Reaction of oxygen atoms with ethanol

1967 ◽  
Vol 45 (16) ◽  
pp. 1845-1861 ◽  
Author(s):  
A. Kato ◽  
R. J. Cvetanović
Keyword(s):  
Rate Constant ◽  
Vapor Phase ◽  
Room Temperature ◽  
Initial Reaction ◽  
Reaction Products ◽  
Absolute Value ◽  
Oxygen Atoms

Reaction of O(3P) atoms with ethanol in the vapor phase has been studied at room temperature. The principal initial reaction products are water, acetaldehyde, and 2,3-butanediol. The data are consistent with abstraction of an α-hydrogen from ethanol as the primary step in the reaction. Ethanol is found to react with O(3P) atoms about 3.5 times less rapidly than acetaldehyde. The approximate absolute value of the rate constant of the ethanol reaction at 25 °C is 6.2 × 1010 cm3 mole−1 s−1.As a corollary to the investigation of the reaction of oxygen atoms with ethanol, a brief study has been made of the mercury Hg 6(3P1) photosensitized decomposition of ethanol at room temperature.

scholarly journals Control of regioselectivity in reactions of dialkylstannylene acetals. Part II. NMR results and mechanistic analysis

1994 ◽  
Vol 72 (12) ◽  
pp. 2405-2415 ◽  
Author(s):  
Xianqi Kong ◽  
T. Bruce Grindley
Keyword(s):  
Nmr Spectra ◽  
Room Temperature ◽  
General Scheme ◽  
Preceding Paper ◽  
Initial Reaction ◽  
Reaction Intermediates ◽  
Oxidation Reactions ◽  
Kinetically Controlled ◽  
Mechanistic Analysis ◽  
Oxygen Atoms

The 119Sn NMR spectra of dialkylstannylene acetals derived from a number of carbohydrate-based terminal 1,2-diols have been recorded. The spectra of chloroform-d solutions at room temperature of most of these dialkylstannylene acetals were consistent with the presence of single symmetric dimers only although some did contain small proportions of higher oligomers. A general mechanistic scheme is presented that explains the regioselectivity of p-toluenesulfonation reactions of dialkylstannylene acetals presented in the preceding paper. In the scheme, the reaction intermediates are the dialkylstannylene acetal dimers. For p-toluenesulfonation reactions, equilibration between the three possible dimers is faster than reaction with p-toluenesulfonyl chloride. Reaction regioselectivity depends both on the position of the dimer equilibrium and on the rates of reaction of individual dicoordinate oxygen atoms in the dimers. The general scheme was also used to explain the regioselectivity obtained for the very fast oxidation reactions of dialkylstannylene acetals with bromine or N-bromosuccinimide. In these kinetically controlled reactions, regiochemistry is determined by the initial reaction of dicoordinate oxygen atoms in the most populated dimer(s) with the electrophilic oxidizing reagent.

The Kinetics of Inhibition of the Action of Thrombin by the Fibrinopeptides Formed during the Clotting of Fibrinogen

1966 ◽  
Vol 16 (01/02) ◽  
pp. 277-295 ◽  
Author(s):  
A Silver ◽  
M Murray
Keyword(s):  
Amino Acids ◽  
Competitive Inhibition ◽  
Amorphous Material ◽  
Peptide Bond ◽  
Initial Reaction ◽  
Reaction Products ◽  
Coagulation Mechanism ◽  
Kinetics Of ◽  
Kinetics Of Inhibition ◽  
Burk Plot

