JP5071772B2 - Method for producing lignophenol - Google Patents

Description

  The present invention relates to a method for producing lignophenol capable of controlling the molecular weight of a phenolic lignin polymer derived from a natural product (hereinafter referred to as lignophenol). More specifically, the present invention relates to a method for producing lignophenol, which can divide lignophenol as a raw material into molecular weights suitable for use.

  In recent years, research and development on effective utilization of lignophenol derived from lignin, which has been conventionally discarded, has been performed when using plants. Examples of plants include wood, grass, waste wood, and building waste. Patent Document 1 discloses a method of extracting lignophenol by phase-separating plant-derived lignocellulose. Lignophenol is dissolved in an organic solvent, applied to various materials, and then dried to form a molded body. When the molded body becomes unnecessary, it can be reused by dissolving it in an organic solvent and recovering it.

  In recent years, application studies on lignophenol have been conducted, and a wide range of uses for paints, electronic and electrical materials, medicines, and the like are expected as applications other than molded articles. Lignophenol is a polymer having a range of 300 to 100,000 and generally has a broad molecular weight distribution. For applications where a state having a broad molecular weight distribution is desirable, it can be used as it is, but there are applications where a narrow molecular weight distribution, a higher molecular weight, or a lower molecular weight lignophenol is desirable.

  Laboratory methods for obtaining, ie, fractionating, lignophenols having different molecular weights include gel permeation chromatography (GPC), size exclusion chromatography (SEC), and a method using a column packed with an adsorbent.

Japanese Patent Laid-Open No. 02-233701

  However, the conventional laboratory method for lignophenol fractionation has a very small throughput and takes a long time to divide the molecular weight. As a result, it is not a method suitable for economical and industrial mass production. For this reason, there has been no efficient method for controlling the molecular weight division and distribution of lignophenol so far, and natural product-derived lignophenol had to be used with a wide molecular weight distribution.

  In view of the above problems, an object of the present invention is to provide a method for producing lignophenol, which can fractionate lignophenol and derivatives thereof into molecular weights according to their uses.

  As a result of extensive research, the present inventors investigated the solubility and affinity of lignophenol in a solvent and selected the type of poor solvent, that is, by appropriately selecting the poor solvent, the molecular weight and molecular weight of lignophenol. The distribution can be controlled, and further, after recovering lignophenol from the poor solvent, a complex-like complex of lignophenol and metal compound is introduced into the poor solvent, and the lower molecular weight lignophenol remaining in the poor solvent is introduced. The inventors have found that it can be recovered and have reached the present invention.

In order to achieve the above object, the method for producing lignophenol of the present invention comprises a step of dissolving lignophenol as a starting material in a parent solvent to form a parent solvent solution of lignophenol, and the parent solvent solution is R ₁ -O. -R ₂ type asymmetric ethers (wherein R ₁ and R ₂ are any group of alkyl, isoalkyl, tert-alkyl, phenyl and allyl, which are different from each other, and R ₁ and the total number of carbon atoms of the substituents represented by R ₂ is 4 or more. and a recovering added resulting precipitate in a poor solvent represented by), characterized in Rukoto.
As a poor solvent by selecting R ₁ -O-R ₂ type asymmetrical ethers by mixing parent solvent solution of the lignophenol, it is possible to produce a lignophenol molecular weight is controlled.

Another method for producing lignophenol according to the present invention is a step of dissolving lignophenol as a starting material in a parent solvent to obtain a lignophenol parent solvent solution, and adding titanium oxide nanoparticles to the lignophenol parent solvent solution. , Forming a complex-like complex composed of lignophenol and titanium oxide nanoparticles, and converting the complex-like complex into R ₁ —O—R ₂ type asymmetric ethers (where R ₁ and R ₂ are alkyl, Any one of isoalkyl, tert-alkyl, phenyl and allyl, which are different from each other, and the total number of carbon atoms of the substituents represented by R ₁ and R ₂ is 4 or more). And a step of recovering the resulting precipitate in addition to the poor solvent to be produced .
According to the said structure, the complex-like complex which consists of lignophenol and a metal compound can be added in a poor solvent, and the remaining lignophenol can be collect | recovered.

