Catalysis by hydrogen halides in the gas phase. IX. Tertiary butyl ether and hydrogen bromide

1966 ◽  
Vol 19 (1) ◽  
pp. 75 ◽  
Author(s):  
VR Stimson ◽  
EJ Watson
Keyword(s):  
Gas Phase ◽  
Hydrogen Bromide ◽  
Zero Order ◽  
Chain Reaction ◽  
Butyl Ether ◽  
Radical Chain ◽  
Hydrogen Halides ◽  
Tertiary Butyl ◽  
First Order ◽  
Radical Chain Reaction

The hydrogen bromide catalysed decomposition of t-butyl ethyl ether takes place at 263-337�. Two major reactions occur, one producing isobutene by kinetics first order in each reactant, and the other isobutane by kinetics first order in the ether and zero order in hydrogen bromide. The latter is extensively inhibited by cyclohexene and is a radical chain reaction; the former is not inhibited and is presumably molecular, and on this basis its properties form a smooth sequence with those of other similar hydrogen halide catalysed decompositions.

Catalysis by hydrogen halides in the gas phase. XVIII. Methyl formate and hydrogen bromide

1968 ◽  
Vol 21 (7) ◽  
pp. 1711
Author(s):  
DA Kairaitis ◽  
VR Stimson
Keyword(s):  
Carbon Monoxide ◽  
Gas Phase ◽  
Decomposition Product ◽  
Methyl Formate ◽  
Arrhenius Equation ◽  
Hydrogen Bromide ◽  
Radical Chain ◽  
Hydrogen Halides ◽  
Chain Decomposition ◽  
First Order

Hydrogen bromide catalyses the decomposition of methyl formate into carbon monoxide and methanol at 390-460�. The radical chain decomposition product, methane, is formed in only a small amount that is further reduced by the addition of inhibitor. The reaction is homogeneous and molecular, is first order in each reactant, and follows the Arrhenius equation: k2 = 1012.50exp(-32200/RT)sec-1 ml mole-1 It is not reversed by added methanol.

Catalysis by hydrogen halides in the gas phase. XV. Trimethylacetic acid, isopropanol, and hydrogen bromide

1968 ◽  
Vol 21 (3) ◽  
pp. 701 ◽  
Author(s):  
JTD Cross ◽  
VR Stimson
Keyword(s):  
Acetic Acid ◽  
Gas Phase ◽  
High Pressures ◽  
Hydrogen Bromide ◽  
Zero Order ◽  
Hydrogen Halides ◽  
First Order ◽  
Low Alcohol

Isopropanol decomposes to propene and water in the presence of trimethyl-acetic acid and hydrogen bromide at 407� via isopropyl trimethylacetate. This takes place by isopropanol reacting with an intermediate in the hydrogen bromide catalysed decomposition of trimethylacetic acid. The reaction is first order in each of the acids and first order in the alcohol at low alcohol pressures and zero order at high pressures.

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.

Catalysis by hydrogen halides in the gas phase. XI. Tertiary butyl ethyl ether and hydrogen chloride

1966 ◽  
Vol 19 (3) ◽  
pp. 401 ◽  
Author(s):  
VR Stimson ◽  
EJ Watson
Keyword(s):  
Gas Phase ◽  
Hydrogen Chloride ◽  
Ethyl Ether ◽  
Arrhenius Equation ◽  
Hydrogen Halide ◽  
Hydrogen Halides ◽  
Tertiary Butyl ◽  
First Order ◽  
Mechanism Of The Reaction ◽  
Kinetic Form

Hydrogen chloride catalyses the decomposition of t-butyl ethyl ether at 320-428�. Isobutene is quantitatively the product and the kinetic form is first order in the ether and in hydrogen chloride. The Arrhenius equation:��������� k, = 1012'16exp( -30,60O/RT) (sec-l ml mole-=) is followed. The mechanism of the reaction seems similar to those of other hydrogen halide catalysed decompositions of ethers and alcohols.

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.

scholarly journals Sulfur isotope fractionation during oxidation of sulfur dioxide: gas-phase oxidation by OH radicals and aqueous oxidation by H<sub>2</sub>O<sub>2</sub>, O<sub>3</sub> and iron catalysis

2011 ◽  
Vol 11 (8) ◽  
pp. 23959-24002 ◽  
Author(s):  
E. Harris ◽  
B. Sinha ◽  
P. Hoppe ◽  
J. N. Crowley ◽  
S. Ono ◽  
...  
Keyword(s):  
Gas Phase ◽  
Sulfur Isotope ◽  
Isotopic Fractionation ◽  
Oh Radicals ◽  
Chain Reaction ◽  
Radical Chain ◽  
Fractionation Factor ◽  
Gas Phase Oxidation ◽  
Aqueous Oxidation ◽  
Radical Chain Reaction

Abstract. The oxidation of SO2 to sulfate is a key reaction in determining the role of sulfate in the environment through its effect on aerosol size distribution and composition. Sulfur isotope analysis has been used to investigate sources and chemistry of sulfur dioxide and sulfate in the atmosphere, however interpretation of measured sulfur isotope ratios is challenging due to a lack of reliable information on the isotopic fractionation involved in major transformation pathways. This paper presents measurements of the fractionation factors for the major atmospheric oxidation reactions for SO2: Gas-phase oxidation by OH radicals, and aqueous oxidation by H2O2, O3 and a radical chain reaction initiated by iron. The measured fractionation factor for 34S/32S during the gas-phase reaction is αOH = (1.0089±0.0007) − ((4±5)×10−5) T(°C). The measured fractionation factor for 34S/32S during aqueous oxidation by H2O2 or O3 is αaq=(1.0167±0.0019) − ((8.7±3.5) ×10−5) T(°C). The observed fractionation during oxidation by H2O2 and O3 appeared to be controlled primarily by protonation and acid-base equilbria of S(IV) in solution, and there was no significant difference between the fractionation produced by the two oxidants within the experimental error. The isotopic fractionation factor from a radical chain reaction in solution catalysed by iron is αFe = (0.989±0.0043) at 19 °C for 34S/32S. Fractionation was mass-dependent with regards to 33S for all the reactions investigated. The radical chain reaction mechanism was the only measured reaction that had a faster rate for the light isotopes, and will be particularly useful to determine the importance of the transition-metal catalysed oxidation pathway.

