Studies on the products resulting from the conversion of aspen poplar to an oil

1981 ◽  
Vol 59 (14) ◽  
pp. 2191-2198 ◽  
Author(s):  
Richard L. Eager ◽  
Joseph F. Mathews ◽  
James M. Pepper ◽  
Hussein Zohdi
Keyword(s):  
Carbon Dioxide ◽  
Elevated Temperatures ◽  
Exothermic Reaction ◽  
Complex Mixture ◽  
Water Soluble ◽  
Low Molecular Weight ◽  
Oxygenated Water ◽  
Model Substances ◽  
Chemical Products ◽  
Increasing Temperature

Some observations are made on the nature of the reactions involved in the conversion of aspen poplar into a variety of chemical products as a result of its interaction with carbon monoxide and water in the presence of sodium carbonate at elevated temperatures and pressures. The original carbon content of the wood is distributed between an oil phase, a complex mixture of highly oxygenated water-soluble products many of which have been identified as low molecular weight aliphatic alcohols, ketones, and acids, and a gaseous phase consisting of mainly hydrogen and carbon dioxide. Using model substances (cellulose, cellobiose, D-glucose, D-fructose, D-xylose, D-sorbitol, glycerol, and an isolated lignin) information was obtained on the origin of the oil and of the water-soluble products. Studies at temperatures from 160° to 360 °C revealed a marked exothermic reaction occurring in the 200–240 °C range for wood and cellulose and which was reflected in the nature of the resulting product. With increasing temperature there is an increase in the yields of the water-soluble derivatives and also a change in their relative abundance.

scholarly journals The changes of Ba0.5Sr0.5Co0.8Fe0.2O3-δ perovskite oxide on heating in oxygen and carbon dioxide atmospheres

2014 ◽  
Vol 79 (9) ◽  
pp. 1141-1154 ◽  
Author(s):  
Sasa Zeljkovic ◽  
Toni Ivas ◽  
Sebastien Vaucher ◽  
Dijana Jelic ◽  
Ludwig Gauckler
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Elevated Temperatures ◽  
Oxygen Deficiency ◽  
Perovskite Oxide ◽  
X Ray ◽  
Equilibrium Reaction ◽  
Increasing Temperature

In the first part of this study, the oxygen deficiency, ?, in Ba0.5Sr0.5Co0.8Fe0.2O3 - ? (BSCF) was measured by means of thermogravimetry as a function of oxygen partial pressure, p(O2), in the range of 1.1?10?6 < p(O2)/% < 41.67 at elevated temperatures ranging 873 ? T/K ? 1073. It was shown that ? becomes more pronounced with increasing T and with decreasing p(O2). The isotherms ? vs. p(O2) were determined. The second part of this study relates to the reaction of CO2 with Ba0.5Sr0.5Co0.8Fe0.8O3-? perovskite oxide in the absence and presence of O2 at temperatures ranging from 673 to 973 K also by thermogravimetry. The reactivity of CO2 with BSCF increased with increasing temperature and increasing exposure to CO2. Reaction of CO2 with BSCF was described by a equilibrium reaction isotherms. The results of X-ray diffractometry evidenced that the exposure to CO2 leads to the formation of carbonates.

Molecular, rheological and physicochemical characterisation of puka gum, an arabinogalactan-protein extracted from the Meryta sinclairii tree

2020 ◽  
Author(s):  
MSM Wee ◽  
Ian Sims ◽  
KKT Goh ◽  
L Matia-Merino
Keyword(s):  
Hydrodynamic Radius ◽  
Average Molecular Weight ◽  
Gum Arabic ◽  
Water Soluble ◽  
Arabinogalactan Protein ◽  
Type Ii ◽  
Weight Average Molecular Weight ◽  
Soluble Polysaccharide ◽  
Physicochemical Characterisation ◽  
Increasing Temperature

© 2019 Elsevier Ltd A water-soluble polysaccharide (type II arabinogalactan-protein) extracted from the gum exudate of the native New Zealand puka tree (Meryta sinclairii), was characterised for its molecular, rheological and physicochemical properties. In 0.1 M NaCl, the weight average molecular weight (Mw) of puka gum is 5.9 × 106 Da with an RMS radius of 56 nm and z-average hydrodynamic radius of 79 nm. The intrinsic viscosity of the polysaccharide is 57 ml/g with a coil overlap concentration 15% w/w. Together, the shape factor, p, of 0.70 (exponent of RMS radius vs. hydrodynamic radius), Smidsrød-Haug's stiffness parameter B of 0.031 and Mark-Houwink exponent α of 0.375 indicate that the polysaccharide adopts a spherical conformation in solution, similar to gum arabic. The pKa is 1.8. The polysaccharide exhibits a Newtonian to shear-thinning behaviour from 0.2 to 25% w/w. Viscosity of the polysaccharide (1 s−1) decreases with decreasing concentration, increasing temperature, ionic strength, and at acidic pH.

