Preparation of Thermostable Rigid Foams by Control of the Reverse Diels—Alder Reaction During the Cross-Linking of Bis-nadimide Oligomers

1997 ◽  
pp. 37-53 ◽  
Author(s):  
L. Dutruch ◽  
M. Senneron ◽  
M. Bartholin ◽  
P. Mison ◽  
B. Sillion
Keyword(s):  
Alder Reaction ◽  
Diels Alder ◽  
Cross Linking ◽  
Diels Alder Reaction ◽  
The Cross ◽  
Rigid Foams

scholarly journals New insights into the cross-linking and degradation mechanism of Diels–Alder hydrogels

2015 ◽  
Vol 3 (3) ◽  
pp. 449-457 ◽  
Author(s):  
Susanne Kirchhof ◽  
Andrea Strasser ◽  
Hans-Joachim Wittmann ◽  
Viktoria Messmann ◽  
Nadine Hammer ◽  
...  
Keyword(s):  
Ring Opening ◽  
Degradation Mechanism ◽  
Alder Reaction ◽  
Diels Alder ◽  
Cross Linking ◽  
Diels Alder Reaction ◽  
Maleamic Acid ◽  
The Cross ◽  
Hydrolysis Of

Degradation of Diels–Alder hydrogels occurs by retro-Diels–Alder reaction followed by OH−-catalyzed ring-opening hydrolysis of maleimide groups to unreactive maleamic acid derivatives.

scholarly journals Towards Thermally Reversible Networks Based on Furan-Functionalization of Jatropha Oil

Molecules ◽  
2020 ◽  
Vol 25 (16) ◽  
pp. 3641
Author(s):  
Frita Yuliati ◽  
Peter J. Deuss ◽  
Hero J. Heeres ◽  
Francesco Picchioni
Keyword(s):  
Ring Opening ◽  
Alder Reaction ◽  
Diels Alder ◽  
Epoxide Ring ◽  
Cross Linking ◽  
Jatropha Oil ◽  
Optimum Conditions ◽  
Epoxide Ring Opening ◽  
Diels Alder Reaction ◽  
Ring Opening Reaction

A novel biobased monomer for the preparation of thermally reversible networks based on the Diels-Alder reaction was synthesized from jatropha oil. The oil was epoxidized and subsequently reacted with furfurylamine to attach furan groups via an epoxide ring opening reaction. However, furfurylamine also reacted with the ester groups of the triglycerides via aminolysis, thus resulting in short-chain molecules that ultimately yielded brittle thermally reversible polymers upon cross-linking via a Diels-Alder reaction. A full-factorial experimental design was used in finding the optimum conditions to minimize ester aminolysis and to maximize the epoxide ring opening reaction as well as the number of furans attached to the modified oil. The optimum conditions were determined experimentally and were found to be 80 °C, 24 h, 1:1 molar ratio, with 50 mol % of LiBr with respect to the modified oil, resulting in 35% of ester conversion, 99% of epoxide conversion, and an average of 1.32 furans/triglyceride. Ultimately, further optimization by a statistical approach led to an average of 2.19 furans per triglyceride, which eventually yielded a flexible network upon cross-linking via a Diels-Alder reaction instead of the brittle one obtained when the furan-functionalization reaction was not optimized.

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

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
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