Introduction to Microwave Chemistry

Keywords Introduction Theory Equipments Safety precautions Heterocyclic synthesis 

Rauf and N. N. Farshori, Microwave-Induced Synthesis of Aromatic Heterocycles, SpringerBriefs in Green Chemistry for Sustainability, DOI 10.1007/978-94-007-1485-4 l, The Author(s) 2012 

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Teaching Lab Kit (Fig. 3.5) This is a basic rotor for standard organic reactions allowing an introduction to microwave-mediated chemistry in teaching laboratories. It is designed for 16 x 20 mL glass vessels with operation limits of 1.5 bar and ca. 150 °C. 

Recently it has been shown that the microwave-assisted decoration of the 2(lff)-pyrazinone scaffold can allow an easy introduction of different substituents at the C-3 and even to the less reactive C-5 position [29]. Taking full advantage of combinatorial principles, some of these pathways were transferred to microwave-enhanced solid-phase chemistry, opening the way for the generation of many biologically interesting structures [108]. 

This book is written primarily to help students at undergraduate and graduate levels to understand and apply microwave techniques to organic synthesis, using commercially available microwave reactors. It is hoped that the application of different kind of microwave reactors will help to spread ideas of microwave technologies. It should also serve as an introduction to the field for the industrial chemists with no prior training in microwave assisted organic chemistry. 

The book will provide an introduction to the theory of microwave chemistry as well as practical laboratory manual by describing the methods of making a large number of compounds. Listing of the chemicals and equipment used in the syntheses and descriptions of the procedures and even the postsynthetic analyses will be very useful for the readers help them to design their own microwave reactions. 

The high-temperature solution procedure was recently modified by the introduction of microwave-assisted (MW) polycondensation. This technique now widely used in organic chemistry, employed to promote chemical reactions in extremely fast and sometimes unconventional ways. The MW-assisted synthesis of PAs was performed to promote the condensation of aromatic diacids and diamines under Yamazaki conditions. The conventional heating system, i.e., temperature control oil bath, is replaced by the MW system, which... 

Chapter 1 provides an introduction to modem synthetic chemistry with emphasis on topics such as solvent selection, catalyst choice, and a discussion of common challenges associated with functional group synthesis. This chapter also includes a detailed discussion of how to adapt conventionally heated reactions to microwave-assisted versions. 

The microwave chemistry can be applied to practically all inorganic families that do exist (see Introduction). Based on the literature, some interesting facts have been reported and can be summarized as follows stabilization of metastable and novel phases, increase of the phase purity and phase selectivity, short crystallization times and narrow particle-size distribution. 

This chapter aims to discuss and summarize theoretical and practical aspects of such plasma interfaces, presenting the existing examples from our own recent work on plasma electrochemical reactions between typical ionic liquids and plasmas. First, we address the plasma state and essential properties with respect to its application in electrochemistry. Today, low temperature plasmas - mostly in the form of radiofrequency or microwave plasmas - play an important role in the treatment or modification of solid surfaces. However, as plasma chemistry is usually not an element of chemistry curricula, we include a very brief introduction but refer the reader to the literature for more detailed information. 

There are distinct advantages of these solvent-free procedures in instances in which catalytic amounts of reagents or supported agents are used, because they enable reduction or elimination of solvents, thus preventing pollution at source . Although not delineated completely, reaction rate enhancements achieved by use of these methods may be ascribed to nonthermal effects. Rationalization of micro-wave effects and mechanistic considerations are discussed in detail elsewhere in this book [25, 244], There has been an increase in the number of publications [23c, 244, 245] and patents [246-256], and increasing interest in the pharmaceutical industry [257-259], with special emphasis on combinatorial chemistry and even polymerization reactions [260-263], and environmental chemistry [264]. The development of newer microwave systems for solid-state reaction [265], and introduction of the concepts of process intensification [266], may help realization of the full potential of microwave-enhanced chemical syntheses under solvent-free conditions. 

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