JPH09227601A - Production of sulfonated cellulose derivative - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sulfonated cellulose deriv. with a high reaction efficiency and an excellent reaction uniformity at a low cost in an industrial scale by reacting a cellulose compd. with a specific sulfonated conjugated diene in the presence of an alkali substance. SOLUTION: A cellulose compd. is reacted with a sulfonated conjugated diene represented by the formula (wherein R<1> to R<6> are each S03 X, a 1-8C alkyl, or H provided at least one of them is SO3 X; and X is H, an alkali or alkaline earth metal, or ammonium) in the presence of an alkali substance. Examples of the cellulose compd. are cellulose, an alkylcellulose, a hydroxyalkylcellulose, a hydroxyalkylalkylcellulose, and a carboxyalkylcellulose.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a sulfonic acid group-containing cellulose derivative.

[0002]

2. Description of the Related Art Water-soluble cellulose ethers represented by methyl cellulose, hydroxypropyl methyl cellulose, carboxymethyl cellulose, etc.
Has protective colloid properties, surface activity, and film-forming properties,
Used in various industrial fields. However, each of these water-soluble cellulose ethers has merits and demerits, and its improvement is expected. For example, carboxymethyl cellulose is a relatively inexpensive cellulose ether,
It is often used as a fiber paste, a sizing agent for papermaking, and a thickening agent for foods, but since it contains sodium carboxylate base (-COONa) which is a weak acid base in the molecule, the presence of acid or polyvalent metal ion Below, phenomena such as insolubilization or gelation occur, and there are restrictions on the field of application in which it can be actually used. On the other hand, methylcellulose and hydroxypropylcellulose are typical nonionic cellulose ethers, and insolubilization and gelation in the presence of an acid or a polyvalent metal ion as seen in carboxymethylcellulose are unlikely to occur. However, if the aqueous solution is left at a high temperature above a certain level, a so-called thermal gelation phenomenon occurs in which it changes into a gel. Therefore, if there is a step in which a product containing these cellulose ethers is placed in a high temperature atmosphere, these cellulose ethers may gel and the performance may not be sufficiently exhibited.

On the other hand, attempts have been made to introduce a sulfonic acid group or a metal base thereof into a cellulose molecule in order to solve the problem of the water-soluble cellulose ether. Since sulfonic acid is a strong acid unlike carboxylic acid, a cellulose derivative containing a sulfonic acid group or its metal base does not insolubilize or gel even in the presence of an acid or a polyvalent metal ion, and has a heat gelling property. Since it has the feature of not showing, it can be expected to be applied in a fairly wide range of engineering fields.

As sulfonic acid group-containing cellulose derivatives, sulfoethyl cellulose ethers such as sulfoethyl cellulose, sulfoethyl hydroxypropyl cellulose and sulfoethyl carboxymethyl cellulose, and sulfopropyl cellulose ethers such as sulfopropyl cellulose and sulfopropyl methyl cellulose have been known. There is. These cellulose derivatives include cellulose or cellulose ethers such as carboxymethyl cellulose, hydroxypropyl cellulose, and methyl cellulose, vinyl sulfonic acid or a metal salt thereof, β-chloroethanesulfonic acid or a metal salt thereof, and a sulfoalkylating agent such as propane sultone. It can be produced by reacting. However, among these sulfoalkylating agents, vinyl sulfonic acid or its metal salt is generally unstable as an aqueous solution of 30 to 40% because it is unstable by itself. Therefore, water in the reaction system, which is an important factor in the sulfoethylation reaction, cannot be freely controlled, and the efficiency or uniformity of the reaction cannot be increased. Also, β-
At present, chloroethanesulfonic acid or its salt is not commercially available, and even if it is attempted to synthesize it, the productivity is extremely poor, and it is practically difficult to use it as a raw material for industrial production. Propane sultone is commercially available, but its price is extremely high, and even if it is used as a sulfoalkylating agent, the production cost of the product is high and it is difficult to carry out industrially.

[0005]

The present invention has been made in view of these problems of the prior art, and is excellent in reaction efficiency and uniformity of reaction, and can be produced at low cost and on an industrial scale. An object is to provide a method for producing a possible sulfonic acid group-containing cellulose derivative.

[0006]

The present invention provides a method for producing a sulfonic acid group-containing cellulose derivative by reacting a cellulose with a sulfonated compound of a conjugated diene represented by the following general formula (1) in the presence of an alkaline substance. To do.

Embedded image (In the formula, R ^{1 to} R ⁶ are —SO ₃ X, an alkyl group having 1 to 8 carbon atoms or a hydrogen atom, and at least one of R ^{1 to} R ⁶ is —SO ₃ X. Here, X Represents a hydrogen atom, an alkali metal atom, an alkaline earth metal atom, or an ammonium group.)

