scholarly journals Effect of acetic acid addition on chemical conversion of woods as treated by semi-flow hot-compressed water

Holzforschung ◽  
2011 ◽  
Vol 65 (5) ◽  
Author(s):  
Natthanon Phaiboonsilpa ◽  
Shiro Saka
Keyword(s):  
Acetic Acid ◽  
Flow Reactor ◽  
Japanese Cedar ◽  
Chemical Conversion ◽  
Fagus Crenata ◽  
Japanese Beech ◽  
Appropriate Treatment ◽  
One Step ◽  
Decomposition Behavior ◽  
Hot Compressed Water

Abstract Effect of acetic acid (AcOH) addition on chemical conversion of Japanese beech (Fagus crenata), as a hardwood, and Japanese cedar (Cryptomeria japonica), as a softwood, was investigated in the course of treatment in a semi-flow reactor with hot-compressed water (H-CW). One-step treatment of Japanese beech was preliminarily performed to examine the effect of AcOH concentrations on the decomposition behavior at 150–290°C/10 MPa/30 min. Based on the obtained results, two-step semi-flow H-CW treatment with 1 wt% AcOH at 210°C/10 MPa/15 min (1st stage) and 260°C/10 MPa/15 min (2nd stage) was thus selected as the most appropriate treatment and a comparative study of the two woods was accordingly conducted. The differences in decomposition behavior observed between the two woods clearly proved that the addition of AcOH played an important role in enhancing the hydrolysis and decomposition of cell wall components in Japanese cedar due to the lesser amount of acetyl residue in softwood hemicelluloses and its lignin structure.

scholarly journals Visualization and Localization of Submicron-Sized Ammonium Sulfate Particles on Needles of Japanese Larch (Larix kaempferi) and Japanese Cedar (Cryptomeria japonica) and Leaves of Japanese Beech (Fagus crenata) and Japanese Chinquapin (Castanopsis sieboldii) after Artificial Exposure

Forests ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 1151
Author(s):  
Kenichi Yamane ◽  
Satoshi Nakaba ◽  
Masahiro Yamaguchi ◽  
Katsushi Kuroda ◽  
Yuzou Sano ◽  
...  
Keyword(s):  
Ammonium Sulfate ◽  
Cryptomeria Japonica ◽  
Japanese Cedar ◽  
Fagus Crenata ◽  
Japanese Larch ◽  
Larix Kaempferi ◽  
Abaxial Side ◽  
Japanese Beech ◽  
Aerosol Generator ◽  
Castanopsis Sieboldii

We applied a method combining field-emission scanning electron microscopy (FE-SEM) with energy dispersive X-ray spectrometry (EDX) to visualize the deposition and localization of the submicron-sized ammonium sulfate (AS) particles. The AS particles emitted from an aerosol generator in the laboratory were spherical in shape and individually deposited without aggregation on the surface of a silicon substrate. We determined the AS particles on the surfaces of the needles of Japanese larch (Larix kaempferi) and Japanese cedar (Cryptomeria japonica), and the leaves of Japanese beech (Fagus crenata) and Japanese chinquapin (Castanopsis sieboldii), using EDX. The particles were deposited on either the adaxial or abaxial side of the leaves and needles. The AS particles deposited on the surfaces of the leaves and needles did not aggregate, and they were deposited on the surfaces of the leaves and needles in the same manner, regardless of leaf structure. These results, using a new method, highlight the early stages of the deposition and localization of submicron-sized AS particles on the surfaces of the leaves and needles of forest trees.

Characterization of the precipitated lignin from Japanese beech as treated by semi-flow hot-compressed water

Holzforschung ◽  
2017 ◽  
Vol 71 (4) ◽  
pp. 285-290 ◽  
Author(s):  
Masatsugu Takada ◽  
Eiji Minami ◽  
Kazuchika Yamauchi ◽  
Haruo Kawamoto ◽  
Shiro Saka
Keyword(s):  
Secondary Wall ◽  
Fagus Crenata ◽  
Spectroscopic Methods ◽  
Ambient Conditions ◽  
Flow Process ◽  
Japanese Beech ◽  
Milled Wood Lignin ◽  
Nitrobenzene Oxidation ◽  
Hot Compressed Water

Abstract Japanese beech (Fagus crenata) was decomposed by a semi-flow process in hot-compressed water (HCW) at 150~230°C/10 MPa for 25 min. Mainly hemicelluloses and partly the lignin moiety of the wood was affected and liquefied in water. A part of the liquefied products can be precipitated after 12 h standing at ambient conditions. The precipitates are composed of around 90% of lignin, which was quantified and characterized by various chemical and spectroscopic methods in comparison of milled wood lignin (MWL), which is considered to be a representative compound for the native lignin in wood. The yield of the precipitated lignin (Lprecip) is higher than that of MWL and its syringyl content is also higher as demonstrated by alkaline nitrobenzene oxidation (NBO) giving rise to higher syringaldehyde/vanillin (SA/VA) ratios. Its OHphen group content was also high. The interpretation is that Lprecip is mainly from the secondary wall, and accordingly, the presented semi-flow HCW treatment offers the possibility for an efficient lignin isolation.

scholarly journals Effect of delignification on thermal degradation reactivities of hemicellulose and cellulose in wood cell walls

