JP2009114375A - Method for producing cellulose derivative - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a commercially efficient and simple method for producing a cellulose derivative. <P>SOLUTION: In this method for producing a cellulose derivative, a low crystalline powder cellulose is reacted with glycidol in the presence of a catalyst. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a cellulose derivative obtained by reacting glycidol with cellulose.

Hydrophilic cellulose derivatives are used as dispersion stabilizers, thickeners, water retention agents for water-based compositions, or as ingredients of cleaning compositions such as shampoos, rinses, treatments, conditioners, and the like.
A general method for producing a hydrophilic cellulose derivative typified by hydroxyethyl cellulose is not to directly act on a cellulose with a hydrophilizing agent (hydrophilic etherifying agent) such as ethylene oxide. The alkali metal hydroxide such as sodium hydroxide is mixed in a slurry state to form so-called alkali cellulose, which requires an extremely complicated cellulose activation process called arserization or mercerization.
Alkaline cellulose obtained by the arserification treatment is considered to have an alcoholate in most of the hydroxyl groups in the cellulose molecule. Actually, it is usually about 3 mol amount, at least 1 mol per glucose unit in the cellulose molecule. More than the amount of alkali is contained. Cellulose ether can be obtained by adding an etherifying agent to the cellulose activated by this arseration, but water of the same weight or more remaining during the arseration also reacts with ethylene oxide as an etherifying agent (hydration) Therefore, a large amount of by-products such as ethylene glycol is generated. After the reaction, it is necessary to remove not only these by-products but also a large amount of neutralized salts derived from the alkali used for the arseration. Furthermore, since this ethylene oxide is regulated by high-pressure gas, there are many facilities restrictions from an industrial viewpoint.

  On the other hand, the introduction of a glyceryl group having higher hydrophilicity than a hydroxyethyl group as a substituent, that is, a liquid phase reaction using glycidol as a hydrophilic etherifying agent instead of ethylene oxide has also been proposed. For example, Non-Patent Document 1 discloses a homogeneous reaction method in which dimethylacetamide containing lithium chloride is used as a solvent and a base catalyst is further added to add glycidol to cellulose. However, in this method, pretreatment such as dehydration is necessary for dissolution of cellulose, and there are many problems from an industrial viewpoint, such as low reaction efficiency of glycidol to cellulose.

Patent Document 1 discloses a homogeneous reaction method in which dimethylacetamide containing a quaternary ammonium halide such as tetrabutylammonium fluoride is used as a solvent, and a basic catalyst is further added to add glycidol to cellulose. ing. However, in this method, the quaternary ammonium halide to be used is very expensive, and like the above-described method, the solubility of cellulose is not sufficient, so a large amount of solvent is required, and from an industrial viewpoint such as productivity. There are many challenges.
Therefore, the development of a simple and efficient method for adding glycidol to cellulose is an extremely useful problem as a means for imparting a hydrophilic group of cellulose from an industrial viewpoint.

JP 2007-238656 A Makromol. Chem. , 93 (3), 647 (1992)

  An object of this invention is to provide the manufacturing method of a cellulose derivative which is industrially simple and efficient.

The present inventors have found that the catalytic reaction with glycidol proceeds very efficiently by using powdered cellulose having a reduced crystallinity.
That is, the present invention is a method for producing a cellulose derivative represented by the following general formula (1), in which low crystalline powdery cellulose is reacted with glycidol in the presence of a catalyst.

(In the formula, R represents a hydrogen atom or a substituent represented by the following general formula (2) or (3), and R does not become a hydrogen atom. N represents a number of 100 to 2000.)

  According to the present invention, an industrially simple and efficient method for producing a cellulose derivative can be provided.

The present invention is a method for producing a cellulose derivative represented by the general formula (1), wherein low crystalline powdery cellulose is reacted with glycidol in the presence of a catalyst.
Hereinafter, the production method of the present invention will be described in detail.

