Aqueous Microwave Assisted Chemistry: Synthesis and Catalysis (RSC Green Chemistry, 7) - Hardcover

Hardcover

ISBN 10: 1849730385 ISBN 13: 9781849730389

Verlag: Royal Society of Chemistry, 2010

Inhaltsangabe

The demands for green and sustainable synthetic methods in the fields of healthcare and fine chemicals, combined with the pressure to produce these substances expeditiously and in an environmentally benign fashion, pose significant challenges to the synthetic chemical community. Green chemistry can avoid pollution by utilizing techniques that are environmentally friendly by design and one of the best green techniques is the use of microwave (MW) assisted aqueous synthetic protocols. Fusing MW technique with water (as a benign reaction medium) can offer an extraordinary synergistic effect with greater potential than these two individual components in isolation. Selective microwave heating can be exploited to develop a high yield protocol and the use of water expedites the MW-protocol with more energy efficiency. This book provides an overview of the various processes developed using aqueous microwave chemistry and is written for chemists, chemical engineers and researchers in the early stages who want to develop sustainable and green processes. Written by well known microwave experts, the book is a comprehensive examination of the field and is the first book that deals strictly with aqueous microwave chemistry and represents a significant effort towards green chemistry. It covers all the microwave-assisted aqueous reactions in depth, including heterocycle synthesis, metal catalysis, enzyme catalysis, polymer synthesis, nanomaterials synthesis and nano-catalysis. Each chapter contains representative experimental procedures, helping the reader quickly replicate some of the experiments to gain hands-on experience.

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Über die Autorinnen und Autoren

Dr Vivek Polshettiwar was born in Mangli (India) in 1979. He obtained his Ph.D. (2005) under the supervision of Prof. M. P. Kaushik from Jiwaji University and DRDE, Gwalior. He investigated nanostructured silica-catalysis, with Prof. J. J. E. Moreau and Prof. P. Hesemann in 2006 during his postdoctoral research at ENSCM, Montpellier (France). He also worked as project leader in Jubilant Chemsys, Noida for short time.. Then he moved to the U. S. Environmental Protection Agency (2007-2009) to research nano-catalysis and MW-assisted new synthetic methods for green chemistry with Prof. R. S. Varma. Currently, he is working as senior research scientist at KAUST catalysis center directed by Prof. J. M. Basset. His research interests are in the area of advanced nano-materials for perfect catalysis. He has over 50 publications including various review articles and book chapters. Prof. Rajender S. Varma was born in India (Ph.D., Delhi University 1976). After postdoctoral research at Robert Robinson Laboratories, Liverpool, UK, he was a faculty member at Baylor College of Medicine and Sam Houston State University prior to joining the US Environmental Protection Agency in 1999. He has over 35 years of research experience in management of multi-disciplinary programs that include nanomaterials and development of environmentally friendlier alternatives for synthetic methods using microwaves, and ultrasound etc. He has published over 300 scientific papers and has been awarded 6 US Patents.

Dr Vivek Polshettiwar was born in Mangli (India) in 1979. He obtained his Ph.D. (2005) under the supervision of Prof. M. P. Kaushik from Jiwaji University and DRDE, Gwalior. He investigated nanostructured silica-catalysis, with Prof. J. J. E. Moreau and Prof. P. Hesemann in 2006 during his postdoctoral research at ENSCM, Montpellier (France). He also worked as project leader in Jubilant Chemsys, Noida for short time.. Then he moved to the U. S. Environmental Protection Agency (2007-2009) to research nano-catalysis and MW-assisted new synthetic methods for green chemistry with Prof. R. S. Varma. Currently, he is working as senior research scientist at KAUST catalysis center directed by Prof. J. M. Basset. His research interests are in the area of advanced nano-materials for perfect catalysis. He has over 50 publications including various review articles and book chapters. Prof. Rajender S. Varma was born in India (Ph.D., Delhi University 1976). After postdoctoral research at Robert Robinson Laboratories, Liverpool, UK, he was a faculty member at Baylor College of Medicine and Sam Houston State University prior to joining the US Environmental Protection Agency in 1999. He has over 35 years of research experience in management of multi-disciplinary programs that include nanomaterials and development of environmentally friendlier alternatives for synthetic methods using microwaves, and ultrasound etc. He has published over 300 scientific papers and has been awarded 6 US Patents.