SummaryVarious investigators have separated the coagulation products formed when fibrinogen is clotted with thrombin and identified fibrinopeptides A and B. Two other peaks are observed in the chromatogram of the products of coagulation, but these have mostly been dismissed by other workers. They have been identified by us as amino acids, smaller peptides and amorphous material (37). We have re-chromatographed these peaks and identified several amino acids. In a closed system of fibrinogen and thrombin, the only reaction products should be fibrin and peptide A and peptide B. This reasoning has come about because thrombin has been reported to be specific for the glycyl-arginyl peptide bond. It is suggested that thrombin also breaks other peptide linkages and the Peptide A and Peptide B are attacked by thrombin to yield proteolytic products. Thrombin is therefore probably not specific for the glycyl-arginyl bond but will react on other linkages as well.If the aforementioned is correct then the fibrinopeptides A and B would cause an inhibition with the coagulation mechanism itself. We have shown that an inhibition does occur. We suggest that there is an autoinhibition to the clotting mechanism that might be a control mechanism in the human body.The experiment was designed for coagulation to occur under controlled conditions of temperature and time. Purified reactants were used. We assembled an apparatus to record visually the speed of the initial reaction, the rate of the reaction, and the density of the final clot formed after a specific time.The figures we derived made available to us data whereby we could calculate and plot the information to show the mechanism and suggest that such an inhibition does exist and also further suggest that it might be competitive.In order to prove true competitive inhibition it is necessary to fulfill the criteria of the Lineweaver-Burk plot. This has been done. We have also satisfied other criteria of Dixon (29) and Bergman (31) that suggest true competitive inhibition.

On the Chemistry of Tetrabenzyl Thiuram Disulfide and Tetramethyl Thiuram Disulfide with Bis (Triethoxysilylpropyl) Tetrasulfide in Silica Compounds

2003 ◽  
Vol 76 (4) ◽  
pp. 876-891 ◽  
Author(s):  
R. N. Datta ◽  
A. G. Talma ◽  
S. Datta ◽  
P. G. J. Nieuwenhuis ◽  
W. J. Nijenhuis ◽  
...  
Keyword(s):  
High Performance ◽  
Room Temperature ◽  
Succinic Anhydride ◽  
Dynamic Properties ◽  
The Other ◽  
Resonance Spectroscopy ◽  
Reaction Products ◽  
Negative Effect ◽  
Higher Temperature ◽  
Analytical Tools

Abstract The use of thiurams such as Tetramethyl thiuram disulfide (TMTD) or Tetrabenzyl thiuram disulfide (TBzTD) has been explored to achieve higher cure efficiency. The studies suggest that a clear difference exists between the effect of TMTD versus TBzTD. TMTD reacts with Bis (triethoxysilylpropyl) tetrasulfide (TESPT) and this reaction can take place even at room temperature. On the other hand, the reaction of TBzTD with TESPT is slow and takes place only at higher temperature. High Performance Liquid Chromatography (HPLC) with mass (MS) detection, Nuclear Magnetic Resonance Spectroscopy (NMR) and other analytical tools have been used to understand the differences between the reaction of TMTD and TESPT versus TBzTD and TESPT. The reaction products originating from these reactions are also identified. These studies indicate that unlike TMTD, TBzTD improves the cure efficiency allowing faster cure without significant effect on processing characteristics as well as dynamic properties. The loading of TESPT is reduced in a typical Green tire compound and the negative effect on viscosity is repaired by addition of anhydrides, such as succinic anhydride, maleic anhydride, etc.

Electron‐attachment rate constant for Cl2at room temperature and 250 °C

1979 ◽  
Vol 34 (3) ◽  
pp. 187-189 ◽  
Author(s):  
M. Rokni ◽  
J. H. Jacob ◽  
J. A. Mangano
Keyword(s):  
Rate Constant ◽  
Room Temperature ◽  
Electron Attachment ◽  
Attachment Rate

Room-Temperature GaAs/AlGaAs Quantum Cascade Lasers Grown by Metal–Organic Vapor Phase Epitaxy

2011 ◽  
Vol 23 (12) ◽  
pp. 774-776 ◽  
Author(s):  
A B Krysa ◽  
D G Revin ◽  
J P Commin ◽  
C N Atkins ◽  
K Kennedy ◽  
...  
Keyword(s):  
Vapor Phase ◽  
Room Temperature ◽  
Quantum Cascade Lasers ◽  
Vapor Phase Epitaxy ◽  
Quantum Cascade ◽  
Organic Vapor ◽  
Metal Organic ◽  
Cascade Lasers

