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. 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. 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. 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. 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.

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. 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. 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.

The gas-phase reaction of methyl acetate and hydrogen bromide

1971 ◽  
Vol 24 (9) ◽  
pp. 1823
Author(s):  
NJ Daly ◽  
MF Gilligan
Keyword(s):  
Acetic Acid ◽  
Gas Phase ◽  
Kinetic Data ◽  
Methyl Acetate ◽  
Hydrogen Bromide ◽  
Mesityl Oxide ◽  
Phase Reaction ◽  
Gas Phase Reaction ◽  
First Order ◽  
Order Form

In the gas phase methyl acetate reacts with hydrogen bromide over the range 419-497� to give methyl bromide, carbon monoxide, and methanol. Rate constants first order in both ester and hydrogen bromide are calculated from initial slopes, and are described by the equation �������������������� k2 = 1012.29exp(-32312/RT) ml mol-1 s-1 Kinetic data depart from this second-order form at early stages of the reaction. The addition of methanol can reduce the value of k2 to zero. A mechanism involving the reversible step : ������������������������ CH3COOCH3+HBr ↔ CH3OH+A* is proposed. The intermediate reacts with isobutene to form mesityl oxide, and is considered identical with that formed in the reaction of acetic acid with hydrogen bromide.

ChemInform Abstract: CATALYSIS BY HYDROGEN HALIDES IN THE GAS PHASE PART 26, ISOPROPYLAMINE AND HYDROGEN BROMIDE

1974 ◽  
Vol 5 (46) ◽  
Author(s):  
ALLAN MACCOLL ◽  
SURGIT S. NAGRA
Keyword(s):  
Gas Phase ◽  
Hydrogen Bromide ◽  
Hydrogen Halides

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.

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