JP6898093B2 - Method for producing cellulose mixture - Google Patents

Description

The present invention relates to a method for producing a cellulose mixture.

Cellulose derivatives are used as compounding components, dispersants, modifiers, flocculants, etc. of detergent compositions such as shampoos, rinses, treatments, and conditioners, and their uses are wide-ranging. Since cellulose, which is a raw material for producing this cellulose derivative, has high crystallinity and poor reactivity, it is necessary to reduce the crystallinity and improve the reactivity.
Therefore, as a general method for producing a cellulose derivative, a large amount of water and a large excess of alkali metal hydroxide are mixed in a slurry state to obtain an alkali cellulose, which is called cellulose activation or mercellification. After the treatment, cationizing agents such as glycidyltrialkylammonium chloride and hydroxyalkylating agents such as alkylene oxide (hereinafter, compounds such as cationizing agents and hydroxyalkylating agents used for derivatizing cellulose are collectively referred to as " A method of derivatizing by reacting with a "reactant") is known. However, since a large excess of alkali is used in this method, the reaction selectivity of the reactant is low, and a large amount of salt is by-produced, and the purification load for removing the by-product salt becomes a problem.

Therefore, there is also known a method in which the crystallinity of cellulose is lowered in advance by a mechanochemical method using a ball mill, a rod mill, or the like, and then the cellulose is derivatized. Since this method requires only a small amount of alkali to activate cellulose, the washing step for removing a large excess of alkali can be omitted, and it is an excellent method that solves the above-mentioned problems related to productivity and efficiency. is there.
For example, as a method for producing hydroxypropyl cellulose (HPC), which is a cellulose derivative, low-crystalline powdered cellulose crushed by mechanical force, alkali metal hydroxide and water in an amount equivalent to the anhydroglucose unit of cellulose are used. A method is known in which the mixture is mixed to obtain alkaline cellulose and then reacted with propylene oxide in a powder state (Patent Document 1). However, when activating cellulose with a small amount of alkali, if the diffusion of the alkali into the cellulose is insufficient, type I crystals of the cellulose tend to remain. When this cellulose is reacted with propylene oxide in a powder state, the reaction does not proceed uniformly because the hydroxypropylation of the reaction-inactive I-type crystal portion does not proceed uniformly, and the water solubility of the obtained hydroxypropyl cellulose also decreases. Sometimes. In order to avoid this, it was necessary to use cellulose whose crystallinity was lowered until almost completely no crystals were used as a raw material.
Further, in the presence of water, a side reaction in which propylene oxide, which is a reactant, is hydrolyzed and increased in quantity may proceed to produce a by-product. If the washing step after the reaction is omitted, there is a problem that the by-product remains in the product and the product purity tends to decrease. Therefore, the occurrence of the side reaction is suppressed and the reaction between the cellulose and the reactant is performed. It is desired to improve the selectivity.

It is also known to produce cellulose derivatives and regenerated cellulose using a cellulose solution, and a method of increasing the solubility of cellulose and obtaining a cellulose solution under mild conditions is being studied. For example, Pat. A method for producing an aqueous cellulose solution is disclosed, wherein the total concentration of halides of similar metals is 1% by weight or less, or the contact is carried out in the presence of cyclic polyether.
Further, Patent Document 3 contains at least one onium hydroxide selected from a quaternary phosphonium hydroxide and a quaternary ammonium hydroxide and water, and has an onium hydroxide content of 45. A method for producing solid cellulose is disclosed, which comprises a step of dissolving cellulose in a solvent having a water content of ~ 85% by weight and a water content of 15 to 55% by weight.

Japanese Unexamined Patent Publication No. 2009-143997 Japanese Unexamined Patent Publication No. 2013-139557 Japanese Unexamined Patent Publication No. 2014-144998

An object of the present invention is to provide a method for producing a cellulose mixture capable of obtaining a highly water-soluble cellulose derivative with a high selectivity when used as a raw material for producing a cellulose derivative.

The present inventors have found that the above problems can be solved by mixing cellulose with a quaternary ammonium hydroxide and a predetermined solvent.
The present invention relates to the following.
[1] A method for producing a cellulose mixture, which comprises a step of mixing a raw material cellulose with a quaternary ammonium hydroxide and a solvent. The solvent contains an organic solvent, and the quaternary ammonium hydroxide and a solvent are used. A method for producing a cellulose mixture, wherein the water content is less than 50% by mass in a total amount of 100% by mass.
[2] A method for producing a cellulose derivative, which comprises a step of obtaining a cellulose mixture by the method according to the above [1] and a step of mixing and reacting the cellulose mixture with a reactant.
[3] A method for producing regenerated cellulose, which comprises a step of obtaining a cellulose mixture by the method according to the above [1], and a step of mixing the cellulose mixture with a poor solvent for cellulose to reprecipitate cellulose.

When the cellulose mixture obtained by the production method of the present invention is used as a raw material for producing a cellulose derivative, a highly water-soluble cellulose derivative can be obtained with a high selectivity. The cellulose mixture is also suitably used for producing regenerated cellulose.

6 is a wide-angle X-ray diffraction pattern of the raw material pulp used for producing the regenerated cellulose of Example 8 and the obtained regenerated cellulose.

[Method for producing cellulose mixture]
The method for producing a cellulose mixture of the present invention (hereinafter, also referred to as "the method for producing the present invention") includes a step of mixing a raw material cellulose with a quaternary ammonium hydroxide and a solvent, and the solvent is an organic solvent. The content of water is less than 50% by mass in a total amount of 100% by mass of the quaternary ammonium hydroxide and the solvent. In the present invention, the cellulose mixture may be a mixture containing cellulose, a quaternary ammonium hydroxide and a solvent, and for example, (1) a mixture in a solid state containing cellulose, a quaternary ammonium hydroxide and a solvent. Either (2) a wet or suspended mixture containing cellulose, a quaternary ammonium hydroxide and a solvent, or (3) a mixture in which cellulose is dissolved in a quaternary ammonium hydroxide and a solvent. Also includes aspects. The "mixture in a solid state" in (1) means a mixture in a state other than (2) and (3).

When the cellulose mixture obtained by the production method of the present invention is used as a raw material for producing a cellulose derivative, it has an effect that the cellulose derivative can be obtained with a high selectivity. The reason for this is not clear, but it can be considered as follows.
Since cellulose has high crystallinity, it has low solubility in solvents such as water and organic solvents, and has low reaction activity with various reactants used for producing cellulose derivatives. The quaternary ammonium hydroxide can activate cellulose like other alkaline compounds, acts as a reaction catalyst between cellulose and a reactant, and the solvent containing the quaternary ammonium hydroxide is cellulose. It also serves as a good solvent for.
When a quaternary ammonium hydroxide and a solvent containing an organic solvent are used in combination, the quaternary ammonium hydroxide diffuses uniformly into the raw material cellulose, so that the cellulose is uniformly activated. Further, when the content of water in 100% by mass of the total amount of the quaternary ammonium hydroxide and the solvent is less than 50% by mass, in addition to the above effects, hydrolysis of the alkylene oxide as a reactant is suppressed. You can also do it.
Therefore, according to the method of the present invention, cellulose can be activated even if the amount of quaternary ammonium hydroxide used is small, and the reaction selectivity and reaction uniformity of a reactant such as alkylene oxide are also improved. , It is considered that a highly water-soluble cellulose derivative can be obtained with a high selectivity.
In addition, the crystallinity of cellulose can be reduced by bringing a mixed solvent of a quaternary ammonium hydroxide and a solvent containing an organic solvent into contact with cellulose. Therefore, the method of the present invention can be used to produce regenerated cellulose. A suitable cellulose mixture can be easily prepared.

<Raw material cellulose>
The raw material cellulose used in the production method of the present invention includes chemically pure cellulose, various wood chips, pruned branches of various trees, thinned wood, branch wood, construction waste, factory waste, and other wood; wood. Pulps such as wood pulp produced from, cotton linter pulp obtained from fibers around cotton seeds; papers such as newspapers, cardboards, magazines, and fine papers; plant stems and leaves such as rice straw and corn stalks. Various cellulose-containing raw materials such as paddy husks, palm husks, coconut husks and other plant husks can be used. Among these, woods such as various wood chips, pruned branches of various trees, thinned wood, branch wood, construction waste, factory waste, etc. from the viewpoint of cellulose purity in raw materials, degree of cellulose polymerization, and availability. Pulps such as wood pulp produced from wood and cotton linter pulp obtained from the fibers around cotton seeds are preferred. In the present invention, chemically pure cellulose or a cellulose-containing raw material used as a raw material is collectively referred to as "raw material cellulose".
The average degree of polymerization of cellulose in the raw material cellulose is not particularly limited, but from the viewpoint of performance when the obtained cellulose derivative is used for various purposes, it is preferably 100 or more, more preferably 200 or more, still more preferably 500 or more. It is even more preferably 1,000 or more, and from the viewpoint of availability, the average degree of polymerization is preferably 12,000 or less, more preferably 10,000 or less, still more preferably 5,000 or less, and even more preferably 5,000 or less. It is 2,500 or less.
The average degree of polymerization of the raw material cellulose means the average degree of polymerization of viscosity measured by the copper-ammonia method or the like described in Examples.

The shape of the raw material cellulose is not particularly limited, but from the viewpoint of operation, it is preferably in the form of a sheet, pellet, chip, cotton or powder, more preferably in the form of chip, cotton or powder, and in operation. From the viewpoint of improving the reactivity with the reactant used for producing the cellulose derivative, the powder form is more preferable. The chip-shaped raw material cellulose can be obtained, for example, by cutting the raw material cellulose. The powdered raw material cellulose can be obtained, for example, by cutting the raw material cellulose as necessary, drying the raw material cellulose, and then pulverizing the raw material cellulose. In the pulverization treatment, the raw material cellulose can be pulverized and the crystallinity can be reduced, so that the reactivity can be further improved. Hereinafter, the cutting treatment, the drying treatment, and the crushing treatment will be described.

(Cut processing)
Depending on the type and shape of the raw material cellulose, it is preferable to perform a cutting treatment as a pretreatment. The method for cutting the raw material cellulose can be appropriately selected depending on the type and shape of the raw material cellulose, and examples thereof include a method using one or more cutting machines selected from a shredder, a slitter cutter and a rotary cutter.
When a sheet-shaped raw material cellulose is used, it is preferable to use a shredder or a slitter cutter as a cutting machine, and it is more preferable to use a slitter cutter from the viewpoint of improving productivity.
A slitter cutter is a cutting machine that cuts vertically along the longitudinal direction of a sheet with a roll cutter to form an elongated strip, and then cuts shortly in the width direction of the sheet with a fixed blade and a rotary blade. By using a slitter cutter, the shape of the raw material cellulose can be diced. As the slitter cutter, a cutting machine (super cutter) manufactured by Ogino Seiki Seisakusho Co., Ltd., a sheet pelletizer manufactured by Horai Co., Ltd., etc. can be preferably used. Can be cut.

