JP3654527B2 - Method for producing phenol derivatives of lignin - Google Patents

Description

【数２】

【００７３】
Iwt（％）：導入フェノール(Wt％）
Pwt：PNBの重量(mg)
Ｐｍ：PNBの分子量＝151
Ｐｎ：PNBにおける芳香核H数＝4
Ｐｉ：PNBにおける芳香核4Hシグナルを示す領域(8.40〜7.80ppm)の積分値
Ci：クレゾールにおけるメチル基3Hシグナルを示す領域(2.30〜1.80ppm)の積分値
Ei：P-エチルフェノールにおけるエチル基のメチル3Hシグナルを示す領域（1.40〜0.80ppm）の積分値
En：P‐エチルフェノールにおけるエチル基のメチルプロトン数＝3
Ｅｍ：P‐エチルフェノールの分子量＝122
Ｌｗｔ：リグノフェール重量
Imo1／C₉：導入フェノール量は(mo1／C₉）
Lm：リグニン1ユニットの分子量＝2000（針葉樹）
【００７４】
２次リグノフェノール誘導体中のｐ−エチルフェノールの導入量を図１３に示す。
図１３に示すように、全ての２次リグノフェノール誘導体において、ｐ−エチルフェノールの導入が確認された。いずれの酸濃度においても、コントロール試料の方が高いｐ−エチルフェノール導入量を示した。このことは、超音波照射により、リグニンへのフェノール誘導体の導入が促進され、１次リグノフェノール誘導体中の残存活性側鎖が減少したことを示している。
【００７５】
【発明の効果】
本発明によれば、リグノセルロース系材料からリグニン誘導体を得るのに際して、リグニン誘導体の物性や生産効率等を制御できる技術を提供することができる。
【図面の簡単な説明】
【図１】リグノセルロース系材料中のリグニンにフェノール誘導体を導入して得られる各種リグノフェノール誘導体を例示する図である。
【図２】実施例１で得られたベイマツ由来のリグノフェノール誘導体の反応時間と重量平均分子量との関係を示すグラフである。
【図３】実施例１で得られたブナ由来のリグノフェノール誘導体の反応時間と重量平均分子量との関係を示すグラフである。
【図４】実施例１で得られたベイマツ由来のリグノフェノール誘導体の反応時間と導入クレゾール量との関係を示すグラフである。
【図５】実施例１で得られたブナ由来のリグノフェノール誘導体の反応時間と導入クレゾール量との関係を示すグラフである。
【図６】実施例３で得られたリグノフェノール誘導体の反応時間と収率を示すグラフである。
【図７】実施例４で調製した水不溶解区分の反応時間と収率を示すグラフである。
【図８】実施例４で得られたリグノフェノール誘導体の反応時間と収率との関係を示すグラフである。
【図９】実施例３において得られたリグノフェノール誘導体の反応時間と重量平均分子量との関係を示すグラフである。
【図１０】実施例４において得られたリグノフェノール誘導体の反応時間と重量平均分子量との関係を示すグラフである。
【図１１】絶乾木紛あたりのリグノフェノール誘導体含有組成物の反応時間と収率との関係を示すグラフである。
【図１２】実施例６で得た各種リグノフェノール誘導体含有組成物中のリグニン含有量のグラフを示す
【図１３】実施例８で得られた２次リグノフェノール誘導体におけるｐ−エチルフェノールの導入量を示すグラフである。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for separating and converting plant constituents, and more particularly to a technique for separating a lignocellulose matrix which is a cell wall constituent and converting it into a usable derivative.
[0002]
[Prior art]
Cell wall constituents that are the main constituents of plant bodies, that is, composite materials containing lignin and cellulose, hemicellulose, etc. (hereinafter referred to as lignocellulosic materials) are separated using phenol derivatives and acids. There is a technique for derivatization (see, for example, Patent Document 1 and Patent Document 2).
In this technique, a method called phase separation is used to separate lignin from the lignin-cellulose matrix. That is, the lignocellulosic material is previously solvated or sorbed with a phenolic compound, and the lignocellulosic material is brought into contact with an acid so that the phenolic compound is grafted onto the lignin and at the same time. Is separated from the matrix with cellulose.
In these methods, there is also a technique for improving the separation efficiency (Patent Document 3).
[0003]
[Patent Document 1]
JP-A-2-233701
[Patent Document 2]
Japanese Patent Laid-Open No. 9-278904
[Patent Document 3]
JP 2001-131201 A
[0004]
[Problems to be solved by the invention]
Currently, the physical properties and the like of the lignin derivative obtained by this method are largely derived from the derived lignocellulosic material, and the molecular weight, the introduction efficiency of the phenol compound, the yield and the like have not been controlled.
However, when a lignin derivative is to be obtained from a lignin-containing material by structural transformation accompanied by such phase separation, it is desired that the yield of lignin derivative, molecular weight, introduction rate of phenol compound, and the like can be controlled to some extent. In particular, when trying to obtain a lignin derivative industrially, an efficient reaction process is desired.
Therefore, an object of the present invention is to provide a technique capable of controlling physical properties, production efficiency, and the like of a lignin derivative when a lignin derivative is obtained from a lignocellulosic material.
[0005]
[Means for Solving the Problems]
The present inventors examined factors required for separation and conversion in separating lignocellulosic materials into cellulose and lignin derivatives, and with phenol derivatives that are mediums having high affinity for lignocellulosic materials. Focusing on the contact process with an acidic medium, which is an affinity process, a component separation medium from the lignin-cellulose complex and also a reaction medium, and examined the addition of physical energy such as ultrasonic waves. It was found that decomplexing by the conversion system of lignin matrix can be promoted. Further, the present inventors have found that the molecular weight, the introduction ratio of the phenol compound, and the like can be controlled in addition to the yield of the lignin derivative obtained by the phase separation conversion by ultrasonic irradiation.
That is, according to the present invention, the following means are provided.
[0006]
(1) A method for producing a phenol derivative of lignin,
A process of making lignocellulosic material compatible with a phenol derivative, and
A step of introducing a phenol derivative into lignin in a reaction system obtained by adding an acid to a lignocellulosic material previously affinityd with a phenol derivative;
The method of irradiating the mixed system containing the lignocellulosic material with ultrasonic waves in at least one of the steps.
(2) The method according to (1), wherein the affinity step is a step of solvating the lignocellulosic material in a liquid phase containing a phenol derivative.
(3) The method according to (1), wherein the affinity step includes a step of preliminarily penetrating a lignocellulosic material with a solvent containing a phenol derivative and a step of removing the solvent.
(4) The acid in the introduction step is added at least at a strength that can swell the lignin-cellulose matrix in the lignocellulosic material, and the mixed system in the introduction step is irradiated with ultrasonic waves. The method according to any one of 3).
(5) Before the introduction step, an acid having a strength that does not swell the lignin-cellulose matrix in the lignocellulosic material is added, and the mixed system in the introduction step is irradiated with ultrasonic waves. (1) to (3) The method in any one of.
(6) A composition comprising a phenol derivative of lignin obtained by the method according to any one of (1) to (5) and a carbohydrate derived from the lignocellulosic material.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The method for producing a lignophenol derivative according to the present invention is such that, in the step of making a lignocellulosic material compatible with a phenol derivative, the mixed system of the lignocellulosic material and the phenol derivative is irradiated with ultrasonic waves, or the phenol derivative is preliminarily applied. It is characterized by irradiating ultrasonic waves to a mixed system in which an acid is added to a lignocellulosic material.
By irradiating the mixed system in the affinity step with ultrasonic waves, the contact between the phenol derivative and the lignocellulosic material can be enhanced, and the sorption and / or solvation of the phenol derivative to the lignocellulosic material can be promoted. .
Moreover, by contacting the lignocellulosic material with affinity with a phenol derivative with an acid, the phenol derivative is introduced into the lignin of the lignin-cellulose matrix to transform the structure, and at the same time, the ligand is separated from the complex by cleavage of the benzyl aryl ether bond. The Conventionally, the lignocellulosic material, which is affinityd with a phenol derivative by external force, specifically mechanical stirring, has been brought into contact with the acid. However, by irradiating this mixed system with ultrasonic waves, the acid-induced carbohydrate It is considered that the decomposition and the improvement of the contact probability between lignin and acid promote the decomposition of the lignin-cellulose complex in which the lignin phase is affinityd with the phenol derivative, and at the same time promote the introduction of the phenol derivative into the lignin.
