Comparison of the decomposition behaviors of hardwood and softwood in supercritical methanol

The chemical conversion of Japanese beech (Fagus crenata Blume) and Japanese cedar (Cryptomeria japonica D. Don) woods in supercritical methanol was studied using the supercritical fluid biomass conversion system with a batch-type reaction vessel. Under conditions of 270°C/27 MPa, beech wood was decomposed and liquefied to a greater extent than cedar wood, and the difference observed was thought to originate mainly from differences in the intrinsic properties of the lignin structures of hardwood and softwood. However, such a difference was not observed at 350°C/43 MPa, and more than 90% of both beech and cedar woods were effectively decomposed and liquefied after 30 min of treatment. This result indicates that the supercritical methanol treatment is expected to be an efficient tool for converting the woody biomass to lower-molecular-weight products, such as liquid fuels and useful chemicals

Effects of solvent on pyrolysis-assisted catalytic hydrogenolysis of softwood lignin for high-yield production of monomers and phenols, as studied using coniferyl alcohol as a major primary pyrolysis product

Pyrolysis-assisted catalytic hydrogenolysis over Pd/C in anisole (phenyl methyl ether) at relatively high temperatures (>300 °C) can convert softwood lignin into aromatic monomers in >60 mol% yield (based on lignin aromatic rings). In this process, lignin is pyrolytically degraded to soluble intermediates prior to catalytic conversion, therefore the pyrolysis stage plays an important role in determining the yield and monomer composition. In this study, pyrolysis-assisted hydrogenolysis of coniferyl alcohol, which is a major pyrolysis product, and milled wood lignin isolated from Japanese cedar was investigated in various solvents, including water, methanol, toluene, hexane, and anisole, to clarify the solvent effects. The effects of the solvent on undesired side reactions were also explored. The results show that anisole is the best solvent for aromatic monomer production, but hexane is the best solvent for phenol production via demethoxylation. These findings provide insights that will facilitate the development of efficient methods for monomer production from lignin

Location of uronic acid group in Japanese cedar and Japanese beech wood cell walls as evaluated by the influences of minerals on thermal reactivity

The thermal reactivities of cellulose and hemicellulose are significantly different in cell walls when compared with isolated components and differ in Japanese cedar (softwood) and Japanese beech (hardwood). Uronic acid bound to xylan promotes the thermal degradation of cellulose and hemicellulose, and its effect is different depending on the form of free acid (acting as an acid catalyst) or metal uronate (acting as a base catalyst). We evaluated the location of uronic acid in the cell wall by identifying the components affected by demineralization in pyrolysis of cedar and beech wood. The thermal reactivities of xylan and glucomannan in beech were changed by demineralization, but in cedar, glucomannan and cellulose reactivities were changed. Therefore, the location of uronic acid in the cell wall was established and differed between cedar and beech; close to glucomannan and xylan in beech, but close to glucomannan and cellulose in cedar. Such information is important for understanding the ultrastructure and pyrolysis behavior of softwood and hardwood cell walls

Characterization of lignin-derived products from various lignocellulosics as treated by semi-flow hot-compressed water

To elucidate the decomposition behaviors of lignin from different taxonomic groups, five different lignocellulosics were treated with hot-compressed water (230 °C/10 MPa/15 min) to fractionate lignins into water-soluble portions, precipitates, and insoluble residues. The lignin-derived products in each fraction were characterized and compared. The delignification of monocotyledons [nipa palm (Nypa fruticans) frond, rice (Oryza sativa) straw, and corn (Zea mays) cob] was more extensive than that achieved for Japanese cedar (Cryptomeria japonica, gymnosperm) and Japanese beech (Fagus crenata, dicotyledon angiosperm). The water-soluble portions contained lignin monomers like coniferyl alcohol and phenolic acids, while the precipitates contained higher molecular weight lignin with high content of ether-type linkages. Lignin in the insoluble residues was rich in condensed-type structures. In all five lignocellulosics, ether-type linkages were preferentially cleaved, while condensed-type lignin showed resistance to hot-compressed water. In the monocotyledons, lignin–carbohydrate complexes were cleaved and gave lignins that had higher molecular weights than those eluted from the woods. These differences would facilitate the delignification in monocotyledons. Such information provides useful information for efficient utilization of various lignocellulosics

Characterization of three tissue fractions in corn (Zea mays) cob

Corn (Zea mays) cob is composed of three tissue fractions, chaff, woody ring, and pith, with dry weight percentages of 21.1%, 77.5%, and 1.4%, respectively. In this study, the cell wall components in these tissue fractions were characterized to examine their tissue morphology. The chemical compositions in the three fractions were relatively similar, and hemicellulose was the main component. Through sugar composition analysis, hemicellulose was mainly composed of xylan in all fractions, whereas the proportion of arabinose and galactose was different in the woody ring. From the alkaline nitrobenzene oxidation analysis, lignin in all fractions was composed of guaiacyl, syringyl, and p-hydroxyphenyl lignins, whereas their ratios varied in the three fractions. Furthermore, the amounts of cinnamic acids such as ferulic and p-coumaric acids, which are associated with corn lignin, were also different among the three fractions. With respect to the tissue morphology, the component cells in the three fractions were totally different each other. Furthermore, from the ultraviolet microspectrophotometry of each morphological region in the three tissue fractions, lignin concentration and distribution of cinnamic acids were different from one morphological region to another. The differences in chemical composition and lignin structures influence the decomposition behaviors in various treatments; thus, this information provides a clue to promote efficient utilization of corn cob into value-added chemicals

