JPS6355523B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for producing carboxymethyl cellulose ether alkali salt (hereinafter referred to as CMC). [Prior art] CMC is an anionic water-soluble product obtained by etherifying cellulosic raw materials such as linter pulp and wood pulp with alkali hydroxide and chloroacetic acid, and then performing post-processing such as refining and crushing. It is a high molecular compound. The industrial method for producing CMC is to prepare alkali cellulose and etherify it with chloroacetic acid as an etherification agent, but this involves a neutralization reaction of chloroacetic acid and a reaction between alkali chloroacetate and alkali cellulose. There is. At that time, the amount of heat generated during neutralization of chloroacetic acid was 16.9kcal/mol (actual value) and 13.6kcal/mol of acetic acid.
In the method of manufacturing CMC by adding chloroacetic acid to alkali cellulose, the temperature of the system increases due to the heat of neutralization, and if the temperature locally reaches the etherification temperature, the etherification agent Since the etherification reaction proceeds before uniform dispersion, resulting in non-uniform substitution, it is no exaggeration to say that the removal of the heat of neutralization influences the production of highly uniform CMC. Removal of this heat of neutralization becomes an industrially difficult problem when the reaction scale is large and the amount of solvent is at a low magnification. In addition, the solvent method has recently become mainstream because it has a wide range of production possibilities in terms of degree of substitution, viscosity, purity, etc., and there are fewer side reactions, and various patent applications have been filed regarding the production of CMC using this method. For example, the Special Publication Act 32-2496
Publication No. 32-7349, Publication No. 44-560,
Examples include Publication No. 53-29357 and Japanese Patent Application Laid-Open No. 58-45201. In Japanese Patent Publication No. 32-2496, sodium chloroacetate is used as an etherification agent, so
Although there is no need to remove the heat of neutralization, if sodium chloroacetate is used in crystalline (powder) form,
It is difficult to uniformly dissolve the etherifying agent, and furthermore, the rate of dissolution of the etherifying agent is slow in the case of a normal solvent composition, resulting in a problem that the mixing reaction time becomes long.
To solve this problem, sodium chloroacetate can be used as a solution, but there is no other inexpensive and suitable solvent other than water. Furthermore, when water is used, the water content in the reaction system increases, which reduces the effective utilization rate of the etherifying agent and reduces the transparency of the product, which is not preferable. In Japanese Patent Publication No. 32-7349, chloroacetic acid is used as an etherification agent, but since it is difficult to remove the heat of neutralization, the temperature in the reaction system becomes high, and etherification occurs at the same time as the neutralization reaction of chloroacetic acid. Since the reaction also progresses, the alkali cellulose is partially destroyed and becomes a non-uniform CMC, which is not preferable. In Japanese Patent Publication No. 44-560, after preparing high-quality alkali cellulose using a large excess of alkali, the large excess of alkali is neutralized with an acid before adding an etherification agent, and etherification is started. However, when using a solvent with a low magnification, there is a large amount of heat generated due to the neutralization of a large excess of alkali and chloroacetic acid, resulting in the destruction of alkali cellulose and changes in the water composition in the reaction system. Good CMC cannot be obtained. Japanese Patent Publication No. 53-29357 describes a method for arcelization and etherification by adding cellulose, a solvent at least 21 times the weight of cellulose, sodium chloroacetate or neutralized sodium chloroacetate, and sodium hydroxide. . In this case, since the sodium chloroacetate is completely dissolved, the heat of neutralization reaction can be removed relatively easily, but the amount of solvent used is extremely large, so the energy cost for industrial solvent reuse is high. Moreover, it is not preferable because the reaction vessel also needs to be relatively large. In JP-A No. 58-45201, all chloroacetic acid is neutralized in the reaction system, so it is difficult to remove the heat of neutralization, and since etherification is carried out in a system with little alkali, CMC partially becomes an acid form. It takes a long time to prepare the sodium salt. Also
