Kinetic study of the thermal isomerization of fulvene

1981 ◽  
Vol 34 (2) ◽  
pp. 449 ◽  
Author(s):  
BJ Gaynor ◽  
RG Gilbert ◽  
KD King ◽  
PJ Harman
Keyword(s):  
High Pressure ◽  
Reaction Mechanism ◽  
Kinetic Study ◽  
Low Pressure ◽  
Thermal Isomerization ◽  
Marcus Theory ◽  
Rate Coefficients ◽  
Arrhenius Parameters ◽  
Temperature Range ◽  
Concerted Reaction

The thermal unimolecular isomerization of fulvene to benzene was studied by the technique of very low-pressure pyrolysis. The observed fall-off regime rate coefficients (obtained over the temperature range of c. 1050-1150 K) were fitted by using RRKM (Rice-Ramsperger-Kassel-Marcus) theory (assuming a concerted reaction mechanism) to give high-pressure Arrhenius parameters in the range E∞ = 268-285 kJ mol-1, log(A/s-1) = 13-14.

The reaction of methyl radicals with neopentane in flow photolysis at 607–823 K

1984 ◽  
Vol 62 (6) ◽  
pp. 1203-1206 ◽  
Author(s):  
Hiroshi Furue ◽  
Kim C. Manthorne ◽  
Philip D. Pacey
Keyword(s):  
Heat Capacity ◽  
High Pressure ◽  
Arrhenius Plot ◽  
Flow System ◽  
Rate Coefficients ◽  
Methyl Radicals ◽  
Large Excess ◽  
Arrhenius Parameters ◽  
Temperature Range ◽  
Pressure Limit

Acetone was photolyzed in the presence of a large excess of neopentane in a flow system at total pressures between 7 and 150 Torr and at 607–823 K. For reactions[Formula: see text]and[Formula: see text]the quotient of rate coefficients, k12/k2, was calculated from CH4 and C2H6 yields and was extrapolated to the high pressure limit, k12/k2,x. Taking k2,x as 2.2 × 1010 L mol−1 s1, Arrhenius parameters for reaction [1] were found to be: log10A (L mol−1 s−1) = 10.0 ± 0.1, EA = 62( ± 2) kJ mol−1. In combination with data from the literature for the temperature range 365–953 K, the Arrhenius plot for k1/k2,x1/2 was strongly curved, with a heat capacity of activation of 71 ± 4 J K−1 mol−1.

THE THERMAL DECOMPOSITION OF ETHANE: PART I. INITIATION AND TERMINATION STEPS

1966 ◽  
Vol 44 (4) ◽  
pp. 505-514 ◽  
Author(s):  
M C. Lin ◽  
M. H. Back
Keyword(s):  
Thermal Decomposition ◽  
High Pressure ◽  
Rate Coefficients ◽  
First Order ◽  
Temperature Range ◽  
Order Rate ◽  
Ethyl Radical ◽  
Initiation Reaction ◽  
Ethyl Radicals

The rates of production of methane and butane in the pyrolysis of ethane have been measured over the temperature range 550–620 °C and at pressures of 40–600 mm. At high pressure the rates of formation of both products were first order in ethane, but below 200 mm the first-order rate coefficients decreased. The ratio of methane to butane was consistent with the interpretation that methane is a measure of the initiation reaction and that the combination and disproportionation of ethyl radicals is the main termination step. The order of the decomposition of the ethyl radical with respect to ethane varied between 0.38 and 0.59. The results are discussed in terms of the mechanism of the overall process.

The thermal isomerization of 1. 2-dimethyl cyclo propane II. Structural isomerization

1961 ◽  
Vol 260 (1302) ◽  
pp. 424-432 ◽  
Keyword(s):  
Transition State ◽  
Thermal Isomerization ◽  
Reaction Vessel ◽  
Rate Equations ◽  
Arrhenius Parameters ◽  
Temperature Range ◽  
Structural Isomerization ◽  
Electronic Integration ◽  
Ring Transition State