Influence of Proteins on the Lignin Decomposition Behavior of Japanese Cedar (Cryptomeria japonica) Wood by Supercritical Methanol Treatment

The effect of adding protein on the decomposition behavior of lignin in Japanese cedar under supercritical methanol conditions (270 °C/27 MPa) was studied. The Klason method was used to detect the lignin content in the insoluble residue following to a 30 min treatment. Adding either an animal (bovine serum albumin) or plant (soy) protein enhanced delignification from 50 to 65% of the lignin-based wt %. This result was attributed to enhanced lignin depolymerization owing to inhibited lignin recondensation and/or the suppressed formation of polysaccharide-derived char via reactions between the protein and polysaccharides. Although the solubilization of lignin was promoted and the yield of lignin-derived low-molecular-weight compounds increased, the selectivity of major monomers such as coniferyl alcohol (CA) and γ-methylated CA decreased. The addition of proteins has a substantial impact on the decomposition behavior of cell wall components under supercritical methanol conditions. This information provides insights into the use of protein-rich lignocelluloses

TiO2-supported Ni-Sn as an effective hydrogenation catalyst for aqueous acetic acid to ethanol

Various Ni and Ni-Sn catalysts supported on TiO2 were prepared and the catalytic activities were evaluated for ethanol formation from aqueous acetic acid. Although catalytic activities of the Ni/TiO2 catalysts were limited, the addition of Sn improved the activity dramatically, and the optimum Ni/Sn ratio was approximately 1:1 (w/w). SnO2, the precursor of Sn, could not be reduced into metal Sn in pure form but did reduce into Ni-Sn alloys in the presence of NiO, the precursor of Ni. Analyses with XRD and SEM-EDS revealed that the Ni-Sn alloys were homogeneously dispersed on the TiO2 surface. Furthermore, IR analysis indicated that the Ti atoms in the catalyst act as a Lewis acid, which coordinates to the oxygen atoms of acetic acid, enhancing the attack of hydrogens activated on neighboring Ni-Sn alloys. Based on these results, Ni-Sn/TiO2 is proposed as an effective hydrogenation catalyst for converting aqueous acetic acid into ethanol

Differential scanning calorimetric study of solidification behavior of monoacylglycerols to investigate the cold-flow properties of biodiesel

Monoacylglycerols (MAG) are impurities present in biodiesel as a result of incomplete reactions. MAG often solidify in biodiesel even at room temperature because of their high melting points. This worsens the cold‐flow properties such as the cloud point and pour point. We hypothesized that several types of MAG solidify simultaneously; therefore, we performed differential scanning calorimetry of binary mixtures of MAG to elucidate their interactions during solidification. Three thermodynamic formulas were then applied to the experimental results: (1) non‐solid‐solution, (2) solid‐solution, and (3) compound formation models. Binary mixtures of MAG showed complicated liquidus curves with multiple upward convex shapes, with which only the compound formation model fitted well. This model was applied to multicomponent mixtures that consisted of MAG and fatty acid methyl esters (FAME) as surrogate biodiesel fuels. We confirmed that the model still worked well. The results show that the compound formation model has good potential for predicting the cold‐flow properties of biodiesel

Treatment of mandibular condyalr osteochondroma

We successfully treated a case of facial asymmetry involved in unilateral mandibular condylar osteochondroma with ipsilateral mandibular condylectomy and contralateral ramus osteotomy. A female, 32-year 11-month of age, had a chief complaint of facial asymmetry which initiated about 10 years ago. A mirror image analysis using a non-contact 3D image scanner revealed that the soft tissue on the deviated side was protruded more than 5.50 mm compared with the non-deviated side. The patinet was diagnosed as facial asymmetry with a skeletal Class III jaw-base relationship caused by unilateral mandibular condylar osteochondroma. After 18 months of preoperative orthodontic treatment, ipsilateral condylectomy and contralateral sagittal split ramus osteotomy were performed. As the results of postoperative orthodontic treatment for 20 months, an ideal occlusion having a Class I molar relationship with an adequate interincisal relationship was achieved. Facial asymmetry and mandibular protrusion were dramatically improved, and the differences between the deviation and non-deviation sides were decreased to less than 1.11 mm. The acceptable occlusion and symmetric face were maintained throughout 1-year retention period. Conclusively, our results indicated the stability after condylectomy without condylar reconstruction in a patient with unilateral condylar osteochondroma

Predicting Solid–Liquid Equilibrium of Fatty Acid Methyl Ester and Monoglyceride Mixtures as Biodiesel Model Fuels

An erratum to this article is available at https://doi.org/10.1007/s11746‐017‐3029‐4.Fatty acid methyl esters from plant oils are the main component of biodiesel and used as a substitute for petroleum diesel. Biodiesel generally contains a small amount of monoglycerides as intermediate compounds, which have high melting points and often solidify and clog fuel filters. The prediction of the cold‐flow property of biodiesel is of great importance for practical application. In this study, a thermodynamic study was conducted for mixtures of monoglycerides and fatty acid methyl esters. Temperatures of the solid–liquid equilibrium for the mixtures were measured by differential scanning calorimetry and visual observation, while the theoretical values were calculated using the modified Universal Quasi‐chemical Functional‐group Activity Coefficients (UNIFAC) model (Dortmund). The theoretical and experimental results were in good agreement, especially for binary mixtures of monoglycerides and methyl esters. The importance of monoglycerides on the cold‐flow properties of biodiesel was determined, and the effects could be well described by the modified UNIFAC model (Dortmund)