REACTION OF OXYGEN ATOMS WITH BUTADIENE

1960 ◽  
Vol 38 (11) ◽  
pp. 2187-2195 ◽  
Author(s):  
R. J. Cvetanović ◽  
L. C. Doyle
Keyword(s):  
Pressure Dependence ◽  
Rate Constants ◽  
Room Temperature ◽  
Relative Rate ◽  
Excess Energy ◽  
General Mechanism ◽  
Arrhenius Parameters ◽  
Heats Of Reaction ◽  
Relative Rate Constants ◽  
Oxygen Atoms

Reaction of oxygen atoms with 1,3-butadiene has been investigated at room temperature. It is found that it conforms to the general mechanism established previously for the analogous reactions of monoolefins. Only 1,2-addition occurs, and the addition products, butadiene monoxide and 3-butenal, possess excess energy when formed as a result of high heats of reaction. The pressure dependence of the formation of the addition products yields the values of the "lifetimes" of the initially produced "hot" molecules. The relative rate constants have been determined at 25 and 127 °C and from these the relative values of the Arrhenius parameters have been calculated.

N-type Ba0.2Co4Sb11.5Te0.5: Optimization of thermoelectric properties by different pressures

2019 ◽  
Vol 33 (03) ◽  
pp. 1950027 ◽  
Author(s):  
Jiaxiang Chen ◽  
Xiaopeng Jia ◽  
Yuewen Zhang ◽  
Haiqiang Liu ◽  
Baomin Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Seebeck Coefficient ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Absolute Value ◽  
X Ray ◽  
Coefficient Increase ◽  
Maximum Power Factor ◽  
Scanning Electron

The polycrystalline skutterudite [Formula: see text] were successfully synthesized from 1.5 GPa to 3.5 GPa by the high pressure and high temperature (HPHT) method. Negative Seebeck coefficient confirmed the n-type conductivity of all samples. The phase compositions of samples were investigated by X-ray diffraction (XRD) and the microstructures were observed by scanning electron microscopy (SEM). It was found that the grains appeared smaller and the grain boundaries became more abundant when pressures were higher. We measured the electrical properties from room temperature to 723 K. Both the electrical resistivity and absolute value of Seebeck coefficient increase with the increasing synthetic pressure. At 723 K, the maximum power factor of [Formula: see text] was obtained for the sample synthesized under 3 GPa. The maximum ZT value of 0.61 was reached by [Formula: see text] synthesized under 3 GPa and measured at 723 K.

scholarly journals Microstructure Features of Ternary Alkali-activated Binder Based on Tungsten Mining Waste, Slag and Metakaolin

2020 ◽  
Author(s):  
Naim Sedira ◽  
João Castro-Gomes
Keyword(s):  
Sodium Silicate ◽  
Room Temperature ◽  
Mining Waste ◽  
Dense Matrix ◽  
Microstructural Properties ◽  
Reaction Products ◽  
Granulated Blast Furnace Slag ◽  
Alkaline Activator ◽  
Furnace Slag ◽  
Alkali Activated

This study determines the effect of ground granulated blast furnace slag (GGBFS) and metakaolin (MK) on the microstructural properties of the tungsten mining waste-based alkali-activated binder (TMWM). During this investigation, TMWM was partially replaced with 10 wt.% GGBFS and 10 wt.% MK to improve the microstructure of the binder. In order to understand the effect of the substitutions on the microstructure, two pastes were produced to make a comparative study between the sample contain 100% TMWM and the ternary precursors. Both precursors were activated using a combination of alkaline activator solutions (sodium silicate and sodium hydroxide) with the ratio of 1:3 (66.6 wt.% sodium silicate combined with 33.33 wt.% of NaOH 8M). The alkali-activated mixes were cured in oven at temperature of 60 °C in the first day and at room temperature for the next 27 days. The reaction products N-A-S-H gel and (N,M)-A-S-H gel resulted from the alkaline activation reaction process. In addition, a formation of natrite (Na2CO3) with needles shape occurred as a reaction product of the fluorescence phenomena. However, a dense matrix resulted from the alkline activation of the ternary precursors containg different gels such as N-A-S-H, C-A-S-H and (N,M)-C-A-S-H gel, these results were obtained through SEM-EDS analyses, as well FTIR tests. Keywords: Mining Waste, Alkali-activated, Microstructure, Slag, Metakaolin

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