In the above structure, the poor solvent is preferably an R ₁ —O—R ₂ type ether (wherein R ₁ and R ₂ are any group of alkyl, isoalkyl, tert-alkyl, phenyl, and allyl). And the total number of carbon atoms of the substituents represented by R ₁ and R ₂ is 4 or more. The ethers are preferably tert-butyl methyl ether or cyclopentyl methyl ether. The poor solvent is selected from at least two of asymmetric ethers, symmetric alkyl ethers, and cyclic hydrocarbons, and may be a mixture of the selected poor solvent in an arbitrary ratio.
Preferably, the asymmetric ether is tert-butyl methyl ether or cyclopentyl methyl ether, the symmetric alkyl ether is dipropyl ether or diethyl ether, and the cyclic hydrocarbon is toluene, xylene, or hexane. .
According to the said structure, the molecular weight of lignophenol can be controlled with the solvent which mixed the kind of poor solvent, and a different poor solvent.

  According to the method for producing lignophenol of the present invention, lignophenol having a desired molecular weight can be efficiently produced by selecting a poor solvent according to the molecular weight of the target lignophenol.

The best mode for carrying out the present invention will be described below with reference to the drawings.
FIG. 1 is a process diagram showing a method for producing lignophenol of the present invention. In the figure, starting material 1 is lignophenol derived from lignocellulose. As shown in the figure, the first step is a step of dissolving lignophenol as a starting material 1 in a parent solvent, and is used as a lignophenol parent solvent solution. The second step is a step of mixing the lignophenol parent solvent solution obtained in the first step into the lignophenol poor solvent, and a lignophenol precipitate is produced in the poor solvent. This precipitate is lignophenol in which the molecular weight of lignophenol used as the starting material 1 is changed. The molecular weight of the lignophenol precipitate can be controlled by changing the solubility of the poor solvent in the lignophenol parent solvent solution.

The lignocellulose used as the raw material for lignophenol will be described.
Lignocellulose itself is the main component of the plant, and any of woody plants and herbs such as conifers and hardwoods can be used. For woody materials, wastes, thinned wood, wood flour, etc., and herbaceous agricultural waste such as kenaf, bagasse, oil palm empty bunch, and industrial waste such as herbaceous plants, newspapers, and coffee galley can also be used. Lignocellulose consists of about 70% sugar and about 30% lignin, which is a hard part. Conventionally, only useful carbohydrates have been extracted, and lignin that is difficult to extract due to high reactivity has been discarded. The characteristics when using wood, which is one of these raw materials, are shown below.
The conifers are all guaiacyl type having an arylmethyl ether (methoxyl group) at the 2-position of the phenyl moiety of the phenylpropane structure. Hardwood has a syringyl type with a methoxyl group at 50:50 at the 2-position and 5-position of the phenyl portion at the same time as the guaiacyl type. Furthermore, herbaceous plants have a phenylpropane skeleton without a methoxyl group in addition to a hardwood-type basic skeleton. Except for such basic skeleton, the structure of the obtained lignophenol is almost the same regardless of which tree species is used. In conifer lignophenol, the intermolecular bond is formed from the 5-position of the phenyl portion of the guaiacyl group, so that the molecular weight is relatively high. For conifers, the weight average molecular weight Mw is about 10,000 to 20,000, and for hardwoods and herbs, Mw is about 6000 to 8,000.

  The difference in molecular weight and the difference in structure are reflected in the thermal pour point measured by, for example, thermomechanical analysis (TMA), and the flow begins at about 170 ° C. for conifers, whereas it is about 140 ° C. for hardwoods. Structural analysis by NMR or FT-IR shows almost the same numerical value. Furthermore, when the molecular switch is operated under an alkali, the molecular weight is reduced regardless of the tree species, so it can be considered that the C2-O-aryl structure, which is the basic skeleton of the polymer, also exists. Thus, the molecular structure and molecular weight distribution can be designed freely according to the application.

In the production method of the present invention, the lignophenol used as the starting material 1 is a phase-separated system conversion in which the lignocellulose used as a raw material is converted into a phenol-substituted product using phenols, and the phenol-substituted product is phenolized by an interfacial reaction with concentrated acid. It can be extracted by the system (see Patent Document 1).
FIG. 2 is a diagram showing a chemical reaction formula for converting lignin to p-cresol-type lignophenol. In the reaction shown in FIG. 2, lignin 10 is converted to a phenol-substituted product using p (para) -cresol and reacted with sulfuric acid (H ₂ SO ₄ ) to form p-cresol-type lignophenol 1 as a starting material and water-soluble. Separated into carbohydrates (sugars).

