JP5338792B2 - Method for producing lignin derivative and method for producing lignin secondary derivative - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lignin derivative which includes phenolic hydroxide groups at a high rate and to which a reactive group is easily introduced and to provide a lignin secondary derivative to which the reactive group useful as a resin material is introduced and whose high crosslinking density can be expected. <P>SOLUTION: The lignin derivative is obtained by decomposing biomass, wherein a mole ratio of phenolic hydroxide groups to alcoholic hydroxide groups is 9:1 to 8:2. The lignin derivative has a number average molecular weight of 300 to 2,000 expressed in terms of polystyrene measured by gel permeation chromatography. The lignin secondary derivative is formed by introducing the reactive group to the lignin derivative. The reactive group is an epoxy group. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a method for producing a lignin derivative and a method for producing a lignin secondary derivative.

  Lignin, which is contained in about 30% of general wood components, is a substance that is abundantly biosynthesized after cellulose, but an effective utilization method has not been established. Lignin has a structure containing abundant aromatic rings, phenolic hydroxyl groups, and alcoholic hydroxyl groups, and a resin raw material can be considered as one of effective utilization methods (see, for example, Patent Document 1). When a functional group for crosslinking such as an epoxy group is introduced into lignin as the resin raw material, an alcoholic hydroxyl group having low reactivity in lignin inhibits the introduction of the functional group. According to the report by Tsujioka et al., The molar ratio of the phenolic hydroxyl group to the alcoholic hydroxyl group is about 0.8: 1.0 to 1.5: 1.0 (see, for example, Non-Patent Document 1). In addition, when a functional group for crosslinking such as an epoxy group is introduced into lignin, the alcoholic OH group is inferior in reactivity, so that it is necessary to introduce a phenol compound beforehand. Hasegawa et al. Are investigating epoxidation of lignophenol, but despite the increase in phenolic OH groups, there is a problem that the introduction rate of epoxy groups is reduced to around 20% (for example, non-patented). Reference 2).

JP 2001-261839 A

K. Mikame, M.M. Funaoka, Polym. J. et al. , 38, 585-591, 2006J . Kadota, K .; Hasegawa, M.M. Funoka Journal of Network Polymer. Japan, 27, 118-125, 2006

  The present invention provides a method for reliably producing a lignin derivative containing a large proportion of a phenolic hydroxyl group and in which a reactive group can be easily introduced. In addition, the present invention provides a method for reliably producing a lignin secondary derivative in which a reactive group useful as a resin raw material is introduced and a high crosslinking density can be expected.

As a result of intensive studies to achieve the above-mentioned problems, the present inventors have found that the phenolic hydroxyl group in the lignin and the alcoholic hydroxyl group contain a large proportion of the phenolic hydroxyl group within a specific molar ratio. In addition to finding out that the introduction of a sex group can be facilitated, a method for reliably producing such a lignin derivative has been found, and the present invention has been completed.
Such an object is achieved by the present inventions (1) to (6) below.
(1) A method for producing a lignin derivative obtained by decomposing biomass,
A decomposition step in which biomass is placed in the presence of water, and these are decomposed at a treatment temperature of 150 to 400 ° C. and a treatment pressure of 1.0 to 40 MPa at a high temperature and high pressure for a treatment time of 480 minutes or less ;
An immersion step of immersing the insoluble matter in the processed product obtained by the decomposition step in a solvent in which lignin is soluble;
A distillation step of distilling off the solvent in which the lignin is soluble from the soluble matter in the treated product obtained by the immersion step,
A method for producing a lignin derivative comprising obtaining a lignin derivative containing a phenolic hydroxyl group and an alcoholic hydroxyl group in a molar ratio of 9: 1 to 8: 2.
(2) The said decomposition process is a manufacturing method of the lignin derivative as described in said (1) performed while stirring the said biomass .
(3) The said lignin derivative is a manufacturing method of the lignin derivative as described in said (1) or (2) whose polystyrene conversion number average molecular weights measured by the gel permeation chromatography are 300-2,000.
(4) The said biomass is a manufacturing method of the lignin derivative in any one of said (1) thru | or (3) which is a plant or plant-derived substance containing a lignin.
(5) A method for producing a lignin secondary derivative obtained by introducing a reactive group into a lignin derivative obtained by decomposing biomass,
A decomposition step in which biomass is placed in the presence of water, and these are decomposed at a treatment temperature of 150 to 400 ° C. and a treatment pressure of 1.0 to 40 MPa at a high temperature and high pressure for a treatment time of 480 minutes or less ;
An immersion step of immersing the insoluble matter in the processed product obtained by the decomposition step in a solvent in which lignin is soluble;
A distillation step for distilling off the solvent in which the lignin is soluble from the soluble matter in the treated product obtained by the immersion step;
A reactive group introduction step of mixing the treated product obtained by the distillation step and the compound containing the reactive group,
A lignin secondary derivative obtained by obtaining a lignin secondary derivative obtained by introducing the reactive group into a lignin derivative containing a phenolic hydroxyl group and an alcoholic hydroxyl group in a molar ratio of 9: 1 to 8: 2. Manufacturing method.
(6) The method for producing a lignin secondary derivative according to (5) , wherein the reactive group is an epoxy group.

