Heterogeneous catalysis

Abstract

The use of the term “Heterogeneous Catalysis” within scientific journal titles in the chemical literature has been growing rapidly in the last 15–20 years, as the scientific data banks clearly reveal, while it is barely mentioned in the literature before the 1990s. The reason behind this can be found in the explosive growth of Green Chemistry. The “Twelve Principles of Green Chemistry” identify catalysis as one of the fundamental pillars of green chemistry (Principle no. 9), and heterogeneous catalysis, in particular, addresses the goals of green chemistry by providing easy separation of the product and catalyst, thereby eliminating the need for separation through distillation or extraction. In addition, environmentally benign catalysts, such as clays and zeolites, may replace more hazardous catalysts currently in use (Principles no. 1, 5, 8 and 10). Nevertheless, one must pay attention to the environmentally benign synthesis and degradation of heterogeneous catalysts at the end of their lifetime (Principle no. 10). A heterogeneous catalyst should be stable; no leaching of potentially toxic material should occur during the reactions and the best result would be no leaching of any material at all or negligible leaching of the active components. [excerpt]