Ionic liquids and deep eutectic solvents for the recovery of phenolic compounds: effect of ionic liquids structure and process parameters

Abstract

Extraction of phenol from aqueous phase to ionic liquid phase.

Influence of Small Quantities of Water on the Physical Properties of Alkylammonium Nitrate Ionic Liquids

“…After a couple of decades of extensive development in the study of the potential uses of ILs, their applications are now a reality in many branches of science and industry. Thus, their uses have been demonstrated in a wide range of areas of analytical chemistry [ 2 ], organic chemistry [ 3 , 4 ], electrochemical conversion and energy storage [ 5 ], biosensing technology [ 6 ], pharmaceutical and biomedical industry [ 7 , 8 ] or recovery of industrial solvents [ 9 , 10 ], to name but a few. In this context, the characterization of these materials through experimental, theoretical or computational methods plays a decisive role to promote their industrial applications [ 11 ].…”

The Pretreatment of Lignocelluloses With Green Solvent as Biorefinery Preprocess: A Minor Review

“…Defined as a new type of solvent, ILs are generally composed of organic cations (imidazolium, piperidinium, ammonium, etc.) and organic or inorganic anions ( Zhang et al, 2012 ; Khan et al, 2021 ), and present as liquid phase at room temperature. Due to its efficiency on selective dissolution of lignin and cellulose ( Muhammad et al, 2015 ; Khan et al, 2016 ; Xu and Wang, 2020 ), renewability, and biodegradability, ILs are widely applied to separate the major components of lignocellulosic biomass ( Kilpeläinen et al, 2007 ; Hou et al, 2012 , 2013 ; Xu et al, 2018 ).…”

“…Due to its efficiency on selective dissolution of lignin and cellulose ( Muhammad et al, 2015 ; Khan et al, 2016 ; Xu and Wang, 2020 ), renewability, and biodegradability, ILs are widely applied to separate the major components of lignocellulosic biomass ( Kilpeläinen et al, 2007 ; Hou et al, 2012 , 2013 ; Xu et al, 2018 ). Compared with ordinary solvents, ILs have the characteristics of being less volatile, and having lower vapor pressure, higher electrochemical stability, and higher thermal stability ( Khan et al, 2021 ). It is worth noting that researchers can design functionalized ionic liquids by the demand of the reaction system to improve its selectivity and efficiency.…”

“…In order to solve the above-mentioned problems for the pretreatment process, deep eutectic solvents (DESs) were developed as a novel environmentally benign solvent with excellent characteristics of both organic solvents and ionic liquids ( Smith et al, 2014 ). DESs are first proposed by Abbott as a versatile alternative to ionic liquids ( Abbott et al, 2004 ), and are usually composed of a certain proportion of hydrogen bond acceptors (HBAs), such as quaternary ammonium salts and betaine, and hydrogen bond donors (HBDs), such as urea, multicomponent alcohol, and carboxylic acid ( Abbott et al, 2001 , 2004 , 2007 ), which present properties, namely, low toxicity and cost, non-volatility, high thermal stability with excellent solubility, and environmental friendliness ( Loow et al, 2017 ; Satlewal et al, 2018 ; Khan et al, 2021 ). The chemical properties of DESs are adjustable, so a targeted DES can be easily synthesized by selecting the appropriate HBD and HBA ( Khan et al, 2021 ).…”

“…DESs are first proposed by Abbott as a versatile alternative to ionic liquids ( Abbott et al, 2004 ), and are usually composed of a certain proportion of hydrogen bond acceptors (HBAs), such as quaternary ammonium salts and betaine, and hydrogen bond donors (HBDs), such as urea, multicomponent alcohol, and carboxylic acid ( Abbott et al, 2001 , 2004 , 2007 ), which present properties, namely, low toxicity and cost, non-volatility, high thermal stability with excellent solubility, and environmental friendliness ( Loow et al, 2017 ; Satlewal et al, 2018 ; Khan et al, 2021 ). The chemical properties of DESs are adjustable, so a targeted DES can be easily synthesized by selecting the appropriate HBD and HBA ( Khan et al, 2021 ). Based on the above-mentioned characteristics, DESs can efficiently remove lignin ( Francisco et al, 2012 ; Zhang et al, 2016a ), dissolve most of hemicellulose ( Xu et al, 2016 ; Yu et al, 2018 ), and, to a large extent, retain cellulose ( Vigier et al, 2015 ; Ren et al, 2016 ), which is beneficial to the selective separation of the three major components of lignocellulosic biomass.…”