  According to the present invention, it is possible to provide a method for reliably producing a lignin derivative that contains a large proportion of a phenolic hydroxyl group and is easy to introduce a reactive group, and that a reactive group useful as a resin raw material is introduced, A method of reliably producing a lignin secondary derivative that can be expected to have a high crosslinking density can be provided. By obtaining a lignin derivative having excellent curability and physical properties based on such a high crosslinking density and a secondary derivative thereof, an environmentally friendly and industrially useful resin can be provided.

  The lignin derivative in the present invention is obtained by decomposing biomass, and the lignin derivative has a phenolic hydroxyl group and an alcoholic hydroxyl group in a molar ratio of 9: 1 to 8: 2. And a lignin derivative. Both the phenolic hydroxyl group and the alcoholic hydroxyl group are mainly derived from a lignin skeleton, and according to the present invention, the phenolic hydroxyl group contains a large proportion of the molar ratio, and the reactive group can be easily introduced. It can be. Since many reactive groups can be introduced, it becomes possible to provide a resin having a high crosslink density. The method for producing a lignin derivative of the present invention is a method for producing such a lignin derivative.

  The biomass in the present invention is a plant containing lignin or a processed product of the plant. Examples of the plant include broad-leaved trees such as beech, birch and oak, conifers such as cedar, pine, and oak, and gramineous plants such as bamboo and rice straw. Examples of the shape of biomass used in the present invention include blocks, chips, and powders.

The lignin derivative in the present invention can be obtained by decomposing the biomass by high-temperature and high-pressure treatment in the presence of a solvent.
As a specific example of the method for producing a lignin derivative of the present invention, first, the biomass is adjusted to a certain size, and then this is put into a pressure vessel with a stirrer and a heating device together with a solvent, optionally a catalyst. The biomass is stirred while being heated and pressurized (decomposition step). Next, the contents of the pressure vessel are filtered to remove the filtrate, and the water-insoluble matter is washed and separated with water. Next, the water-insoluble matter is immersed in a solvent in which lignin is soluble (for example, acetone) (immersion step), the lignin derivative is extracted into acetone, and the acetone is distilled off (distillation step). A lignin derivative can be obtained.

  As a magnitude | size of the biomass in the said decomposition | disassembly process, about 100 micrometers-1 cm are preferable, and 200 micrometers-500 micrometers are more preferable. At this time, the shape of the biomass may be any of a block shape, a chip shape, a powder shape and the like as described above.

  Examples of the solvent in the decomposition treatment include water, alcohols such as methanol and ethanol, phenols such as phenol and cresol, ketones, ethers, and the like, and it is particularly preferable to use water. The amount of the solvent used is preferably as large as possible with respect to the biomass, but is preferably about 2 to 10 times the biomass weight, more preferably about 3 to 5 times the biomass weight. An inorganic base such as sodium carbonate may be added as a catalyst.

