Search results for "Catalytic"

The influence of ultrasound on the RuI3-catalyzed oxidation of phenol: Catalyst study and experimental design

2009

Abstract The influence of ultrasound at 24 kHz on the heterogeneous aqueous oxidation of phenol over RuI3 with hydrogen peroxide (H2O2) was studied isothermally at 298 K. Effect of ultrasound irradiation on catalytic properties and performance of RuI3 has been studied in details by means of scanning electron microscopy (SEM), X-ray powder diffraction (XRD), dispersion analyzer and a surface analyzer. Turn over frequency of the catalyst was also calculated. In this work, experimental design methodology was applied to optimize the degradation of phenol in aqueous solution, while minimizing an excessive consumption of chemical reagents. The independent variables considered were the catalyst lo…

Development of Eco-Friendly and Self-Cleaning Lime-Pozzolan Plasters for Bio-Construction and Cultural Heritage

2020

Summarization: Nowadays, the design and use of multi-functional mortars has increased significantly, with interesting applications in the green building and cultural heritage conservation sectors. A key point for a correct adoption of these innovative materials is their behavior along time and their resistance to the weathering. The objective of this project was to define the performance and durability of innovative mortars, in order to use them correctly and to avoid irreparable damage over time. For the development of this project, lime–metakaolin and hydraulic lime–metakaolin based mortars (hereinafter called A, B), as well as A and B with the addition of nano-TiO2 and perlite (hereinaft…

Comparison between catalytic and catalytic photo-assisted propene hydration by using supported heteropolyacid

2012

Abstract Hybrid materials have been prepared by impregnation of the heteropolyacid H 3 PW 12 O 40 on commercial TiO 2 . The polyoxometalates (POM) amount deposited was 15, 30, 50 and 70% with respect to the weight of the TiO 2 support. Moreover two samples containing a POM amount of 15, and 50% with respect to the weight of SiO 2 were also prepared for the sake of comparison. All prepared samples were efficient catalysts for the hydration of propene to 2-propanol in gas–solid regime at atmospheric pressure and at temperatures ranging between 50 and 85 °C. The study carried out on the hybrid TiO 2 based materials evidenced that, as far as the catalytic activity is concerned, exists an optimu…

Über die autoxydation ungesättigter verbindungen. III. Mit. Die katalyse der autoxydation des linolsäuremethylesters durch metallverbindungen und dur…

1955

Es wird die Katalyse der Autoxydation des Linolsauremethylesters durch Metallverbindungen und durch verschiedene kombinierte Katalysatorsysteme untersucht. Bei der metallkatalysierten Autoxydation werden die zugesetzten Metallverbindungen nur in Verbindung mit dem entstehenden Substratperoxyd wirksam; ihre katalytische Wirkung beruht auf einer Aktivierung des radikalischen Zerfalls des Substratsperoxydes und der damit verbundenen Steigerung der Autokatalyse der Autoxydation. Weiterhin ergibt sich, das nur Peroxyde mit einer Hydroperoxy-Gruppe allein durch Metallverbindungen vom Typ des Cu++-Oktoates aktivierbar sind, nicht dagegen Dialkylperoxyde und Diacylperoxyde. Der Mechanismus der Pero…

CoOx catalysts supported on alumina and alumina-baria: influence of the support on the cobalt species and their activity in NO reduction by C3H6 in l…

2003

Abstract CoO x catalysts (Co 1 and 3 wt.%) were prepared by incipient-wetness impregnation of the supports, Al 2 O 3 and Al 2 O 3 (80 wt.%)-BaO (20 wt.%), and calcined at 500 and 800 °C. The samples were characterized by X-ray diffraction (XRD) and BET techniques. H 2 -temperature programmed reduction (TPR) and UV-Vis diffuse reflectance spectroscopy (DRS) spectra were recorded with the aim to identify the different Co species formed. The presence of Co 2+ species tetrahedrally and octahedrally coordinated appears strongly influenced by the nature of the support and the cobalt content. Co 3 O 4 particles were detected after calcination at 500 °C, a successive treatment at 800 °C promotes th…

Drug Screening Boosted by Hyperpolarized Long-Lived States in NMR

2014

International audience; : Transverse and longitudinal relaxation times (T1ρ and T1 ) have been widely exploited in NMR to probe the binding of ligands and putative drugs to target proteins. We have shown recently that long-lived states (LLS) can be more sensitive to ligand binding. LLS can be excited if the ligand comprises at least two coupled spins. Herein we broaden the scope of ligand screening by LLS to arbitrary ligands by covalent attachment of a functional group, which comprises a pair of coupled protons that are isolated from neighboring magnetic nuclei. The resulting functionalized ligands have longitudinal relaxation times T1 ((1) H) that are sufficiently long to allow the powerf…

Combination of ozonation and photocatalysis for purification of aqueous effluents containing formic acid as probe pollutant and bromide ion

2014

The treatment by advanced oxidation processes (AOPs) of waters contaminated by organic pollutants and containing also innocuous bromide ions may generate bromate ions as a co-product. In the present work heterogeneous photocatalysis and ozonation have individually been applied and in combination (integrated process) to degrade the organic compounds in water containing also bromide anions. The results show that: i) the sole photocatalysis does not produce bromate ions and in the case of its presence, it is able to reduce bromate to innocuous bromide ions; ii) the integration of photocatalysis and ozonation synergistically enhances the oxidation capabilities; and iii) in the integrated proces…

Brønsted and Lewis acid catalyzed conversion of pulp industry waste biomass to levulinic acid

2019

Enormous amounts of fiber sludge are generated annually by the pulp industry as a by-product. As a cellulose-rich material, its current usage, mainly as fuel, is inefficient from a material efficiency point of view. This work studied the utilization of fiber sludge from a Finnish and a Swedish pulp mill as a potential feedstock to produce levulinic acid, a valuable platform chemical. The conversion experiments of fiber sludge to levulinic acid were performed in a microwave reactor with a mixture of H2SO4 and Lewis acid as the catalyst. The reaction conditions, which included reaction time and temperature as well as the H2SO4 and Lewis acid concentrations, were studied in detail. The highest…

Graphitic C3N4 for CO2 reduction: a photoactivity and stability study

Generation of human pulmonary microvascular endothelial cell lines.

2001

The limited lifespan of human microvascular endothelial cells in cell culture represents a major obstacle for the study of microvascular pathobiology. To date, no endothelial cell line is available that demonstrates all of the fundamental characteristics of microvascular endothelial cells. We have generated endothelial cell lines from human pulmonary microvascular endothelial cells (HPMEC) isolated from adult donors. HPMEC were cotransfected with a plasmid encoding the catalytic component of telomerase (hTERT) and a plasmid encoding the simian virus 40 (SV40) large T antigen. Cells transfected with either plasmid alone had an extended lifespan, but the cultures eventually entered crisis aft…