A mass spectrometric study of the allyl radical interaction with oxides: MoO3

1979 ◽  
Vol 44 (3) ◽  
pp. 673-683 ◽  
Author(s):  
Zdeněk Dolejšek ◽  
Jana Nováková
Keyword(s):  
Mass Spectrometer ◽  
Main Product ◽  
Allyl Bromide ◽  
High Vacuum ◽  
Mass Spectrometric Study ◽  
Catalytic Reactor ◽  
Reaction Products ◽  
Allyl Radical ◽  
The Difference ◽  
Radical Interaction

Allyl radicals prepared by pyrolysis of 1,5-hexadiene or allyl bromide in a quartz pyrolyzer were directed at pressures of around 0.1 Pa through an unheated reactor filled loosely with pieces of MoO3. All components of the gaseous phase were analyzed by means of a mass spectrometer; the pyrolyzer and the catalytic reactor were placed in a high vacuum part of the mass spectrometer close to its ionization chamber so that unstable reaction products could also be detected. Acrolein was found to be the main product of the catalytic reaction between MoO3 and allyl radicals; other products were propylene, CO and CO2. The above mentioned interaction of allyl radicals with unheated MoO3 was compared with (i) the interaction of unheated MoO3 with vapours of 1,5-hexadiene or allyl bromide heated below the respective temperature of pyrolysis; (ii) the interaction of MoO3 heated to 510 K with unheated vapours of 1,5-hexadiene or allyl bromide. The difference between these three types of interactions and differences in the behaviour of 1,5-hexadiene and allyl bromide are discussed.

Mass spectrometric study of allyl radical, allyl bromide and 1,5-hexadiene interactions with oxides; Cobalt suboxide Co3O4

1979 ◽  
Vol 44 (7) ◽  
pp. 2009-2014 ◽  
Author(s):  
Jana Nováková ◽  
Zdeněk Dolejšek
Keyword(s):  
Room Temperature ◽  
Allyl Bromide ◽  
Catalytic Properties ◽  
Mass Spectrometric Study ◽  
Spectrometric Study ◽  
Flow Conditions ◽  
Allyl Radical ◽  
Knudsen Flow ◽  
Thermally Activated ◽  
Radical Interaction

Products of (a) allyl radical interaction with unheated Co3O4, (b) thermally activated 1,5-hexadiene or thermally activated allyl bromide with unheated Co3O4, (c) moderately heated Co3O4 with unheated 1,5-hexadiene or allyl bromide were studied under Knudsen flow conditions. Cobalt suboxide Co3O4, a typical catalyst of deep oxidations yielded acrolein in reaction with allyl radicals as early as at the room temperature of the catalyst. A similar acrolein formation was also observed in the allyl radical interaction with other oxides exhibiting different catalytic properties. It appears that acrolein is in general the primary product of the allyl radical interaction with the oxides. The results are discussed and compared with previous data obtained with MoO3.

Reuse of Fried Oil to Obtain Biodiesel: Zeolites Y as a Catalyst

2007 ◽  
Vol 5 (1) ◽  
Author(s):  
A. Brito ◽  
M. E. Borges ◽  
R. Arvelo ◽  
F. Garcia ◽  
M. C. Diaz ◽  
...  
Keyword(s):  
Fixed Bed ◽  
Weight Ratio ◽  
Degree Of Conversion ◽  
Transesterification Reaction ◽  
Molar Ratio ◽  
Catalytic Reactor ◽  
Reaction Products ◽  
Waste Oil ◽  
Catalytic Effects ◽  
Fried Oil

The transesterification reaction is the most utilized process to obtain biodiesel. Fried oil transesterification reactions with methanol have been studied using several zeolites Y and interchanged with CsCl and KOH. The reaction has been carried out both in a slurry reactor and a fixed bed catalytic reactor. The catalytic effects of zeolites have been tested within a temperature range of 60-476°C, 2.5-5% catalyst/waste oil weight ratio, and 6:1 - 100:1 methanol/oil molar ratio. Cosolvents (THF, n-hexane) in the reaction feedstock effect have also been studied as well as catalyst regeneration effects. Viscosity of both the oil and the transesterification reaction products was determined as an initial guide to investigate the degree of conversion to biodiesel as well as FAME content by GC. When interchanged zeolites are used conversions are improved, getting the best yields (98% FAME) for the Y756 zeolite interchanged with KOH. Viscosities of the reaction product obtained reached values next to diesel standard ones.