  Examples of phenols other than p-cresol include phenol, m (meth) -cresol, o (ortho) -cresol, anisole, 2,4-dimethoxyphenol, 2,6-dimethoxyphenol, 2,4-dimethylphenol, 2,6-dimethylphenol, propylphenol, i-propylphenol, tert-butylphenol, catechol, resorcinol, pyrogallol, phloroglucinol, bisphenol, vanillin, syringol, guaiagol, ferulic acid, coumaric acid, or these A combination of can be used.

The structural characteristic of the lignophenol used as the starting material which concerns on this invention is shown.
Lignophenol is an amorphous polymer having the following structural characteristics. When a phenolic substance contained in a plant at 20 to 30% and having a phenylpropane skeleton (C6C3) is subjected to a phenolization treatment by an interfacial reaction with an excess of phenols (for example, p-cresol) under an acid catalyst, Phenol is introduced mainly at the C1 position of the phenylpropane skeleton and nucleophilically introduced so that the hydroxyl group is ortho to the C1, and a phenolic lignin structure variable polymer (lignophenol) is obtained almost quantitatively (Fig. 2 1-1, bis (aryl) propane-2-O-aryl ether type structure).

  The phenolic nature of the obtained lignophenol depends mainly on the type of phenol introduced. At the same time, the inter-unit bond forming the three-dimensional structure of lignin present at the C1 position is cleaved, leading to a polymer compound having a relatively linear structure. The linear structure has a C2-O-aryl ether skeleton, which is the basic skeleton of natural lignin. This aryl ether is bonded to the phenyl part and the 4-position of the phenylpropane chain. An aliphatic hydroxyl group exists at the terminal C3 position of the propane chain and forms abundant hydrogen bonds with the phenolic hydroxyl group.

  Lignophenol itself can be hydrophobized by selecting phenols such as p-cresol, m-cresol, o-cresol, 2,4-dimethylphenol, 2,6-dimethylphenol, propylphenol among the above phenols. .

  On the other hand, lignophenol obtained from catechol, resorcinol, pyrogallol, phloroglucinol, hydroquinone, etc. has high hydrophilicity. Derivatives such as hydroxymethylated lignophenol are also hydrophilic because they are rich in hydrogen bonds.

  The lignophenol thus obtained is a polymer having a wide molecular weight distribution, and it is desirable to divide and provide lignophenol having a high or low molecular weight depending on the application. Attempts were made to control the size and distribution of molecular weight to some extent by changing the ratio of a parent solvent such as acetone and a poor solvent such as diethyl ether during precipitation.

  Here, the lignophenol used as the starting material 1 is not only lignophenol obtained by the reaction described in FIG. 2, but lignophenol obtained by physical treatment such as heat, lignophenol, and simple lignophenol and cellulose. A complex of a simple lignophenol and a synthetic polymer, a secondary derivative of a simple lignophenol, a higher-order phenol introduction of a simple lignophenol, and a stable complex-like complex of simple lignophenol and a metal compound. be able to. The above lignophenol other than lignophenol alone will be referred to as a lignophenol derivative. The lignophenol used as the starting material 1 of the present invention contains simple lignophenol and lignophenol derivatives.

The feature of the present invention is that the lignophenol used as the starting material 1 is dissolved in a parent solvent, and the lignophenol parent solvent solution is mixed in the lignophenol poor solvent, so that lignophenol precipitates having different molecular weights are mixed. There is to get.
As a result of examining the solubility of lignophenol used as the starting material 1 in various solvents, it was found that the solubility was as follows.
Strong alkaline solution> Alkyl ketones such as acetone and methyl ethyl ketone> Aprotic polar solvents such as dimethylformamide (DMF) and N-methylpyrrolidone (NMP)> Cyclic ethers such as tetrahydrofuran (THF) and dioxane> Pyridine Heterocyclic compounds> alcohols such as ethanol and cellosolve> asymmetric ethers such as tert-butyl methyl ether (TBME) and cyclopentyl methyl ether (CPME)> symmetric alkyl ethers such as diethyl ether, dipropyl ether and diisopropyl ether > Toluene or a mixed solvent of xylene and hexane> Cyclic hydrocarbons such as benzene, toluene, hexane> Water

  Among the above solvents, alkyl ketones such as acetone and alcohols such as ethanol and cellosolve can be used as a parent solvent because lignophenol has high solubility. For lignophenol of the type into which hydrophilic phenol such as catechol or pyrogallol having high water solubility is introduced, water can also be used as a parent solvent.

