Chemical and Environmental Engineering Group

New heterogenous catalysts for industrial chemical processes

Design of chiral catalysts
Nowadays there is a strong demand of chemical compounds possessing asymmetry elements, not only for drug or pharmaceutical syntheses but also because several other fields, for instance agrochemicals, perfumes and cosmetics or nutraceuticals synthesis, have increased their demand. Though there are different routes to prepare chiral compounds with high enantiomeric excess, asymmetric synthesis and chiral catalysis are one of the most interesting synthesis pathways from an environmental, economic and technologic point of view, since chiral catalysts allow preparing enantiomerically pure chiral compounds from prochiral substrates in high scale. However, most of the reported chiral catalysts are very complicate molecules which involves the use of several expensive reactants, so that their reutilization is compulsory to ensure the profitability of the chemical processes. In this research line, several studies are being accomplished in order to produce chiral heterogeneous catalysts, showing high catalytic activity and enantioselectivity and displaying enough selectivity for their utilization in continuous processes.

Hierarchical nanocrystalline zeolites and hybrid zeolitic-mesoporous materials
Zeolites are crystalline microporous metalosilicates characterized by their shape selectivity and their behaviour as molecular sieves, being employed in a variety of catalytic, adsorption and ion exchange processes. These materials have been usually synthesized as micrometer-sized crystals, and therefore with a reduced external surface area, which implies a strong limitation for the use of zeolites in reactions involving voluminous reactants. An increasing interest has emerged in the last years in order to reduce the steric constraints of traditional zeolites, and a variety of new strategies have been developed in order to introduce mesoporosity in zeolitic materials. As a consequence, a large family of zeolitic materials with hierarchical porosity has emerged, nanozeolites and hybrid zeolitic-mesoporous materials being two outstanding examples. The Chemical and Environmental Engineering Group is working in the synthesis of hierarchical nanocrystalline zeolites with MFI, BEA, MEL, MOR and FAU framework types. Al and/or Ti atoms are incorporated in the framework of these materials, which confers interesting properties in acid catalyzed and selective oxidation reactions, respectively. Moreover, new methodologies to obtain hybrid zeolitic-mesoporous materials are also being developed in order to employ these materials as catalysts in processes in which, due to their properties, the catalytic behaviour of hybrid zeolitic-mesoporous materials was better than conventional zeolites and mesoporous materials.

Design of acid heterogeneous catalysts
A plurality of processes in the chemical industry follows an acid catalysis mechanism (alkylation, etherification, esterification, acylation, isomerization, etc.). Most of the currently implanted processes use homogeneous acid catalysts (hydrofluoric acid, sulfuric acid, aluminum trichloride, etc.) and therefore show the potential risks and environmental drawbacks derived from the use of corrosive non-recoverable catalytic systems. The application of acid heterogeneous catalysts allows overcoming these problems, although they must first demonstrate to have catalytic activities at least similar to their homogeneous counterparts. The present research line of the Chemical and Environmental Engineering Group aims to the design and synthesis of solid catalysts with acid active sites. This includes systems based on organic acid functions (e.g. sulfonic acid groups) and inorganic acid functions (catalysts based on aluminum or acid metallic oxides), usually supported on porous materials (zeolites or mesostructured materials) in order to improve the textural properties of the catalyst. On the other hand, research efforts are also dedicated to the design of hybrid organic-inorganic materials based on the covering of pore walls of mesostructured materials with a nanometric layer of polymer having acid functionalities. The objective is to obtain a material which is similar to commercial acid resins (such as Amberlyst or Nafion) but with improved thermal stability and accessibility to the acid sites.

Design of heterogeneous catalysts with redox properties
Chemical processes involving oxidation or reduction reactions are very important in chemical industry and these forms the core of a large variety of important chemicals production processes. In these processes, catalysts play a crucial role so that their improvement, in any feature, leads to a direct upgrading of the considered process. Among the different transformations, selective oxidation of alkenes to lead epoxides is one of the most important routes for oxirane production. The industrial catalysts used in these processes, usually prepared by supporting metals with redox properties on silica, show several features which can be improved. Within this research line, several studies are being accomplished with the purpose to improve the catalytic activity of several oxidation catalysts. The actuations involves different strategies such as using different catalytic supports (amorfous materials, mesostructured solids, nano-crystalline zeolites), the use of different metal precursors to tune the redox properties or the macroscopic casting of catalysts in particulated solids for their use in fixed bed reactors.

Current research projects:

Preparación de nanopartículas silíceas mesoestructuradas modificadas para su aplicación en síntesis asimétrica y dosificación controlada de fármacos.

Financial Support: Ministerio de Ciencia e Innovación

  • Start Year: 2012
  • End Year: 2014

Sintesis de zeolitas de porosidad jerarquizada con zirconio para su aplicación en procesos catalíticos de interés energético y/o medioambiental

Financial Support: Universidad Rey Juan Carlos

  • Start Year: 2013
  • End Year: 2015