[0008]
The rate of introduction of the phenol derivative can be increased by promoting decomposition. In particular, by adding an acid at a strength that swells the lignin-cellulose matrix, the conversion / separation of the lignophenol derivative by ultrasonic irradiation can be speeded up.
Furthermore, ultrasonic irradiation is useful in other aspects. That is, the acid strength used in introducing the phenol derivative can be reduced. Thereby, the process of removing the acid from the aqueous layer can be made more efficient. In addition, the decrease in acid strength enables the preparation of various lignophenol derivatives, and the carbohydrate content can be easily adjusted in the composition of the lignophenol derivative and the carbohydrate derived from the lignocellulosic material. .
[0009]
Hereinafter, embodiments of the present invention will be described in detail.
(Lignocellulosic material)
The “lignocellulose-based material” used in the present invention is not particularly limited as long as it is a material containing a lignin-cellulose complex which is a constituent component of a plant cell wall. For example, various materials that are made of wood, mainly wood, such as wood powder, chips, agricultural wastes and industrial wastes associated with wood resources such as waste materials, scraps, and waste paper can be mentioned. In addition, as a kind of wood to be used, any kind of wood such as conifers and hardwoods can be used. Furthermore, the whole or a part of various herbaceous plants such as kenaf, rice, sugar cane, corn, and related agricultural and industrial wastes such as bagasse can be used.
[0010]
(Lignophenol derivative and its production process)
The lignophenol derivative means a polymer containing a 1,1-bis (aryl) propane unit in which a phenol derivative is introduced by a C—C bond at the C1 position of an arylpropane unit (C9 unit) of lignin. . It is a kind of polyphenol.
The lignophenol derivative is also a mixture of lignin-derived polymers obtained by reaction and separation from the lignin-containing material, and the amount and molecular weight of the introduced phenol derivative in the obtained polymer are determined based on the lignin-containing material (typical). In particular, it is lignocellulosic material) and is said to vary frequently depending on the reaction conditions.
[0011]
A lignophenol derivative can be usually obtained by contacting a lignin-containing material, preferably a lignocellulosic material, which has been affinityd by a predetermined phenol derivative with an acid. As for more general description of lignophenol derivatives and the production process thereof, JP-A-2-23701, JP-A-9-278904 and International Publication WO99 / 14223, 2001-64494, No. 2001-261839, 2001-131201, and 2001-34233 (the contents described in these patent documents are all incorporated herein by reference).
[0012]
In this production process, while maintaining the lignocellulosic material on the phenol derivative phase side, it was selectively brought into contact with an acid, the decomposed cellulose was distributed to the acid side, and the phenol derivative was introduced through contact with the acid. It is a process that simultaneously achieves structural transformation and separation of lignin by partitioning lignin to the phenol derivative side. In constructing such a reaction system, it is particularly preferable that the lignocellulosic material is previously affinityd with a phenol derivative. Here, affinity is used to mean solvation, permeation, and absorption and adsorption (also referred to as sorption). That is, in such a reaction system, the complex state of lignocellulose is relaxed, and at the same time, the phenol derivative is selectively grafted to the C1 position (benzyl position) of the arylpropane unit of natural lignin to produce a lignophenol derivative. At the same time, it can be separated into cellulose and lignophenol derivatives.
According to this method, a lignophenol derivative having a 1,1-bis (aryl) propane unit in which the phenol derivative is grafted to the C1 position of the phenylpropane unit of lignin at the ortho position or para position of the used phenol derivative is obtained. be able to. In the obtained lignophenol derivative, an arylpropane unit to which no phenol is grafted usually remains.
[0013]
Various methods can be exemplified as a method for obtaining a lignophenol derivative from a lignocellulosic material.
In any of these forms, the phenol derivative is introduced into the lignin in the step of making the lignocellulosic material compatible with the phenol derivative and the reaction system obtained by adding an acid to the lignocellulosic material previously affinityd with the phenol derivative. Process.
These methods can be distinguished in terms of whether the affinity step is one step or two steps, and can also be distinguished in the separation method of the obtained lignophenol derivative.
In addition, although four types of typical methods are illustrated in the following examples, it is not intended to limit to these four types of methods.
[0014]
The first method is the method described in JP-A-2-233701. This method comprises a single affinity step. The one-step affinity step is a step in which a liquid phenol derivative is infiltrated into a lignocellulosic material such as wood flour, and lignin is solvated with the phenol derivative. The phenol derivative can also be diluted with an inert solvent such as benzene.
Next, the introduction process will be described. The introduction step is a step of adding a concentrated acid (as described above, for example, 72% sulfuric acid) to the lignocellulosic material and mixing to hydrolyze the cellulose component and introduce a phenol derivative into the lignin.
In this step, a phenol derivative obtained by solvating lignin and a concentrated acid dissolving a cellulose component form a two-phase separation system. The lignin solvated by the phenol derivative is contacted with the acid only at the interface where the phenol derivative phase is in contact with the concentrated acid phase, and a reaction occurs. That is, the cation at the side chain C1 position (benzyl position), which is a highly reactive site of the basic structural unit of lignin generated by interfacial contact with an acid, is attacked by the phenol derivative. As a result, the phenol derivative is introduced at the C1 position by a C—C bond, and the benzyl aryl ether bond is cleaved to reduce the molecular weight. As a result, the molecular weight of lignin is reduced, and at the same time, a lignophenol derivative in which a phenol derivative is introduced at the C1 position of the basic structural unit is produced in the phenol derivative phase. From this phenol derivative phase, a lignophenol derivative is extracted. A lignophenol derivative is obtained as an aggregate of low molecular weight forms of lignin in which the benzyl aryl ether bond in lignin is cleaved to reduce the molecular weight. It is known that some phenol derivatives are introduced into the benzyl position through the phenolic hydroxyl group.
FIG. 1 shows that various lignophenol derivatives can be obtained by subjecting natural lignin having an arylpropane unit to phase separation.
[0015]
Extraction of the lignophenol derivative from the phenol derivative phase can be performed, for example, by the following method. That is, the precipitate obtained by adding the phenol derivative phase to a large excess of ethyl ether is collected and dissolved in acetone. The acetone insoluble part is removed by centrifugation or the like, and the acetone soluble part is concentrated. The acetone soluble part is dropped into a large excess of ethyl ether, and the precipitate section is collected. The solvent is distilled off from this precipitation section to obtain a lignophenol derivative. The crude lignophenol derivative can be obtained by simply removing the acetone soluble part by vacuum distillation.
[0016]
The second and third methods include a two-step affinity process. In the two-step affinity process, a lignocellulosic material is infiltrated with a solvent (for example, ethanol or acetone) in which a solid or liquid phenol derivative (for example, p-cresol or 2,4-dimethylphenol) is dissolved. And then the solvent is distilled off.
Next, a concentrated acid is added to the lignocellulosic material to dissolve the cellulose component (corresponding to the introduction step). As a result, as in the first method, the lignin solvated with the phenol derivative is attacked by the phenol derivative with the cation at the highly reactive site (side chain C1 position) of the lignin generated upon contact with the concentrated acid. Derivatives are introduced. In addition, the benzyl aryl ether bond is cleaved to lower the molecular weight of lignin. The properties of the obtained lignophenol derivative are the same as those obtained by the first method. Then, in the same manner as in the first method, the lignophenol derivative introduced with the phenol derivative is extracted with a liquid phenol derivative. Extraction of the lignophenol derivative from the liquid phenol derivative phase can be carried out in the same manner as in the first method (this is referred to as the second method). Alternatively, the entire reaction solution after the concentrated acid treatment is put into excess water, the insoluble sections are collected by centrifugation, deacidified and then dried. The lignophenol derivative is extracted by adding acetone or alcohol to the dried product. Further, the soluble segment is dropped into excess ethyl ether or the like in the same manner as in the first method to obtain a lignophenol derivative as an insoluble segment (this is referred to as a third method). In the above, specific examples of the method for preparing the lignophenol derivative have been described. However, the present invention is not limited to these, and it can be prepared by a method in which these are appropriately improved.