  In the process of producing lignophenol as the starting material 1, it is necessary to dissolve unreacted phenolic compounds such as p-cresol and low molecular weight lignin at the same time, so it is difficult to use benzene, hexane and toluene alone. Commonly used as a mixed solvent.

Therefore, as the poor solvent, considering the process of use and recovery, the affinity for lignophenol is also considered, and R ₁ —O—R ₂ type ethers (where R ₁ and R ₂ are alkyl, isoalkyl , Tert-alkyl, phenyl, allyl, and the total number of carbon atoms of the substituents represented by R ₁ and R ₂ is 4 or more. Such ethers are preferably asymmetric ethers, such as tert-butyl methyl ether or cyclopentyl methyl ether. Cyclopentyl methyl ether (CPME) has the advantage that the generation of peroxide is suppressed to a very small level even when handled in air, and it can be handled industrially safely even when heated and concentrated during solvent recovery.

Another poor solvent may be selected from at least two of asymmetric ethers, symmetric alkyl ethers, and cyclic hydrocarbons, and a mixture of two selected poor solvents in an arbitrary ratio. Asymmetric ethers include tert-butyl methyl ether or cyclopentyl methyl ether. Symmetric alkyl ethers include dipropyl ether or diethyl ether. As the cyclic hydrocarbon, any of toluene, xylene, and hexane can be used.
According to the poor solvent, not only the molecular weight of precipitated lignophenol but also the distribution can be controlled.

  The amount of the lignophenol parent solvent solution introduced into the poor solvent may be about 3 to 50% by weight. If it is outside this range, the solubility of lignophenol is increased by the influence of the parent solvent, and the lignophenol dissolved in the parent solvent is not sufficiently aggregated, so that the precipitation thereof is not preferable.

By the above method, lignophenol remains also in the poor solvent after lignophenol is precipitated from the poor solvent. A method for producing lignophenol capable of recovering this lignophenol will be described.
FIG. 3 is a process diagram showing another method for producing lignophenol of the present invention.
As shown in FIG. 3, the first step and the second step are the same as the method of fractionating lignophenol shown in FIG. 1, and as the third step, the poor solvent after recovering the lignophenol precipitate and A step of adding a complex-like complex of lignophenol and a metal compound to a parent solvent and recovering the remaining lignophenol as a precipitate is added. The complex-like complex of lignophenol and metal compound acts as an adsorbent for lignophenol, and adsorbs the lignophenol remaining in the poor solvent and the parent solvent in the second step and can be recovered as a precipitate. .

  Lignophenol and its derivatives form a stable complex-like complex with the metal compound, and thus form a strong complex with the metal compound. Examples of the metal compound include metal oxides and metal sulfides. A transition metal can be used as the metal. Of these, titanium oxide and magnetite are particularly useful. Titanium oxide can be used as a simple substance, and further, a titanium oxide nanoporous film-like substance described later can be used.

  In particular, the anatase-type titanium oxide crystal can not only improve the strength of the lignophenol-based adsorption medium but also improve the adsorption characteristics. From the viewpoint of the strength of the complex-like composite compound to be produced, it is preferable that the primary particle size of the metal compound to be used is small, but it is extremely difficult to adjust nanoparticles smaller than the nm order. In the case of using titanium oxide or a titanium oxide nanoporous film-like substance described later, it is desirable that the primary particles have a particle size in the range of 1 nm to 10 μm. If the particle size of the primary particles is smaller than 1 nm, it is difficult to adjust the nanoparticles themselves, which is not preferable. Conversely, if the primary particle size exceeds 10 μm, the strength of the complex-like composite compound tends to decrease, which is not preferable. Here, the primary particle means the smallest continuum unit having a crystalline state. This titanium oxide nanoporous film also forms a complex-like complex with lignophenol as in the case of titanium oxide alone.

  According to the said manufacturing method, the lignophenol which the solvent remains after collect | recovering lignophenol at a 2nd process can be collect | recovered. For example, lignophenol having a large molecular weight can be recovered in the second step, and lignophenol having a different molecular weight that cannot be recovered in the second step can be recovered in the third step. That is, lignophenols having different molecular weights can be separated and recovered in a series of steps.