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The demands for green and sustainable synthetic methods in the fields of healthcare and fine chemicals, combined with the pressure to produce these substances expeditiously and in an environmentally benign fashion, pose significant challenges to the synthetic chemical community. Green chemistry can avoid pollution by utilizing techniques that are environmentally friendly by design and one of the best green techniques is the use of microwave (MW) assisted aqueous synthetic protocols. Fusing MW technique with water (as a benign reaction medium) can offer an extraordinary synergistic effect with greater potential than these two individual components in isolation. Selective microwave heating can be exploited to develop a high yield protocol and the use of water expedites the MW-protocol with more energy efficiency. This book provides an overview of the various processes developed using aqueous microwave chemistry and is written for chemists, chemical engineers and researchers in the early stages who want to develop sustainable and green processes. Written by well known microwave experts, the book is a comprehensive examination of the field and is the first book that deals strictly with aqueous microwave chemistry and represents a significant effort towards green chemistry. It covers all the microwave-assisted aqueous reactions in depth, including heterocycle synthesis, metal catalysis, enzyme catalysis, polymer synthesis, nanomaterials synthesis and nano-catalysis. Each chapter contains representative experimental procedures, helping the reader quickly replicate some of the experiments to gain hands-on experience.

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Aqueous Microwave Assisted Chemistry

Synthesis and Catalysis

By Vivek Polshettiwar, Rajender S. Varma

The Royal Society of Chemistry

Copyright © 2010 The Royal Society of Chemistry
All rights reserved.

ISBN: 978-1-84973-038-9

Contents

About the Authors, xii, 
Chapter 1 Fundamentals of Aqueous Microwave Chemistry Vivek Polshettiwar and Rajender S. Varma, 1, 
Chapter 2 Metal-catalyzed Reactions in Water under MW Irradiation Victorio Cadierno, Pascale Crochet and Sergio E. García-Garrido, 10, 
Chapter 3 Microwave-assisted Coupling Reactions in Aqueous Media Aziz Fihri and Christophe Len, 55, 
Chapter 4 Microwave-assisted Synthesis of Bio-active Heterocycles in Aqueous Media Vivek Polshettiwar and Rajender S. Varma, 91, 
Chapter 5 Microwave-assisted Enzymatic Reactions in Aqueous Media Hua Zhao, 123, 
Chapter 6 Microwave-assisted Synthesis of Polymers in Aqueous Media Catherine Marestin and Régis Mercier, 145, 
Chapter 7 Microwave-assisted Synthesis of Nanomaterials in Aqueous Media Babita Baruwati, Vivek Polshettiwar and Rajender S. Varma, 176, 
Subject Index, 217, 

CHAPTER 1

Fundamentals of Aqueous Microwave Chemistry

VIVEK POLSHETTIWAR AND RAJENDER S. VARMA

Sustainable Technology Division, National Risk Management Research Laboratory, U.S. Environmental Protection Agency, 26 W. Martin Luther King Dr., MS 443, Cincinnati, Ohio 45268, USA

1.1 Introduction

The first chemical revolution changed modern life with excellent amenities and services, but also created the serious problem of environmental pollution. Now, 150 years later, we need to develop the concept of 'green chemistry' to help safeguard human life. The core principle of this concept is to protect the environment, not by cleaning it up, but by discovery of new chemistry and chemical processes that avert pollution. The concept of green chemistry prompts the chemical and pharmaceutical industries to consider the impact on human life when new chemicals are produced and introduced into our society. Thus, we can develop innovative pathways by rethinking chemical design from the ground up, to create products that stimulate our economy and lifestyles, without damaging our environment and surroundings. Green chemistry has emerged as a discipline that permeates all aspects of chemistry.

A myriad of drugs are required by society in short periods of time. To achieve this goal, medicinal chemists have been under increased demands to produce bio-active drug molecules, because of the high molecular complexity in drug discovery processes accompanied by time constraints. The central focus of pharmaceutical green chemistry is the development of efficient and environmentally benign synthetic protocols.