When cutting wood such as thinned wood, pruned branch wood, construction waste wood, or raw material cellulose other than sheet-shaped wood, it is preferable to use a rotary cutter. The rotary cutter is composed of a rotary blade and a screen, and by using the rotary cutter, raw material cellulose cut to a size equal to or smaller than the opening of the screen by the rotary blade can be easily obtained. If necessary, a fixed blade may be provided, and cutting may be performed by a rotary blade and a fixed blade.
When using a rotary cutter, the size of the cut product obtained can be controlled by changing the opening of the screen.

The size of the raw material cellulose obtained after the cutting treatment is preferably 1 mm square or more, more preferably 2 mm square or more from the viewpoint of improving productivity, and from the viewpoint of reducing the load required for crushing in the subsequent crushing treatment. From the viewpoint of efficiently and easily performing the drying treatment described later, the size is preferably 70 mm square or less, more preferably 50 mm square or less.

(Drying process)
In general, commercially available pulps, papers used as biomass resources, woods, plant stems / leaves, plant shells and other raw material celluloses contain more than 5% by mass of water, and usually 5 to 30%. It contains about mass% of water. Therefore, it is preferable to adjust the water content by drying the raw material cellulose, preferably the raw material cellulose obtained after the cutting treatment, from the viewpoint of obtaining the effect of the present invention. Further, the smaller the water content of the raw material cellulose used for the pulverization treatment, the more efficiently the pulverization and the low crystallization proceed.

The temperature in the drying treatment is preferably 50 ° C. or higher, more preferably 100 ° C. or higher, still more preferably 130 ° C. or higher from the viewpoint of efficient drying, and preferably 250 ° C. or lower, more preferably 250 ° C. or lower from the viewpoint of quality assurance. Is 200 ° C. or lower, more preferably 170 ° C. or lower. The drying treatment time is preferably 0.01 hours or more, more preferably 0.1 hours or more, still more preferably 0.5 hours or more from the viewpoint of reducing the amount of water, and is preferable from the viewpoint of efficient drying. Is 2 hours or less, more preferably 1.5 hours or less.
If necessary, the drying treatment may be carried out under reduced pressure, and from the viewpoint of efficient drying, the absolute pressure is preferably 1 kPa or more, more preferably 50 kPa or more, still more preferably 100 kPa or more, and preferably 100 kPa or more. It is 120 kPa or less, more preferably 105 kPa or less.
As the drying method, a known drying means may be appropriately selected. For example, the method described in "Introduction to Powder Engineering" (edited by Japan Powder Industry Technology Association, published in 1995 by Powder Engineering Information Center) is described on page 176. Can be mentioned. Examples of the drying means include a hot air heat receiving drying method, a conduction heat receiving drying method, a dehumidifying air drying method, a cold air drying method, a microwave drying method, an infrared drying method, a sun drying method, a vacuum drying method, and a freeze drying method. ..
These drying methods may be used alone or in combination of two or more, and the conduction heat receiving drying method is preferable from the viewpoint of efficient drying. The drying treatment can be either batch treatment or continuous treatment, but continuous treatment is desirable from the viewpoint of improving productivity.

As the continuous dryer, a conduction heat receiving type horizontal stirring dryer is preferable from the viewpoint of heat transfer efficiency. Further, a biaxial horizontal stirring dryer is preferable from the viewpoint that fine powder is less likely to be generated and the stability of continuous discharge is improved. As the 2-axis horizontal stirring dryer, a 2-axis paddle dryer manufactured by Nara Machinery Co., Ltd. can be preferably used.

The lower limit of the water content of the raw material cellulose after the drying treatment is 0% by mass with respect to the raw material cellulose, but from the viewpoint of improving productivity, the water content is preferably 0.1% by mass or more, more preferably 0.1% by mass or more. It is 0.5% by mass or more, more preferably 1.0% by mass or more. Further, from the viewpoint of efficiently pulverizing and lowering the crystallization of the raw material cellulose in the pulverization treatment, from the viewpoint of facilitating the adjustment of the water content in the cellulose mixture, and from the viewpoint of improving the water solubility of the obtained cellulose derivative, the moisture concerned The amount is preferably 2.5% by mass or less, more preferably 2.3% by mass or less, still more preferably 2.1% by mass or less, still more preferably 2.0% by mass or less, still more preferably 1. It is 5% by mass or less.
Specifically, the water content can be measured by the method described in Examples.

(Crushing)
The crusher used in the pulverization treatment is not particularly limited as long as it is an apparatus capable of pulverizing the raw material cellulose.
Specific examples of the crusher include a high-pressure compression roll mill, a roll mill such as a roll rotation mill, a ring roller mill, a vertical roller mill such as a roller race mill or a ball race mill, a rolling ball mill, a vibrating ball mill, a vibrating rod mill, and a vibrating tube. Container-driven medium mills such as mills, planetary ball mills or centrifugal fluidization mills, tower crushers, stirring tank mills, medium stirring mills such as distribution tank mills, compact shear mills such as high-speed centrifugal roller mills and ong mills, Examples include mortars, millstones, mass colloiders, fret mills, edge runner mills, knife mills, cutter mills, and the like.
Among these, from the viewpoint of improving the pulverization efficiency and low crystallization efficiency of the raw material cellulose, a container-driven medium mill or a medium stirring type mill is preferable, a container-driven medium mill is more preferable, and a vibration ball mill, a vibration rod mill or a vibration. A vibration mill such as a tube mill is more preferable, and a vibration rod mill is even more preferable. The crushing method may be either a batch type or a continuous type.
The material of the apparatus and the material of the medium used for the crushing treatment are not particularly limited, and examples thereof include iron, stainless steel, alumina, zirconia, silicon carbide, silicon carbide, glass, etc., but from the viewpoint of crushing efficiency of the raw material cellulose, Iron, stainless steel, zirconia, silicon carbide, and silicon nitride are preferable, and iron or stainless steel is particularly preferable from the viewpoint of industrial use.

From the viewpoint of improving the pulverization efficiency and low crystallization efficiency of the raw material cellulose, when the device used is a vibration mill and the medium is a rod, the outer diameter of the rod is preferably 0.1 mm or more from the viewpoint of pulverization efficiency. , More preferably 0.5 mm or more, and from the same viewpoint, preferably 100 mm or less, more preferably 50 mm or less.
The rod filling rate varies depending on the model of the vibration mill, but is preferably 10% by volume or more, more preferably 10% by volume or more, based on the volume of the crushing container, from the viewpoint of improving the crushing efficiency and productivity of the raw material cellulose. Is 15% by volume or more, more preferably 50% by volume or more, 60% by volume or more, and preferably 97% by volume or less, more preferably 90% by volume or less, still more preferably 80% by volume or less, still more preferably 70. It is less than or equal to the volume.
When the filling rate is within this range, the contact frequency between the raw material cellulose and the rod can be improved, and the pulverization efficiency can be improved without hindering the movement of the medium. Here, the filling rate means the volume of the rod with respect to the volume of the stirring portion of the vibrating mill.

The crusher used for the crushing treatment may be one type or a combination of two or more types. Further, from the viewpoint of improving the pulverization efficiency and low crystallization efficiency of the raw material cellulose, the pulverization treatment may be performed in a plurality of stages. When the pulverization treatment is performed in a plurality of stages, for example, a method of coarsely pulverizing the raw material cellulose which has been subjected to the cutting treatment and the drying treatment and then performing the particle size reduction treatment can be mentioned. In the particle size reduction treatment, an operation of removing coarse powder using a sieve may be used in combination.

As the pulverizer used in the particle size reduction treatment, a high-speed rotary pulverizer is preferable. The high-speed rotary pulverizer is a device that pulverizes coarsely pulverized cellulose loaded in a pulverization cylinder by impact and shearing by rotating a hammer, a blade, a pin, etc. at high speed.
As a high-speed rotary pulverizer used for the particle size reduction treatment, the high-speed rotary mill and classification described on page 843 of "Revised Sixth Edition Chemical Engineering Handbook" (edited by the Society of Chemical Engineers of Japan, Maruzen Co., Ltd., published in 1999). Examples include those classified as a built-in high-speed rotary mill. Among these high-speed rotary mills and high-speed rotary mills with a built-in classifier, any one selected from the group consisting of a hammer mill, a disintegrator, a turbo type mill, and an annual type mill from the viewpoint of reducing the particle size of coarsely pulverized cellulose. Seeds are preferred.
The hammer mill is an atomizer or sample mill manufactured by Dalton Corporation, the disintegrator is a free crusher manufactured by Nara Kikai Seisakusho Co., Ltd., the turbo type mill is a turbo mill manufactured by Turbo Kogyo Co., Ltd., and the annual type mill is Earth Co., Ltd. Each of Technica's Cryptron series can be preferably used.

The temperature during the pulverization treatment is not particularly limited, but is preferably −20 ° C. or higher, more preferably −10 ° C. or higher, still more preferably 0 ° C. or higher, preferably 0 ° C. or higher, from the viewpoint of suppressing the decomposition and operation cost of cellulose. It is 200 ° C. or lower, more preferably 150 ° C. or lower, still more preferably 100 ° C. or lower. If a temperature rise is observed due to heat generated during the treatment, operations such as cooling can be performed.
The time of the pulverization treatment may be appropriately adjusted so that the raw material cellulose is pulverized. The crushing treatment time varies depending on the crusher used, the amount of energy used, and the like, but from the viewpoint of sufficiently pulverizing the raw material cellulose, it is preferably 0.01 hours or more, more preferably 0.05 hours or more, and is produced. From the viewpoint of improving the property, it is preferably 20 hours or less, more preferably 10 hours or less, still more preferably 5 hours or less.

By the above pulverization treatment, powdering and low crystallization of the raw material cellulose proceed, and a powdered raw material cellulose suitable for use in the production method of the present invention can be obtained.
The crystallinity of the powdered raw material cellulose obtained after the pulverization treatment is preferably 95% or less, more preferably 50% or less, from the viewpoint of solubility and improvement of reactivity with a reactant described later. More preferably, it is 30% or less, and preferably 0% or more. The smaller the crystallinity of cellulose, the less likely it is that there will be a difference in the reaction rate between the crystalline portion and the amorphous portion, and the reaction will proceed more uniformly.
In the present invention, the crystallinity of cellulose indicates the crystallinity derived from the I-type crystal structure of the raw material cellulose, and is calculated from the result of X-ray crystal diffraction measurement by the following calculation formula (1).
Crystallinity (%) = [(I _22.6 −I _18.5 ) / I _22.6 ] × 100 (1)
[In the formula, I _22.6 shows the diffraction intensity of the lattice plane (002 plane) (diffraction angle 2θ = 22.6 °) of the cellulose I type crystal in X-ray diffraction, and I _18.5 is the amorphous part (diffraction angle 2θ =). It shows a diffraction intensity of 18.5 °). ]

The average degree of polymerization of the powdered raw material cellulose obtained after the pulverization treatment is preferably 200 or more, more preferably 500 or more, from the viewpoint of performance when the obtained cellulose derivative is used for various purposes. Further, from the viewpoint of availability of the raw material cellulose, the average degree of polymerization is preferably 3,000 or less, more preferably 2,000 or less, and further preferably 1,000 or less.