ANALISA KANDUNGAN BETA-GLUKAN LARUT AIR DAN LARUT ALKALI DARI TUBUH BUAH JAMUR TIRAM (Pleurotus ostreatus) DAN SHIITAKE (Lentinus edodes)

2013 ◽  
Vol 13 (3) ◽  
Author(s):  
Netty Widyastuti ◽  
Teguh Baruji ◽  
Henky Isnawan ◽  
Priyo Wahyudi ◽  
Donowati Donowati
Keyword(s):  
Molecular Structure ◽  
Molecular Weight ◽  
Immune System ◽  
Pleurotus Ostreatus ◽  
Water Soluble ◽  
Low Molecular Weight ◽  
Lentinus Edodes ◽  
Beta Glucan ◽  
Oyster Mushrooms ◽  
The Difference

Beta glucan is a polysaccharide compound, generally not soluble inwater and resistant to acid. Beta glucan is used as an immunomodulator (enhancing the immune system) in mammals is usually a beta-glucan soluble in water, easily absorbed and has a low molecular weight. Several example of beta-glucan such as cellulose (β-1 ,4-glucan), lentinan (β-1 0.6-glucan) and (β-1 ,3-glucan), pleuran (β-1, 6 and β-1 ,3-glucan) are isolated from species of fungi Basidiomycota include mushrooms (Pleurotus ostreatus) and shiitake (Lentinus edodes).The purpose of thisresearch activity is to obtain beta-glucan compound that can be dissolved in water and in alkali derived from fungi Basidiomycota, i.e, Oyster mushrooms (Pleurotus ostreatus) and shiitake (Lentinus edodes). The result of beta-glucan compared to characterize the resulting beta glucan that is molecular structure . The difference of beta glucan extraction is based on the differences in solubility of beta-glucan. Beta glucan could be water soluble and insoluble water.

scholarly journals Investigation into the Re-Arrangement of Copper Foams Pre- and Post-CO2 Electrocatalysis

Chemistry ◽  
2021 ◽  
Vol 3 (3) ◽  
pp. 687-703
Author(s):  
Jennifer A. Rudd ◽  
Sandra Hernandez-Aldave ◽  
Ewa Kazimierska ◽  
Louise B. Hamdy ◽  
Odin J. E. Bain ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Carbon Dioxide ◽  
Carbon Capture ◽  
Surface Composition ◽  
Structural Rearrangement ◽  
Copper Electrode ◽  
Copper Electrodes ◽  
Porous Copper ◽  
Chemical Products ◽  
Co2 Electrolysis

The utilization of carbon dioxide is a major incentive for the growing field of carbon capture. Carbon dioxide could be an abundant building block to generate higher-value chemical products. Herein, we fabricated a porous copper electrode capable of catalyzing the reduction of carbon dioxide into higher-value products, such as ethylene, ethanol and propanol. We investigated the formation of the foams under different conditions, not only analyzing their morphological and crystal structure, but also documenting their performance as a catalyst. In particular, we studied the response of the foams to CO2 electrolysis, including the effect of urea as a potential additive to enhance CO2 catalysis. Before electrolysis, the pristine and urea-modified foam copper electrodes consisted of a mixture of cuboctahedra and dendrites. After 35 min of electrolysis, the cuboctahedra and dendrites underwent structural rearrangement affecting catalysis performance. We found that alterations in the morphology, crystallinity and surface composition of the catalyst were conducive to the deactivation of the copper foams.

scholarly journals Investigating Lignin-Derived Monomers and Oligomers in Low-Molecular-Weight Fractions Separated from Depolymerized Black Liquor Retentate by Membrane Filtration

