Solventless Reactions SLR

Green Separation Processes. Edited by C. A. M. Afonso and J. G. Crespo Copyright 2005 WILEY-VCH Verlag GmbH Co. KGaA, Weinheim ISBN 3-527-30985-3 

Ionic liquids are a new and remarkable class of designer solvents [9] with negligible vapor pressure for chemical syntheses because their properties such as solubility, density, refractive index, and viscosity can be tuned to suit specific requirements [10, 11], Water is a relatively more environmentally friendly alternative for organic synthesis, but its appHcation has been limited so far [6]. Supercritical carbon dioxide is yet another clean solvent but it generally requires a high-pressure reactor [12], 

PTC reactions, especially under microwave irradiation, have been discussed at length recently [14b] and are not included in this chapter. Reactions between neat reactants, with and without soHd inorganic supports and with microwave assistance are described herein with the salient advantages of the processes as they relate to environment, energy consumption, and recycHng of materials. 

Solvendess organic reactions, neat reagents (solid-solid or solid-liquid) react together in the absence of a solvent and have been well reviewed as a fast developing technology [14a, 15] the postulated model by Scott et al. for such solventless reactions was proposed for better understanding the mechanism [16], Some selected representative reactions under solvent-free conditions are discussed below with emphasis on product separation. 

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