Search results for "Salt"

Imidazolium-Functionalized Carbon Nanohorns for the Conversion of CO2 Unprecedented Increase of Catalytic Activity after Recycling

2017

Carbon nanohorns (CNHs) were selected as a novel catalytic platform for the design of imidazolium based hybrid materials able to promote the conversion of carbon dioxide into cyclic carbonates. Several heterogeneous catalysts were prepared using a one-step procedure based on the radical polymerization of various bis-vinylimidazolium salts in the presence of pristine CNHs. The as-synthesized materials were tested for the fixation of CO2 into epoxides. The excellent catalytic performances were evaluated in terms of turnover number and productivity. The versatility of the above hybrids was proved using several epoxides as substrate. Catalysts recyclability was successfully verified for several…

Design of POSS-Imidazolium Supported Hybrids for the Conversion of Carbon Dioxide into Cyclic Carbonates

2018

Nowadays, the design of heterogeneous catalysts for the conversion of CO2 into useful chemical products is attracting the attention of the scientific community. The catalytic processes involving carbon dioxide as C1 feedstock are of growing interest for the sustainable development.1 The synthesis of cyclic carbonates by coupling CO2 with epoxides is one of the most interesting pathways for the conversion of carbon dioxide in terms of both atom economy and final products applications. Moreover, ionic liquids emerged as one of the most active catalysts for the production of cyclic carbonates starting from CO2 and epoxides.2 Herein, a series of heterogeneous catalytic systems bearing imidazoli…

Imidazolium Based Cross-Linked Nanostructures from POSS molecular bricks for the Efficient Conversion of Carbon Dioxide

2019

Polyhedral oligomeric silsesquioxanes (POSS) have been employed as molecular bricks for the synthesis of imidazolium cross-linked networks as heterogeneous catalyst for the conversion of carbon dioxide into cyclic carbonates via reaction with epoxides. Two hybrid materials with different nucleophilic species (bromide and iodide) have been prepared and characterized by means of elemental analysis, 13C and 29Si solid state NMR, thermogravimetric analysis and IR spectroscopy. The solids were tested as the sole catalyst under metal- and solvent-free reaction conditions showing full selectivity toward the formation of cyclic carbonates and outstanding productivity values. Several epoxides were r…

Materiali ibridi a base di POSS-Imidazolio per la conversione della CO2 in carbonati ciclici

2018

Lo sviluppo di catalizzatori per i processi di conversione della CO2 è una tematica che sta rivestendo un ruolo di rilevante importanza in ambito non soltanto accademico ma anche industriale grazie alla possibilità di trasformare un rifiuto, quale il diossido di carbonio, in una vasta gamma di prodotti. Nel presente lavoro, nuovi materiali ibridi costituiti da silsesquiossani poliedrici oligomerici (POSS) supportati su silice e funzionalizzati con sali di imidazolio sono stati progettati per la fissazione della CO2. 1 Tutti i solidi sono stati ampiamente caratterizzati e testati per la sintesi di carbonati ciclici tramite reazione tra CO2 ed epossidi in condizioni di reazione solvent-free (…

Nitrogen-Doped Carbon Nanodots-Ionogels: Preparation, Characterization, and Radical Scavenging Activity

2018

Hybrid diimidazolium-based ionogels were obtained by dispersing nitrogen-doped carbon nanodots (NCNDs) in ionic liquid (IL) solutions and by using dicationic organic salts as gelators. The properties of the NCND-ionogels were studied in terms of thermal stability, mechanical strength, morphology, rheological, and microscopic analyses. Insights into the formation of the hybrid soft material were attained from kinetics of sol-gel phase transition and from estimating the size of the aggregates, obtained from opacity and resonance light-scattering measurements. We demonstrate that, on one hand, NCNDs were able to favor the gel formation both in the presence of gelating and nongelating ILs. On t…

Materiali catalitici a base di nanoparticelle di palladio immobilizzate su nanoforme di carbonio

2019

Aroma and salt release and perception in model cheeses are explained by salt/fat contents, microstructure, salt mobility and oral processing

2013

The health authorities recommend a reduction in salt (NaCl) and fat contents of foodstuff. Reducing such components without affecting acceptability is a major challenge, particularly because of the interactions with other ingredients such as aroma compounds. This study consisted in a multimodal approach to understand the effect of changes in composition of model cheeses on the mobility and release of flavour molecules (NaCl, aroma compounds), masticatory behaviour and flavour perception. Six flavoured model cheeses have been formulated (three fat/protein contents, two NaCl contents). The rheological properties were analysed using uniaxial compression tests. Microstructure and homogeneity we…

Reducing salt and fat while maintaining taste: An approach using cross-modal sensory compensation

2014

Unbalanced diets with an overconsumption of fat, salt and sugars contribute to the development of pathologies. As a consequence, healthcare authorities advocate salt, fat and sugar reduction in food, but this often leads to less tasty products. Several strategies are currently investigated to design healthier food while maintaining taste and consumer liking. The strategy relying on cross-modal sensory compensation is being tested within the framework of the EU-TeRiFiQ research project. The main objective is to evaluate whether an optimisation texture, taste and aroma could help to maintain especially salt or fat perception in low-fat-salt food. Here we set out to examine whether a modificat…

Flavour release and sensory pereption in cheeses

2013

During the eating of food, the in-mouth process leads to food breakdown which induces the release of flavour compounds. Volatile and non-volatile compounds are released into the saliva, and volatile compounds are transferred into the vapour phase to reach olfactory receptors in the nasal cavity. The aim of this chapter is to review the effects of changing the composition of cheeses on the mobility, release and perception of flavour molecules (salt, aroma compounds), and to discuss the results with respect to human physiology. Cheese is a good model because it is possible to vary its composition (in lipids, proteins, salt), in order to comply with nutritional guidelines (less salt, less fat)…

L'intégration multisensorielle comme stratégie pour compenser la réduction en sodium et matière grasse dans les aliments

2015

In recent years;health authorities worldwide advise for a reduction of salt and fat in daily food consumption. However;foods with reduced salt and fat content are often not appreciated by consumers;Therefore;the formulation of low-salt-fat foods that maintain acceptability is a major concern in food research. In this thesis;the multi-sensory integration and release kinetics of flavor compounds were explored as strategies to compensate for salt and fat reduction in cheese products (model cheeses and real cheeses). The objective was to better understand the mechanisms leading to aroma and salt release during mastication and to evaluate how the matrix composition and structure influence salt a…