The titanium oxide film described above can be prepared, for example, as follows.
10 parts by weight of titanium oxide nanoparticle paste (catalyst conversion, PASOL-HPA-15R), 1 part by weight of titanium oxide (manufactured by Nippon Aerosil Co., Ltd., P25), polyethylene glycol (manufactured by Wako Pure Chemical Industries, Ltd., special grade) , Molecular weight 20000) and 4 parts by weight were thoroughly stirred in an agate mortar. The thickness of this paste was adjusted with a 63 μm thick mending tape (manufactured by 3M Co.) on conductive glass (FTO) coated with fluorine-doped tin oxide, and the paste was applied by a bar coating method. After drying, it was sintered in a muffle furnace at 450 ° C. for 60 minutes. The thickness of the obtained titanium oxide film was 10 μm to 45 μm. As a result of observation with a scanning electron microscope (SEM), particles of 1 μm or less were confirmed.

  According to the production method shown in FIG. 1 and FIG. 3, lignophenol having a different molecular weight can be efficiently recovered from the lignophenol obtained as the starting material 1. Further, as the lignophenol of the starting material 1, a complicated composition including a narrow material can be used. For example, the lignophenol used as the starting material 1 is a low-molecular phenolic component derived from unreacted phenols and lignin during the lignophenol production process, an aliphatic component derived from lignin, and a cellulose degradation product derived from plant raw materials. It is also effective for separating and recovering lignophenol from a composition containing impurities such as saccharides and controlling the molecular weight.

  The precipitate made of lignophenol recovered in the second step and the third step is washed and dried, and the lignophenol in the dried precipitate is immersed in an organic solvent or an alkaline solution in which lignophenol is well dissolved. Can be separated and recovered. The complex-like complex of lignophenol and metal compound used in the third step is modified as a complex-like complex of lignophenol and metal compound such as titanium oxide by acidification after dissolving in an alkaline solution. It is possible to recover to the original state without doing so.

  The use of lignophenol having a high molecular weight produced according to the present invention, that is, high-molecular-weight lignophenol, is enhanced by direct use as a polymer of lignophenol for moldings or by hydroxymethylation for the purpose of making a resol type phenol resin. Examples include prepolymer applications for inducing molecular weight, and polymer usable prepolymer applications such as urethanization and epoxidation for the purpose of plasticization. Low molecular weight lignophenol can be used as a material for pharmaceutical applications such as virus inhibitors and antiallergens, UV absorbers for plastics, additives such as plasticizers, and electronics applications such as photosensitizers for photochemical batteries. it can.

Hereinafter, the embodiments of the present invention will be described in more detail by way of examples. However, the present invention is not limited to these examples.
First, lignophenol as a starting material 1 was produced by the following method.
500 g of p-cresol was dissolved in 17 liters of acetone, and then added to 1000 g of air-dried cypress (Chamaecyparis obtusa) wood powder from which the extract was removed, and left for several hours. Acetone was removed, and 1 unit of lignin of p-cresol remaining in the wood flour (phenylpropane structure C6C3) was 3 mol times per mol. 5 liters of sulfuric acid (72%) was added to the wood flour to which p-cresol was adhered, and the mixture was vigorously stirred at room temperature for 1 hour. After removing the acid by washing with water and drying, the mixture was extracted by adding 7 liters of acetone, and the extract was concentrated to about 3 liters to obtain a lignophenol parent solvent solution.
When 3 liters of the concentrated acetone extract (54.2 mg / cm ³ ) was dropped into 20 liters of diethyl ether with magnetic stirring, and the physical properties of 140 g of lignophenol obtained as a precipitate were evaluated by GPC analysis, The average molecular weight (Mw) was 13436. In the measurement by thermomechanical analysis (TMA), the heat flow starting point temperature was 165.8 ° C. and the end point temperature was 181.1 ° C.

As a second step shown in FIG. 1, the parent solvent solution (acetone extract, 54.2 mg / cm ³⁾ of the lignophenol a 20 cm ^3, cyclopentylmethyl ether (CPME) 200 cm ³ is used as the poor solvent, the lignophenol Lignophenol of Example 1 was obtained by dripping and mixing the parent solvent solution under magnetic stirring of a poor solvent. The solvent of the precipitate was collected as a result of concentrated by evaporation to a 175cm ³ of cyclopentyl methyl ether 200 cm ³ using recovered.

(Comparative Example 1)
As Comparative Example 1 with respect to Example 1, lignophenol of Comparative Example 1 was obtained in the same manner as in Example 1 except that the poor solvent in the second step was changed to 200 cm ³ of diethyl ether (DEE).

