Biomass treating method for treating biomass under supercritical or subcritical condition of alcohol using mixture solvent obtained by adding water to various aliphatic alcohol

According to the present invention, in a method of decomposing and liquefying biomass using a solvent in a supercritical or subcritical state, the decomposition and liquefaction can be easily controlled, and the supercritical product obtained by the decomposition and liquefaction can be easily selected. To subcritical solvent system. In the present invention, the treatment of alcohol under supercritical or subcritical conditions using a mixed solvent obtained by adding water to alcohol is defined as a temperature range of 100 ° C or more and 500 ° C or less and a pressure range of 1 MPa or more and 100 MPa or less. Means the treatment in the mixed solvent maintained at. Further, the water addition rate of 5 to 20% by volume means that the volume of the added water is 5 to 20 when the volume of the water / alcohol mixed solvent is 100.

The amount of various biomass generated including lignocellulosic biomass in Japan has reached about 370 million tons, of which about 77 million tons are discarded without being used, and its effective use is desired. Is done. Under these circumstances, many scientists and engineers are involved in the development of technology for recycling the biomass as useful products, especially fuels and chemical products. It is clear that the ultimate goal is to make the chemical substances and energy emitted to the environment purify by the power of nature, which will lead to the true maintenance of the stability of the global environment.

Under these circumstances, water, alcohol, etc. can be used as reaction and treatment solvents by relatively circulating them. Therefore, chemical systems using these solvents, especially those in the supercritical or subcritical state, are used. In a chemical system using conditions, the solvent is capable of constructing a unique reaction system in supercritical to subcritical, and has been studied in many chemical fields. In a chemical reaction system using water or an aliphatic alcohol in a supercritical or subcritical state, the aromatic compound contained in the plant and / or other components in the plant are easily dissolved and decomposed to decompose the aromatic compound. , Monosaccharides, polysaccharides, etc. can be liberated from the plant body, so that useful chemical products can be isolated from the liberated aromatic compounds, monosaccharides, polysaccharides, etc., or polymers thereof can be produced. Is known to be possible.

Furthermore, for systems that use supercritical or subcritical alcohol solvents, in the conversion of vegetable oil to biodiesel fuel by supercritical methanol, triglyceride, which is the main component of vegetable oil, is converted to methyl esterified product by transesterification reaction. , A technique for converting to diesel engine fuel has been reported (Non-Patent Document 1). In addition, the present inventor puts one or more selected from the group consisting of lignocellulosic biomass, cellulose-based biomass, nitrogen-containing polysaccharides and protein-based biomass in a supercritical or subcritical alcohol solvent. We have proposed a method for obtaining fuel, useful chemical products, etc. from the biomass by processing (Patent Document 1). However, in a treatment system such as biomass that uses water in the supercritical state, the reaction rate is very fast in milliseconds, which makes it difficult to control, and the problem of overdecomposition of the component to be treated and the solubilization efficiency are not good. There was a problem. In addition, in those using supercritical or subcritical alcohols, improvements are seen in the reaction rate, solubilization efficiency of the component to be treated, etc., but they are not yet sufficient, especially when supercritical methanol is used. There was a problem that the solubilization efficiency of the processing component was not good.

<patcit num="1"><text>Japanese Patent Application Laid-Open No. 2001-205070, in particular, claims</text></patcit><nplcit num="1"><text>Jasco Report "Supercritical Latest Technology Special Issue No. 3" JASCO Corporation, 28-31 (May 28, 1999), Application of supercritical fluids to post-petrochemistry</text></nplcit>

<p> The subject of the present invention is that the decomposition and solubilization of a system using an aliphatic alcohol solvent such as methanol in the supercritical state can be easily controlled, and the supercritical to subcritical products obtained accordingly have good selectivity. It is to provide a critical solvent system. If water is added to an aliphatic alcohol solvent such as methanol in order to solve the above problems, a high acid catalytic effect of supercritical to subcritical water can be expected, and more efficient solubilization of wood may be realized. I thought. Therefore, what kind of reaction system can be constructed when water is added to a system for treating biomass with alcohol in a supercritical or subcritical state is originally included in the case of positively adding water, that is, in biomass and the like. Considering the characteristics of the reaction system when more than the water brought into the system by water is added, the correlation between the amount of water added and the decomposition / solubilization characteristics of biomass is considered, and the amount of water added is 5 ~. It was found that the solvent function such as extremely remarkable solubilization efficiency was exhibited at 20% by volume, and the above-mentioned problems could be solved.</p>

