JPH0216101A - Hydrolysis of hemicellulose with solid acid - Google Patents

Abstract

PURPOSE:To make it possible to obtain monosaccharides at low cost by hydrolyzing hemicelluloses in waste liquor of the extract from woods using a solid acid, thereby facilitating the recovery of the solid acid from the waste liquor after the hydrolysis and making it possible to reuse the solid acid. CONSTITUTION:Water-soluble hemicelluloses in waste liquor of the extract from woods which are obtained in pulping or fibrillation of woods without using inorganic chemicals are hydrolyzed using a solid acid, preferably a strongly acidic cation exchange resin (e.g. polystyrenesulfonic acid). For example, the above hemicelluloses are heated at 100-150 deg.C while being brought into contact with a cation exchange resin, thereby hydrolyzing the hemicelluloses to produce monosaccharides. According to the above process, hydrolysis can be carried out continuously by using a column without decomposition of the solid acid and the recovery of the solid acid from the waste liquor after the hydrolysis can be carried easily.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for obtaining @sugar by hydrolyzing water-soluble hemicellulose contained in a waste liquid containing few W double salts with a solid acid.

More specifically, the present invention relates to a method for economically converting water-soluble hemicellulose contained in wood component extraction waste liquid produced during wood fibrillation or organosolv pulpization into monosaccharides using a solid acid.

The present invention is applied to pulping waste liquid or wood component extraction waste liquid that is low in inorganic salts, and is utilized as a new method for producing monosaccharides.

[Prior Art] Currently used methods for hydrolyzing cellulose and hemicellulose mainly use mineral acids or enzymes. When using mineral acids, neutralization treatment is required, and it is difficult to economically recover only monosaccharides.・Additionally, when enzymes are used, there are problems with the cost of the enzymes and the inactivation of the enzymes due to trace components in the waste liquids, which poses problems when applied to waste liquids. In addition, fluororesin-based solid strong acids have been developed in recent years, and their application to hydrolysis of carbohydrates has been considered, but the cost of solid strong acids is extremely high and they cannot be used for waste liquids.

[Problems to be solved by the invention] In conventional pulping or wood defibration methods, it is common for large amounts of inorganic salts to be mixed into the extraction waste liquid, or for sugar components to already be present in the form of monosaccharides. there were. However, new pulping and defibration methods are being considered that do not use physical methods or inorganic chemicals. There are few inorganic salts in the wastewater, and a high concentration of hemicellulose is accumulated.

The present invention hydrolyzes hemicellulose in such wood extraction waste liquid using a solid acid, thereby facilitating recovery of the solid acid from the waste liquid after hydrolysis. The aim is to simplify the hydrolysis process and reduce costs.

[Means for Solving the Problems] The present inventors conducted research on a method for hydrolyzing hemicellulose in waste liquid obtained by pulping method using an organic solvent (solvolysis pulping method). We have discovered a method for producing monosaccharides using a cation exchange resin as a solid acid catalyst for hydrolysis, and have completed the present invention.

The solvolysis pulping method is a new pulping method that uses an aqueous cresol solution as a cooking solvent for wood pulping, and the cresol is recovered and reused after cooking. Therefore, the waste liquid contains few inorganic ions and a high concentration of hemicellulose. This hemicellulose is mainly composed of xylan when the wood is hardwood, and mannan when the wood is softwood.
To produce xylose and mannose from these, it is necessary to hydrolyze hemicellulose.

The present invention is characterized in that in hydrolyzing hemicellulose contained in such wastewater to obtain monosaccharides, a strongly acidic cation exchange resin such as polystyrene sulfonic acid is used as the solid acid. These resins have a large ion exchange capacity, that is, catalytic ability, and are easily available as they are commercially available for water treatment.

By filling this resin into a pressure-resistant column and passing the waste solution containing hemicellulose through it without heating, the microcellulose is easily hydrolyzed into monosaccharides, and the waste solution containing monosaccharides can be obtained as an effluent. I can do it.

In addition to passing the solution through a column as described in E, hydrolysis can also be carried out in batches by heating in an autoclave.

[Operations and Examples] Next, the method of carrying out the present invention will be explained using experimental results as examples.

Example 1 100 solvolysis pulping waste liquid in autoclave
5 g of strongly acidic cation-exchanged plum fat of the polystyrene sulfonic acid type was added to each ml, and the mixture was heated at various temperatures while stirring, and the concentration of xylose produced was examined.

As shown in No. 1m, when the heating temperature is kept at 150°C, which is the usual heat-resistant temperature of this resin, the hemicellulose hydrolysis efficiency is highest when the contact time is 40 minutes, and at higher temperatures, the amount of xylose produced is In fact, it has declined. At this maximum value, xylose production reached approximately 90% of that for the mineral acid catalyst. Since it is necessary to take a long contact time when the temperature is low, when using this resin, 40 minutes at 150° C. is preferable.

Example 2 A stainless steel column with an inner diameter of 15 mm and a length of 30 cm was filled with resin, and the waste liquid from softwood chip defibration was poured into the column heated in an oil bath at a flow rate of 1 to 10 ml/mi.
The mannose concentration in the eluate was determined.

As shown in FIG. 2, the mannose concentration at 150° C. reached its maximum at a flow rate of 3 ml/min.

The filled resin will adsorb trace amounts of inorganic salts (cations such as potassium, calcium, magnesium, etc.) in the waste liquid, and the catalytic ability will gradually decrease, or the catalytic ability will gradually decrease, or it will be removed at regular intervals by dilute aqueous solution of sulfuric acid or hydrochloric acid. I was able to recover it by regenerating it.

Contamination of the resin with organic substances also occurred during long-term use, but by washing the resin with an approximately 5N sodium hydroxide solution, approximately 80% recovery was possible.

[Effects of the Invention] When the hemicellulose in the wood extraction waste liquid is hydrolyzed by the method of the present invention, the hydrolysis can be carried out economically due to the separation of the solid acid that is the catalyst.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between the contact time to the resin and the production of xylose when the present invention is carried out by a batch method and heated at 150°C. The resin was added in an amount of 5% to the solvonosis pulping waste liquid. FIG. 2 shows the case where the column method according to the present invention is used. It is a graph showing the relationship between the liquid passage rate and the mannose production concentration when waste liquid generated from fibrillation of softwood material is passed through a resin-filled column (15 mm x 30 cm) heated to 150°C. Patent Applicant Kozo Iizuka, Director of the Agency of Industrial Science and Technology, Designated Representative of the Agency of Industrial Science and Technology, Shikoku Industrial Technology'J, Director of the Institute, Kazuhiko Sugayoshi, Figure 1, Resin Hi no Mine, J Kujikuni (5) Renshokan II (To G7, 1 Ru )

Claims (2)

[Claims] (1) A method of hydrolyzing water-soluble hemicellulose produced during pulping or fibrillation of wood using a solid acid without using inorganic chemicals. (2) Using a cation exchange resin as a solid acid, the water-soluble hemicellulose is hydrolyzed by heating between 100 and 150°C while contacting with the water-soluble hemicellulose described in claim 1, and the monosaccharide How to get.