Catalytic applications of metal-organic frameworks

Project: Project at a former HEI

Description

Metal-organic frameworks (abbreviated to MOFs) are a relatively new class of material, and are comprised of a grid-like assembly of metal atoms and organic linkers. MOFs have shown great promise as solid state catalysts as they contain pores in which reactions can occur, and the size and shapes of these pores can be controlled by altering the organic linkers thus tailoring the reaction conditions in the pores. In this project we have developed new functionalised linkers, prepared and characterised new MOFs based on these, and studied computationally the adsorption properties of the new materials for chiral and other separations. In addition, we have shown that MOFs can act as catalysts, increasing the rates of cycloaddition reactions to produce cyclic organic compounds. This was a joint project with material chemists from the University of Bath and organic chemists from UEA.

In the part of the project carried out at the University of Edinburgh, a wide variety of MOFs were assessed for the separation of liquid phase mixtures such as the separation of xylene mixtures. We furthermore looked in detail at the separation of chiral diol mixtures identifying the factors that contributes to high ee-values. Additionally, we assessed the gas storage and separation properties of MOFs synthesized at Bath. One paper has been published to date, another three are in preparation.

As a whole, this project has brought together chemists and chemical engineers, and successfully integrated asymmetric organic synthesis, inorganic materials chemistry and computational modelling. Three PhD students will shortly graduate, each with a unique insight at the strategically important chemistry-chemical engineering interface, and direct experience of the three strands that make up this synergic project.

Key findings

1) We identified a simple criteria based on the pore size of a MOF that allows a identifying materials that are selective for either para-xylene or ortho-xylene very easily and forms the first important step towards large scale screening to identify promising MOFs for this application.
2) Our work showed that while the chirality of the MOF framework assists the separation mechanism, the more dominant factor is the perfect match between guest-framework size and shape.
3) In collaboration with the project partners in Bath and UEA, we synthesised MOFs that uses an upper rim-functionalised calix[4]arene dicarboxylic acid which itself can act as a host for guest molecules. Simulations suggest that such networks are likely to display interesting selectivity to guest molecules.
Short title£149,111.00
StatusFinished
Effective start/end date1/04/0830/09/11