JP5146799B2 - Method for producing lignophenol - Google Patents

Description

The present invention relates to a method for producing lignophenol, which can efficiently produce lignophenol from lignocellulose.

  In recent years, oil prices have continued to rise due to an increase in demand for oil in China, India, etc., and investment targets by hedge funds. In addition, it is necessary to further promote the formation of a recycling-oriented society that suppresses the increase of greenhouse gases and the utilization of biomass resources in order to achieve the carbon dioxide reduction target set in the Kyoto Protocol for the prevention of global warming. Has been.

  Unlike renewable petroleum and coal, renewable biomass resources use carbon dioxide in the atmosphere as a carbon source, and even if they are burned and discarded, the use of biomass resources is desired because the increase in the concentration of atmospheric dioxide can be prevented. Among them, plant-derived lignocellulose resources have attracted attention as renewable materials, and much research has been conducted on their use as energy, such as thermochemical conversion such as biomass power generation and gasification, and ethanol production by fermentation. However, lignocellulosic resources, when used only as energy, exceed the regenerative capacity of plant resources, leading to the possibility of depletion of plant resources.

  In order to effectively use plant resources as alternative industrial raw materials for petroleum, it is important to derive raw materials for products necessary for daily life from plant resources as well as various organic chemical products derived from petroleum. In order to make full use of plant resources as molecular materials, it is important to efficiently separate each component of the plant complexed at the molecular level in a state where each function is utilized.

  The present inventors have developed a phase separation system conversion system for plant resources using phenols and concentrated acids, and the cellulose and hemicellulose carbohydrates and lignin, which are the main components of plants, are rapidly and quantitatively It succeeded in separating and converting easily (see Patent Document 1 and Non-Patent Documents 1 to 3). In the phase separation system conversion system, the phenols function as a protective medium from the lignin phenolization reagent, solvent, and concentrated acid, and the concentrated acid functions as a carbohydrate hydrolysis reagent, solvent, and lignin phenolization catalyst. Lignophenol derived by this technique has thermoplastic properties and high protein adsorption properties not found in lignin samples such as conventional industrial lignin (see Non-Patent Document 2).

  Examples of plants used in the phase separation system conversion system include wood, grass, waste wood, and building waste. Lignin derived by the above method (hereinafter referred to as 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 may be used as it is, but there are applications where a narrow molecular weight distribution, higher molecular weight, and lower molecular weight lignophenol are desirable.

The purification of lignophenol contained in the phenol phase requires the following two-stage purification.
(Primary purification)
Dropped in diethyl ether, diisopropyl ether or n-hexane, which is a parent solvent for phenol derivatives and is a poor solvent for lignophenol, solubilizes unreacted phenol derivatives and phenol derivatives for lignophenol extraction in large excess, Recover phenol as an insoluble fraction. In the phase separation system conversion system, some of the carbohydrates that have affinity for lignin centered on hemicellulose are contained in the phenol phase (see Non-Patent Document 3), and the insoluble fraction recovered by the primary purification is extracted with acetone. And a small amount of carbohydrate needs to be removed. Furthermore, secondary purification was performed to remove phenol derivatives that could not be removed by primary purification.

(Secondary purification)
By adding the extracted lignophenolacetone solution again to diethyl ether, diisopropyl ether, n-hexane or the like, the purified lignophenol can be recovered.

  The lignophenol obtained by the conventional primary purification or secondary purification was a polymer lignophenol.

Japanese Patent Laid-Open No. 02-233701 Japanese Patent Application Laid-Open No. 2004-115736 Japanese Patent Laid-Open No. 2004-137347 M. Funaoka and I. Abe, Tappi Journal, 72 (1989) 145 M. Funaoka, Polymer International, 47 (1998) 277 K. Mikame and M. Funaoka, Polymer Journal, 38 (2006) 694

However, the conventional lignophenol production method requires 15 to 20 times the amount of diethyl ether and n-hexane for the phenol derivative and the amount of acetone as the parent solvent of lignophenol for both primary and secondary purification. The manufacturing cost was high.
Furthermore, although the conventional method for purifying lignophenol can obtain high molecular weight lignophenol, it has not been able to efficiently produce low molecular weight lignophenol.

