The ability of zirconia and modified zirconia coated on cordierite honeycomb monolith as heterogeneous solid acid-base catalysts in selected liquid/vapour phase organic reactions is explained in this book. With a high active surface area, the catalyst coated on cordierite honeycomb monolith has advantages over powder form catalyst. A very thin layer of catalysts loaded on a monolith is very effective and provides a high active surface area, safe storage and a longer life time, and environmentally friendly safe disposal, as well as easy separation and total recovery from the reaction mixture...