Pyrolysis of 1-methylcyclohexene and methylenecyclohexane

1976 ◽  
Vol 29 (3) ◽  
pp. 599 ◽  
Author(s):  
JL Garnett ◽  
WD Johnson ◽  
JE Sherwood
Keyword(s):  
Rate Constants ◽  
Alder Reaction ◽  
Diels Alder ◽  
Reaction Pathways ◽  
Main Reaction ◽  
Confidence Limits ◽  
Radical Chain ◽  
First Order ◽  
Diels Alder Reaction ◽  
Ring Fission

At 495� the decomposition of both 1-methylcyclohexene and methylenecyclohexane is homogeneous and first order overall, the rate constants (with 90% confidence limits) being (6.01 � 0.40) x 10-4 and (6.53 � 0.23) x 10-4 s-1 respectively. Pressure is not a good measure of the rate of decomposition of either isomer. Toluene inhibits the decomposition of both olefins, although the effect is more marked for the exo-isomer. The two main reaction pathways for 1-methylcyclohexene are a reverse Diels-Alder reaction, giving 2-methylbuta-1,3-diene and ethene, and a radical chain dehydrogenation to give toluene and benzene. Methylenecyclohexane cannot react through a reverse Diels-Alder reaction and ring fission gives a mixture of C3 and lower hydrocarbons. Dehydrogenation to give benzene and toluene is also important. Isomerization is a much more favoured pathway for methylenecyclohexane as expected from the relative thermodynamic stabilities of the isomers.

Polyimides from 2,5-bis[4-(4-aminophenoxy)benzoyl]furan and their thermal crosslinking reaction

2021 ◽  
pp. 095400832110522
Author(s):  
Kai Ma ◽  
Hanzhou Jiang ◽  
Guofei Chen ◽  
Wei Wang ◽  
Yonggang Zhang
Keyword(s):  
Alder Reaction ◽  
Diels Alder ◽  
Main Reaction ◽  
Crosslinking Reaction ◽  
Polyimide Films ◽  
Chemical Structures ◽  
Young’S Moduli ◽  
Diels Alder Reaction ◽  
Thermal Crosslinking ◽  
Ft Ir

Several polyimides were prepared via two-step polycondensation from novel 2,5-furandicarboxylic acid–based diamine, 2,5-bis[4-(4-aminophenoxy)benzoyl]furan, with commercial dianhydrides. The chemical structures of the monomers and polymers were characterized by FT-IR and NMR in detail, respectively. The polyimides exhibited high performances with 5 wt% weight loss temperatures of over 410 oC, glass transition temperatures of over 214 oC, and tensile strengths and Young’s moduli of up to 130 MPa and 3.2 GPa, respectively. The thermal crosslinking mechanism was studied by FT-IR, Raman spectroscopy, and model reaction analysis, which showed the Diels–Alder reaction between the furan group and diphenylethylene group was the main reaction. The crosslinked polyimide films showed improved solvent resistance, and thermal and mechanical properties.

Investigation Of Kinetic Regularities For Obtaining Methyl-1,3,4- Trimethylcyclohex-3-Encarboxylate By Reaction Of Diels-Alder

2019 ◽  
Vol 14 (4) ◽  
pp. 208-215
Author(s):  
I.S. Kostiv ◽  
R.I. Havryliv
Keyword(s):  
Rate Constants ◽  
Reaction Rate ◽  
Activation Parameters ◽  
Product Yield ◽  
Alder Reaction ◽  
Diels Alder ◽  
Molar Ratio ◽  
Target Product ◽  
Reaction Rate Constants ◽  
Diels Alder Reaction

Kinetics of the reaction of the cycloaddition of 2,3-dimethylbuta-1,3-diene (DMB) and methylmethacrylate (MMA) by the Diels-Alder reaction was studied. Reaction rate constants k = 4.4∙10-6 l/(mol∙s) at T = 403 K; k = 10.0∙10-6 l/(mol∙s) at T = 413 K; k = 15.8∙10-6 l/(mol∙s) at T = 423 K; k = 19.4∙10-6 l/(mol∙s) at T = 433 K and the activation parameters of the reaction Eakt = 75.2 kJ/mol, ΔS = -146.8 J/(mol∙K), ΔH = 73.9 kJ/mol were determined. Influence of temperature, molar ratio of reagents on the yield of the target product was investigated. At temperature increase from 403 to 433 K, methyl-1,3,4-trimethylcyclohex-3-encarboxylate (MTMCHC) yield increases from 78 % to 92 %. With further increase in temperature, DMB boils and MMA remains in a liquid state, accordingly it is not expected that the target product yield will materially increase. An increase in the excess of DMB: МMA from 1:1 to 2.5:1 makes it possible to increase yield of MTMCHC from 65 % to 92 %. The production of methyl-1,3,4-trimethylcyclohex-3-encarboxylate at the optimal conditions was established: temperature of 423−433 K and molar ratio of reagents DMB:MMA = 1.5:1, the yield of MTMCHC reaches 89−92 % at productivity of 101−105 g/(l·h). Based on the obtained reaction rate constants and the activation parameters of the [4+2]-cyclic addition of 2,3-dimethylbuta-1,3-diene and methylmethacrylate, it was found that the reaction under study is subject to the kinetic law of the second order.

scholarly journals N-hexylpyridinium bis(trifluoromethylsulfonyl)imide and Lewis acids — catalytic systems for Diels-Alder reaction