If the sodium salt of CMC is incompletely prepared, the resulting aqueous solution will gel, which is undesirable. Japanese Patent Publication No. 40-3965 describes a method of directly cooling the inside of the system using adiabatic expansion of high-pressure gas, but since the gas used is air or nitrogen gas, the cooling effect is poor, and the attached This is not desirable because the device is large-scale, expensive, and complicated. In addition, in Japanese Patent Publication No. 59-52161, a mixed gas such as an inert gas such as nitrogen gas, water vapor, or organic solvent vapor in the system is forcedly circulated, and after liquefying a part of the gas components in a fin cooler etc., A method of directly cooling the system by recirculating the gas has been described, but the equipment is complicated and expensive, and since water vapor is present in the gas components, the cooling section must be kept at temperatures below 0°C. If this is done, the cooling effect will be significantly reduced due to freezing, and in extreme cases, the fins may become clogged, which is not preferable. [Problems to be Solved by the Invention] The present invention solves the above-mentioned problems in the production of CMC, and also makes it possible to easily obtain CMC with a uniform degree of substitution compared to conventional CMC. This was done in order to provide a manufacturing method with a high effective utilization rate of the curing agent. [Means for solving the problem] The present invention is used in the production of CMC obtained by etherifying alkali cellulose obtained by reacting cellulose and alkali hydroxide in a water-containing organic solvent with an etherification agent. The present invention relates to a method for producing a carboxymethylcellulose ether alkali salt, characterized in that a water-containing organic solvent solution in which 20 to 60 mol% of chloroacetic acid is dissolved as an alkali chloroacetic acid salt is used as an etherification agent. [Example] In the present invention, alkali cellulose is obtained by reacting cellulose with alkali hydroxide in a water-containing organic solvent. The cellulose used is one obtained by pulverizing pulp such as linter pulp or wood pulp, which is usually used in the production of CMC. Examples of the alkali hydroxide include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, and among these, sodium hydroxide is particularly preferred for economical reasons. As the water-containing organic solvent, those commonly used in the production of CMC can be used to alcelize and etherify cellulose. Specific examples include lower alcohols such as methanol, ethanol, propanol, 2-propanol, butyl alcohol, aromatic hydrocarbons such as benzene and toluene, ketones such as acetone and ethyl methyl ketone, and ethylene glycol dimethyl ether. Examples include a mixture of at least one organic solvent selected from ethers and water. Among these, lower alcohols containing three or more carbon atoms in the molecule, one type selected from aromatic hydrocarbons, and a mixture of methanol and/or ethanol with water are preferred. Further, the composition of the water-containing organic solvent is preferably such that the weight ratio of organic solvent/water is 70/30 to 90/10. If the ratio of organic solvent/water in the water-containing organic solvent is less than 70/30, the effective utilization rate of the etherification agent will be significantly reduced, and if it exceeds 90/10, sufficient alkali cellulose cannot be prepared, so the etherification reaction is interrupted. results in an uneven reaction. A solution of the alkali hydroxide dissolved in a water-containing organic solvent is added to cellulose with stirring, and
Alkali cellulose can be obtained by alcelization at 40°C for 20 to 240 minutes. In this case, it is preferable to add a water-containing organic solvent in an amount of 3.3 to 5.5 times the weight of the pulp and an alkali hydroxide in an amount of 32% or more by weight of the cellulose. CMC can be obtained by adding an etherifying agent to the alkali cellulose obtained as described above at 25 to 30°C, raising the temperature, and etherifying the cellulose. The etherification agent is a mixture of chloroacetic acid and alkali salt of chloroacetic acid in the water-containing organic solvent. In this case, it is more preferable to use methanol or ethanol as the water-containing organic solvent, which increases the solubility of the neutralized product of chloroacetic acid. The amount of chloroacetic acid used is 0.6 per mole of anhydroglucose in cellulose, depending on the desired degree of substitution.
~5.0 mol is used, preferably 0.7-2.5 mol. The alkali salt of chloroacetic acid can be obtained by neutralizing the chloroacetic acid with, for example, sodium hydroxide, potassium hydroxide, etc. Among these, sodium hydroxide is preferred for economical reasons. The etherification agent is also used for the chloroacetic acid used.