1.2 Green Chemistry Approach

Green chemistry is a vast and multifaceted field. The principles of green chemistry can be used to evaluate the greenness of a particular synthetic protocol. These principles deal with several issues, such as preventing the use of volatile and toxic solvents, the quantity and reusability of catalyst and reagents employed, the use of benign chemicals, atom-economic synthetic methods with a minimum number of chemical steps (which selectively generate the desired product without producing any by-products), energy efficient and mild reaction conditions, and chemical waste produced (Figure 1.1). It is not anticipated that any synthetic protocol will satisfy all green chemistry principles, but the more it satisfies the greener the process will be.

Solvents play a key role in deciding the environmental fate of a chemical process and have a huge impact on its cost, safety and health issues. The volatile and highly flammable solvents that are commonly used are the foremost source of ecological pollution and are rapidly rising on the green chemistry agenda. The use of reaction solvents, however, cannot be avoided as they are necessary for various steps such as the mixing of reactants, harmonized supply of heat and energy, and also in some cases to control the regio- and chemoselectivity of reactions.

There are assorted approaches for the development of environmentally friendly methods. The replacement of toxic reaction solvents with benign media is one of the best ways to make a protocol greener. While solvent replacement is a successful approach, it alone may not be enough. The entire development process must be well thought out, considering factors such as atom economy, energy efficiency and use of benign and naturally available renewable resources, and the solvent should be only one part of this. In addition, toxic solvents should not only be avoided during reaction but also after completion of the reaction; their use for isolation and purification of products (which involves the use of excess amounts per mass of final products) should be prevented or minimized.

Toxic solvents can be replaced by various non-conventional alternatives with superior ecological, health and safety properties, such as:

• bio-solvents: solvents produced from renewable resources, e.g. ethanol produced by fermentation of sugar-containing feeds and starchy feed materials;

• supercritical fluids, e.g. CO2;

• benign ionic liquids that have low vapor pressure and restrain release into the environment;

• fluorous and re-generable biphasic media.

1.3 Water as Green Solvent

To reduce the environmental impact resulting from the use of toxic solvents in chemical production, the identification and use of "green" solvents is a top priority. A solvent-free process is another answer, as one of the green chemistry principles states that the use of no toxic solvent makes the protocol green; however, this is not true in every case, and in fact this is how we misinterpret these principles. This particular green chemistry principle is only valuable if the developed solvent-free protocol works at the industry level (or at least the pilot plant level). Simply carrying out the reactions at small scale in the laboratory has no value as, at the bench-scale, small amounts of reactants can be mixed without solvent, but this is not feasible at the kilogram level, where a lack of reaction medium may lead to overheating of the reaction mixture because of the inadequate heat- and mass-transfer.

Biphasic technologies, using fluorous and ionic liquids along with aqueous systems and supercritical carbon dioxide, have formed the main thrust of this green solvent movement. However, the cost and toxicity of ionic liquids are prohibitive. Water appears to be a better option because of its abundant, nontoxic, non-corrosive, and non-flammable nature. In addition, water can be contained because of its relatively higher vapor pressure as compared to organic solvents, making it a green and sustainable alternative.

The major difficulty with using water as a solvent is the insolubility of most of organic reactants, making reaction mixtures heterogeneous. One way to overcome this is by using phase-transfer catalysts, but their expensive nature means that the resulting method is not economical. Product isolation from aqueous reaction mixture is another critical issue. Usually, evaporation of water is an option, but this is not an energy-efficient technique. Interestingly, these challenges can be tackled successfully by using the microwave (MW) heating technique for reactions in aqueous medium.

1.4 Why Microwaves?

Conventional processes of chemical synthesis are orders of magnitude too slow...

Details zur Ausgabe

• Verlag: Royal Society of Chemistry
• Erscheinungsdatum: 2010
• Sprache: Englisch
• ISBN 10: 1849730385
• ISBN 13: 9781849730389
• Einband: Gebundene Ausgabe
• Anzahl der Seiten: 228
• Herausgeber: Polshettiwar Vivek, Varma Rajender S.
• Kontakt zum Hersteller: Nicht verfügbar
• Verantwortliche Person: Nicht verfügbar