The gas-phase decomposition of ethyl bromide

1971 ◽  
Vol 24 (10) ◽  
pp. 2031
Author(s):  
DA Kairaitis ◽  
VR Stimson
Keyword(s):  
Gas Phase ◽  
Initial Rate ◽  
Hydrogen Bromide ◽  
Bromine Atom ◽  
Ethyl Bromide ◽  
Phase Decomposition ◽  
Unimolecular Decomposition ◽  
Chain Reaction ◽  
Insight Into

The gas-phase decomposition of ethyl bromide at 423� in the presence of both ethylene and hydrogen bromide has been investigated. These additives, which are also the products, each influence the rate strongly but in opposite ways. The variation of initial rate with reactant pressure is given by (P in cm) ������������� k1 (min-1) = 15.2x10-3+19.5x10-3(PEtBrPHBr/PEne)1/2 This has been interpreted in terms of a unimolecular decomposition together with a bromine atom carried chain reaction with simple steps that involve the products. Some insight into the unaccompanied decomposition has been gained. Some remarks about the role of olefinic inhibitors in reactions producing hydrogen bromide have been made.

Catalysis by hydrogen halides in the gas phase. XIX. 2,3-Dimethylbutan-2-ol and hydrogen bromide

1968 ◽  
Vol 21 (10) ◽  
pp. 2385 ◽  
Author(s):  
RL Johnson ◽  
VR Stimson
Keyword(s):  
Gas Phase ◽  
Arrhenius Equation ◽  
Hydrogen Bromide ◽  
Phase Decomposition ◽  
Hydrogen Halides ◽  
First Order

The gas-phase decomposition of 2,3-dimethylbutan-2-ol into 2,3-dimethylbut-1-ene, 2,3-dimethylbut-2-ene, and water, catalysed by hydrogen bromide at 303-400�, is described. The rate is first-order in each reactant and the Arrhenius equation k2 = 1011.88 exp(-26490/RT) sec-l ml mole-1 is followed. The olefins appear to be in their equilibrium proportions. The effects of substitutions in the alcohol at Cα and Cβ on the rate are discussed.

Di-imide: Some Physical and Chemical Properties, and the Kinetics and Stoichiometry of the Gas-phase Decomposition

1973 ◽  
Vol 51 (21) ◽  
pp. 3605-3619 ◽  
Author(s):  
C. Willis ◽  
R. A. Back
Keyword(s):  
Gas Phase ◽  
Room Temperature ◽  
Chemical Properties ◽  
Phase Decomposition ◽  
Important Intermediate ◽  
Long Lifetime ◽  
Physical And Chemical ◽  
Text Formation ◽  
Kinetics Of

Preparation of di-imide by passing hydrazine vapor through a microwave discharge yields mixtures with NH3 containing typically about 15% N2H2, estimated from the gases evolved on decomposition. The behavior of the mixture (which melts at −65 °C) on warming from −196 to −30 °C suggests a strong interaction between the components. Measurements of magnetic susceptibility and e.p.r. experiments showed that N2H2 is not strongly paramagnetic, which with other observations points to a singlet rather than a triplet ground-state.Di-imide can be vaporized efficiently, together with NH3, by rapid warming, and the vapor is surprisingly long-lived, with a typical half-life of several minutes at room temperature. The near-u.v. (3200–4400 Å) absorption spectrum of the vapor was photographed; it shows well-defined but diffuse bands, with εmax = 6(± 3) at 3450 Å.Di-imide decomposes at room temperature in two ways:[Formula: see text][Formula: see text]Formation of NH3 was not observed but cannot be ruled out. The decomposition of the vapor is complicated by a sizeable and variable decomposition that occurs rapidly during the vaporization. The stoichiometry of this and the vapor-phase decomposition depends on total pressure and di-imide concentration. The kinetics of the decomposition of the vapor were studied from 22 to 200 °C by following the disappearance of N2H2 by absorption of light at 3450 Å, or the formation of N2H4 by absorption at 2400 Å, and by mass spectrometry. The kinetics are complex and can be either first- or second-order, or mixed, depending on surface conditions. The effect of olefin additives on the decomposition was studied, and is also complex.Mechanisms for the decomposition are discussed, including the possible role of trans-cis isomerization. The relatively long lifetime found for di-imide in the gas phase suggests that it may be an important intermediate in many reactions of hydronitrogen systems.