scholarly journals Nitrile versus isonitrile adsorption at interstellar grain surfaces

2017 ◽  
Vol 608 ◽  
pp. A50 ◽  
Author(s):  
M. Bertin ◽  
M. Doronin ◽  
X. Michaut ◽  
L. Philippe ◽  
A. Markovits ◽  
...  
Keyword(s):  
Density Functional ◽  
Surface Defects ◽  
High Vacuum ◽  
Solid Support ◽  
Ultra High Vacuum ◽  
Structural Defects ◽  
Adsorption Energies ◽  
The Difference ◽  
Temperature Programmed ◽  
Open Question

Context. Almost 20% of the ~200 different species detected in the interstellar and circumstellar media present a carbon atom linked to nitrogen by a triple bond. Of these 37 molecules, 30 are nitrile R-CN compounds, the remaining 7 belonging to the isonitrile R-NC family. How these species behave in their interactions with the grain surfaces is still an open question. Aims. In a previous work, we have investigated whether the difference between nitrile and isonitrile functional groups may induce differences in the adsorption energies of the related isomers at the surfaces of interstellar grains of various nature and morphologies. This study is a follow up of this work, where we focus on the adsorption on carbonaceous aromatic surfaces. Methods. The question is addressed by means of a concerted experimental and theoretical approach of the adsorption energies of CH3CN and CH3NC on the surface of graphite (with and without surface defects). The experimental determination of the molecule and surface interaction energies is carried out using temperature-programmed desorption in an ultra-high vacuum between 70 and 160 K. Theoretically, the question is addressed using first-principle periodic density functional theory to represent the organised solid support. Results. The adsorption energy of each compound is found to be very sensitive to the structural defects of the aromatic carbonaceous surface: these defects, expected to be present in a large numbers and great diversity on a realistic surface, significantly increase the average adsorption energies to more than 50% as compared to adsorption on perfect graphene planes. The most stable isomer (CH3CN) interacts more efficiently with the carbonaceous solid support than the higher energy isomer (CH3NC), however.

scholarly journals Quantum Chemistry Estimation of Adhesion Strength of Hydroxyapatite with Titanium Substrate

2021 ◽  
Vol 03 (04) ◽  
pp. 1-1
Author(s):  
Alla V. Balueva ◽  
◽  
Ilia N. Dashevskiy ◽  
Patricia Todebush ◽  
◽  
...  
Keyword(s):  
Adhesion Strength ◽  
Density Functional ◽  
Reaction Path ◽  
Titanium Substrate ◽  
Reaction Products ◽  
Functional Theory ◽  
Standard Material ◽  
The Difference ◽  
Ground Energy ◽  
Biocompatible Coatings

One of the ways to improve the fusion of an implant with bone tissue is through the use of biocompatible coatings, in particular, hydroxyapatite (HAp). It is important to assess the strength of the HAp adhesion to the implant. The measure of the strength of the bond of the coating with the substrate is the energy of this bond. Using density functional theory and molecular dynamics, the reaction path, reaction products, oscillation frequency, activation energy and bond energy between different combinations of component anions HAp and Ti (II) – the standard material of implants – are calculated. Using the computational chemistry software suite Gaussian 09 (Revision C.01 was used), the stable configurations of the reactants and products are found, and the binding energy of hydroxyapatite and titanium is then calculated based on the difference in ground energy of reactants and ground energy of products. Thus, the method of adhesion strength estimation between HAp coatings and Ti is proposed based on numerical calculations using MD software, and suggestions are provided on which conditions would be the best for optimal binding strength.

scholarly journals On a new approach to assessing the energy characteristics of substances

