Search results for "liquids"

Direct experimental observation of mesoscopic fluorous domains in fluorinated room temperature ionic liquids

2017

Fluorinated room temperature ionic liquids (FRTILs) represent a class of solvent media that are attracting great attention due to their IL-specific properties as well as features stemming from their fluorous nature. Medium-to-long fluorous tails constitute a well-defined apolar moiety in the otherwise polar environment. Similarly to the case of alkyl tails, such chains are expected to result in the formation of self-assembled fluorous domains. So far, however, no direct experimental observation has been made of the existence of such structural heterogeneities on the nm scale. We report here the first experimental evidence of the existence of mesoscopic spatial segregation of fluorinated dom…

Stability and nature of the volume collapse of ε-FeO under extreme conditions

2018

Iron oxides are among the major constituents of the deep Earth's interior. Among them, the epsilon phase of FeO is one of the less studied polymorphs and there is a lack of information about its structural, electronic and magnetic transformations at extreme conditions. Here we report the precise determination of its equation of state and a deep analysis of the evolution of the polyhedral units under compression, thanks to the agreement between our experiments and ab-initio simulations. Our results indicate that this material, with remarkable magnetic properties, is stable at pressures up to 27 GPa. Above 27 GPa, a volume collapse has been observed and ascribed to a change of the local envir…

Chemo-enzymatic Conversion of Glucose in 5-Hydroxymethylfurfural: The Joint Effect of Ionic Liquids and Ultrasound

2020

For the valorization of lignocellulosic biomass, a key step is unlocking the conversion of glucose to suitable chemical platforms. To this aim, we herein describe the sequential chemo-enzymatic conversion of glucose into 5-hydroxymethylfurfural (5-HMF), in two steps: glucose isomerization to fructose, catalyzed by glucose isomerase (GI) and fructose dehydration to 5-HMF promoted by Amberlyst 15. The novelty of our approach lies in the use of crude cell extracts of Streptomyces coelicolor showing GI activity, as isomerization catalysts, along with a commercial immobilized GI. Under optimized reaction conditions, we obtained a conversion to 5-HMF (C5‑HMF) from glucose of 50% in the H2O/[bmim]…

DEEP EUTECTIC SOLVENTS E LIQUIDI IONICI: SOLVENTI PER LO SVILUPPO DI PROCESSI ECO-COMPATIBILI

2020

L’obiettivo di questi tre anni di Dottorato è stato lo studio e l’utilizzo nuovi solventi di reazione in grado di sostituire i solventi organici classici. In particolare sono stati studiati i Deep Eutectic Solvent (DES) e le miscele di Liquidi Ionici (IL). I DES sono stati utilizzati come solventi per lo studio di reazioni organiche, usate per la formazione di nuovi legami C-C. Nello specifico sono state studiate la reazione di Diels-Alder, e diverse reazioni di coupling C-C catalizzate da Pd. In seguito, i DES sono stati utilizzati per la formazione di nuovi gel supramolecolari, chiamati eutectogel. Questi gel sono stati formati usando come gelator amminoacidi naturali, consentendo quindi …

Cross-Linked Polyamine from Imidazolium-Based Materials: A Simple Route to Useful Catalytic Materials

2018

Cross-linked polyamine-based materials were easily prepared by reduction of the corresponding cross-linked imidazolium-based materials with sodium borohydride in hot ethanol. Overall, the synthetic procedure is based on the polymerization of a suitable bis-vinylimidazolium salt with or without a suitable support, such as silica or silica-coated magnetic nanoparticles (γ-Fe2O3@SiO2), followed by reduction. This simple approach allows the synthesis of materials based on a network of secondary and tertiary amines. Materials were characterized by13C cross-polarization magic angle spinning NMR (13C CPMAS NMR), proton spin-lattice relaxation times in the rotating frame (T1ρH) and thermogravimet…

Hybrid ionogels as potential antioxidant agents

In the present study, the influence of CNTs on the gelling ability of some carboxylate imidazolium gelators in ionic liquid solutions has been investigated.

Bio-based 1,3-diisobutyl imidazolium hydrogen oxalate [iBu 2 IM](HC 2 O 4 ) as CO 2 shuttle

2017

International audience; This manuscript describes the using of biosourced L-valine, oxalic acid and glyoxal to produce a biobased imidazolium hydrogen oxalate [iBu(2)IM](HC2O4) which is converted to its related hydrogen carbonate salt by a simple electrolysis without using strong base. The addition of weak protic acids to the latter compound leads to a rapid and quantitative CO2 release with formation of the starting hydrogen oxalate salt or a new halide free bio-based ionic liquid [iBu(2)IM](AcO) which is able to adsorb reversibly the CO2 at room temperature. The protonation reactions, combined with electrolysis, could then be a promising alternative solution for storage and transport of C…

Alkylation of ambident indole anion in ionic liquids

2007

AbstractAlkylation of indole salts in different ionic liquids is reported. Ionic liquids increase the alkylation reaction rate of ambident indole anion and reduce the effects of counter ions and/or additives, the alkylation reaction rates being independent of the presence of small amounts of protic solvents or water.

Estimation of Solute-Stationary Phase and Solute-Mobile Phase Interactions in the Presence of Ionic Liquids

2019

The presence of free silanols on alkyl-bonded reversed-phase stationary phases is responsible for broad and asymmetrical peaks when basic drugs are chromatographed with conventional octadecylsilane (C18) columns due to ionic interactions. In the last few years, ionic liquids (ILs) have attracted attention to reduce this undesirable silanol activity. ILs should be considered as dual modifiers (with a cationic and anionic character), which means that both cations and anions are able to adsorb on the stationary phase, creating a positively or negatively charged layer, depending on the relative adsorption. The accessibility of basic compounds to the silanols is prevented by both the IL cation a…

Ionic liquid crystals based on 3-perfluoalkyl-1,2,4-triazol-4-ium salts

2016

Liquid-crystalline ionic liquids (LC-ILs) are a class of organic materials that of great current interest: they are defined as organic salts that possess the properties of two interesting kinds of material – ionic liquids (ILs) and liquid crystals (LCs). LC-ILs combine many interesting features of ILs (e.g. low volatility and the ability to dissolve solutes with a range of polarities) as well as many attractive properties of LCs (e.g. their intrinsic order and anisotropy). This provides unique opportunities that can be exploited in many different fields, for example their use as solvents for extraction processes as well as electrolytes for batteries, fuel cells, and dye-sensitised solar cel…