The physical properties of 0.6 g of lignophenol of Example 1 and 0.55 g of lignophenol of Comparative Example 1 were examined by gel permeation chromatography (GPC), thermomechanical analysis, and FT-IR spectroscopy.
4 is a graph showing the results of gel permeation chromatography of lignophenol obtained in Example 1 and Comparative Example 1. FIG. In FIG. 4, the horizontal axis represents elution time (minutes), and the vertical axis represents signal intensity (arbitrary scale). As is clear from FIG. 4, the number average molecular weight of lignophenol of Example 1 obtained using cyclopentyl methyl ether as a poor solvent is 7210, and lignophenol of Example 2 obtained using diethyl ether as a poor solvent. The number average molecular weight of was found to be 5325.

  FIG. 5 is a diagram showing the measurement results of a thermomechanical analysis method for lignophenol, in which (A) shows Example 1 and (B) shows Comparative Example 1. FIG. In FIG. 5, the horizontal axis represents temperature (° C.), and the vertical axis represents displacement (%) by TMA (thermomechanical analysis). As is clear from FIG. 5, the thermal fluid starting point temperature of lignophenol of Example 1 obtained using cyclopentyl methyl ether as a poor solvent was 167.5 ° C., and the end point temperature was 182 ° C. The lignophenol of Comparative Example 1 obtained using diethyl ether as a poor solvent had a heat flow starting point temperature of 162.7 ° C and an end point temperature of 179.1 ° C.

FIG. 6 is a diagram showing the measurement results of light transmittance of lignophenol obtained in Example 1 and Comparative Example 1 by FT-IR spectroscopy, where (A) shows Comparative Example 1 and (B) shows Example. 1 is shown. In FIG. 6, the horizontal axis is the wave number (cm ⁻¹ ), and the vertical axis is the light transmittance (arbitrary scale). As can be seen from FIG. 6, the light transmittance in the infrared region of Example 1 and Comparative Example 1 is almost the same, and thus the structural composition of Example 1 and Comparative Example 1 is almost the same. .

  From the above measurement results, comparing Example 1 using cyclopentyl methyl ether as a poor solvent and Comparative Example 1 using diethyl ether as a poor solvent, a higher molecular weight lignophenol was obtained in Example 1, It was found that the heat flow starting point temperature was also high, and it was found from the measurement results of FT-IR spectroscopy that the structural composition was almost the same as in Comparative Example 1.

  Lignophenol used as the starting material 1 was produced in the same manner as in Example 1 using air-dried cypress having the same tree species as in Example 1 but having a different origin. Lignophenol of Example 2 was obtained in the same manner as in Example 1 except that the poor solvent in the second step was changed to 200 g of tert-butyl methyl ether (TBME).

The poor solvent of the second step, and cyclopentyl methyl ether 100 cm ³ of unsymmetrical ethers, 1 diethyl ether 100 cm ³ of symmetrical alkyl ethers: 1 except that the (volume ratio) mixed poor solvent, as described in Example 2 Thus, lignophenol of Example 3 was obtained.

Lignophenol of Example 4 was obtained in the same manner as Example 2 except that the poor solvent in the second step was changed to 200 cm ^{3 of} cyclopentyl methyl ether.

(Comparative Example 2)
As Comparative Example 2 for Examples 2 to 4, lignophenol of Comparative Example 2 was obtained in the same manner as in Example 2 except that the poor solvent in the second step was changed to 200 cm ^{3 of} diethyl ether.

7 is a graph showing the results of gel permeation chromatography measurement of lignophenol obtained in Examples 2 and 3 and Comparative Example 2. FIG. In FIG. 7, the horizontal axis represents elution time (minutes), and the vertical axis represents signal intensity (arbitrary scale). As is clear from FIG. 7, the number average molecular weight of the lignophenol of Example 2 obtained using tert-butyl methyl ether as the poor solvent was 11854. The number average molecular weight of the lignophenol of Example 3 obtained using a mixed poor solvent of cyclopentyl methyl ether and diethyl ether as the poor solvent was 8918.
On the other hand, the number average molecular weight of the lignophenol of Comparative Example 2 obtained using diethyl ether as a poor solvent was 7871, which was found to be smaller than the number average molecular weight of the lignophenols of Examples 2 and 3.

  FIG. 8 is a graph showing the measurement results of gel permeation chromatography of lignophenol obtained in Example 4 and Comparative Example 2. In FIG. 8, the horizontal axis represents elution time (minutes), and the vertical axis represents signal intensity (arbitrary scale). As is clear from FIG. 8, the number average molecular weight of the lignophenol of Example 4 obtained using cyclopentyl methyl ether as a poor solvent was 9959.

