JP2004137347A6 - Method for producing phenol derivatives of lignin - Google Patents

Abstract

An object of the present invention is to provide a technique capable of controlling the introduction ratio of a phenol compound to be introduced and the introduction ratio of two or more phenol compounds when a phenol derivative of lignin is obtained from a lignocellulosic material.
(A) a step of adding an acid to a lignocellulosic material previously affinityd with a first phenol compound to obtain a primary lignin phenol derivative; Adding an acid to the n-th lignin phenol derivative to obtain an (n + 1) -th lignin phenol derivative, wherein n is a total of N times from 1 to N (N is an integer of 1 or more). The step (b) is sequentially performed, and an (n + 1) -th lignin phenol derivative is obtained in each step (b).
[Selection diagram] FIG.

Description

計算式（１）
【数２】

計算式（２）
【数３】

計算式（３）
【数４】

計算式（４）
【００７２】
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：ｐ−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
Ｃｎ：ｐ−クレゾールにおけるメチル基のプロトン数＝３
Ｃｍ：ｐ−クレゾールの分子量＝１０８
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
ｓｉ：ｐ−クレゾールのメチルプロトンシグナルとｐ−エチルフェノールにおけるエチル基のメチレンプロトンのシグナルを示す領域（２．６０〜１．８０ｐｐｍ）の積分値Ｌｗｔ：リグノフェール重量
Ｉｍｏ１／Ｃ_９：導入フェノール量は（ｍｏ１／Ｃ_９）
Ｌｍ：リグニン１ユニットの分子量＝２０００（針葉樹）
【００７３】
２次リグノフェノール誘導体中のｐ−クレゾールの導入量を図６及び図７に示す、ｐ−エチルフェノールの導入量を図８に示す。また、ｐ−クレゾールとｐ−エチルフェノールの導入量を合わせて図９及び図１０に示す。なお、図６及び７は、それぞれ計算式（２）及び（３）によりそれぞれ求められたｐ−クレゾール導入量に基いている。同様に図９及び１０も、それぞれ計算式（２）及び（３）によりそれぞれ求められたｐ−クレゾール導入量に基いている。
【００７４】
図６〜１０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、第２のフェノール化合物であるｐ−エチルフェノールの導入が確認された。図８に示すように、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、１次処理時において超音波照射により、リグニンへの第１のフェノール化合物であるｐ−クレゾールの導入が促進され、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】
また、第１のフェノール化合物であるｐ−クレゾールの導入量に着目すると、６０ｗｔ％硫酸処理試料では、両者において大きな差は見られなかった。また、６５ｗｔ％硫酸処理試料では、超音波処理試料の方が導入量がやや多かった。一方、７２ｗｔ％硫酸処理試料では、超音波処理試料の方が導入量が多いが、いずれも、おおよそ１０分で導入量の増加が停止した。これは、７２ｗｔ％硫酸は十分に植物細胞壁を膨潤してリグニンの分解を促進するため、２次リグノフェノール誘導体中の低分子量画分であってフェノール化合物の導入量が高い部位がエーテル可溶画分に流出したためであると思われる。超音波処理試料は１０分を境に導入量が減少し、コントロール試料は１０分以降も導入量が増加する傾向があった。
【００７６】
また、図９及び１０に示すように、導入フェノール化合物の総量は、７２ｗｔ％硫酸処理試料において最も高かった。これは、１次変換時で十分にセルロース及びリグニンの複合状態が緩和され、リグニンへのフェノール化合物や酸のアクセスビリティーが向上して、１次リグノフェノール誘導体におけるフェノール化合物が高度に導入された結果であるといえる。
また、図９及び図１０から明らかなように、１次処理において使用する酸の強度が高いほど、第１のフェノール化合物の導入率が高く、第２のフェノール化合物の導入率が低かった。第１のフェノール化合物と第２のフェノール化合物との比率が顕著に変化した。
さらに、超音波処理を行わなかったコントロール試料と超音波処理試料とを対比すると、超音波処理試料においては、全体的に第１のフェノール化合物の導入量が高いとともに、導入量の総量も高かった。
以上の結果によれば、使用する酸の強度や超音波処理の有無等を１次変換工程と２次変換工程において変化させることにより、それぞれの工程におけるフェノール化合物の導入量を調節でき、結果として２種類以上のフェノール化合物の導入比率を制御できることがわかった。特に、相対的に多くの導入量を得たいフェノール化合物にあっては、高い強度でかつ超音波照射を行う１次変換工程にて導入することが好ましいこともわかった。また、２種類以上のフェノール化合物の導入率を近似させるかあるいは高度に制御するには、１次工程側、あるいは前段側の工程において、中程度あるいは弱い酸強度で超音波処理条件あるいは超音波処理の有無をコントロールすることにより可能であることもわかった。
【図面の簡単な説明】
【図１】リグノセルロース系材料のリグニンにフェノール化合物を導入して得られる各種のリグノフェノール誘導体を示す図である。
【図２】１次変換工程（（ａ）工程）及び２次変換工程（（ｂ）工程）を行うことによって多様な２次リグノフェノール誘導体が得られることを示す概念図である。
【図３】（ａ）工程及び１回の（ｂ）工程を実施する本発明の一方法の工程フローを示す図である。
【図４】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収率のグラフを示す図である。
【図５】１次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である。
【図６】実施例において得られた２次リグノフェノール誘導体におけるｐ−クレゾールの導入量を示す図である（計算式（２）による算出に基く）。
【図７】実施例において得られた２次リグノフェノール誘導体におけるｐ−クレゾールの導入量を示す図である（計算式（３）による算出に基く）。
【図８】実施例において得られた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図である。
【図９】実施例において得られた２次リグノフェノール誘導体におけるｐ−クレゾールとｐ−エチルフェノールの導入量を示す図である（計算式（２）による算出に基く）。
【図１０】実施例において得られた２次リグノフェノール誘導体におけるｐ−クレゾールとｐ−エチルフェノールの導入量を示す図である（計算式（３）による算出に基く）。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a technique for forming a phenol derivative of lignin by introducing a phenol derivative into a constituent unit of lignin, which is a component of a plant, and particularly relates to an introduction amount and an introduction ratio when introducing two or more phenol derivatives. And a technology for precisely controlling the structure of a phenol derivative of lignin by easily realizing the control of lignin.
[0002]
[Prior art]
Cell wall constituents, which are the main constituents of plants, that is, composite-containing materials of lignin and cellulose or hemicellulose (hereinafter referred to as lignocellulosic materials) are separated and separated using phenol derivatives and acids. There is a derivatization technique (for example, see Patent Documents 1 and 2).
In such a technique, a technique called phase separation is used to separate lignin from a lignin-cellulose matrix. That is, the lignocellulose-based material is solvated or sorbed with a phenol compound in advance, and then the lignocellulose-based material is brought into contact with an acid to graft the phenol compound onto the lignin and simultaneously with the lignin. Is separated from the matrix with cellulose.
Further, in these methods, there is a technique for improving the separation efficiency (Patent Document 3).
[0003]
[Patent Document 1]
JP-A-2-233701 [Patent Document 2]
JP-A-9-278904 [Patent Document 3]
JP 2001-131201 A
[Problems to be solved by the invention]
At present, the physical properties and the like of the lignin derivative obtained by this method are largely derived from the derived lignocellulosic material, and the introduction efficiency of the phenol compound has not yet been controlled. When two or more phenol compounds are to be introduced, the phenol compounds cannot always be introduced at an intended ratio due to the difference in reactivity of the phenol compounds used.
However, in order to derivatize lignin according to the purpose, it is desired to control the introduction efficiency and the introduction ratio of the phenol compound to a high degree.
Therefore, an object of the present invention is to provide a technique capable of controlling the introduction ratio of a phenol compound to be introduced and the introduction ratio of two or more phenol compounds when a phenol derivative of lignin is obtained from a lignocellulosic material.
[0005]
[Means for Solving the Problems]
The present inventors have made the lignocellulose-based material affinity with a phenol compound, and then added an acid to convert the lignin into a phenol derivative. After the affinity, it was found that a further phenol compound could be introduced by adding an acid, and the present invention was completed.
That is, according to the present invention, the following means are provided.
[0006]
(1) A method for producing a phenol derivative of lignin,
The following steps:
(A) a step of adding an acid to a lignocellulosic material preliminarily affinityd with a first phenolic compound to obtain a primary lignin phenol derivative; Adding an acid to the lignin phenol derivative to obtain the (n + 1) th lignin phenol derivative;
Wherein n is from 1 to N (N is an integer of 1 or more), and a total of N (b) steps are sequentially performed to obtain an (n + 1) -th lignin phenol derivative in each (b) step. .