The water content in the powdered raw material cellulose obtained after the pulverization treatment is 0% by mass or more, but from the viewpoint of improving productivity and availability, it is preferably 0.1% by mass or more, more preferably. It is 0.5% by mass or more, more preferably 1.0% by mass or more. Further, from the viewpoint of reducing the water content in the cellulose mixture, the water content is preferably 2.5% by mass or less, more preferably 2.3% by mass or less, still more preferably 2.1% by mass or less. It is more preferably 2.0% by mass or less, and even more preferably 1.5% by mass or less.

The median diameter of the powdered raw material cellulose obtained after the pulverization treatment is preferably 10 μm or more, more preferably 20 μm, from the viewpoint of reaction uniformity with the reactant and improving the productivity of the powdered raw material cellulose. As described above, it is more preferably 30 μm or more, and from the viewpoint of solubility, it is preferably 1000 μm or less, more preferably 500 μm or less, still more preferably 200 μm or less.

<Quaternary ammonium hydroxide>
Examples of the quaternary ammonium hydroxide used in the present invention include ammonium hydroxide having four substituted or unsubstituted hydrocarbon groups. For example, as the quaternary ammonium hydroxide, a compound represented by the following general formula (1) is preferable.

式（１）中、Ｒ^１〜Ｒ^４はそれぞれ独立に、炭素数１以上２４以下の、置換又は非置換の炭化水素基である。
当該「置換又は非置換の炭化水素基」としては、アルキル基、ヒドロキシアルキル基、アリール基、ヒドロキシアリール基、及びアラルキル基からなる群から選ばれる１種以上が好ましく、アルキル基及びアラルキル基からなる群から選ばれる１種以上がより好ましく、アルキル基がさらに好ましい。

In the formula (1), R ^{1 to} R ⁴ are independently substituted or unsubstituted hydrocarbon groups having 1 or more and 24 or less carbon atoms.
The "substituted or unsubstituted hydrocarbon group" is preferably at least one selected from the group consisting of an alkyl group, a hydroxyalkyl group, an aryl group, a hydroxyaryl group, and an aralkyl group, and is composed of an alkyl group and an aralkyl group. One or more selected from the group is more preferable, and an alkyl group is further preferable.

The alkyl group may be either a straight chain or a branched chain. The alkyl group of the linear or branched chain has 1 or more carbon atoms, and is preferably 2 or more, more preferably 3 or more, from the viewpoint of reducing the crystallinity of cellulose. From the viewpoint of solvent solubility, the alkyl group of the linear or branched chain preferably has 24 or less carbon atoms, more preferably 20 or less, still more preferably 18 or less, still more preferably 12 or less, and even more preferably 10. Below, it is even more preferably 8 or less, and even more preferably 6 or less. Further, among the linear or branched alkyl groups, a linear alkyl group is preferable.
Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a t-butyl group, a pentyl group, an isopentyl group, a neopentyl group, a hexyl group, a heptyl group, an octyl group and an isooctyl group. 2-Ethylhexyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadesyl group, icosyl group, docosyl group, henicosyl group, docosyl group, Examples thereof include a tricosyl group and a tetracosyl group. Among these, at least one selected from the group consisting of a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group is preferable, and from the group consisting of an ethyl group, a propyl group, a butyl group, and a hexyl group. One or more selected are more preferable, and a butyl group is further preferable.

The hydroxyalkyl group has 1 or more carbon atoms, and is preferably 2 or more, more preferably 3 or more, from the viewpoint of reducing the crystallinity of cellulose. From the viewpoint of solvent solubility, the hydroxyalkyl group preferably has 24 or less carbon atoms, more preferably 20 or less, still more preferably 18 or less, still more preferably 12 or less, still more preferably 10 or less, and even more preferably. Is 8 or less, more preferably 6 or less.
Examples of the hydroxyalkyl group include 2-hydroxyethyl group, 2-hydroxypropyl group, 3-hydroxypropyl group, 4-hydroxybutyl group, hydroxypentyl group, hydroxyhexyl group, hydroxyheptyl group, hydroxyoctyl group and hydroxynonyl group. , Hydroxydecyl group, hydroxyundecyl group, hydroxydodecyl group, hydroxytridecyl group, hydroxytetradecyl group, hydroxypentadecyl group, hydroxyhexadecyl group, hydroxyheptadecyl group, hydroxyoctadecyl group, hydroxynonadecil group, hydroxyico Examples thereof include a syl group, a hydroxydocosyl group, a hydroxyhenicosyl group, a hydroxydocosyl group, a hydroxytricosyl group, and a hydroxytetracosyl group.

The aryl group and the hydroxyaryl group have 6 or more carbon atoms, and from the viewpoint of solvent solubility, the number of carbon atoms is preferably 24 or less, more preferably 20 or less, still more preferably 18 or less, still more preferably 16 or less. It is even more preferably 12 or less, and even more preferably 8 or less. Examples of the aryl group include a phenyl group, a tolyl group, a xsilyl group, an ethylphenyl group, a diethylphenyl group, a propylphenyl group, a butylphenyl group, a naphthyl group, a phenanthryl group and the like. Among these, a phenyl group is preferable. Examples of the hydroxyaryl group include a hydroxyphenyl group, a cresyl group, and a hydroxynaphthyl group.
The aralkyl group has 7 or more carbon atoms, and from the viewpoint of solvent solubility, it preferably has 24 or less carbon atoms, more preferably 19 or less, still more preferably 17 or less, still more preferably 13 or less, and even more preferably. Is 9 or less. Examples of the aralkyl group include a benzyl group, a methylbenzyl group, a 1-phenylethyl group, a 2-phenylethyl group, a 3-phenylpropyl group, a 4-phenylbutyl group, a naphthylmethyl group and the like. Among these, a benzyl group is preferable.

R ^{1 to} R ⁴ may be the same or different from each other. Among the above, R ^{1 to} R ⁴ are independently linear or branched alkyl groups having 1 to 12 carbon atoms, aryl groups having 6 to 18 carbon atoms, and aralkyl groups having 7 to 19 carbon atoms. One or more selected from the group consisting of 1 or more is preferable, and it is composed of a linear or branched alkyl group having 1 or more and 8 or less carbon atoms, an aryl group having 6 or more and 12 or less carbon atoms, and an aralkyl group having 7 or more and 13 or less carbon atoms. One or more selected from the group is more preferable, and one selected from the group consisting of a linear alkyl group having 1 or more and 6 or less carbon atoms, an aryl group having 6 or more and 8 or less carbon atoms, and an aralkyl group having 7 or more and 9 or less carbon atoms. More than one kind is more preferable, and one or more kinds selected from the group consisting of a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a phenyl group, and a benzyl group are even more preferable. More preferably, one or more selected from the group consisting of a propyl group, a butyl group, and a benzyl group.
From the viewpoint of solvent solubility, ^{it is preferable that two or more of R 1 to} R ⁴ are linear alkyl groups having 1 to 6 carbon atoms, and 3 or more are linear alkyl groups having 1 to 6 carbon atoms. It is more preferable that it is an alkyl group, and it is further preferable that all four are linear alkyl groups having 1 or more and 6 or less carbon atoms. The linear alkyl group preferably has 2 or more carbon atoms, and more preferably 3 or more carbon atoms.

^{Further, the total number of carbon atoms of the four substituents (R 1 to} R 4 in the general formula (1)) contained in the quaternary ammonium hydroxide is 4 or more, preferably 8 or more, more preferably 12 or more. is there. From the viewpoint of solvent solubility, the number of carbon atoms is preferably 48 or less, more preferably 40 or less, still more preferably 32 or less, still more preferably 24 or less, still more preferably 22 or less, still more preferably 18 or less. Is.

Specific examples of the quaternary ammonium hydroxide are tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrabutylammonium hydroxide (TBAH), tetrahexylammonium hydroxide (THAH), and trimethylpentyl. Examples thereof include ammonium hydroxide, tributylethylammonium hydroxide, benzyltrimethylammonium hydroxide (BTMAH), and benzyltriethylammonium hydroxide. Among these, it consists of tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrabutylammonium hydroxide (TBAH), benzyltrimethylammonium hydroxide (BTMAH), and benzyltriethylammonium hydroxide (BTEAH). One or more selected from the group is preferable, and one or more selected from the group consisting of tetrabutylammonium hydroxide (TBAH), benzyltrimethylammonium hydroxide (BTMAH), and benzyltriethylammonium hydroxide (BTEAH) is more preferable. One or more selected from the group consisting of tetrabutylammonium hydroxide (TBAH) and benzyltriethylammonium hydroxide (BTEAH) is more preferable, and tetrabutylammonium hydroxide (TBAH) is even more preferable.
The quaternary ammonium hydroxide may be used alone or in combination of two or more.

The method for producing the quaternary ammonium hydroxide is not particularly limited, and a known method can be used.
If isolation is difficult during the production of the quaternary ammonium hydroxide, the quaternary ammonium hydroxide may be used in a state containing a solvent described later. From the viewpoint of obtaining the effects of the present invention, the solvent is preferably an organic solvent. The organic solvent is not particularly limited as long as it can dissolve the quaternary ammonium hydroxide, but it is preferably a polar solvent from the viewpoint of suppressing the decomposition of the quaternary ammonium hydroxide, and is protic. Polar solvents are more preferred. As the polar solvent, the same polar solvent as those exemplified in the solvent described later can be used.

<Solvent>
The solvent used in the production method of the present invention contains an organic solvent, and the water content is less than 50% by mass in the total amount of 100% by mass of the quaternary ammonium hydroxide mixed with the raw material cellulose and the solvent. It is characterized by. Since the solvent contains an organic solvent and the water content is reduced, hydrolysis of the alkylene oxide can be suppressed, so that the reaction selectivity is also improved. For example, in the production of a cellulose mixture, when the solvent to be mixed with the raw material cellulose is only water or when the content of water in the solvent mixed with the raw material cellulose is large, the reaction selectivity is lowered.

