A study of polymers obtained by oxidative coupling of furan monomers (original) (raw)
Related papers
Electron paramagnetic resonance studies on oxidative polymerization mechanism of furan derivatives
Journal of Polymer Science Part B: Polymer Physics, 1998
The oxidative polymerization of furan, 3-methylfuran and 2,2 ,5,2Љ-terfuran, induced by iodine in organic solvents having different donicity, was investigated by time-resolved electron paramagnetic resonance (EPR) spectroscopy. The reaction was monitored starting from the onset of the process and radical species arising from the monomers in early stages of the polymerization reaction were detected. The comparison between experimental and theoretical hyperfine coupling constants, obtained by simulated EPR spectra and theoretical ab initio calculations, respectively, allowed one to structurally characterize the above radical species, thus enabling mechanistic conclusions about oxidative coupling. Moreover, the analysis of the time evolution of EPR spectrum during the oxidative polymerization process was used for evaluating the relative amount of localized and mobile radical species along the polymer backbone, thus getting preliminary information about conjugation extent and electroconducting properties of the final material.
Furan chemistry and ionic polymerization: Mechanisms and structures
Makromolekulare Chemie. Macromolecular Symposia, 1992
The polymerization of furanic monomers using cationic and anionic initiators often leads to peculiar responses due to the specific chemistry of the heterocycle. The understanding of these mechanisms can help minimizing the problems encountered or, better still, exploiting them to synthesize novel macromolecular structures. The examples given here comprise the preparation of block copolymers and functionalized, polyconjugated or telechelic oligomers, the investigation of colour-forming and branching reactions and the elaboration of powerful Lewis-base resins. 0 1992 Hiithig & Wepf Verlag, Basel CCC 0258-032UW$04.00
Materials from renewable resources based on furan monomers and furan chemistry: work in progress
Journal of Materials Chemistry, 2009
The polymerisation of furan monomers and the exploitation of some of the chemical peculiarities of the furan heterocycle have generated a wide diversity of macromolecular materials based on renewable resources. We present here recent contributions to this field, including ongoing studies on the synthesis and characterisation of novel furan polyesters and on the application of the Diels-Alder reaction to the preparation of linear and branched thermally reversible polyadducts.
Canadian Journal of Chemistry, 1980
Dimerization of tetraacetylethylene (TAE) 1 has led to a spiro[furan-2(5H),2′(3′H)-furo[2,3-b]furan], whose structure was established by X-ray analysis. The trend of TAE to furan ring closure was confirmed by the reaction with ethyl vinyl ether, where the first product of the reaction, the pyran adduct 8, smoothly rearranged to a furo[2,3-b]furan derivative 9.
Topics in Catalysis, 2000
In this review, an overview is given on the last development of catalytic methods for the preparation of substituted furans from carbohydrates and ensuing polymers. The review starts with the recent aspects in the synthesis of some key furan monomers in the presence of solid catalysts. In the second part, selected examples are given of polymerization systems leading to furan-based materials with promising properties, thus constituting a serious alternative to petroleum-based counterparts. Finally, a short examination is given on what could be the future of furan chemistry with the recent development of ionic liquids as solvents.
A Novel Poly{(2,5-diyl furan) (benzylidene)}: A New Synthetic Approach and Electronic Properties
ISRN Physical Chemistry, 2012
A new conjugated aromatic poly[(furan-2, 5-diyl)-co-(benzylidene)] has been prepared by polycondensation of benzaldehyde and furan catalyzed by Maghnite-H + . Maghnite-H + is a montmorillonite sheet silicate clay, which exchanged with protons. These polymers can be dissolved in high polar solvents such as DMSO, DMF, THF, or CHCl 3 A kind of band-gap conjugated poly[(furan-2, 5-diyl)-co-(benzylidene)] has been synthesized by a simple method and characterized by 1 HNMR, 13 CNMR, FT-IR, and UV-Vis. The result reveals that the band-gap of the PFB conjugated polymer has an optical band gap of 2.2 eV.
Ab Initio Study on the Photochemical Isomerization of Furan Derivatives
The Journal of Organic Chemistry, 2000
The photochemical isomerization reactions of furan, 2-methylfuran, 2-trimethylsilylfuran, and furan-2-carbonitrile were studied using ab initio methods. The results are in agreement with the previously reported data obtained through semiempirical methods. In particular, the sensitized irradiation of furan derivatives populates the first excited triplet state of the furan, and this triplet state can evolve only through O-C R cleavage. The selection of the bond to be broken can depend on energetic factors (furan-2-carbonitrile) or on kinetic factors (2-methylfuran, 2-trimethylsilylfuran). The direct irradiation of furan derivatives populates the singlet excited state and leads to a conversion into the Dewar isomer or into the corresponding triplet state through the usual intersystem crossing procedure. The efficiency of these processes determines the presence or the absence of isomerized furan derivatives in the reaction mixtures.