(2) The method according to (1), wherein in the step (b), N is an integer of 1 or more and 3 or less.
(3) The n-th lignin phenol derivative used in the step (b) is supplied as a composition containing at least a part of a carbohydrate derived from a lignocellulose-based material generated simultaneously in the step (a). ) Or (2). (4) The acid used in at least one of the steps (b) is a different kind of acid from the acid used in the step (a), or is used with a different strength from the acid used in the step (a). The method according to any one of (1) to (3).
(5) The method according to any one of (1) to (4), wherein the acid used in the step (a) is added with a strength capable of swelling the lignin-cellulose matrix.
(6) The method according to any one of (1) to (4), wherein the acid used in the step (a) is added with a strength that does not swell the lignin-cellulose matrix.
(7) The method according to any one of (1) to (6), wherein in any step of obtaining a lignin phenol derivative, ultrasonic waves are irradiated to a lignocellulose-based material or a mixed system containing a phenol derivative and a phenol compound. the method of.
(8) In any step of obtaining a lignin phenol derivative, ultrasonic waves are applied to a lignocellulose-based material or a mixed system containing a lignophenol derivative, a phenol compound and an acid, wherein (1) to (6). The method described in.
(9) The acid in the step (a) is added at least with a strength capable of swelling the lignin-cellulose matrix in the lignocellulose material, and the first phenol compound, the lignocellulose material and the acid are included. The method according to any one of (1) to (4), wherein the mixed system is irradiated with ultrasonic waves.
(10) Mixing the acid in the step (a) with at least a strength that does not swell the lignin-cellulose matrix in the lignocellulose material, and mixing the first phenol derivative, the lignocellulose material and the acid. The method according to any one of (1) to (4), wherein the system is irradiated with ultrasonic waves.
(11) The method according to any one of (1) to (10), wherein the first phenol compound and the second phenol compound contain different types of phenol compounds.
(12) A composition containing a phenol derivative of lignin into which two or more phenol compounds have been introduced, obtained by the method according to any one of (1) to (11).
(13) The composition according to (12), further comprising at least a part of a carbohydrate derived from the lignocellulosic material generated in the step (a).
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
The method for producing the phenol derivative of lignin of the present invention comprises at least
(A) a step of adding an acid to a lignocellulosic material to which a first phenol compound has previously affinityd to obtain a first lignin phenol derivative; and
(B1) a step of adding an acid to the primary lignin phenol derivative to which the second phenol compound has previously affinityd to obtain a secondary lignin phenol derivative. The method is characterized by including a step of obtaining a tertiary or higher lignin phenol derivative. In the following description, a step consisting of one or more steps of derivatization of a primary lignin phenol derivative with a secondary or higher phenol compound is generally referred to as a step (b).
[0008]
The production method of the present invention is characterized in that a conversion treatment (a derivatization step with a phenol compound) is performed in a multistage or sequential manner. According to such a method, various adjustments such as the type of phenol compound used in each step, acid strength, or addition of external energy can be made. As a result, it becomes possible to obtain a lignin phenol derivative in which a phenol compound is introduced at a high introduction ratio or a lignin phenol derivative in which the introduction ratio of a different phenol compound is controlled.
[0009]
Further, the method of the present invention is characterized in that the acid strength is adjusted in any step of obtaining a phenol derivative of lignin.
By adjusting the acid strength, the contact efficiency with the acid changes to change the introduction reaction of the phenol compound, and the amount of the phenol compound introduced can be adjusted.
Furthermore, in the method of the present invention, in any step of obtaining a phenol derivative of lignin, a mixed system containing a phenol compound and a lignocellulosic material and / or a mixed system containing a phenol compound, a lignocellulosic material and an acid It is characterized by irradiating ultrasonic waves.
Irradiation of the ultrasonic wave promotes introduction of the phenol compound and decomposition of the matrix of lignin and cellulose. For this reason, higher introduction control of the phenol compound can be performed by combining the ultrasonic irradiation conditions or the ultrasonic irradiation conditions with other conditions.
Further, ultrasonic irradiation is useful in other aspects. That is, the strength of the acid used in introducing the phenol derivative can be reduced. This makes it easy to control the introduction amount and introduction ratio of the phenol compound.
[0010]
It is known that a lignin phenol derivative having a phenol propane unit of lignin is obtained by introducing a phenol compound at the C1 position of an aryl propane unit of lignin in the phase separation treatment. However, in the phase separation treatment, introduction of a phenol compound was difficult unless swelling of cellulose (carbohydrate) by an acid was achieved. On the other hand, the phase separation conversion treatment in the presence of an acid that can achieve the swelling of cellulose has a very rapid reaction rate, and it is very difficult to control the amount of the phenol compound introduced. That is, the only way to stabilize or control the amount of the phenol compound introduced was to perform a phase separation conversion treatment for a sufficient time and to introduce the phenol compound at the C1 position where the phenol compound can be introduced by the treatment. . As a result, it has been difficult to envisage further introduction of the phenol compound in multiple stages. It was also difficult to predict the possibility of introducing an additional phenol compound. Therefore, even after the phase separation treatment, the introduction of a phenol compound at the C1 position was a finding that could not be predicted. The present invention has been made based on such findings.
[0011]
In addition, under such circumstances, when introducing a plurality of phenol compounds, the amount and ratio of introduction were adjusted by selecting the respective reactivity and compounding ratio. Below, control by these adjustments was very difficult. According to another aspect of the present invention, it is possible to control the amount of a phenol compound to be introduced in the first-stage phase separation conversion treatment by adjusting the strength of the acid and further combining the irradiation with ultrasonic waves and the like. did. In particular, a low introduction amount of the phenol compound, which has been difficult in the first stage treatment, can be achieved. In addition, this makes it possible to increase the diversity of the conversion processing in the second and subsequent stages, and at the same time, control the introduction of the phenol compound with high accuracy.
[0012]
Further, at least in the first stage of the phenol derivatization step of the present invention and in the subsequent derivatization step of the phenol compound, a method of separating a lignin phenol derivative together with a carbohydrate derived from a lignocellulosic material is employed, whereby the resulting lignin is obtained. The phenol derivative is at least partially in a complex state with the carbohydrate. Therefore, in such a composite composition, the lignin phenol derivative can stably maintain the active C1 position, that is, the C1 position where the phenol compound is not introduced. Therefore, according to the composite composition, a further phenol derivatization step and another derivatization step (such as a crosslinkable group introduction treatment, an alkali treatment, and a hydroxyl group protection treatment) using the active C1 can be easily performed. There is provided a material composition that can be used. In addition, since the said composite composition has plasticity, it has already been discovered by the present inventors that it can be used for various uses as a molding material or the like based on the plasticity (see JP-A-2001-342353). . Therefore, according to the composite composition, there is provided a material composition (thermoplastic composition) that retains the active C1 position and can be used for a long time and in multiple stages.
[0013]
In addition, the primary lignin phenol derivative (hereinafter, also referred to as a primary lignophenol derivative) is obtained from a lignocellulose-based material, and the first phenol compound is grafted to the C1 position of the arylpropane unit of lignin. The term refers to a lignin derivative having a 1,1-bis (aryl) propane unit (hereinafter, also referred to as a first unit). In addition, a secondary lignophenol derivative refers to a 1,1-bis (aryl) propane unit (hereinafter, referred to as a “lignin phenol derivative”) in which a second phenol compound is grafted at the C1 position of an arylpropane unit of lignin in addition to the first unit. Lignin derivative). Hereinafter, the higher-order lignophenol derivatives after the tertiary lignophenol derivative are all obtained by grafting a further phenol compound to the C1-position of the arylpropane unit in addition to the first unit and the second unit. Lignin derivative having a, 1-bis (aryl) propane unit.
[0014]
Hereinafter, general and general properties of a primary lignophenol derivative obtained from a lignocellulosic material will be described. However, this is not intended to limit the primary or secondary or higher lignophenol derivative in the present invention to those having the following properties.
(1) The weight average molecular weight is about 2,000 to 20,000.
(2) It has almost no conjugated system in the molecule and its color tone is extremely light. Typically, it is a pale pinkish white powder.
(3) It has a solid-liquid phase transition point at about 170 ° C derived from softwood and at about 130 ° C derived from hardwood.
