, thereby reducing the ash in the resulting product. This allows the amount to be reduced.

The form of the galactomannan used in carrying out the present invention may be in the so-called split state obtained by coarsely pulverizing beans, or in the form of a powder obtained by further pulverizing the galactomannan. Furthermore, powdered galactomannan purified with ether, alcohol, benzene, etc. may also be used. Also pyrolysis.

Galactomannan whose molecular weight has been lowered by oxidative decomposition, enzymatic decomposition, acid hydrolysis, etc. can also be used. In addition, the hydrophilic organic solvent used as a reaction medium refers to an organic solvent that contains at least 30% water by weight and can be mixed with water without separating from it. It is preferable that it is difficult to react with both the substance and alkylene oxide. Specific examples of these hydrophilic organic solvents include alcohols such as methanol, ethanol, propatool and butanol, ketones such as acetone and methyl ethyl ketone, and mixtures thereof, with 2-propatool being preferred.

These include tertiary butanol, acetone, and methyl ethyl ketone. The ratio of the hydrophilic organic solvent to water is preferably 30 j 70 to 95:5 by weight.

When the amount of water decreases below the composition ratio of hydrophilic organic solvent and water of 95 = 5, the reaction rate of hydroxyalkylation of galactomannan decreases markedly, and the reaction hardly progresses, and even after the reaction is completed. This is not preferable since the amount of alkylene oxide remaining in the reaction solution becomes extremely large. As the ratio of water to the mixture of hydrophilic organic solvent and water increases, the reaction rate increases and it becomes possible to obtain favorable reaction conditions. In addition, the amount of alkylene oxide remaining in the reaction solution after the reaction is completed is preferably reduced, and furthermore, the effective utilization rate of alkylene oxide is increased, and a high rate of 80% can be achieved. However, when the amount of water increases beyond the composition ratio of hydrophilic organic solvent and water < 30 nia 0, galactomannan and droxyalkyl ether produced during the reaction become stable in suspension in the suspending medium. It can exist in this state, but it will dissolve and thicken.

According to the method of the present invention, since a hydrophilic organic solvent water bath solution having the above-mentioned composition is used, it may be possible to increase the concentration of galactomannan charged prior to the start of the reaction. The weight concentration of galactomannan in the hydrophilic organic solvent aqueous solution is hereinafter referred to as slurry concentration. In general, according to conventionally disclosed methods, when the slurry concentration is increased, the viscosity of the system after the completion of the hydroxypropylation reaction of galactomannan increases significantly, making it impossible to perform neutralization and solid-liquid separation satisfactorily.

Examples of nitrogen-containing basic substances used in carrying out the present invention include ammonia, organic amines, and the above-mentioned quaternary ammonium compounds. When the hydroxyalkyl etherification of galactomannan is carried out using the nitrogen-containing basic substance as a catalyst, the amount of catalyst used can be reduced, and the resulting system after the reaction is Since it does not exhibit strong °C or alkalinity, it is possible to completely eliminate the neutralization step of the reaction completion system, which is unnecessary in the conventional method. Deterioration in handling properties due to increased viscosity of the entire system has been a major problem, but in the present invention, by using the above-mentioned catalyst, the process of neutralizing the system after the completion of the reaction can be omitted. Clean and then wash 1
There is no need to perform 1 separation or the like. Since the slurry concentration of the system after the completion of the hydroxyalkyl etherification reaction of galactomannan according to the present invention is significantly higher than that in the conventional method, the hydroxyalkyl etherified galactomannan is not separated from the reaction mixture and the next drying process is carried out immediately. The process also has the great advantage of being used, and in this drying process, nitrogen-containing basic substances are volatilized and recovered and reused.

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 monooxide.

Examples include glycide. In the reaction, these substances can be added to the reaction system in either gaseous or liquid form, and even if the entire amount is charged before the reaction, it is possible to add them to the reaction system sequentially. The amount of alkylene oxide used can be arbitrarily changed depending on the degree of modification of galactomannan, but is preferably from 0.01 mol to 6 mol per anhydrosaccharide unit of galactomannan.
The amount is between 0.1 mol and 2 mol, more preferably between 0.1 mol and 2 mol.

The reaction is usually carried out between 30°C and 100°C, and the reaction time is sufficient to achieve a predetermined degree of modification (MS). Preferably it is 2 hours to 24 hours. The form of the reaction vessel may be any one such as a normal pressure reflux type vessel, a pressurized stirring vessel, a pressurized Nigu, a pressurized Brengu, etc.