(Organic solvent)
The organic solvent used in the present invention is not particularly limited, but a polar solvent is preferable from the viewpoint of uniformly diffusing the quaternary ammonium hydroxide in the raw material cellulose and from the viewpoint of affinity with cellulose. Examples of the polar solvent include a protonic polar solvent and an aprotic polar solvent.
Examples of the protonic polar solvent used in the present invention include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, t-butanol, 1-pentanol, 2-pentanol, 2, 2-Dimethyl-1-propanol, hexanol, cyclohexanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, (1-methylethoxy) -2-propanol, 1- (2-butoxyethoxy) -2 -Monohydric alcohols such as propanol, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether; ethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, neopentyl glycol, butanediol, pentanediol, hexanediol , Dihydric alcohols such as cyclohexanediol and polyalkylene glycol; trihydric alcohols such as hexanetriol, octanetriol, decantriol, trimethylolethane, trimethylolpropane, ethyloxyltrimethylolpropane, trimethylolbutane and glycerin; Be done. Among these, a monohydric alcohol is preferable from the viewpoint of solubility of the quaternary ammonium hydroxide, and one or more selected from the group consisting of methanol, ethanol, 1-propanol, and 2-propanol is more preferable.
The aprotonic polar solvent is a polar solvent that does not have active hydrogen such as a hydroxyl group, and is, for example, an amide solvent such as acetonitrile; dimethylsulfoxide; N, N-dimethylformamide, N, N-dimethylacetamide; N-methylpyrrolidone. , Lactones such as γ-butyrolactone; cyclic ethers such as tetrahydrofuran and 1,4-dioxane; ketones such as acetone and methylisobutylketone; halogen-based solvents such as methylene chloride, 1,2-dichloroethane and chloroform; Be done.

The polar solvent may be used alone or in combination of two or more. Among them, from the viewpoint of affinity with cellulose and quaternary ammonium hydroxide, it is more preferable that the organic solvent contains an aprotic polar solvent, and as the aprotic polar solvent, acetonitrile, dimethyl sulfoxide, N, N- It is more preferable to contain one or more selected from the group consisting of dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, and γ-butyrolactone, and more than one selected from the group consisting of acetonitrile and dimethyl sulfoxide. Is even more preferable.
From the viewpoint of removing the aprotic polar solvent from the cellulose derivative or regenerated cellulose which is the final product, a low boiling point aprotic polar solvent is preferable, and acetonitrile is more preferable. On the other hand, from the viewpoint of avoiding volatilization of the aprotic polar solvent in the production process of the cellulose mixture, a high boiling point aprotic polar solvent is preferable, and dimethyl sulfoxide is more preferable.

The content of the aprotic polar solvent in the polar solvent is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 10% by mass or more, from the viewpoint of compatibility with cellulose and quaternary ammonium hydroxide. It is 20% by mass or more, more preferably 30% by mass or more, and even more preferably 50% by mass or more. The upper limit is 100% by mass, preferably 90% by mass or less, and more preferably 85% by mass or less.

In the production method of the present invention, the content of water is less than 50% by mass in the total amount of 100% by mass of the quaternary ammonium hydroxide and the solvent mixed with the raw material cellulose. When the water content is low, the reaction selectivity of the obtained cellulose derivative is improved.
The lower limit of the water content is 0% by mass. From the viewpoint of obtaining the above effects, the water content is preferably 40% by mass or less, more preferably 25% by mass or less, still more preferably 10% by mass or less, still more preferably 7.5% by mass or less, still more. It is preferably 5.0% by mass or less, and even more preferably 2.0% by mass or less.

(amount to use)
The preferable amounts of the quaternary ammonium hydroxide and the solvent to be mixed with the raw material cellulose are as follows.
The ratio of the quaternary ammonium hydroxide to the solvent is not particularly limited. From the viewpoint of improving the activation of cellulose, the viewpoint of the solubility of cellulose, and the viewpoint of improving the water solubility and reaction selectivity of the obtained cellulose derivative, the mass ratio of the quaternary ammonium hydroxide to the solvent (quaternary). The ammonium hydroxide / solvent) is preferably 1/99 to 99/1, more preferably 5/95 to 95/5, even more preferably 10/90 to 90/10, even more preferably 15/85 to 85. / 15, even more preferably 15/85 to 80/20, even more preferably 15/85 to 75/25, even more preferably 20/80 to 70/30, even more preferably 20/80 to 60/40. , More preferably 30/70 to 60/40, and even more preferably 30/70 to 55/45.

Here, in the production of the cellulose derivative described later, it is preferable to react the cellulose with the reactant in a solid phase state from the viewpoint of productivity and economy. Therefore, the cellulose mixture used as a raw material for producing the cellulose derivative is preferably in a solid state.
When producing a cellulose mixture in a solid state, the amount of the quaternary ammonium hydroxide to be mixed with the raw material cellulose is obtained from the viewpoint of activating the cellulose and improving the reaction uniformity and reaction efficiency with the reactant. From the viewpoint of improving the water solubility and reaction selectivity of the cellulose derivative, preferably 0.01 molar equivalent or more with respect to 1 mol of anhydroglucose unit (hereinafter, also referred to as “AGU”) of the cellulose constituting the main chain of the raw material cellulose. , More preferably 0.1 molar equivalent or more, still more preferably 0.2 molar equivalent or more, even more preferably 0.5 molar equivalent or more, and from the viewpoint of economic efficiency, preferably 5.0 molar equivalent or less. It is preferably 3.0 molar equivalents or less, more preferably 2.0 molar equivalents or less, even more preferably 1.5 molar equivalents or less, still more preferably 1.3 molar equivalents or less.
When producing a cellulose mixture in a solid state, the total amount of the quaternary ammonium hydroxide and the solvent is preferably 50% by mass or more, more preferably 70% by mass or more, still more preferably 100, based on the raw material cellulose. It is preferably 800% by mass or less, more preferably 150% by mass or more, still more preferably 200% by mass or more, and preferably 800% by mass or less, more preferably 650% by mass or less, still more preferably 500, from the viewpoint of maintaining a solid state. It is mass% or less, more preferably 400 mass% or less.

On the other hand, when a cellulose solution is produced as a cellulose mixture, the amount of the quaternary ammonium hydroxide used is obtained from the viewpoint of activating the cellulose and improving the reaction uniformity and reaction efficiency with the reactant. From the viewpoint of improving the water solubility and reaction selectivity of the cellulose derivative, preferably 0.01 molar equivalent or more, more preferably 0.1 molar equivalent or more, still more preferably 0.2 molar equivalent or more, relative to 1 mol of AGU of cellulose. , More preferably 0.5 molar equivalents or more, even more preferably 0.7 molar equivalents or more. The upper limit of the amount of the quaternary ammonium hydroxide used and the total amount of the quaternary ammonium hydroxide and the solvent are not particularly limited as long as the amount of the quaternary ammonium hydroxide is dissolved, and the desired concentration of the cellulose solution is not limited. It can be selected as appropriate according to.
The cellulose concentration in the cellulose solution is selected from, for example, 0.01% by mass or more and 25% by mass or less.

The content of water in the cellulose mixture is preferably 50% by mass or less, more preferably 30% by mass or less, still more preferably 10% by mass or less, still more preferably 5.0% by mass, from the viewpoint of obtaining the effects of the present invention. % Or less, more preferably 2.5% by mass or less, still more preferably 1.0% by mass or less. The lower limit of the water content in the cellulose mixture is 0% by mass.

In the production method of the present invention, the mixing order of the raw material cellulose, the quaternary ammonium hydroxide and the solvent is not particularly limited. For example, (i) a method of mixing raw material cellulose and quaternary ammonium hydroxide and then adding a solvent to mix, (ii) a method of mixing raw material cellulose with a mixture of quaternary ammonium hydroxide and solvent. Examples thereof include a method of adding and mixing, a method of (iii) mixing a raw material cellulose and a solvent, and then adding and mixing a quaternary ammonium hydroxide.
The quaternary ammonium hydroxide may be added and mixed in a state containing a part of the solvent. For example, in the method (i), a mixed solution containing a quaternary ammonium hydroxide and a part of the solvent is prepared, mixed with the raw material cellulose, and then the rest of the solvent is added and mixed. In the method (iii), a mixed solution containing a quaternary ammonium hydroxide and a part of the solvent is prepared, the raw material cellulose and the rest of the solvent are mixed, and then the mixed solution is added and mixed. To do.
When producing a cellulose mixture in a solid state, the method (iii) is preferable from the viewpoint of uniformly mixing each component. Above all, it is preferable that the "residue of the solvent" is an aprotic polar solvent. That is, it is a method in which the raw material cellulose and the aprotic polar solvent are mixed, and then the mixed solution is added and mixed.
The mixing method of each component is not particularly limited as long as the raw material cellulose, the quaternary ammonium hydroxide, and the solvent can be uniformly mixed, and for example, a known mechanical stirrer or the like can be used.

The temperature at the time of mixing each component is not particularly limited, but is preferably 80 ° C. or lower, more preferably 60 ° C. or lower, still more preferably 40 ° C. or lower, from the viewpoint of avoiding decomposition or volatilization of each component in the cellulose mixture. Further, from the viewpoint of economy and the solubility of the raw material cellulose when the cellulose mixture is a cellulose solution, the temperature is preferably 10 ° C. or higher, more preferably 15 ° C. or higher.
The mixing time of each component is also not particularly limited, but from the viewpoint of uniform mixing, it is preferably 2 minutes or more, more preferably 5 minutes or more, and from the viewpoint of productivity, preferably 72 hours or less, more preferably 48. It's less than an hour.
The cellulose mixture obtained by the method of the present invention is suitably used as a raw material for producing a cellulose derivative or a raw material for producing regenerated cellulose.

[Method for producing cellulose derivatives]
The method for producing a cellulose derivative of the present invention includes a step of obtaining a cellulose mixture by the above method and a step of mixing and reacting the cellulose mixture with a reactant. Since the cellulose mixture contains a solvent containing a quaternary ammonium hydroxide and an organic solvent, the reaction activity and the reaction uniformity with the reactant are high. Further, since the quaternary ammonium hydroxide also acts as a reaction catalyst between cellulose and the reactant, the reaction proceeds efficiently.
As the cellulose mixture, any of a solid state, a wet or suspended state, and a solution state can be used, but as described above, from the viewpoint of productivity and economy, the cellulose and the reactant are reacted in a solid state. It is preferable to let it. Therefore, the cellulose mixture used for producing the cellulose derivative is preferably in a solid state.

