Clays: Types and Applications

Abstract

Clay is a widely distributed, abundant mineral resource of major industrial importance for an enormous variety of uses. In common with many geological terms, the term “clay” is ambiguous. Cationic and anionic clays have attracted the greatest attention in the area of catalysis from the last decades. Clays are providing specific features like high versatility, wide range of preparation variables, use in catalytic amounts, ease of set-up and work-up, mild experimental conditions, easy work-up procedure, gain in yield and/or selectivity, low cost, recyclablity etc. These properties make them more applicable towards establishing environmentally benign technologies. Additionally, the possibility of upgrading these materials via intercalation process opens new and interesting standpoints, also considering possible shape selective advantages. In this review, we are focusing types of clays (anionic/cationic), their modified forms as well as catalytic and other important applications of cationic and anionic clays for various organic transformations.