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chemical processes, lately zeolites are also employed in various other applications, e.g., electronic, optical, and medical.
• Inorganic nature with robust frameworks.
• High stability at elevated temperatures and harsh chemical environments.
• Strong acid/base properties.
• Exceptional selectivity.
Although the zeolites have been considered the backbone of refineries, still they
encounter various limitations and disadvantages like smaller pore size, pore volume, and specific surface area. Hence, discovery of new materials to overcome the
limitations of zeolites in refineries is very much necessary.
3 MOFs: Metal Organic Frameworks
MOFs are considered as metal-organic hybrid materials imitating classical inorganic zeolites. Since both of them offer flexible synthesis processes and structural
diversity, the researchers are engrossed in the development of new zeolites and
MOFs. Recently the modifications and development of MOFs are comparatively
targeted more due to the ease of tailoring properties for using them in the targeted
applications. They differ from zeolites only by their large surface area, higher pore
sizes, and higher pore-specific volumes. MOFs are synthetic materials; according to
Cambridge Crystal Database, more than 50,000 structures have been reported. The
pliability in preparation methods of MOFs offers greater scope of their
diversification.
3.1 Structure and Nomenclature
A coordination polymer is an inorganic or organometallic polymer structure
containing metal cation centers linked by ligands extending in 1, 2, or 3 dimensions.
A subclass of these are the metal-organic frameworks, or MOFs, that are coordination networks with organic ligands containing potential voids [17, 21]. MOFs are
hybrid crystalline porous materials in which inorganic building units are connected
to organic linkers by coordination bonds of moderate strength. MOFs consist of
positively charged metal ions being coordination centers, linked by a diversity of
polyatomic organic linking ligands. This kind of structure of MOFs has resulted in
3D cage-like porous materials with high thermal and mechanical stability. Their
nomenclature follows the similar format as that of zeolites, i.e., three letters followed by a number, e.g., MIL-47 and MOF-48. The three letters used for representing the new solid can selected accordingly:
• Briefing the geographic origin of new solid
• Kind of solid material component, e.g., MOF-n, COF-n30 (covalent organic
framework), RPF-n (rare-earth polymeric framework)
Subhashini and T. Mondal
chemical processes, lately zeolites are also employed in various other applications, e.g., electronic, optical, and medical.
• Inorganic nature with robust frameworks.
• High stability at elevated temperatures and harsh chemical environments.
• Strong acid/base properties.
• Exceptional selectivity.
Although the zeolites have been considered the backbone of refineries, still they
encounter various limitations and disadvantages like smaller pore size, pore volume, and specific surface area. Hence, discovery of new materials to overcome the
limitations of zeolites in refineries is very much necessary.
3 MOFs: Metal Organic Frameworks
MOFs are considered as metal-organic hybrid materials imitating classical inorganic zeolites. Since both of them offer flexible synthesis processes and structural
diversity, the researchers are engrossed in the development of new zeolites and
MOFs. Recently the modifications and development of MOFs are comparatively
targeted more due to the ease of tailoring properties for using them in the targeted
applications. They differ from zeolites only by their large surface area, higher pore
sizes, and higher pore-specific volumes. MOFs are synthetic materials; according to
Cambridge Crystal Database, more than 50,000 structures have been reported. The
pliability in preparation methods of MOFs offers greater scope of their
diversification.
3.1 Structure and Nomenclature
A coordination polymer is an inorganic or organometallic polymer structure
containing metal cation centers linked by ligands extending in 1, 2, or 3 dimensions.
A subclass of these are the metal-organic frameworks, or MOFs, that are coordination networks with organic ligands containing potential voids [17, 21]. MOFs are
hybrid crystalline porous materials in which inorganic building units are connected
to organic linkers by coordination bonds of moderate strength. MOFs consist of
positively charged metal ions being coordination centers, linked by a diversity of
polyatomic organic linking ligands. This kind of structure of MOFs has resulted in
3D cage-like porous materials with high thermal and mechanical stability. Their
nomenclature follows the similar format as that of zeolites, i.e., three letters followed by a number, e.g., MIL-47 and MOF-48. The three letters used for representing the new solid can selected accordingly:
• Briefing the geographic origin of new solid
• Kind of solid material component, e.g., MOF-n, COF-n30 (covalent organic
framework), RPF-n (rare-earth polymeric framework)
Subhashini and T. Mondal