Alexios Grigoropoulos

Dr. Alexios Grigoropoulos

Creative Nano PC, Athens, Attikí, Greece
orcid

Research Focus & Metrics

Academic Career Length

21Years (2006-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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12 February 2016 in ChemSusChem
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NPNoémie Perret
Noémie Perret
Alexios GrigoropoulosAlexios Grigoropoulos
Alexios Grigoropoulos
MZMarco Zanella
Marco Zanella
TMTroy D. Manning
Troy D. Manning
JCJohn B. Claridge
John B. Claridge
MRMatthew J. Rosseinsky
Matthew J. Rosseinsky

5 November 2013 in Inorganic Chemistry
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Journal Article
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Alexios GrigoropoulosAlexios Grigoropoulos
Alexios Grigoropoulos
MPMichael Pissas
Michael Pissas
PPPatroklos Papatolis
Patroklos Papatolis
Vassilis PsycharisVassilis Psycharis
Vassilis Psycharis
PKPanayotis Kyritsis
Panayotis Kyritsis
YSYiannis Sanakis
Yiannis Sanakis

8 March 2017 in Green Chemistry
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RRRubén Ramos
Rubén Ramos
Alexios GrigoropoulosAlexios Grigoropoulos
Alexios Grigoropoulos
NPNoémie Perret
Noémie Perret
MZMarco Zanella
Marco Zanella
AKAlexandros P. Katsoulidis
Alexandros P. Katsoulidis
MRMatthew J. Rosseinsky
Matthew J. Rosseinsky
The production of cyclopentanone derivatives from 5-hydroxymethylfurfural (HMF) using non-noble metal based catalysts is reported for the first time. Five different mixed oxides containing Ni, Cu, Co, Zn and Mg phases on an Al-rich amorphous support were prepared and characterised (XRD, ICP, SEM, TEM, H2-TPR, NH3/CO2-TPD and N2 sorption). The synthesised materials resulted in well-dispersed high metal loadings in a mesoporous network, exhibiting acid/base properties. The catalytic performance was tested in a batch stirred reactor under H2 pressure (20–50 bar) in the range T = 140–180 °C. The Cu–Al2O3 and the Co–Al2O3 catalysts showed a highly selective production of 3-hydroxymethylcyclopentanone (HCPN, 86%) and 3-hydroxymethylcyclopentanol (HCPL, 94%), respectively. A plausible reaction mechanism is proposed, clarifying the role of the reduced metal phases and the acid/basic sites on the main conversion pathways. Both Cu–Al2O3 and Co–Al2O3 catalysts showed a loss of activity after the first run, which can be reversed by a regeneration treatment. The results establish an efficient catalytic route for the production of the diol HCPL (reported for the first time) and the ketone HCPN from bio-derived HMF over 3d transition metals based catalysts in an environmental friendly medium such as water.

22 March 2018 in Angewandte Chemie International Edition
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Alexios GrigoropoulosAlexios Grigoropoulos
Alexios Grigoropoulos
AMAlasdair I. McKay
Alasdair I. McKay
AKAlexandros P. Katsoulidis
Alexandros P. Katsoulidis
RDRobert P. Davies
Robert P. Davies
AHAnthony Haynes
Anthony Haynes
MRMatthew J. Rosseinsky
Matthew J. Rosseinsky
Crabtree's catalyst was encapsulated inside the pores of the sulfonated MIL‐101(Cr) metal–organic framework (MOF) by cation exchange. This hybrid catalyst is active for the heterogeneous hydrogenation of non‐functionalized alkenes either in solution or in the gas phase. Moreover, encapsulation inside a well‐defined hydrophilic microenvironment enhances catalyst stability and selectivity to hydrogenation over isomerization for substrates bearing ligating functionalities. Accordingly, the encapsulated catalyst significantly outperforms its homogeneous counterpart in the hydrogenation of olefinic alcohols in terms of overall conversion and selectivity, with the chemical microenvironment of the MOF host favouring one out of two competing reaction pathways.