(4) It is easily dissolved in methanol, ethanol, acetone, dioxane, pyridine, tetrahydrofuran, dimethylformamide and the like.
[0015]
Hereinafter, embodiments of the present invention will be described in detail.
(Lignocellulosic material)
The "lignocellulosic 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 component of a plant cell wall. For example, woody materials, various materials that are mainly wood, such as wood flour and chips, as well as agricultural waste and industrial waste associated with wood resources such as waste materials, offcuts, and used paper can be mentioned. As the type of wood to be used, any type of wood, such as conifer or hardwood, can be used. In addition, all or part of various herbaceous plants such as kenaf, rice, sugar cane, and corn, and agricultural and industrial wastes such as bagasse related thereto can be used.
[0016]
(Primary or higher 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 at the C1 position of a lignin arylpropane unit (C9 unit) by a CC bond. . It is a kind of polyphenol.
The lignophenol derivative is a mixture of a lignin-derived polymer obtained by reacting and separating 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 ( It is typically a lignocellulosic material.) And reaction conditions.
[0017]
The primary lignophenol derivative can be usually obtained by contacting a lignin-containing material, preferably a lignocellulosic material, to which a predetermined phenol derivative has affinity, with an acid. In addition, about the more general description about a lignophenol derivative and its manufacturing process, it already describes Unexamined-Japanese-Patent No. 2-23701, Unexamined-Japanese-Patent No. 9-278904, and WO99 / 14223, 2001-64494, These are described in 2001-261839, 2001-131201 and 2001-342353 (the contents of these patent documents are all incorporated herein by reference).
[0018]
In this production process, the lignocellulosic material was selectively brought into contact with an acid while maintaining the lignocellulose-based material on the phenol derivative phase side, the decomposed cellulose was distributed to the acid side, and the phenol derivative was introduced through contact with the acid. This is a process that simultaneously achieves structural conversion and separation of lignin, which distributes lignin to the phenol derivative side. In constructing such a reaction system, it is particularly preferable that the lignocellulose-based material is previously made compatible with a phenol derivative. Here, the affinity is used in the meaning of solvation, permeation, absorption and adsorption (also called 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 form a lignophenol derivative. This is a method that can simultaneously separate cellulose and a lignophenol derivative.
According to this method, a lignophenol derivative having a 1,1-bis (aryl) propane unit is obtained in which the phenol derivative is grafted to the C1 position of the lignin arylpropane unit at the ortho or para position of the phenol derivative used. be able to. Note that, in the obtained lignophenol derivative, an arylpropane unit to which no phenol is grafted usually remains.
[0019]
Various methods can be exemplified as a method for obtaining a lignophenol derivative from a lignocellulosic material based on the above reaction, ie, the step (a) for obtaining a primary lignophenol derivative. The step (b) of obtaining a lignophenol derivative having a higher order than the second order is performed except that the lignocellulose-based material exemplified below is used as the lignophenol derivative obtained in the preceding step or a composition containing the same. Configured by common operations.
Step (b) does not particularly limit the number of steps. Usually, it is a high-order lignophenol derivative which is about 1 to 3 times, that is, a secondary lignophenol derivative to a quaternary lignophenol derivative. In addition, if it is a secondary lignophenol derivative into which at least two kinds of phenol compounds have been introduced, a lignophenol derivative having a considerable range of diversity can be obtained.
[0020]
In any of the modes for obtaining a lignophenol derivative, a step in which the lignocellulose-based material (or the lignophenol derivative) is affinityd with the phenol compound, and an acid is added to the lignocellulose-based material (or the lignophenol derivative) previously affinityd with the phenol compound. Introducing a phenol compound into lignin in a reaction system obtained by the addition.
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 method for separating the obtained lignophenol derivative.
Although four typical methods are illustrated below, it is not intended that the step (a) or (b) be limited to these four methods.
[0021]
The first method is a method described in JP-A-2-233701. This method includes a single affinity step. The first-stage affinity step is a step of infiltrating a liquid phenol derivative into a lignocellulosic material such as wood flour and solvating lignin with the phenol derivative. Note that the phenol derivative can be diluted with an inert solvent such as benzene before use.
Next, the introduction step will be described. The introduction step is a step of adding and mixing a concentrated acid (as described above, for example, 72% sulfuric acid) to the lignocellulosic material, hydrolyzing the cellulose component, and introducing a phenol derivative into lignin.
In this step, the phenol derivative solvated with lignin and the concentrated acid in which the cellulose component is dissolved form a two-phase separation system. Lignin solvated by the phenol derivative is contacted with the acid only at the interface where the phenol derivative phase contacts the concentrated acid phase, and a reaction occurs. That is, the cation at the side chain C1 position (benzyl position), which is a high reaction site of the lignin basic structural unit generated by interfacial contact with an acid, is attacked by the phenol derivative. As a result, a phenol derivative is introduced into the C1 position via a CC bond, and the molecular weight is reduced by cleavage of the benzyl aryl ether bond. As a result, lignin is reduced in molecular weight, 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 generated in the phenol derivative phase. From this phenol derivative phase, a lignophenol derivative is extracted. The lignophenol derivative is obtained as an aggregate of low molecular weight lignins in which the benzyl aryl ether bond in the lignin has been cleaved to reduce the molecular weight. It is known that some phenol derivatives are introduced into the benzyl position via the phenolic hydroxyl group.
FIG. 1 shows that various lignophenol derivatives can be obtained by subjecting natural lignin having an arylpropane unit to a phase separation treatment.
[0022]
The 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 portion is removed by centrifugation or the like, and the acetone-soluble portion is concentrated. The acetone-soluble portion is added dropwise to a large excess of ethyl ether, and the precipitate 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 portion by distillation under reduced pressure.
[0023]
The second and third methods include a two-step affinity process. In the two-stage affinity step, a solvent (eg, ethanol or acetone) in which a solid or liquid phenol derivative (eg, p-cresol or 2,4-dimethylphenol) is dissolved is penetrated into the lignocellulosic material. After that, the solvent is distilled off.
Next, a concentrated acid is added to the lignocellulosic material to dissolve the cellulose component (corresponding to the above-mentioned introduction step). As a result, as in the first method, the lignin solvated with the phenol derivative causes the cation at the high reaction site (side chain C1 position) of the lignin generated by contact with the concentrated acid to be attacked by the phenol derivative, and Derivatives are introduced. Further, 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 into which the phenol derivative has been introduced is extracted with the liquid phenol derivative. The extraction of the lignophenol derivative from the liquid phenol derivative phase can be performed in the same manner as in the first method (this is referred to as a second method). Alternatively, the entire reaction solution after the concentrated acid treatment is poured into excess water, the insoluble fraction is collected by centrifugation, deacidified, and dried. Acetone or alcohol is added to the dried product to extract a lignophenol derivative. Further, similarly to the first method, the soluble fraction is dropped into excess ethyl ether or the like to obtain a lignophenol derivative as an insoluble fraction (this is referred to as a third method). The specific examples of the method for preparing the lignophenol derivative have been described above. However, the present invention is not limited thereto, and the lignophenol derivative can also be prepared by appropriately improving the method.
[0024]
A fourth method is a method described in JP-A-2001-131201, in which a mixture containing a lignocellulose-based material, a phenol derivative, and an acid (also referred to as a reaction system in this specification) is mixed with benzene, xylene, After mixing with an inert low-boiling-point hydrophobic organic solvent selected from toluene, hexane or a mixture thereof, the mixture is separated into three layers by centrifugation, and the lignophenol derivative fraction is separated into a second layer which is aggregated in a band. How 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 fractionated lignophenol derivative can be distributed to an ether-insoluble fraction and then fractionated to an acetone-soluble fraction as described in the first and second methods, or can be fractionated to an acetone-soluble fraction. As described above, it can be added to excess water to obtain a water-insoluble fraction. Preferably, as in the above third method, after fractionating into a water-insoluble fraction, the acid is washed off and finally a lignophenol derivative is obtained in a fraction that is dissolved in acetone or the like.
