1,721,049 research outputs found
Transport properties of small penetrants in the crystalline phase of syndiotactic polystirene: simulations and experiments
No full textSorption of chlorinated solvents and their mixtures in semicrystalline syndiotactic polystyrene: role of adsorption in the crystalline phase atti AlChE Meeting
No full textMonolithic Porous Organic Polymer-Photocatalyst Composites for Applications in Catalysis
No full textThis Review provides a perspective on porous organic polymer-photocatalyst composites obtained by coupling semiconductors and hydrophilic/hydrophobic polymers which do not modify the properties of the embedded photocatalysts, but can influence the efficiency of the overall catalytic process. Particular attention has been given to polymer composites in the form of monolithic hydrogel/sponge/aerogels obtained by dissolving the polymer in a solvent, which contains the photocatalyst dispersed, inducing gelation or solidification of the solution and subsequently removing the solvent by a drying process. The photocatalytic applications discussed here cover H-2 evolution from water splitting, CO2 reduction, and organic synthesis. Indeed, the main aim of this Review is to outline an alternative perspective to the highly studied environmental photocatalytic applications, highlighting the photoactive properties of these composites thanks to the incorporation of semiconductors in the 3D porous structure of organic polymers. Finally the challenges and potential advances associated with the use of porous organic polymer-photocatalyst composites for future scientific research are outlined
Selective Photocatalytic Reduction of Nitrobenzene to Aniline Using TiO2 Embedded in sPS Aerogel
No full textIn recent years, aromatic substances have become the focus of environmental pollution-related concern due to their high stability and mutagenicity. In this regard, researchers have focused their attention on the development of photocatalytic processes to convert nitroaromatic compounds into aniline. In this work, the photocatalytic conversion of nitrobenzene (NB) to aniline (AN) was studied. The photocatalytic reaction was performed using commercial TiO2 (P25) and a photocatalytic aerogel, based on P25 embedded in syndiotactic polystyrene (sPS) aerogel (sPS/P25 aerogel) as photocatalysts. Different alcohols were used as hydrogen sources during the photocatalytic experiments. At the optimized operating conditions (photocatalysts dosage: 0.5 mg/L and 50% (v/v) EtOH%), an AN yield of over 99% was achieved. According to the results, this work could open avenues toward effective production of AN from NB using mild reaction conditions with sPS/P25 aerogel-in view of a possible scale-up of the photocatalytic process
Aluminium complexes of salanol ligands: coordination chemistry and stereoselective lactide polymerization
No full textThe tetradentate dianionic {ONNO}-type salanol ligands featuring phenolate and alcoholate arms and a chiral-bipyrrolidine core are introduced. The diastereoselectively-formed {ONNO}-Al-OBn complexes catalyze the ring-opening polymerization of rac-lactide and meso-lactide by either the dual stereocontrol or the chain-end stereocontrol mechanisms to give PLAs of all possible tacticities. This journal i
Isoselective Polymerization of rac-Lactide by Highly Active Sequential {ONNN} Magnesium Complexes
No full textThe coordination chemistry and the activities in the ring-opening polymerization catalysis of racemic lactide (LA) of magnesium complexes of a series of {ONNN}-type sequential monoanionic ligands are described. All ligands include pyridyl and substituted-phenolate as peripheral groups. The ligands bearing either chiral or meso-bipyrrolidine cores led to single diastereomeric complexes, whereas the ligands bearing a diaminoethane core led to diastereomer mixtures. All {ONNN}Mg-X complexes [X=Cl, HMDS (hexamethyldisilazide)] led to highly active and isoselective catalysts. The complexes bearing the chiral bipyrrolidine core exhibited the highest activities (full consumption of 5000 equiv. of rac-LA at RT within 5 min) and highest isoselectivities (Pm=0.91), as well as a living character. The complexes of the meso-bipyrrolidine based ligands were almost as active and slightly less stereoselective, while those of the diaminoethane based ligands exhibited reduced activities and isoselectivities
- …
