Gas-phase reactions of 2-benzyl- and 2-benzoyl-phenoxyl radicals, and of 2-phenoxybenzyl radicals: examples of new hydrogen-transfer processes

1991 ◽  
pp. 385 ◽  
Author(s):  
J. I. G. Cadogan ◽  
H. Susan Hutchison ◽  
Hamish McNab
Keyword(s):  
Gas Phase ◽  
Hydrogen Transfer ◽  
Gas Phase Reactions ◽  
Phenoxyl Radicals ◽  
Transfer Processes

scholarly journals The HNO− radical anion: A proposed intermediate in diazeniumdiolate synthesis using nitric oxide and alkoxides

2018 ◽  
Vol 25 (1) ◽  
pp. 82-85 ◽  
Author(s):  
Zhe-Chen Wang ◽  
Ya-Ke Li ◽  
Sheng-Gui He ◽  
Veronica M Bierbaum
Keyword(s):  
Nitric Oxide ◽  
Reaction Mechanism ◽  
Gas Phase ◽  
Radical Anion ◽  
Room Temperature ◽  
Hydrogen Transfer ◽  
Gas Phase Reactions ◽  
Ionic Product

The strategy of synthesizing diazeniumdiolates (X–N(O)=NO−) through the coexistence of nitric oxide and alkoxides (RO−) was introduced by Wilhelm Traube 120 years ago. Today, despite the wide use of diazeniumdiolate derivatives to release nitric oxide in the treatment of cancer, the first step of the reaction mechanism for diazeniumdiolate synthesis remains a mystery and is thought to be complex. We have studied the gas-phase reactions of nitric oxide with alkoxides at room temperature. An electron-coupled hydrogen transfer is observed, and the radical anion HNO− is the only ionic product in these reactions. HNO− can further react with nitric oxide to form N2O and HO−.

Mathematical Modeling of Heat and Mass Transfer Processes During Pyrolysis and Combustion of a Single Biomass Particle

2012 ◽  
Author(s):  
Y. Haseli ◽  
J. A. van Oijen ◽  
L. P. H. de Goey
Keyword(s):  
Carbon Dioxide ◽  
Mass Transfer ◽  
Carbon Monoxide ◽  
Water Vapor ◽  
Gas Phase ◽  
Combustion Process ◽  
Combustion Model ◽  
Gas Phase Reactions ◽  
Transfer Processes ◽  
Mass Transfer Processes

A detailed mathematical model is developed for simulation of heat and mass transfer processes during the pyrolysis and combustion of a single biomass particle. The kinetic scheme of Shafizadeh and Chin is employed to describe the pyrolysis process. The light gases formed during the biomass pyrolysis is assumed to consist of methane, carbon dioxide, carbon monoxide, hydrogen and water vapor with given mass fractions relevant to those found in the experiments of high heating conditions. The combustion model takes into account the reactions of oxygen with methane, hydrogen, carbon monoxide, tar and char as well as gasification of char with water vapor and carbon dioxide. Appropriate correlations taken from past studies are used for computation of the rate of these reactions. The model allows calculation of time and space evolution of various parameters including biomass and char densities, gaseous species and temperature. Different experimental data reported in the literature are employed to validate the pyrolysis and combustion models. The reasonable agreement obtained between the predictions and measured data reveals that the presented model is capable of successfully capturing various experiments of wood particle undergoing a pyrolysis or combustion process. In particular, the role of gas phase reactions within and adjacent to particle on the combustion process is examined. The results indicate that for the case of small particles in the order of millimeter size and less, one may neglect any effects of gas phase reactions. However, for larger particles, a combustion model may need to include hydrogen oxidation and even carbon monoxide combustion reactions.

Effect of Niacin on Mitochondria of Allium Cepa Root Cells

1967 ◽  
Vol 25 ◽  
pp. 78-79
Author(s):  
M. Arif Hayat
Keyword(s):  
Nicotinamide Adenine Dinucleotide ◽  
Hydrogen Transfer ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Nicotinamide Adenine ◽  
Root Tips ◽  
Root Cells ◽  
Transfer Processes ◽  
Standard Procedures ◽  
A Cell ◽  
Critical Interest

Although it is recognized that niacin (pyridine-3-carboxylic acid), incorporated as the amide in nicotinamide adenine dinucleotide (NAD) or in nicotinamide adenine dinucleotide phosphate (NADP), is a cofactor in hydrogen transfer in numerous enzyme reactions in all organisms studied, virtually no information is available on the effect of this vitamin on a cell at the submicroscopic level. Since mitochondria act as sites for many hydrogen transfer processes, the possible response of mitochondria to niacin treatment is, therefore, of critical interest.Onion bulbs were placed on vials filled with double distilled water in the dark at 25°C. After two days the bulbs and newly developed root system were transferred to vials containing 0.1% niacin. Root tips were collected at ¼, ½, 1, 2, 4, and 8 hr. intervals after treatment. The tissues were fixed in glutaraldehyde-OsO4 as well as in 2% KMnO4 according to standard procedures. In both cases, the tissues were dehydrated in an acetone series and embedded in Reynolds' lead citrate for 3-10 minutes.

Gas-Phase Reactions

1981 ◽  
Author(s):  
Victor N. Kondratiev ◽  
Evgeniĭ E. Nikitin
Keyword(s):  
Gas Phase ◽  
Gas Phase Reactions
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