[0025]
The method of the present invention comprises one or more steps (b) in addition to the conventional step (a). The lignophenol to be grafted with the phenol compound to be supplied after the step (b) is provided. Derivatives are not necessarily limited to those separated as lignophenol derivatives. As is clear from the methods already exemplified, the fraction (composition) at the stage before finally separating the lignophenol derivative may be used. For example, in the above-mentioned second to fourth methods, the reaction system after the acid reaction is collected as a fraction (composition) containing a lignophenol derivative and a carbohydrate derived from a lignocellulose-based material obtained by putting the reaction system into a large amount of water. May be used. Further, a composition in which such a carbohydrate is separately added without being derived from the reaction system may be used. In the following description, the term "lignophenol derivative" supplied in the step (b) means a composition containing carbohydrate derived from a lignocellulose-based material or a composition containing other components in addition to the lignophenol derivative alone. Can be
[0026]
In the method of the present invention, the phenolic compound used for grafting to the C1 position of the arylpropane unit of lignin can be changed between step (a) and step (b). Thereby, a lignin derivative having different units to which two or more phenol compounds are grafted can be easily obtained. By using different phenol compounds in different steps, the introduction rate of these phenol compounds can be controlled respectively. The phenol compound may be partially or completely identical in some or all of these steps.
[0027]
FIG. 2 shows a conceptual diagram in the case where different phenol compounds are sequentially introduced in two stages. In this figure, p-cresol is used as the first phenol compound and p-ethylphenol is used as the second phenol compound.
The example in the upper part of FIG. 2 shows the step of introducing the first phenol compound at a low introduction rate and introducing the second phenol compound different from the first phenol compound at a relatively high introduction rate.
The middle example in FIG. 2 shows a step of introducing the first phenol compound at an introduction rate of about half and introducing the second phenol compound at the same introduction rate.
The example in the lower part of FIG. 2 shows a step of introducing the first phenol compound at a high introduction rate and introducing the second phenol compound at a low introduction rate.
[0028]
FIG. 3 shows a step of an embodiment of the method of the present invention in which the step (a) is performed by the third method and the step (b) is performed by the first to fourth methods in total. 4 shows a flow. In this flow, the primary lignophenol derivative is supplied to the step (b) as a composition containing a carbohydrate derived from a lignocellulose-based material.
[0029]
Further, in the method of the present invention, the type and strength of the acid used in each of the steps (a) and (b) can be changed. This makes it possible to control the degree of decomposition and separation of carbohydrates and the rate of introduction of phenol compounds. In particular, when different phenol compounds are used between steps, the introduction rate of different phenol compounds can be easily controlled.
Hereinafter, the phenol compound and the acid will be described.
[0030]
(Phenol compound)
In step (a) of the method of the present invention, as a lignophenol compound used for obtaining a higher-order lignophenol derivative, a monovalent phenol compound, a divalent phenol compound, a trivalent phenol compound, or the like is used. Can be. Specific examples of the monovalent phenol compound include a phenol which may have one or more substituents, a naphthol which may have one or more substituents, and a phenol which may have one or more substituents. Examples include good anthrol and one or more anthroquinone ols which may have a substituent.
Specific examples of the divalent phenol compound include catechol optionally having one or more substituents, resorcinol optionally having one or more substituents, and one or more substituents. Good hydroquinone and the like.
Specific examples of the trivalent phenol compound include pyrogallol which may have one or more substituents.
In the present invention, one or more of a monovalent phenol compound, a divalent phenol compound and a trivalent phenol compound can be used, but a monovalent phenol is preferably used.
The phenol compound in each step can be used alone or in combination of two or more.
[0031]
The type of the substituent that the monovalent to trivalent phenol compound may have is not particularly limited, and may have any substituent. And the like, for example, a lower alkyl group-containing substituent having 1 to 4 carbon atoms, preferably 1 to 3 carbon atoms. In consideration of the introduction ratio, 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.
[0032]
These phenol compounds are introduced into the arylpropane unit by bonding the carbon atom at the ortho or para position to the phenolic hydroxyl group to the carbon at the C1 position of the arylpropane unit of lignin. Therefore, in order to secure an introduction site, it is preferable that at least one of the ortho position and the para position has no substituent.
[0033]
From the above, in the present invention, in addition to the unsubstituted phenol compound, it is possible to appropriately select and use one or more kinds of various substituted phenol compounds having at least one unsubstituted ortho or para position. it can.
[0034]
The introduction frequency of the phenol compound varies depending on the presence, position, size, and the like of the substituent of the phenol compound to be introduced. Therefore, the frequency of introduction can be adjusted by selecting a phenol compound. In particular, the frequency of introduction can be easily adjusted by steric hindrance caused by the size of the substituent. When it is intended to control the introduction position or the like using a substituent, if a lower alkyl group is used as the substituent, the introduction frequency can be easily adjusted depending on the number of carbon atoms and the branched form. When the substituent is a methyl group, the introduction position can be controlled while maintaining a high introduction frequency.
[0035]
In the present invention, since the phenol compound is introduced in two or more steps, the type and combination of the phenol compound used in the step (a) and the step (b) are changed so that the introduction position of the phenol compound due to the substituent and the like can be improved. It is possible to accurately control the introduction rate. Further, as described later, by controlling the reaction conditions, that is, by controlling the strength of the acid, the stirring intensity, or the irradiation conditions of the ultrasonic wave, the introduction amount and the ratio of the phenol compound can be controlled for each step. . Therefore, the introduction ratio of a phenol compound having a difference in introduction reactivity can be more easily controlled. As a result, for example, crosslinking reactivity and structural control during crosslinking can be realized with high accuracy.
Even when the same phenol compound is introduced in two or more steps, it is effective in that a high introduction rate can be easily obtained.
[0036]
Specific examples of the phenol compound used include p-cresol, p-ethylphenol, 2,6-dimethylphenol, 2,4-dimethylphenol, 2-methoxyphenol (Guaiacol), 2,6-dimethoxyphenol, Catechol, resorcinol, homocatechol, pyrogallol, phloroglucinol and the like.
[0037]
(acid)
The acid used in the steps (a) and (b) is not particularly limited. For example, sulfuric acid, hydrochloric acid, phosphoric acid, p-toluenesulfonic acid, trifluoroacetic acid, trichloroacetic acid, formic acid and the like can be mentioned. Preferably, the acid is strong enough to swell the lignin-cellulose matrix by nature or depending on the concentration. Here, an object to be swollen with an acid is mainly cellulose. Examples of the acid having such a strength include sulfuric acid of 65% by weight or more, phosphoric acid of 85% by weight or more, hydrochloric acid of 35% by weight or more, 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 water-soluble polysaccharides, oligosaccharides, and monosaccharides derived from cellulose and hemicellulose, it is preferable to use sulfuric acid, which suppresses the action on cellulose and recovers it in a form that retains its higher-order structure to some extent. It is preferable to use an acid having a low acid strength such as phosphoric acid.
[0038]
In the present invention, in particular, in each of the steps (a) and (b), the type of the acid and the strength of the acid can be changed. By adjusting the conditions related to the acid, it is possible to adjust the degree of decomposition and separation of the carbohydrate, and thus the introduction rate of the phenol compound. For example, when an acid having a low strength is used, the introduction rate of a phenol compound decreases, and when an acid having a high strength is used, the introduction rate of a phenol compound can be improved. In the step (a), that is, in the step of producing and separating the primary lignophenol derivative from the lignocellulosic material, the use of an acid with a strong strength promotes the decomposition and separation of cellulose, and the grafting of the phenol compound is promoted. In order to promote this, a primary lignophenol derivative to which the first phenol compound is grafted at a high introduction rate can be obtained. In addition, when the carbohydrate derived from the lignocellulose-based material is included in the lignophenol derivative fraction according to the third method or the like, the carbohydrate content is significantly reduced. In addition, here, it is preferable that the strong strength is added so that the lignin-cellulose matrix can swell, and the acids exemplified above can be preferably used. In addition, while adopting a strong acid strength, a mixture system (reaction system) containing the lignocellulose-based material, the first phenol compound and the acid is subjected to ultrasonic irradiation, which will be described later, to further reduce the introduction rate of the phenol compound. Can be improved.
[0039]
On the other hand, in the step (a), that is, in the step of producing and separating the primary lignophenol derivative from the lignocellulose-based material, the use of an acid with a low strength delays the decomposition and separation of the cellulose and causes the grafting of the phenol compound. Because of the delay, a primary lignophenol derivative in which the first phenol compound is grafted at a low introduction rate can be obtained. Further, when the carbohydrate derived from the lignocellulose-based material is contained in the lignophenol derivative fraction according to the third method or the like, the carbohydrate content is significantly increased. Here, the weak acid strength preferably means that the lignin-cellulose matrix is added at such a strength that it does not swell. Here, the acid that does not swell the lignin-cellulose matrix can 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. Preferred 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 at the time of the affinity prior to the reaction step with the acid, the acid strength may be lower. In addition, while adopting a weak acid strength, the introduction rate of the phenol compound is increased by performing ultrasonic irradiation described later on a mixed system (reaction system) containing the lignocellulosic material, the first phenol compound and the acid. Can be improved. According to the combination, since a low acid strength is employed, the introduction rate of the phenol compound can be easily adjusted by the intensity of the ultrasonic irradiation.
