Linear α-olefin oligomerization and polymerization catalyzed by metal-organic frameworks

In the industry of petrochemicals, oligomerization of α-olefins, mainly ethylene and propylene, is an important process that produces linear α-olefins (LAOs). Industrial processes for selective LAOs rely on various homogenous catalysts in the presence of alkyl aluminum activators. Recently, heterogeneous catalysts have largely been applied for α-olefin oligomerization and polymerization due to their high selectivity, stability, and reusability. In this context, metal-organic frameworks (MOFs), adopting high surface area, tunable pore structures, and enhanced physicochemical properties achieved through postsynthetic modification, have emerged as promising catalytic systems for this purpose. In this review, we provide a comprehensive overview (124 references) of using designed MOFs, MOFs with postsynthetic modification through linker metalation and mixed-metal clusters for selective oligomerization of α-olefins. We subsequently highlight the use of MOFs as non-selective catalysts for α-olefin oligomerization. Additionally, MOFs that catalyze α-olefin polymerization are also presented. Selective ethylene oligomerization conceptually proceeds through metallacycle mechanism, on the other hand, linear chain growth is the accepted mechanism for ethylene oligomerization and polymerization; accordingly, such mechanistic hypotheses using MOFs are described in detail. We, finally, point out challenges and perspectives for the future research of using MOFs as catalysts for α-olefin oligomerization and polymerization.