  From the measurement result of the gel permeation chromatography, the number average molecular weight (Mn = 8918) of the lignophenol of Example 3 using a mixed poor solvent of cyclopentyl methyl ether and diethyl ether as the poor solvent was found to be the poor solvent of Example 4. The number average molecular weight (Mn = 9959) of lignophenol obtained using cyclopentyl methyl ether as the intermediate value and the number average molecular weight (Mn = 7871) of lignophenol obtained using diethyl ether as the poor solvent of Comparative Example 2 I found out that

FIG. 9 is a diagram showing the measurement results of the thermomechanical analysis of lignophenol obtained in Examples 2 to 4 and Comparative Example 2. In FIG. 9, the horizontal axis represents temperature (° C.), and the vertical axis represents displacement (%) by TMA (thermomechanical analysis).
As is clear from FIG. 9, the thermal fluid starting point temperature of lignophenol obtained using tert-butyl methyl ether as the poor solvent in Example 2 was 179.2 ° C., and the end point temperature was 203 ° C. . Lignophenol obtained using a mixed solvent of cyclopentyl methyl ether and diethyl ether as a poor solvent in Example 3 had a thermal flow starting point temperature of 177.0 ° C. and an end point temperature of 213.2 ° C. The thermal fluid starting point temperature of lignophenol obtained using cyclopentyl methyl ether as a poor solvent in Example 4 was 178.20 ° C., and the end point temperature was 202.2 ° C.
On the other hand, the thermal fluid starting point temperature of lignophenol obtained using diethyl ether as a poor solvent in Comparative Example 2 was 174.2 ° C., and the end point temperature was 199.3 ° C.
The number average molecular weight and flow start point temperature values of Example 1 and Comparative Example 1 are different from the measurement results of Example 4 and Comparative Example 2 using the same poor solvent. This is due to the use of cypress. Compared with the case where the poor solvent of Comparative Example 2 was diethyl ether, it was found that the molecular weight and distribution of Lignophenol of Example 2 and the order and tendency of thermal characteristics were the same.

FIG. 10 is a diagram showing the measurement results of light transmittance of lignophenol obtained in Examples 2 to 4 and Comparative Example 2 by FT-IR spectroscopy. In FIG. 10, the horizontal axis represents the wave number (cm ⁻¹ ), and the vertical axis represents the light transmittance (arbitrary scale). As is clear from FIG. 10, the light transmittance in the infrared region of lignophenol obtained in Examples 2 to 4 and Comparative Example 2 is almost the same, and the structures of lignophenol in Examples 2 to 4 and Comparative Example 2 are the same. The composition was found to be the same. In addition, although the lignophenol of Examples 2-4 and Comparative Example 2 was also measured by nuclear magnetic resonance (NMR), it turned out that all have the same structural composition.

The lignophenols of Examples 2 to 4 and Comparative Example 2 obtained as precipitates were measured by size exclusion chromatography (SEC), their properties were measured, and the weight average molecular weight (Mw) indicating the degree of sharpness of the distribution ) And the number average molecular weight (Mn) (Mw / Mn). The smaller the value of Mw / Mn, the steeper the molecular weight distribution. Table 1 is a table showing number average molecular weight (Mn), weight average molecular weight (Mw), Mw / Mn, and heat flow starting point temperature.

  As is apparent from Table 1, the weight average molecular weights (Mw) of the lignophenols of Examples 2, 3, 4 and Comparative Example 2 were 24774, 20366, 22512, 17962, respectively. The Mn / Mw of the lignophenols of Examples 2, 3, 4 and Comparative Example 2 were 2.09, 2.28, 2.26, 2.28, respectively. As for Mn / Mw obtained in Examples 2 to 4, Mn / Mw of lignophenol obtained with an equivalent mixed solvent of benzene and hexane is widened to about 3 to 4, whereas the value is small and a narrow distribution is obtained. Turned out to be.

  In the solvent in which lignophenol was precipitated in Example 1, a complex-like complex consisting of the following lignophenol and metal compound was used as the third step to recover the remaining lignophenol, and the lignophenol of Example 5 was recovered. Got.

  The complex-like complex of lignophenol and a metal compound was prepared by dissolving 10 g of lignophenol as starting material 1 obtained in Example 1 in 1 liter of acetone, and dissolving titanium oxide nanoparticles (Ishihara Sangyo Co., Ltd. 50 g of ST01) was mixed and acetone was distilled off to prepare a complex-like complex composed of lignophenol and titanium oxide nanoparticles.