[0040]
In the above example, the case where the strength of the acid or the ultrasonic wave is used in the step (a) has been described, but the acid strength or the ultrasonic irradiation is also used in the step (b), and the second and subsequent phenol compounds are used. Of carbohydrates and the rate of carbohydrate separation can be controlled.
[0041]
(Ultrasonic irradiation)
In the steps (a) and (b) of the present invention, a lignocellulose-based material or a mixed system of a lignophenol derivative obtained in the previous stage and a phenol compound (a mixed system at the time of affinity), or these two components. In addition, by applying ultrasonic irradiation to a mixed system with an acid (a mixed system at the time of reaction with an acid), the affinity and the reaction can be promoted. Therefore, depending on the presence or absence of ultrasonic irradiation on these mixed systems, the introduction rate of the phenol compound and the degree of carbohydrate separation and decomposition can be adjusted.
[0042]
(Ultrasonic irradiation during affinity with phenolic compounds)
In the method of the present invention, a reaction with an acid can be promoted by irradiating the lignocellulose-based material and / or the phenol derivative with ultrasonic waves when the lignocellulose-based material has affinity for the phenol compound. Preferably, in a state where the lignocellulose-based material and the phenol derivative are simultaneously present (mixed system), both are irradiated with ultrasonic waves. By such ultrasonic irradiation, the phenol compound can be efficiently and sufficiently penetrated into the lignocellulose-based material, and a state in which both are sufficiently compatible can be easily and promptly obtained. As a result, in the subsequent step of introducing a phenol compound into lignin, the phenol compound can be efficiently introduced into lignin. Therefore, the introduction rate and ratio of the phenol compound can be controlled by the presence or absence and intensity of ultrasonic irradiation at the time of affinity.
[0043]
The ultrasonic irradiation at the time of the affinity can be applied to any of the affinity exemplified in the first method and the second method described above. In the first method, it is possible to irradiate ultrasonic waves in a state where a liquid phenol derivative is infiltrated into a lignocellulose material or a state where a lignocellulose material or a lignophenol derivative is immersed in a phenol derivative. it can. 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. Ultrasonic waves can be irradiated in a state where the organic solvent is distilled off, preferably before the organic solvent is distilled off. The organic solvent can be distilled off while irradiating ultrasonic waves.
[0044]
The voltage and frequency of the ultrasonic wave applied to the mixed system at the time of affinity are not particularly limited, provided that the irradiation is performed under conditions that can improve the affinity between the phenol compound and the lignocellulose-based material or the lignophenol derivative. Good. If the voltage and frequency of the ultrasonic generator that can be used normally (power of about 100 W to about 1500 W, frequency of about 20 kHz to about 40 kHz), the above effects can be obtained by irradiation for several tens of seconds to several tens of minutes.
The irradiation form of the ultrasonic wave is not particularly limited, but the oscillator may be invaded into a liquid phenol derivative, or the oscillator may be arranged in a water tank or the like in which a container containing the liquid phenol derivative is immersed. Irradiation may be performed.
In addition, mechanical stirring may be separately accompanied with the ultrasonic irradiation. The ultrasonic irradiation is not necessarily required to be continuous, but may be intermittent. Further, it is not necessary to use the entire time during the affinity, and it may be used only during a part of the affinity.
[0045]
(Ultrasonic irradiation during reaction with acid)
Further, as described above, in the present invention, it is also possible to irradiate ultrasonic waves to a reaction system obtained by adding an acid to a lignocellulosic material to which affinity has been previously applied. When irradiating the reaction system with ultrasonic waves, it is preferable to irradiate ultrasonic waves to almost the entire area. Alternatively, it is also preferable to add another stirring and mixing means, specifically, a mechanical stirring means using a stirrer or a stirring blade, or a stirring means using a jet or the like.
[0046]
In the step of introducing a phenol compound into lignin, irradiation with ultrasonic waves can promote decompositing of a lignin-cellulose matrix in a lignocellulosic material. The promotion of decomplexing also has the aspect that the probability of contact between lignin and an acid is improved, and a high introduction rate of a phenol derivative can be obtained at an early stage. For example, for example, the introduction rate obtained under the same conditions except for using mechanical stirring is achieved in about 1/4 to about half time by performing an introduction step involving moderate ultrasonic irradiation. be able to. In addition, both the introduction rate of the phenol compound and the production amount of the lignophenol derivative can be increased by ultrasonic irradiation. In addition, when ultrasonic irradiation is performed on the affinity mixed system, since the lignocellulose-based material or the lignophenol derivative and the phenol compound have a good affinity, the introduction is more rapid, and Thereafter, the mixture is stably distributed to the phenol compound phase, and the separation from the cellulose can be facilitated.
Therefore, the introduction rate and ratio of the phenol compound can be adjusted by adjusting the intensity of the ultrasonic irradiation to the reaction system.
[0047]
In the step of introducing the phenol compound into the lignin, the contact probability between the lignocellulose-based material or the lignophenol derivative and the acid is improved by irradiating ultrasonic waves, and the introduction step can be performed efficiently. In addition, for example, the introduction rate obtained under the same conditions except for using mechanical stirring is achieved in about 1/4 to about half the time by performing an introduction step involving moderate ultrasonic irradiation. be able to. In addition, both the introduction rate of the phenol compound and the production amount of the lignophenol derivative can be increased by ultrasonic irradiation.
In addition, when ultrasonic irradiation is performed on the affinity mixed system, since the lignocellulose-based material and the phenol derivative have a good affinity, the introduction is more rapid, and the introduction is stable even after the introduction. To the phenol derivative phase to facilitate separation from cellulose.
[0048]
The voltage and frequency of ultrasonic irradiation on the reaction system are not particularly limited, as in the affinity step. The contact probability between the phenol derivative and the lignocellulose-based material can be several tens of seconds to several tens of seconds if the voltage and frequency of the ultrasonic generator that can be used normally (power of about 100 W to about 1500 W, frequency of about 20 kHz to about 40 kHz). Irradiation for about a minute can sufficiently improve.
The irradiation form of the ultrasonic wave is not particularly limited, but may be a state in which the oscillator is penetrated into the liquid phenol derivative, or the oscillator is arranged outside the container containing the liquid phenol derivative and irradiated. You may. Further, similarly to the affinity step, mechanical stirring can be separately added with the ultrasonic irradiation, and the irradiation may be continuous or intermittent. In addition, it is not necessary to use it for the entire time of the introduction step, and it may be used only for a part of the introduction step.
[0049]
(Lignophenol derivative composition)
The water-insoluble fraction (water-insoluble fraction composition) obtained by pouring the acidic reaction mixture obtained in the step (b) into water is a lignocellulose-based material in addition to a secondary or higher-order lignophenol derivative. It contains carbohydrates such as water-insoluble cellulose derived from it and can be said to be a lignophenol derivative-containing composition. In the composition, at least a part of the lignophenol derivative forms a complex with a carbohydrate (cellulose) derived from a lignocellulose-based material. Further, the composition has thermoplasticity.
As described above, the combination of the lignophenol derivative and the carbohydrate such as cellulose in the water-insoluble fraction can be adjusted by a combination of the ultrasonic treatment and the acid strength. At the same time, the introduction ratio and introduction ratio of the phenol compound can be adjusted.
Therefore, it is possible to obtain a lignophenol derivative-containing composition containing a lignophenol derivative in which a desired phenol compound is introduced at a highly controlled introduction rate or ratio, and where necessary, the carbohydrate content ratio is adjusted. .
In addition, in the said composition, since the remaining active C1 position is stably hold | maintained, it is preferable as a material composition used for the following phenol compound derivatization process or another derivatization process. Further, a lignocellulose-based composite which is preferable in that a molded article or the like obtained by imparting a shape to the composition can hold the lignophenol derivative in a state suitable for the next conversion is provided.
[0050]
The secondary or higher secondary lignophenol derivative thus obtained is subjected to a hydroxyl group protection treatment such as an acylation protection treatment, the introduction of a crosslinkable group such as a hydroxymethyl group, or an alkali accompanied by the formation of a coumaran unit. Various other derivatization steps such as treatment can be performed.
