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41.
Maxime Guitet Pinglu Zhang Filipa Marcelo Coralie Tugny Jesús Jimnez‐Barbero Olivier Buriez Christian Amatore Virginie Mouris‐Mansuy Jean‐Philippe Goddard Louis Fensterbank Yongmin Zhang Sylvain Roland Mickaël Mnand Matthieu Sollogoub 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2013,125(28):7354-7359
42.
Sylvain Achelle Samia Kahlal Jean-Yves Saillard Nolwenn Cabon Bertrand Caro Françoise Robin-le Guen 《Tetrahedron》2014
Thirteen novel dipolar and V-shaped chromophores with pyranylidene electron-donating part, diazine electron-withdrawing part and various π-linkers were synthesized. The extent of intramolecular charge transfer, structure-property relationships and optical properties were further investigated by UV/Vis absorption, electrochemistry, and DFT calculations. 相似文献
43.
44.
Chahinez Aouf Christine Le Guernevé Sylvain Caillol Hélène Fulcrand 《Tetrahedron》2013,69(4):1345-1353
The O-alkylation reaction by epichlorohydrin of some natural phenolic compounds such as 4-methylcatechol, gallic acid, protocatechuic acid, pyrogallol and resorcinol was investigated. Phenolic compounds reacted first with epichlorohydrin in the presence of benzyltriethylammonium chloride as phase transfer catalyst. Then, an aqueous solution of sodium hydroxide was added.It was demonstrated that the two competitive mechanisms involved in the O-alkylation reaction were highly dependent of the starting material. The O-alkylated products obtained in this reaction could be further used as bisphenol A substitutes in the synthesis of epoxy resins pre-polymers. 相似文献
45.
46.
Sylvain Cousinet Ali Ghadban Imène Allaoua Frédéric Lortie Daniel Portinha Eric Drockenmuller Jean‐Pierre Pascault 《Journal of polymer science. Part A, Polymer chemistry》2014,52(23):3356-3364
Vinyl levulinate (VL) is used as a biobased reactive diluent in styrene (St)‐free unsaturated polyester resins (UPR). The reactivity ratios for the radical copolymerization of VL with diethyl fumarate (DEF) are determined by the Jaacks method (rVL = 0.01 and rDEF = 0.81 at 60 °C in DMSO‐d6). The properties of UPRs having a stoichiometric ratio between unsaturated groups from the UPR and either St or VL are compared. Defect‐free, slightly yellow, transparent, and rigid thermosets are obtained after a mild curing cycle. Due to unfavorable reactivity ratios about 5.5 wt % of unpolymerized VL remains inside the network and acts as plasticizer. Consequently, compared with St‐based ones, VL‐based UPRs exhibit lower α relaxation (Tα = 180 and 100 °C, respectively), lower elastic moduli at the rubbery plateau (G′ = 108 and 107 Pa) and lower mechanical properties as measured by three points bending tests. Strain at break (εf = 1.8 ± 0.2%) and Charpy impact strength (~2.7 ± 0.3 kJ m?2) are comparable independently of the RD chemical nature. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 3356–3364 相似文献
47.
Dr. Sébastien Lemouzy Florian Cuminet Dimitri Berne Dr. Sylvain Caillol Dr. Vincent Ladmiral Prof. Rinaldo Poli Dr. Eric Leclerc 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(48):e202201135
Vitrimers are a third class of polymers gathering the mechanical properties and solvent resistance of 3D thermosets and the reprocessability of thermoplastics. This unique behaviour is due to the triggering of certain covalent exchange reactions that allow the network to rearrange upon application of a stimulus. The constitutive feature of vitrimers is the adoption of a glass-like viscosity during the rearrangement of the network, often due to an associative mechanism for the exchange reaction. Transesterification networks are one of the most studied type of vitrimers that usually require the incorporation of a catalyst, implying the associated drawbacks. Following up on a recent report on catalyst-free transesterification vitrimers in which the ester functions are particularly reactive thanks to the presence of fluorine atoms in α- or β-position, parallel DFT calculations and an experimental kinetic study on model molecules are presented in order to quantitatively assess the effect of neighbouring fluorinated groups on the transesterification reaction rate. 相似文献
48.
Riadi Y Abrouki Y Mamouni R El Haddad M Routier S Guillaumet G Lazar S 《Chemistry Central journal》2012,6(1):60
ABSTRACT: Two efficient reactions were successfully carried out using Animal Bone Meal (ABM) and potassium fluoride or sodium nitrate doped ABMs as new heterogeneous catalysts under very mild conditions. After preparation and characterization of the catalysts, we first report their use in a simple and convenient synthesis of various chalcones by Claisen-Schmidt condensation and then in an aza-Michael addition involving several synthesized chalcones with aromatic amines. All the reactions were carried out at room temperature in methanol; the chalcone synthesis was also achieved in water environment under microwave irradiation. Doping ABM enhances the rate and yield at each reaction. Catalytic activities are discussed and the ability to re-use the ABM is demonstrated. RESULTS: For Claisen-Schmidt the use of ABM alone, yields never exceeded 17%. In each entry, KF/ABM and NaNO3/ABM (79-97%) gave higher yields than using ABM alone under thermic condition. Also the reaction proceeded under microwave irradiation in good yields (72-94% for KF/ABM and 81-97% for NaNO3/ABM) and high purity. For aza-Michael addition the use of ABM doped with KF or NaNO3 increased the catalytic activity remarkably. The very high yields could be noted (84-95% for KF/ABM and 81-94% for NaNO3/ABM). CONCLUSION: The present method is an efficient and selective procedure for the synthesis of chalcones anaaza-Michael adducts. The ABM and doped ABMs are a new, inexpensive and attractive solid supports which can contribute to the development of catalytic processes and reduced environmental problems. 相似文献
49.
50.
Charles Audet Anthony Guillou Pierre Hansen Frédéric Messine Sylvain Perron 《Journal of Global Optimization》2011,49(3):467-480
The hexagon and heptagon with unit diameter and maximum sum of Euclidean distances between vertices are determined by enumerating
diameter configurations, and by using a branch and cut algorithm for nonconvex quadratic programming. Lower bounds on the
value on this sum are presented for polygon with a larger number of vertices. 相似文献