A Comparative Study of Cation and Anion Cluster Reaction Products:  The Reaction Mechanisms of Lead Clusters with Benzene in Gas Phase

2003 ◽  
Vol 107 (41) ◽  
pp. 8484-8491 ◽  
Author(s):  
Xiaopeng Xing ◽  
Zhixin Tian ◽  
Hongtao Liu ◽  
Zichao Tang
Keyword(s):  
Comparative Study ◽  
Gas Phase ◽  
Reaction Mechanisms ◽  
Reaction Products ◽  
Anion Cluster ◽  
Cluster Reaction

Comparative study of cw CO2 laser induced and SF6 sensitized decomposition of methyl iodides CH3I and CD3I

1985 ◽  
Vol 50 (1) ◽  
pp. 215-222 ◽  
Author(s):  
Jaroslav Rejnek ◽  
Pavel Engst ◽  
Marie Jakoubková ◽  
Milan Horák
Keyword(s):  
Comparative Study ◽  
Methyl Iodide ◽  
Co2 Laser ◽  
Reaction Mechanisms ◽  
Energy Levels ◽  
Wavelength Region ◽  
Reaction Products ◽  
Vibrationally Excited ◽  
Laser Spectrum ◽  
Cw Co2 Laser

The decomposition of methyl iodide-d3 initiated by the irradiation of a cw CO2 laser in the presence of SF6 proceeds under comparable conditions faster, particularly in the shorter wavelength region of the CO2 laser spectrum, than the decomposition of methyl iodide. The differences can be explained by the different distribution of energy levels of both reactants. Observable differences are also in the composition of the reaction products. All these facts indicate the participation of at least two reaction mechanisms, a radical one and and a molecular one, which can probably proceed via the collision of two vibrationally excited molecules of CX3I.

COMPUTER MODELING OF CHEMICAL EQUILIBRIUMS IN WO3–H2O SYSTEM

2017 ◽  
pp. 35-48 ◽  
Author(s):  
V.P. Bondarenko ◽  
O.O. Matviichuk
Keyword(s):  
Transition Temperature ◽  
Gas Phase ◽  
Single Phase ◽  
Reference Data ◽  
Maximum Amount ◽  
Reaction Products ◽  
Influence Of Temperature ◽  
Equilibrium Chemical ◽  
Program Data ◽  
Good Agreement

Detail investigation of equilibrium chemical reactions in WO3–H2O system using computer program FacktSage with the aim to establish influence of temperature and quantity of water on formation of compounds of H2WO4 and WO2(OH)2 as well as concomitant them compounds, evaporation products, decomposition and dissociation, that are contained in the program data base were carried out. Calculations in the temperature range from 100 to 3000 °С were carried out. The amount moles of water added to 1 mole of WO3 was varied from 0 to 27. It is found that the obtained data by the melting and evaporation temperatures of single-phase WO3 are in good agreement with the reference data and provide additionally detailed information on the composition of the gas phase. It was shown that under heating of 1 mole single-phase WO3 up to 3000 °С the predominant oxide that exist in gaseous phase is (WO3)2. Reactions of it formation from other oxides ((WO3)3 and (WO3)4) were proposed. It was established that compound H2WO4 is stable and it is decomposed on WO3 and H2O under 121 °C. Tungsten Oxide Hydrate WO2(OH)2 first appears under 400 °С and exists up to 3000 °С. Increasing quantity of Н2О in system leads to decreasing transition temperature of WO3 into both liquid and gaseous phases. It was established that adding to 1 mole WO3 26 mole H2O maximum amount (0,9044–0,9171 mole) WO2(OH)2 under temperatures 1400–1600 °С can be obtained, wherein the melting stage of WO3 is omitted. Obtained data also allowed to state that that from 121 till 400 °С WO3–Н2O the section in the О–W–H ternary system is partially quasi-binary because under these temperatures in the system only WO3 and Н2O are present. Under higher temperatures WO3–Н2O section becomes not quasi-binary since in the reaction products WO3 with Н2O except WO3 and Н2O, there are significant amounts of WO2(OH)2, (WO3)2, (WO3)3, (WO3)4 and a small amount of atoms and other compounds. Bibl. 12, Fig. 6, Tab. 5.