<Reactant>
The reactant used in the present invention is a compound used for derivatizing cellulose and is a compound capable of reacting with a primary or secondary hydroxyl group of cellulose to introduce a substituent, for example, hydroxyalkyl. Examples thereof include an agent, a glycerol agent, and a cationizing agent.
The method for producing a cellulose derivative of the present invention is preferably used for producing hydroxyalkyl cellulose. Examples of the reactant used for producing hydroxyalkyl cellulose include hydroxyalkylating agents such as alkylene oxide, alkyl glycidyl ether, and alkyl halohydrin ether. Among these, alkylene oxides are preferable from the viewpoint of no salt formation during the reaction and economic efficiency.
Examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, and one or more selected from the group consisting of propylene oxide and butylene oxide are preferable, and propylene oxide is more preferable.
Hereinafter, as an example of the method for producing a cellulose derivative of the present invention, a method for producing hydroxyalkyl cellulose using an alkylene oxide as a reactant will be described.

The amount of the reactant used in the present invention can be appropriately selected according to the desired amount of the substituent into cellulose. When the reactant is an alkylene oxide, it is preferably 0.01 equivalent or more, more preferably 0.10 equivalent or more, and further, with respect to 1 mol of AGU of cellulose, from the viewpoint of improving the water solubility of the obtained hydroxyalkyl cellulose. It is preferably 0.20 equivalent or more. On the other hand, from the viewpoint of improving the viscosity of the aqueous solution of the reaction product and from the viewpoint of economic efficiency, the amount of alkylene oxide used in the present invention is preferably 50 equivalents or less, more preferably 30 equivalents or less, based on 1 mol of AGU of cellulose. It is more preferably 20 equivalents or less, even more preferably 10 equivalents or less, and even more preferably 5.0 equivalents or less.

The method of adding the alkylene oxide to the cellulose mixture is not particularly limited, and either batch addition or divided addition may be used. From the viewpoint of reaction homogeneity and from the viewpoint of avoiding polymerization of the alkylene oxide itself, split addition is preferable. When the reaction is carried out at a temperature equal to or higher than the boiling point of the alkylene oxide, it is preferable to use a reaction device equipped with a reflux tube and gradually drop the alkylene oxide.

In the present invention, the apparatus may be used to mix and react the cellulose mixture with the reactants. Examples of the apparatus include a mixer such as a Ladyge mixer capable of stirring and a mixer such as a so-called kneader used for kneading powders, high-viscosity substances, resins and the like.
The reaction temperature and the reaction temperature can be appropriately selected depending on the type of the reactant and the like. When the reactant is an alkylene oxide, it is preferably 0 ° C. or higher, more preferably 10 ° C. or higher, still more preferably 20 ° C. or higher, still more preferably 40 ° C. or higher, from the viewpoint of improving the reaction rate. Further, from the viewpoint of suppressing decomposition of the raw material, the reaction temperature is preferably 150 ° C. or lower, more preferably 100 ° C. or lower, still more preferably 80 ° C. or lower, still more preferably 60 ° C. or lower.

The reaction time is preferably 0.1 hour or longer, more preferably 1 hour or longer, still more preferably 3 hours or longer, still more preferably 12 hours or longer, still more preferably 12 hours or longer, from the viewpoint of improving the reaction rate and the reaction yield. 24 hours or more. Further, from the viewpoint of suppressing a decrease in the molecular weight of the main chain derived from anhydroglucose of cellulose, the reaction time is preferably 96 hours or less, more preferably 72 hours or less.
The above reaction is preferably carried out in an inert gas atmosphere such as nitrogen, if necessary, from the viewpoint of suppressing the coloring of hydroxyalkyl cellulose and the decrease in the molecular weight of the main chain derived from anhydroglucose.

After completion of the reaction, a step of neutralizing the quaternary ammonium hydroxide using an acidic compound can be performed. As the acidic compound, inorganic acids such as sulfuric acid, hydrochloric acid and phosphoric acid; and organic acids such as acetic acid, lactic acid, citric acid and glycolic acid can be used. From the viewpoint of neutralization efficiency and from the viewpoint of suppressing a decrease in the molecular weight of the main chain derived from anhydroglucose of cellulose, the acidic compound is preferably an organic acid, more preferably a carboxylic acid, and even more preferably acetic acid.

If necessary, the hydroxyalkyl cellulose obtained after completion of the reaction is separated by filtration and purification, or washed with hot water, hydrous isopropanol, hydroacetone solvent, etc. to unreacted alkylene oxide and by-products derived from alkylene oxide. You can also remove things. In addition, as a purification method, general purification methods such as freeze-drying, reprecipitation purification, centrifugation, and membrane purification using a dialysis membrane can be used. Among these purification methods, filtration purification or membrane purification is preferable from the viewpoint of purification efficiency and high purity of the obtained hydroxyalkyl cellulose.

The obtained hydroxyalkyl cellulose can also be dried if necessary. The drying method is not particularly limited, but from the viewpoint of improving the drying efficiency, vacuum drying is preferable, and freeze drying is more preferable.

From the viewpoint of water solubility, the average number of moles of hydroxyalkyl groups added per mole of AGU of cellulose constituting the cellulose main chain is preferably 0.10 or more, more preferably 0.20 or more, still more preferable. Is 0.50 or more, more preferably 0.80 or more. Further, from the viewpoint of the viscosity of the aqueous solution of hydroxyalkyl cellulose and economic efficiency, it is preferably 20 or less, more preferably 10 or less, still more preferably 8.0 or less, still more preferably 5.0 or less.
Specifically, the average number of moles of hydroxyalkyl groups added can be measured by the method described in Examples.

The hydroxyalkyl cellulose can also be further reacted with a cationizing agent to produce a cationized hydroxyalkyl cell roll.
The cellulose derivative obtained by the production method of the present invention is suitable for compounding components, dispersants, modifiers, flocculants and the like of detergent compositions such as shampoos, rinses, treatments and conditioners.

[Manufacturing method of regenerated cellulose]
The method for producing regenerated cellulose of the present invention is characterized by including a step of obtaining a cellulose mixture by the above method and a step of mixing the cellulose mixture with a poor solvent for cellulose to reprecipitate the cellulose. A mixture of cellulose in a solid state or a solution may be used for producing regenerated cellulose, but it is preferable to use a mixture of cellulose in a solid state as the cellulose mixture. When a cellulose mixture in a solid state is used, regenerated cellulose can be prepared with a smaller amount of solvent, which is preferable in terms of productivity and economy. The raw material cellulose contained in the cellulose mixture, the quaternary ammonium hydroxide, the solvent, the amount of these used, and the preferred embodiment are the same as described above.
From the viewpoint of productivity of regenerated cellulose, the cellulose concentration in the cellulose mixture used for producing regenerated cellulose is preferably 0.1% by mass or more, more preferably 1.0% by mass or more, and preferably 50% by mass or less. , More preferably 30% by mass or less.

The poor solvent for cellulose is not particularly limited, and either water or an organic solvent can be used. The poor solvent is preferably a single composition solvent rather than a mixed solvent. This is because the solvent having a single composition has low solubility of cellulose. Further, from the viewpoint of removing the poor solvent after reprecipitation, the poor solvent preferably has a boiling point of less than 100 ° C. at normal pressure.
From the above viewpoint and the miscibility with the cellulose mixture, the poor solvent is preferably water or a polar solvent having a boiling point of less than 100 ° C. at normal pressure. As the polar solvent, alcohols having 1 or more and 4 or less carbon atoms such as methanol, ethanol, 1-propanol, 2-propanol and 1-butanol, or acetone are preferable, and ethanol is more preferable.
When water is used as the poor solvent, the obtained regenerated cellulose becomes type II crystals, and when a polar solvent such as ethanol is used as the poor solvent, the obtained regenerated cellulose becomes amorphous cellulose.

The method of mixing the cellulose mixture and the poor solvent when reprecipitating cellulose is not particularly limited. For example, the reaction vessel is filled with the poor solvent, and the cellulose mixture is added to the poor solvent with stirring as necessary. The method can be mentioned. At that time, when the cellulose mixture is added to the poor solvent and reprecipitated, powdered or granular regenerated cellulose can be obtained. Further, when a cellulose solution is extruded into a poor solvent in a fibrous form and spun, fibrous regenerated cellulose can be obtained.
The temperature at the time of reprecipitation is not particularly limited as long as it is lower than the boiling point of the poor solvent, and is usually in the range of 0 ° C. or higher and 80 ° C. or lower.
The re-precipitated cellulose can be separated into solid and liquid by filtration or the like, and then washed and dried as necessary to be isolated as regenerated cellulose. The obtained regenerated cellulose is useful as a raw material for producing a cellulose derivative and as a regenerated cellulose fiber.

式（１）中、Ｒ^１〜Ｒ^４はそれぞれ独立に、炭素数１以上２４以下の、置換又は非置換の炭化水素基であり、好ましくは炭素数１以上２４以下の、アルキル基、ヒドロキシアルキル基、アリール基、ヒドロキシアリール基、及びアラルキル基からなる群から選ばれる１種以上、より好ましくは、炭素数１以上１２以下の直鎖又は分岐鎖のアルキル基、炭素数６以上１８以下のアリール基、及び炭素数７以上１９以下のアラルキル基からなる群から選ばれる１種以上、さらに好ましくは炭素数１以上８以下の直鎖又は分岐鎖のアルキル基、炭素数６以上１２以下のアリール基、及び炭素数７以上１３以下のアラルキル基からなる群から選ばれる１種以上、よりさらに好ましくは炭素数１以上６以下の直鎖アルキル基、炭素数６以上８以下のアリール基、及び炭素数７以上９以下のアラルキル基からなる群から選ばれる１種以上、よりさらに好ましくはメチル基、エチル基、プロピル基、ブチル基、ペンチル基、ヘキシル基、フェニル基、及びベンジル基からなる群から選ばれる１種以上、よりさらに好ましくはメチル基、エチル基、プロピル基、ブチル基、及びベンジル基からなる群から選ばれる１種以上である。Ｒ^１〜Ｒ^４は互いに同一でもよく、異なっていてもよい。 Regarding the above-described embodiments, the present invention discloses the following methods for producing a cellulose mixture, a method for producing a cellulose derivative, a method for producing regenerated cellulose, a cellulose mixture, and its use.
<1>
A method for producing a cellulose mixture comprising a step of mixing a raw material cellulose with a quaternary ammonium hydroxide and a solvent, wherein the solvent contains an organic solvent and the total amount of the quaternary ammonium hydroxide and the solvent. The water content in 100% by mass is less than 50% by mass, preferably 40% by mass or less, more preferably 25% by mass or less, still more preferably 10% by mass or less, still more preferably 7.5% by mass or less, and more. A method for producing a cellulose mixture, more preferably 5.0% by mass or less, still more preferably 2.0% by mass or less.
<2>
The method for producing a cellulose mixture according to <1> above, wherein the organic solvent is a polar solvent, preferably containing an aprotic polar solvent.
<3>
The aprotic polar solvent is one or more selected from the group consisting of acetonitrile, dimethyl sulfoxide, N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, and γ-butyrolactone, preferably acetonitrile and dimethyl. The method for producing a cellulose mixture according to <2> above, which is one or more selected from the group consisting of sulfoxide.
<4>
The content of water in the cellulose mixture is preferably 50% by mass or less, more preferably 30% by mass or less, still more preferably 10% by mass or less, still more preferably 5.0% by mass, based on the cellulose in the raw material cellulose. % Or less, more preferably 2.5% by mass or less, still more preferably 1.0% by mass or less, according to any one of <1> to <3> above.
<5>
The quaternary ammonium hydroxide is an ammonium hydroxide having four substituted or unsubstituted hydrocarbon groups, and is preferably a compound represented by the following general formula (1). The method for producing a cellulose mixture according to any one of 4>.