  As conditions for processing the biomass at high temperature and high pressure, the processing temperature is usually preferably 150 ° C to 400 ° C, more preferably 200 ° C to 380 ° C. The treatment temperature can be used outside the above range, but the molecular weight of the lignin derivative can be controlled by the treatment temperature, and tends to be a low molecular weight body when treated at a high temperature and a high molecular weight body when treated at a low temperature. The treatment time is usually preferably 0 minute to 480 minutes, and more preferably 30 minutes to 120 minutes. Although the treatment time can be used outside the above range, the OH equivalent of the lignin derivative can be controlled by the treatment time, and the OH equivalent tends to be large in the short-time treatment and small in the long-time treatment. The pressure is preferably 1.0 MPa to 40 MPa, more preferably 1.5 MPa to 25 MPa. The pressure can be used even outside the above range, but by treating at a higher pressure, an effect equivalent to that obtained when the treatment is performed for a long time can be obtained.

By treating the biomass under the conditions within the above range, the number average molecular weight is preferably in the range of about 300 to 2,000, and moreover, as the lignin derivative in the present invention, the OH equivalent is preferably about 100 to 200. It becomes easy to control to OH equivalent.
In the present invention, the OH equivalent and the molecular weight can be controlled independently. For example, a OH equivalent (mainly phenolic hydroxyl group) as large as about 200 can be obtained by short-time treatment regardless of the treatment temperature. Saturate at around 100 by long-time treatment to obtain a small OH equivalent.

  The lignin derivative obtained by the above decomposition is characterized by having a phenolic hydroxyl group and an alcoholic hydroxyl group in a molar ratio of 9: 1 to 8: 2. The lignin derivative preferably has a polystyrene-equivalent number average molecular weight of 300 to 2,000 as measured by gel permeation chromatography. However, if the functional group for crosslinking is introduced below 300, a monofunctional lignin secondary derivative may be formed and may not be cured. If it exceeds 2,000, the secondary lignin secondary There may be a problem that the softening point of the derivative is too high and molding becomes difficult.

  Moreover, this invention is a lignin secondary derivative which introduce | transduced the reactive group into the lignin derivative obtained above. A reactive group useful as such a lignin secondary derivative resin raw material is introduced, and a high crosslinking density can be expected.

  The reactive group in the lignin secondary derivative is a reactive group, the reactive group is self-reactive, two or more of the same reactive groups can react with each other, and other functional groups May be used as long as they can react with each other. Preferably, a vinyl group having a carbon-carbon unsaturated bond, similarly ethynyl group, maleimide group, and the like are exemplified by epoxy group, cyanate group, isocyanate group, etc. In particular, it is not limited to these. A particularly preferred reactive group is an epoxy group.

As a method for producing the lignin secondary derivative of the present invention, those skilled in the art can use a known method by which the reactive group can be introduced into the phenolic hydroxyl group, and the method for introducing the reactive group is appropriately selected. be able to.
Specific examples of each reactive group introduction method (reactive group introduction step) are shown below, but are not limited thereto.
For example, when an epoxy group is introduced, the lignin derivative is dissolved in epichlorohydrin, and a base catalyst such as NaOH is added under reflux under reduced pressure.
When a vinyl group is introduced, a halogen compound containing a vinyl group such as allyl halide or vinylbenzyl halide and the lignin derivative are dissolved in a solvent, and a base catalyst such as NaOH is added with heating and stirring. It is obtained by.
When introducing an ethynyl group, a halogen compound containing an ethynyl group such as propargyl halide or phenylacetylene and the lignin derivative are dissolved in a solvent, and a base catalyst such as NaOH is added under heating and stirring. can get.
Further, when a maleimide group is introduced, parachloronitrobenzene is reacted with the phenolic OH group of the lignin derivative to obtain a polynitrated lignin bonded through an ether bond. Subsequently, the polynitrated lignin is reduced to be converted to polyaminated lignin and reacted with maleic anhydride to obtain a lignin secondary derivative having a maleimide group.
When a cyanate group is introduced, the lignin derivative and the halogenated cyanate are dissolved in a solvent, and a base catalyst such as NaOH is added under heating and stirring.
Moreover, when introducing an isocyanate group, it is obtained by treating lignin with maleic anhydride to convert the OH group of lignin to a carboxyl group and heating in the presence of diphenylphosphoric acid azide.

