Preparation and analysis of carbonization products from Sugi (Cryptomeria japonica D. Don) wood

The material balance of carbonization products (wood-gas, wood-vinegar, wood-tar and charcoal) prepared from the sapwood and the heartwood of Sugi (Cryptomerica japonica D. Don) at various temperatures was determined. The evolution of both carbon monoxide and carbon dioxide mainly occurred at the carbonization temperature below 600 degrees C and that of hydrogen and methane at 600-800 degrees C. Total yield of the wood-vinegar and the wood-tar was almost constant at 500-800 degrees C. On the other hand, the yield of the charcoal decreased because of the evolution of the wood gas with an increase in carbonization temperature. The wood-vinegars prepared at the temperature over 400 degrees C were found to consist of carboxylic acids such as acetic acid and propionic acid, methanol, acetone, furans, alkylphenols, guaiacols, cyclotene and maltol by capillary gas chromatography. Since the constituent varieties and contents of the wood-vinegars prepared at both 400 degrees C and 800 degrees C were very similar each other, the wood-vinegar of Sugi wood chiefly produced below 400 degrees C. FT-IR spectra of the charcoals showed the generation of carbonyl and olefin groups at 300-400 degrees C and then the formation of aromatic rings along with the disappearance of carbonyl groups over 600 degrees C. The production of radical species in the charcoals carbonized at 300-600 degrees C was observed by ESR, on the contrary, the charcoals carbonized over 700 degrees C were inactive. The specific surface area and the pore volume of the charcoal of Sugi sapwood increased with an increase in carbonization temperature. The pH of charcoal-dispersed aqueous solution increased with an increase in carbonization temperature. The high adsorptive activity of the charcoal carbonized at 400 degrees C for ammonia gas and that at 800 degrees C for hydrogen sulfide gas seemed to be dependent on acidic and basic properties of the charcoals, respectively.