[0017]
The fourth method is a method described in Japanese Patent Application Laid-Open No. 2001-131201. A mixture containing a lignocellulosic material, a phenol derivative, and an acid (also referred to as a reaction system in this specification) is added with benzene, xylene, After mixing with an inert low-boiling hydrophobic organic solvent selected from toluene, hexane, or a mixture thereof, the mixture is centrifuged and separated into three layers, and the lignophenol derivative fraction is separated into a band-like aggregated second layer. It is a method to take. The affinity step and the introduction step until the reaction system is obtained can be carried out in the same manner as in the first to third methods. Further, the separated lignophenol derivative can be divided into an ether-insoluble fraction and then separated into an acetone-soluble fraction as shown in the first and second methods. Thus, it can be poured into excess water to obtain a water-insoluble fraction. Preferably, as in the third method, after fractionating into a water-insoluble fraction, the acid is washed and removed, and a lignophenol derivative is finally obtained in a fraction that dissolves in acetone or the like.
[0018]
(Phenol derivative)
As the lignophenol derivative with which the lignocellulosic material is preliminarily affinityd, a monovalent phenol derivative, a divalent phenol derivative, a trivalent phenol derivative, or the like can be used.
Specific examples of the monovalent phenol derivative include phenol which may have one or more substituents, naphthol which may have one or more substituents, and one or more substituents. A good anthrol, an anthroquinone all optionally having one or more substituents, and the like can be mentioned.
Specific examples of the divalent phenol derivative include catechol which may have one or more substituents, resorcinol which may have one or more substituents, and one or more substituents. Examples include good hydroquinone.
Specific examples of the trivalent phenol derivative include pyrogallol, which may have one or more substituents.
In the present invention, one or more of monovalent phenol derivatives, divalent phenol derivatives and trivalent phenol derivatives can be used, and monovalent phenol is preferably used.
[0019]
The kind of the substituent that the monovalent to trivalent phenol derivative may have is not particularly limited, and may have an arbitrary substituent, but is preferably an electron-withdrawing group (halogen atom). For example, a lower alkyl group-containing substituent having 1 to 4 carbon atoms, preferably 1 to 3 carbon atoms. Considering the introduction rate, a non-bulky substituent such as a methyl group or an ethyl group is preferable. Examples of the lower alkyl group-containing substituent include a lower alkyl group (such as a methyl group, an ethyl group, and a propyl group) and a lower alkoxy group (such as a methoxy group, an ethoxy group, and a propoxy group). Further, it may have an aromatic substituent such as an aryl group (such as a phenyl group). Further, it may be a hydroxyl group-containing substituent.
[0020]
These phenol derivatives are introduced into the phenylpropane unit by bonding a carbon atom in the ortho or para position to the phenolic hydroxyl group to the carbon at the C1 position of the phenylpropane unit of lignin. Therefore, in order to secure the introduction site, it is preferable that at least one of the ortho and para positions does not have a substituent.
[0021]
From the above, in the present invention, in addition to the unsubstituted phenol derivative, at least one phenol derivative in various substituted forms having at least one unsubstituted ortho-position or para-position may be appropriately selected and used. it can.
[0022]
Preferred examples of the phenol derivative include p-cresol, 2,6-dimethylphenol, 2,4-dimethylphenol, 2-methoxyphenol (Guaiacol), 2,6-dimethoxyphenol, catechol, resorcinol, homocatechol, pyrogallol. And phloroglucinol. P-cresol is preferable.
[0023]
(acid)
The acid used in the introduction step is not particularly limited. Examples thereof include sulfuric acid, hydrochloric acid, phosphoric acid, p-toluenesulfonic acid, trifluoroacetic acid, trichloroacetic acid, formic acid and the like. Preferably, the acid is strong enough to swell the lignin-cellulose matrix by nature or concentration. Here, the object to be swollen with acid is mainly cellulose. Examples of such strong acids include 65 wt% or more sulfuric acid, 85 wt% or more phosphoric acid, 35 wt% or more hydrochloric acid, p-toluenesulfonic acid, trifluoroacetic acid, trichloroacetic acid, and formic acid. Preferred acids include 72 wt% sulfuric acid, 95 wt% phosphoric acid, 45 wt% trifluoroacetic acid and formic acid.
In order to efficiently recover cellulose, hemicellulose-derived water-soluble polysaccharides, oligosaccharides, and monosaccharides, it is preferable to use sulfuric acid, which suppresses the action on cellulose and retains its higher order structure to some extent. For recovery, it is preferable to use an acid having a low acid strength such as phosphoric acid.
[0024]
In some cases, a mixed system in which an acid is added to a phenol derivative and a lignocellulosic material at a strength that does not swell the lignin-cellulose matrix may be prepared at the beginning of the introducing step or prior to the introducing step. This is because, by irradiating the mixed system with ultrasonic waves, the decomposition of the lignin-cellulose matrix may be promoted prior to the introduction of the phenol derivative. Here, the acid that does not swell the lignin-cellulose matrix may be weaker than the strength of the acid that can swell the lignin-cellulose matrix. Specific examples include sulfuric acid of less than 65 t%, phosphoric acid of less than 85 wt%, hydrochloric acid of less than 35 wt%, p-toluenesulfonic acid, trifluoroacetic acid, trichloroacetic acid, and formic acid. Preferable acids include 60 wt% or less sulfuric acid, 80 wt% or less phosphoric acid, 30 wt% or less hydrochloric acid, trifluoroacetic acid and formic acid. In the mixed system prior to the introduction step, a weaker acid strength may be used.
[0025]
The frequency of introduction of the phenol derivative varies depending on the presence / absence, position, size, etc. of the substituent of the phenol derivative to be introduced. Therefore, the introduction frequency can be adjusted. In particular, the introduction frequency can be easily adjusted by steric hindrance due to the size of the substituent. When the introduction position or the like is to be controlled using a substituent, the introduction frequency can be easily adjusted depending on the number of carbon atoms and the branched form when a lower alkyl group is used as the substituent. When the substituent is a methyl group, the introduction position can be controlled while maintaining a high introduction frequency.
[0026]
The general and general properties of the primary derivative obtained from the lignocellulosic material are listed below. However, the lignophenol derivative in the present invention is not intended to be limited to those having the following properties.
(1) The weight average molecular weight is about 2000 to 20000.
(2) There is almost no conjugated system in the molecule, and the color tone is very light. Typically a pale pink white powder.
(3) It has a solid-liquid phase transition point at about 170 ° C. derived from conifers and at about 130 ° C. derived from hardwoods.
(4) Easily soluble in methanol, ethanol, acetone, dioxane, pyridine, tetrahydrofuran, dimethylformamide and the like.
[0027]
(Ultrasonic irradiation)
(Ultrasonic irradiation in the affinity process)
In the method of the present invention, it is preferable that the lignocellulosic material and / or the phenol derivative is irradiated with ultrasonic waves in the affinity step of the lignocellulosic material with the phenol derivative. Preferably, in the state where the lignocellulosic material and the phenol derivative are present simultaneously, both are irradiated with ultrasonic waves. By this ultrasonic irradiation, the phenol derivative can be efficiently and sufficiently infiltrated into the lignocellulosic material, and a state in which both are sufficiently compatible can be obtained easily and quickly. As a result, the phenol derivative can be efficiently introduced into the lignin in the subsequent step of introducing the phenol derivative into the lignin.
[0028]
Such an affinity step can be applied to any of the affinity steps exemplified in the first method and the second method described above. In the first method, ultrasonic waves can be irradiated in a state where a liquid phenol derivative is infiltrated into the lignocellulosic material, or in a state where the lignocellulosic material is immersed in the phenol derivative. In the second method, an organic solvent (for example, acetone, ethanol, benzene, hexane, toluene, xylene, or a mixture thereof) in which a phenol derivative is dissolved in a lignocellulosic material is immersed or penetrated. It is possible to irradiate with ultrasonic waves in a state in which the organic solvent is distilled off, preferably before the organic solvent is distilled off. The organic solvent can be distilled off while irradiating with ultrasonic waves.
[0029]
In the present invention, the voltage and frequency of the ultrasonic wave to be used are not particularly limited, and irradiation may be performed under conditions that can improve the affinity between the phenol derivative and the lignocellulosic material. If the power and frequency of an ultrasonic generator that can be normally used (power of about 100 W to about 1500 W, frequency of about 20 kHz to about 40 kHz), the above-mentioned effect can be obtained by irradiation for several tens of seconds to several tens of minutes.