In the formula (1), R ^{1 to} R ⁴ are independently substituted or unsubstituted hydrocarbon groups having 1 to 24 carbon atoms, preferably an alkyl group having 1 to 24 carbon atoms, and a hydroxyalkyl group. One or more selected from the group consisting of a group, an aryl group, a hydroxyaryl group, and an aralkyl group, more preferably a linear or branched alkyl group having 1 or more and 12 or less carbon atoms, and an aryl having 6 or more and 18 or less carbon atoms. One or more selected from the group consisting of a group and an aralkyl group having 7 or more and 19 or less carbon atoms, more preferably a linear or branched alkyl group having 1 or more and 8 or less carbon atoms, and an aryl group having 6 or more and 12 or less carbon atoms. , And one or more selected from the group consisting of aralkyl groups having 7 or more and 13 or less carbon atoms, more preferably a linear alkyl group having 1 or more and 6 or less carbon atoms, an aryl group having 6 or more and 8 or less carbon atoms, and a carbon number of carbon atoms. One or more selected from the group consisting of 7 or more and 9 or less aralkyl groups, more preferably selected from the group consisting of methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, phenyl group, and benzyl group. One or more, more preferably one or more selected from the group consisting of a methyl group, an ethyl group, a propyl group, a butyl group, and a benzyl group. R ^{1 to} R ⁴ may be the same or different from each other.

<6>
^{The total number of carbon atoms of R 1 to} R ⁴ in the general formula (1) is 4 or more, preferably 8 or more, more preferably 12 or more, and 48 or less, preferably 40 or less, more preferably 32 or less, still more preferable. Is 24 or less, more preferably 22 or less, still more preferably 18 or less, the method for producing a cellulose mixture according to <5> above.
<7>
The mass ratio of the quaternary ammonium hydroxide to the solvent is 1/99 to 99/1, preferably 5/95 to 95/5, more preferably 10/90 to 90/10, still more preferably 15 /. 85-85 / 15, even more preferably 15/85-80/20, even more preferably 15/85-75/25, even more preferably 20/80-70/30, even more preferably 20/80- Production of the cellulose mixture according to any one of <1> to <6> above, which is 60/40, more preferably 30/70 to 60/40, and even more preferably 30/70 to 55/45. Method.
<8>
The content of the aprotonic polar solvent in the polar solvent is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 20% by mass or more, still more preferably 30% by mass or more, still more preferably. Is 50% by mass or more, 100% by mass or less, preferably 90% by mass or less, more preferably 85% by mass or less, according to any one of <2> to <7> above. Method.
<9>
The quaternary ammonium hydroxide is tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrabutylammonium hydroxide (TBAH), benzyltrimethylammonium hydroxide (BTMAH), and benzyltriethylammonium hydroxide. One or more selected from the group consisting of (BTEAH), preferably one selected from the group consisting of tetrabutylammonium hydroxide (TBAH), benzyltrimethylammonium hydroxide (BTMAH), and benzyltriethylammonium hydroxide (BTEAH). The above <1>, more preferably one or more selected from the group consisting of tetrabutylammonium hydroxide (TBAH) and benzyltriethylammonium hydroxide (BTEAH), and even more preferably tetrabutylammonium hydroxide (TBAH). The method for producing a cellulose mixture according to any one of <8>.
<10>
The method for producing a cellulose mixture according to any one of <1> to <9> above, wherein the cellulose mixture is in a solid state.

<11>
The amount of the quaternary ammonium hydroxide mixed with the raw material cellulose is preferably 0.01 molar equivalent or more, more preferably 0, relative to 1 mol of anhydroglucose units of the cellulose constituting the main chain of the raw material cellulose. .1 molar equivalent or more, more preferably 0.2 molar equivalent or more, still more preferably 0.5 molar equivalent or more, preferably 5.0 molar equivalent or less, more preferably 3.0 molar equivalent or less, still more preferable. The method for producing a cellulose mixture according to <10> above, wherein is 2.0 molar equivalents or less, more preferably 1.5 molar equivalents or less, still more preferably 1.3 molar equivalents or less.
<12>
The total amount of the quaternary ammonium hydroxide and the solvent is preferably 50% by mass or more, more preferably 70% by mass or more, still more preferably 100% by mass or more, still more preferably 150, based on the raw material cellulose. By mass% or more, more preferably 200% by mass or more, preferably 800% by mass or less, more preferably 650% by mass or less, still more preferably 500% by mass or less, still more preferably 400% by mass or less. 10> or <11>. The method for producing a cellulose mixture.
<12>
The method for producing a cellulose mixture according to any one of <1> to <9> above, wherein the cellulose mixture is a cellulose solution.
<13>
The content of water in the cellulose mixture is preferably 50% by mass or less, more preferably 30% by mass or less, still more preferably 10% by mass or less, still more preferably 5.0% by mass or less, still more preferably 2. The method for producing a cellulose mixture according to any one of <1> to <12> above, which is 5.5% by mass or less, more preferably 1.0% by mass or less.
<14>
A method for producing a cellulose derivative, which comprises a step of obtaining a cellulose mixture by the method according to any one of <1> to <13> above, and a step of mixing and reacting the cellulose mixture with a reactant.
<15>
The method for producing a cellulose derivative according to <14> above, wherein the reactant is one or more selected from the group consisting of alkylene oxide, preferably propylene oxide and butylene oxide, more preferably propylene oxide.

<16>
The amount of alkylene oxide used in the production method is preferably 0.01 equivalents or more, more preferably 0.10 equivalents or more, still more preferably 0.20 equivalents or more, and preferably 50 equivalents, relative to 1 mol of AGU of cellulose. The method for producing a cellulose derivative according to <15>, wherein the method is more preferably 30 equivalents or less, still more preferably 20 equivalents or less, still more preferably 10 equivalents or less, still more preferably 5.0 equivalents or less.
<17>
The method for producing a cellulose derivative according to any one of <14> to <16> above, wherein the cellulose derivative is hydroxyalkyl cellulose.
<18>
The average number of moles of hydroxyalkyl groups added to the hydroxyalkyl cellulose is preferably 0.10 or more, more preferably 0.20 or more, still more preferably 0.50 or more, still more preferably 0.80 or more, and is preferable. The method for producing a cellulose derivative according to <17> above, wherein is 20 or less, more preferably 10 or less, still more preferably 8.0 or less, and even more preferably 5.0 or less.
<19>
Regenerated cellulose having a step of obtaining a cellulose mixture by the method according to any one of <1> to <13> above, and a step of mixing the cellulose mixture with a poor solvent for cellulose to reprecipitate cellulose. Manufacturing method.
<20>
The method for producing regenerated cellulose according to <19> above, wherein the poor solvent is a solvent having a single composition.

<21>
The method for producing regenerated cellulose according to <19> or <20> above, wherein the poor solvent is water or a polar solvent having a boiling point of less than 100 ° C. at normal pressure.
<22>
The method for producing regenerated cellulose according to <21> above, wherein the polar solvent is alcohol or acetone having 1 to 4 carbon atoms, preferably ethanol.
<23>
A cellulose mixture containing a raw material cellulose, a quaternary ammonium hydroxide and a solvent, wherein the solvent contains an organic solvent and contains water in a total amount of 100% by mass of the quaternary ammonium hydroxide and the solvent. The amount is less than 50% by mass, preferably 40% by mass or less, more preferably 25% by mass or less, still more preferably 10% by mass or less, still more preferably 7.5% by mass or less, still more preferably 5.0% by mass. Hereinafter, the cellulose mixture is more preferably 2.0% by mass or less.
<24>
Use of the cellulose mixture according to <23> above for the production of cellulose derivatives.
<25>
Use of the cellulose mixture according to <23> above for the production of regenerated cellulose.

Hereinafter, the present invention will be specifically described based on examples. In the following Examples and Comparative Examples, "%" means "mass%" unless otherwise specified.
The average degree of polymerization, crystallinity, water content, median diameter, average number of moles of hydroxyalkyl groups added, reaction selectivity, and water solubility were measured or calculated by the following methods.

(1) Measurement of Average Degree of Polymerization The viscosity average degree of polymerization of the raw material cellulose (pulp) used in Examples and Comparative Examples was measured by the method shown below.
(I) Preparation of measurement solution To a volumetric flask (100 mL), 0.5 g of cuprous chloride (manufactured by Kanto Chemical Co., Inc.) and 20 to 30 mL of 25% aqueous ammonia (manufactured by Aldrich) were added and completely dissolved. Later, 1.0 g of cupric hydroxide (manufactured by Kanto Chemical Co., Inc.) and 25% aqueous ammonia were added. This was stirred for 30-40 minutes at 25 ° C. to completely dissolve. Then, finely weighed pulverized pulp (dried under reduced pressure at 105 ° C. and 20 kPa [absolute pressure] for 12 hours) was added, and the aqueous ammonia was filled up to the marked line of the volumetric flask. It was dissolved by stirring with a magnetic stirrer at 25 ° C. for 12 hours. The amount of pulp added in the same manner was changed in the range of 20 to 500 mg to prepare different concentrations of measurement solutions.
(Ii) Measurement of Viscosity Average Degree of Polymerization The measurement solution obtained in (i) above is placed in an Ubbelohde viscometer and allowed to stand in a constant temperature bath (20 ± 0.1 ° C.) for 1 hour, and then the flow rate of the liquid. Was measured. From the flow time (t (seconds)) of the measurement solutions of various pulp concentrations (g / dL) and the flow time (t ₀ (seconds)) of the copper ammonia aqueous solution without pulp addition, at each concentration according to the following formula. The reduced viscosity (η _sp / c) was calculated from the following formula.
η _sp / c = (t / t _0-1 ) / c
(In the formula, c is the pulp concentration (g / dL).)
Further, the reduced viscosity was extrapolated to c = 0 to obtain the intrinsic viscosity [η] (dL / g), and the viscosity average degree of polymerization (DP _v ) was obtained from the following formula.
DP _v = 2000 × [η]
(In the formula, 2000 is a coefficient peculiar to cellulose.)

