Investigating the effect of ligand and cation on the properties of metal fluorinated acetylacetonate based magnetic ionic liquids

Magnetic ionic liquids (MILs) are a subclass of ionic liquids that possess a paramagnetic metal within their chemical structure, making them susceptible to external magnetic fields. A total of twenty-four (24) MILs were prepared and characterized to investigate the effect of the ligand, cation and anion on the physiochemical properties of acetylacetonate-based MILs. It was found that thermal stabilities as high as 260 °C could be achieved by incorporating aromatic moieties in the anion structure. Additionally, the magnetic moment could be modulated by simply changing the transition metal in the anion. Magnetic moment values of 2.8 μB, 4.5 μBand 5.6 μB were obtained by using Ni(II), Co(II), and Mn(II) as the metal centers, respectively. Furthermore, the viscosity of the MILs could be tailored from a few hundred centipoise to several thousand centipoise, increasing their potential applications in numerous interdisciplinary fields. Moreover, the MILs synthesized in this study were found to be insoluble in water at a MIL-to-solvent ratio of 0.01% (w/v), making them potentially useful in targeted separations, where very hydrophobic solvents are highly desired

Elucidating the Role of Hydrogen Bond Donor and Acceptor on Solvation in Deep Eutectic Solvents Formed by Ammonium/Phosphonium Salts and Carboxylic Acids

Deep eutectic solvents (DESs) constitute a rapidly emerging class of sustainable liquids that have been widely studied and employed in chemical separations, catalysis, and electrochemistry. The unique physicochemical and solvation properties of DESs can be highly tailored by choosing the appropriate hydrogen bond acceptor (HBA) and hydrogen bond donor (HBD). Understanding the role of the HBA and HBD on the multiple solvation interactions in DESs is important to enable their judicious selection for particular applications. This work constitutes the first study to exploit chromatography to measure solute–solvent interactions of DESs using a wide array of known probe molecules. The constituent components of 20 DESs, formed by ammonium and phosphonium-based salts and carboxylic acids, are systematically modulated to delineate the contribution of the HBA and HBD toward individual solvation properties. Solute–solvent interactions measured in this study are used to interpret and explain the performance of DESs in desulfurization of fuels and extraction of natural products. The results from this study can be used to predict and understand the performance of DESs in various chemical processes where solvation interactions heavily influence outcomes

Ionic liquids and deep eutectic solvents as gas chromatographic stationary phases for separation and characterization

Recent developments have been made to improve the separation of complex molecules. The following chapters describe the optimization and characterization of two unique stationary phases: ionic liquids (ILs) and deep eutectic solvents (DESs). The versatility of ILs have expanded over the years and one of their most interesting applications are their use as gas chromatographic stationary phases. As shown in literature, they can either act as a nonpolar or polar phase depending on the analytes of interest. By manipulating the structure of the ILs, the molecular interactions exhibited between the stationary phase and probes can be tailored for favorable interactions. Imidazolium and phosphonium ILs are commonly used as cations with a variety of different counter anions. One of the major drawbacks of ILs is their low thermal stabilities compared to many other commercial phases. The first study addresses this by incorporating phenyl substituents within the cation to reduce the probability of decomposition pathways. High boiling point analytes such as polycyclic aromatic hydrocarbons (PAHs) and polycyclic biphenyls (PCBs) were separated due to their capability of undergoing π-π interactions with the stationary phase. The second study is also relating to molecular interactions but instead of an IL-based stationary phase, DESs were the materials of interest. Using multiple combinations of hydrogen bond acceptors and donors to form the DESs, in depth molecular insight was gained using inverse gas chromatography (GC). The Abraham solvation parameter model was used to characterize the deep eutectic based stationary phases. As stationary phases, both materials displayed unique interactions where the ILs showed enhanced π-π interactions while the DESs displayed increased hydrogen bond basicity compared to traditional ILs.</p

Ionic liquids and deep eutectic solvents as gas chromatographic stationary phases for separation and characterization

Recent developments have been made to improve the separation of complex molecules. The following chapters describe the optimization and characterization of two unique stationary phases: ionic liquids (ILs) and deep eutectic solvents (DESs). The versatility of ILs have expanded over the years and one of their most interesting applications are their use as gas chromatographic stationary phases. As shown in literature, they can either act as a nonpolar or polar phase depending on the analytes of interest. By manipulating the structure of the ILs, the molecular interactions exhibited between the stationary phase and probes can be tailored for favorable interactions. Imidazolium and phosphonium ILs are commonly used as cations with a variety of different counter anions. One of the major drawbacks of ILs is their low thermal stabilities compared to many other commercial phases. The first study addresses this by incorporating phenyl substituents within the cation to reduce the probability of decomposition pathways. High boiling point analytes such as polycyclic aromatic hydrocarbons (PAHs) and polycyclic biphenyls (PCBs) were separated due to their capability of undergoing π-π interactions with the stationary phase. The second study is also relating to molecular interactions but instead of an IL-based stationary phase, DESs were the materials of interest. Using multiple combinations of hydrogen bond acceptors and donors to form the DESs, in depth molecular insight was gained using inverse gas chromatography (GC). The Abraham solvation parameter model was used to characterize the deep eutectic based stationary phases. As stationary phases, both materials displayed unique interactions where the ILs showed enhanced π-π interactions while the DESs displayed increased hydrogen bond basicity compared to traditional ILs

Elucidating the Role of Hydrogen Bond Donor and Acceptor on Solvation in Deep Eutectic Solvents Formed by Ammonium/Phosphonium Salts and Carboxylic Acids

