Masao Shibata

Reaction model of cellulose decomposition in near-critical water and fermentation of products

Abstract The properties of the products obtained in the cellulose decomposition process conducted in near-critical water were analyzed using HPLC, GPC and IR. The properties of the products changed with the progress of the reaction and a reaction model consisting of the formation process of water solubles (WS) and the subsequent second decomposition process was proposed. The WS formation process is a saccharification process where hydrolysis preferentially progresses. The second decomposition process is a carbonization process of WS, where the elimination of functional groups leads to the formation of gaseous products and insolubilization of WS. The hydrolyzate solution obtained in the sacharification process could be used as a feedstock of ethanol fermentation and the fermentation rate of the solution was improved by removing furfurals with an active carbon treatment.

Lanthanum(III)-catalyzed degradation of cellulose at 250 °C

Abstract Lanthanum(III) chloride was found to effectively catalyze the degradation of cellulose in water at 250 °C. The degradation conversion of cellulose in the presence of a catalytic amount of lanthanum chloride reached 80.3% after 180 s, which corresponded to the turnover number of 83, whereas the reaction did scarcely proceed in the absence of the catalyst. The degradation products were separately quantified as water-soluble (WS), methanol-soluble (MS), methanol-insoluble (MI), and gaseous (G) products. The HPLC and GC analyses revealed that the WS materials are mainly composed of 5-hydroxymethyl-2-furaldehyde (HMF), d -glucose, and levulinic acid. Cellobiose, the disaccharide component of cellulose, was scarcely detected during the reaction.

Supercritical fluid extraction of coal under pyrolysis conditions

Abstract Supercritical fluid extraction of Wandoan coal was carried out under pyrolysis conditions using hexane, benzene, toluene and a toluene-tetralin mixture. The residues and extracts obtained were analysed using solid state 13 C nuclear magnetic resonance (n.m.r.) spectroscopy, gas chromatography (g.c.), gas chromatography-mass spectrometry (g.c.-m.s.) and gel permeation chromatography (g.p.c.), respectively, to clarify the relation among the extraction yield, the solvent power of the supercritical fluid, and the reactions taking place during extraction. The decrease in conversion, defined by 100—residue yield, at higher extraction temperatures above 653 K, was mainly due to the aromatization of coal. The aromatization was suppressed by addition of tetralin to the extraction solvent, which resulted in an increase in conversion. The extract yield was increased, without increasing the gas yield, through the enhancement of solvent power by increasing the extraction pressure or selecting the solvent. The extraction solvents used were found to be partly condensed to dimers during the extraction. The condensation of toluene was inhibited by addition of tetralin, but another dimer between tetralin and toluene was formed instead. Conversion was increased and dimer formation suppressed by impregnating tetralin into the coal in advance.

Application of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry to insoluble glucose oligomers in decomposed cellulose.

An analytical approach is described for the molecular weight characterization of glucose oligomers from cellulose which had been decomposed by hot-compressed water (HCW). Microcrystalline cellulose was decomposed to 18% of water insoluble fraction (WI) plus 82% of water soluble fraction (WS) by HCW (295 degrees C, 10 mL/min). The glucose oligomers in the WI were analyzed by pericullar anion exchange chromatography, and oligomers longer than pentamers were detected. These results were also confirmed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS). Many peaks derived from glucose oligomers with molecular weights less than 4000 Da were detected in the spectra. Mass differences between peaks were 162 Da, as expected for polymers composed of glucose units. This appears to be the first report concerning molecular weight determination of water or organic solvent insoluble compounds like glucose oligomers from cellulose using MALDI-TOFMS.

Chromatographic separation of metal ions on a macroreticular cation-exchange resin with hydrochloric acid N aqueous acetone solution

Abstract Forced-flow chromatography on a cation-exchange resin has been used to obtain rapid separations of metal ions, such as Cd(II), Zn(II), Fe(III), Pb(II), Cu(II), Co(II) and Mn(II). The macroreticular resin used provides rapid separations in hydrochloric acid-acetone media covering acid and acetone concentration ranges of 0.1–1.88 M and 70–96%, respectively. On-stream addition of a colour-forming reagent provides continuous detection and quantitation of the eluted metals.