Since the lignin derivative in the present invention contains abundant phenolic OH groups, the lignin derivative is generally applicable to applications in which a phenol resin is conventionally used, and the lignin secondary derivative is a reactive group to be introduced. Thus, for example, it can be applied to various uses including an epoxy resin. Furthermore, since it contains abundant phenolic OH groups as compared with conventional lignin derivatives, it is possible to increase the crosslinking density when the lignin secondary derivative is cured after secondary derivatization.
Specific examples of such applications include molding materials, sealing materials, laminates, and FRP resins used for automobiles, electrical components, electronic components, and semiconductors.
In actual use, the lignin derivative can be used alone for a phenol resin, or can be used in combination with another phenol resin.

Moreover, in the lignin secondary derivative, when an epoxy group is introduced as the reactive group, it can be used as an epoxy resin, and the lignin derivative can be used as a curing agent for such a lignin secondary derivative. It is also possible to use a curing agent such as a phenolic resin or other phenolic resin, or an acid anhydride known to those skilled in the art, or to use it in combination with another epoxy resin.
Furthermore, when a vinyl group is introduced as the reactive group, it can be used as a curable resin such as a radical, a cation, and an anion. Further, as the reactive group, the ethynyl group, maleimide group, When a cyanate group, an isocyanate group, or the like is introduced, it can be used as a known resin having these reactive groups, and these resins can be used in the various applications.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, a reference example, and a comparative example, this invention is not limited to this.

Example 1
15 g of Soso bamboo powder (60 mesh under) and 80 g of pure water were introduced into a 300 ml autoclave, and the contents were treated at 8.0 MPa and 300 ° C. for 120 minutes with stirring at 300 rpm to decompose Soso bamboo. Subsequently, 10.0 g of water-insoluble parts were separated by filtering the decomposition product and washing with pure water. The water-insoluble part was immersed in 200 ml of acetone overnight and filtered to recover the acetone-soluble part. Subsequently, 2.7 g of lignin derivative was obtained by evaporating acetone from the acetone soluble part and then drying. About the thing obtained here, from the result measured by < ¹ > H-NMR, an aromatic ring is seen in 7-8 ppm, a methoxy group is observed in the vicinity of 3.5-4 ppm, and a peak of an alkyl group is seen over 0.5-3 ppm. It was confirmed to be a derivative.

The OH equivalent of the lignin derivative obtained above was determined by the following method. In a stoppered Erlenmeyer flask, 4.0 g of a mixed solution of acetic anhydride / pyridine (1/3 volume ratio) and 1.0 g of the lignin derivative obtained above were dissolved. After maintaining this solution at 60 ° C. for 3 hours, 1 ml of pure water was added. When the solution thus obtained was titrated with a 0.1 mol / L NaOH aqueous solution with pH = 10 as an end point, the OH equivalent of the lignin derivative was 118.
The molar ratio of phenolic OH groups to alcoholic OH groups in the lignin derivative obtained above (hereinafter referred to as P / A ratio) was determined by the following method. 1.0 g of the lignin derivative obtained above was acetylated using 4.0 g of an acetic anhydride / pyridine (1/3 volume ratio) mixed solution. From this reaction solution, unreacted acetic anhydride and pyridine were distilled off, and measurement was performed by ¹ H-NMR using an acetylated lignin derivative obtained by drying. From the integral ratio of protons derived from acetyl groups (derived from acetyl groups bonded to phenolic OH groups: 2.2 to 2.6 ppm, derived from acetyl groups bonded to alcoholic OH groups: 1.6 to 2.2 ppm), mol When the ratio was determined, the P / A ratio was 9.0: 1.0.
In addition, the molecular weight of the lignin derivative obtained above was measured by gel permeation chromatography in terms of polystyrene using tetrahydrofuran as an eluent. As a result, number average molecular weight (Mn) = 560, molecular weight distribution (Mw / Mn) = 1. 18

Example 2
In Example 1, except having changed process temperature 300 degreeC into 150 degreeC, it carried out similarly to Example 1 and obtained the lignin derivative 3.5g. The lignin derivative obtained here was evaluated in the same manner as in Example 1. As a result, OH equivalent = 122, P / A ratio = 8.8: 1.2, Mn = 1800, Mw / Mn = 1.82. there were.