The form of ultrasonic irradiation is not particularly limited, but the oscillator may be in a liquid phenol derivative, or the oscillator is placed in a water bath or the like in which a container containing the liquid phenol derivative is immersed. And may be irradiated.
Further, mechanical agitation may be additionally accompanied with ultrasonic irradiation. Note that the ultrasonic irradiation is not necessarily continuous, and may be intermittent. Further, it is not required to be used over the entire time of the affinity process, and may be used only in a part of the affinity process.
[0030]
(Ultrasonic irradiation in the introduction process)
Moreover, in this invention, it is preferable to irradiate an ultrasonic wave with respect to the reaction system obtained by adding an acid to the lignocellulosic material affinityd previously in the introduction process of the said phenol derivative. When irradiating the reaction system with ultrasonic waves, it is preferable to irradiate the entire area with ultrasonic waves. Alternatively, it is also preferable to accompany other stirring and mixing means, specifically, mechanical stirring means using a stirrer or stirring blades, stirring means using a jet or the like.
[0031]
In the step of introducing a phenol derivative into lignin, the deligation of the lignin-cellulose matrix in the lignocellulosic material can be promoted by irradiating with ultrasonic waves. For this reason, when the acid is sufficiently acidic to swell the cellulose region in the matrix, the acid quickly penetrates, so that the cellulose quickly swells and the lignin is in a large molecular weight state. It becomes easy to be separated from. Therefore, a lignophenol derivative having a relatively high molecular area can be efficiently obtained by ultrasonic treatment.
[0032]
Irradiation with ultrasonic waves also improves the contact probability between lignin and an acid, and has an aspect that a production amount of a lignophenol derivative and a high introduction rate can be obtained at an early stage. Improvement of the introduction rate is also promoted by promoting decomposition.
Therefore, the introduction rate obtained under the same conditions except for simply using mechanical agitation should be achieved in about one-quarter to one-half time by carrying out the introduction step with appropriate ultrasonic irradiation. Can do.
Also, by irradiating with ultrasonic waves under acidity sufficient to swell cellulose in the introduction process, lignophenol derivatives having a high molecular weight and a high introduction rate of phenol derivatives can be easily obtained even at a relatively early stage of the introduction process. Can get to.
When ultrasonic irradiation is performed in the affinity process, the lignocellulosic material and the phenol derivative have a good affinity, so that the deligation of the lignin-cellulose matrix by contact with an acid can be introduced more quickly. In addition, even after the introduction, it is stably distributed to the phenol derivative phase, and separation from cellulose can be facilitated.
[0033]
By performing ultrasonic irradiation in the introducing step in the first method and the fourth method, it is possible to promote the distribution of the produced lignophenol derivative to the phenol derivative phase. That is, phase separation is achieved early. This is presumably due to the efficient introduction of the phenol-introduced lignin to promote conversion.
[0034]
The voltage and frequency of ultrasonic irradiation in the introduction process are not particularly limited as in the affinity process. The contact probability between the phenol derivative and the lignocellulosic material is several tens of seconds to several tens of times if the power and frequency of an ultrasonic generator that can be used normally (power is about 100 W to about 1500 W, frequency is about 20 kHz to about 40 kHz). It can be sufficiently improved by irradiation for about a minute.
The form of ultrasonic irradiation is not particularly limited, but it may be in a state in which an oscillator is infiltrated into a liquid phenol derivative, or an oscillator is placed outside a container containing a liquid phenol derivative. May be. Similarly to the affinity step, mechanical stirring can be additionally accompanied with ultrasonic irradiation, and the irradiation may be continuous or intermittent. Further, it is not required to be used over the entire time of the introduction process, and may be used only in a part of the introduction process. Note that, as described above, the ultrasonic irradiation promotes the decomposition of the lignin-cellulose matrix and the introduction of the lignophenol derivative, so that the ultrasonic irradiation step is preferably performed at least at the initial stage of the introduction step. More preferably, it is performed in the first half of the introduction step.
In addition, the effect by ultrasonic irradiation can also be adjusted by changing the intensity | strength of stirring or dispersion means other than an ultrasonic wave in an introduction process.
[0035]
In addition, as for the irradiation of an ultrasonic wave, as a front stage or a part thereof, a lignocellulosic material previously affinityd with a phenol derivative and a dilute acid solution containing water or an acid that hardly hydrolyzes cellulose. It can also be performed on a mixed solution of After such preliminary irradiation, an acid is added so that the acidity is appropriate, that is, the lignin-cellulose matrix can be swollen, and an introduction step (with or without ultrasonic irradiation) is performed. Can do. Such preliminary ultrasonic irradiation is irradiation in a state in which lignin and cellulose are prevented from immediately decomposing or reacting as in the case of ultrasonic irradiation performed in the affinity process, but the combined state of lignin and cellulose is alleviated or released. Promote. For this reason, the phenol derivative and introduction | transduction in an introduction | transduction process, and decomposition of a lignin-cellulose matrix can be accelerated | stimulated.
[0036]
In the introduction process involving ultrasonic irradiation, the following effects are produced depending on the strength of the acid used.
For example, when the lignin-cellulose matrix can be sufficiently swollen, in other words, under acidic conditions where cellulose can be sufficiently dissolved, for example, when sulfuric acid having a concentration of 72 wt% or more is used, the introduction step requires When sonication is performed, a lignophenol derivative can be obtained at a high yield very early, and the amount of lignophenol derivative to be finally produced can be increased. In particular, the ratio of lignophenol derivatives in the water-insoluble section in the third method can be easily increased (in other words, the cellulose content is decreased), and the subsequent lignophenol fractionation step can be facilitated. .
[0037]
In addition, when ultrasonic treatment is not used in the introduction process, it is difficult to efficiently produce a lignophenol derivative at a concentration that can dissolve cellulose reliably. However, ultrasonic waves are irradiated in the introduction process. Thus, even with sulfuric acid of 62 wt% or more and less than 72 wt% (preferably 65 wt% or more, and preferably 70 wt% or less), cellulose can be sufficiently dissolved and the introduction process can be accelerated. Therefore, in addition to reducing the amount of acid used, for example, as in the fractionation method of the third method, the reaction system after introduction of the phenol derivative is poured into a large amount of water to form a water-insoluble category, and from the water-insoluble category In removing the acid by washing, there is an advantage that the washing step can be simplified.
[0038]
Furthermore, when sulfuric acid of 62 wt% or more and less than 72 wt% is used, the phenol derivative is improved as the conditions (time and strength) of ultrasonic irradiation increase the yield of the lignophenol derivative and the introduction efficiency of the phenol derivative. The introduction rate and the amount of lignophenol derivative produced vary (increase) over a wide range. That is, by adjusting the sonication conditions under such an acidity, the introduction efficiency of the phenol derivative and the production amount of the lignophenol derivative can be easily adjusted in a wide range.
That is, by combining the adjustment of acid strength with the ultrasonic irradiation conditions in the introduction step, the yield of lignophenol derivative, the introduction rate of the phenol derivative, and the molecular region of the resulting lignophenol derivative can be easily adjusted.
[0039]
Further, when adopting the preparative method of the third method, the acid strength is such that the strength of the cellulose in the complex cannot be hydrolyzed, for example, about 60 wt% sulfuric acid or sulfuric acid having a concentration below that, A water-insoluble fraction in which the cellulose content exceeds the lignin or lignophenol derivative content can be easily obtained by adjusting the sonication conditions. In particular, it is possible to selectively and effectively hydrolyze only the amorphous region of cellulose or hemicellulose in a lignocellulosic material by water and make it water-soluble, thereby obtaining a water-insoluble fraction containing a highly crystalline region of cellulose. it can.
Furthermore, in the case of about 65 wt% sulfuric acid, the lignin (or lignophenol derivative) content exceeds the cellulose content from the water-insoluble fraction in which the cellulose content exceeds the lignin (or lignophenol derivative) content by adjusting the ultrasonic treatment conditions. A water-insoluble fraction can be easily obtained. Furthermore, in the case of sulfuric acid of about 72 wt% or more, a water-insoluble fraction in which the lignin content exceeds the cellulose content can be easily obtained by adjusting the ultrasonic treatment conditions.
