Separation of Propylene and Propane Using Metal–Organic Frameworks.

Propylene (C3H6) is a crucial olefin raw material used in the production of polypropylene, which is the world's second-most produced synthetic plastic. Separating propylene from propane (C3H8) is an important and significant challenge for industry due to the similar molecular sizes and physical properties of these gases. At present, the usual method for this separation is energy-intensive cryogenic distillation, which has low efficiency and high energy consumption. Therefore, an energy-efficient alternative way is in an urgent demand. Metal-organic frameworks (MOFs) are promising candidates for propylene/propane separation, thanks to the well-defined, designable, modifiable, and flexible structures. This review provides a summary of a recent development of MOFs that are able to discriminate between propylene and propane. The key factors that determine the separation performance of MOFs, primarily from the perspectives of pore size, presence of open metal sites (OMS) and MOFs membranes are summarized. Besides, the challenges that must be addressed for the further development of separations utilizing MOFs are also discussed. [ABSTRACT FROM AUTHOR]