8 December 2015 in Chemical Science
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Alexios GrigoropoulosAlexios Grigoropoulos
Alexios Grigoropoulos
GWGeorge F. S. Whitehead
George F. S. Whitehead
NPNoémie Perret
Noémie Perret
AKAlexandros P. Katsoulidis
Alexandros P. Katsoulidis
FCF. Mark Chadwick
F. Mark Chadwick
MRMatthew J. Rosseinsky
Matthew J. Rosseinsky
Metal–Organic Frameworks (MOFs) are porous crystalline materials that have emerged as promising hosts for the heterogenization of homogeneous organometallic catalysts, forming hybrid materials which combine the benefits of both classes of catalysts. Herein, we report the encapsulation of the organometallic cationic Lewis acidic catalyst [CpFe(CO)2(L)]+ ([Fp–L]+, Cp = η5-C5H5, L = weakly bound solvent) inside the pores of the anionic [Et4N]3[In3(BTC)4] MOF (H3BTC = benzenetricarboxylic acid) via a direct one-step cation exchange process. To conclusively validate this methodology, initially [Cp2Co]+ was used as an inert spatial probe to (i) test the stability of the selected host; (ii) monitor the stoichiometry of the cation exchange process and (iii) assess pore dimensions, spatial location of the cationic species and guest-accessible space by single crystal X-ray crystallography. Subsequently, the quasi-isosteric [Fp–L]+ was encapsulated inside the pores via partial cation exchange to form [(Fp–L)0.6(Et4N)2.4][In3(BTC)4]. The latter was rigorously characterized and benchmarked as a heterogeneous catalyst in a simple Diels–Alder reaction, thus verifying the integrity and reactivity of the encapsulated molecular catalyst. These results provide a platform for the development of heterogeneous catalysts with chemically and spatially well-defined catalytic sites by direct exchange of cationic catalysts into anionic MOFs.

2 December 2022 in Polymers
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SMSofia Paraskevi Makri
Sofia Paraskevi Makri
Eleftheria XanthopoulouEleftheria Xanthopoulou
Eleftheria Xanthopoulou
Panagiotis KlonosPanagiotis Klonos
Panagiotis Klonos
Alexios GrigoropoulosAlexios Grigoropoulos
Alexios Grigoropoulos
AKApostolos Kyritsis
Apostolos Kyritsis
Dimitrios BikiarisDimitrios Bikiaris
Dimitrios Bikiaris
Bio-based poly(lactic acid) (PLA) composite films were produced using unmodified soda micro- or nano-lignin as a green filler at four different contents, between 0.5 wt% and 5 wt%. The PLA–lignin composite polymers were synthesized by solvent casting to prepare a masterbatch, followed by melt mixing. The composites were then converted into films, to evaluate the effect of lignin content and size on their physicochemical and mechanical properties. Differential scanning calorimetry (DSC), supported by polarized light microscopy (PLM), infrared spectroscopy (FTIR-ATR), X-ray diffraction (XRD), and transmission electron microscopy (TEM) were employed to investigate the PLA crystallization and the interactions with Lignin (L) and Nanolignin (NL). The presence of both fillers (L and NL) had a negligible effect on the glass transition temperature (chain diffusion). However, it resulted in suppression of the corresponding change in heat capacity. This was indicative of a partial immobilization of the PLA chains on the lignin entities, due to interfacial interactions, which was slightly stronger in the case of NL. Lignin was also found to facilitate crystallization, in terms of nucleation; whereas, this was not clear in the crystalline fraction. The addition of L and NL led to systematically larger crystallites compared with neat PLA, which, combined with the higher melting temperature, provided indications of a denser crystal structure in the composites. The mechanical, optical, antioxidant, and surface properties of the composite films were also investigated. The tensile strength and Young’s modulus were improved by the addition of L and especially NL. The UV-blocking and antioxidant properties of the composite films were also enhanced, especially at higher filler contents. Importantly, the PLA–NL composite films constantly outperformed their PLA–L counterparts, due to the finer dispersion of NL in the PLA matrix, as verified by the TEM micrographs. These results suggest that bio-based and biodegradable PLA films filled with L, and particularly NL, can be employed as competitive and green alternatives in the food packaging industry.