Microwave-Assisted Chemistry: a Rapid and Sustainable Route to Synthesis of Organics and Nanomaterials

Vivek Polshettiwar; Mallikarjuna N. Nadagouda; Rajender S. Varma

doi:10.1071/CH08404

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Microwave-Assisted Chemistry: a Rapid and Sustainable Route to Synthesis of Organics and Nanomaterials

Vivek Polshettiwar ^A , Mallikarjuna N. Nadagouda ^A and Rajender S. Varma ^A ^B

+ Author Affiliations

- Author Affiliations

^A Sustainable Technology Division, National Risk Management Research Laboratory, US Environmental Protection Agency, 26 W Martin Luther King Drive, MS 443, Cincinnati, OH 45268, USA.

^B Corresponding author. Email: varma.rajender@epa.gov

Dr Vivek Polshettiwar was born in India and received an M.Sc. degree in Chemistry from Amravati University, India. He then moved to Defense Research & Development Establishment (DRDE), Gwalior, India, where he received his Ph.D. (2005) under the supervision of Prof. M. P. Kaushik. He investigated nano-structured functionalized silica for catalysis, with Prof. J. J. E. Moreau in 2006 for his postdoctoral research at ENSCM, Montpellier, France. Currently, he is working as an ORISE postdoctoral fellow, researching greener synthetic methods and nano-catalysis for bio-active compounds, with Prof. Rajender S. Varma at the US EPA.

Dr Mallikarjuna N. Nadagouda, born in India, received his Ph.D. (2003) from Gulbarga University. He worked with Prof. Alan G. MacDiarmid (2000 Nobel Laureate) in the University of Texas at Dallas and has been a recipient of an Oak Ridge Institute Science and Education postdoctoral fellowship to work with Prof. Rajender S. Varma at NRMRL, US EPA, before joining his current position as a material scientist at Pegasus Technical Services, Cincinnati, OH. He has worked in the areas of analytical chemistry, green chemistry, polymer blends, solid coatings, nanomaterials, polymer nanocomposites, and solid state chemistry.

Prof. Rajender S. Varma was born in India (Ph.D., Delhi University 1976). After postdoctoral research at the Robert Robinson Laboratories, Liverpool, UK, he was a faculty member at Baylor College of Medicine and Sam Houston State University before joining the US Environmental Protection Agency in 1999. He has over 35 years of research experience in management of multi-disciplinary technical programs that includes nanomaterials and the development of environmentally friendlier alternatives for synthetic methods using microwaves, and ultrasound, etc. He has published over 280 scientific papers and has been awarded six US patents.

Australian Journal of Chemistry 62(1) 16-26 https://doi.org/10.1071/CH08404
Submitted: 24 September 2008 Accepted: 25 November 2008 Published: 21 January 2009

Abstract

The use of emerging microwave (MW)-assisted chemistry techniques in conjunction with benign reaction media is dramatically reducing chemical waste and reaction times in several organic syntheses and chemical transformations. The present review summarizes recent developments in MW-assisted synthesis, name reactions and organic transformations, and rapid generation of nanoparticles with uniform size distribution. Greener protocols have been developed for the synthesis of various bio-active heterocycles, namely 1,3,4-oxadiazoles, 1,3,4-thiadiazoles, 1,3-dioxanes, pyrazoles, hydrazones and 3,4-dihydropyrimidin-2(1H)-ones, which proceed under the influence of microwaves and using eco-friendly conditions. These high-yielding methods were catalyzed efficiently by solid-supported Nafion NR50 under solvent-free conditions and polystyrene sulfonic acid in aqueous media. The eco-friendly nucleophilic substitution chemistry in water to generate cyclic amines via double N-alkylation of primary amines or hydrazines by dihalides or tosylates enables the greener synthesis of a range of pharmaceutically active heterocycles. Similarly, efficient MW synthesis of various azides, thiocyanates, and sulfones in aqueous medium occurs wherein nucleophilic substitution reaction takes place in the absence of a phase-transfer catalyst. Bulk and shape-controlled synthesis of noble nanostructures via MW-assisted spontaneous reduction of noble metal salts using α-d-glucose, sucrose, and maltose is described. MW method also accomplishes the cross-linking reaction of poly(vinyl alcohol) with metallic systems such as Pt, Cu, and In; bimetallic systems, namely Pt–In, Ag–Pt, Pt–Fe, Cu–Pd, Pt–Pd, and Pd–Fe; and single-walled nanotubes, multi-walled nanotubes, and buckminsterfullerenes (C-60). The strategy is extended to the formation of biodegradable carboxymethyl cellulose (CMC) composite films with noble nanometals; such metal decoration and alignment of carbon nanotubes in CMC is possible using a MW approach that also enables the shape-controlled bulk synthesis of Ag and Fe nanorods in poly(ethylene glycol).

Acknowledgement

V.P. and M.N.N. were supported by the Postgraduate Research Program at the National Risk Management Research Laboratory administered by the Oak Ridge Institute for Science and Education through an interagency agreement between the US Department of Energy and the USA EPA.

References

Microwave-Assisted Chemistry: a Rapid and Sustainable Route to Synthesis of Organics and Nanomaterials

Abstract

Acknowledgement

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