Deashing characteristics in solvolysis coal liquefaction process

Abstract Deashing of solvolysis pitch (SP) of Miike coal was studied using settling, filtration and centrifugation. The SP obtained by the reaction below 673 K was smoothly filtered at temperatures above 623 K. Filtration was also possible at 338 K when the SP was diluted with quinoline and mixed with a small amount of fine coke powder. However, the SP obtained by the reaction above 683 K was quite different from that prepared below 673 K and was difficult to filter at elevated temperatures. It could be filtered at 338 K after dilution with quinoline. For all the samples, filtration was superior to settling and centrifugation. The optimum deashing system was proposed for each SP.

The Pulverizing Behavior of Coals in Organic Solvents

The pulverizing behavior of coals in organic solvents has been studied by a homogenizer-type pulverizer. The pulverized coal powder exhibited a particle size distribution consisting of coarse and fine particles divided at around 70μm. Illinois No. 6 coal was pulverized easily in solvents such as toluene and hexane which hardly swelled the coal, but it was not easy to pulverize in solvents such as acetone and ethanol which swelled the coal. The pulverizing characteristics also depended on the coal rank. The low rank coals, Wandoan and Wabamun, were hard to pulverize in toluene. Vitrinites and inertinites were condensed in the fine and coarse particles, respectively.

Initial Stage Liquefaction of Coal in the Process of Rising Temperature. (II). Effects of Coal Ranks.

The initial stage liquefaction of six coals, Estevan, Wabamun, Taiheiyo, Wandoan, Illinois No.6 and Lingan coals, was studied. Heat-treatment of coal and a hydrogenated anthracene oil slurry (1: 3 by weight) was carried out using a pipe reactor which was designed to recover six heat-treated samples at progressively higher temperatures. About 3.4min. were required to raise the temperature from room temperature to around 450°C.Pyridine insolubles, PI, decreased with an increase in temperature in all coals studied. In the cases of Taiheiyo and Illinois No.6 coals, PI values of the sixth samples (445°C) were less than 10%, showing that the initial stage liquefaction reaction of both coals was almost completed. The sixth samples of Wandoan and Lingan coals had small PI values of less than 16%. Estevan and Wabamun coals had PI values of around 45% in the sixth samples.In the cases of Taiheiyo, Wandoan, Illinois No.6 and Lingan coals, the change of viscosity of each slurry with temperature showed a maximum. This maximum is caused by the swelling and disintegration of coal particles with increasing temperature. Estevan and Wabamun coals, which did not have small PI values in the sixth samples, did not show such a maximum.The viscosity and weight-average molecular weight of filtrate increased as the reaction progressed.Hydrogen released from hydrogen donor components in the hydrogenated anthracene oil played an important role in the initial stage of coal liquefaction. Judging from the relation between PI value and the amount of released hydrogen, the coal conversion per unit amount of released hydrogen was found to largely depend on coal rank.

SOLID-STATE C13-NMR STUDIES ON THE INITIAL STAGE OF COAL LIQUEFACTION

Publisher Summary This chapter presents a solid-state C13-NMR study on the initial stage of coal liquefaction. Illinois #6 coal was used in this study. The coal was ground to under 200 mesh and was dried just before use. Hydrogenated anthracene oil (HAO) was used as a solvent. HAO was prepared by hydrogenation of anthracene oil with Ni–Mo catalyst at 15 MPa of hydrogen at 380°C for 2 h. The preheating reactor was constructed by six stainless steel pipes of 3 m length connected in a series. The temperature of each pipe was controlled by an individual heater. Six sampling vessels were connected to each pipe through sampling valves. The pipe reactor and sampling vessels were kept at a certain pressure by a regulating valve. In the conventional CP/MAS spectra, several spinning side-bands appeared, and one of them overlapped completely with the aliphatic bands in the spectrum obtained with 4 kHz spinning.