UIO-67-TYPE METAL-ORGANIC FRAMEWORKS WITH ENHANCED WATER STABILITY AND METHANE ADSORPTION CAPACITY

The structure and properties of two new UiO-67-type metal–organic frameworks, along with their linker synthesis and powder and single crystal synthesis, are presented. The new MOFs, UiO-67-Me and UiO-67-BN, are based on 3,3-dimethylbiphenyl and 1,1-binaphthyl linker scaffolds, and show a much higher stability to water than the thoroughly investigated UiO-67, which is based on the biphenyl scaffold. On the basis of structure models obtained from single crystal X-ray diffraction, it is seen that these linkers are partly shielding the Zr cluster. The new materials have higher density than UiO-67, but show a higher volumetric adsorption capacity for methane. UiO-67-BN exhibits excellent reversible water sorption properties, and enhanced stability to aqueous solutions over a wide pH range; it is to the best of our knowledge the most stable Zr-MOF that is isostructural to UiO-67 in aqueous solutions. Access the research article here.

GREEN SYNTHESIS OF ZIRCONIUM-MOFs

The synthesis of Zr-MOFs under green, industrially feasible conditions was investigated. Two new compounds with bcu-topology and the fluorinated analogue of UiO-66 exhibiting fcu-topology were obtained and characterised. All products exhibit permanent porosity. In the bcu-frameworks the interaction with sulfate anions apparently induces an unusual eightfold connectivity of the Zr cluster. Access the research article here.

DETAILED STRUCTURE ANALYSIS OF ATOMIC POSITIONS AND DEFECTS IN ZIRCONIUM METAL-ORGANIC FRAMEWORKS

We report the structure of the Zr metal–organic frameworks (MOFs) UiO-66 and UiO-67 to very fine detail using synchrotron single-crystal X-ray diffraction and the synthesis method used to obtain single crystals. Zr terephthalate MOF UiO-66 is known to have missing linkers, and the nature of these are shown to be coordinating water and solvent molecules. Single crystals of the isoreticular material UiO-67 does not show such missing linker defects. Access the research article here.

TUNED TO PERFECTION: IRONING OUT THE DEFECTS IN METAL-ORGANIC FRAMEWORKS UiO-66

This systematic study has demonstrated the dramatic yet logical impact that the synthesis conditions can have on the properties of UiO-66. Seven potential pitfalls regarding sample ideality were investigated, affording the conclusion that the material systematically becomes more “ideal” when the BDC:Zr ratio and/or synthesis temperature are increased. Such gravitation toward ideality makes sense when one notes that linker deficiencies are the underlying cause of the majority of pitfalls. We suggest that increasing the synthesis temperature and/or BDC:Zr ratio shifts the solution equilibrium in favor of BDC-Zr bonds, aiding the “ironing out” of linker deficiencies. This approach ultimately yields “ideal” UiO-66 with unsurpassed thermal stability when the synthesis is performed with a 2:1 BDC:Zr ratio at 220 °C. Access the research article here.

A NEW ZIRCONIUM INORGANIC BUILDING BRICK FORMING METAL-ORGANIC FRAMEWORKS WITH EXCEPTIONAL STABILITY

Porous crystals are strategic materials with industrial applications within petrochemistry, catalysis, gas storage, and selective separation. Their unique properties are based on the molecular-scale porous character. However, a principal limitation of zeolites and similar oxide-based materials is the relatively small size of the pores, typically in the range of medium-sized molecules, limiting their use in pharmaceutical and fine chemical applications. Metal organic frameworks (MOFs) provided a breakthrough in this respect. New MOFs appear at a high and an increasing pace, but the appearances of new, stable inorganic building bricks are rare. Here we present a new zirconium-based inorganic building brick that allows the synthesis of very high surface area MOFs with unprecedented stability. The high stability is based on the combination of strong Zr−O bonds and the ability of the inner Zr6-cluster to rearrange reversibly upon removal or addition of μ3-OH groups, without any changes in the connecting carboxylates. The weak thermal, chemical, and mechanical stability of most MOFs is probably the most important property that limits their use in large scale industrial applications. The Zr−MOFs presented in this work have the toughness needed for industrial applications; decomposition temperature above 500 °C and resistance to most chemicals, and they remain crystalline even after exposure to 10 tons/cm2 of external pressure. Access the Research article here.

MOFs go green

The integration of MOFs into industrial relevant processes marks the shift towards green chemistry

Over the past 15 years, Metal-Organic Frameworks (MOFs) has been the subject of intense efforts in research and development, both in the laboratory and on the industrial scale. Why? Because, scientists believe the material can be developed for use in a variety of industrial processes. The challenge, however, has been a lack of clean and sustainable methods to develop the MOF-material. This is now history. A safe, environmental-friendly synthesis method has now been reported to be successful.

“The new method uses water instead of solvent to synthesize MOFs, which is a greener and much more sustainable way of producing the MOF-material,” said Sachin Maruti Chavan, Chief Technology Officer and co-founder.  

Greener and safer methods

The greener route of synthesis is developed by scientists at the University of Oslo and uses water instead of N,N Dimethylformamide (DMF), also known as solvent, to synthesize Zr-based MOFs. This green synthesis of MOFs is developed with respect to the environment, reactant choice and the synthesis design. Water is used as the reaction medium and therefore the synthesis is mindful of sustainability and environmental impact.

“This new method of synthesizing MOFs symbolizes how green chemistry and sustainability can be compatible with the requirements of industrial production,” Chavan highlights.

A Breakthrough

What does this mean? Well, with scientists being able to produce and manufacture the MOF-material in an environmental-friendly way, it means that companies like ProfMOF are able to fast-track the process of commercializing its products.

“We are now able to synthesize MOFs using water, which means the development of this synthesis is a measure breakthrough in the commercialization of MOFs,” said Svein-Olav Torø, Managing Director.

The future is now 

With a green and environmental-friendly synthesis method, one would think that commercialization is just around the corner. However, the new method of synthesizing MOFs is still under development and scientists needs to test the MOF-material for further development. The good news though, is that scientists are now one step closer and one chance greater at achieving the goal of making the product investor-ready and, hence, commercialize the unique and world-changing product for future utilization.

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