<p> In the present invention, one or more selected from the group consisting of (1) lignocellulosic biomass, cellulose-based biomass, nitrogen-containing polysaccharides and protein-based biomass is added to an aliphatic alcohol having 1 to 8 carbon atoms. This is a method for decomposing and liquefying the biomass, which is treated under supercritical or subcritical conditions of alcohol using a mixed solvent containing ~ 20% by volume of water. Preferably, (2) the method for decomposing and liquefying biomass according to (1) above, wherein the maximum weight ratio of biomass and mixed solvent is 0.3 wt / wt, and more preferably, the biomass is lignocellulose-based biomass. The method for decomposing and liquefying biomass according to the above (1) or (2), more preferably (3) the above-mentioned (1), (2) or (3) in which the aliphatic alcohol is methanol. This is a method for decomposing and liquefying biomass.</p>

<p> As an effect of the invention, 5 to 20% by volume of water is added to a decomposition / solubilization treatment system using a supercritical to subcritical solvent of biomass, especially lignocellulose-based biomass, particularly an aliphatic alcohol-based solvent having 1 to 8 carbon atoms. It can be mentioned that the supercritical to subcritical solvent decomposition / solubilization treatment system having good solubilization efficiency and easy control could be provided by treating under the supercritical to subcritical conditions of alcohol. Conylferryl alcohol, sinapyl alcohol, and their γ-alkyl ethers are obtained in high yields, especially from lignocellulosic biomass, and sinapyl alcohol γ-methyl ether is 28.5 on a lignin basis, especially when methanol is used. It has the effect of being able to be collected by decomposition and dissolution in a high yield of% (7.6% on a wood basis).</p>

A, Fig. 1 shows that using beech wood flour as an example of biomass, the decomposition and solubilization characteristics when the amount of water added is changed under batch treatment conditions with a treatment temperature of 350 ° C and a treatment time of 5 minutes are insoluble. It is shown as a correlation of the amount of residue. However, the treatment pressure could not be controlled due to batch processing, and the pressure increased as the amount of water added increased, and was 43 MPa when no water was added and 100 MPa when 100% by volume of water was added. The effect of this difference in pressure is considered to be small. Without the addition of water, 62% beech wood flour was solubilized in methanol and 38% insoluble residue was recovered. On the other hand, when water was gradually added, the amount of insoluble residue decreased, and when the water content was 10% by volume, the amount of residue became the minimum, and nearly 100% of wood flour was solubilized. It is presumed that this is because the wood was decomposed more effectively due to the acid catalytic effect of supercritical or subcritical water. On the other hand, as the amount of water added increases, the dielectric constant of the water / methanol mixed solvent increases and the solubility decreases, so it is presumed that the amount of insoluble residue increases. From the above experiments, it was found that the addition of 10% by volume of water is optimal for solubilizing wood. This means that under the condition of a treatment temperature of 350 ° C as shown in Fig. 2, 30 minutes of treatment is required to solubilize 95% or more of wood without adding water, whereas 10% by volume of water is added. It is clear from the fact that solubilization is almost 100% completed in about 5 minutes. However, the treatment pressure was 43 MPa when no water was added and 50 MPa when 10% by volume of water was added. It can be easily inferred that the effect of adding water can be obtained even when other alcohols are used and applied to other biomass. As the biomass, it is preferable to use the biomass crushed so that the circumscribed diameter is 10 mm or less.

B. A chemical product obtained by treating beech wood flour as an example of biomass when water is not added and when 10% by volume of water is added, with a temperature condition of 270 ° C and a treatment time of 3 minutes. A comparison is shown in Table 1. However, the treatment pressure was 27 MPa when no water was added and 30 MPa when 10% by volume of water was added. It was found that useful chemical products can be obtained in high yield under mild treatment conditions.

<tables num="1"><img file="JP2005296906A_D0001.tif" /></tables>

C. In the experiment, a batch-type pressure-resistant 200 MPa reaction vessel was filled with biomass and water / alcohol, heated using a tin or oil bath that can be adjusted to 100 ° C to 500 ° C, and after a lapse of time. It was carried out by immersing it in a water bath at 20 ° C and quenching it to stop the reaction. Further, a salt bath [sodium sulfite, potassium sulfite (1: 1)] or the like can also be used as the heating bath. Coniferyl alcohol, sinapyl alcohol, p-kumalyl alcohol and their derivatives can be recovered as components derived from D. lignin. In addition, as components derived from cellulose and hemicellulose, serooligosaccharides and their methylated derivatives, saccharides such as glucose, xylose, mannose and fructose and their methylated derivatives, and levoglucosan, hydroxymethylfurfural, furfural and their derivatives are recovered as useful components. can do. E. Subcriticality is a condition in which the temperature of the reaction system is equal to or higher than the boiling point of water / alcohol and the pressure is higher than the vapor pressure of water / alcohol at the reaction temperature. In the mixed solvent of water / methanol, it depends on the mixing ratio. It refers to the conditions of a temperature range of 100 ° C to 374 ° C and a pressure range of 1MPa to 22MPa.

Hereinafter, the present invention will be specifically described with reference to Examples, but this is intended to make the present invention easier to understand, and it is natural that the present invention is not interpreted in a limited manner.