20 to 60 mol %, preferably 20 to 50 mol %, is neutralized with alkali hydroxide. This is because a certain amount of alkali is essential for the preparation of alkali cellulose, and when the amount of alkali is secured to obtain a suitable alkali cellulose when completely neutralized, the alkali becomes excessive in etherification, and conversely, it is not suitable. When setting the amount of alkali for etherification, the amount of alkali is insufficient to obtain good alkali cellulose. When the concentration of the alkali chloroacetic acid salt is less than 20 mol%, it is almost as unfavorable as when chloroacetic acid is used alone. This is due to the partial destruction of alkali cellulose due to the addition of chloroacetic acid.
It is thought that etherification progressed unevenly. Furthermore, if the concentration of the alkali salt of chloroacetate exceeds 60 mol%, crystals of sodium chloroacetate will precipitate, resulting in a slurry-like mixture, which will result in non-uniform mixing, which is unfavorable in terms of properties. The alkali salt of chloroacetic acid is more preferably a salt obtained by neutralizing chloroacetic acid with an alkali hydroxide in a solvent because it has extremely good solubility. Further, it is necessary to use an etherification agent in which the alkali salt of chloroacetic acid and chloroacetic acid do not precipitate at 30°C and are completely dissolved. The concentration of the etherification agent as chloroacetic acid is
A substance containing 40 to 70% by weight, preferably 50 to 70% by weight is used. If the concentration as chloroacetic acid is less than 40% by weight, the drug concentration in the system will decrease and the effective utilization rate of the etherification agent will decrease, and if it exceeds 70% by weight, the etherification agent will not be uniformly dispersed. Moreover, the alkali cellulose is destroyed and it becomes difficult to uniformly etherify it, which is not preferable. Further, the weight ratio of the total amount of water-containing organic solvent to cellulose is adjusted to be 3.5:1 to 7:1 in order to obtain homogeneous CMC. The weight ratio of the total amount of water-containing organic solvent to cellulose is
If it is less than 3.5:1, the amount of solvent for dissolving the alkali necessary for alcelization is insufficient, so it is necessary to reduce the amount of alkali or increase the water content in the water-containing organic solvent. If the amount of alkali is decreased, it may not be possible to perform sufficient alcelization, or the desired degree of substitution may be restricted, and if the content of water in the water-containing organic solvent is increased, a suitable solvent composition may not be maintained. First, the etherification becomes non-uniform and the organic utilization rate of the etherification agent decreases, which is undesirable. Furthermore, if the amount of solvent is small, mechanical stirring becomes difficult and it becomes difficult to obtain homogeneous CMC, which is not preferable. The CMC obtained by the method of the present invention as described above has a degree of substitution of 0.5 to 1.7, and the viscosity depends on the degree of substitution,
The apparent viscosity can vary slightly depending on the degree of polymerization of the cellulose raw material, the subsequent viscosity reduction operation, etc., but at an anhydride concentration of 1% by weight, the apparent viscosity can be up to about 10,000 milliPascals/second. Next, the present invention will be explained in more detail using Examples, but the present invention is not limited to these Examples. Example 1 1.04 kg of sodium hydroxide is added to 9.6 kg of a water-containing organic solvent consisting of 87% by weight of 2-propanol and 13% by weight of water.
was dissolved to obtain a sodium hydroxide solution for arcelization. Next, the obtained sodium hydroxide solution for arcelization and the crushed linter pulp (average degree of polymerization)
2400) 3Kg was mixed in a kneader and further heated at 25℃.
The alkali cellulose was obtained by stirring for 90 minutes to perform alcelization. Next, 87% by weight of 2-propanol and 13% by weight of water.
1.35kg of chloroacetic acid in 1.35kg of water-containing organic solvent
After dissolving Kg, 50% to neutralize some of it.
Add 0.248 kg of sodium hydroxide aqueous solution (neutralization rate 21.6 mol%) dropwise, maintain the liquid temperature below 30°C, and completely dissolve the resulting etherification agent.
It was added to alkali cellulose while keeping the temperature below 30°C. (During the addition, it was cooled with 7°C brine.) Next, the temperature was raised to 70°C in about 20 minutes, and then further heated to 70°C.
Etherization was carried out for 90 minutes. After etherification, neutralize with acetic acid and add 75% by weight methanol aqueous solution.