In view of the above problems, an object of the present invention is to provide a method for producing lignophenol and a method for producing lignophenol having a molecular weight of 400 to 1500 .

As a result of extensive research, the inventors of the present invention dripped a solution of a phenol containing lignophenol or a lignophenol in a parent solvent such as acetone into a poor lignophenol solvent such as diethyl ether to precipitate lignophenol. The present inventors have found that it is difficult to form agglomerates by irradiating ultrasonic waves during separation, and that the concentration of the lignophenol solution can be increased and the dropping speed can be increased.

In order to achieve the above object, a method for producing lignophenol of the present invention comprises a step of extracting a phase comprising phenols containing lignophenol from a lignocellulosic material as a starting material, and a phenol containing lignophenol. And a step of separating the crude lignophenol by adding the phase to the poor solvent, and irradiating the poor solvent with ultrasonic waves in the separation step.
Another method for producing lignophenol of the present invention includes a step of extracting crude lignophenol from a lignocellulosic material as a starting material, a step of adding crude lignophenol to a parent solvent to form a solution, and converting the solution into a poor solvent. And a step of separating lignophenol and irradiating the poor solvent with ultrasonic waves in the separation step.
In any of the above configurations, high molecular weight lignophenol can be efficiently produced by irradiating the poor solvent with ultrasonic waves.

In the above configuration, the low-molecular-weight lignophenol having a molecular weight of 400 to 1500 can be produced from the poor-solvent residual solution in the separation step by introducing the poor-solvent residual solution in the separation step into a nonpolar solvent under ultrasonic irradiation .

  In the above configuration, the nonpolar solvent is preferably irradiated with ultrasonic waves. By irradiating the nonpolar solvent with ultrasonic waves, low molecular weight lignophenol can be produced more efficiently.

The parent solvent may be any one of acetone, tetrahydrofuran, methanol, ethanol, dioxane, methyl cellosolve, dimethyl sulfoxide, dimethylformamide, or a mixed solvent in which these solvents are combined.
As a poor solvent, any one of diethyl ether, diisopropyl ether, n-hexane, cyclohexane, benzene, toluene, xylene, cyclopentyl methyl ether, tert-butyl methyl ether, ethyl acetate, chloroform, dichloromethane or a combination of these solvents Mixed solvents are preferred.
The nonpolar solvent is preferably n-hexane or cyclohexane.
By irradiating the poor solvent with ultrasonic waves, lignophenol can be produced efficiently and continuously.

According to the present invention, mass production of lignophenol with less impurities can be achieved industrially at low cost. Furthermore, a process for producing lignophenol having a molecular weight of 400 to 1500 has also been established , and the ripple effect such as expansion of the use of both is very great.

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 according to an embodiment of the present invention. In the figure, the starting material 1 is a lignocellulosic material. The lignocellulosic material is a general term for materials such as wood and grass, as well as waste wood and building waste.
As shown in the figure, the first step is a step in which the lignocellulosic material used as the starting material 1 is affinityd with liquid phenols to form an affinity solution.
The second step is a step of adding an acid to the affinity solution obtained in the first step and separating it into a phase 2 and an acid phase 3 made of phenols containing lignophenol.
In the third step, the phase 2 composed of the phenols containing lignophenol obtained in the second step is added to the poor solvent, and the precipitate (insoluble section) that precipitates in the poor solvent is converted into the crude lignophenol 4 and the phenols 5. It is a process of separating. In this separation step, it is preferable to irradiate ultrasonic waves.