Example 3
A lignin derivative 3.2 g was obtained in the same manner as in Example 1 except that the processing temperature 300 ° C. was changed to 200 ° C. and the processing pressure was changed from 8.0 MPa to 1.5 MPa. The lignin derivative obtained here was evaluated in the same manner as in Example 1. As a result, OH equivalent = 124, P / A ratio = 8.9: 1.1, Mn = 1000, Mw / Mn = 2.02. there were.

Example 4
In Example 1, except having changed the process temperature from 300 degreeC to 400 degreeC and the process pressure from 8.0MPa to 25MPa, it carried out similarly to Example 1 and obtained 2.1g of lignin derivatives. The lignin derivative obtained here was evaluated in the same manner as in Example 1. As a result, OH equivalent = 131, P / A ratio = 9.0: 1.0, Mn = 280, Mw / Mn = 1.80. there were.

Example 5
In Example 1, except having changed processing time 120 minutes into 30 minutes, it carried out similarly to Example 1 and obtained 3.2 g of lignin derivatives. The lignin derivative obtained here was evaluated in the same manner as in Example 1. As a result, OH equivalent = 202, P / A ratio = 8.9: 1.1, Mn = 620, Mw / Mn = 1.35. there were.

Example 6
In Example 1, except having changed processing time 120 minutes into 60 minutes, it carried out similarly to Example 1 and obtained 3.6 g of lignin derivatives. The lignin derivative obtained here was evaluated in the same manner as in Example 1. As a result, OH equivalent = 171, P / A ratio = 8.5: 1.5, Mn = 570, Mw / Mn = 1.24. there were.

Example 7
1.2 g of lignin derivative obtained in the same manner as in Example 1 and 100.0 g of epichlorohydrin were introduced into a 100 ml three-necked flask equipped with a stirrer, a cooler and a dropping funnel, and the pressure was 100 mmHg. Then, 2.0 g of a 20% strength aqueous NaOH solution was added dropwise over 30 minutes. Thereafter, the reaction mixture was obtained by maintaining the reduced-pressure reflux state for 90 minutes. In the reaction mixture, the insoluble part was removed by filtration, and the epichlorohydrin soluble part was isolated. Epichlorohydrin was distilled off from this epichlorohydrin soluble part and dried to obtain 0.8 g of a lignin secondary derivative (epoxidized lignin).
When the structure of the lignin secondary derivative obtained above was confirmed by ¹ H-NMR, in addition to the peak of the lignin derivative, 2.7, 2.9, 3.3, 3.5, and 3.9 ppm had an epoxy group. Origin peaks were observed.
The molecular weight of the lignin secondary derivative was Mn = 600 and Mw / Mn = 1.67 as measured by gel permeation chromatography in terms of polystyrene.
The epoxy group introduction rate of the lignin secondary derivative was 30% as measured by ¹ H-NMR.

Example 8
1.2 g of lignin derivative obtained in the same manner as in Example 1 and 100 ml of N, N′-dimethylformamide were introduced into a 100 ml three-necked flask equipped with a stirrer, a cooler, and a dropping funnel. An aqueous NaOH solution (2.0 g) was added and mixed. While heating and stirring this mixed solution at 60 ° C., 1.3 g of allyl bromide was added dropwise over 30 minutes, and stirring was further continued at 60 ° C. for 90 minutes to cause a reaction. After the reaction mixture was dissolved in methyl isobutyl ketone (MIBK), the MIBK solution was washed with water, and the solvent was distilled off and dried to obtain 0.8 g of a lignin secondary derivative (allylated lignin). The obtained lignin secondary derivative was evaluated in the same manner as in Example 7. As a result, Mn = 610 and the functional group introduction rate was 45%.

Reference example 1
In Example 1, except having changed the pure water of a solvent into phenol, it carried out similarly to Example 1 and obtained 5.2g of lignin derivatives. The lignin derivative obtained here was evaluated in the same manner as in Example 1. As a result, OH equivalent = 102, P / A ratio = 9.0: 1.0, Mn = 680, Mw / Mn = 1.53. there were.