After refining three times at 80℃, drying and crushing
I got CMC. The physical properties of the obtained CMC were measured by the following methods: degree of substitution, viscosity, clarity of aqueous solution, amount of glucose produced, amount of free fibers, and amount of gelled material. The results are shown in Table 1. (a) Degree of substitution Accurately weigh 1 g of CMC (anhydride), put it in a porcelain crucible, incinerate it at 560-600℃, add an excess amount of 0.1N sulfuric acid aqueous solution to the sodium oxide produced by the ashing, and add phenolphthalein. Excess sulfuric acid is back-titrated with 0.1N potassium hydroxide aqueous solution using as an indicator, and the degree of substitution is determined from the following formula. (degree of substitution) = 162 x (B-A) f/10000-80 x (B
-A) f (where A is the titer of 0.1N potassium hydroxide aqueous solution (ml), f is the titer of 0.1N potassium hydroxide aqueous solution, and B is the titer of 0.1N potassium hydroxide aqueous solution in the blank test) (b) Viscosity Accurately weigh 2.2g of CMC (anhydrous), prepare and dissolve it in a container with an inner diameter of 55mm and a depth of 115mm to make a 1% aqueous solution using pure water. Determine the viscosity after rotating for 3 minutes at 60 rpm using a BM type viscometer in a constant temperature water bath at 0.2°C. (c) Transparency of aqueous solution Transparency is the visibility of a 1% CMC aqueous solution under a constant light source, expressed as the height of the liquid column. This method is a method commonly used in the art, and if the reaction is non-uniform, the transparency will decrease due to unreacted cellulose, undissolved parts, swollen gel bodies, etc., and the transparency value will become small. Therefore, the higher the uniformity of the reaction, the higher the solution transparency. (d) Glucose production amount Accurately weigh 0.5g of CMC (anhydride) and add approximately 50ml of water.
After adding and dissolving, add 10 ml of acetate buffer solution of PH 4.5 and water to make 100 ml. To 4 ml of this aqueous solution, add an aqueous solution of cellulase (Cellulase AP manufactured by Amano Pharmaceutical Co., Ltd.) in an amount equivalent to 5 mg of cellulase/1 g of CMC, mix thoroughly, and then heat at 40 ± 0.2°C.
Hydrolyze for 72 hours. The amount of glucose produced is
It was quantified by the Nelson-Somogyi method. Units are expressed in cells/1000 anhydroglucose units of cellulose. The amount of glucose produced by enzymatic hydrolysis is said to be a guideline for the substituent distribution of cellulose ethers, including CMC. That is, it is said that this type of cellulase is hydrolyzed to produce glucose when three or more consecutive unsubstituted anhydroglucose units are present. (MG Willik, Journal of Polymer Science., Part A-1, Volume 6, Page 1705, Page 1965, (Published in 1968)
(MGWirick, J.Poly.Sci., PART A-1,
6, 1705, 1965 (1968)), the smaller the amount of glucose produced, the more uniform the substituent distribution. (e) Amount of free fibers Accurately weigh 10g of CMC (anhydrous) and bring the concentration to 10 with water.
% and adjust the pH with acetate buffer solution.
4.5, add the cellulase aqueous solution in an amount equivalent to 5 mg of cellulase/1 g of CMC, mix thoroughly, and then hydrolyze at 40±0.2°C for 72 hours. The solution is filtered through a G-4 glass filter, thoroughly washed and dried, the glass filter is accurately weighed, and the amount of free fibers is determined by the following formula. Amount of free fiber in CMC (mg/100g
CMC) = (B-A)/C x 100000 (In the formula, A and B indicate the weight of the glass filter before and after filtration (g), and C indicates the amount of CMC sample (g).) (Free fibers represent unreacted cellulose. The smaller the amount of free fiber, the better.Cellulase AP has so-called "CMCase" activity (activity to hydrolyze CMC)
is higher than "avicerase" activity (high activity to hydrolyze highly crystalline cellulose, but low activity to hydrolyze water-soluble cellulose derivatives such as CMC), and under the above conditions, CMC is more active than cellulose hydrolysis. It is a cellulase with high hydrolysis activity. ) (f) Amount of glutinated substance Take CMC 1% aqueous solution into a centrifuge tube and spin at 15000 rpm.
