Catalysed gas phase decompositions. XXV. 2,2-Dimethoxypropane and acetic acid

1973 ◽  
Vol 26 (4) ◽  
pp. 761 ◽  
Author(s):  
DA Kairaitis ◽  
VR Stimson ◽  
JW Tilley
Keyword(s):  
Acetic Acid ◽  
Gas Phase ◽  
Arrhenius Equation ◽  
Hydrogen Halide ◽  
First Order ◽  
Temperature Range

Acetic acid catalyses the decomposition of 2,2-dimethoxypropane into methyl isopropenyl ether and methanol in the temperature range 314- 400�. The reaction is first order in the pressure of each reactant, and the variation of rate with temperature is given by the Arrhenius equation: ������������ k2 = 1012.90�0.15exp(-30830�420/1.987T) s-1 ml mol-1 The reaction is believed to be homogeneous and molecular. This is the first example of this series where the catalyst has been other than a hydrogen halide.

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.

Acetoxylation by aryliodoso acetates. II. Kinetics of the reaction of phenyliodoso acetate with aceto-p-toluidide

1958 ◽  
Vol 11 (1) ◽  
pp. 34
Author(s):  
WD Johnson ◽  
NV Riggs
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Transition State ◽  
Arrhenius Equation ◽  
First Order ◽  
Temperature Range ◽  
Polar Transition ◽  
Kinetics Of

The reaction of phenyliodoso acetate and aceto-p-toluidide in acetic acid is first order in each reactant and measured rates fit the Arrhenius equation in the temperature range 15-45 �C. Addition of water to the solvent markedly accelerates the reaction, whereas addition of benzene lowers the rate and acetic anhydride has little effect. A polar transition state is indicated.

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 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 thermal decompositions of carbamates. IV. The reactions of isopropyl N,N-dimethylcarbamate and t-butyl N,N-dimethylcarbamate

1980 ◽  
Vol 33 (3) ◽  
pp. 481 ◽  
Author(s):  
NJ Daly ◽  
F Ziolkowski
Keyword(s):  
Carbon Dioxide ◽  
Gas Phase ◽  
Rate Equations ◽  
First Order ◽  
Temperature Range ◽  
Ammonium Carbamate

The thermal decompositions of isopropyl N,N-dimethylcarbamate and t- butyl N,N-dimethylcarbamate are shown to occur over the temperature range 485-602 K through the reactions Me2NCO2Pri → Me2NH+CO2+MeCH=CH2 Me2NCO2But → Me2NH+CO2+Me2C=CH2 which are described as first-order unimolecular processes for which the rate equations are isopropyl k = 1013.04exp(-181209/8.314T) s-1 �t-butyl k = 1012.87exp(-157904/8.314T) s-1 For both carbamates these rate equations describe the rates of formation of the amine and the appropriate alkene but apparently overestimate the rate of carbon dioxide formation. The discrepancy in the carbon dioxide data is explained in terms of the formation of an amine-carbon dioxide adduct during the condensation stage of the analyses. The adduct is described as an ammonium carbamate which undergoes hydrolysis in solution to free the original amine. The existence of transesterification in the gas phase is ruled out.

The thermal isomerisation of allyl isocyanide

1979 ◽  
Vol 57 (18) ◽  
pp. 2482-2483 ◽  
Author(s):  
Marsha T. J. Glionna ◽  
Huw O. Pritchard
Keyword(s):  
Activation Energy ◽  
High Pressure ◽  
Gas Phase ◽  
Frequency Factor ◽  
First Order ◽  
Temperature Range

The thermal isomerisation of allyl isocyanide to allyl cyanide has been studied in the gas phase over the temperature range 130–200 °C. The reaction is homogeneous and first order, and at high pressure (20 Torr) has an activation energy of 40.8 ± 0.6 (2sdm) kcal mol−1; the corresponding range of frequency factor is 1014.77±0.30 s−1.

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.

Thermal decomposition of citraconic anhydride

1971 ◽  
Vol 24 (4) ◽  
pp. 771 ◽  
Author(s):  
NJ Daly ◽  
F Ziolkowski
Keyword(s):  
Carbon Dioxide ◽  
Thermal Decomposition ◽  
Gas Phase ◽  
Rate Constant ◽  
Arrhenius Equation ◽  
Volume Ratio ◽  
Reaction Vessel ◽  
First Order ◽  
First Order Kinetics ◽  
Citraconic Anhydride

Citraconic anhydride decomposes in the gas phase over the range 440- 490� to give carbon dioxide, carbon monoxide, and propyne which undergoes some polymerization to trimethylbenzenes. The decomposition obeys first-order kinetics, and the Arrhenius equation ������������������� k1 = 1015.64 exp(-64233�500/RT) (s-1) describes the variation of rate constant with temperature. The rate constant is unaffected by the addition of isobutene or by increase in the surface/volume ratio of the reaction vessel. The reaction appears to be unimolecular and if a diradical intermediate is involved it may not be fully formed in the transition state.

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