60 g of this complex-like complex was put into 500 cm ³ of a 1 mol aqueous solution of sodium hydroxide and stirred in the dark for 24 hours, and 1 mol of hydrochloric acid (HCl) was added to the resulting alkaline solution in which lignophenol was dissolved. The pH was 2. The pH-adjusted lignophenol acidic solution 900 cm ³ was added to the poor solvent in the second step, and the resulting precipitate was recovered as the lignophenol of Example 5. As a result of measuring the molecular weight of the precipitated lignophenol by gel permeation chromatography, it was found that the number average molecular weight of lignophenol was 1500. Separately, the complex-like complex composed of the recovered titanium oxide nanoparticles could be repeatedly used by dissolving in an alkaline solution and then acidifying.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the invention described in the claims, and these are also included in the scope of the present invention. For example, it goes without saying that the extraction method of lignophenol used as the starting material 1 and the type of poor solvent used can be designed as appropriate.

  Until now, a production method of lignophenol capable of controlling the size and distribution of molecular weight has not been established. However, the present invention can industrially provide an optimal lignophenol material according to a wide range of applications, and to an application field. The ripple effect is very large.

It is process drawing which shows the manufacturing method of the lignophenol of this invention. It is a figure which shows the chemical reaction formula which converts lignin into p-cresol type lignophenol. It is process drawing which shows the other manufacturing method of the lignophenol of this invention. It is a figure which shows the measurement result of the gel permeation chromatography of the lignophenol obtained in Example 1 and Comparative Example 1. It is a figure which shows the measurement result of the thermomechanical analysis method of lignophenol, (A) shows Example 1, (B) has shown the comparative example 1. FIG. It is a figure which shows the measurement result of the light transmittance by FT-IR spectroscopy of the lignophenol obtained in Example 1 and Comparative Example 1, (A) shows Comparative Example 1, and (B) shows Example 1. Yes. It is a figure which shows the measurement result of the gel permeation chromatography of the lignophenol obtained in Example 2, 3 and the comparative example 2. It is a figure which shows the measurement result of the gel permeation chromatography of the lignophenol obtained in Example 4 and Comparative Example 2. It is a figure which shows the measurement result of the thermomechanical analysis method of lignophenol obtained in Examples 2-4 and Comparative Example 2. It is a figure which shows the measurement result of the light transmittance by FT-IR spectroscopy of the lignophenol obtained in Examples 2-4 and Comparative Example 2.

Explanation of symbols

1: Starting material (lignophenol)
2: Lignophenol (precipitate)
3: Lignophenol recovered from poor solvent 10: Lignin

Claims (6)

Dissolving lignophenol in a parent solvent to form a lignophenol parent solvent solution;
The lyosolvent solution is a R ₁ —O—R ₂ type asymmetric ether (wherein R ₁ and R ₂ are any group of alkyl, isoalkyl, tert-alkyl, phenyl and allyl, And the total number of carbon atoms of the substituents represented by R ₁ and R ₂ is 4 or more). And a method for producing lignophenol. The method for producing lignophenol according to claim 1, wherein the poor solvent is a solvent selected from tert-butyl methyl ether or cyclopentyl methyl ether. The method for producing lignophenol according to claim 1, wherein the poor solvent is a mixed solvent containing a solvent selected from tert-butyl methyl ether or cyclopentyl methyl ether. Dissolving lignophenol in a parent solvent to form a lignophenol parent solvent solution;
Adding a titanium oxide nanoparticle to a lignophenol parent solvent solution to form a complex-like complex composed of lignophenol and titanium oxide nanoparticles;
R ₁ —O—R ₂ type asymmetric ethers (wherein R ₁ and R ₂ are any group of alkyl, isoalkyl, tert-alkyl, phenyl, allyl, And the total number of carbon atoms of the substituents represented by R ₁ and R ₂ is 4 or more.), And a step of recovering the resulting precipitate. A process for producing lignophenol, characterized in that The method for producing lignophenol according to claim 4, wherein the poor solvent is a solvent selected from tert-butyl methyl ether or cyclopentyl methyl ether. The method for producing lignophenol according to claim 4, wherein the poor solvent is a mixed solvent containing a solvent selected from tert-butyl methyl ether or cyclopentyl methyl ether.