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2887
Author(s):  
Kena Li ◽  
Jens Prothmann ◽  
Margareta Sandahl ◽  
Sara Blomberg ◽  
Charlotta Turner ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Performance ◽  
Membrane Filtration ◽  
Black Liquor ◽  
Complex Mixture ◽  
Value Added ◽  
Kraft Pulping ◽  
Classification Model ◽  
Low Molecular Weight ◽  
Chemical Complexity

Base-catalyzed depolymerization of black liquor retentate (BLR) from the kraft pulping process, followed by ultrafiltration, has been suggested as a means of obtaining low-molecular-weight (LMW) compounds. The chemical complexity of BLR, which consists of a mixture of softwood and hardwood lignin that has undergone several kinds of treatment, leads to a complex mixture of LMW compounds, making the separation of components for the formation of value-added chemicals more difficult. Identifying the phenolic compounds in the LMW fractions obtained under different depolymerization conditions is essential for the upgrading process. In this study, a state-of-the-art nontargeted analysis method using ultra-high-performance supercritical fluid chromatography coupled to high-resolution multiple-stage tandem mass spectrometry (UHPSFC/HRMSn) combined with a Kendrick mass defect-based classification model was applied to analyze the monomers and oligomers in the LMW fractions separated from BLR samples depolymerized at 170–210 °C. The most common phenolic compound types were dimers, followed by monomers. A second round of depolymerization yielded low amounts of monomers and dimers, while a high number of trimers were formed, thought to be the result of repolymerization.

scholarly journals The metabolism of cholesterol in the presence of liver mitochondria from normal and thyroxine-treated rats

1965 ◽  
Vol 94 (3) ◽  
pp. 594-603 ◽  
Author(s):  
KA Mitropoulos ◽  
NB Myant
Keyword(s):  
Carbon Dioxide ◽  
Steam Distillation ◽  
Liver Mitochondria ◽  
Incubation Mixture ◽  
Side Chain ◽  
Volatile Fraction ◽  
Low Molecular Weight ◽  
Butanol Extract ◽  
Rate Limiting ◽  
Layer Chromatography

1. [26-(14)C]- and [4-(14)C]-Cholesterol were incubated with liver mitochondria from normal and thyroxine-treated rats, and the radioactivity was measured in the carbon dioxide evolved during the incubation, in a butanol extract of the incubation mixture and in a volatile fraction containing substances of low molecular weight derived from the side chain of cholesterol. The butanol extract was separated by paper chromatography into three radioactive fractions, one of which contained the steroids more polar than cholesterol. 2. The butanol extract from incubations with [4-(14)C]cholesterol contained a radioactive substance moving with the same R(F) as cholic acid on thin-layer chromatography. 3. After incubation with [26-(14)C]-cholesterol, 60-80% of the radioactivity extracted by steam-distillation of the incubation mixture at acid pH was recovered as [(14)C]propionic acid. 4. In the presence of [26-(14)C]cholesterol, mitochondria from thyroxine-treated rats produced more radioactivity in carbon dioxide and in the volatile fraction, and less radioactivity in the fraction containing the polar steroids, than did mitochondria from normal rats. In the presence of [4-(14)C]cholesterol, mitochondria from thyroxine-treated rats produced the same amount of radioactivity in the polar steroids as did normal mitochondria. 5. Thyroxine treatment had no effect on the capacity of the mitochondria to oxidize propionate to carbon dioxide. 6. These results are best explained by supposing that thyroxine stimulates a rate-limiting reaction leading to the cleavage of the side chain of cholesterol, but has little or no influence on the hydroxylations of the ring system or on the oxidation of the C(3) fragment removed from the side chain.

scholarly journals Strengthening epoxy adhesives at elevated temperatures based on dynamic disulfide bonds

2020 ◽  
Vol 1 (9) ◽  
pp. 3182-3188
Author(s):  
Hsing-Ying Tsai ◽  
Yasuyuki Nakamura ◽  
Takehiro Fujita ◽  
Masanobu Naito
Keyword(s):  
Glass Transition ◽  
Disulfide Bonds ◽  
Epoxy Resins ◽  
Elevated Temperatures ◽  
Adhesive Properties ◽  
Epoxy Adhesives ◽  
Transition Points ◽  
Increasing Temperature

Epoxy resins incorporating aromatic disulfide bonds demonstrated improved adhesive properties with increasing temperature below their glass transition points.

Sign in / Sign up

Export Citation Format

Share Document