Reduction in the use of hazardous solvents and substances is one of the underlying concepts of green chemistry. Clean alternative solvent media exist, and include carbon dioxide, water, ionic liquids, and other benign media. In some cases, the transformation from an organic to a benign solvent is a relatively simple substitution. However, in many cases, the use of a benign solvent requires substantial process modification. This book highlights some of the reactions and processes that are currently being considered for conversion to benign solvents, and describes the modifications in these processes that will be needed to make the use of the benign solvent commercially viable. Scientific principles are developed for the analysis of these systems, and form the basis for understanding the role of the solvent in the chemical process.