After centrifuging for 90 minutes, remove the gel part,
Weigh dry and determine the weight percentage based on dry matter. The lower this value is, the more uniformly the reaction progressed. The transparency of the aqueous solution, the amount of glucose produced, the amount of free fibers, and the amount of gelled material are considered to be properties for evaluating the uniformity of the etherification reaction, and it is desirable that these four are in a well-balanced form. Example 2 Ethanol 60% by weight, benzene 25% by weight, water 15%
1.04 kg of sodium hydroxide was dissolved in 12 kg of a water-containing organic solvent consisting of % by weight to obtain a sodium hydroxide solution for arcelization. Next, the obtained sodium hydroxide solution for arcelization and the crushed linter pulp (average degree of polymerization)
2400) 3Kg was mixed in a kneader and further heated at 25℃.
The alkali cellulose was obtained by stirring for 90 minutes to perform alcelization. Next, 1.358 kg of chloroacetic acid was dissolved in 1.35 kg of a water-containing organic solvent consisting of 60% by weight of ethanol, 25% by weight of benzene, and 15% by weight of water, and then 0.248 kg of 50% aqueous sodium hydroxide solution was added to partially neutralize it.
(neutralization rate 21.6 mol%) was added dropwise and completely dissolved while keeping the liquid temperature below 30°C. The resulting etherifying agent was added to the alkali cellulose while keeping the internal temperature below 30°C. (During the addition, it was cooled with brine at 7°C.) Next, the temperature was raised to about 68°C over about 20 minutes, and etherification was further carried out at this temperature for 90 minutes. After the etherification was completed, it was neutralized with acetic acid, purified three times with a 75% methanol aqueous solution (80% by weight), dried, and ground.
I got CMC. The physical properties of the obtained CMC were measured in the same manner as in Example 1. The results are shown in Table 1. Example 3 87% by weight of 2-propanol used in Example 1,
Instead of 9.6Kg of a water-containing organic solvent consisting of 13% by weight of water, 12Kg of a water-containing organic solvent consisting of 84% by weight of 2-propanol, 3% by weight of methanol, and 13% by weight of water, and 87% by weight of 2-propanol and 13% by weight of water. CMC was obtained in the same manner as in Example 1 except that 0.74 kg of a water-containing organic solvent consisting of 85% by weight of methanol and 15% by weight of water was used instead of 1.35Kg of a water-containing organic solvent consisting of 85% by weight of methanol and 15% by weight of water. The physical properties of the obtained CMC were measured in the same manner as in Example 1. The results are shown in Table 1. Example 4 Ethanol 60% by weight, benzene 25% by weight, water 15%
A sodium hydroxide solution for arcelization was obtained by dissolving 1.56 kg of sodium hydroxide in 12 kg of a water-containing organic solvent consisting of % by weight. Next, the obtained sodium hydroxide solution for arcelization and the crushed linter pulp (average degree of polymerization)
2400) 3Kg was mixed in a kneader and further heated at 25℃.
The alkali cellulose was obtained by stirring for 90 minutes to perform alcelization. Next, 2.211 kg of chloroacetic acid was dissolved in 1.50 kg of a water-containing organic solvent consisting of 85% by weight of ethanol and 15% by weight of water, and then 0.654 kg of a 50% aqueous sodium hydroxide solution (neutralization rate: 34.9 mol) was dissolved in order to partially neutralize it. %) was added dropwise, and the etherifying agent was completely dissolved by keeping the liquid temperature below 30°C, and the resulting etherifying agent was added to the alkali cellulose while keeping the internal temperature below 30°C. (During the addition, it was cooled with 75°C brine.) Next, the temperature was raised to 68°C in about 20 minutes, and then further heated to 68°C.