4.9 mL of water / methanol mixed solvent was sealed with 150 mg of beech wood flour in a 5 mL volume material Inconel-625 reaction tube, and the pressure was 27 to 100 MPa, the treatment temperature was 270 ° C and 350 ° C for 1 to 30 minutes, and the temperature was high and high pressure. Processing was performed. The water addition rate was changed in the range of 0 to 100% by volume. The obtained reaction product was filtered through a 0.2 μm membrane filter (manufactured by Advantex, trade name TO20A047A) and separated into an insoluble residue and a water / methanol soluble part. In addition, the contents of cellulose, hemicellulose and lignin in the insoluble residue were evaluated by the sulfuric acid method. The results are shown in FIGS. 3 and 4. The water / methanol soluble part is a high performance liquid chromatograph (HPLC) (manufactured by Shimadzu Corporation, column STR-ODSII, mobile phase water / methanol = 80/20 to 0/100 (60 minutes), temperature 40 ° C. , Detector SPD (280 nm)) and (column ULTRON PS-80P, mobile phase water, temperature 80 ° C, detector differential refractometer) to confirm the decomposition products. The results of lignin-derived products are shown in Table 2, and the results of cellulose-derived products are shown in Table 3. The beech wood powder used was crushed so that the circumscribed diameter was 280 μm or less. Figure 3 shows the correlation between the treatment time and the amount of residue when 10% by volume of water was added and when water was not added when the treatment temperature was 270 ° C. The amount of lignin in the residue was smaller when water was added, and it was found that the addition of water promoted the solubilization of lignin. This tendency was even more pronounced with hemicellulose, where 16% (based on wood weight) of hemicellulose remained after 30 minutes of treatment without water, whereas it was completely solubilized with water. On the other hand, it was found that solubilization of cellulose did not proceed in any case, and that cellulose did not decompose at this treatment temperature. This is thought to be due to the crystallinity of cellulose. As a result, when 10% by volume of water was added under the condition of 270 ° C, an insoluble residue in which almost only the cellulose component remained was recovered. This is considered to be effective as a method for isolating cellulose (pulping wood).

In addition, Fig. 4 shows the correlation between the treatment time and the amount of residue when 10% by volume of water was added and when water was not added when the treatment temperature was 350 ° C. At this temperature, solubilization of cellulose proceeded in all cases, but it was found that the solubilization was significantly promoted especially when water was added. It is considered that this is because the hydrogen bonds between the cellulose molecules are dissociated and the crystal structure is loosened under the temperature condition of 270 ° C or higher. As a result, as in the case of lignin and hemicellulose, it is considered that solubilization of cellulose was promoted by the acid catalytic effect of water. From these facts, it was confirmed that the addition of water promoted the decomposition and solubilization of all of the main constituents of wood, cellulose, hemicellulose and lignin, and the addition of an appropriate amount of water resulted in the desired chemical product. It was found that the optimum solubilization conditions for wood can be set in relation to.

<tables num="2"><img file="JP2005296906A_D0002.tif" /></tables>

In the above-described embodiment, the case of batch processing is shown, but the type of the apparatus for carrying out the manufacturing method of the present invention is not limited to this, and a continuous tank reactor, a piston flow reactor, and a tower reactor are used. A reactor similar to the one used for the reaction using supercritical water or the like can be used.

Table 3 shows the results of analysis of the decomposition products derived from cellulose in the water / methanol soluble part obtained by treating beech wood flour as biomass by the high performance liquid chromatography (HPLC). From this result, it was confirmed that the treatment time can be shortened and the obtained chemical product can be controlled by adding water.

<tables num="3"><img file="JP2005296906A_D0003.tif" /></tables>

In the biomass treatment proposed in the present invention for treating under supercritical or subcritical conditions of alcohol using a mixed solvent obtained by adding water to alcohol, the treatment conditions are obtained from the biomass to be treated and from the biomass. It is useful in the design of commercial systems because the reaction conditions of the supercritical or subcritical solvent can be easily controlled in relation to the chemical product.

<figref num="1">Correlation between the water content and the residual amount (% by weight) when beech wood, which is an example of biomass, is treated with a supercritical or subcritical water / methanol mixed solvent, which is one aspect of the present invention. Shown.</figref><figref num="2">The correlation between the treatment time and the residual amount (% by weight) when beech wood, which is an example of biomass, is treated using a water / methanol mixed solvent to which 10% by volume of water is added is shown. indicates the case where 10% by volume of water was added, and indicates the case where water was not added.</figref><figref num="3">The correlation between the treatment time and the residual amount (% by weight) when the beech wood is treated with a water / methanol mixed solvent at a temperature of 270 ° C and a treatment pressure of 30 MPa in Example 1 is shown.</figref><figref num="4">The correlation between the treatment time and the residual amount (% by weight) when the beech wood is treated with a water / methanol mixed solvent at a temperature of 350 ° C. and a treatment pressure of 50 MPa in Example 1 is shown.</figref>