[0051]
【Example】
Hereinafter, the present invention will be described with reference to specific examples. The present invention is not limited to the following examples.
(Example 1)
Preparation of Primary Lignophenol Derivatives (1) Affinity Step-Sorption of Phenol Derivatives Pinewood pine (Pseudosuga menziessi, hereinafter referred to as Douglas fir) is pulverized by an ultracentrifugal mill ZM100 manufactured by Retsh, and then IIDA. An 80 mesh pass wood powder was obtained by sifting through an 80 mesh manufactured by Seisakusho.
This wood flour was extracted with a solution of ethanol: benzene = 1: 2 (V / V) using a Soxhlet extractor for 48 hours. After extraction, the wood flour was spread in a stainless steel vat, and the solvent was completely distilled off in the fume hood. Further, it was dried at 105 ° C. for 24 hours with a blow dryer to obtain absolutely dry wood flour.
[0052]
Wood flour equivalent to 3 g of absolutely dried wood flour was placed in a 100 ml separable flask, and about 30 ml of an acetone solution of p-cresol, a phenol compound, was added (containing ₉ mol units of lignin C containing a phenol compound equivalent to 3 mol times). Next, the wood flour was slightly agitated with a stirring wing to remove air bubbles, and the beaker was covered with aluminum foil and parafilm and allowed to stand for about 24 hours. After standing, acetone was completely distilled off by vigorous stirring in a fume hood. The sample from which acetone was distilled off was used as phenol compound sorptive wood flour.
[0053]
(2) Phenol compound introduction step-Sulfuric acid treatment 60 ml of each of 60 wt%, 65 wt%, and 72 wt% sulfuric acid aqueous solution, which has been previously adjusted to 30 ° C., is added to the phenol compound sorptive wood powder that has been affinity-treated in (1). In addition, ultrasonic waves are irradiated by an ultrasonic generator (BRANSON SONIFIER 450D, 20 kHz, output 180 W) while stirring at 500 rpm for a predetermined time from a stirrer, and the introduction process is performed in three types of processing time of 5 minutes, 10 minutes, and 20 minutes. Was done. After the completion of the process, each content was poured into a large excess of water (about 600 ml, under forced stirring) in an 11-volume Erlenmeyer flask, the sulfuric acid concentration was reduced to 10% or less, and the mixture was stirred for about 1 hour. In addition, except not irradiating an ultrasonic wave, it carried out similarly to the above and used it as each control.
[0054]
(3) Deacidification treatment Transfer the contents of the Erlenmeyer flask to a centrifuge tube (made of polypropylene) with deionized water, and centrifuge [8800 rpm (10560 G), 20 min, 5 ° C] to obtain a water-soluble fraction (including suspended matter). Separated into water-insoluble section. After separation, the soluble fraction (including suspended matter) in the centrifuge tube is taken out into a 51 volume Erlenmeyer flask with a Komagome pipette, and the water-insoluble fraction is further added with deionized water, stirred and centrifuged, and the unreacted phenol derivative And the acid were removed as a soluble fraction. After the soluble fraction in a 5 l Erlenmeyer flask was allowed to stand for about 1 day, the supernatant was taken in a beaker with a suction filter bell so as not to disturb the precipitate, and filtered through a glass fiber filter paper whose constant weight had been determined in advance. After that, the constant weight of the suspended matter remaining on the filter paper was measured.
[0055]
(4) Drying of the water-insoluble section The insoluble section after the 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 on phosphorus pentoxide. After drying under reduced pressure, the constant weight was determined and the yield based on the initial wood flour was measured.
[0056]
(5) Observation of the reaction system during ultrasonic irradiation in the introduction step [Ultrasonic treatment using 60 wt% 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 flour particles, wood flour particles were confirmed even after the sulfuric acid treatment. In the ultrasonically treated sample, similar particles were confirmed after the reaction. In addition, when the sulfuric acid aqueous solution was added, no increase in the viscosity of the sample could be confirmed regardless of the presence or absence of ultrasonic irradiation. These results indicate that a 60% aqueous sulfuric acid solution cannot cause sufficient swelling of the plant cell wall. After the aqueous dispersion, the color of the treated sample tended to become red as the treatment time changed to 5 minutes, 10 minutes, and 20 minutes in each of the control sample and the ultrasonically treated sample. In addition, 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 coloring components in wood.
[0057]
[Ultrasonic treatment using 65 wt% 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 green in about 3 to 4 minutes. In the ultrasonically treated sample, wood powder particles could not be confirmed in about 5 to 6 minutes, but in the control sample, wood powder particles could not be confirmed in the treatment time of 10 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 the 60 wt% sulfuric acid treatment, the sonicated sample was darker than the control sample. In the control sample, a white precipitate section was confirmed when the insoluble section was recovered. This white section was similarly confirmed in the sample subjected to sonication for 5 minutes and 10 minutes, but was not confirmed in the sonication performed for 20 minutes. This white section is considered to be a result of aggregation of the under-hydrolyzed carbohydrate section in the plant cell wall, and the white section of the carbohydrate was not confirmed in the ultrasonically treated sample for 20 minutes. Has been shown to promote hydrolysis. The redness of the phase-separated sample is derived from the degree of conversion of lignin molecules, which are coloring components in wood, as in the case of the 60 wt% sulfuric acid treatment.
[0058]
[Ultrasonic treatment using 72 wt% sulfuric acid aqueous solution]
In the treatment using the 72 wt% sulfuric acid aqueous solution, the color changed to a rather dark green immediately after the addition of the sulfuric acid aqueous solution, unlike the case where the 60% sulfuric acid aqueous solution or the 65% sulfuric acid aqueous solution was added. Thereafter, the color was slightly darkened in about 4 to 5 minutes. Wood powder particles could not be confirmed in about 5 to 6 minutes in the sonicated sample, and could not be confirmed in 9 to 11 minutes in the control sample. After dispersion in water, the color of the sample subjected to phase separation was green. The color of the sonicated sample hardly changed even when the processing time was increased to 5 minutes, 10 minutes, and 20 minutes. However, in the control sample, as the processing time increased to 5 minutes, 10 minutes, and 20 minutes. It turned green. In the control sample, when the treatment time was 5 minutes and 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 ultrasonically treated sample, the white section observed during the 65 wt% sulfuric acid treatment was not confirmed. This indicated that the 72 wt% sulfuric acid aqueous solution had the ability to sufficiently hydrolyze carbohydrates, and that the rate of carbohydrate hydrolysis was accelerated by ultrasonic energy.
[0059]
It should be noted that the change in color after the addition of the lignin acid is a coniferyl aldehyde present at the end of the lignin, which is merely an inference and does not limit the present invention. When one molecule of p-cresol is introduced, it is thought to be caused by the extension of the conjugated system in the molecule. Furthermore, the color changes to dark green with time because p-cresol is sufficiently introduced and various types of conjugated systems are generated, so that the light absorption wavelength can be expanded. It is thought to be caused by The decrease in the brightness of the sonicated sample is considered to be due to the hydrolysis of the carbohydrate, which is a white component, and the dissolution of the carbohydrate in the solvent due to the low-polymerized oligomer-level sugar. . It is considered that the difference in the color of the synthesized phase-separated sample was caused by the difference in the degree of oxidation and the degree of dispersion of the converted lignin molecules.
[0060]
(6) Yield of water-insoluble fraction (lignophenol derivative-containing composition) FIG. 4 shows a graph of the yield of the lignophenol derivative-containing composition per absolutely 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. It is considered that the decrease in the yield in the 60% sulfuric acid treatment was caused by the fact that the hemicellulose fraction and the amorphous fraction of cellulose in the wood having low acid resistance were hydrolyzed by the acid and flowed out to the aqueous phase.
[0061]
In the case of using a 65 wt% sulfuric acid aqueous solution, the yield of the control sample was almost the same as that of the 60 wt% sulfuric acid treatment, that is, the yield decreased (ie, decreased gradually). On the other hand, the ultrasonically treated sample showed a significant decrease in yield. For the control sample, the aqueous solution of 65% by weight sulfuric acid can swell the crystalline region of cellulose and the hydrolysis of the cellulose section is insufficient, but the outflow of the recellulose section proceeds more than in the case of using 60% by weight sulfuric acid. Is considered to be the cause. The significant decrease in yield in the sonicated sample is due to the promotion of cell wall swelling and hydrolysis by 65 wt% sulfuric acid, which is enhanced by ultrasonic energy and the contact between the carbohydrate section and the acid is increased, thereby promoting the hydrolysis of the carbohydrate section. It is thought that it is caused by having been done.