[Preparation of low crystalline powdered cellulose]
In general, cellulose has several known crystal structures, and is defined as the crystallinity from the ratio of the amorphous part and the crystal part present in a part. The “crystallinity” in the present invention is natural. The degree of crystallinity of type I derived from the crystal structure of cellulose is shown, and is defined by the degree of crystallinity represented by the following formula (1) obtained from the powder X-ray crystal diffraction spectrum.
Crystallinity (%) = [(I _22.6 −I _18.5 ) / I _22.6 ] × 100 Formula (1)
[I _22.6 is the diffraction intensity of the lattice plane (002 plane) (diffraction angle 2θ = 22.6 °) in X-ray diffraction, and I _18.5 is the diffraction intensity of the amorphous portion (diffraction angle 2θ = 18.5 °). Show
Further, the “low crystallinity” of the low crystalline powdery cellulose in the present invention indicates a state in which the ratio of the amorphous part is large in the crystal structure of the above cellulose, and preferably the crystallization obtained from the above formula (1). The degree is desirably 50% or less.
Since generally known powdered cellulose also has a very small amount of amorphous part, the crystallinity thereof is generally included in the range of 60 to 80% according to the calculation formula (1) used in the present invention. The so-called crystalline cellulose is extremely low in reactivity in the synthesis of cellulose derivatives.

  The low crystalline powdery cellulose used in the present invention can be prepared very easily from a sheet-like or roll-like pulp having a high cellulose purity obtained as a general-purpose raw material. The method for preparing the low-crystalline powdery cellulose is not particularly limited. For example, JP-A-62-236801, JP-A-2003-64184, JP-A-2004-331918, etc. Mention may be made of the preparation methods described.

Moreover, for example, the method of preparing by processing the chip-like pulp obtained by roughly pulverizing the sheet-like pulp with an extruder and further with a ball mill can also be mentioned.
As the extruder used in this method, a single-screw or twin-screw extruder can be used, and from the viewpoint of applying a strong compressive shear force, a so-called kneading disk portion is provided in any part of the screw. There may be. Although there is no restriction | limiting in particular as a processing method using an extruder, The method of throwing chip-like pulp into an extruder and processing continuously is preferable.
As the ball mill, a known vibration ball mill, medium stirring mill, rolling ball mill, planetary ball mill, or the like can be used. There is no restriction | limiting in particular in the material of the ball | bowl used as a medium, For example, iron, stainless steel, an alumina, a zirconia etc. are mentioned. The outer diameter of the ball is preferably 0.1 to 100 mm from the viewpoint of efficiently amorphizing the cellulose. In addition to the ball, a medium such as a rod or tube can be used as the medium.
The treatment time of the ball mill is preferably 5 minutes to 72 hours from the viewpoint of reducing the crystallinity. In this treatment, in order to minimize denaturation and deterioration due to generated heat, the treatment is preferably performed at 250 ° C. or less, preferably in the range of 5 to 200 ° C., and further if necessary. , Under an inert gas atmosphere such as nitrogen.
By using the method as described above, it is possible to control the molecular weight, and it is possible to easily prepare powdered cellulose having a high degree of polymerization and low crystallinity, which is generally difficult to obtain. As, it is 100-2000, More preferably, it is 100-1000.

The crystallinity of the low-crystalline powdery cellulose used in the present invention is preferably 50% or less as determined from the above formula (1). If this crystallinity is 50% or less, the reaction with glycidol proceeds very well. In this respect, 40% or less is more preferable, and 30% or less is still more preferable. In particular, in the present invention, it is most preferable to use amorphous cellulose that has been completely amorphized, that is, the degree of crystallinity obtained from the above formula is approximately 0%.
The average particle size of the low-crystalline powdery cellulose is not particularly limited as long as it can maintain a good fluidity as a powder. However, in general reaction conditions in the present invention, 300 μm or less is preferable, and 20 to 150 μm is preferable. More preferably, 25-50 micrometers is still more preferable.

(Production of cellulose derivative)
In the present invention, the low-crystalline powdery cellulose obtained above is reacted with glycidol in the presence of a catalyst to produce a cellulose derivative represented by the general formula (1) (hereinafter simply referred to as “cellulose derivative”). There is).

In the general formula (1), R represents a hydrogen atom or a substituent (glyceryl group) represented by the general formula (2) or (3), and all of R does not become a hydrogen atom. N is in the range of 100 to 2000, preferably 100 to 1000.
In the cellulose derivative represented by the general formula (1), the substitution degree per glucose unit in the cellulose of the substituent represented by the general formula (2) or (3) to be introduced is set to a desired substitution degree. However, the degree of substitution is preferably 0.01 to 3, and more preferably 0.2 to 2. In addition, the said substitution degree is measured by the method shown in an Example.