This isomerization has been investigated between 434 and 475 °C. In this temperature range, in an ‘aged’ reaction vessel, the structural isomerization from either cis or trans 1. 2-dimethyl cyclo propane occurs as a unimolecular transformation which is slower than the reversible cis-trans isomerization. The products of the reaction are 2-methylbut-1-ene, 2-methylbut-2-ene and cis and trans pent-2-ene. The rates of formation of these compounds have been measured and the Arrhenius parameters evaluated. The rate equations for the formation of 2-methylbut-1-ene and 2-methylbut-2-ene are k ∞ = 10 13.93 exp(-61900/ RT ) S -1 and 10 14.08 exp (-62300/ RT ) S -1 respectively and are the same for their production from either the cis or the trans dimethyl cyclo propane. The pent-2-enes are formed more rapidly from cis 1. 2-dimethy cyclo propane than from the trans compound. From cis 1.2-dimethyl cyclo propane cis and trans pent-2-ene are formed at rates given by the equations k ∞ = 10 13.92 exp (-61400/ RT )s -1 and 10 13.96 exp (-61200/ RT )s -1 , respectively. From trans 1.2-dimethyl cyclo propane the rate equations are k ∞ = 10 14.40 exp (-63600/ RT )s -1 and 10 14.30 exp (-62900/ RT )s -1 . The possible mechanisms for both the geometrical and structural isomerizations have been discussed and it has been concluded than an ‘expanded ring’ transition state gives a satis­factory explanation of the results obtained. It is also suggested that this strengthens the case for a similar mechanism in the case of the isomerization of cyclo propane. Gas chromato­graphy, by means of a katharometer detector with electronic integration, has been used throughout and has been developed to give a precision of ±0.5% in the analysis of the reaction mixtures.

The radical stabilization energy due to an a-chlorine atom from the kinetics of the thermal isomerization of 1-Chlorobicyclo[2,2,0]hexane in the gas and liquid phase

1975 ◽  
Vol 28 (9) ◽  
pp. 2079 ◽  
Author(s):  
RK Solly ◽  
EN Cain
Keyword(s):  
Liquid Phase ◽  
Least Squares ◽  
Gas Phase ◽  
Chlorine Atom ◽  
Excellent Agreement ◽  
Thermal Isomerization ◽  
Stabilization Energy ◽  
Arrhenius Parameters ◽  
Temperature Range ◽  
Kinetics Of

The rate of isomerization of 1-chlorobicyclo[2,2,0]hexane to 2- chlorohexa-1,5-diene, both in the gas phage and in solution, has been measured over the temperature range 409-497 K. The Arrhenius parameters derived from these rates are represented by the equations ����������������������������� log(kg/s-1)=(13.49�0.08)-(148.2�0.6/θ ����������������������������� log(ka/s-1)=(13.21�0.12)-(144.44�0.50)/θ� and����������������������������� log(kb/s-1)=(13.25�0.44)-(144.8�1.6)/θ where the subscripts g, a and b refer to the gas phase, tetrachloroethylene as solvent and o-dichloro-benzene as solvent respectively, θ = 19.15 kJ mol-1 and the errors are least-squares deviations. A radical stabilization energy of 5�2 kJ mol-1 for the α- chlorine atom derived from these Arrhenius parameters is in excellent agreement with the value derived from kinetics of the isomerization of 1,4-dichlorobicyclo[2,2,0]hexane and from the thermochemistry of chloroethyl radicals.

scholarly journals Arrhenius parameters for the OH-initiated degradation of methyl crotonate, methyl-3,3-dimethyl acrylate, (E)-ethyl tiglate and methyl-3-butenoate over the temperature range of 288–314 K

RSC Advances ◽  
2016 ◽  
Vol 6 (59) ◽  
pp. 53723-53729 ◽  
Author(s):  
Juan P. Colomer ◽  
María B. Blanco ◽  
Alicia B. Peñéñory ◽  
Ian Barnes ◽  
Peter Wiesen ◽  
...  
Keyword(s):  
Relative Rate ◽  
Rate Coefficients ◽  
Oh Radicals ◽  
Arrhenius Parameters ◽  
Temperature Range

The relative-rate technique has been employed to obtain rate coefficients for the reactions of OH radicals with methyl crotonate, methyl-3,3-dimethyl acrylate, (E)-ethyl tiglate and methyl-3-butenoate between 288 and 314 K in 760 Torr of air.

Fouling Is the Beginning: Upcycling Biopolymer-Fouled Substrates for Fabricating High-Permeance Thin-Film Composite Polyamide Membranes

2020 ◽  
Author(s):  
Ruobin Dai ◽  
Hongyi Han ◽  
Tianlin Wang ◽  
Jiayi Li ◽  
Chuyang Y. Tang ◽  
...  
Keyword(s):  
Thin Film ◽  
High Pressure ◽  
End Of Life ◽  
Water Purification ◽  
Low Pressure ◽  
Polymeric Membranes ◽  
Membrane Recycling ◽  
Film Composite ◽  
Thin Film Composite ◽  
First Time

Commercial polymeric membranes are generally recognized to have low sustainability as membranes need to be replaced and abandoned after reaching the end of their life. At present, only techniques for downcycling end-of-life high-pressure membranes are available. For the first time, this study paves the way for upcycling fouled/end-of-life low-pressure membranes to fabricate new high-pressure membranes for water purification, forming a closed eco-loop of membrane recycling with significantly improved sustainability.

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