[0062]
When a 72 wt% sulfuric acid aqueous solution was used, the yield of the control sample showed almost the same tendency as the yield of the ultrasonically irradiated 65 wt% sulfuric acid treated sample. This indicates that the 72% aqueous sulfuric acid solution is capable of causing cell wall swelling and more fully hydrolyzing the carbohydrate fraction. On the other hand, in the case of the ultrasonically treated sample, the yield was not significantly changed even when the treatment time was increased to 5 minutes, 10 minutes, and 20 minutes. It is presumed that the decomposition rate was accelerated and the reaction reached equilibrium in about 5 minutes.
[0063]
(Example 2)
Measurement of Lignin Content in Primary Lignophenol Derivative Composition About 200 mg of each composition of Example 1, which has been sufficiently dried, is precisely weighed in a 10-ml sample tube, and 3 ml of a 72% aqueous sulfuric acid solution is added little by little to a glass. The mixture was added while kneading with a stick, and reacted for 4 hours in a water bath at 20 ° C. with sufficient stirring so that the reaction progressed uniformly. After the reaction, the mixture was quantitatively transferred to a 200 ml Erlenmeyer flask marked 115 ml in advance, and deionized water was added to dilute the sulfuric acid concentration to 3%. The diluted processed product was heated with a gas burner and boiled for 2 hours while appropriately adding deionized water to keep the sulfuric acid concentration at 3%. After the treatment, the content is filtered using a constant-valued 1G4 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 is measured. I asked. The filtrate was measured for ultraviolet absorption at 205 nm by 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-soluble lignin and 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)
[0064]
FIG. 5 shows a graph of the lignin content in the primary lignophenol derivative-containing composition.
Immediately after the addition of the aqueous sulfuric acid solution, blackening was observed in all samples. In the sample using 60 wt% sulfuric acid, there was a sticky viscosity in the early stage of the reaction regardless of the presence or absence of ultrasonic irradiation, but in the case of the 65 wt% and 72 wt% sulfuric acid-treated samples, the viscosity no longer appeared when the acid was added. I was not able to admit. This is because the cell wall did not swell sufficiently at the time of treatment with 60 wt% sulfuric acid, so that the viscosity was generated only after the addition of 72 wt% sulfuric acid in the subsequent stage, and the cell wall had already swelled at the time of treatment with 65 wt% sulfuric acid and 72 wt% sulfuric acid. It is considered that the viscosity did not increase even if 72 wt% sulfuric acid was added in the latter stage.
[0065]
At the stage where the sulfuric acid concentration was diluted to 3 wt%, the ultrasonically treated sample turned blacker than the control sample, but turned red with boiling. This is considered to be because secondary denaturation was suppressed by the conversion of lignin.
As a whole, the longer the processing time in the introduction step, the higher the lignin content tended to be. This corresponds to the fact that the longer the reaction time, the more the carbohydrate is hydrolyzed and the lower molecular weight carbohydrate fraction flows out into the aqueous phase. The acid-soluble lignin showed a higher value than usual. This indicates that the phenol derivative was introduced into the lignin matrix at the C1 position, which is the active side chain, by sonication, and the low molecular weight fraction that could not be self-condensed due to suppression of secondary denaturation flowed out into the filtrate. It is thought to be caused by
[0066]
(Example 3)
Introduction of additional phenolic compound to primary lignophenol derivative (preparation of secondary phenol derivative)
In this embodiment, two kinds of phenol derivatives are introduced into the lignin matrix by a phase separation treatment using another phenol derivative different from the phenol derivative used in the primary treatment. Hereinafter, the frequency of introduction of the phenol derivative introduced into the lignin matrix by the primary conversion process and the secondary conversion process will be compared.
[0067]
A primary treatment composition was weighed in a 50 ml centrifuge tube in a 50 ml centrifuge tube with a prescribed amount (400 mg of a 72 wt% sulfuric acid treatment composition having a small total body weight, 600 mg of a sulfuric acid treatment sample of 65 wt% ultrasonic irradiation irradiation, and 700 mg of the other samples). A phenol compound (using p-ethylphenol as a phenol compound and using a mixed medium of p-ethylphenol: benzene = 7: 3) in a prescribed amount (4 ml of a 72 wt% sulfuric acid-treated composition having a small total body weight, ultrasonic wave) 6 ml of the irradiated 65 wt% sulfuric acid-treated composition and 7 ml of the others were added, and the mixture was stirred for about 10 minutes by hitting with a stirring blade. Thereafter, a prescribed amount of a 72 wt% sulfuric acid aqueous solution which had been previously heated to 30 ° C. was added (8 ml for a 72 wt% sulfuric acid-treated composition having a small total body weight, 12 ml for a 65 wt% sulfuric acid-treated composition with ultrasonic irradiation, and 14 ml for the other). After stirring for about 1 minute, the mixture was placed on a stirrer and stirred in a 30 ° C. water bath 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).
[0068]
150 ml of diethyl ether was added to a 200 ml Erlenmeyer flask, and the organic phase was added dropwise while cooling with water and stirring vigorously with a stirrer. Then, a few ml of a phenol derivative was added to the reaction vessel for washing the interface, and centrifugation [25 ° C., 3500 rpm (2200G) for 3 minutes], and the organic phase was added dropwise to ether. Washing was performed three times in total. Then, the mixture was stirred until the oily substance settled out and the supernatant liquid became clear. However, when the supernatant was not cleared even after stirring for 1 hour, insolubles were collected by centrifugation [5 ° C., 3500 rpm (2220 G), 10 minutes]. The supernatant was removed, and the precipitate and the vessel were further washed twice with about 15 ml of diethyl ether. Then, 40 to 60 ml of acetone was added to the precipitate, and the mixture was stirred until completely dissolved, and transferred to a centrifuge tube. And washed with acetone. The supernatant was transferred to a centrifuge tube, centrifuged (5 ° C., 3500 rpm (2220 G), 5 minutes), and then filtered using a glass fiber filter paper. Thereafter, the mixture is transferred to a 100 ml eggplant-shaped flask, concentrated to about 10 ml by an evaporator, dropped into diethyl ether, and the formed sediment is collected by centrifugation [5 ° C., 3500 rpm (2220 G), 5 minutes], and precipitated for washing. The product was added with diethyl ether and washed about three times.
The resulting precipitate was stored at room temperature in a dark place for 1 day to remove diethyl ether. Thereafter, the solution was dried under reduced pressure over nirin pentoxide in a centrifugal tube, the constant weight was measured, and the yield was determined. This was designated as a secondary lignophenol derivative.
[0069]
(Example 4)
Amount of first and second phenol derivatives introduced About 20 mg of various secondary lignophenol derivatives and about 3 mg of p-nitrobenzaldehyde (PNB) as an internal standard substance were placed in a screw vial with an lmI Teflon (registered trademark) liner. The mixture was precisely weighed, and 150 μl of deuterated pyridine was added thereto using a 1 ml volume pipette to dissolve completely. After dissolution, 450 μl of deuterated chloroform containing 0.03% of tetramethylsilane was added using a 1 ml volume pipette. After confirming complete dissolution, the sample solution was filtered with cotton, put into an NMR measurement tube (diameter 5 mm), and measured with an ALPHAFT NMR Spectrometer (manufactured by JEOL).
[0070]
In the obtained NMR chart, it was recognized that the proton signal of the methyl group of p-cresol introduced in the primary treatment and the proton signal of the ethylene group of the p-ethylphenol nucleus introduced in the secondary treatment overlapped. For this reason, the amount of p-cresol to be introduced is classified at the boundary (2.30 ppm) between the proton signal of the methyl group of p-cresol and the proton signal of the ethylene group of p-ethylphenol, and the integrated value of p-cresol is calculated. The proton signal amount of the methylene group of p-ethylphenol was calculated from the calculation formula (2) to be calculated and the integral value of the methyl proton signal of the ethyl group in p-ethylphenol (1.40 to 0.80 ppm). The introduced amount was determined from the formula (3) for correcting the introduced amount of the p-cresol nucleus, and the introduced phenol amount was determined from these formulas using the formula (4).
The amount of p-ethylphenol introduced was determined by the following equations (1) and (4).
