scholarly journals Preparation of Novel High-Temperature Polyol Esters from Vegetable Oils

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Can Liu ◽  
Jing Liu ◽  
Lanqing Ma ◽  
Long Rong
Keyword(s):  
High Temperature ◽  
Decomposition Temperature ◽  
Synthesis Process ◽  
Hydroxyl Groups ◽  
Jatropha Oil ◽  
Chemical Modifications ◽  
Polyol Ester ◽  
Polyol Esters ◽  
Oil Hydrolysis ◽  
Lower Peroxide

The aim of this work was to synthesize a high-temperature polyol ester from Jatropha oil. The synthesis process was accomplished via chemical modifications involving epoxidation to remove the double bonds in Jatropha oil, hydrolysis to add hydroxyl groups, and then esterification with pentaerythritol to form the saturated polyol ester. The high decomposition temperature 359°C of the polyol ester was determined by thermogravimetric analysis. The lower peroxide value 0.07 meq/kg and iodine value 0.02 mg I2/100 g of the polyol esters were also determined.

scholarly journals High-Temperature Synthesis of Metal–Matrix Composites (Ni-Ti)-TiB2

2021 ◽  
Vol 11 (5) ◽  
pp. 2426
Author(s):  
Vladimir Promakhov ◽  
Alexey Matveev ◽  
Nikita Schulz ◽  
Mikhail Grigoriev ◽  
Andrey Olisov ◽  
...  
Keyword(s):  
High Temperature ◽  
Composite Materials ◽  
Metal Matrix Composite ◽  
Matrix Composite ◽  
Metal Matrix ◽  
Average Particle Size ◽  
Synthesis Process ◽  
Average Particle ◽  
Temperature Synthesis ◽  
High Temperature Synthesis

Currently, metal–matrix composite materials are some of the most promising types of materials, and they combine the advantages of a metal matrix and reinforcing particles/fibres. Within the framework of this article, the high-temperature synthesis of metal–matrix composite materials based on the (Ni-Ti)-TiB2 system was studied. The selected approaches make it possible to obtain composite materials of various compositions without contamination and with a high degree of energy efficiency during production processes. Combustion processes in the samples of a 63.5 wt.% NiB + 36.5 wt.% Ti mixture and the phase composition and structure of the synthesis products were researched. It has been established that the synthesis process in the samples proceeds via the spin combustion mechanism. It has been shown that self-propagating high-temperature synthesis (SHS) powder particles have a composite structure and consist of a Ni-Ti matrix and TiB2 reinforcement inclusions that are uniformly distributed inside it. The inclusion size lies in the range between 0.1 and 4 µm, and the average particle size is 0.57 µm. The obtained metal-matrix composite materials can be used in additive manufacturing technologies as ligatures for heat-resistant alloys, as well as for the synthesis of composites using traditional methods of powder metallurgy.

scholarly journals Stabilization of nickel-laden sludge by a high-temperature NiCr2O4 synthesis process

2011 ◽  
Vol 198 ◽  
pp. 356-361 ◽  
Author(s):  
Nien-Hsun Li ◽  
Yen-Hsin Chen ◽  
Ching-Yao Hu ◽  
Ching-Hong Hsieh ◽  
Shang-Lien Lo
Keyword(s):  
High Temperature ◽  
Synthesis Process

Effect of High-Temperature Defibration on the Chemical Structure of Hardwood

Holzforschung ◽  
2002 ◽  
Vol 56 (1) ◽  
pp. 51-59 ◽  
Author(s):  
P. Widsten ◽  
J.E. Laine ◽  
P. Qvintus-Leino ◽  
S. Tuominen
Keyword(s):  
High Temperature ◽  
Lignin Content ◽  
Bulk Composition ◽  
Chemical Properties ◽  
Water Extract ◽  
Fiber Surface ◽  
Phenolic Hydroxyl ◽  
Hydroxyl Groups ◽  
Surface Chemical ◽  
Alkyl Aryl