Catalysis by hydrogen halides in the gas phase. XXIII. 1,1-Dimethoxyethane and hydrogen bromide

1971 ◽  
Vol 24 (5) ◽  
pp. 961 ◽  
Author(s):  
VR Stimson
Keyword(s):  
Gas Phase ◽  
Vinyl Ether ◽  
Arrhenius Equation ◽  
Hydrogen Bromide ◽  
Phase Decomposition ◽  
Hydrogen Halides ◽  
Methyl Vinyl ◽  
First Order ◽  
Methyl Vinyl Ether

Hydrogen bromide catalyses the gas-phase decomposition of 1,1- dimethoxy-ethane at 233-322� into methyl vinyl ether and methanol. The reaction, first-order in each reactant, is believed to be homogeneous and molecular. ��� The Arrhenius equation ������ �����������k2 = 1.3x1013exp(-22160/RT) s-1 cm3 mol-1 is followed. This decomposition is much faster than the analogous reactions of alcohols and ethers. The catalyst is effective when present in only 1% proportion.

Photosensitization by Cd(3P0,1) atoms. III. Gas phase decomposition of cyclopentane

1976 ◽  
Vol 54 (1) ◽  
pp. 77-84 ◽  
Author(s):  
Bansi L. Kalra ◽  
Arthur R. Knight
Keyword(s):  
Gas Phase ◽  
Vapor Phase ◽  
Product Formation ◽  
Time Dependent ◽  
Primary Process ◽  
Phase Decomposition ◽  
Unimolecular Decomposition ◽  
Hydrogen Atoms ◽  
Volatile Products ◽  
Radical Decomposition

The triplet cadmium photosensitized decomposition of cyclopentane in the vapor phase has been studied at 355 °C and has been shown to give rise to cyclopentyl radicals and hydrogen atoms with close to unit efficiency in the primary process. Subsequent reactions of these species, including an important contribution from unimolecular decomposition of cyclopentyl radicals, yield the observed volatile products, hydrogen, methane, ethylene, ethane, propylene, and cyclopentene. As a result of significant olefin scavenging of H-atoms product yields are strongly time dependent. The system has been shown to be unaffected by addends. The temperature dependence of the rate of product formation is consistent with the known energetics of cyclopentyl radical decomposition.

New insight into the role of gas phase reactions in the partial oxidation of butane

2003 ◽  
Vol 81 (2) ◽  
pp. 205-213 ◽  
Author(s):  
Sergio Marengo ◽  
Paola Comotti ◽  
Giovanni Galli
Keyword(s):  
Gas Phase ◽  
Partial Oxidation ◽  
Gas Phase Reactions ◽  
Insight Into

Hydrogen bonded supramolecular structures: a further insight into the diamine-diol recognition and self-assembly

2000 ◽  
Vol 78 (6) ◽  
pp. 723-731 ◽  
Author(s):  
Stefano Roelens ◽  
Paolo Dapporto ◽  
Paola Paoli
Keyword(s):  
Molecular Recognition ◽  
Gas Phase ◽  
Self Assembly ◽  
Supramolecular Assembly ◽  
Supramolecular Structures ◽  
Unique Role ◽  
X Ray ◽  
Molecular Code ◽  
Insight Into