[0071]
(Equation 1)

Formula (1)
(Equation 2)

Formula (2)
[Equation 3]

Formula (3)
(Equation 4)

Formula (4)
[0072]
IWt (%): Introduced phenol (Wt%)
Pwt: weight of PNB (mg)
Pm: molecular weight of PNB = 151
Pn: number of aromatic nuclei in PNB = 4
Pi: Integral value of a region showing an aromatic nucleus 4H signal in PNB (8.40 to 7.80 ppm) Ci: Integral value of a region showing a methyl 3H signal in p-cresol (2.30 to 1.80 ppm) Cn: Proton number of methyl group in p-cresol = 3
Cm: molecular weight of p-cresol = 108
Ei: integrated value of a region (1.40 to 0.80 ppm) of methyl 3H signal of ethyl group in p-ethylphenol En: number of methyl protons of ethyl group in p-ethylphenol = 3
Em: molecular weight of p-ethylphenol = 122
si: integrated value of a region (2.60 to 1.80 ppm) indicating a signal of a methyl proton signal of p-cresol and a signal of a methylene proton of an ethyl group in p-ethylphenol Lwt: weight of lignofer Imo1 / C ₉ : amount of introduced phenol Is (mo1 / C ₉ )
Lm: molecular weight of 1 unit of lignin = 2000 (conifer)
[0073]
6 and 7 show the amount of p-cresol introduced into the secondary lignophenol derivative, and FIG. 8 shows the amount of p-ethylphenol introduced. 9 and 10 show the amounts of p-cresol and p-ethylphenol introduced together. 6 and 7 are based on the amounts of p-cresol introduced, which were determined by the equations (2) and (3), respectively. Similarly, FIGS. 9 and 10 are based on the amounts of p-cresol introduced, which are obtained by the calculation formulas (2) and (3), respectively.
[0074]
As shown in FIGS. 6 to 10, the introduction of the second phenol compound, p-ethylphenol, was confirmed in all the secondary lignophenol derivatives. As shown in FIG. 8, the control sample showed a higher p-ethylphenol introduction amount at any acid concentration. This indicates that the introduction of p-cresol, which is the first phenol compound into lignin, was promoted by ultrasonic irradiation during the primary treatment, and the remaining active side chains in the primary lignophenol derivative were reduced. ing.
[0075]
Focusing on the amount of p-cresol introduced as the first phenol compound, no significant difference was observed between the 60% by weight sulfuric acid-treated samples. Also, in the case of the 65 wt% sulfuric acid-treated sample, the introduction amount was slightly larger in the ultrasonic treatment sample. On the other hand, in the case of the 72 wt% sulfuric acid-treated sample, the introduction amount was larger in the ultrasonic treatment sample, but in all cases, the increase in the introduction amount was stopped in about 10 minutes. This is because the 72 wt% sulfuric acid sufficiently swells the plant cell wall and promotes the decomposition of lignin, and the low molecular weight fraction in the secondary lignophenol derivative where the amount of the phenol compound introduced is high is the ether-soluble fraction. It seems that it was leaked in minutes. The introduction amount of the ultrasonically treated sample tended to decrease after 10 minutes, and the introduction amount of the control sample tended to increase after 10 minutes.
[0076]
As shown in FIGS. 9 and 10, the total amount of the introduced phenol compound was the highest in the 72 wt% sulfuric acid-treated sample. This is because the complex state of cellulose and lignin was sufficiently relaxed during the primary conversion, the accessibility of the phenol compound and acid to lignin was improved, and the phenol compound in the primary lignophenol derivative was highly introduced. It can be said that it is a result.
Further, as is clear from FIGS. 9 and 10, the higher the strength of the acid used in the primary treatment, the higher the introduction rate of the first phenol compound and the lower the introduction rate of the second phenol compound. The ratio of the first phenol compound to the second phenol compound changed significantly.
Furthermore, when the control sample and the sonicated sample that were not subjected to the sonication were compared, in the sonicated sample, the introduction amount of the first phenol compound was high as a whole, and the total amount of the introduction amount was also high. .
According to the above results, the amount of the phenol compound introduced in each step can be adjusted by changing the strength of the acid used, the presence or absence of ultrasonic treatment, and the like in the primary conversion step and the secondary conversion step. It was found that the introduction ratio of two or more phenol compounds could be controlled. In particular, it has been found that it is preferable to introduce a phenol compound which is desired to obtain a relatively large amount of introduction in the primary conversion step in which high intensity and ultrasonic irradiation are performed. Further, in order to approximate or highly control the introduction ratio of two or more phenolic compounds, in the first step or the preceding step, the ultrasonic treatment conditions or ultrasonic treatment are performed under moderate or weak acid strength. It was also found that it was possible by controlling the presence or absence of
[Brief description of the drawings]
FIG. 1 is a diagram showing various lignophenol derivatives obtained by introducing a phenol compound into lignin of a lignocellulosic material.
FIG. 2 is a conceptual diagram showing that various secondary lignophenol derivatives can be obtained by performing a primary conversion step (step (a)) and a secondary conversion step (step (b)).
FIG. 3 is a view showing a process flow of one method of the present invention for performing the step (a) and one step (b).
FIG. 4 is a graph showing the yield of a composition containing a lignophenol derivative per absolutely dry wood powder.
FIG. 5 is a graph showing a lignin content in a primary lignophenol derivative-containing composition.
FIG. 6 is a graph showing the amount of p-cresol introduced into a secondary lignophenol derivative obtained in an example (based on calculation by calculation formula (2)).
FIG. 7 is a diagram showing the amount of p-cresol introduced into the secondary lignophenol derivative obtained in the example (based on calculation by calculation formula (3)).
FIG. 8 is a graph showing the amount of p-ethylphenol introduced into a secondary lignophenol derivative obtained in an example.
FIG. 9 is a diagram showing the amounts of p-cresol and p-ethylphenol introduced into the secondary lignophenol derivative obtained in the example (based on calculation by calculation formula (2)).
FIG. 10 is a graph showing the amounts of p-cresol and p-ethylphenol introduced into the secondary lignophenol derivative obtained in the example (based on calculation by calculation formula (3)).

Claims (13)

A method for producing a phenol derivative of lignin,
The following steps:
(A) a step of adding an acid to a lignocellulosic material preliminarily affinityd with a first phenolic compound to obtain a primary lignin phenol derivative; Adding an acid to the lignin phenol derivative to obtain the (n + 1) th lignin phenol derivative;
The above (b) steps are sequentially performed a total of N times from 1 to N (N is an integer of 1 or more), and an (n + 1) -th lignin phenol derivative is obtained in each step (b). Method. The method according to claim 1, wherein in the step (b), N is an integer of 1 or more and 3 or less. The said n-th lignin phenol derivative used in the said (b) process is supplied as a composition containing at least one part of the carbohydrate derived from the lignocellulosic material produced simultaneously in the said (a) process. The method described in. The acid used in at least one step of the step (b) is a different kind of acid from the acid used in the step (a), or is used at a different strength from the acid used in the step (a). A method according to any one of claims 1 to 3. The method according to any one of claims 1 to 4, wherein the acid used in the step (a) is added with a strength capable of swelling the lignin-cellulose matrix. The method according to any one of claims 1 to 4, wherein the acid used in the step (a) is added with a strength that does not swell the lignin-cellulose matrix. The method according to any one of claims 1 to 6, wherein in any step of obtaining the lignin phenol derivative, a lignocellulose-based material or a mixed system containing a phenol derivative and a phenol compound is irradiated with ultrasonic waves. The method according to any one of claims 1 to 7, wherein in any step of obtaining the lignin phenol derivative, ultrasonic waves are applied to a lignocellulose-based material or a mixed system containing a lignophenol derivative, a phenol compound and an acid. The acid in the step (a) is added at least with a strength capable of swelling the lignin-cellulose matrix in the lignocellulosic material, and the mixture is mixed with the first phenol compound, the lignocellulose material and the acid. The method according to claim 1, wherein ultrasonic waves are applied. The acid in the step (a) is added at least so as not to swell the lignin-cellulose matrix in the lignocellulosic material, and is added to the mixed system containing the first phenol derivative, the lignocellulosic material and the acid. The method according to claim 1, wherein a sound wave is irradiated. The method according to any one of claims 1 to 10, wherein the first phenol compound and the second phenol compound include different types of phenol compounds. A composition obtained by the method according to any one of claims 1 to 11, comprising a phenol derivative of lignin into which two or more phenol compounds have been introduced. The composition according to claim 12, further comprising at least a part of a carbohydrate derived from the lignocellulosic material generated in the step (a).

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