Comparative Study of Mono- and Dinuclear Complexes of Late 3d-Metal Chlorides withN,N-Dimethylformamide in the Gas phase†

2011 ◽  
Vol 50 (3) ◽  
pp. 771-782 ◽  
Author(s):  
Lucie Ducháčková ◽  
Jana Roithová ◽  
Petr Milko ◽  
Jan Žabka ◽  
Nikos Tsierkezos ◽  
...  
Keyword(s):  
Comparative Study ◽  
Gas Phase ◽  
Dinuclear Complexes ◽  
Metal Chlorides

Comparative Study of GaN Growth Process by MOVPE

1999 ◽  
Vol 572 ◽  
Author(s):  
Jingxi Sun ◽  
J. M. Redwing ◽  
T. F. Kuech
Keyword(s):  
High Temperature ◽  
Comparative Study ◽  
Gas Phase ◽  
Residence Time ◽  
Gas Flow ◽  
Flow Sheet ◽  
Flow Zone ◽  
High Quality ◽  
Phase Temperature ◽  
High Temperature Gas

ABSTRACTA comparative study of two different MOVPE reactors used for GaN growth is presented. Computational fluid dynamics (CFD) was used to determine common gas phase and fluid flow behaviors within these reactors. This paper focuses on the common thermal fluid features of these two MOVPE reactors with different geometries and operating pressures that can grow device-quality GaN-based materials. Our study clearly shows that several growth conditions must be achieved in order to grow high quality GaN materials. The high-temperature gas flow zone must be limited to a very thin flow sheet above the susceptor, while the bulk gas phase temperature must be very low to prevent extensive pre-deposition reactions. These conditions lead to higher growth rates and improved material quality. A certain range of gas flow velocity inside the high-temperature gas flow zone is also required in order to minimize the residence time and improve the growth uniformity. These conditions can be achieved by the use of either a novel reactor structure such as a two-flow approach or by specific flow conditions. The quantitative ranges of flow velocities, gas phase temperature, and residence time required in these reactors to achieve high quality material and uniform growth are given.

A comparative study of gas phase esterification on solid acid catalysts

2007 ◽  
Vol 114 (3-4) ◽  
pp. 122-128 ◽  
Author(s):  
Kaewta Suwannakarn ◽  
Edgar Lotero ◽  
James G. Goodwin
Keyword(s):  
Comparative Study ◽  
Gas Phase ◽  
Solid Acid ◽  
Solid Acid Catalysts ◽  
Acid Catalysts

Gas-phase oxidation of butene-2

1958 ◽  
Vol 244 (1238) ◽  
pp. 331-344 ◽  
Keyword(s):  
Gas Phase ◽  
Pressure Change ◽  
Reaction Products ◽  
Peroxide Formation ◽  
Time Curve ◽  
Pressure Time ◽  
Initial Oxygen ◽  
Gas Phase Oxidation ◽  
Reactive Radicals ◽  
Reaction Processes

The gas-phase thermal oxidation of butene-2 has been examined over the temperature range 289 to 395°C. No difference in behaviour of the cis and trans forms could be detected. At the higher temperatures the reaction resembled that of the oxidation of propylene in the shape of the pressure-time curve and in the identity of many of the reaction products. At the lower temperatures a decrease in pressure partly due to peroxide formation followed the induction period, and by the end of this time much of the initial oxygen had been consumed. At all temperatures excess olefin produced an apparent inhibiting effect manifested by a decreased yield of carbon monoxide and a fall-off in the maximum rate of pressure change and total pressure change. Reaction processes are discussed, and it is suggested that a peroxide precedes the formation of acetaldehyde. Branching occurs largely through reaction of acetyl radicals produced from the acetaldehyde. The inhibiting effects produced by excess olefin are attributed to the replacement of reactive radicals by the less reactive allylic-type radicals, and the addition reactions of olefin at higher olefin concentrations lead to polymerization and a low or negative overall pressure change.

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