The sp2 carbon allotropes (i.e. graphite, graphene and carbon nanotubes) are gaining attention in many research communities due to their properties and their possible applications. In particular, in the chemical catalysis field, they proved to be effective as catalysts themselves or as catalyst supports. sp2 carbon allotropes show their huge potential as catalytic materials only when finely dispersed in an adapt organic solvent, maximizing their catalytic surface area and preserving their nanoscale size. However, different methods have been developed in order to increase the carbon allotrope solubility also in polar solvents, e.g. water, and avoid its aggregation and precipitation. This thesis work focuses on the employing and optimization of a copolymer/graphene non-covalent system as catalytic nanoreactor suitable for unfavored organic reactions in water. The nanoreactor performances have been evaluated as function of the amphiphilic copolymer employed to disperse and stabilize the carbon allotrope in water. Different polymerization techniques have been used in order to synthetize copolymers with different macromolecular structures and their ability to stabilize the copolymer/graphene adduct in water has been tested. Moreover, different functionalized sp2 carbon allotropes have been tested as active catalytic component in the already mentioned nanoreactor. In particular, the developed systems proved to be particularly effective in the catalysis of imine formation from aldehydes and primary amines in water, with yields around 90% at room temperature.
L’interesse per gli allotropi sp2 del carbonio (ad esempio la grafite, il grafene e i nanotubi di carbonio) sta aumentando in molte comunità scientifiche per via delle loro particolari proprietà e delle loro possibili applicazioni. Nel campo della catalisi chimica, essi possono essere impiegati come catalizzatori o come supporto per catalizzatori. Gli allotropi sp2 del carbonio dimostrano il loro elevato potenziale quando sono finemente dispersi in un solvente organico, massimizzando così l’area superficiale catalitica e restando nell’ordine di grandezza della nanoscala. Diversi metodi sono stati sviluppati per aumentare la loro solubilità in solventi polari, come ad esempio l’acqua, in modo da evitarne l’aggregazione e sedimentazione. Questa tesi si focalizza proprio sull’impiego e l’ottimizzazione di un sistema non covalente copolimero/grafene utilizzabile come nanoreattore per condurre reazioni di sintesi organica in acqua. Le prestazioni del nanoreattore sono state valutate in funzione del copolimero utilizzato per disperdere e stabilizzare l’allotropo del carbonio in acqua. Sono stati usati diverse tecniche di polimerizzazione per ottenere copolimeri con strutture macromolecolari diverse e la loro abilità nello stabilizzare il grafene in acqua è stata valutata. Inoltre sono stati testati diversi allotropi sp2 del carbonio come catalizzatore nell’addotto. Diverse reazioni di sintesi organica sono state condotte utilizzando il nanoreattore per provarne l’efficacia. In particolare, il sistema catalitico sviluppato si è dimostrato efficace nella sintesi in acqua di immine a partire da aldeidi e ammine, con rese superiori al 90% già a temperatura ambiente.
Optimization of polymer/graphene catalytic nanoreactors for organic reactions
TOSCANO, LUCA
2018/2019
Abstract
The sp2 carbon allotropes (i.e. graphite, graphene and carbon nanotubes) are gaining attention in many research communities due to their properties and their possible applications. In particular, in the chemical catalysis field, they proved to be effective as catalysts themselves or as catalyst supports. sp2 carbon allotropes show their huge potential as catalytic materials only when finely dispersed in an adapt organic solvent, maximizing their catalytic surface area and preserving their nanoscale size. However, different methods have been developed in order to increase the carbon allotrope solubility also in polar solvents, e.g. water, and avoid its aggregation and precipitation. This thesis work focuses on the employing and optimization of a copolymer/graphene non-covalent system as catalytic nanoreactor suitable for unfavored organic reactions in water. The nanoreactor performances have been evaluated as function of the amphiphilic copolymer employed to disperse and stabilize the carbon allotrope in water. Different polymerization techniques have been used in order to synthetize copolymers with different macromolecular structures and their ability to stabilize the copolymer/graphene adduct in water has been tested. Moreover, different functionalized sp2 carbon allotropes have been tested as active catalytic component in the already mentioned nanoreactor. In particular, the developed systems proved to be particularly effective in the catalysis of imine formation from aldehydes and primary amines in water, with yields around 90% at room temperature.File | Dimensione | Formato | |
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Descrizione: Tesi - Optimization of polymer/graphene catalytic nanoreactors for organic reactions
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https://hdl.handle.net/10589/148467