2019 ◽  
Vol 124 ◽  
pp. 01017
Author(s):  
O. S. Sirotkin ◽  
A. M. Pavlova ◽  
R. O. Sirotkin ◽  
A. E. Buntin
Keyword(s):  
Energy Production ◽  
Chemical Interaction ◽  
Heat Of Formation ◽  
Redox Properties ◽  
Chemical Components ◽  
Reaction Products ◽  
Energy Characteristics ◽  
New Approach ◽  
Production Technologies ◽  
The Difference

Within the unified model of chemical bonding and methods of quantitative assessment of components of mixed chemical interaction between the elements in compounds, developed by the authors, a new approach was developed to assess the structural and energy characteristics of substances and fuels. It comprises establishing a correlation between the difference of bonds’ chemical components of reactants and end products. Changes in the chemical bond components affect such characteristics of chemical reactions as the heat of formation of the reaction products, their redox properties, whether reaction is endoor exothermic, as well as the heat of fuel combustion reactions. This approach is an additional reserve for improving the methods for assessing the energy characteristics of fuels and increasing the efficiency of energy production technologies.

scholarly journals Effect of the MgO/Silica Fume Ratio on the Reaction Process of the MgO–SiO2–H2O System

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 80 ◽  
Author(s):  
Zhaoheng Li ◽  
Yudong Xu ◽  
Hao Liu ◽  
Jianwei Zhang ◽  
Jiangxiong Wei ◽  
...  
Keyword(s):  
Reaction Kinetics ◽  
Silica Fume ◽  
Main Product ◽  
Magnesium Silicate ◽  
Reaction Process ◽  
Reaction Products ◽  
Degree Of Reaction ◽  
Reaction Thermodynamics ◽  
Experimental Values ◽  
Kinetics Of

In order to clarify the effect of the MgO–silica fume (SF) ratio on the reaction process of the MgO–SiO2–H2O system, the reaction products and degree of reaction were characterized. Furthermore, the parameters of the reaction thermodynamics were calculated and the reaction kinetics were deduced. The results indicate that a large amount of Mg(OH)2 and small quantities of magnesium silicate hydrate (M–S–H) gels were generated upon dissolution of MgO. However, the M–S–H gels were continuously generated until the SF or Mg(OH)2 was consumed completely. For a MgO dosage less than 50% of the total MgO–SiO2–H2O system, the main product was M–S–H gel, while for a MgO dosage greater than 50%, the main product was Mg(OH)2. The results indicate that M–S–H gels have greater stability than Mg(OH)2, and the final reaction product was prone to be M–S–H gels. Based on the experimental values, an equation is proposed for the reaction kinetics of MgO.

Microstructure Characterization of the Reaction Interface between CBN Grain and Titanium-Deposited Film

2012 ◽  
Vol 538-541 ◽  
pp. 166-171
Author(s):  
Wen Feng Ding ◽  
Yang Min Liang ◽  
Jian He ◽  
Li Tang ◽  
Jie Yu ◽  
...  
Keyword(s):  
Heating Temperature ◽  
Cubic Boron Nitride ◽  
High Vacuum ◽  
Reaction Products ◽  
X Ray Diffraction ◽  
X Ray ◽  
Energy Dispersion Spectrometer ◽  
Heat Treated ◽  
Deposited Film

Cubic boron nitride (CBN) abrasive grains with surface titanium-deposited film were heat-treated during 550-950°C for 60 min under high vacuum circumstance. Detailed interfacial compounds analysis by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersion spectrometer (EDS), differential thermal analysis (DTA) indicates that the interfacial reactions are much dependent on the heating temperature to some extents, and the reaction products, TiN, TiB2 and TiB chiefly form the network structure. In particular, at 950°C the transition layers with excellent performance, CBN/TiB2/TiB/(TiB+TiN)/TiN/CBN, is realized.

scholarly journals An Ultra-high Vacuum Mass Spectrometer

Shinku ◽  
1960 ◽  
Vol 3 (3) ◽  
pp. 96-103 ◽  
Author(s):  
Koji KAWASAKI ◽  
Toshio SUGITA ◽  
Atsushi FUJINAGA ◽  
Masayuki GOTO ◽  
Junjiro KAI
Keyword(s):  
Mass Spectrometer ◽  
High Vacuum ◽  
Ultra High Vacuum
Sign in / Sign up

Export Citation Format

Share Document