2011 ◽  
Vol 9 (1) ◽  
pp. 192-198 ◽  
Author(s):  
Bożena Bittner ◽  
Ewa Janus ◽  
Eugeniusz Milchert
Keyword(s):  
Ionic Liquid ◽  
Rate Constants ◽  
Lewis Acids ◽  
Reaction Rate ◽  
Alder Reaction ◽  
Diels Alder ◽  
Catalytic Systems ◽  
Reaction Rate Constants ◽  
Diels Alder Reaction ◽  
Reaction Media

AbstractA comparative study of the Diels-Alder reactions between cyclopentadiene (1) and dienophiles (2 a–c) in N-hexylpyridinium bis(trifluoromethylsulfonyl)imide in a temperature range of 20–45°C is reported. The reaction rate constants and activation energies were calculated. Moreover, the catalytic systems based on N-hexylpyridinium bis(trifluoromethylsulfonyl)imide and Lewis acids were tested as a reaction media to perform the Diels-Alder reaction. Yb, Y, Mg, Zn triflates and chlorides (0.005 to 0.1 mmol) were used as catalysts. The recycling of catalytic system consisted of YCl3 and ionic liquid was performed.

Catalytic Approach to Unsymmetrical [7]-Helical Indenofluorenes: Cyclotrimerization vs. Dehydro-Diels-Alder Reaction Pathways.

2021 ◽  
Author(s):  
Ilaria Caivano ◽  
Selina Bingel ◽  
Ivana Císařová ◽  
David Nečas ◽  
Martin Kotora
Keyword(s):  
Alder Reaction ◽  
Diels Alder ◽  
Reaction Pathways ◽  
Diels Alder Reaction

The Diels-Alder Reaction of 2-Ethenyl-1,4-Benzodioxin: A New and Simple Synthesis of Bisaryl Ethers

Synlett ◽  
1989 ◽  
Vol 1989 (01) ◽  
pp. 30-32
Author(s):  
Thomas V. Lee ◽  
Alistair J. Leigh ◽  
Christopher B. Chapleo
Keyword(s):  
Alder Reaction ◽  
Diels Alder ◽  
Simple Synthesis ◽  
Diels Alder Reaction

Asymmetric aza-Diels-Alder reaction of Danishefsky’s diene with imines in a chiral reaction medium

2006 ◽  
Author(s):  
Giang Vo-Thanh ◽  
Bruce Pégot ◽  
Olivier Van Buu ◽  
Didier Gori
Keyword(s):  
Reaction Medium ◽  
Alder Reaction ◽  
Diels Alder ◽  
Diels Alder Reaction ◽  
Danishefsky's Diene

The intermolecular anthracene-transfer in a regiospecific antipodal C60 difunctionalization

2020 ◽  
Author(s):  
Radu Talmazan ◽  
Klaus R. Liedl ◽  
Bernhard Kräutler ◽  
Maren Podewitz
Keyword(s):  
Noncovalent Interactions ◽  
Interaction Model ◽  
Alder Reaction ◽  
Diels Alder ◽  
Stacking Interactions ◽  
Pi Stacking ◽  
Diels Alder Reaction ◽  
Double Decker ◽  
Anthracene Molecule ◽  
New Strategies

We analyze the mechanism of the topochemically controlled difunctionalization of C60 and anthracene, where an anthracene molecule is transferred from one C60 monoadduct to another one under exclusive formation of equal amounts of C60 and the difficult to make antipodal C60 bisadduct. Our herein disclosed dispersion corrected DFT studies show the anthracene transfer to take place in a synchronous retro Diels-Alder/Diels-Alder reaction: an anthracene molecule dissociates from one fullerene under formation of an intermediate, while already undergoing stabilizing interactions with both neighboring fullerenes, facilitating the reaction kinetically. In the intermediate, a planar anthracene molecule is sandwiched between two neighboring fullerenes and forms equally strong "double-decker" type pi-pi stacking interactions with both of these fullerenes. Analysis with the distorsion interaction model shows that the anthracene unit of the intermediate is almost planar with minimal distorsions. This analysis sheds light on the existence of noncovalent interactions engaging both faces of a planar polyunsaturated ring and two convex fullerene surfaces in an unprecedented 'inverted sandwich' structure. Hence, it sheds light on new strategies to design functional fullerene based materials.<br>

Natural Products Biosynthesis Involving a Putative Diels-Alder Reaction

2016 ◽  
Vol 20 (22) ◽  
pp. 2421-2442 ◽  
Author(s):  
Kévin Cottet ◽  
Maria Kolympadi ◽  
Dean Markovic ◽  
Marie-Christine Lallemand
Keyword(s):  
Natural Products ◽  
Alder Reaction ◽  
Diels Alder ◽  
Diels Alder Reaction

Aza-Diels-Alder Reaction: An Efficient Approach for Construction of Heterocycles

2014 ◽  
Vol 18 (12) ◽  
pp. 1586-1620 ◽  
Author(s):  
Manas M. Sarmah ◽  
Dipak Prajapati
Keyword(s):  
Alder Reaction ◽  
Diels Alder ◽  
Efficient Approach ◽  
Diels Alder Reaction

Aza-Diels-Alder Reaction Between 1,2-Diaza-1,3-dienes and β-Aryl-α,β-unsaturated Carbonyl Compounds. Easy One-pot Entry to 2’-Oxo-imidazo[1’,5’- f]tetrahydropyridazine

2014 ◽  
Vol 10 (6) ◽  
pp. 951-960
Author(s):  
Orazio Attanasi ◽  
Luca Bianchi ◽  
Maurizio D’Auria ◽  
Gianfranco Favi ◽  
Fabio Mantellini ◽  
...  
Keyword(s):  
Carbonyl Compounds ◽  
Alder Reaction ◽  
Diels Alder ◽  
One Pot ◽  
Diels Alder Reaction
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