Show simple item record

dc.contributor.authorNoschese, Annarita
dc.date.accessioned2016-09-16T10:15:13Z
dc.date.available2016-09-16T10:15:13Z
dc.date.issued2016-03-16
dc.identifier.urihttp://hdl.handle.net/10556/2206
dc.description2014 - 2015it_IT
dc.description.abstractGold Nanoparticles are nanomaterials whose properties are completely different from the ones of the bulk material. Nowadays many chemists have been using them as catalysts which work under mild conditions and respect the principles green and sustainable chemistry. The increasing need for new heterogeneous catalysts to be applied in industrial processes encourages the finding of efficient and selective catalytic systems. The aim of the current PhD project is the synthesis of gold nanoparticles (AuNPs) supported onto a porous polymer matrix, consisting of syndiotactic polystyrene-co-cis-1,4-polybutadiene (sPSB) and the use of this hybrid material in redox reactions. Aerobic oxidative esterification of cinnamyl alcohol and nitroarenes reduction to amines were chosen as benchmark reactions to assess the activity and selectivity of the AuNPs-sPSB catalyst. In cinnamyl alcohol oxidation and esterification, a large number of products can be obtained, coming from oxidation, dehydrogenation or reduction pathways, but the catalytic system here presented resulted highly selective towards cinnamaldehyde and alkyl cinnamates. The synthetic protocol was successfully extended to p-substituted cinnamyl alcohols, and information about the effects of Electron Withdrawing or Electron Donating Groups on the esterification of cinnamyl alcohol were achieved. Nitroarenes reduction to aniline derivatives is a complex multistep reaction, since the main intermediates are azoxybenzene and azobenzene. Once again, the AuNPs-sPSB catalyst was selective in the aniline formation. Different reaction pathways have been proposed for this reaction; under the reaction conditions here used the condensation route proposed by Haber was detected. The access of reagents to the catalytic active site is facilitated by the presence of nanoporous polymeric matrix, whose role is to determine which species are able to permeate the polymeric matrix in order to reach the AuNPs. Different kinetic studies confirmed this initial hypothesis. In addition to the AuNPs-sPSB catalyst, gold colloids were immobilized on a polymeric support in order to investigate a different synthetic approach for the achievement of gold nanoparticles. Different supports have been tested, e.g. polyvinyl alcohol, polyvinylpyrrolidone, cetrimonium bromide and P123 (a poloxamer triblock co-polymer). The removal of the colloid stabilizer was evaluated through catalytic tests. [edited by author]it_IT
dc.language.isoenit_IT
dc.publisherUniversita degli studi di Salernoit_IT
dc.subjectGold nanoparticlesit_IT
dc.subjectPorous supportit_IT
dc.subjectHeterogeneous catalysisit_IT
dc.titleSustainable catalysis by polymer supported gold nanoparticlesit_IT
dc.typeDoctoral Thesisit_IT
dc.subject.miurCHIM/03 CHIMICA GENERALE E INORGANICAit_IT
dc.contributor.coordinatoreGuerra, Gaetanoit_IT
dc.description.cicloXIV n.s.it_IT
dc.contributor.tutorGrassi, Alfonsoit_IT
dc.contributor.cotutorLopez-Sanchez, Jose Ait_IT
dc.identifier.DipartimentoChimica e Biologiait_IT
 Find Full text

Files in this item

Thumbnail
Thumbnail
Thumbnail

This item appears in the following Collection(s)

Show simple item record