Third Generation Ionic Liquids: Synthesis to Applications

Since the energy and chemical industries have been contributing to environmental pollution for a number of decades, society has come to expect scientists and engineers to try to create sustainable chemical processes that produce fewer harmful substances and more environmentally friendly energy sources. Ionic liquids are becoming more and more well-known in the research industry because of their unique properties and characteristics. Ionic liquids have been applied in both commercial and educational applications. Because of their special thermal, physical, chemical, and biological characteristics, they have the potential to be a clean, efficient, and environmentally friendly alternative source of volatile organic solvents, which could help solve some of the biggest problems society is currently facing. They also have many other important advantages. Furthermore, by changing the ratio of cations to anions, their qualities could change according to how they are used. Thus, a great deal of basic and applied study has focused on them due to their special qualities. Actually, compared to the standard way, ionic liquids are more exciting and effective. As a result, their uses in organic synthesis have expanded greatly because of their increased diversity and adaptability. We have concentrated on the background, properties, and uses of ionic liquids in this book chapter, particularly in the context of organic synthesis. The physicochemical qualities that are important for their usage in industrial applications are therefore measured in a number of ways and reviewed. 

Introducing biological and pharmaceutical perspectives into ionic liquids leads to the formation of a third generation of ionic liquids with lower toxicity and high biodegradability. These 3rd generation ionic liquids overcome the limitations of low thermal stability, solubility, and aggregation often associated with pharmaceutics. In this milieu, the 3rd generation of ionic liquids provides tailor-made biological properties in addition to the conventional ionic liquids (ILs) properties. This chapter provides a concise overview of the basic characterization and a discussion on the extraordinary physicochemical properties of the third generation of ILs/active pharmaceutical ingredients (API)-based ILs in this field. This paper strategically addresses the tuning of molecules to get the desired properties, thermal behavior to determine the transitional of the solid biological component into the liquid, and polymorphism in the field of pharmaceutics. An in-depth view of the nano-structuring phenomena, revealing the insights from structural characterization by NMR and EPR spectroscopy, and also a theoretical understanding of ILs using computational techniques have been discussed. Also, this chapter fosters the understanding of the solubility profiles and surface activity of API-ILs in water to overcome the inadequate biopharmaceutical properties with reference to parent API. This chapter highlights their enhanced biological properties such as antimicrobial, pharmacokinetics, antibacterial activity, etc., and the various literature available on the different API-ILs. This will also include the biomedical perspective, for transport and toxicity studies. The effect of various anions and cations on the various biological and physiochemical properties will be discussed. Overall, the chapter aims to create a comprehensive understanding of the properties and characterization of 3rd generation ILs to pave the way for diverse biological and chemical applications. 

Ionic liquids (ILs) of the third generation have become known to be adaptable substances with prospective applications in numerous scientific domains. They are attractive options for application in catalysis, separations, and energy storage due to their unique physicochemical characteristics, which include low volatility, excellent thermal stability, and variable polarity. The application of ILs as environmentally friendly solvents for chemical reactions, effective electrolytes for batteries, and new materials for the production of nanoparticles are all covered in this chapter. It also emphasizes its potential for environmentally friendly processes and environmental cleanup. In general, third generation integrated light bulbs represent a significant advancement in material science, offering remedies for present challenges in the chemical, energy, and environmental sectors.

In recent years, research in the field of ionic liquids (ILs) has discovered several aspects of their 3rd generation derivatives, such as tuneable physicochemical properties (viscosity, polarity, hydrophobicity), green synthesis, and biocompatibility, making them promising agents in different applications for example clean energy, drug delivery, and other various industrial applications. 3rd Generation ILs have a unique modular architecture that can be modified independently, allowing the design of a range of functional materials while retaining the inherent features of ionic liquids. This chapter explores the application of third-generation ILs in the biomedical and pharmaceutical sectors to solve solubility, polymorphism, and bioavailability challenges. They serve as agents for poorly soluble drugs, modulate polymorphic formations of pharmaceutical compounds, and act as carriers for hydrophobic drugs, respectively. Other applications include drug formulation, delivery, and synthesis owing to their physicochemical properties, which have opened new doors for pharmaceutical research and development. We conclude by exploring the future opportunities that can be realized from integrating ILs into the biomedical and pharmaceutical sectors. 

The pursuit of innovative and unique ionic liquids (ILs) has led to the gradual development and implementation of three generations of ILs. The first generation concentrated mostly on the inherent chemical and physical characteristics of these materials, while the second generation offered the chance to modify these characteristics and create “task-specific ILs,” which can be employed as greener or more ecologically friendly solvents. Utilising the active pharmaceutical ingredients (API) for creating ILs with biological activity, the third and most recent generation of ILs is currently being developed. The incorporation of biomolecules with API-based IL involves the protein stability as well as solubility of the drug molecules. By interacting with biomolecules, ILs can be used for drug delivery, drug carrier, and biomolecular stabilisation applications. To explore the molecular properties of these biomolecular complexes, the combined electronic structure calculations and molecular dynamics simulations are widely used. In this chapter, we intend to explore the molecular-level interaction of this innovative generation of a mixture of ILs/water with biomolecules.