The lignocellulosic material used as the starting material 1 will be described.
Lignocellulose 1 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% carbohydrates and about 30% hard sites of lignin. 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 3-position of the phenyl moiety of the phenylpropane structure. Broad-leaved trees have a syringyl type with a methoxyl group at 50:50 at the 3rd and 5th positions of the phenyl portion simultaneously with 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, an inter-unit bond is formed from the 5-position of the phenyl portion of the guaiacyl group. 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 in softwood, it begins to flow at about 170 ° C., whereas in hardwood it is about 140 ° C. Structural analysis by NMR (nuclear magnetic resonance apparatus) or FT-IR (Fourier transform infrared spectrometer) 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 second step of the production method of the present invention, the lignocellulose as the starting material 1 is solvated with phenols and the like, and this is extracted with a phase separation system conversion system in which it is phenolized by an interfacial reaction with concentrated acid. Yes (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 of FIG. 2, lignin 10 is converted into a phenol-substituted product using p (para) -cresol, reacted with sulfuric acid (H ₂ SO ₄ ), and a phase comprising p-cresol-type lignophenol 12 as a starting material. And a phase composed of water-soluble carbohydrates (saccharides), that is, an acid phase.

  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 based 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.

  As the acid to be brought into contact with lignocellulose 1, various inorganic acids and organic acids can be used as long as lignophenol or a lignin derivative that is a derivative thereof can be produced. As the inorganic acid, any of sulfuric acid, phosphoric acid, hydrochloric acid and the like can be used. As the organic acid, p-toluenesulfonic acid, trifluoroacetic acid, trichloroacetic acid, formic acid and the like can be used. When a lignocellulosic material is used as the lignin-containing material, it preferably has an action of swelling cellulose.

  As the inorganic acid, 65% by weight or more of sulfuric acid (preferably 72% by weight of sulfuric acid), 85% by weight or more of phosphoric acid, 38% by weight or more of hydrochloric acid, p-toluenesulfonic acid, trifluoroacetic acid, trichloroacetic acid, Examples include formic acid. The preferred acid is 85% by weight or more (preferably 95% by weight or more) phosphoric acid, trifluoroacetic acid or formic acid. In order to obtain a lignin derivative with a high yield, 65% by weight or more of sulfuric acid (especially 72% by weight of sulfuric acid) is preferable.

  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, lignophenol is not only lignophenol obtained by the reaction explained in FIG. 2, but lignophenol obtained by physical treatment such as heat from this simple lignophenol, a complex of simple lignophenol and cellulose, simple substance A complex of lignophenol and a synthetic polymer, a simple derivative of simple lignophenol, a higher-order phenol introduction of simple lignophenol, or a stable complex-like complex of simple lignophenol and a metal compound can be used. The above lignophenol other than lignophenol alone will be referred to as a lignophenol derivative. The lignophenol in the present invention includes a simple lignophenol and a lignophenol derivative.

  As the poor solvent used in the third step, in consideration of the use and recovery step, the affinity for lignophenol is also taken into consideration, and diethyl ether, diisopropyl ether (hereinafter referred to as IPE as appropriate), n-hexane, cyclohexane, and benzene. , Toluene, xylene, cyclopentyl methyl ether, tert-butyl methyl ether, ethyl acetate, chloroform, dichloromethane, or a mixed solvent obtained by combining these solvents.

  The input amount of the phase 2 made of phenol containing lignophenol into the poor solvent may be about 3 to 20% by weight. If the amount is outside this range, the lignophenol solubility is increased by the influence of the parent solvent, and the precipitation thereof is difficult to occur.

The purity of the crude lignophenol 4 obtained in the third step can be improved by carrying out a washing step. The washing step can be performed by adding and mixing a washing organic solvent to the precipitate collected in the third step, and then performing solid-liquid separation. Crude lignophenol 4 and lignin derivatives are distributed to the insoluble section as precipitates. Also in this step, when ultrasonic irradiation is performed, dispersibility is improved, and the number of washings can be reduced.
Here, as the organic solvent for washing, one or two or more selected from diethyl ether, diisopropyl ether, n-hexane, cyclohexane, benzene, toluene and xylene can be used.

  The method for producing lignophenol of the present invention is to irradiate the poor solvent used in the third step with ultrasonic waves. When the phase 2 consisting of phenols containing lignophenol is added to the poor solvent, this phase is used. It is preferable to add 2 to an excess poor solvent by dropping or the like and mix. The volume ratio of the poor solvent to the phase 2 composed of phenols containing lignophenol is required to be 15 times or more when there is no ultrasonic irradiation, but about 5 to 15 times is sufficient when ultrasonic irradiation is performed.