The amount of glycidol used in the present invention is preferably in the range of 0.01 to 3 mol times, more preferably in the range of 0.2 to 2 mol times per glucose unit in the cellulose molecule. When the amount of glycidol used is within this range, the reaction efficiency of glycidol with respect to cellulose is extremely high, so that a cellulose derivative having a desired degree of substitution can be obtained, and further addition of the introduced glyceryl group to the hydroxyl group is suppressed. be able to.
If glycidol is used in an amount of more than 3 moles per glucose unit in the cellulose molecule, glycidol is added to the glyceryl group, so that a polyglyceryl group can be introduced onto the cellulose.

  Although there is no restriction | limiting in particular as a catalyst used by this invention, A base catalyst or an acid catalyst can be used. Examples of the base catalyst include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide and lithium hydroxide, alkaline earth metal hydroxides such as magnesium hydroxide and calcium hydroxide, trimethylamine, triethylamine, triethylenediamine and the like 3 Secondary amines. Examples of the acid catalyst include Lewis acid catalysts such as lanthanide triflate. Of these, basic catalysts are preferred, alkali metal hydroxides are particularly preferred, and sodium hydroxide and potassium hydroxide are most preferred. These catalysts can also be used 1 type or in combination of 2 or more types.

The catalyst can be added by adding an aqueous solution or dilute solution to remove the excess water, and then reacting. However, the reaction state should be in a slurry state or in a high viscosity state. Therefore, it is preferable to maintain a fluid powder state, and therefore, the water content when added in a dilute aqueous solution is preferably 100% by weight or less based on cellulose.
The amount of catalyst used is sufficient for both cellulose and glycidol. Specifically, an amount corresponding to 0.1 to 50 mol% per glucose unit in the cellulose molecule is preferable. Is more preferably an amount corresponding to 1 to 30 mol%, and most preferably an amount corresponding to 5 to 25 mol%.

The reaction between cellulose and glycidol in the present invention is preferably carried out while maintaining the powder state as described above, but it can also be carried out in a dispersed state using a non-aqueous polar solvent.
Examples of non-aqueous polar solvents include secondary or tertiary lower alcohols such as isopropanol and tert-butanol that are generally used in the process of arseling; diglyme such as 1,4-dioxane, ethylene glycol dimethyl ether, and diethylene glycol dimethyl ether; Examples include ether solvents such as triglyme and polyethylene glycol dimethyl ether; and hydrophilic polar solvents such as dimethyl sulfoxide. On the other hand, general low-polarity or nonpolar solvents such as toluene, benzene, hexane, and other hydrocarbon oils can also be used as long as the effects of the present invention are not impaired.
As the amount of non-aqueous solvent used, it is not necessary to dissolve cellulose, so pretreatment as described in the above-mentioned literature is not necessary, and it can be added as it is without using a large amount, but the catalyst is diluted. From the standpoint of avoiding a decrease in reactivity, it is preferably 10 times by weight or less than cellulose.

The method for adding glycidol in the present invention is not particularly limited. For example, (a) a method in which a catalyst is added to cellulose and then glycidol is gradually dropped to react, and (b) glycidol is added to cellulose in a lump. The method of adding a catalyst and making it react is mentioned. Among these, the method (a) is more preferable from the viewpoint of avoiding polymerization of glycidol itself.
In any method, the water content in the reaction system is preferably 100% by weight or less based on cellulose. If the moisture content with respect to cellulose is within this range, the cellulose can be reacted in a fluid powder state without excessive aggregation. In this respect, 80% by weight or less is more preferable, and 5 to 50% by weight is most preferable.
For this reason, when the catalyst is added as an aqueous solution, for example, in the method (a), dehydration is simultaneously performed while the reaction proceeds by dropwise addition of glycidol, and the water content in the reaction system is adjusted to the above-described range. It is also possible.

In the present invention, since the reaction selectivity of glycidol to cellulose is extremely high, it is not necessary to use glycidol in excess for the desired degree of substitution. That is, there are very few by-products of hydrates and polymers such as glycerin and polyglycerin obtained as by-products derived from glycidol. Therefore, glycerylation can be performed with a desired degree of substitution.
In a normal glycerylation reaction, a base such as an alkali used in the reaction is removed as a neutralized salt after the reaction is completed. However, since the reaction in the present invention is a catalytic reaction, neutralization derived from the catalyst is performed. The amount of salt can also be reduced. In other words, since there are very few by-products and wastes derived from glycidol and catalyst, purification after completion of the reaction (such as washing) is facilitated, and industrial utility is extremely high.