Catalysis by hydrogen halides in the gas phase. XX. Propionic acid and hydrogen bromide

1970 ◽  
Vol 23 (6) ◽  
pp. 1149
Author(s):  
DA Kairaitis ◽  
VR Stimson
Keyword(s):  
Gas Phase ◽  
Propionic Acid ◽  
Hydrogen Bromide ◽  
Initial Pressure ◽  
Pressure Change ◽  
Ethyl Bromide ◽  
Initial Reaction ◽  
Hydrogen Halides ◽  
First Order ◽  
Kinetic Form

Hydrogen bromide catalyses the decomposition of propionic acid at 405-468�. The initial products are ethyl bromide, carbon monoxide, and water; however, ethyl bromide decomposes into ethylene and hydrogen bromide at rates comparable with those of the initial reaction. The kinetic form of an individual run is therefore not simple, and initial pressure change has been used to measure the rate. The reaction,is first order in each reactant, and the variation of rate with temperature is given by K2 = 1.36 x 1012exp(-30850/RT) s-1 ml mol-1 Comparison with the hydrogen bromide catalysed decarbonylations of other acids and esters has been made. Isobutene added to the reaction affects the kinetic form of individual runs slightly and mainly through its effect on the decomposition of ethyl bromide.

Catalysis by hydrogen halides in the gas phase. X. Tertiary butyl methyl ether and hydrogen chloride

1966 ◽  
Vol 19 (3) ◽  
pp. 393 ◽  
Author(s):  
VR Stimson ◽  
EJ Watson
Keyword(s):  
Gas Phase ◽  
Surface Area ◽  
Hydrogen Chloride ◽  
Methyl Ether ◽  
Rate Equation ◽  
Hydrogen Halides ◽  
Tertiary Butyl ◽  
First Order ◽  
Tertiary Butyl Methyl Ether ◽  
Butyl Methyl Ether

The decomposition of t-butyl methyl ether catalysed by hydrogen chloride takes place at 337-428�. It is first order in each reactant and the rate is not affected by increase in surface area or inhibitor. The rate equation is: K2 = 1012.46exp(-32100/RT) (sec-l ml mole-l) The reaction is believed to be molecular and its properties are in accord with those of other such catalysed decompositions.

scholarly journals Sulfur isotope fractionation during oxidation of sulfur dioxide: gas-phase oxidation by OH radicals and aqueous oxidation by H<sub>2</sub>O<sub>2</sub>, O<sub>3</sub> and iron catalysis

2012 ◽  
Vol 12 (1) ◽  
pp. 407-423 ◽  
Author(s):  
E. Harris ◽  
B. Sinha ◽  
P. Hoppe ◽  
J. N. Crowley ◽  
S. Ono ◽  
...  
Keyword(s):  
Gas Phase ◽  
Sulfur Isotope ◽  
Isotopic Fractionation ◽  
Oh Radicals ◽  
Chain Reaction ◽  
Radical Chain ◽  
Fractionation Factor ◽  
Gas Phase Oxidation ◽  
Aqueous Oxidation ◽  
Radical Chain Reaction

Abstract. The oxidation of SO2 to sulfate is a key reaction in determining the role of sulfate in the environment through its effect on aerosol size distribution and composition. Sulfur isotope analysis has been used to investigate sources and chemical processes of sulfur dioxide and sulfate in the atmosphere, however interpretation of measured sulfur isotope ratios is challenging due to a lack of reliable information on the isotopic fractionation involved in major transformation pathways. This paper presents laboratory measurements of the fractionation factors for the major atmospheric oxidation reactions for SO2: Gas-phase oxidation by OH radicals, and aqueous oxidation by H2O2, O3 and a radical chain reaction initiated by iron. The measured fractionation factor for 34S/32S during the gas-phase reaction is αOH = (1.0089±0.0007)−((4±5)×10−5) T(°C). The measured fractionation factor for 34S/32S during aqueous oxidation by H2O2 or O3 is αaq = (1.0167±0.0019)−((8.7±3.5) ×10−5)T(°C). The observed fractionation during oxidation by H2O2 and O3 appeared to be controlled primarily by protonation and acid-base equilibria of S(IV) in solution, which is the reason that there is no significant difference between the fractionation produced by the two oxidants within the experimental error. The isotopic fractionation factor from a radical chain reaction in solution catalysed by iron is αFe = (0.9894±0.0043) at 19 °C for 34S/32S. Fractionation was mass-dependent with regards to 33S/32S for all the reactions investigated. The radical chain reaction mechanism was the only measured reaction that had a faster rate for the light isotopes. The results presented in this study will be particularly useful to determine the importance of the transition metal-catalysed oxidation pathway compared to other oxidation pathways, but other main oxidation pathways can not be distinguished based on stable sulfur isotope measurements alone.

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