Search results for "deep eutectic solvent"

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 …

Activity of a Heterogeneous Catalyst in Deep Eutectic Solvents: The Case of Carbohydrate Conversion into 5-Hydroxymethylfurfural

2019

Obtaining industrially relevant products from renewable resources and developing processes under the light of sustainable chemistry is a prominent endeavor of present-day chemical research. In this context, herein we investigated the dehydration of fructose and sucrose in deep eutectic solvents promoted by the ion-exchange resin Amberlyst 15 as heterogeneous catalyst. We optimized the reaction conditions in terms of temperature, catalyst loading, and initial amount of substrate. Then, we looked at the effect of structural variations in the solvent components on the reaction outcome. Under the best experimental conditions, we obtained very good yields of 78% at 60 °C and 69% at 80 °C for fru…

Use of green alternative solvents in dispersive liquid‐liquid microextraction: A review

2021

Dispersive liquid-liquid microextraction is one of the most widely used microextraction techniques currently in the Analytical Chemistry field, mainly due to its simplicity and rapidity. The operational mode of this approach has been constantly changing since its introduction, adapting to new trends and applications. Most of these changes are related to the nature of the solvent employed for the microextraction. From the classical halogenated solvents (e.g., chloroform or dichloromethane), different alternatives have been proposed in order to obtain safer and non-pollutants microextraction applications. In this sense, low density solvents, such as alkanols, switchable hydrophobicity solvent…

Liquid structure and dynamics in the choline acetate:urea 1:2 deep eutectic solvent

2021

We report on the thermodynamic, structural, and dynamic properties of a recently proposed deep eutectic solvent, formed by choline acetate (ChAc) and urea (U) at the stoichiometric ratio 1:2, hereinafter indicated as ChAc:U. Although the crystalline phase melts at 36-38 degrees C depending on the heating rate, ChAc:U can be easily supercooled at sub-ambient conditions, thus maintaining at the liquid state, with a glass-liquid transition at about -50 degrees C. Synchrotron high energy x-ray scattering experiments provide the experimental data for supporting a reverse Monte Carlo analysis to extract structural information at the atomistic level. This exploration of the liquid structure of ChA…

Systematic Synthesis and Properties Evaluation of Dicationic Ionic Liquids, and a Glance Into a Potential New Field

2018

Dicationic ionic liquids (DILs), a subset of the ionic liquid (IL) family, have attracted growing interest in recent years, and the range of applications within which they are investigated is constantly expanding. However, data which allows structure to property correlation of a DIL is still limited, and thus selecting an appropriate salt to address a specific challenge can be problematic. In comparison to traditional ILs, DILs physico-chemical properties can be tuned by changing the length and type of spacer which connects the cationic heads as well as the type of cation. This in turn could give rise to symmetrical or asymmetrical DILs. In this work, a systematic study of a homogeneous cla…

An ultrasonic-assisted process for copper recovery in a des solvent: Leaching and re-deposition

2017

Abstract The continuous growth of the electronic equipment market has led to an increased amount of scraping that it becomes necessary to recover. A hydrometallurgical method for copper and precious metal recovery from e-waste must consist of a number of steps: leaching, ion separation and subsequent electrochemical re-deposition of the target metal. Although this task is achievable in aqueous solutions, it requires strong acid or cyanide solutions. The aim of the study is to develop a new environmentally benign process by using a Deep Eutectic Solvent (DES), a form of cheap and safe ionic liquid, as an electrolyte for both leaching and electrodeposition. The experiments were conducted in a…

Iodocyclization of 2-Methylthiophenylacetylenes to 3-Iodobenzothiophenes and their coupling Reactions under More Sustainable Conditions

2022

We report the first example of iodocyclization of readily available 2-methylthiophenylacetylenes in a deep eutectic solvent (ChCl/urea 1/2, mol/mol) as recyclable and more sustainable solvent with respect to the classical VOCs employed so far. The process successfully afforded a variety of 3-iodobenzothiophenes in good to high yields starting from differently substituted substrates, with the possibility to recycle the DES several times without appreciable lowering of the product yield. The 3-iodothiophenes thus synthesized are known to be important precursors of biologically active molecules and functionalized heterocycles, and were successfully employed for performing representative Sonoga…

Eutectogel: materiali per il risanamento ambientale

2019

Eutectogels: Materials for Environmental Recovery

Polysaccharide-based supramolecular bicomponent eutectogels as sustainable antioxidant materials

2023

In this work, we obtained supramolecular gels in deep eutectic solvents (DES) from polysaccharides like chitosan and chitosan : cellulose composites. We thoroughly characterized our gels by determining the minimum gelation concentration, as well as their porosity and swelling. We also investigated their mechanical properties by rheology, and morphology by scanning electron measurements. These properties were mainly influenced by the number of hydrogen bond sites on the hydrogen bond donor, (HBD), while FTIR-ATR investigation suggested that, upon gelation, cholinium cations interpose between polysaccharide chains affecting interchain hydrogen bonding. Our gels also exhibited self-healing and…