Editorial [Hot Topic: The Use of Heterogeneous Catalysts in Organic Synthesis (Guest Editor: Arpad Molnar)]

Part I of the second special issue of Current Organic Chemistry dedicated to the topic of the use of heterogeneous catalysts in organic synthesis, again, brings together experts of a few selected, important fields to highlight recent major achievements. I am pleased that by these contributions we can maintain the diversity established in the previous volume. The opening account by Srinivasan Palaniappan and Amalraj John (Indian Institute of Chemical Technology, Hyderabad, India) covers recent developments of polymer-based solid acid catalysts in organic synthesis. These inexpensive, stable materials or their salts, complexes and metal composites may be used as efficient and versatile catalysts. The main emphasis is on the characterization and use of polyaniline-based catalytic materials. The second review has been provided by Benjaram M. Reddy and Meghshyam K. Patil of the Indian Institute of Chemical Technology (Hyderabad, India) on the topic of the use of promoted zirconia solid acid catalysts for organic synthesis. At the time of its discovery, promoted zirconia was considered to be a new generation of acid catalysts catalyzing transformations of industrial importance and as such elicited extreme interest in this type of catalysts. Although these expectations have not been materialized, this review shows that promoted zirconia catalysts proved to be highly versatile in synthetic organic chemistry. The third chapter written by Basudeb Basu and his colleagues (Pralay Das and Sajal Das) from North Bengal University (Darjeeling, India) is devoted to developments of the last five years in KF/alumina promoted organic reactions. KF/alumina is a remarkably useful heterogeneous catalyst to promote many base-catalyzed organic transformations. Various applications, including its particularly attractive use in metal-catalyzed coupling reactions, have been treated accordingly. The final contribution to this issue (A. Molnar, University of Szeged) is a review about Nafion-silica nanocomposites. The use in organic synthesis of Nafion resins as useful catalysts was pioneered by Professor G.A. Olah in the 1970s and 1980s. An important discovery in 1996 by M.A. Harmer transforming Nafion beads into a new type of strongly acidic catalyst of high specific activity opened up new application possibilities. This timely account summarizes a decade-long vigorous and productive research activity. It is the sincere hope of both the contributing authors and myself that the readers will find the first part of this second special issue about heterogeneous catalysis in organic synthesis interesting and informative.