Comparative Example 1
With reference to Non-Patent Document 1 (K. Mikame, M. Funoka, Polym. J., 38, 585-591, 2006J), lignophenol derivatives were synthesized by the following method. 10 g of Soso bamboo powder was placed in a 500 ml beaker, and an acetone solution of p-cresol (containing 3 moles of phenol derivative per lignin C9 unit) was added, stirred with a glass rod, and allowed to stand for 24 hours. Thereafter, acetone was completely distilled off to obtain p-cresol sorption wood flour. To this bamboo powder, 100 ml of 72 wt% sulfuric acid was added and stirred vigorously at 30 ° C. for 1 hour, and then the mixture was poured into a large excess of water. Undissolved sections were collected, deoxidized, dried, and ligno. A phenol derivative was obtained. When this lignophenol derivative was evaluated in the same manner as in Example 1, Mn = 3600, OH equivalent = 143 g / eq, and P / A ratio = 5.8: 4.2.

Comparative Example 2
The lignophenol derivative obtained in Comparative Example 1 was epoxidized by the following method with reference to Non-Patent Document 2 (Kadota, K. Hasegawa, M. Funoka Journal of Network Polymer. Japan, 27, 118-125, 2006). . Into a 100 ml three-necked flask equipped with a stirrer, a cooler and a dropping funnel, 1.4 g of the lignophenol derivative obtained in Comparative Example 1 and 100.0 g of epichlorohydrin were introduced and refluxed to 100 mmHg under reduced pressure. 1.0 g of 20% NaOH aqueous solution was added dropwise over 30 minutes. Thereafter, the vacuum reflux state was maintained for 90 minutes. The insoluble part was filtered off from the reaction mixture, and epichlorohydrin was distilled away from the epichlorohydrin soluble part and dried to obtain 1.3 g of epoxidized lignophenol. The obtained lignin secondary derivative was evaluated in the same manner as in Example 7. As a result, Mn = 2400 and the epoxy group introduction rate was 19%.

Claims (6)

A method for producing a lignin derivative obtained by decomposing biomass,
A decomposition step in which biomass is placed in the presence of water, and these are decomposed at a treatment temperature of 150 to 400 ° C. and a treatment pressure of 1.0 to 40 MPa at a high temperature and high pressure for a treatment time of 480 minutes or less ;
An immersion step of immersing the insoluble matter in the processed product obtained by the decomposition step in a solvent in which lignin is soluble;
A distillation step of distilling off the solvent in which the lignin is soluble from the soluble matter in the treated product obtained by the immersion step,
A method for producing a lignin derivative comprising obtaining a lignin derivative containing a phenolic hydroxyl group and an alcoholic hydroxyl group in a molar ratio of 9: 1 to 8: 2. The method for producing a lignin derivative according to claim 1, wherein the decomposition treatment is performed while stirring the biomass . The method for producing a lignin derivative according to claim 1 or 2 , wherein the lignin derivative has a polystyrene-equivalent number average molecular weight of 300 to 2,000 as measured by gel permeation chromatography. The method for producing a lignin derivative according to any one of claims 1 to 3 , wherein the biomass is a plant containing lignin or a plant-derived substance. A method for producing a lignin secondary derivative obtained by introducing a reactive group into a lignin derivative obtained by decomposing biomass,
A decomposition step in which biomass is placed in the presence of water, and these are decomposed at a treatment temperature of 150 to 400 ° C. and a treatment pressure of 1.0 to 40 MPa at a high temperature and high pressure for a treatment time of 480 minutes or less ;
An immersion step of immersing the insoluble matter in the processed product obtained by the decomposition step in a solvent in which lignin is soluble;
A distillation step for distilling off the solvent in which the lignin is soluble from the soluble matter in the treated product obtained by the immersion step;
A reactive group introduction step of mixing the treated product obtained by the distillation step and the compound containing the reactive group,
A lignin secondary derivative obtained by obtaining a lignin secondary derivative obtained by introducing the reactive group into a lignin derivative containing a phenolic hydroxyl group and an alcoholic hydroxyl group in a molar ratio of 9: 1 to 8: 2. Manufacturing method. The method for producing a lignin secondary derivative according to claim 5 , wherein the reactive group is an epoxy group.