Various methods can be used to dry the suspension dispersion obtained by reacting an alkylene oxide with a suspension obtained by adding a basic substance to a mixture of a hydrophilic organic solvent, water, and galactomannan according to the present invention. First to be adopted. For example, methods such as casting a suspension dispersion to produce a dry film and then grinding; drying with a drum dryer;
A method of extruding a cloudy suspension dispersion through a die as a thin layer and drying it is employed. Further, drying may be performed in air or in an inert gas such as nitrogen. Further, drying may be performed under normal pressure or under reduced pressure.

A more detailed explanation will be given below in Examples.

Example 1 In a 4-ton flask with an internal volume of 1 ton equipped with a stern, a condenser, a dropping funnel, and a thermometer, 200% of 2-probanol, 40% of water, and 200f of guar gum powder with a moisture content of 12% were charged and stirred to homogenize. Make a suspension dispersion. Thereafter, an aqueous sodium hydroxide solution containing 20 g of triethylbenzylammonium chloride dissolved in 50 bottles of water was gradually added dropwise through a dropping funnel. After stirring for 1 hour,
Propylene oxide (f) was added dropwise from the dropping funnel, and the entire flask was heated to 70°C in a water bath, and the reaction was continued for 3 hours. Thereafter, the inside of the flask was cooled to below 35°C, the contents were taken out, cast onto a glass plate, and dried in a vacuum dryer at 70°C for one day and night. Thereafter, it was crushed to obtain a product. The product yield was 2701 with a moisture content of 22%. The ash content of this product was 3.2.

Example 2 In a pressurized kneader having an internal volume of 1 ton, 500 f of guar gum powder with a water content of 12%, 450-2 paropanol, and 100-1 water were added and kneaded. Thereafter, 100 g of an aqueous solution of 25% trimethylbenzylammonium hydroxide was added gradually to the mixture and kneaded. After that, close the container, replace it with nitrogen, and then add ethylene oxide 7.
22 was gradually added and the reaction was continued at 60°C for 8 hours. After the reaction was completed, the reactor was brought to room temperature and replaced with nitrogen again. The contents were taken out and formed into a thin plate. After that, it was dried in a vacuum dryer for 1 day and 7 hours.
It was dried at 0°C. Thereafter, the thin plate was crushed to obtain guar gum hydroxyethyl ether. The ash content of the product thus obtained was 2.0%.

Implementation mission 1] 3 Locust bean gum 100f and 150 with a moisture content of 10
-2 glopanol and 30m7! The mixture was put into the same reactor as in Example 1 together with water and stirred to produce a uniform suspension and dispersion. Thereafter, an aqueous solution of trichloride 5f dissolved in 50-g water was gradually added.

After stirring at room temperature for 1 hour, propylene oxide 301 was added, the entire flask was heated to 60°C in a water bath, and the reaction was continued for 10 hours. After that, the inside of the flask was
It was cooled to below ℃ and the contents were taken out. The contents were formed into a thin plate, air-dried for one day and night, and then dried in a ventilation dryer at 70°C for 3 hours, and then crushed to obtain hydroxypropyl ether of locust pea gum. The ash content of the product thus obtained was 4.5%.

Example 4 Guar gum powder 5002 with a water content of 12%, 400 mm of 2-proper tool, and 100 mm of water were added to a pressure kneader having an internal volume of 1 ton and kneaded together. 9chi diethylamine 25
Gradually add f to the kneader together with 100 f of water and knead. Thereafter, the container was closed and replaced with nitrogen, and then ethylene oxide 721 was gradually added and the reaction was continued at 80° C. for 4 hours.

After the reaction was completed, the reactor was brought to room temperature and replaced with nitrogen again, and the contents were taken out and formed into a thin plate, which was air-dried for one day and night, and then dried in a ventilation dryer at 70°C for 6 hours. Thereafter, the thin plate was crushed to obtain hydroxypropyl ether of guar gum. The ash content of the product thus obtained was 2.5%.

Patent applicant Mitsubishi Acetate Co., Ltd. Mitsubishi Rayon Co., Ltd. Agent Patent attorney 1) Satoshi Muratake

Claims (1)

[Claims] Galacto, which is characterized by reacting alkylene and oxide in suspension I obtained by adding a nitrogen-containing basic substance to a mixture of a hydrophilic organic solvent, water, and galactomannan, and then drying the reaction product. Method for producing hydroxyalkyl ether of mannan.