In the present invention, it is preferable to react a mixture of low-crystalline cellulose, catalyst and glycidol in a fluid powder state, but the cellulose powder and catalyst or glycidol are required in advance by a mixer or shaker such as a mixer. It is also possible to carry out the reaction after mixing and dispersing uniformly according to the above.
As the reaction apparatus that can be used in the present invention, one that can mix low-crystalline cellulose, catalyst, and glycidol as uniformly as possible is preferable. In addition to the mixer such as the mixer described above, paragraphs of JP-A-2002-114801 A mixer such as a so-called kneader used for kneading resin or the like as disclosed in [0016] is most preferable.
The reaction temperature in the present invention is preferably in the range of 0 to 150 ° C, more preferably in the range of 10 to 100 ° C, and particularly preferably in the range of 20 to 80 ° C from the viewpoint of avoiding the polymerization of glycidol itself.
Moreover, it is preferable that reaction in this invention is performed under a normal pressure. Moreover, it is preferable to carry out in inert gas atmosphere, such as nitrogen, as needed from a viewpoint of avoiding the coloring at the time of reaction.
After completion of the reaction, the product is neutralized with an acid or an alkali, washed with water-containing isopropanol, water-containing acetone solvent, etc., if necessary, and then dried, and expressed by the general formula (1). A cellulose derivative can be obtained.

  In the present invention, the substituent represented by the general formula (2) or (3) may be bonded to the hydroxyl group at any position in the glucose unit in the cellulose molecule. It is possible to adjust. From this, the cellulose derivative obtained by this invention can be utilized for uses, such as compounding components, such as a dispersion stabilizer of an aqueous composition, a thickener, a water retention agent, a shampoo, rinse, and a conditioner.

(1) Moisture content with respect to cellulose The moisture content with respect to cellulose was measured at 150 ° C. using “FD-610” manufactured by Kett Scientific Laboratory as an infrared moisture meter.
In order to confirm the optimal moisture content of cellulose in the present invention, a predetermined amount of water was added to the non-crystalline cellulose obtained by the method according to Production Example 1 described later, and then vigorously stirred and shaken. Thus, the aggregation state was repeatedly observed.
As a result, in order to react cellulose in a fluid powder state, it was determined that the water content was preferably 100% by weight or less. The results are shown in Table 1.

(2) Calculation of crystallinity The crystallinity of cellulose is calculated according to the above formula from the peak intensity of the diffraction spectrum measured under the following conditions using “Rigaku RINT 2500VC X-RAY diffractometer” manufactured by Rigaku Corporation. It was.
X-ray source: Cu / Kα-radiation, tube voltage: 40 kv, tube current: 120 mA, measurement range: 2θ = 5-45 °, measurement sample: produced by compressing pellets of area 320 mm ² × thickness 1 mm, X-ray Scan speed: 10 ° / min
(3) Measurement of degree of polymerization of powdered cellulose The degree of polymerization of powdered cellulose was measured by the copper ammonia method described in ISO-4312 method.
(4) Calculation of the degree of substitution The degree of substitution indicates the average amount of glyceryl groups introduced per unit of glucose in cellulose, and the analysis of the product (degree of substitution, etc.) is carried out by conventional methods using acetic anhydride / pyridine. The acetylated product was subjected to various NMR analysis.
(5) Measurement of average particle diameter of powdered cellulose The average particle diameter of powdered cellulose was measured using a laser diffraction / scattering particle size distribution measuring apparatus “LA-920” manufactured by Horiba, Ltd.

Production Example 1 (Production of low crystalline powdered cellulose)
A wood pulp sheet (Bolleguard's pulp sheet, crystallinity 74%) was shredded (manufactured by Meiko Shokai Co., Ltd., “MSX2000-IVP440F”) into a chip shape.
Next, the obtained chip-like pulp was charged into a twin screw extruder (“EA-20” manufactured by Suehiro EPM Co., Ltd.) at 2 kg / hr, a shear rate of 660 sec ⁻¹ , a screw rotation speed of 300 rpm, and cooling water from the outside. The powder was processed by one pass while flowing.
Next, the obtained powdered cellulose was put into a batch-type medium stirring mill (“Sand grinder” manufactured by Igarashi Machine Co., Ltd .: container volume 800 mL, filled with 720 g of 5 mmφ zirconia beads, filling rate 25%, stirring blade diameter 70 mm). While passing cooling water through the container jacket, the mixture is pulverized for 2.5 hours at a stirring speed of 2000 rpm and a temperature of 30 to 70 ° C. to obtain powdered cellulose (crystallinity 37%, polymerization degree 500, average particle size 40 μm). Got. For the reaction of the powdered cellulose, an unsieved product (90% of the input amount) with a sieve having an opening of 32 μm was used.
In addition, powdered cellulose with different crystallinity was prepared by changing the treatment time in the ball mill treatment.