Summary The present paper aims at elucidating the effect of high-temperature defibration at different temperatures on the bulk and surface chemical properties of defibrated birch, aspen and eucalypt. The results indicate that defibration of these hardwoods results in partial depolymerization of fiber lignin via (homolytic) cleavage of interunit alkyl-aryl (β-O-4) ether bonds. This increases the phenolic hydroxyl content and produces relatively stable (phenoxy) radicals. Syringyl-type lignin is more extensively depolymerized than guaiacyl-type lignin. Defibration generates water-extractable material, which is enriched in hemicellulose-derived carbohydrates and has a substantial content of aromatic compounds rich in phenolic hydroxyl groups. The amount of water-extract and the extent of lignin interunit ether bond cleavage increase with an increase in defibration temperature. The differences between various hardwood species in this respect are small. The surface chemical composition of the fibers differs considerably from their bulk composition, but is not significantly influenced by variations in defibration temperature. Lipophilic extractives cover a large portion of the fiber surface, while the lignin content of lipophilic extractives-free fiber surfaces is 2–3 times as high as the bulk lignin content of the fibers.

scholarly journals SHS robust modes to restore molybdenum by combustion wave in MoO3 – Al system

2020 ◽  
Vol 15 (4) ◽  
pp. 27-32
Author(s):  
Irina V. Milyukova ◽  
Marina P. Boronenko
Keyword(s):  
Spectral Analysis ◽  
High Temperature ◽  
Combustion Wave ◽  
Synthesis Process ◽  
Temperature Synthesis ◽  
Preliminary Heating ◽  
X Ray ◽  
Molybdenum Metal ◽  
High Temperature Synthesis ◽  
Oxide Phases

The work is devoted to the technology for the reduction of molybdenum from oxides by the method of self-propagating high-temperature synthesis in the MoO3 AI system with the addition of aluminum. The experiment was carried out in two modes: in a reactor at different pressures without preliminary heating and in a furnace in air until the initiation of the SH-synthesis process. Samples of molybdenum metal were obtained in different synthesis modes. X-ray phase and X-ray spectral analysis showed that molybdenum is the main phase in the synthesized samples. The presence of slag oxide phases Al2O3 and MoO2 was detected.

Immobilization of Radioactive Wastes into Perovskite Synrock by the SHS Method

2005 ◽  
Vol 475-479 ◽  
pp. 1627-1630 ◽  
Author(s):  
Rui Zhu Zhang ◽  
Zhi Meng Guo ◽  
Cheng Chang Jia ◽  
Guangfeng Lu
Keyword(s):  
High Temperature ◽  
Synthesis Process ◽  
Temperature Synthesis ◽  
Geological Disposal ◽  
Major Phase ◽  
Leach Rate ◽  
High Temperature Synthesis ◽  
Waste Loading ◽  
Shs Method

This paper researched the fabrication of perovskite synrock by self-propagating high temperature synthesis (SHS) and the characterization of the products. This synthesis process is simpler, the fabricated synrock can immobilize waste loading up to 35wt% SrO with satisfied physical properties (density>4.2g•cm-3, open porosity<0.2%, Leach rate<1.0 g•m-2•d-1). The structure analyses by XRD and SEM/EDS show that the major phase is perovskite which well agrees with the design. It proves that SHS offer a suitable Sr-waste synroc which is favorable for geological disposal.

Recent Progress in Chemical Modification of the Natural Polysaccharide Guar Gum

2021 ◽  
Vol 18 ◽  
Author(s):  
Simran Kaur ◽  
Soumava Santra
Keyword(s):  
Chemical Modification ◽  
Recent Progress ◽  
Guar Gum ◽  
Biological Properties ◽  
Hydroxyl Groups ◽  
Chemical Modifications ◽  
Natural Polysaccharide ◽  
Potential Applications ◽  
Pharmaceutical Industries

: Guar gum (GG) is a natural heteropolysaccharide. Due to its non-toxic, eco-friendly, and biodegradable nature, GG has found wide applications in many areas, in particular food, paper, textile, petroleum, and pharmaceutical industries. Therefore, GG is often called “Black Gold” as well. Due to the presence of hydroxyl groups, GG can be modified by various methods. The physical and biological properties of GG can be modulated by chemical modifications. In this manuscript, various methods for the chemical modifications of GG have been discussed according to the type of modifications. Mechanistic insights have also been provided whenever possible. In addition, potential applications of new GG derivatives have also been briefly mentioned.

scholarly journals Electroanalytical Performance of Nitrogen-Doped Graphene Films Processed in One Step by Pulsed Laser Deposition Directly Coupled with Thermal Annealing

