9. Recent achievements and challenges for a greener chemical industry

The chemical industry is experiencing important changes, the driving force for which is not only the need to improve competitiveness and consolidate market positions while complying regulations and rules for the protection of the human health and of the environment, but also the increased awareness that in the near future all the raw-materials and energy chain supply will have to be reconsidered. In this context, in latest decades a pioneering role has been played by oxidation catalysis, which has been undergoing substantial modifications, both in process technology and in catalyst design, aimed to improve the performance of chemical processes especially in terms of selectivity, ameliorate the energy efficiency and decrease the costs associated to waste stream decontamination and pollutants abatement. Emblematic examples of achievements in this field are the following: 1. The shift from air-based, once-through processes to oxygen-based recycle processes, and the corresponding change from reactant-lean to oxidant-lean processes. 2. The synthesis of intermediates and monomers from alkanes by means of oxidative processes, in part replacing alkenes and aromatics as the traditional building blocks for the chemical industry. 3. The development of new types of heterogeneous catalytic systems for liquid phase oxidations that made possible the use of environmentally friendly oxidants, i.e., hydrogen peroxide and air, in place of oxidants like hydroperoxides (that lead to the co-formation of the product of reduction), HNO3 and Cr6+. However, new challenges are now driving researchers towards the exploration of new synthetic catalytic routes that use renewable raw materials in place of building blocks derived from oil, natural gas and carbon, adopt the intensification concept, decreasing risks associated to oxidation processes and lowering investment costs for new technologies, and make use of new types of catalysts not only for new synthetic pathways, but also for established industrial processes, so permitting the overcoming of apparently unsurpassable yields. In this report, a few examples of recent achievements in catalytic selective oxidation are described, that may well illustrate current trends, perspectives of development and future directions in this field.