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. 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. 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.

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. XVII. Isobutyric acid and hydrogen bromide

1968 ◽  
Vol 21 (3) ◽  
pp. 725 ◽  
Author(s):  
JTD Cross ◽  
VR Stimson
Keyword(s):  
Carbon Monoxide ◽  
Gas Phase ◽  
Rate Constants ◽  
Hydrogen Bromide ◽  
Isobutyric Acid ◽  
Kcal Mole ◽  
Hydrogen Halides ◽  
Arrhenius Parameters ◽  
First Order ◽  
Added Water

Hydrogen bromide catalyses the decomposition of isobutyric acid into propene, carbon monoxide, and water at 369-454�. Hydrogen bromide is not lost. Individual runs follow the first-order rate law, and the rate constants are proportional to the hydrogen bromide pressure. The Arrhenius parameters are: E = 33.17 kcal mole-1 and A = 1012.87 sec-1 ml mole-1, and the reaction is homogeneous and molecular. Added water or methanol retards the reaction.

Catalysis by hydrogen halides in the gas phase. XIV. Methyl trimethylacetate and hydrogen bromide and the effects of added alcohols

1968 ◽  
Vol 21 (3) ◽  
pp. 687 ◽  
Author(s):  
JTD Cross ◽  
VR Stimson
Keyword(s):  
Carbon Monoxide ◽  
Methyl Ester ◽  
Gas Phase ◽  
Hydrogen Chloride ◽  
Hydrogen Bromide ◽  
Hydrogen Halides ◽  
Kinetic Form

Hydrogen bromide and hydrogen chloride catalyse the decomposition of methyl trimethylacetate into isobutene, carbon monoxide, and methanol at 370-442� and 450-48O�, respectively. The kinetic form, which is basically 1 : 1, is severely modified by the effect of methanol either produced in the reaction or added initially. Water or alcohols react with an intermediate in the catalysed decomposition of trimethylacetic acid or its methyl ester in esterification-like reactions; some of the resultant esters subsequently decompose to olefin and acid.

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.

The thermal decompositions of 2-methyl-2-phenoxypropane

1981 ◽  
Vol 34 (2) ◽  
pp. 343 ◽  
Author(s):  
NJ Daly ◽  
SA Robertson ◽  
LP Steele
Keyword(s):  
Gas Phase ◽  
Reaction Mechanisms ◽  
Arrhenius Equation ◽  
Chain Process ◽  
Quadrupole Mass ◽  
Radical Chain ◽  
Thermal Reactions ◽  
First Order ◽  
Radical Chain Process ◽  
Good Agreement

The thermal reactions of 2-methyl-2-phenoxypropane have been studied in gas phase over the range 600-670 K by quadrupole mass spectrometry and pressure studies. The reaction is shown to be a homogeneous first-order elimination of phenol and 2-methylpropene which is described by the Arrhenius equation k = 1014.10�0.12exp[(-210.46�1.36)/RT] s-1 Possible reaction mechanisms are considered and the reaction is found to be a unimolecular elimination rather than a radical chain process initiated by homolysis to phenoxy and 1,1-dimethylethyl radicals. Evidence for the rearrangement to 4-t-butylphenol previously proposed has been carefully sought and it is concluded that the process does not occur in the gas phase. The A-factor observed for the reaction is in good agreement with that calculated for the four-centred transition state proposed for elimination of 2-methylpropene from alkoxypropanes.

The gas-phase reaction of acetic acid with hydrogen bromide

1969 ◽  
Vol 22 (4) ◽  
pp. 713 ◽  
Author(s):  
NJ Daly ◽  
MF Gilligan
Keyword(s):  
Carbon Monoxide ◽  
Acetic Acid ◽  
Gas Phase ◽  
Rate Constant ◽  
Methyl Bromide ◽  
Hydrogen Bromide ◽  
Phase Reaction ◽  
Gas Phase Reaction ◽  
First Order ◽  
The Family

In the gas phase, acetic acid reacts with hydrogen bromide in the temperature range 412-492� to give methyl bromide, carbon monoxide, and water. The reaction is first order in each reagent, and the variation of rate constant with temperature is described by the equation �� ����������������� k2 = 1011.67exp(-30400/RT) ml mole-1 sec-1 Possible transition states for the reaction are examined. A mechanism involving an intermediate of the type CH3CO+Br- is possible if the reaction is of the family represented by the hydrogen bromide catalysed decompositions of trimethylacetic, isobutyric, and propionic acids.

Catalysis by hydrogen halides in the gas phase. XIII. Isopropanol and hydrogen iodide

1967 ◽  
Vol 20 (6) ◽  
pp. 1143 ◽  
Author(s):  
RL Failes ◽  
VR Stimson
Keyword(s):  
Gas Phase ◽  
Hydrogen Chloride ◽  
Rate Constants ◽  
Arrhenius Equation ◽  
Hydrogen Bromide ◽  
Hydrogen Iodide ◽  
Initial Reaction ◽  
Hydrogen Halides ◽  
The Individual

Hydrogen iodide catalyses the decomposition of isopropanol into propene and water at 356 to 457�, viz. �������������������������� i-C3H7OH+HI → C3H6+H2O+HI This is followed by the faster reactions �������������������������� C3H6+HI → i-C3H7I ����� ��������������������i-C3H7I+HI → C3H8+I2������������������������ i-C3H7OH+I2 → (CH3)2CO+2HI The rates of the initial reaction fit the Arrhenius equation ����������������� k2 = 1012.24 exp(-31900/RT) sec-1 ml mole-1 and it is believed to be homogeneous and molecular. It is faster than the corresponding reactions with hydrogen chloride and hydrogen bromide in the ratios 100 : 1 and 5 : 1, respectively. For the overall reaction the amounts of the products formed to 70% reaction, computed with the use of rate constants of the individual reactions, agree well with the amounts found by analysis.

The thermal decomposition of trimethylacetyl bromide

1970 ◽  
Vol 23 (3) ◽  
pp. 525 ◽  
Author(s):  
BS Lennon ◽  
VR Stimson
Keyword(s):  
Thermal Decomposition ◽  
Carbon Monoxide ◽  
Hydrogen Bromide ◽  
Transition States ◽  
Volume Ratio ◽  
Reaction Vessel ◽  
Chain Mechanism ◽  
Radical Chain ◽  
First Order ◽  
Polar Transition

Trimethylacetyl bromide decomposes at 298-364� into isobutene, carbon monoxide, and hydrogen bromide in a first-order manner with rate given by k1 = 138 x 1014exp(-48920/RT) sec-1 The rate is unaffected by addition of the products or of inhibitors, or by increase of the surface/volume ratio of the reaction vessel. The likely radical chain mechanism is considered and rejected. The reaction is believed to be a molecular one, and possible cyclic and polar transition states are discussed.

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