85 research outputs found
Thermoremendable Styrenic Polymers by Controlled Radical Copolymerization of Styrene with bioderived 2-vinylfuran
No full textThermoremendable Styrenic Polymers by Controlled Radical Copolymerization of Styrene with bioderived 2-vinylfuran
A. Grassi,* A. Buonerba, C. Capacchione, S. Milione
Department of Chemistry and Biology “Adolfo Zambelli”, University of Salerno – Italy
CIRCC - Interuniversity Consortium on Chemical Reactivity and Catalysis
*Corresponding author: [email protected]
Keywords: Biosourced olefins, functional olefin copolymer, furan-maleimide Diels Alder reaction.
Abstract
2-vinylfuran (2VF) is a bioderived olefin synthesized by Peterson methylenation of furfural, a cheap platform molecule resulting from acid catalyzed hydrolysis and dehydration of pentosanes from lignocellulosic biomass. Ideal ATR copolymerization of styrene with 2VF yielded random copolymers (S-co-2VFs) in a wide range of composition and high monomer conversion.[1] The S-co-2VFs are stable for years in solution and solid state at room temperature; radical oxidation of the furan moieties starts in air at temperature higher than 120°C whereas thermal degradation occurs at 380°C. Diels Alder (DA) cycloaddition reaction of S-co-2VFs with bismaleimide (BMI) produces thermorevesible crosslinks: the thermodynamic and kinetic parameters of this reaction were investigated by NMR and FT-IR spectroscopy to assess the optimal condition for high crosslink degree and self healing conditions. The mechanical properties of the S-co-2VFs, before and after reaction with BMI, were compared using INSTRON analysis and nanoidentation of polymeric thin films by Atomic Force Microscopy.[2] Moreover simple thermal treatment of mechanically fractured films of S-co-2VFs reacted with BMI allowed full repairing in 80 min (Figure 1).
Scheme. Diels Alder reaction of S-co-2VFs with BMI.
Figure 1. Fractured (a) and healed (b) polymer film of S-co-2VF crosslinked with BMI after thermal annealing at 150°C.
References
[1] S. Ortega Sáncheza, F. Marra, A. Dibenedetto, M. Aresta, A. GrassiMacromolecules 2014, 47, 7129−7137.
[2] A. Grassi, A. Buonerba, C. Capacchione, S. Milione ACS National Meeting San Diego (USA) 2016
Supplementary_Material – Supplemental material for Performance of tumor testing for Lynch syndrome identification in patients with colorectal cancer: A retrospective single-center study
No full textSupplemental material, Supplementary_Material for Performance of tumor testing for Lynch syndrome identification in patients with colorectal cancer: A retrospective single-center study by Stefano Signoroni, Maria Grazia Tibiletti, Maria Teresa Ricci, Massimo Milione, Federica Perrone, Valeria Pensotti, Anna Maria Chiaravalli, Ileana Carnevali, Alberto Morabito, Lucio Bertario and Marco Vitellaro in Tumori Journal</p
Organocatalytic Cycloaddition of CO2 to Glycidol: the Dual Role of Substrate and Catalyst Played by a Hydroxy-Functionalized Epoxide
No full textOrganocatalytic Cycloaddition of CO2 to Glycidol: the Dual Role of Substrate and Catalyst Played by a Hydroxy-Functionalized Epoxide
Francesco Della Monica,1,2Antonio Buonerba, 1,2 Stefano Milione, 1,2Carmine Capacchione,, 1,2 Alfonso Grassi1,2
1Dipartimento di Chimica e Biologia "Adolfo Zambelli", Università degli Studi di Salerno, via Giovanni Paolo II, 84084 Fisciano(SA), Italy
2Interuniversity Consortium on Chemical Reactivity and Catalysis, CIRCC, via Celso Ulpiani 27, 70126 (BA), Italy *Corresponding author: [email protected]
Keywords: Carbon dioxide, Epoxides, Glycerolcarbonate
Abstract
The coupling of carbon dioxide with epoxides represents a very attractive reaction for the possibility of recovering a waste, namely CO2, by means of a 100% atom-economical process leading to value added products such as cyclic carbonates.[1] In the last decade, the development of CO2 chemistry parallely to the increasing production of biodiesel from vegetable oils offered to the market a new cheap raw material as glycerol whose decreasing price has triggered a growing interest in the efficient conversion of this molecule to value added commodities. Among the possible derivatives, glycerol carbonate (GC) is a particularly interesting target since it has a potential application as low Volatile Organic Compound (VOC), a bio-based alternative to organic solvents from non-renewable resources.[2]
Scheme 2. Synthesis of glycerol carbonate (GC) from glycidol and CO2
Here we report on the conversion of glycidol to glycerol carbonate (GC) in excellent yields (99%) and short reaction time (3h), by coupling with CO2 in the presence of tetrabutylammonium bromide (TBAB) as activator and under mild reaction conditions (T = 60°C, P(CO2) = 1MPa). The unusual reactivity of glycidol compared to other epoxides is due to the presence of the hydroxyl functionality. DFT calculations supported by 1H NMR experiments indeed revealed that the unique behaviour of this epoxide is due to the formation of a dimeric structure driven by intermolecular hydrogen bonds that activates the oxirane ring toward the nucleophilic attack of the bromide anion, leading to the formation of GC. Furthermore, the glycidol/TBAB binary system acts as efficient organocatalyst for the coupling of CO2 with other epoxides.