  Moreover, when irradiating with an ultrasonic wave at the time of dripping, it is preferable to avoid generation | occurrence | production of mixing heat in order to prevent the raise of the solubility to a poor solvent and to ensure a yield. For this reason, it is preferable to carry out the cooling while cooling the poor solvent to about 0 ° C to 20 ° C, preferably 0 ° C to 10 ° C.

  When ultrasonic irradiation was performed, the dispersibility of the lignin derivative was improved, and it was possible to increase the dropping speed to 60 times or more of the case without irradiation. Furthermore, it is possible to increase the concentration of a solution in which phase 2 composed of phenols containing lignophenol in a parent solvent such as acetone can be increased to 10 times or more, and flammability such as diethyl ether, n-hexane, IPE and the like. It is possible to significantly reduce the amount of high-boiling low-boiling organic solvents used. When ultrasonic irradiation is performed in this third step, the extraction effect of crude lignophenol is promoted, and the extraction time can be shortened.

A second embodiment of the method for producing lignophenol of the present invention will be described.
FIG. 3 is a process chart showing the production method of the second embodiment of lignophenol of the present invention. In the figure, the starting material 1 is a lignocellulosic material. As shown in the figure, step 1A is a step in which a solvent in which solid or liquid phenols are dissolved is infiltrated into lignocellulosic material 1 as a starting material. Then, the solvent is distilled off in step 1B.
The second step is a step of adding an acid to the lignocellulosic material adsorbed with the phenols obtained in the first A and 1B steps. By this second step, lignophenol is obtained as a mixture 6 with acid.
In the second step A, water is added to the mixture 6 obtained by the acid treatment in the second step to obtain a precipitate 8 composed of crude lignophenol 4 and a high molecular weight carbohydrate. In the second step A, water may be irradiated with ultrasonic waves, and the dispersibility of the crude lignophenol 4, which is a section that is not soluble in water, is improved, resulting in an effect of promoting the deoxidation effect.

  Further, by adding a step of washing and drying the precipitate 8 composed of the crude lignophenol 4 and the high molecular weight carbohydrate, the crude lignophenol 4 can be obtained efficiently (step surrounded by a dotted line in FIG. 3). . In other words, the precipitate 8 composed of the crude lignophenol 4 and the high molecular weight carbohydrate can be added to water to obtain the crude lignophenol and lignin derivative sections as insoluble sections. Although an organic solvent can be used instead of water, water is preferred in terms of removing the acid used.

The fourth step is a step of dissolving the crude lignophenol 4 obtained in the second A step in a parent solvent to obtain a crude lignophenol solution.
The parent solvent used here may be anything as long as it dissolves crude lignophenol 4 and does not dissolve carbohydrates. However, any one solvent of methanol, ethanol, acetone, methyl ethyl ketone, dioxane, pyridine, tetrahydrofuran, dimethylformamide or A mixed solvent composed of two or more of these can be used.

  The fifth step is a step of adding the crude lignophenol solution to the poor solvent and separating the precipitate (insoluble section) that precipitates in the poor solvent as purified purified lignophenol 7. This step is the same as the third step described in FIG. 1, and the poor solvent may be the same. Also in this separation step, it is preferable to irradiate ultrasonic waves.

  The purified lignophenol 7 obtained in the fifth step can improve the degree of purification by performing the washing step described in the production method of FIG. The purified lignophenol 7 has a high molecular weight lignophenol as a main component, and phenols are further removed from the crude lignophenol 4.

A third embodiment of the method for producing lignophenol of the present invention will be described.
FIG. 4 is a process chart showing the production method of the third embodiment of lignophenol of the present invention. In the figure, the steps up to the second step are the same as the manufacturing steps shown in FIG. After the acid addition in the second step, an inert hydrophobic organic solvent is added in the second B step. As the hydrophobic organic solvent, benzene, xylene, toluene, hexane, or a mixed solvent thereof can be used.
Next, centrifugation is performed in step 2C to extract the intermediate layer. This intermediate layer is in a state where crude lignophenol 4 and unreacted phenols and acids coexist.