In the case of 65 wt% or more of sulfuric acid, natural lignin, which is a network polymer, can be converted into a linear lignophenol derivative at the same time as it swells and hydrolyzes to the crystalline region of cellulose. For this reason, a uniform composite system of the lignophenol derivative and the carbohydrate segment can be easily obtained. Such a composite system exhibits thermoplasticity and can be preferably used as a composition for molding, filling and the like.
[0040]
In addition, the irradiation of the ultrasonic wave in this invention is performed with respect to the mixed system in any one process of an affinity process and an introduction process, and can also be performed in both processes. Preferably, ultrasonic irradiation is performed at least in the introduction step.
[0041]
(Lignophenol derivative composition)
The water-insoluble fraction (water-insoluble fraction composition) obtained by introducing the acidic reaction mixture obtained in the introduction step in the second to fourth methods into water is derived from a lignocellulose-based material in addition to the lignophenol derivative. It contains carbohydrates such as water-insoluble cellulose, and can be said to be a lignophenol derivative-containing composition.
As described above, the content ratio of the lignophenol derivative and the carbohydrate such as cellulose in the water-insoluble fraction can be adjusted by a combination of sonication and acid strength. At the same time, the introduction rate and molecular weight of the phenol derivative can be adjusted.
Therefore, by performing ultrasonic treatment in the introduction step, a lignophenol derivative-containing composition in which the content ratio of the lignophenol derivative and the carbohydrate and the introduction ratio of the phenol derivative is adjusted as necessary can be obtained.
From the above, according to the present invention, it is also possible to provide a method for producing a lignophenol derivative-containing composition in which ultrasonication is performed in the affinity step and / or the introduction step.
[0042]
【Example】
Hereinafter, specific examples of the present invention will be described. The present invention is not limited to the following examples.
(Example 1: Preparation of lignophenol derivative by the first method)
Two kinds of defatted wood flour (Douglas fir (60-80 mesh) and 1 g each of Beech (60-80 mesh) are precisely weighed, transferred to a 50 ml beaker, added with 10 ml of p-cresol, and irradiated with ultrasonic waves for 5 minutes. Cresol was sorbed onto the wood flour.The centrifuge tube was fixed to an ultrasonic device adjusted to a water temperature of 30 degrees, and a stirring bar was inserted from above and 20 ml of 62 wt% sulfuric acid was added while stirring at 400 rpm. The reaction time after the addition of sulfuric acid was set to 5, 10, 15, 30, 45, 60 minutes, and ultrasonic waves were continuously applied during that time, and the ultrasonic irradiation was performed with an output of 100 W and 40 kHz. I went there.
The reaction solution after the reaction was centrifuged, the cresol layer was dropped into diethyl ether, the precipitate was dissolved in acetone, the acetone solution was concentrated, dropped again into diethyl ether, and the precipitate was collected by centrifugation.
A control sample was prepared by conducting the same experiment as above except that no ultrasonic wave was used during the acid treatment.
[0043]
(Example 2)
For the lignophenol derivative (lignocresol) obtained by ultrasonic treatment in Example 1 and the control lignophenol derivative, the weight average molecular weight was measured by GPC, and the amount of cresol introduced was measured by NMR.
The results are shown in FIGS.
[0044]
As shown in FIGS. 2 and 3, the weight average molecular weight of the control sample was higher than that of the sonication sample particularly in the early stage of the reaction, and the difference between the two was slight in the 60-minute treatment sample. In contrast, as shown in FIGS. 4 and 5, the amount of cresol introduced was approximately higher than that of the control sample in the sonicated sample.
From these facts, it is apparent that the introduction rate of cresol in the sonication sample is high as a result of the accelerated introduction rate of cresol in the sonication sample, particularly in the initial to first half of the reaction.
Further, regarding the difference in the weight average molecular weight between the sonication sample and the control sample, the sonication conditions in Example 1 are mild, although there is an effect of promoting the decomposition of the lignin-cellulose matrix by the sonication. On the other hand, it reflects the result of efficient (rapid) introduction of cresol by ultrasound.
That is, under the sonication conditions of Example 1, deligation of the lignin-cellulose matrix was promoted slowly, and a large molecular region lignophenol derivative was slowly formed and separated, while the introduction of cresol was well promoted, It is considered that the initial weight average molecular weight was lower than that of the control sample because the low molecular weight lignophenol derivative having high introduction efficiency was produced and separated simultaneously or at an early stage. In addition, since the introduction of cresol is slower in the control sample than in the sonicated sample, the high molecular weight lignophenol derivative with a low cresol introduction rate is extracted in advance, while the reaction is accelerated. It is considered that the initial molecular weight was increased as a result of the relatively low molecular region lignophenol derivative into which cresol was gradually introduced with a high frequency gradually being extracted later than the previous polymer region lignophenol derivative.
[0045]
(Example 3: Preparation of lignophenol derivative by the first method)
As a lignocellulosic material, Batsuga (Tsuga canadensis) wood flour was used. 10 ml of p-cresol was added to 1 g of baitsuga defatted wood flour (corresponding to the absolute dry weight) and stirred for 5 minutes at 150 rpm and the lignin in the material was solvated with cresol. Next, 72 wt% sulfuric acid was added, and the mixture was vigorously stirred at 500 rpm, irradiated with ultrasonic waves (20 kHz, 180 W) with an ultrasonic generator (BRANSON SONIFIER450D), and reacted for 15 minutes, 20 minutes, and 40 minutes, respectively. I let you. In addition, ultrasonic irradiation was performed for a maximum of 20 minutes, with the reaction times of 15 minutes and 20 minutes being continuously irradiated for the entire reaction time, and for the system of 40 minutes being irradiated only for the first 20 minutes.
After the reaction, the reaction product was centrifuged, and the upper cresol phase was added dropwise to diethyl ether with cooling and stirring. The obtained insoluble fraction was extracted with acetone for 24 hours, and the filtrate was concentrated under reduced pressure and then added dropwise to cooled diethyl ether with stirring to obtain a lignophenol derivative.
A control sample was obtained in the same manner as in the above method except that ultrasonic irradiation was not performed during the acid treatment.
[0046]
The following were observed during the reaction with the acid.
That is, after the lignin solvation step with p-cresol, when the acid was added, the viscosity of the system increased rapidly and continued to decrease after several minutes. This is due to the fact that the higher-order structure of carbohydrates swells with acid and then becomes a low molecular weight by hydrolysis. In the ultrasonic irradiation sample, the initially increased viscosity decreased in a very short time. In other words, these results indicate that the aqueous medium rapidly penetrated into the carbohydrate molecules with higher-order structures by the microscopic vibration of the ultrasonic wave, and the swelling and hydrolysis were promoted.
When the reaction system is centrifuged after the acid treatment, the intermediate layer decreases as the treatment time is extended, and a clear green-colored phenol phase and a yellow aqueous phase are clearly separated, increasing the transparency of the aqueous phase. did. This is because the polymer carbohydrate and lignophenol mixed in the intermediate layer as a molecular mixture or complex migrate to the phenol phase and aqueous phase, respectively, as the phase separation reaction proceeds, and the carbohydrate in the aqueous phase is highly hydrolyzed. It can be said that this is because it was converted to water-soluble.
[0047]
(Example 4: Preparation of lignophenol derivative by the second method)
After sorption of 3 mol times (about 0.48 g) of p-cresol per lignin C9 unit to 1 g of degreased wood flour (corresponding to the absolute dry weight) used in Example 3, 72 wt% sulfuric acid was added, and ultrasonic waves were added. While stirring at 500 rpm, ultrasonic waves (20 kHz, 180 W) were irradiated with an ultrasonic generator (BRANSON SONIFIER450D) for 15 minutes, 20 minutes, and 40 minutes, respectively. In addition, ultrasonic irradiation was performed for a maximum of 20 minutes, with the reaction times of 15 minutes and 20 minutes being continuously irradiated for the entire reaction time, and for the system of 40 minutes being irradiated only for the first 20 minutes.
The reaction product is poured into a large excess of deionized water, the insoluble fraction is washed by centrifugation, deoxidized, and lyophilized to obtain a water insoluble fraction composition (lignophenol derivative and carbohydrate derived from lignocellulosic material). Contained). Further, this composition was extracted with acetone, and the dissolution section was concentrated under reduced pressure, and then dropwise added to ice-cooled diethyl ether with stirring to obtain a lignophenol derivative.
A control sample was obtained in the same manner as in the above method except that ultrasonic irradiation was not performed during the acid treatment.