(2) Calculation of Crystallinity The crystallinity of cellulose is measured by measuring the X-ray diffraction intensity of each pulp using an X-ray diffractometer "RINT 2500VC X-RAY divercatometer" (manufactured by Rigaku) under the following conditions. Then, it was calculated based on the following formula.
Crystallinity (%) = [(I _22.6 −I _18.5 ) / I _22.6 ] × 100
[In the formula, I _22.6 shows the diffraction intensity of the lattice plane (002 plane) (diffraction angle 2θ = 22.6 °) of the cellulose I type crystal in X-ray diffraction, and I _18.5 is the amorphous part (diffraction angle 2θ =). It shows a diffraction intensity of 18.5 °). ]
The measurement conditions are X-ray source: Cu / Kα-radiation, tube voltage: 40 kV, tube current: 120 mA, measurement range: 2θ = 5 to 45 °, X-ray scan speed: 10 ° / min, for measurement. The sample was prepared by compressing pellets having an area of 320 mm ² × a thickness of 1 mm.

(3) Measurement of Moisture Content The water content in the raw material cellulose was measured using an electronic moisture meter "MOC-120H" (manufactured by Shimadzu Corporation). The measurement was performed at a temperature of 120 ° C., and the point at which the mass change rate for 30 seconds was 0.1% by mass or less was defined as the end point of the measurement. The value of the water content measured under the above conditions was converted into mass% with respect to the mass of the residue obtained by subtracting water from the raw material cellulose, and used as the water content.

(4) Cellulose content The content of the residual component obtained by subtracting water from the raw material cellulose was converted into mass% with respect to the mass of the raw material cellulose to obtain the cellulose content.

(5) Measurement of Median Diameter The median diameter of the powdered raw material cellulose (crushed pulp) was measured using a laser diffraction / scattering type particle size distribution measuring device “LA-920” (manufactured by HORIBA, Ltd.). After adding powdered raw material cellulose to ethanol and performing ultrasonic dispersion treatment for 1 minute, measurement was carried out using this dispersion as a sample.

(6) Calculation of Average Number of Additions of Hydroxyalkyl Groups The average value (average number of additions of moles) of hydroxypropyl cellulose (HPC) introduced with hydroxypropyl groups per AGU constituting the main chain of cellulose is the tenth. (Vi) Obtained from the values obtained according to the "Analytical Method for Hydroxypropyl Cellulose" described on page 47 of the revised Japanese Pharmacy.
Specifically, the hydroxypropoxy group content [formula (-OC ₃ H ₆ OH) = 75.09] (b (mol / g)) (%) of the purified HPC obtained in the examples is calculated as follows. Obtained from the formula.
b (mol / g) = hydroxypropoxy group content (%) obtained from gas chromatograph analysis / (75.09 × 100)
Next, the average number of moles (m) of hydroxypropyl groups added to HPC was calculated from the obtained value b and the following formula.
b = m / (162 + m × 58.08)
Gas chromatography measurement was performed using "GC-2014" (manufactured by Shimadzu Science Co., Ltd.). Further, "AOC-20i" (manufactured by Shimadzu Science Co., Ltd.) was used as an autosampler, and "HG260B" (manufactured by GL Sciences Co., Ltd.) was used as a hydrogen generator. The analysis conditions are as follows.
Column: "Silicone SE-30 30% Chromosorb W 60/80 AW-DMCS" (manufactured by Shimadzu Science Co., Ltd.)
Column temperature: 60 ° C (5 min) → 10 ° C / 1 min → 300 ° C (1 min)
Injector temperature: 250 ° C
Detector temperature: 320 ° C
Drive amount: 1 μL
The average value (average number of added moles) of the amount of hydroxybutyl groups introduced per AGU constituting the cellulose main chain of hydroxybutyl cellulose (HBC) was determined by the following method.
The hydroxybutoxy group content [formula (-OC ₄ H ₈ OH) = 89.11] (b'(mol / g)) (%) of the purified HBC obtained in the examples was calculated from the following formula. ..
b'(mol / g) = hydroxybutoxy group content (%) obtained from gas chromatograph analysis / (89.11 × 100)
Next, the average number of moles (m) of hydroxybutyl groups added to HBC was calculated from the obtained value b'and the following formula.
b'= m / (162 + m × 72.10)
Gas chromatography measurement was performed using "GC-2014" (manufactured by Shimadzu Science Co., Ltd.). Further, "AOC-20i" (manufactured by Shimadzu Science Co., Ltd.) was used as an autosampler, and "HG260B" (manufactured by GL Sciences Co., Ltd.) was used as a hydrogen generator. The analysis conditions are as follows.
Column: "Silicone SE-30 30% Chromosorb W 60/80 AW-DMCS" (manufactured by Shimadzu Science Co., Ltd.)
Column temperature: 60 ° C (5 min) → 10 ° C / 1 min → 300 ° C (1 min)
Injector temperature: 250 ° C
Detector temperature: 320 ° C
Drive amount: 1 μL

(7) Calculation of reaction selectivity The reaction selectivity when alkylene oxide is used as the reactant is calculated by the following formula from the input amount of alkylene oxide and the average number of moles of hydroxyalkyl groups of HPC or HBC obtained. Calculated.
Reaction selectivity (%) = average number of moles of hydroxyalkyl group added / [(alkylene oxide input amount (mol) / main chain AGU (mol)) x 100]

(8) Evaluation of water solubility 150 mg of HPC or HBC was precisely weighed, 50 ml of water and a stirrer were added, and the mixture was stirred overnight at room temperature with a magnetic stirrer. Then, it was centrifuged at 3000 rpm for 30 minutes using a centrifuge "H-28F" (manufactured by Kokusan Co., Ltd.). The obtained supernatant was freeze-dried, and the weight of the obtained solid content was measured to determine the weight fraction (%) of the water-soluble component. The water-soluble (%) shown in Table 1 is the weight fraction of the water-soluble component, and the higher the weight fraction, the better the water solubility.

Production Example 1 (Production of powdered raw material cellulose)
(1) Cutting treatment As a cellulose-containing raw material, a sheet-shaped wood pulp "BioflocHV +" (manufactured by Tembec, crystallinity: 82%, water content: 8.5% by mass, average degree of polymerization 1550) was used as a cutting machine "RK6-". It was cut into a chip shape of 3 mm × 1.5 mm × 1 mm using “800” (manufactured by Ogino Seiki Seisakusho Co., Ltd.).
(2) Drying treatment The chip-shaped raw material cellulose obtained by the cutting treatment of (1) above is dried using a twin-screw horizontal stirring dryer "NPD-3W (1/2)" (manufactured by Nara Kikai Seisakusho Co., Ltd.). did. The pulp was dried by continuous treatment under atmospheric pressure. At this time, steam at 150 ° C. was used as the heating medium of the dryer, and the supply rate of the chip-shaped raw material cellulose was 45 kg / h. The water content of the dry chip-shaped raw material cellulose obtained by the continuous treatment was 0.5% by mass.
(3) Coarse crushing treatment The dried raw material cellulose obtained by the drying treatment of (2) above is used in a continuous vibration mill "YAMT-200" (manufactured by Eura Techno Co., Ltd., capacity of first and second crushing chambers: 112 L). ) Was used for coarse crushing. In the first and second crushing chambers, 80 stainless steel round bar-shaped crushing media having a diameter of 30 mm and a length of 1300 mm were housed. The filling rate of the pulverization medium was 66.5%. Under the conditions of a continuous vibration mill having a frequency of 16.7 Hz, an amplitude of 13.4 mm, a temperature of 75 ° C., and a residence time of the raw material cellulose after drying for 2.6 minutes, the raw material cellulose after drying was charged at 20 kg / h. The obtained crudely pulverized cellulose had a median diameter of 191 μm and a crystallinity of 19%.
(4) Cellulose particle size reduction treatment The coarsely pulverized cellulose obtained by the coarse pulverization treatment of (3) above was reduced in particle size using a high-speed rotary fine pulverizer "KIIW-1 type" (manufactured by Dalton). .. A screen with a mesh opening of 0.7 mm was attached, the rotor peripheral speed was driven at 81 m / s, and coarsely pulverized cellulose was supplied from the raw material supply unit at a supply speed of 18 kg / h.
^{Next, a SUS screen with a sieve area of 0.196 m 2} and an opening of 150 μm was attached to a circular vibrating sieve machine “KGC-500” (manufactured by Kowa Kogyosho Co., Ltd.), and the frequency was 30 Hz (vibration speed 1800 r / min). It is driven with a one-sided amplitude of 3 mm in the vertical direction, a one-sided amplitude of 3 mm in the horizontal direction, and a weight phase angle of 60 °, and the raw material is supplied from the raw material supply unit at a supply speed of 14 kg / h to remove coarse powder and pass through a sieve. Was recovered as a powdery raw material cellulose (crystallization degree: 19%, water content: 1.5% by mass, average degree of polymerization: 855, median diameter: 83 μm).

Production Example 2 (Production of TBAH)
Weigh 13.9 g of tetrabutylammonium chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) in a beaker, add 500 ml of methanol (manufactured by Wako Pure Chemical Industries, Ltd.) to this, stir with a magnetic stirrer, and cool at room temperature. Dissolved in. To this, 56.7 g of a strongly ionic ion exchange resin (DOWNEX MONOSPHER (registered trademark) 550 (OH), manufactured by Wako Pure Chemical Industries, Ltd.) previously washed with 500 ml of methanol (manufactured by Wako Pure Chemical Industries, Ltd.). Was added and stirred at room temperature. The ion exchange resin was removed by filtration, methanol was distilled off with an evaporator at a bath temperature of 30 ° C., and then vacuum dried using a vacuum pump to obtain tetrabutylammonium hydroxide (TBAH).
The purity of TBAH is obtained by diluting 1.0 g of the obtained TBAH with 50 ml of ion-exchanged water, adding a 1% phenolphthalein ethanol solution to this, and performing neutralization titration with 1M hydrochloric acid (manufactured by Wako Pure Chemical Industries, Ltd.). Was calculated. The purity of the obtained TBAH was 70%. The remaining 30% is methanol.