  The 2D step is a step of adding crude lignophenol 4 as a precipitate by adding water to the intermediate layer. Furthermore, this crude lignophenol 4 can be added to water to obtain an insoluble fraction, thereby obtaining a crude lignin derivative category. Although an organic solvent can be used instead of water, water is preferred in terms of removing the acid used. In the second step D, water may be irradiated with ultrasonic waves, and the dispersibility of the crude lignophenol 4, which is a section that is insoluble in water, is improved, and the deoxidation effect is promoted.

  The fourth step is a step in which the crude lignophenol 4 obtained in the 2D step is dissolved in a parent solvent to obtain a crude lignophenol solution, and carbohydrates and the like in the solvent remain as precipitates. This fourth step is the same as step 4 described in FIG. 3, and the same parent solvent may be used. In the fourth step, when the crude lignophenol solution is irradiated with ultrasonic waves, the extraction effect of the crude lignophenol 4 is promoted, and the extraction time can be shortened. Furthermore, the extracted crude lignophenol liquid can be separated by solid-liquid separation means such as centrifugation or filtration.

  The solid content which is a precipitate can be further washed with a solvent capable of extracting the crude lignophenol 4 to recover the crude lignophenol 4 mixed with the solid content. In this case, the solid-liquid separation means can be sufficiently achieved by filtration.

  The fifth step is a step of separating the purified lignophenol 7 from the solution by adding the crude lignophenol solution to the poor solvent. Also in this separation step, it is preferable to irradiate ultrasonic waves. This fifth step is the same as the fifth step described in FIG. 3, and the same poor solvent may be used.

  The purified lignophenol 7 obtained in the fifth step can improve the degree of purification by performing the washing step described in the production method of FIG. The purified lignophenol 7 has a high molecular weight lignophenol as a main component, and phenols are further removed from the crude lignophenol 4.

According to the method for producing lignophenol of the first to third embodiments, lignophenol having a relatively large molecular weight can be efficiently precipitated. Furthermore, it has been found that the poor solvent, which is the residual liquid after depositing lignophenol, contains low molecular weight lignophenol, which has been difficult to obtain efficiently in the past. This low molecular weight lignophenol has a molecular weight of 400-1500 and a weight average molecular weight (Mw) of around 1000.

A method for recovering the low molecular weight lignophenol contained in the residual liquid of the poor solvent will be described.
FIG. 5 is a process diagram for explaining the production method for recovering the low molecular weight lignophenol of the present invention.
As the sixth step, the low-molecular weight lignophenol 9 can be obtained as a precipitate by adding the residual liquid of the poor solvent extracted with lignophenol to the poor solvent in which the low-molecular weight lignophenol is difficult to dissolve. Even in this sixth step, irradiation with ultrasonic waves has a great effect on improving the dispersibility of the low molecular weight lignophenol 9, removing impurities, and improving the acquisition rate.

  The extraction step of the low molecular weight lignophenol 9 can be performed as a single step by collecting the residual liquid of the poor solvent from which the lignophenol has been extracted.

  Furthermore, you may perform as a process which added the 6th process using the 3rd process shown in FIG. 1, and the 5th process of FIG. According to these steps, purified lignophenol 7 having a large molecular weight is recovered from the first poor solvent (the third step in FIG. 1 and the fifth step in FIGS. 3 and 4), and in the sixth step, it is recovered from the first poor solvent. Lignophenol 9 having a low molecular weight that could not be recovered can be recovered. That is, lignophenols 7 and 9 having different molecular weights can be separated and recovered in a series of steps.

  The high molecular weight lignophenol 7 produced according to the present invention, that is, the high molecular weight lignophenol is used for a high molecular weight by direct use as a polymer for a molded article or by hydroxymethylation for the purpose of forming a resol type phenol resin. Examples of the prepolymer use for derivatization and prepolymer use such as urethanization and epoxidation for the purpose of plasticization.