Etherization was carried out for 90 minutes. After etherification, neutralize with acetic acid and add 75% by weight ethanol aqueous solution 80%
After purification three times, CMC was obtained by drying and pulverizing. The physical properties of the obtained CMC were measured in the same manner as in Example 1. The results are shown in Table 1. Example 5 18.6 kg of a water-containing organic solvent consisting of 87% by weight of 2-propanol and 13% by weight of water and 1.65 kg of sodium hydroxide
was dissolved to obtain a sodium hydroxide solution for arcelization. Next, the obtained sodium hydroxide solution for arcelization and the ground linter pulp (average degree of polymerization
2400) 3Kg was mixed in a kneader and further heated at 25℃.
Alkali cellulose was obtained by stirring for 90 minutes to perform arcelization. Next, 1.5% water-containing organic solvent consisting of 84% by weight of 2-propanol, 3% by weight of methanol, and 13% by weight of water.
After dissolving 2.211Kg of chloroacetic acid in Kg, 50% aqueous sodium hydroxide solution was added to partially neutralize it.
Add 0.474Kg (neutralization rate 25.3mol%) and lower the liquid temperature.
The etherification agent obtained by completely dissolving the agent at 30°C was added to the alkali cellulose while maintaining the system temperature below 30°C. (During the addition, it was cooled with 7℃ brine.) Next, the temperature was raised to 70℃ in about 20 minutes, and then further heated to 70℃.
Etherization was carried out for 90 minutes. After etherification, neutralize with acetic acid and add 75% methanol aqueous solution 80% by weight.
After purification three times, CMC was obtained by drying and pulverizing. The physical properties of the obtained CMC were measured in the same manner as in Example 1. The results are shown in Table 1. Example 6 Ethanol 60% by weight, benzene 25% by weight, water 15%
1.69 kg of sodium hydroxide was dissolved in 15 kg of a water-containing organic solvent consisting of % by weight to obtain a sodium hydroxide solution for arcelization. Next, the obtained sodium hydroxide solution for arcelization and the crushed linter pulp (average degree of polymerization)
2400) 3Kg was mixed in a kneader and further heated at 25℃.
The alkali cellulose was obtained by stirring for 90 minutes to perform alcelization. Next, 2.632 kg of chloroacetic acid was dissolved in 2.63 kg of a water-containing organic solvent consisting of 85% by weight of ethanol and 15% by weight of water, and then 0.538 kg of sodium hydroxide (neutralization rate: 48.3 mol%) was added to partially neutralize it. The etherifying agent obtained by adding and completely dissolving was added to the alkali cellulose while keeping the temperature inside the system at 30°C or less. (During the addition, it was cooled with 7°C brine.) Next, the temperature was raised to 68°C in about 20 minutes, and then further to 68°C.
Etherization was carried out for 90 minutes. After etherification, neutralize with acetic acid and add 75% methanol aqueous solution 80% by weight.
After purification three times, CMC was obtained by drying and pulverizing. The physical properties of the obtained CMC were measured in the same manner as in Example 1. The results are shown in Table 1. Example 7 1.04 kg of sodium hydroxide in 30.0 kg of a water-containing organic solvent consisting of 87% by weight of 2-propanol and 13% by weight of water
was dissolved to obtain a sodium hydroxide solution for arcelization. Next, the obtained sodium hydroxide solution for arcelization and the crushed linter pulp (average degree of polymerization)
2400) 3Kg was mixed in a kneader and further heated at 25℃.
Alkali cellulose was obtained by stirring for 90 minutes to perform alcelization. Next, 87% by weight of 2-propanol and 13% by weight of water.
1.35kg of chloroacetic acid in 1.35kg of aqueous organic solvent
After dissolving Kg, 50% to neutralize some of it.
Add 0.248 kg of sodium hydroxide aqueous solution (neutralization rate 21.6 mol%) dropwise, maintain the liquid temperature below 30°C, and completely dissolve the resulting etherification agent.
It was added to alkali cellulose while keeping the temperature below 30°C. (During the addition, it was cooled with 7°C brine.) Next, the temperature was raised to 70°C in about 20 minutes, and then further heated to 70°C.
Etherization was carried out for 90 minutes. After etherification, neutralize with acetic acid and add 75% methanol aqueous solution 80% by weight.
