Green Synthesis of Zeolitic Imidazolate Frameworks: A Review of Their Characterization and Industrial and Medical Applications

Metal organic frameworks (MOF) are a class of hybrid networks of supramolecular solid materials comprising a large number of inorganic and organic linkers, all bound to metal ions in a well-organized fashion. Zeolitic imidazolate frameworks (ZIFs) are a sub-group of MOFs with imidazole as an organic linker to metals; it is rich in carbon, nitrogen, and transition metals. ZIFs combine the classical zeolite characteristics of thermal and chemical stability with pore-size tunability and the rich topological diversity of MOFs. Due to the energy crisis and the existence of organic solvents that lead to environmental hazards, considerable research efforts have been devoted to devising clean and sustainable synthesis routes for ZIFs to reduce the environmental impact of their preparation. Green chemistry is the key to sustainable development, as it will lead to new solutions to existing problems. Moreover, it will present opportunities for new processes and products and, at its heart, is scientific and technological innovation. The green chemistry approach seeks to redesign the materials that make up the basis of our society and our economy, including the materials that generate, store, and transport our energy, in ways that are benign for humans and the environment and that possess intrinsic sustainability. This study covers the principles of green chemistry as used in designing strategies for synthesizing greener, less toxic ZIFs the consume less energy to produce. First, the necessity of green methods in today’s society, their replacement of the usual non-green methods and their benefits are discussed; then, various methods for the green synthesis of ZIF compounds, such as hydrothermally, ionothermally, and by the electrospray technique, are considered. These methods use the least harmful and toxic substances, especially concerning organic solvents, and are also more economical. When a compound is synthesized by a green method, a question arises as to whether these compounds can replace the same compounds as synthesized by non-green methods. For example, is the thermal stability of these compounds (which is one of the most important features of ZIFs) preserved? Therefore, after studying the methods of identifying these compounds, in the last part, there is an in-depth discussion on the various applications of these green-synthesized compounds.

Deep Eutectic Solvents For Efficient Processing of Renewable Resources Into Sustainable Biofuels and High Value-Added Carbon-Based Fine Chemicals: Recent Developments, Challenges, and Future Perspectives

Green chemistry techniques for the exploitation of renewable resources have emerged as beneficial techniques for producing sustainable biofuels and high value-added carbon-based fine chemicals with the potential to decrease the impact of anthropogenic activities on the environment. Despite various green chemistry technologies for processing renewable resources into different valuable products, there are still several major issues concerning the pretreatment processes and techniques, such as high cost and high-energy consumption. Thankfully, deep eutectic solvents (DESs), a potentially attractive “green solvent” biodegradable substitute to environmentally harmful organic solvents, have been progressively exploited for renewable resources processing. Therefore, the central focus of this review is to present recent developments and challenges of DESs as processing green solvents for renewable resources. We believe this comprehensive review will provide new insights towards developing state-of-the-art sustainable and new green technologies for the efficient processing of renewable resources for sustainable biofuels and value-added carbon-based fine chemicals.

A simple setup miniaturization with multiple benefits for Green Chemistry in nanoparticle synthesis

The development of nanomaterials often relies on wet-chemical syntheses performed in reflux-setups using round-bottom-flasks. An alternative approach to synthesize nanomaterials is here presented that uses glass tubes designed for NMR analysis as reactors. This approach uses less solvent, uses less energy, generates less waste, provides safer conditions, is less prone to contamination and is compatible with high throughput screening. The benefits of this approach are illustrated by an in breadth study with the synthesis of gold, iridium, osmium and copper sulfide nanoparticles.