A new H-bonded supramolecular assembly of the diamine-diol family has been obtained from (1R,2R)-1,2-diaminocyclohexane (DAC) and (S)-1-phenyl-1,2-ethanediol (PED). The structure was characterized by single-crystal X-ray analysis and showed the typical architecture of DAC based assemblies, consisting of a three-stranded helicate coiling around a H-bonded core, with a predictable helicity sense determined by the configuration of DAC. The new assembly, while reconfirming the unique role of DAC as a powerful assembler of supramolecular structures, demonstrated that the C2 symmetry of diol partners employed so far is not essential for assembling helicates, although chirality is. In the case of the adduct between (1R,2R)-1,2-diaminocyclohexane and (2R,3R)-2,3-butanediol, molecular recognition and self-assembly have been shown to take place even in the absence of solvent, in the gas phase, where long crystals were formed by spontaneous organized aggregation of diamine-diol units. A thorough analysis of the results from the present and previous investigations has lead to a deeper understanding of the key features of the diamine-diol molecular code and of the requirements for recognition and assembly.Key words: supramolecular, hydrogen bonding, molecular recognition, self-assembly, diamines, diols.

A novel variation of GDF3 in Chinese Han children with a broad phenotypic spectrum of non-syndromic CHDs

2014 ◽  
Vol 25 (7) ◽  
pp. 1263-1267 ◽  
Author(s):  
Jianmin Xiao ◽  
Guanyang Kang ◽  
Jing Wang ◽  
Tengyan Li ◽  
Jiuhao Chen ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Septal Defect ◽  
System Development ◽  
Reaction Products ◽  
Chain Reaction ◽  
Chinese Han ◽  
Polymerase Chain ◽  
Embryonic Morphogenesis ◽  
Insight Into

AbstractBackgroundThe GDF3 gene plays a fundamental role in embryonic morphogenesis. Recent studies have indicated that GDF3 plays a previously unrecognised role in cardiovascular system development. Non-syndromic CHDs might be a clinically isolated manifestation of GDF3 mutations. The purpose of the present study was to identify potential pathological mutations in the GDF3 gene in Chinese children with non-syndromic CHDs, and to gain insight into the aetiology of non-syndromic CHDs.MethodsA total of 200 non-syndromic CHDs patients and 202 normal control patients were sampled. There were two exons of the human GDF3 gene amplified using polymerase chain reaction. The polymerase chain reaction products were purified and directly sequenced.ResultsOne missense mutation (c.C635T, p.Ser212 Leu, phenotype: isolated muscular ventricular septal defect) was found that has not been reported previously.ConclusionsTo the best of our knowledge, this is the first study to investigate the role of the GDF3 gene in non-syndromic CHDs. Our results expand the spectrum of mutations associated with CHDs and first suggest the potentially disease-related GDF3 gene variant in the pathogenesis of CHDs.

The Role of Gas Phase Decomposition in the ALE Growth of III–V Compounds

1991 ◽  
Vol 222 ◽  
Author(s):  
K. G. Reid ◽  
H. M. Urdianyk ◽  
N. A. El-Masry ◽  
S. M. Bedair
Keyword(s):  
Boundary Layer ◽  
High Temperature ◽  
Gas Phase ◽  
Exposure Time ◽  
Growth Temperature ◽  
Phase Decomposition ◽  
Temperature Growth ◽  
Mocvd Reactor ◽  
Maximum Exposure

ABSTRACTThe effects of the growth temperature and exposure time to TMGa for ALE of gallium arsenide was studied using TMGa and AsH3 in a modified, vertical, atmospheric, MOCVD reactor with a rotating susceptor. It was found that the temperature range for ALE growth could -be extended from 450°C to 700°C by adjustment of the exposure time to TMGa. The maximum exposure time to TMGa was found to decrease as growth temperature increased with high temperature growth limited to exposures of only fractions of a second. Beyond a critical exposure time to TMGa, gallium droplets form on the surface. It is known that premature decomposition of TMGa in the heated gaseous boundary layer causes the formation of the gallium droplets and the consequent loss of ALE growth.

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