After purification three times, CMC was obtained by drying and pulverizing. The physical properties of the obtained CMC were measured in the same manner as in Example 1. The results are shown in Table 1. Example 8 1.04 kg of sodium hydroxide in 12.0 kg of a water-containing organic solvent consisting of 68% by weight of 2-propanol and 32% by weight of water
was dissolved to obtain a sodium hydroxide solution for arcelization. Next, the obtained sodium hydroxide solution for arcelization and the crushed linter pulp (average degree of polymerization)
2400) 3Kg was mixed in a kneader and further heated at 25℃.
The alkali cellulose was obtained by stirring for 90 minutes to perform alcelization. Next, 68% by weight of 2-propanol and 32% by weight of water.
1.35kg of chloroacetic acid in 1.35kg of water-containing organic solvent
After dissolving Kg, 0.248 Kg of 50% sodium hydroxide aqueous solution (neutralization rate 21.6 mol%) was added dropwise to partially neutralize it, and the temperature was kept below 30°C to completely dissolve it. Add the etherification agent to the system temperature at 30℃.
It was added to alkali cellulose while maintaining the following. (During the addition, it was cooled with 7°C brine.) Next, the temperature was raised to 70°C in about 20 minutes, and then further heated to 70°C.
Etherization was carried out for 90 minutes. After etherification, neutralize with acetic acid and add 75% methanol aqueous solution 80% by weight.
After purification three times, CMC was obtained by drying and pulverizing. The physical properties of the obtained CMC were measured in the same manner as in Example 1. The results are shown in Table 1. Example 9 1.04 kg of sodium hydroxide in 12.0 kg of a water-containing organic solvent consisting of 92% by weight of 2-propanol and 8% by weight of water
was dissolved to obtain a sodium hydroxide solution for arcelization. Next, the obtained sodium hydroxide solution for arcelization and the crushed linter pulp (average degree of polymerization)
2400) 3Kg was mixed in a kneader and further heated at 25℃.
The alkali cellulose was obtained by stirring for 90 minutes to perform alcelization. Next, 92% by weight of 2-propanol and 8% by weight of water.
1.35kg of chloroacetic acid in 1.35kg of water-containing organic solvent
After dissolving Kg, 50% to neutralize some of it.
Add 0.248 kg of sodium hydroxide aqueous solution (neutralization rate 21.6 mol%) dropwise, maintain the liquid temperature below 30°C, and completely dissolve the resulting etherification agent.
It was added to the alkali cellulose while keeping the temperature below ℃. (During the addition, it was cooled with 7°C brine.) Next, the temperature was raised to 70°C in about 20 minutes, and then further heated to 70°C.
Etherization was carried out for 90 minutes. After etherification, neutralize with acetic acid and add 75% methanol aqueous solution 80% by weight.
After purification three times, CMC was obtained by drying and pulverizing. The physical properties of the obtained CMC were measured in the same manner as in Example 1. The results are shown in Table 1. Comparative Example 1 12.0 kg of a water-containing organic solvent consisting of 87% by weight of 2-propanol and 13% by weight of water and 1.164 kg of sodium hydroxide
Kg was dissolved to obtain a sodium hydroxide solution for arcelization. Next, the obtained sodium hydroxide solution for arcelization and the ground linter pulp (average degree of polymerization
2400) 3Kg was mixed in a kneader and further heated at 25℃.
Alkali cellulose was obtained by stirring for 90 minutes to perform arcelization. Next, 87% by weight of 2-propanol and 13% by weight of water.
1.35kg of chloroacetic acid in 1.35kg of water-containing organic solvent
Kg was dissolved. The etherification agent obtained by completely dissolving the liquid temperature below 30℃ is
It was added to alkali cellulose while keeping the temperature below 30°C. (During the addition, it was cooled with 7°C brine.) Next, the temperature was raised to 70°C in about 20 minutes, and then further heated to 70°C.
Etherization was carried out for 90 minutes. After etherification, neutralize with acetic acid and add 75% methanol aqueous solution 80% by weight.