Deep eutectic solvents (DESs) constitute a rapidly emerging class of sustainable liquids that have been widely studied and employed in chemical separations, catalysis, and electrochemistry. The unique physicochemical and solvation properties of DESs can be highly tailored by choosing the appropriate hydrogen bond acceptor (HBA) and hydrogen bond donor (HBD). Understanding the role of the HBA and HBD on the multiple solvation interactions in DESs is important to enable their judicious selection for particular applications. This work constitutes the first study to exploit chromatography to measure solute–solvent interactions of DESs using a wide array of known probe molecules. The constituent components of 20 DESs, formed by ammonium and phosphonium-based salts and carboxylic acids, are systematically modulated to delineate the contribution of the HBA and HBD toward individual solvation properties. Solute–solvent interactions measured in this study are used to interpret and explain the performance of DESs in desulfurization of fuels and extraction of natural products. The results from this study can be used to predict and understand the performance of DESs in various chemical processes where solvation interactions heavily influence outcomes.</p

Screening Carpet Substrate Interferences in Arson Identification by Solid Phase Microextraction and Gas Chromatography-Mass Spectrometry

The sample analysis and data interpretation is the most challenging step of fire debris analysis, due to the presence of combustion and pyrolysis products in the substrate material. In this study, a headspace solid phase microextraction (HS-SPME) procedure was applied to the extraction of combustion and pyrolysis products from three commonly used carpet substrate materials, made of nylon 6,6 and polyesters. Each carpet sample was burned with and without two different ignitable liquids (ILs), i.e., gasoline and kerosene, and the Total Ion Chromatograms (TICs) and Extracted Ion Profiles of characteristic class compounds of ILs were obtained and compared to those of unburned neat ILs, using gas-chromatography mass spectrometry (GC-MS), to study the possible interferences of these substrate materials in fire debris analysis

Elucidating the Role of Hydrogen Bond Donor and Acceptor on Solvation in Deep Eutectic Solvents Formed by Ammonium/Phosphonium Salts and Carboxylic Acids

Deep eutectic solvents (DESs) constitute a rapidly emerging class of sustainable liquids that have been widely studied and employed in chemical separations, catalysis, and electrochemistry. The unique physicochemical and solvation properties of DESs can be highly tailored by choosing the appropriate hydrogen bond acceptor (HBA) and hydrogen bond donor (HBD). Understanding the role of the HBA and HBD on the multiple solvation interactions in DESs is important to enable their judicious selection for particular applications. This work constitutes the first study to exploit chromatography to measure solute–solvent interactions of DESs using a wide array of known probe molecules. The constituent components of 20 DESs, formed by ammonium and phosphonium-based salts and carboxylic acids, are systematically modulated to delineate the contribution of the HBA and HBD toward individual solvation properties. Solute–solvent interactions measured in this study are used to interpret and explain the performance of DESs in desulfurization of fuels and extraction of natural products. The results from this study can be used to predict and understand the performance of DESs in various chemical processes where solvation interactions heavily influence outcomes.This document is the unedited Author’s version of a Submitted Work that was subsequently accepted for publication in ACS Sustainable Chemistry & Engineering, copyright © American Chemical Society after peer review. To access the final edited and published work see DOI: 10.1021/acssuschemeng.0c06926. Posted with permission.</p

Ultra-high thermal stability perarylated ionic liquids as gas chromatographic stationary phases for the selective separation of polyaromatic hydrocarbons and polychlorinated biphenyls

Ionic liquids (ILs) are well-known in the field of separation science for their unique selectivity when used as stationary phases in gas chromatography (GC). While a significant amount of knowledge has been attained in correlating structural features of an IL to separation selectivity, developments in producing IL-based stationary phases suitable for high temperature GC studies have lagged behind. Column bleed is a result of the stationary phase undergoing volatilization /decomposition at high temperatures and is undesirable in separations coupled to GC/MS. It has been well-known that traditional classes of ILs with long alkyl side chain substituents are susceptible to Hofmann elimination at elevated temperatures. In this study, a new class of IL stationary phases containing perarylated cations exhibiting improved thermal stability are introduced. These ILs were used to prepare wall-coated open tubular columns with high column efficiency and produced very low bleed at temperatures up to 350°C. Their unique chemical structures provide stronger π-π interactions compared to many commercially-available stationary phases. To exploit the unique interactions provided by these stationary phases, the separation of two classes of environmentally hazardous aromatic compounds, namely, polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), was examined. Both classes of compounds contain structural isomers with high boiling points that are often challenging to separate. The perarylated sulfonium and phosphonium IL-based stationary phases exhibited excellent thermal stability as well as unique selectivity toward isomers of PAHs as well as toxic PCB analyte pairs

Investigating the effect of ligand and cation on the properties of metal fluorinated acetylacetonate based magnetic ionic liquids

Magnetic ionic liquids (MILs) are a subclass of ionic liquids that possess a paramagnetic metal within their chemical structure, making them susceptible to external magnetic fields. A total of twenty-four (24) MILs were prepared and characterized to investigate the effect of the ligand, cation and anion on the physiochemical properties of acetylacetonate-based MILs. It was found that thermal stabilities as high as 260 °C could be achieved by incorporating aromatic moieties in the anion structure. Additionally, the magnetic moment could be modulated by simply changing the transition metal in the anion. Magnetic moment values of 2.8 μB, 4.5 μBand 5.6 μB were obtained by using Ni(II), Co(II), and Mn(II) as the metal centers, respectively. Furthermore, the viscosity of the MILs could be tailored from a few hundred centipoise to several thousand centipoise, increasing their potential applications in numerous interdisciplinary fields. Moreover, the MILs synthesized in this study were found to be insoluble in water at a MIL-to-solvent ratio of 0.01% (w/v), making them potentially useful in targeted separations, where very hydrophobic solvents are highly desired.</p