Silica gel as an accessible substrate with high surface area can be modified by propyl S-sulfonic acid. Silica-bonded S-sulfonic acid (SBSSA), silica-bonded N-propyl sulfamic acid (SBNPSA) and silica-bonded N-propylpiperazine sulfamic acid (SBPPSA) as highly efficient heterogeneous solid acid catalysts for the green synthesis of various organic compounds including highly important biological active heterocycles have been developed by many scientists recently. The superior advantage of these heterogeneous catalysts is that they can be recovered and reused several times without the loss of their efficiency. This book will help the reader to understand the preparation and utilization of SBSSA, SBNPSA and SBPPSA as solid heterogeneous catalysts for organic transformations in both theoretical and practical aspects.

Rajesh H. Vekariya obtained his Master Degree in organic chemistry in 2012 from the Gujarat University, Ahmedabad, India. Currently, he is pursuing his Ph.D. under the guidance of Dr Hitesh D. Patel. His research focuses on the synthesis of organic intermediates via green chemistry and their utilization in the synthesis of bio-active compounds.