In the reaction step with the acid, as in Example 3, the reaction mixture was reduced in viscosity by extending the reaction time and irradiating with ultrasonic waves, and this tendency was remarkable in the sonicated sample. In addition, when the reaction mixture was dispersed in a large excess of water after the phase separation reaction, the dispersibility was improved by extending the reaction time and irradiating with ultrasonic waves, and the yield of the insoluble fraction was small.
[0048]
(Example 5)
The lignophenol derivative yield and the weight average molecular weight (by GPC) of the lignophenol derivative sample and the control sample prepared in Example 3 and Example 4 were measured. The results are shown in FIGS.
[0049]
(Yield of lignophenol derivatives, etc.)
As shown in FIG. 6, the yield of the lignophenol derivative in Example 3, ie, lignocresol, was significantly higher in the sonicated sample than in the control sample at any treatment time.
In other words, since the yield of the system to which ultrasonic waves were added increased by about 2 times compared to the control, ultrasonic waves as external energy contributed to the increase in the contact frequency of the phenol-acid phase, and the carbohydrate classification It can be said that it effectively promotes the hydrolysis of lignin and the phenol grafting reaction of lignin. In addition, since the lignophenol was already induced in a high yield of 80% or more in 15 minutes from the start of the reaction, the effect of ultrasonic irradiation was manifested in the very initial stage of the phase separation reaction, which It can be said that the typical phase separation reaction time was shortened.
[0050]
Moreover, as shown in FIG. 7, the yield of the carbohydrate-lignophenol composite sample obtained as the water-insoluble section was clearly reduced for the ultrasonic irradiation sample of Example 4. The yield was about 20 to 26% per wood flour regardless of the reaction time. In other words, the irradiation of ultrasonic waves promotes the hydrolysis of carbohydrates, effectively converts them into water-soluble low-molecular sugar classes, and suppresses aggregation between water-insoluble carbohydrate-lignophenol composite particles. Therefore, the yield is thought to have decreased.
On the other hand, as shown in FIG. 8, the yield of lignophenol extracted and purified from the obtained water-insoluble fraction composition was almost the same in all treatments. From this, it was found that fragmentation due to carbohydrate hydrolysis and selective phenol grafting reaction to the lignin C1 position and cleavage of the bond between aryl ether units was effectively promoted by ultrasonic irradiation. These results indicate that the hydrolysis of carbohydrates and the phenol grafting reaction of lignin are significantly accelerated by ultrasound.
[0051]
(Weight average molecular weight of lignophenol derivative)
As shown in FIG. 9, in the control sample of Example 3, the weight average molecular weight of the obtained lignophenol gradually increased with the extension of the reaction time, whereas the lignophenol obtained by sonication was used. Phenol was higher in molecular weight and polydispersed than the control, and became almost constant after a reaction time of 20 minutes. This indicates that the addition of ultrasonic waves rapidly releases the higher-order structure of the carbohydrate, and the converted lignophenol is transferred into the phenol phase in an overall and effective manner. On the other hand, in the control sample with a slow hydrolysis rate of carbohydrates, only the relatively low molecular weight portion of the converted lignophenol was transferred to the phenol phase, so it was thought that it had a low molecular weight at the beginning of the reaction.
[0052]
Moreover, as shown in FIG. 10, the same tendency as the weight average molecular weight (FIG. 9) in the sample of Example 3 was recognized also in each sample obtained in Example 4. However, the difference in molecular weight between the presence and absence of ultrasonic irradiation in Example 4 was small, and the sonicated sample was slightly higher in both weight average molecular weight and dispersion ratio than the control. This is thought to be due to the fact that, as a result of the loss of highly converted lignophenol in the water dispersion process due to the addition of ultrasonic waves, only a relatively limited section was obtained as the final product.
[0053]
(Example 6) Preparation of a lignophenol derivative
(1) Affinity process-sorption of phenol derivatives
Coniferous pine (Pseudotsuga menziessi, hereinafter referred to as Douglas fir) is pulverized in an ultra-centrifugal crusher ZM100 manufactured by Retsh, and then passed through an 80-mesh sieve manufactured by IIDA Corporation to obtain 80-mesh wood powder. It was.
The wood flour was extracted with an ethanol: benzene = 1: 2 (V / V) solution using a Soxhlet extractor for 48 hours. After extraction, the wood powder was spread on a stainless steel vat, and the solvent was completely distilled off in a fume hood. Furthermore, it dried at 105 degreeC with the ventilation dryer for 24 hours, and the absolutely dry wood flour was obtained.
[0054]
Put 3g of absolute dry wood flour into a 100ml separable flask and add about 30ml of phenol derivative acetone solution (Lignin C).₉(Including a phenol derivative equivalent to 3 mol times per unit). Next, in order to remove bubbles existing inside the wood flour, the mixture was stirred a little with a stirring blade, and the beaker was covered with aluminum foil and parafilm, and allowed to stand for about 24 hours. After standing, the mixture was stirred vigorously in a fume hood to completely remove acetone. A sample obtained by distilling acetone was used as a phenol derivative sorption wood flour.
[0055]
(2) Introduction process of phenol derivative-sulfuric acid treatment
While adding 60 ml of 60 wt%, 65 wt%, and 72 wt% sulfuric acid aqueous solution adjusted to 30 ° C in advance to the phenol derivative sorption wood flour subjected to affinity treatment in (1), stirring with a stirrer at 500 rpm for a predetermined time. The ultrasonic wave was radiated by an ultrasonic generator (BRANSON SONIFIER450D, 20 kHz, output 180 W), and the introduction process was performed in three treatment times of 5 minutes, 10 minutes, and 20 minutes. After completion of the process, each content was put into a large excess of water (about 600 ml, under forced stirring) in an 11-volume Erlenmeyer flask, the sulfuric acid concentration was lowered to 10% or less, and the mixture was stirred for about 1 hour. In addition, except not irradiating an ultrasonic wave, operation was performed similarly to the above and it was set as each control.
[0056]
(3) Deoxidation treatment
Transfer the contents of the Erlenmeyer flask to a centrifuge tube (made of polypropylene) with deionized water, and separate into water-soluble (including suspended solids) and water-insoluble sections by centrifugation [8800 rpm (10560G), 20 min, 5 ° C]. did. After separation, the soluble section (including suspended matter) in the centrifuge tube is taken out into a 51-volume Erlenmeyer flask using a Komagome pipette, and the water-insoluble section is further added with deionized water, stirred and centrifuged, and unreacted phenol derivative And acid was removed as a soluble fraction. The soluble fraction taken in a 5 liter Erlenmeyer flask was allowed to stand for about 1 day, and the supernatant was taken into a beaker with a suction filtration bell so as not to disturb the precipitate, and filtered with a glass fiber filter paper whose constant weight had been obtained in advance. After that, the constant amount of suspended matter remaining on the filter paper was measured.
[0057]
(4) Drying water-insoluble sections
The insoluble fraction after deoxidation treatment is transferred to a plastic container whose constant weight has been measured in advance using a small amount of deionized water, freeze-dried, and then dried under reduced pressure on diphosphorus pentoxide to obtain the constant weight. The yield based on wood flour was measured.
[0058]
(5) Observation of reaction system in ultrasonic irradiation in introduction process
[Sonication using 60wt% sulfuric acid aqueous solution]
In the reaction system using 60 wt% sulfuric acid, the control sample turned yellow green immediately after the addition of the sulfuric acid aqueous solution, and turned slightly dark green in about 5 to 6 minutes. Regarding the wood powder particles, the wood powder particles were confirmed even after the sulfuric acid treatment. In the sonicated sample, similar particles could be confirmed after the reaction. In addition, when the aqueous sulfuric acid solution was added, an increase in viscosity in the sample could not be confirmed regardless of the presence or absence of ultrasonic irradiation. These results mean that 60% aqueous sulfuric acid cannot cause sufficient swelling of the plant cell wall. After water dispersion, the color of the treated sample tended to turn red as the treatment time changed to 5 minutes, 10 minutes, and 20 minutes in each of the control sample and the sonication sample. Further, the sonicated sample was darker than the control sample. The red coloration of this sample is derived from the degree of conversion of lignin molecules, which are color-forming components in wood.