Materials ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 666 ◽  
Author(s):  
Florent Bourquard ◽  
Yannick Bleu ◽  
Anne-Sophie Loir ◽  
Borja Caja-Munoz ◽  
José Avila ◽  
...  
Keyword(s):  
High Temperature ◽  
Pulsed Laser Deposition ◽  
Graphene Film ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Synthesis Process ◽  
Nitrogen Doped ◽  
Nitrogen Doped Graphene ◽  
Doped Graphene ◽  
One Step

Graphene-based materials are widely studied to enable significant improvements in electroanalytical devices requiring new generations of robust, sensitive and low-cost electrodes. In this paper, we present a direct one-step route to synthetize a functional nitrogen-doped graphene film onto a Ni-covered silicon electrode substrate heated at high temperature, by pulsed laser deposition of carbon in the presence of a surrounding nitrogen atmosphere, with no post-deposition transfer of the film. With the ferrocene methanol system, the functionalized electrode exhibits excellent reversibility, close to the theoretical value of 59 mV, and very high sensitivity to hydrogen peroxide oxidation. Our electroanalytical results were correlated with the composition and nanoarchitecture of the N-doped graphene film containing 1.75 at % of nitrogen and identified as a few-layer defected and textured graphene film containing a balanced mixture of graphitic-N and pyrrolic-N chemical functions. The absence of nitrogen dopant in the graphene film considerably degraded some electroanalytical performances. Heat treatment extended beyond the high temperature graphene synthesis did not significantly improve any of the performances. This work contributes to a better understanding of the electrochemical mechanisms of doped graphene-based electrodes obtained by a direct and controlled synthesis process.

scholarly journals A Novel Sesquiterpene Polyol Ester from the Celastrus Rosthornianus with Anti-tumor Activities

2006 ◽  
Vol 1 (7) ◽  
pp. 1934578X0600100 ◽  
Author(s):  
Kuiwu Wang ◽  
Yuanjiang Pan
Keyword(s):  
Tumor Cell ◽  
Cell Lines ◽  
Human Tumor ◽  
2D Nmr ◽  
Spectroscopic Techniques ◽  
Tumor Cell Lines ◽  
Human Tumor Cell ◽  
Polyol Ester ◽  
Human Tumor Cell Lines ◽  
Polyol Esters

A new (1) and a known (2) β-dihydroagarofuran sesquiterpene polyol esters were isolated from Celastrus rosthornianus and their structures were established by 1D- and 2D-NMR spectroscopic techniques. The two compounds exhibited anti-tumor activities against a panel of human tumor cell lines.

FGM Fabrication by Combustion Synthesis

MRS Bulletin ◽  
1995 ◽  
Vol 20 (1) ◽  
pp. 52-53 ◽  
Author(s):  
Gregory C. Stangle ◽  
Yoshinari Miyamoto
Keyword(s):  
High Temperature ◽  
Combustion Synthesis ◽  
Volume Fraction ◽  
Synthesis Process ◽  
Composition Gradient ◽  
Synthesis Methods ◽  
High Temperature Synthesis ◽  
Exothermic Chemical Reaction ◽  
Reactant Powder ◽  
Refractory Ceramics

FGMs have been fabricated using the combustion synthesis (or self-propagating high-temperature synthesis (SHS)) process by exploiting a rapid and exothermic chemical reaction, in order to synthesize some (or all) of the constituents in an FGM to simultaneously increase its density. The thermal energy required to drive the process is derived from this internal, chemical source, rather than from an external and usually expensive source (e.g., a furnace). The combustion synthesis process is a powder-based process that has been used to synthesize over 300 compounds, and is particularly useful in preparing materials such as highly refractory ceramics and high-temperature intermetallics that are difficult to prepare by other synthesis methods. In addition, the process can be used to prepare ceramic-metal and ceramic-intermetallic composite materials. As a result, only slight modifications of the combustion synthesis are required to prepare functionally gradient materials from these same combinations of materials.Sample preparation begins by the creation of a series of mixtures from the powders that will react to form the constituent materials of the FGM sample. Each of these mixtures contains a slightly different percentage of reactants, so that each mixture will yield its own (predetermined) volume fraction of each of its constituents, following the combustion synthesis process. Prior to the combustion step, the samples are assembled by stacking layers of each of the reactant powder mixtures in appropriate amounts, in such a way that the multilayered powder mixture will faithfully produce the composition gradient that is required in the resultant FGM.

Sign in / Sign up

Export Citation Format

Share Document