Production Example 3 (Production of BTEAH)
Weigh 11.4 g of benzyltriethylammonium chloride (manufactured by Wako Pure Chemical Industries, Ltd.) in a beaker, add 500 ml of methanol (manufactured by Wako Pure Chemical Industries, Ltd.) to this, stir with a magnetic stirrer, and room temperature. Dissolved below. To this, 56.7 g of a strongly ionic ion exchange resin (DOWNEX MONOSPHER (registered trademark) 550 (OH), manufactured by Wako Pure Chemical Industries, Ltd.) previously washed with 500 ml of methanol (manufactured by Wako Pure Chemical Industries, Ltd.). Was added and stirred at room temperature. The ion exchange resin was removed by filtration, methanol was distilled off with an evaporator at a bath temperature of 30 ° C., and then vacuum dried using a vacuum pump to obtain benzyltriethylammonium hydroxide (BTEAH).
The purity of BTEAH is obtained by diluting 1.0 g of the obtained BTEAH with 50 ml of ion-exchanged water, adding a 1% phenolphthalein ethanol solution to this, and performing neutralization titration with 1M hydrochloric acid (manufactured by Wako Pure Chemical Industries, Ltd.). Was calculated. The purity of the obtained BTEAH was 68%. The remaining 32% is methanol.

Example 1
(Manufacturing of cellulose mixture)
Weigh 2.0 g of the powdered raw material cellulose obtained in Production Example 1 into a mortar, add 3.2 g of dimethyl sulfoxide (manufactured by Wako Pure Chemical Industries, Ltd.) to the raw material cellulose with a dropper, and mix with a pestle. The operation to do was repeated. After adding dimethyl sulfoxide, 3.2 g of TBAH having a purity of 70% (TBAH pure content 2.24 g, methanol 0.96 g) obtained in Production Example 2 is added to the mixture in several drops with a dropper and mixed with a pestle. Repeatedly, a cellulose mixture was obtained.
(Manufacturing of HPC)
The obtained cellulose mixture is transferred to a closed glass container, 0.29 g (0.4 equivalent / AGU) of propylene oxide (manufactured by Wako Pure Chemical Industries, Ltd.) as a reactant is added thereto, and the mixture is sealed, and then 50. The reaction was carried out at ° C. for 2 hours. This operation was repeated 4 more times and a total of 2.0 eq / AGU of propylene oxide was used in the reaction. The obtained crude HPC is neutralized with acetic acid (manufactured by Wako Pure Chemical Industries, Ltd.), and the neutralized product is purified using a dialysis membrane (manufactured by Wako Pure Chemical Industries, Ltd., molecular weight cut off of 8000). Freeze-drying was performed to obtain purified HPC.
The above-mentioned evaluation was performed on the obtained purified HPC. The results are shown in Table 1.

Example 2
In Example 1, the same method as in Example 1 was used except that the amount of dimethyl sulfoxide used was changed to 1.6 g and the amount of TBAH having a purity of 70% obtained in Production Example 2 was changed to 1.6 g. A cellulose mixture was obtained. Further, using this cellulose mixture, purified HPC was obtained in the same manner as in Example 1. Table 1 shows the results of the above-mentioned evaluation of the obtained purified HPC.

Example 3
In Example 1, the same method as in Example 1 was used except that the amount of dimethyl sulfoxide used was changed to 1.9 g and the amount of 70% pure TBAH obtained in Production Example 2 was changed to 4.5 g. A cellulose mixture was obtained. Further, using this cellulose mixture, purified HPC was obtained in the same manner as in Example 1. Table 1 shows the results of the above-mentioned evaluation of the obtained purified HPC.

Example 4
In Example 1, the same method as in Example 1 was used except that the amount of dimethyl sulfoxide used was changed to 0.64 g and the amount of 70% pure TBAH obtained in Production Example 2 was changed to 5.8 g. A cellulose mixture was obtained. Further, using this cellulose mixture, purified HPC was obtained in the same manner as in Example 1. Table 1 shows the results of the above-mentioned evaluation of the obtained purified HPC.

Example 5
A cellulose mixture was obtained in the same manner as in Example 1 except that 3.2 g of acetonitrile was used instead of 3.2 g of dimethyl sulfoxide. Further, using this cellulose mixture, purified HPC was obtained in the same manner as in Example 1. Table 1 shows the results of the above-mentioned evaluation of the obtained purified HPC.

Example 6
In Example 1, the amount of dimethyl sulfoxide used was changed to 2.58 g, and instead of 3.2 g of TBAH having a purity of 70% obtained in Production Example 2, 2.6 g of BTEAH having a purity of 68% obtained in Production Example 3 was used. A cellulose mixture was obtained in the same manner as in Example 1 except that (BDEAH pure content 1.8 g, methanol 0.8 g) was used. Further, using this cellulose mixture, purified HPC was obtained in the same manner as in Example 1. Table 1 shows the results of the above-mentioned evaluation of the obtained purified HPC.

Example 7
After obtaining a cellulose mixture by the same method as in Example 1, hydroxybutyl cellulose (HBC) was produced by the following method.
(Manufacturing of HBC)
The cellulose mixture was transferred to a closed glass container, and 0.45 g (0.5 equivalent / AGU) of the reactant 1,2-butylene oxide (manufactured by Tokyo Chemical Industry Co., Ltd.) was added thereto at 50 ° C. It was allowed to react for 2 hours. This operation was repeated once more and a total of 1.0 eq / AGU of 1,2-butylene oxide was used in the reaction. The obtained crude HBC is neutralized with acetic acid (manufactured by Wako Pure Chemical Industries, Ltd.), and the neutralized product is purified using a dialysis membrane (manufactured by Wako Pure Chemical Industries, Ltd., molecular weight cut-off 8000). Freeze-drying was performed to obtain purified HBC.
The above-mentioned evaluation was performed on the obtained purified HBC. The results are shown in Table 1.

Comparative Example 1
A cellulose mixture and purified HPC were obtained in the same manner as in Example 1 except that 3.2 g of water was used instead of 3.2 g of dimethyl sulfoxide. Table 1 shows the results of the above-mentioned evaluation of the obtained purified HPC.

Comparative Example 2
A cellulose mixture and purified HPC were obtained in the same manner as in Example 2 except that 1.6 g of water was used instead of 1.6 g of dimethyl sulfoxide in Example 2. Table 1 shows the results of the above-mentioned evaluation of the obtained purified HPC.

Note)
TBAH: Tetrabutylammonium Hydroxide BTEAH: Benzyltriethylammonium Hydroxide PO: Propylene Oxide BO: Butylene Oxide

From Table 1, it can be seen that when hydroxyalkyl cellulose, which is a cellulose derivative, is produced using the cellulose mixture obtained by the production method of the present invention, the obtained hydroxyalkyl cellulose has excellent water solubility and a high reaction selectivity. On the other hand, as in Comparative Examples 1 and 2, when the water content is 50% by mass or more in the total amount of 100% by mass of the quaternary ammonium hydroxide and the solvent, the water solubility and reaction of the hydroxyalkyl cellulose The selectivity decreases in both cases.

Example 8 (Production of Regenerated Cellulose)
1.0 g of acetonitrile (manufactured by Wako Pure Chemical Industries, Ltd.) and 1.0 g of TBAH with a purity of 70% obtained in Production Example 2 (TBAH pure content 0.70 g, methanol 0.30 g) in a glass container equipped with a stirrer. Was weighed and stirred at room temperature. 200 mg of the powdered raw material cellulose obtained in Production Example 1 was added thereto, and the mixture was stirred at room temperature for 1 hour to prepare a 1% by mass cellulose solution (cellulose mixture preparation step). Next, 50 ml of ion-exchanged water was added to a beaker equipped with a stirrer, and the prepared cellulose solution was added little by little with a dropper and reprecipitated to precipitate a solid substance (reprecipitation step). The solid was collected by filtration and dried under reduced pressure at 50 ° C. overnight to obtain a powdery solid.
Wide-angle X-ray diffraction pattern of the raw material pulp and the solid substance (regenerated cellulose) (measurement conditions: sample shape is powder, measuring equipment and measurement conditions are the same as those used to calculate the crystallinity of raw material cellulose). It is shown in FIG. In the wide-angle X-ray diffraction pattern of the solid matter obtained in Example 8, the cellulose type I diffraction seen in the X-ray diffraction pattern of the raw material pulp was not observed, but the cellulose type II diffraction was observed, and regenerated cellulose was obtained. You can see that.

When the cellulose mixture obtained by the production method of the present invention is used as a raw material for producing a cellulose derivative, a highly water-soluble cellulose derivative can be obtained with a high selectivity. The cellulose mixture is also suitably used for producing regenerated cellulose.

Claims (11)

A method for producing a cellulose mixture comprising a step of mixing a raw material cellulose with a quaternary ammonium hydroxide and a solvent, wherein the solvent contains an organic solvent and the total amount of the quaternary ammonium hydroxide and the solvent. The water content in 100% by mass is less than 50% by mass,
The raw material cellulose is in the form of powder, and the median diameter of the powdered raw material cellulose is 10 μm or more and 1000 μm or less.
The organic solvent contains a polar solvent, and the polar solvent contains an aprotic polar solvent.
The aprotic polar solvent comprises one or more selected from the group consisting of acetonitrile, dimethyl sulfoxide, N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, and γ-butyrolactone.
A method for producing a cellulose mixture, wherein the mass ratio of the quaternary ammonium hydroxide to the solvent is 30/70 to 60/40. The method for producing a cellulose mixture according to claim 1, wherein the polar solvent contains a protonic polar solvent. Claim 1 in which the aprotic polar solvent is at least one selected from the group consisting of acetonitrile, dimethyl sulfoxide, N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, and γ-butyrolactone. Or the method for producing a cellulose mixture according to 2. The method for producing a cellulose mixture according to claim 2, wherein the protic and aprotic polar solvent is at least one selected from the group consisting of methanol, ethanol, 1-propanol, and 2-propanol. The method for producing a cellulose mixture according to any one of claims 1 to 4, wherein the content of water in the cellulose mixture is 50% by mass or less based on the cellulose in the raw material cellulose. The method for producing a cellulose mixture according to any one of claims 1 to 5, wherein the quaternary ammonium hydroxide is a compound represented by the following general formula (1).

In the formula (1), R ^{1 to} R ⁴ are independently substituted or unsubstituted hydrocarbon groups having 1 or more and 24 or less carbon atoms. The method for producing a cellulose mixture according to claim 6, wherein the total number of carbon atoms ^{of R 1 to} R ⁴ in the general formula (1) is 4 or more and 48 or less. The method for producing a cellulose mixture according to any one of claims 1 to 7, wherein the content of the aprotic polar solvent in the polar solvent is 50% by mass or more and 100% by mass or less. A method for producing a cellulose derivative, which comprises a step of obtaining a cellulose mixture by the method according to any one of claims 1 to 8 and a step of mixing and reacting the cellulose mixture with a reactant. The method for producing a cellulose derivative according to claim 9, wherein the reactant is an alkylene oxide. A method for producing regenerated cellulose, which comprises a step of obtaining a cellulose mixture by the method according to any one of claims 1 to 8 and a step of mixing the cellulose mixture with a poor solvent for cellulose to reprecipitate cellulose. ..

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