[0059]
[Sonication using 65wt% sulfuric acid aqueous solution]
In the treatment using the 65 wt% sulfuric acid aqueous solution, the control sample turned green immediately after the addition of the sulfuric acid aqueous solution, and then turned darker in about 3 to 4 minutes. In the ultrasonic treatment sample, the wood powder particles could not be confirmed in about 5 to 6 minutes, but in the control sample, the wood powder particles could not be confirmed in the treatment time of 10 minutes to 13 minutes. After water dispersion, the color of each treated sample turned red as the treatment time increased to 5 minutes, 10 minutes, and 20 minutes. As in the case of 60 wt% sulfuric acid treatment, the sonicated sample was darker than the control sample. Further, in the control sample, a white precipitation section was confirmed when the insoluble section was collected. This white section was also confirmed in the 5 minute and 10 minute samples of sonication, but not in the 20 minute sonication. This white section is considered to be due to aggregation of the poorly hydrolyzed carbohydrate section in the plant cell wall, and the white section of this carbohydrate was not confirmed in the 20 minute treated sample. It has been shown that hydrolysis of is promoted. The red coloration of the phase-separated sample is derived from the degree of conversion of lignin molecules, which are color forming components in wood, as in the case of 60 wt% sulfuric acid treatment.
[0060]
[Sonication using 72wt% sulfuric acid aqueous solution]
In the treatment using the 72 wt% sulfuric acid aqueous solution, unlike the case of adding the 60% sulfuric acid aqueous solution or the 65% sulfuric acid aqueous solution, the color changed to a considerably dark green immediately after the sulfuric acid aqueous solution was added. Then, it darkened a little in about 4-5 minutes. In the sonication sample, wood powder particles could not be confirmed in about 5-6 minutes, and in the control sample, it could not be confirmed in 9-11 minutes. After water dispersion, the color of the phase separation treated sample was green. The color of the sonicated sample did not change as the treatment time increased to 5 minutes, 10 minutes, or 20 minutes, but in the control sample, the treatment time increased to 5 minutes, 10 minutes, or 20 minutes. It turned green. In the control sample, when the treatment time was 5 minutes or 10 minutes, the white section confirmed during the 65 wt% sulfuric acid treatment was confirmed, but when the treatment time was 20 minutes, the white section was not confirmed. . In the sonicated sample, the white section observed during the 65 wt% sulfuric acid treatment was not confirmed. From this, it was shown that the 72 wt% sulfuric acid aqueous solution has the ability to sufficiently hydrolyze carbohydrates, and that the hydrolysis rate of carbohydrates was accelerated by ultrasonic energy.
[0061]
It should be noted that this is only an inference and does not restrict the present invention, but the color change after the addition of the above lignin acid is due to the coniferyl aldehyde present in the initial green color of the lignin. It is considered that when one molecule of p-cresol is introduced, the conjugated system in the molecule is extended. Furthermore, the color changes to dark green over time because the introduction of p-cresol occurs sufficiently and the generation of various types of conjugated systems can increase the absorption wavelength of light. It is thought to be caused by. In addition, the decrease in the brightness of the sonicated sample is considered to be caused by the fact that the hydrolysis of the carbohydrate, which is a white component, progresses to become an oligomer-level sugar having a low polymerization degree, thereby dissolving in the solvent. . The difference in color between the synthesized phase-separated samples is considered to be caused by the difference in the degree of oxidation and the degree of dispersion of the converted lignin molecules.
[0062]
(6) Yield of water-insoluble fraction (composition containing lignophenol derivative)
FIG. 11 shows a graph of the yield of the lignophenol derivative-containing composition per dry wood powder.
When a 60 wt% sulfuric acid aqueous solution was used, the sonicated sample showed a slightly lower yield than the control sample. The decrease in yield due to the treatment with 60% sulfuric acid is considered to have occurred as a result of the hemicellulose section and the amorphous section of cellulose in the wood having low resistance to acid being hydrolyzed by acid and flowing into the aqueous phase.
[0063]
When a 65 wt% sulfuric acid aqueous solution was used, the control sample showed a yield decreasing tendency (that is, a gradual decreasing tendency) almost the same as that during the 60 wt% sulfuric acid treatment. On the other hand, the yield of sonicated samples showed a significant decrease in yield. For the control sample, the 65 wt% sulfuric acid aqueous solution can swell the crystalline region of cellulose and the cellulose section is not fully hydrolyzed. The cause is considered to be. Significant yield reduction in sonicated samples promotes cell wall swelling and hydrolysis by 65 wt% sulfuric acid, which promotes the hydrolysis of carbohydrate segments due to increased sonic energy and increased contact between carbohydrate segments and acids. This is thought to be due to the fact that
[0064]
When the 72 wt% sulfuric acid aqueous solution was used, the control sample showed a yield decreasing tendency almost the same as the ultrasonic irradiation 65 wt% sulfuric acid treated sample. This indicates that the 72% aqueous sulfuric acid solution has the ability to cause cell wall swelling and more fully hydrolyze carbohydrate segments. On the other hand, in the case of the sonicated sample, even if the treatment time was increased to 5 minutes, 10 minutes, and 20 minutes, the yield did not change significantly. It is estimated that the decomposition rate was accelerated and the reaction reached equilibrium in about 5 minutes.
[0065]
(Example 7)
Measurement of lignin content in lignophenol derivative composition
About 200 mg of each composition of Example 6 which has been sufficiently dried is precisely weighed into a 10 ml sample tube, 3 ml of 72% sulfuric acid aqueous solution is added little by little with a glass rod, and the reaction is homogeneous in a 20 ° C. water bath. The reaction was allowed to proceed for 4 hours with sufficient agitation to proceed. After the reaction, it was quantitatively transferred to a 200 ml Erlenmeyer flask marked in advance to 115 ml, and deionized water was added to dilute the sulfuric acid concentration to 3%. The diluted processed product is heated with a gas burner to keep the sulfuric acid concentration at 3% and to remove carbohydrate-derived furfural and methylfurfural from the system. Therefore, deionized water is appropriately used without using a Liebig cooler. Boiled for 2 hours while adding. After the treatment, the content is filtered using a constant weight lG4 glass filter, the insoluble matter is washed with hot water, dried at 105 ° C, the constant weight is measured, and the amount of acid-insoluble lignin in the phase-separated sample Asked. The filtrate was measured for UV absorption at 205 nm with JASCOV-520, the amount of acid-soluble lignin was determined from the following formula, and the total amount of lignin was calculated as the sum of the amount of acid-insoluble lignin.
B = A / (110 × D)
Lignin (%) = B × V × 100 / (1000 × W)
A: Absorbance
D: Dilution rate
V: Total filtrate volume (ml)
W: Sample weight (g)
[0066]
FIG. 12 shows a graph of lignin content in the lignophenol derivative-containing composition.
Blackening was observed in all samples immediately after adding the sulfuric acid aqueous solution. In the sample using 60 wt% sulfuric acid, there was a viscosity at the beginning of the reaction irrespective of the presence or absence of ultrasonic irradiation, but in both the 65 wt% and 72 wt% sulfuric acid treated samples, the expression of viscosity was no longer present when acid was added. I was not able to admit. This is because the cell wall was not sufficiently swollen during the treatment with 60 wt% sulfuric acid, so that viscosity was produced only when 72 wt% sulfuric acid was added later, and the cell wall was already swollen during the treatment with 65 wt% sulfuric acid and 72 wt% sulfuric acid. It is considered that viscosity increase did not occur even when 72 wt% sulfuric acid was added in the latter stage.
[0067]
At the stage of diluting the sulfuric acid concentration to 3 wt%, the sonicated sample was blackened compared to the control sample, but turned red with boiling. This is considered to be because secondary denaturation was suppressed by the conversion of lignin.
Overall, the lignin content tended to increase as the processing time in the introduction process was extended. This corresponds to the longer the reaction time, the more carbohydrate is hydrolyzed and the lower molecular weight carbohydrate fraction flows out into the aqueous phase. Moreover, the acid-soluble lignin showed a higher value than usual. This is because a low molecular weight fraction that could not be self-condensed due to the introduction of a phenol derivative at the C1 position which is the active side chain in the lignin matrix by sonication and the secondary denaturation was suppressed, flowed into the filtrate. It is thought to be caused by.