Example 1
In a 1 L kneader (manufactured by Irie Shokai Co., Ltd., PNV-1 type), 100 g of low crystalline cellulose (crystallinity 37%, polymerization degree 500) obtained in Production Example 1 and 37 g of glycidol (0.50 mol) were obtained. In addition, the mixture was stirred at room temperature for 2 hours under a nitrogen atmosphere. Next, 5.8 g of a 48% sodium hydroxide aqueous solution was sprayed and added with stirring, the temperature was raised to 50 ° C., and the reaction was allowed to proceed for 6 hours. During the reaction, the cellulose maintained a fluid powder state. Then, after neutralizing with acetic acid and taking out the product from the kneader, it was washed with hydrous isopropanol (water content 15%) and acetone, and dried under reduced pressure to obtain a cellulose derivative as 130 g of a white solid. The degree of substitution of glyceryl group on cellulose was 0.72, and the reaction rate of glycidol to cellulose was 90%.

Comparative Example 1
The reaction is performed in the same manner as in Example 1 except that highly crystalline powdery cellulose (cellulose powder KC Flock W-50 (S); crystallinity 74%, polymerization degree 500) manufactured by Nippon Paper Chemical Co., Ltd. is used as cellulose. However, no increase in the weight of the product was observed, the degree of substitution of glyceryl groups on cellulose was 0.02, and the reaction rate of glycidol to cellulose was only 2%.

Example 2
The reaction was conducted in the same manner as in Example 1 except that 400 ml of polyethylene glycol dimethyl ether (Merck reagent, polyethylene glycol dimethyl ether 500) was added as a solvent, and the reaction time was 20 hours. Was in good condition. The degree of substitution of glyceryl group on cellulose was 0.74, and the reaction rate of glycidol to cellulose was 91%.

Comparative Example 2
The reaction is carried out in the same manner as in Example 2 except that highly crystalline powdery cellulose (cellulose powder KC Flock W-50 (S); crystallinity 74%, polymerization degree 500) manufactured by Nippon Paper Chemical Co., Ltd. is used as cellulose. The reaction of glycidol to cellulose was not confirmed at all.

  In Examples 1 and 2, the reaction rate of glycidol to cellulose is improved as compared with Comparative Examples 1 and 2, and a cellulose derivative having a desired degree of substitution can be efficiently obtained.

  According to the present invention, a cellulose derivative obtained by a reaction between cellulose and glycidol can be produced by an efficient method that is industrially simple and excellent in productivity, and the obtained cellulose derivative is an aqueous composition. It is suitably used for applications such as dispersion stabilizers, thickeners, water retention agents, shampoos, rinses and conditioners.

Claims (6)

A method for producing a cellulose derivative represented by the following general formula (1), wherein low crystalline powdery cellulose is reacted with glycidol in the presence of a catalyst.

(In the formula, R represents a hydrogen atom or a substituent represented by the following general formula (2) or (3), and R does not become a hydrogen atom. N represents a number of 100 to 2000.)

  The method for producing a cellulose derivative according to claim 1, wherein the reaction is carried out in the presence of a catalytic amount of a catalyst.   The method for producing a cellulose derivative according to claim 1 or 2, wherein the crystallinity of the low crystalline powdery cellulose is 50% or less.   The manufacturing method of the cellulose derivative in any one of Claims 1-3 whose water content with respect to low crystalline powdery cellulose is 100 weight% or less.   The manufacturing method of the cellulose derivative in any one of Claims 1-4 made to react using the nonaqueous polar solvent 10 weight times or less with respect to low crystalline powdered cellulose.   The manufacturing method of the cellulose derivative in any one of Claims 1-5 which uses an alkali metal hydroxide as a catalyst.