Metal-organic frameworks (MOFs), are coordination polymers with a hybrid inorganic-organic framework comprising metal ions and organic ligands coordinated to said metal ions.

These materials are organized as mono-, bi- or tri-dimensional networks wherein the metal clusters are linked to each other by spacing ligands periodically. These materials have a crystalline structure and are generally porous.

In the present work, the research team has developed a method for hydrothermal preparation of porous aluminum carboxylates-based metal-organic frameworks in an aqueous medium. 

Among the various families of studied MOFs, those incorporating aluminum is more particularly sought by industries owing to the low production cost of this kind of materials. Moreover, as a light element, the aluminum based materials and in particular the aluminium carboxylates based materials may have high storage capacities for molecules such as H2, CH4, CO2…

The known processes for the preparation of MOFs, in particular of MOFs containing aluminum, usually take place in the presence of organic solvents often in relatively large quantities. However, when such processes must be carried out on a large scale, i.e. on an industrial scale, the use of large quantities of solvent may be problematic: high manufacturing cost, not environmentally or ecologically friendly.

In addition, aluminum based MOF solids obtained by the majority of known processes may not be adapted to the desired application as they may lead to a mixture of several materials, be in amorphous form or even contain undesirable secondary impurities not eliminated during the preparation of the MOF solid. Moreover, said solids do not always exhibit a sufficient adsorption capacity.
Thus, further steps, such as purification or crystallization steps, may be required so as to lead to a crystallized MOF solid, made up of a single phase, highly pure (free from any secondary product) and exhibiting a sufficient porosity.

To date, no methods exist for preparing aluminum based MOFs, in particular, aluminum carboxylate MOFs with the required purity, porosity and crystalline properties, which is cost effective, ecological and providing a good yield.
Thus, there is a need for:

• a method for preparing MOF type crystallized and porous aluminum carboxylates overcoming the defects, drawbacks and obstacles of the prior art.
• a method which is reproducible, ecological, industrially applicable and allowing the preparation of metal-organic framework, MOF, type crystallized and porous aluminum carboxylates.

Development stage

• Hydrothermal synthesis of 3 various solids made up of metal-organic framework have been demonstrated on a laboratory scale

Pending patents 

02077-01

Scope: hydrothermal process of aluminium and azocarboxylate-based metal-organic frameworks
Priority application: French patent application FR0806448 filed on November 18, 2008 and entitled « Procédé de préparation d’azocarboxylate aromatique d’aluminium poreux cristallisées de type metal organic framework »
Extensions in United States, Europe, Japan

02078-01

Scope: hydrothermal process of aluminium and carboxylate-based metal-organic frameworks
Priority application: French patent application FR0806449 filed on November 18, 2008 and entitled « Procédé de préparation hydrothermale de carboxylates d’aluminium poreux cristallisées de type metal organic framework »
Extensions in United States, Europe, Japan

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