After purification three times, CMC was obtained by drying and pulverizing. The physical properties of the obtained CMC were measured in the same manner as in Example 1. The results are shown in Table 1. Comparative Example 2 1.10 kg of sodium hydroxide was added to 12.0 kg of a water-containing organic solvent consisting of 87% by weight of 2-propanol and 13% by weight of water.
was dissolved to obtain a sodium hydroxide solution for arcelization. Next, the obtained sodium hydroxide solution for arcelization and the crushed linter pulp (average degree of polymerization)
2400) 3Kg was mixed in a kneader and further heated at 25℃.
The alkali cellulose was obtained by stirring for 90 minutes to perform alcelization. Next, 87% by weight of 2-propanol and 13% by weight of water.
1.35kg of chloroacetic acid in 1.35kg of water-containing organic solvent
After dissolving Kg, 50% to neutralize some of it.
Add 0.128 kg of sodium hydroxide aqueous solution (neutralization rate 11.1 mol%) dropwise, maintain the liquid temperature below 30°C to completely dissolve, and use the obtained etherification agent to reduce the system temperature.
It was added to alkali cellulose while keeping the temperature below 30°C. (During the addition, it was cooled with 7°C brine.) Next, the temperature was raised to 70°C in about 20 minutes, and then further heated to 70°C.
Etherization was carried out for 90 minutes. After etherification, neutralize with acetic acid and add 75% methanol aqueous solution 80% by weight.
After purification three times, CMC was obtained by drying and pulverizing. The physical properties of the obtained CMC were measured in the same manner as in Example 1. The results are shown in Table 1. Comparative example 3 Benzene 25% by weight, ethanol 60% by weight, water 15%
1.14 kg of sodium hydroxide was dissolved in 12.0 kg of a water-containing organic solvent consisting of % by weight to obtain a sodium hydroxide solution for arcelization. Next, the obtained sodium hydroxide solution for arcelization and the crushed linter pulp (average degree of polymerization)
2400) 3Kg was mixed in a kneader and further heated at 25℃.
The alkali cellulose was obtained by stirring for 90 minutes to perform alcelization. Next, 2.211 kg of chloroacetic acid was dissolved in 1.50 kg of a water-containing organic solvent consisting of 25% by weight of benzene, 60% by weight of ethanol, and 15% by weight of water, and then 0.747 kg of sodium hydroxide (neutralized rate
79.8 mol%) was added. When the liquid temperature was kept at 30°C or lower and allowed to stand, salt precipitated. The obtained etherification agent was added to the arcelization reaction solution while maintaining the system internal temperature at 30°C or lower. (During the addition, it was cooled with 7°C brine.) Next, the temperature was raised to 70°C in about 20 minutes, and then further heated to 70°C.
Etherization was carried out for 120 minutes. After etherification, neutralize with acetic acid and add 75% by weight methanol aqueous solution.
After purifying at 80°C three times, drying and pulverizing the CMC
I got it. The physical properties of the obtained CMC were measured in the same manner as in Example 1.

【table】

[Table] [Effects of the invention] According to the method for producing CMC of the present invention, a solution in which chloroacetic acid containing 20 to 60 mol% of an alkali chloroacetic acid salt is completely dissolved in a water-containing organic solvent as an etherification agent is prepared. Because it uses chloroacetic acid alone, it is easier to suppress the heat generation associated with neutralization than when using chloroacetic acid alone, and it also suppresses local destruction of alkali cellulose, resulting in CMC with a uniform degree of substitution distribution. It has the effect of being easily obtained.

Claims (1)

[Claims] 1. A chloromethane used in the production of a carboxymethylcellulose ether alkali salt obtained by etherifying an alkali cellulose obtained by reacting cellulose with an alkali hydroxide in a water-containing organic solvent with an etherification agent. 1. A method for producing a carboxymethyl cellulose ether alkali salt, which comprises using a water-containing organic solvent solution in which 20 to 60 mol% of acetic acid is dissolved as an alkali chloroacetic salt as an etherification agent. 2 The weight ratio of water-containing organic solvent and cellulose is 3.5:
The method for producing a carboxymethylcellulose ether alkali salt according to claim 1, wherein the ratio is 1 to 7:1. 3. The method for producing a carboxymethyl cellulose alkali salt according to claim 1, wherein the organic solvent is a water-containing organic solvent with a weight ratio of 70:30 to 90:10.