  Low molecular weight lignophenol 9 should be used as a material for pharmaceutical applications such as virus inhibitors and antiallergens, UV absorbers for plastics, additives such as plasticizers, and electronic applications such as photosensitizers for photochemical batteries. Can do.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not restrict | limited to these Examples.
Lignophenol was produced by the production method shown in FIG. To 1 g of spruce defatted wood flour, 10 cm ³ of p-cresol was added, 20 cm ³ of sulfuric acid (H ₂ SO ₄ , 72%) was added thereto, and the mixture was vigorously stirred. After stirring for 60 minutes, the mixture was separated into a p-cresol phase and a sulfuric acid phase by centrifugation.

  Next, the p-cresol phase was dripped at high speed into the poor solvent IPE in 30 seconds using a dropping column. During high-speed dropping, the IPE was subjected to ultrasonic irradiation with an ultrasonic generator (USS-1, Ultrasonic Stirrer, manufactured by Nippon Seiki Seisakusyo Co., Ltd.), and insoluble sections were collected. The frequency of the ultrasonic wave is 40 kHz, and its output is 35 W.

  Next, insoluble sections were extracted with acetone, and the acetone solution was filtered to obtain crude lignophenol 4 of Example 1.

(Comparative Example 1)
Next, as a comparative example of Example 1, lignophenol of Comparative Example 1 was prepared in the same manner as in Example 1 except that high-speed (30 seconds) dropwise addition to the IPE of the p-cresol phase was performed without ultrasonic irradiation. Extracted.

(Comparative Example 2)
As a comparative example of Example 1, the lignophenol of Comparative Example 1 was prepared in the same manner as in Example 1 except that the p-cresol phase was added dropwise to the IPE for 15 minutes without ultrasonic irradiation. Extracted.

  The crude lignophenol 4 extracted in Example 1 and Comparative Examples 1 and 2 was analyzed by gel permeation chromatography (GPC), and the residual amount of p-cresol was compared.

The analysis conditions for GPC are as follows.
(GPC conditions)
Column: Shodex KF-801, KF-802, KF-803, KF-804 (inner diameter 8.0mm, length 30cm)
Eluent: Tetrahydrofuran (THF), Flow rate: 1.0 cm ³ / min Temperature: 40 ° C
Detection wavelength: 280 nm
Standard polystyrene (weight average molecular weight (Mw) = 196000, 76600, 28500, 13100, 9860, 7000, 5000, 2960, 1270, 682, 578, 474, 370, 266, 162), p-cresol (Mw = 108)

FIG. 6 is a graph showing measurement results of gel permeation chromatography of lignophenol obtained in Example 1 and Comparative Examples 1 and 2. In FIG. 6, the horizontal axis represents elution time (minutes), and the vertical axis represents signal intensity (mV).
As is clear from FIG. 6, in the case of Comparative Example 1 in which the amount of p-cresol seen in the vicinity of 40 minutes after the start of elution is high-speed dripped without ultrasonic irradiation when the high-speed dropping is performed under the ultrasonic irradiation of Example 1. It turned out to be less.

  The molecular weight distribution of lignophenol of Example 1 was almost the same as that of Comparative Example 2 in which low-speed dropping was performed without ordinary ultrasonic irradiation. Thereby, it turned out that the removal effect of p-cresol is accelerated | stimulated by the ultrasonic irradiation used in Example 1. FIG. That is, in the case of Example 1, the dropping time required for 15 minutes without ultrasonic irradiation in Comparative Example 2 could be performed in 30 seconds, and the dropping speed could be increased 30 times.

The purified lignophenol 4 of Example 2 was extracted from 1000 g of cedar defatted wood flour whose lignin content was quantified by the Klason method in advance by the production method shown in FIG.
First, p-cresol corresponding to 3 times the molar amount of lignin content was sorbed together with acetone solvent to 1000 g of cedar defatted wood flour. After distilling off acetone, 72% sulfuric acid was added, and the mixture was vigorously stirred in a 30 ° C. water bath. After stirring for 1 hour, the reaction solution was dispersed in 10 times the amount of water. The insoluble fraction was recovered from the suspension by centrifugation, and the insoluble matter was suspended in water again and washed until the supernatant became neutral by centrifugation. This insoluble fraction was freeze-dried and then dried under reduced pressure in the presence of P ₂ O ₅ to obtain crude lignocresol, ie, crude lignophenol 4.