Ionic Liquids have shown new developments in materials chemistry research. ILs combined with polymers allow the development of smart materials and the fabrication of high-performance polymer composites. ILs are formed from different combinations of anions and cations, providing infinite possibilities for tuning their properties. Nanofillers like carbon nanotubes and graphene often need surface modification to improve dispersion in polymer matrices, as they tend to aggregate. ILs can help disperse these fillers by reducing inter-molecular interaction. ILs interact with carbon nanofillers via carbon- π and π-π interactions with the graphitic structures. This builds a strong interface between the filler and polymer. IL applications in polymers are expanding into areas like vulcanization accelerators, dispersants, plasticizers, and modifiers to improve membrane selectivity and electrolytes. Porus polymers with IL monomers may enable new battery/fuel cell membranes, field-responsive gels, etc. Due to the sensitivity of the ionic group to stimuli, polymer-supported ILs show significant early applications in areas like catalysis, nanofluids, and proton conduction. More development is expected around stabilizing dispersions, plasticization, and interpenetrating networks. Solvent-free nanofluids utilizing IL-functionalized surfaces to generate supra-molecular ILs may proliferate. These could produce new resin classes and hybrid materials. Anti-static agents are essential additives for plastics to avoid issues like sparking, dust, buildup, and fire hazards. Anti-static agents work through various mechanisms, allowing flexibility to tune their performance for different applications and meet industry standards. ILs have properties like electric conductivity, viscosity reduction, lubrication, and corrosion inhibition that make them promising anti-static polymer additives. Using lower levels of ionic liquids can minimize costs and environmental impacts while still enhancing polymer properties. Recent literature shows ionic liquids being increasingly utilized in elastomer composites in various roles, including dispersants fillers, crosslinkers, catalysts, and solvents. Their uses will likely continue rising.

The feasibility of using ionic liquids (ILs) in solar thermal power plants as heat transfer fluids (HTFs) and liquid thermal storage media has been investigated. Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), nuclear magnetic resonance (NMR), viscometry, and other pertinent techniques were used to synthesize and thoroughly characterize a number of IL variants, including [C4min][PF6 ], [C8mim][PF6 ], [C4min][bistrifluoromethane sulflonimide], [C4min][BF4 ], and [C4min][bistrifluoromethane sulflonimide]. Important parameters were carefully determined, including density, heat capacity, viscosity, melting point, decomposition temperature, and thermal expansion coefficient. To evaluate the thermophysical properties of basal ILs and nanoparticle-enhanced ILs (NEILs), experiments were carried out. Because solar thermal energy (STE) is more effective than photovoltaic solar cells, energy researchers have been paying close attention to it lately. Heat transfer fluids (HTFs), a secondary medium, are used in STE to transport heat. As such, the thermophysical characteristics and thermal behaviour of the HTFs determine the overall performance of STE systems. High melting point, high decomposition temperature, and high vapor pressure are problems for conventional HTFs. To overcome these constraints, scientists have started working on creating new HTFs specifically designed for STE applications. Because of their improved thermophysical characteristics, such as their strong ionic conductivity, low vapor pressure, and thermal stability at high temperatures, ionic liquids (ILs) have become intriguing candidates for the next generation of HTFs. Moreover, adding nanoparticles to ILs can improve their thermophysical characteristics and thermal performance even more. This is a rapidly developing field of study that aims to increase the effectiveness of solar thermal systems. An overview of recent studies using IL-based nanofluids as HTFs is also given in this study.

Ionic liquids (ILs) have emerged as promising chemical compounds with extensive applications in drug delivery due to their unique and tunable biological and physicochemical properties. Researchers are continually advancing new generations of ILs, and recently, third-generation ILs and Deep Eutectic Solvents (DESs) have exhibited greater efficiency, increased biocompatibility, and enhanced chemical stability compared to their predecessors. This chapter explores the advancements in the generations of ILs followed by DESs and their impacts on enhancing transdermal drug delivery (TDD). TDD is a topic of significant interest in drug delivery due to its potential for directly dosing drugs and other bioactive molecules without invasiveness. Over the past two and a half decades, ILs and DESs have significantly improved TDD by serving as skin permeation enhancers, solvents, and surfactants to regulate skin permeability and pharmacokinetic behavior of drugs and biomaterials. The chapter will focus on highlighting the roles of third generations of ILs and DESs in advancements of TDD.