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Cellulose used in the present invention means cellulose or a cellulose derivative obtained by using cellulose as a raw material. As the cellulose, specifically,
It is possible to use wood pulp derived from wood or linter pulp derived from cotton, which contains cellulose in high purity. Further, as the cellulose derivative, it is possible to use those obtained by substituting a part of hydrogen atoms of hydroxyl groups in the cellulose molecule with various substituents, alkyl cellulose,
Examples thereof include hydroxyalkyl cellulose, hydroxyalkylalkyl cellulose, carboxyalkyl cellulose and the like. As alkyl cellulose,
Examples of methyl cellulose, ethyl cellulose and hydroxyalkyl cellulose include hydroxypropyl cellulose and hydroxyethyl cellulose, and examples of hydroxyalkyl alkyl cellulose include hydroxypropyl methyl cellulose, hydroxyethyl methyl cellulose, hydroxyethyl ethyl cellulose and carboxyalkyl cellulose such as carboxymethyl cellulose.

The sulfonated product of the conjugated diene used in the present invention can be produced very easily by reacting the conjugated diene with sulfur trioxide according to the method described in JP-A-1-263103. For example, 2-methyl-1,
3-butanedienesulfonic acid, 1,3-butanedienesulfonic acid, 2-ethyl-1,3-butanedienesulfonic acid, 2,3-dimethyl-1,3-butanedienesulfonic acid, 2-butyl-1, 3-butanedienesulfonic acid, 2
-Hexyl-1,3-butanedienesulfonic acid, 2-methyl-1,3-butanediene-2-sulfonic acid, 4-methyl-1,3-butanediene-2-sulfonic acid, or their alkali metal salts, alkali Examples thereof include earth metal salts and ammonium salts.

The method of reacting the cellulose with the sulfonated product of the conjugated diene in the presence of an alkali is not particularly limited, but generally, the powdery cellulose is dispersed in a hydrophilic solvent, and then an aqueous solution of an alkaline substance is added and mixed. After the alkali cellulose has been obtained, a sulfonated product of a conjugated diene is added and the temperature is raised to a predetermined temperature to react. After the reaction,
After separating the produced sulfonic acid group-containing cellulose derivative and the solvent, the product may be washed and dried.

Examples of the alkaline substance used in the present invention include alkali metal compounds such as sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate, alkaline earth metal hydroxides such as calcium hydroxide and magnesium hydroxide. Can be used. Of these, sodium hydroxide is particularly preferably used.

Examples of the hydrophilic solvent used in the present invention include lower alcohols such as methanol, ethanol and isopropanol, acetone, tetrahydrofuran and dioxane, and these solvents can be used alone or in combination. .

The addition amount of the sulfonated product of the conjugated diene used in the present invention is arbitrarily selected according to the desired degree of sulfonic acid modification, but is 0.1 to 10 times the molar ratio of the starting material cellulose or cellulose derivative per anhydrous glucose unit.
It is preferably double. If it is less than 0.1 times, it will not be water-soluble, and even if it exceeds 10 times, the performance will not be worth the cost increase. The amount of water added during the reaction is 2 to 80 times the molar ratio per anhydroglucose unit of the starting material cellulose or cellulose derivative, and preferably 5 to 40 times the molar ratio per anhydroglucose unit. 2
If it is less than twice, the alkali cellulose becomes non-uniform and a uniform reaction does not occur, and if it exceeds 80 times, the reaction efficiency of the sulfonated product decreases. The addition amount of the alkaline substance used in the present invention is 0.01 to 10 times the molar ratio per anhydroglucose unit of the raw material cellulose or cellulose derivative. If it is less than 0.01 times, the reaction speed becomes slow,
If it exceeds 10 times, hydrolysis of the product will proceed and a high viscosity product cannot be produced. The reaction temperature is from 40 ° C to the boiling point of the solvent. If the temperature is lower than 40 ° C, the reaction rate becomes slow, and if it exceeds the boiling point, a pressure resistant reactor is required, but there is no merit commensurate with it.

Incidentally, when reacting celluloses with a sulfonated product of a conjugated diene, conventionally known etherifying agents such as methyl chloride, ethyl chloride, ethylene oxide, propylene oxide, sodium monochloroacetate and sodium vinyl sulfonate. It is also possible to add and react as necessary.

The manner in which cellulose reacts with the sulfonated product of a conjugated diene is the so-called 1,2-Michael addition reaction or 1,4-Michael addition reaction. For example,
When R ¹ is —SO ₃ X in the above-mentioned conjugated diene sulfonated product, the following sulfonic acid group-containing cellulose derivative is produced.