[0068]
Example 8 Introduction of an additional phenol derivative into a lignophenol derivative
The introduction of this additional phenol derivative, that is, the second conversion treatment is performed to test the amount of active side chain remaining in the first lignophenol derivative obtained by the first conversion treatment already performed. This is the method. In this example, two types of phenol derivatives are introduced into the lignin matrix by a phase separation process using another phenol derivative different from the phenol derivative used in the primary treatment. Hereinafter, the degree of cell wall release and the degree of lignin conversion during the primary treatment were examined by comparing the frequency of introduction of the phenol derivatives introduced into the lignin matrix by the primary conversion treatment and the secondary transformation treatment.
[0069]
A specified amount of the composition (primary treatment sample) obtained in Example 6 (400 mg for the 72 wt% sulfuric acid treatment sample with a small total mass, 600 mg for the 65 wt% sulfuric acid treatment sample with ultrasonic irradiation, and 700 mg for the others) Weigh accurately in a 50 ml centrifuge tube, and there is a prescribed amount of phenol derivative (mixed medium of ethylphenol: benzene = 7: 3) (72 ml% sulfuric acid-treated sample with a small total mass), ultrasonic irradiation 65 wt% sulfuric acid-treated sample 6 ml, others 7 ml), and stirred for about 10 minutes so as to strike with a wing for a stirring frame. After that, add a specified amount of 72 wt% sulfuric acid aqueous solution that has been pre-heated at 30 ° C (8 ml for 72 wt% sulfuric acid treated sample with a small total mass, 12 ml for 65 wt% sulfuric acid treated sample, 14 ml for others), about 1 After stirring for a minute, it was placed on a stirrer and stirred in a water bath at 30 ° C. for a total of 60 minutes (500 rpm). After stirring, the mixture was separated into an organic phase and an aqueous phase by centrifugation [25 ° C., 3500 rpm (2200 G), 3 minutes].
[0070]
150 ml of diethyl ether is added to a 200 ml Erlenmeyer flask, and the organic phase is added dropwise with vigorous stirring with a stirrer while cooling with water, and then a phenol derivative is added to a several ml reaction vessel for interfacial cleaning, followed by centrifugation [25 ° C., 3500 rpm ( 2200G), 3 minutes] and the organic phase was added dropwise to ether. Washing was performed 3 times in total. After that, the oily substance settled and stirred until the supernatant liquid became clear. However, when the supernatant was not clear even after stirring for 1 hour, the insoluble matter was recovered by centrifugation [5 ° C., 3500 rpm (2220 G), 10 minutes]. The supernatant is removed, and the precipitate and the container are further washed twice with about 15 ml of diethyl ether. Then, 40-60 ml of acetone is added to the precipitate, and the mixture is stirred until completely dissolved. Washed with acetone. The supernatant was transferred to a centrifuge tube, centrifuged (5 ° C., 3500 rpm (2220 G), 5 minutes), and then filtered using glass fiber filter paper. Then, transfer to a 100 ml eggplant flask, concentrate to about 10 ml with an evaporator, add dropwise to diethyl ether, collect the resulting precipitate by centrifugation (5 ° C, 3500 rpm (2220G), 5 minutes), precipitate for washing Diethyl ether was added to the product and washed about 3 times.
The resulting precipitate was stored at room temperature in a dark place for 1 day, and diethyl ether was removed. Then, it dried under reduced pressure on niline pentoxide with the centrifuge tube, measured the constant weight, and calculated | required the yield. This was made into the secondary lignophenol derivative.
[0071]
(Example 9) Measurement of introduction amount of phenol derivative
About 20 mg of various secondary lignophenol derivatives and about 3 mg of p-nitrobenzaldehyde (PNB) as an internal standard substance are precisely weighed into a screw vial with an lmI Teflon liner (Teflon is a registered trademark) and weighed with an lml volumetric pipette. 150 μl of hydrogenated pyridine was added and completely dissolved. After dissolution, 450 μl of deuterated chloroform containing 0.03% tetramethylsilane was added using a 1 ml volumetric pipette. After confirming complete dissolution, the sample solution was filtered with cotton, put into an NMR measuring tube (diameter 5 mm), and measured with an ALPHAFT NMR Spectrometer (manufactured by JEOL).
[0072]
The introduction rate of p-ethylphenol was determined by the following formulas (1) and (2).
[Expression 1]

[Expression 2]

[0073]
Iwt (%): Introduced phenol (Wt%)
Pwt: PNB weight (mg)
Pm: Molecular weight of PNB = 151
Pn: H number of aromatic nucleus in PNB = 4
Pi: integrated value of region (8.40-7.80 ppm) showing aromatic nucleus 4H signal in PNB
Ci: integrated value of the region showing the methyl group 3H signal in cresol (2.30 to 1.80 ppm)
Ei: Integration value of the region showing the methyl 3H signal of the ethyl group in P-ethylphenol (1.40 to 0.80 ppm)
En: Number of methyl protons in the ethyl group in P-ethylphenol = 3
Em: Molecular weight of P-ethylphenol = 122
Lwt: Lignofail weight
Imo1 / C₉: The amount of phenol introduced is (mo1 / C₉)
Lm: Molecular weight of 1 unit of lignin = 2000 (conifers)
[0074]
FIG. 13 shows the amount of p-ethylphenol introduced into the secondary lignophenol derivative.
As shown in FIG. 13, introduction of p-ethylphenol was confirmed in all secondary lignophenol derivatives. The control sample showed a higher p-ethylphenol introduction amount at any acid concentration. This shows that introduction of a phenol derivative into lignin was promoted by ultrasonic irradiation, and the residual active side chain in the primary lignophenol derivative was reduced.
[0075]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, when obtaining a lignin derivative from a lignocellulosic material, the technique which can control the physical property, production efficiency, etc. of a lignin derivative can be provided.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating various lignophenol derivatives obtained by introducing a phenol derivative into lignin in a lignocellulosic material.
2 is a graph showing the relationship between the reaction time and the weight average molecular weight of the lignophenol derivative derived from bay pine obtained in Example 1. FIG.
3 is a graph showing the relationship between the reaction time and the weight average molecular weight of the beech-derived lignophenol derivative obtained in Example 1. FIG.
4 is a graph showing the relationship between the reaction time of lignophenol derivatives derived from bay pine and the amount of introduced cresol obtained in Example 1. FIG.
FIG. 5 is a graph showing the relationship between the reaction time of the beech-derived lignophenol derivative obtained in Example 1 and the amount of cresol introduced.
6 is a graph showing the reaction time and yield of the lignophenol derivative obtained in Example 3. FIG.
7 is a graph showing the reaction time and yield of the water-insoluble section prepared in Example 4. FIG.
8 is a graph showing the relationship between the reaction time and yield of the lignophenol derivative obtained in Example 4. FIG.
9 is a graph showing the relationship between the reaction time and the weight average molecular weight of the lignophenol derivative obtained in Example 3. FIG.
10 is a graph showing the relationship between the reaction time and the weight average molecular weight of the lignophenol derivative obtained in Example 4. FIG.
FIG. 11 is a graph showing the relationship between the reaction time and yield of a lignophenol derivative-containing composition per dry wood powder.
12 shows a graph of lignin content in various lignophenol derivative-containing compositions obtained in Example 6. FIG.
13 is a graph showing the amount of p-ethylphenol introduced into the secondary lignophenol derivative obtained in Example 8. FIG.

Claims (5)

A method for producing a phenol derivative of lignin,
A step of making a lignocellulosic material compatible with a phenol derivative, and a step of introducing a phenol derivative into lignin in a reaction system obtained by adding an acid to a lignocellulosic material previously made affinity with a phenol derivative;
A method of irradiating a mixed system containing a lignocellulosic material with ultrasonic waves in at least one of the steps. The method according to claim 1, wherein the affinity step is a step of solvating the lignocellulosic material in a liquid phase containing a phenol derivative. The method according to claim 1, wherein the affinity step comprises a step of preliminarily impregnating a lignocellulosic material with a solvent containing a phenol derivative and a step of removing the solvent. The acid in the introduction step is added at least with a strength capable of swelling the lignin-cellulose matrix in the lignocellulosic material, and the mixed system in the introduction step is irradiated with ultrasonic waves. The method described in 1. In the front | former stage of the said introduction | transduction process, the acid of the intensity | strength which does not swell a lignin-cellulose matrix in the said lignocellulosic material is added, and ultrasonic waves are irradiated to the mixing system in the said introduction | transduction process. the method of.

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