Next, unpurified lignocresol 4 was dissolved in acetone as a parent solvent, and the solid content was 30 mg / cm ³ , 50 mg / cm ³ , 100 mg / cm ³ , 150 mg / cm ³ , 200 mg / cm ³ , 300 mg / cm ³ . A lignocresol acetone solution was prepared.
Each solution 5 cm ^3, with a dropping column, was added dropwise to IPE75cm ³ is a poor solvent. The poor solvent, IPE, was irradiated with ultrasonic waves and dropped at a high speed of 10 seconds and 10 minutes at a time, thereby obtaining purified lignocresol 7 of Example 2 as an insoluble section.

(Comparative Example 3)
As a comparative example of Example 2, the purified lignocresol of the comparative example was extracted in the same manner as in Example 2 without ultrasonic irradiation.

  The purified lignocresol 7 recovered in Example 2 and Comparative Example 3 was subjected to GPC analysis, and the residual amount of p-cresol and the molecular weight distribution were compared.

FIG. 7 is a graph showing the results of gel permeation chromatography of lignophenol obtained in Example 2 and Comparative Example 3. In FIG. 7, the horizontal axis represents the elution time (minutes) and the vertical axis represents the signal intensity (mV). In the figure, the measurement result of crude lignophenol is also shown.
As is apparent from FIG. 7, in Example 2, when 200 mg / cm ³ of unpurified lignophenolacetone solution was dripped at high speed under ultrasonic irradiation, the amount of p-cresol seen around 40 minutes after the start of elution However, unreacted p-cresol and lignin degradation products were removed in the same manner as in the case where the 30 mg / cm ³ unpurified lignophenolacetone solution of Comparative Example 3 was added dropwise at low speed (10 minutes) without ultrasonic irradiation.

In Comparative Example 3, when 150 mg / cm ³ of unpurified lignophenolacetone solution 5 cm ³ was dropped into 75 cm ³ IPE over 10 minutes, the brown acetone solution particles were dispersed in the IPE as it was. As shown in FIG. 7, in this case, it was found that unreacted p-cresol and lignin degradation products remained and were not removed.

Furthermore, in Example 2, when 30 mg / cm ³ of unpurified lignophenolacetone solution was added dropwise while sonicating at a low speed, a pale pink lignophenol precipitate was obtained. 100 mg / cm ³ , 150 mg / cm ³ , 200 mg / cm ³ of unpurified lignophenolacetone acetone solution 5 cm ³ was dripped in 10 seconds while irradiating with ultrasonic waves. As a result, the above unpurified lignophenolacetone acetone solution 30 mg / cm ³ was slowed down. In the same manner as in the case where the solution was dropped while being subjected to ultrasonic treatment, a light pink lignophenol precipitate was obtained. As a result of recovering these and GPC analysis, it was found that in each case, unreacted p-cresol and lignin degradation products were removed.

Table 1 shows the dispersibility of the purified lignocresol 7 of Example 2 and Comparative Example 3 in a poor solvent. As shown in Table 1, in the case of Example 2 where the ultrasonic wave irradiation, the concentration of the crude lignophenol is good in dispersibility in 30 to 200 mg / cm ^3, a portion at 300 mg / cm ³ aggregation did.

On the other hand, in the case of Comparative Example 3, the concentration of the unpurified lignophenolacetone solution is 30 mg / cm ³ and 50 mg / cm ³ , and the dispersibility is good only when the speed is low, and it is not dispersed under other conditions. Purified lignocresol was not obtained.

From the above results, it was found that in the case of Example 2, the dispersibility was improved by performing ultrasonic irradiation when dropping the unpurified lignophenolacetone solution concentration into the poor solvent. In Example 2, when the concentration of the unpurified lignophenolacetone solution is 30 mg / cm ³ , the purification effect similar to that of the slow dropping of Comparative Example 3 can be obtained by applying high speed, so the purification speed is increased by 60 times. It was possible. Further, the concentration of the acetone solution can be increased by 6.7 times, and the amount of the low-boiling organic solvent having high flammability such as diethyl ether, n-hexane, IPE and the like can be greatly reduced.