2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Jiawei Wang ◽  
Eiji Minami ◽  
Mohd Asmadi ◽  
Haruo Kawamoto
Keyword(s):  
Thermal Degradation ◽  
Cell Walls ◽  
Japanese Cedar ◽  
Fagus Crenata ◽  
Cellulose Microfibrils ◽  
Japanese Beech ◽  
Base Catalysts ◽  
Research Fields ◽  
Acid And Base ◽  
The Matrix

AbstractThe thermal degradation reactivities of cellulose and hemicellulose are substantially different in Japanese cedar (Cryptomeria japonica, a softwood) and Japanese beech (Fagus crenata, a hardwood). Uronic acid and its salts act as acid and base catalysts, respectively, and their specific placement in the cell walls has been considered a factor that influences degradation reactivity. In this study, the role of lignin in degradation reactivity was investigated using holocellulose prepared from cedar and beech woods. The thermal degradation reactivities of cellulose and hemicellulose in holocellulose were evaluated according to the recovery of hydrolyzable sugars from heat-treated samples and compared with those of wood samples. Results show that the reactivities of xylan and glucomannan in both woods became similar to those of the corresponding isolated samples when lignin was removed. By contrast, the cellulose in both woods became more reactive when lignin was removed, and the degradation could be separated into two modes depending on the reactivity. These results were analyzed in terms of the effect of lignin on the matrix of cell walls and the interaction between the matrix and surface molecules of cellulose microfibrils. Differential thermogravimetric curves of the holocellulose samples were obtained and explained in terms of the degradation of hemicellulose and cellulose. The reported findings will provide insights into the research fields of wood pyrolysis and cell wall ultrastructures.

Droplet Factories: Synthesis and Assembly of Silver and Palladium Nanoparticles at the Liquid-Liquid Interface

2019 ◽  
Author(s):  
Suchanuch Sachdev ◽  
Rhushabh Maugi ◽  
Sam Davis ◽  
Scott Doak ◽  
Zhaoxia Zhou ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Reaction Rate ◽  
Tertiary Structure ◽  
Flow Reactor ◽  
Pd Nanoparticles ◽  
Subsequent Removal ◽  
Immiscible Liquids ◽  
Flow Reactors ◽  
Droplet Flow ◽  
One Step

<div>The interface between two immiscible liquids represent an ideal substrate for the assembly of nanomaterials. The defect free surface provides a reproducible support for creating densely packed ordered materials. Here a droplet flow reactor is presented for the synthesis and/ or assembly of nanomaterials at the interface of the emulsion. Each droplet acts as microreactor for a reaction between decamethylferrocene (DmFc) within the hexane and metal salts (Ag+/ Pd2+) in the aqueous phase. The hypothesis was that a spontaneous, interfacial reaction would lead to the assembly of nanomaterials creating a Pickering emulsion. The subsequent removal of the solvents showed how the Ag nanoparticles were trapped at the interface and retain the shape of the droplet, however the Pd nanoparticles were dispersed with no tertiary structure. To further exploit this, a one-step process where the particles are synthesised and then assembled into core-shell materials was proposed. The same reactions were performed in the presence of oleic acid stabilise Iron oxide nanoparticles dispersed within the hexane. It was shown that by changing the reaction rate and ratio between palladium and iron oxide a continuous coating of palladium onto iron oxide microspheres can be created. The same reaction with silver, was unsuccessful and resulted in the silver particles being shed into solution, or incorporated within the iron oxide micro particle. These insights offer a new method and chemistry within flow reactors for the creation of palladium and silver nanoparticles. We use the technique to create metal coated iron oxide nanomaterials but the methodology could be easily transferred to the assembly of other materials.</div><div><br></div>

scholarly journals Quinazolin-4(3H)-ones and 5,6-Dihydropyrimidin-4(3H)-ones from β-Aminoamides and Orthoesters

Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2925 ◽  
Author(s):  
Joshua Gavin ◽  
Joel Annor-Gyamfi ◽  
Richard Bunce
Keyword(s):  
Acetic Acid ◽  
Melting Point ◽  
1H Nmr ◽  
13C Nmr ◽  
Pressure Tube ◽  
Absolute Ethanol ◽  
Basic Nitrogen ◽  
One Step ◽  
Ft Ir

Quinazolin-4(3H)-ones have been prepared in one step from 2-aminobenzamides and orthoesters in the presence of acetic acid. Simple 2-aminobenzamides were easily converted to the heterocycles by refluxing in absolute ethanol with 1.5 equivalents of the orthoester and 2 equivalents of acetic acid for 12–24 h. Ring-substituted and hindered 2-aminobenzamides as well as cases incorporating an additional basic nitrogen required pressure tube conditions with 3 equivalents each of the orthoester and acetic acid in ethanol at 110 °C for 12–72 h. The reaction was tolerant towards functionality on the benzamide and a range of structures was accessible. Workup involved removal of the solvent under vacuum and either recrystallization from ethanol or trituration with ether-pentane. Several 5,6-dihydropyrimidin-4(3H)-ones were also prepared from 3-amino-2,2-dimethylpropionamide. All products were characterized by melting point, FT-IR, 1H-NMR, 13C-NMR, and HRMS.

scholarly journals Two-Step Decomposition Behavior of Rice Straw as Treated by Semi-Flow Hot-Compressed Water

2013 ◽  
Vol 92 (4) ◽  
pp. 319-326 ◽  
Author(s):  
Mai OGURA ◽  
Natthanon PHAIBOONSILPA ◽  
Kazuchika YAMAUCHI ◽  
Shiro SAKA
Keyword(s):  
Rice Straw ◽  
Decomposition Behavior ◽  
Hot Compressed Water
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