Preface

This book offers a concise description of the application of catalysts for sustainable transformation of the environment in various essential aspects of science and technology. Sustainable green catalytic processes are emerging as the means to empower the existing protocols with a greener, sustainable, and environmentally benign versions that hold enormous potential in industry and academia. Growing international concerns about environmental pollution and global warming have directed the attention of scientists worldwide toward approaches for developing sustainable protocols, and the need for employing greener and more sustainable catalytic approaches that are environmentally greener and more eco-friendly than present ones. Green and sustainable catalysts possess higher selectivity and activity, efficient recovery from the reaction medium, recyclability, and cost-effectiveness, and are prepared using environmentally benign preparation techniques.

The most potent instrument in organic synthesis and the cornerstone of green chemistry is catalysis, which has broadened the possibilities for sustainable, organic transformations in future. The challenges associated with the application of synthetic transformations include the hazardous and cost inefficiency of reaction conditions. Green catalytic conditions, mostly dealing with utilization of safer driven chemical reactions, relax the processes in terms of ambiance and environment. Moreover, the application of photo- and biocatalytic reactions in organic synthesis has received a lot of hype in recent years, with the light-mediated access to bioactive and medicinal compounds along with natural products attracting the focus of the scientific world.

The application in drug derivatization and degradation has explicitly boosted the potency of photo- and biocatalytic processes. The concept of nano photocatalyst for drug-free therapeutics has added a new dimension to the process. The catalyst has played a vital role, from the improvement of reaction conditions to enhanced selectivity of products with a decrease in the creation of byproducts. However, all the catalytic approaches are not always greener. Some employ toxic metals that are not environmentally friendly and are difficult to recycle, which ultimately limits their application on an industrial scale.

The major challenge now is to frame a greener design and development process to create catalysts, and then to use those catalysts in chemical processes that are sustainable. Several catalysts are used in this, including, but not limited to, metal-catalysis, organometallic catalysis, electrocatalysis, photocatalysis, nanocatalysis, biocatalysis, homogeneous and heterogeneous catalysis, and others. Thus, this book highlights the developments made toward designing new catalysts and presents the advancements in the field of chemical synthesis using greener catalytic routes with far-reaching applications.

Chapter 1 focuses on the creation of ecologically friendly chemical processes that depend heavily on green and sustainable catalytic reactions. As the need to lessen the environmental impact of industrial activities becomes more widely acknowledged, catalysis offers a viable solution by permitting effective and selective transformations with less waste creation. The idea of an “atom economy” and the use of renewable feedstock help to further advance sustainability and lessen reliance on fossil fuels. These developments in green catalysis lay the groundwork for the creation of more effective chemical processes that are also cleaner, promoting a more sustainable future.

The second chapter describes various organic transformations that take place in water. Although significant advancements occur every day in the field of green chemistry, there is still much to discover. To attain a sustainable future, there is an urgent requirement to focus on the development of diverse, eco-friendly protocols, especially those which can be carried out in H2O. Enzyme catalysis needs to be explored extensively as well.

Chapter 3 is about the Reversible Addition-Fragmentation Chain Transfer (RAFT) polymerization, which operates through the reversible deactivation of radicals using special transfer agents. Photocatalysts in atom transfer radical polymerization (ATRP) have been found to mitigate downsides, such as biocidal UV light, low oxygen tolerance, and applicability to limited monomers.

The RAFT technique has been integrated with photooxidation/reduction catalytic reaction, where the modification has benefited in terms of low energy consumption, mild reaction condition, controllability, and high tolerance towards oxidation. Also note that while the inclusion of organic or inorganic photo redox catalysts to enhance the oxygen-tolerance of RAFT polymerization has been widely accepted, a metal-free approach has been additionally developed which is considered “greener”. Further, the sustainability of the RAFT polymerization technique has been improved by expanding its applicability to design bio-renewable plastics.

Chapter 4 evaluates new approaches like C-H bond activation, photoredox catalysis, borrowed hydrogen catalysis, selective (stereo- and regio-) syntheses, as well as other novel, inventive general protocols for the synthesis and functionalization of heterocyclic compounds that have greatly aided in drug discovery and pharmaceutical research. Therefore, this chapter provides an overview of several cutting-edge heterocyclic synthesis techniques currently used in the field of drug development and medicinal chemistry.

The study of asymmetric organo-catalysis is currently quite popular. Numerous appealing characteristics exist in it, including new forms of activation, gentle reaction conditions, and processes free of transition metals. These organo-catalysts more effectively uphold the sustainability and green chemistry principles. Asymmetric organocatalytic synthesis of enantioenriched profens has made amazing progress, although it has yet to reach its full potential. Thus, the fifth chapter discusses the future advancements in the synthesis of profens and how their derivatives are expected to significantly aid further research into innovative organo-catalyst systems that require reduced catalytic loadings.

Chapter 6 discusses the advancements made in recent years for the greener synthesis of chemical compounds using nanocatalysts. The chapter focuses on three major ideas that are considered important in the green synthesis of chemical compounds: (i) synthesis of green nanocatalysts; (ii) greener reaction conditions; and (iii) the use of green nanocatalyst along with greener reaction conditions.

The seventh chapter frames the recent advances in heterogeneous photocatalysis and its applications. It delves into the fundamental principles that underpin photocatalysis, encompassing a comprehensive examination of photocatalyst categories, the mechanisms governing photocatalysis, and the factors that influence its efficiency. Subsequently, this section explores the diverse applications of heterogeneous photocatalysis, spanning pollutant degradation, CO2 reduction, water splitting, and organic synthesis. The mechanisms and challenges associated with each application are discussed, along with recent advances in enhancing the photocatalytic performance of catalysts.

The chapter also presents the future directions and challenges in heterogeneous photocatalysis, which include the development of more efficient and stable catalysts, exploring new photocatalytic reactions, optimizing reaction conditions, and highlighting the importance of heterogeneous photocatalysis in addressing global environmental and energy challenges.

Briefly put, compared to traditional chemical processes, biocatalytic processes are more cost- and environmentally friendly, as well as sustainable. By applying the ideas of biochemistry, chemical science may solve the energy crisis, make industrial production infinitely more efficient, and provide mankind with wings.

Chapter 8 emphasizes the applications and improved properties of the nanostructures obtained using green synthesis, while Chapter 9 explores the mechanisms underlying the total synthesis and functionalization of natural products with light-driven reactions. This section explores the important phtoredox catalysis process, which is used extensively for the total synthesis of natural products of their functionalization. Because, the utility of natural products has been expanding their application in several fields like human and veterinary medicine, agriculture, the food and cosmetic industries, etc. The widespread application of visible-light-mediated photocatalysis is evolving as a new chemical tool for various C-C bond formation reactions.

Upcoming directions could include the increased use of these photocatalytic approaches due to its atom economical, green, and efficient characteristics. The introduction of “Green Metrics” has played a pivotal role, underscoring their critical contribution to advancing sustainable development. The tenth chapter introduces numerous metrics from across different fields, many have seen limited use for specific, one-time purposes.

Chapter 11 discusses the bio-based economy as the best approach to converting waste biomass, similar to how agricultural forestry by-products and food supply chain waste convert into liquid fuels, common chemicals, and biopolymers. Carbon-based nanocomposites are used as bio-catalysis, which are environmentally friendly.

Every technology’s success is determined by its accessibility of use and economic feasibility. This is the first evaluation of its sort to shed...