References
[1] (a) C. Martín, G. Fiorani and A. W. Kleij, ACS Catal., 2015, 5, 1353-1370; (b) J. W. Comerford, I. D. V. Ingram, M. North and X. Wu, Green Chem., 2015, 17, 1966-1987.
[2] M. O. Sonnati, S. Amigoni, E. P. T. de Givenchy, T. Darmanin, O. Choulet and F. Guittard, Green Chem., 2013, 15, 283–306
L'uso dei mooc come strumento di lifelong learning: uno sguardo sugli scenari
No full textLo scenario educativo del 2020 è stato caratterizzato dall’incremento di attività di distance learning sia nei contesti scolastici e universitari sia in quelli lavorativi. Fra i diversi strumenti di apprendimento a distanza spiccano i MOOCs (Massive Open Online Courses), presenti nello spazio educativo mondiale ed Europeo da più di dieci anni, questi sono diventati famosi in Italia durante la pandemia 2020. Nel seguente capitolo si produrrà un’analisi dello scenario europeo e italiano in relazione al Lifelong Learning (LLL apprendimento continuo), ai Mooc come strumento importante per le pratiche di Life Longlearning e come le competenze digitali siano il ponte fra questi due mondi educativi
Selective and Efficient Reduction of Nitrobenzene to Aniline catalyzed by AuNPs Embedded in a Nanoporous Crystalline Polymeric Support
No full textCongresso Divisione Chimica Industriale
Salerno, Settembre 2015
Selective and Efficient Reduction of Nitrobenzene to Aniline catalyzed
by AuNPs Embedded in a Nanoporous Crystalline Polymeric Support
Annarita Noschese1*, Antonio Buonerba1, Carmine Capacchione1, Stefano Milione1, Alfonso Grassi1
1 - Dipartimento di Chimica e Biologia, Università degli Studi di Salerno, Via Giovanni Paolo II - 84084 Fisciano (SA), Italy, and CIRCC-Bari, Italy
Abstract
Supported Gold Nanoparticles (AuNPs) efficiently catalyze both oxidation and reduction reactions. E.g. aerobic oxidation of alcohols and cross coupling reactions of alcohols leading to esters, amide, imine have been widely and successfully explored [1]. On the other side the reduction of nitroarenes to anilines using NaBH4, H2, silanes, formic acid, CO/H2O is a benchmark reaction for testing their catalytic performances in reduction reactions [2].
During reaserch efforts many supports have been exploited (carbon based supports, polymers, inorganic oxides) but their role is still under discussion. A semicrystalline porous polymeric support, consisting of syndiotactic polystyrene-co-cis-1,4-polybutadiene [3] has been successfully tested in our group and the AuNPS embedded in this polymer matrix (AuNPs-sPSB) were investigated in the reduction of nitrobenzene to aniline. The polymorphic behaviour of the host polymer matrix has been studied to optimize the catalyst performances. The nanoporous crystalline forms of the sPSB matrix, namely and , allowed a total conversion of nitrobenzene in 40 min at room temperature, with 100% selectivity in aniline. On the contrary the not permeable crystalline form gave a less reactive and selective catalyst; actually azobenzene and azoxybenzene were detected as intermediates compounds providing information on the cascade of the reduction reactions and the global reaction mechanism. Among the catalysts to date reported in the literature, the AuNPs-sPSB catalyst showed the highest activity (TOF=6000 h-1). The catalyst is very stable under the reaction conditions and reusable for at least three times without loss of catalytic activity.
Keywords: Gold Nanoparticles, Polymeric Matrix, Reduction.
* Corresponding author: [email protected]
References
[1] A. Corma, H. Garcia, Chem. Soc. Rev. 37 (2008) 2096
[2] S. Fountoulaki, V. Daikopoulou, P. L. Gkizis, I. Tamiolakis, G.S. Armatas, I. N. Lykakis, ACS Catal. 4 (2014) 3504; X. Liu, S. Ye, H.-Q. Li, Y.-M. Liu, Y. Cao, K.-N. Fan, Catal. Sci. Technol. 3 (2013) 3200; L. He, L.-C. Wang, H. Sun, J. Ni, Y. Cao, H.-Y. He, K.-N. Fan, Angew. Chem. Int. Ed. 48 (2009) 9538.
[3] A. Buonerba, C. Cuomo, S. Ortega Sánchez, P. Canton, A. Grassi, Chem. Eur. J. 18 (2012) 709; A. Buonerba, A. Noschese, A. Grassi, Chem. Eur. J. 20 (2014) 5478
Il museo erbario del Dipartimento di Biologia Vegetale
No full textDopo un'introduzione sulle modalità di realizzazione di un erbario e sul ruolo ed attualità degli erbari, viene delineata la storia del Museo Erbario dell'Università Sapienza e presentato il patrimonio dello stesso. Attualmente le collezioni sono organizzate in sei erbari e constano complessivamente di più di un milione di esemplari
La città e le comunità urbane
No full textIl saggio propone una ricostruzione ragionata dell'evoluzione della città in Italia a partire dal dopoguerra ai giorni nostri, centrando in particolare l'attenzione sui principali processi di mutamento e su alcuni fenomeni che ne sono derivat
La comunicazione, le città e le società locali
No full textIl saggio analizza il ruolo della comunicazione in alcuni processi di governance urbana, con particolare riferimento alla risoluzione dei conflitti territoriali, alle valutazioni di impatto urbano degli interventi ed ai meccanismi partecipativ
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