To 1 g of spruce defatted wood flour, 10 cm ³ of p-cresol was added, and 20 cm ³ of 72% H ₂ SO ₄ was added thereto and stirred vigorously. After stirring for 60 minutes, the phases were separated into a p-cresol phase and an H ₂ SO ₄ phase by centrifugation. The p-cresol phase was dropped into 200 cm ^{3 of} n-hexane with a dropping column under ultrasonic irradiation, and the precipitation section was separated by filtration. This treatment removed unreacted phenol and insolubilized the low molecular weight segment of several hundred molecular weight together with the polymer segment.

The insoluble fraction was dissolved in acetone and then added dropwise to diethyl ether using a dropping column under ultrasonic irradiation. The filtrate was concentrated with an evaporator and then dropped into 100 cm ^{3 of} n-hexane for 30 seconds under ultrasonic irradiation, and the deposited precipitate was collected by filtration and washed twice with 20 cm ³ of n-hexane. The solid obtained after drying was 0.2 g. When analyzed by GPC, it was found to be a low molecular weight lignophenol 9 having a distribution of Mw = 400 to 1500.

  According to the present invention, by using ultrasonic irradiation in the separation, recovery, and purification steps, the amount of organic solvent that may be flammable can be greatly reduced, the processing time is shortened, and the manufacturing equipment is also downsized. This enables mass production of high quality high molecular weight lignophenol at low cost. In addition, low-molecular-weight lignophenol that can be expected for high value-added applications can be mass-produced.

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 manufacturing method of 2nd Embodiment of lignophenol of this invention. It is process drawing which shows the manufacturing method of 3rd Embodiment of lignophenol of this invention. It is process drawing explaining the method to manufacture the low molecular weight 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 Examples 1 and 2. It is a figure which shows the measurement result of the gel permeation chromatography of the lignophenol obtained in Example 2 and Comparative Example 3.

Explanation of symbols

1: Starting material (lignocellulosic material)
2: Phase consisting of phenols containing lignophenol 3: Acid phase 4: Crude lignophenol 5: Phenols 6: Mixture of lignophenol and acid 7: Purified lignophenol 8: Consisting of crude lignophenol and polymeric carbohydrate Precipitate 9: low molecular weight lignophenol 10: lignin 12: p-cresol type lignophenol

Claims (7)

Extracting a phase composed of phenols containing lignophenol from a lignocellulosic material as a starting material;
Adding a phase comprising phenols containing the above lignophenol to a poor solvent to separate the crude lignophenol,
A method for producing lignophenol, wherein the poor solvent is irradiated with ultrasonic waves in the separation step. A step of extracting crude lignophenol from the lignocellulosic material as a starting material;
Adding the crude lignophenol to a parent solvent to form a solution;
Adding the above solution to a poor solvent and separating the lignophenol,
A method for producing lignophenol, wherein the poor solvent is irradiated with ultrasonic waves in the separation step.   The method for producing lignophenol according to claim 1 or 2, wherein the amount of the poor solvent is 5 to 15 times the amount of the parent solvent. The poor solvent is one of diethyl ether, diisopropyl ether, n-hexane, cyclohexane, benzene, toluene, xylene, cyclopentyl methyl ether, tert-butyl methyl ether, ethyl acetate, chloroform, dichloromethane, or a solvent thereof. The method for producing lignophenol according to any one of claims 1 to 3 , wherein the mixed solvent is a combined solvent. A step of extracting crude lignophenol from the lignocellulosic material as a starting material;
Adding the crude lignophenol to a parent solvent to form a solution;
Adding the above solution to a poor solvent under ultrasonic irradiation to separate lignophenol ;
The poor solvent residual liquid separation step under microwave irradiation, a process you added to the nonpolar solvent, wherein the Ru with the method of the lignophenol from molecular weight 400 1500. The method for producing lignophenol having a molecular weight of 400 to 1500 according to claim 5, wherein the nonpolar solvent is n-hexane . The method for producing lignophenol having a molecular weight of 400 to 1500 according to claim 5, wherein the poor solvent is diisopropyl ether and the nonpolar solvent is n-hexane.

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