Embedded image (In the formula, Cell-OH represents celluloses.)

In this case, since the produced sulfonic acid group-containing cellulose derivative contains an ethylenically unsaturated bond, a cross-linking reaction mediated by the ethylenically unsaturated bond may occur depending on the reaction conditions. There is. The present invention also includes secondary reactions of such products.

[0016]

EXAMPLES The present invention will be described below with reference to Examples 1 and 2 and Comparative Example 1, but the present invention is not limited thereto. Example 1 In a reactor equipped with a stirrer and condenser, linter pulp powder (molecular weight per anhydrous glucose unit: 16
2) After dispersing 20.8 g in 200 g of isopropyl alcohol, 30.8% sodium hydroxide aqueous solution 3
0 g was added and stirred for 15 minutes to obtain an alkali cellulose dispersion liquid. Next, while heating this dispersion liquid to reflux isopropyl alcohol (reflux temperature 82 to 84 ° C.),
17.5 g (0.103 mol) of sodium 2-methyl-1,3-butanedienesulfonate (molecular weight: 170) was added, and the mixture was reacted for 2 hours while stirring. The sodium hydroxide in the system was neutralized with acetic acid, the reaction product was filtered, and the filtration residue was removed to 7
The product was washed twice with 0% water-containing methanol, further washed once with methanol, and then dried to obtain 30 g of a product. The degree of etherification (average number of moles of sodium sulfonate contained per anhydroglucose unit of cellulose) of the sulfonic acid-modified cellulose derivative thus produced was measured by the following method, and the value was 0. .4
8 (reaction efficiency 60%), and the aqueous solution was transparent.

(Degree of Etherification) The Na content of a 5 g sample washed with 100 g of 80% water-containing methanol four times was measured by flame photometry, and the degree of etherification was determined by the following formula. Degree of etherification = 162A / (2300-170A) A: Na weight%

Example 2 Hydroxypropylmethyl cellulose (Metronose 60SH-4000 manufactured by Shin-Etsu Chemical Co., Ltd., the number of moles substituted with methoxy group: 1.88) in a reactor equipped with a stirrer and a cooling tube.
The reaction and purification were carried out in the same manner as in Example 1 except that 26 g of powder having a hydroxypropoxyl group substitution molar number of 0.23 and a molecular weight per anhydrous glucose unit of 202) was used to obtain 31.2 g of a product. With respect to the sulfonic acid-modified hydroxypropylmethyl cellulose thus produced, the Na content was measured by the same method as in Example 1, and the etherification degree was calculated by the following formula:
It was 0.32 (reaction efficiency 40%), and the aqueous solution was transparent. Degree of etherification = 202A / (2300-170A) A: Na weight%

Comparative Example 1 Instead of 17.5 g of sodium 2-methyl-1,3-butanedienesulfonate in Example 1, 34% aqueous solution of sodium vinylsulfonate (molecular weight: 130) 3
The reaction was performed in the same manner as in Example 1 except that 9.4 g (0.103 mol) was used. When the degree of etherification of the obtained sulfonic acid-modified cellulose derivative was measured, the value was 0.19 (reaction efficiency 23%), and the aqueous solution was white and turbid, and the reaction was nonuniform. all right. Degree of etherification = 162A / (2300-130A) A: Na weight%

[0020]

The conventional reaction efficiency is about 20%, and the conventional reaction is non-uniform, so that the aqueous solution thereof is opaque. INDUSTRIAL APPLICABILITY The present invention overcomes the drawbacks of conventional sulfone alkylating agents as is clear from Examples 1 and 2, and is excellent in reaction efficiency and uniformity of reaction, and can be produced at low cost and on an industrial scale. Provided is a method for producing a sulfonic acid group-containing cellulose derivative.

Claims (2)

[Claims] 1. Cellulose in the presence of an alkaline substance,
A method for producing a sulfonic acid group-containing cellulose derivative, which comprises reacting with a sulfonated compound of a conjugated diene represented by the following general formula (1). Embedded image (In the formula, R ^{1 to} R ⁶ are —SO ₃ X, an alkyl group having 1 to 8 carbon atoms or a hydrogen atom, and at least one of R ^{1 to} R ⁶ is —SO ₃ X. Here, X Represents a hydrogen atom, an alkali metal atom, an alkaline earth metal atom, or an ammonium group.) 2. The method for producing a sulfonic acid group-containing cellulose derivative according to claim 1, wherein the cellulose is cellulose, alkyl cellulose, hydroxyalkyl cellulose, hydroxyalkyl alkyl cellulose, or carboxyalkyl cellulose. .