Ring‐Opening Polymerization of l‐Lactide to Cyclic Poly(Lactide) by Zeolitic Imidazole Framework ZIF‐8 Catalyst

Abstract

The catalytic activity of ZIF-8 in the ring-opening polymerization of l-lactide without solvents or cocatalysts is presented for the first time. Two different synthetic strategies have been applied for synthesizing ZIF-8, either under solvothermal condition or by spray-drying procedure. Their catalytic activities are found to be correlating with the presence of open active sites in ZIF-8 structure. The structural defects that afford active acid and basic sites are supposed to cooperatively catalyze the reaction. ZIF-8 assembled by spray-drying technique, displays a superior catalytic activity at temperature of 160 °C, leading to the formation of high molecular weight cyclic polylactide. The ZIF-8 catalysts could be recycled and reused without any significant loss of catalytic activity.

Encapsulation of Phosphorescent Pt(II) Complexes in Zn-Based Metal–Organic Frameworks toward Oxygen-Sensing Porous Materials

“…When the complex@ZIF-8 product is dried after synthesis, the solvate shell is evaporated, resulting in a super pore “rattle” with the complex inside. It has been shown for ZIF-8 that synthesis procedures which lead to the targeted addition of defects in the ZIF-8 structure increase the surface area by 100 to 250 m 2 g –1 (and also the pore volume). , Also, additional reactants can change the ZIF-8 surface area . Here, the in situ synthesis of the complex@ZIF-8 composites requires slightly inherent differences in the synthesis conditions from the neat ZIF-8 .…”

Metal–organic frameworks as catalysts for fructose conversion into 5‐hydroxymethylfurfural: Catalyst screening and parametric study

“…A series of Zr/Zn and Cr cluster‐based MOFs were prepared, characterized, and studied as catalysts for the conversion of fructose to 5‐HMF. MIL‐101(Cr), [ 45 ] MIL‐101(Cr)‐SO 3 H, [ 46 ] MIL‐101(Cr)‐NH 2 , [ 47 ] MOF‐808, [ 39 ] UiO‐66(Zr), [ 48 ] MOF‐5, [ 49 ] ZIF‐8 (SV), [ 50 ] ZIF‐8 (SP), [ 51 ] ZIF‐8 (MW), [ 52 ] ZIF‐8 (RT), [ 53 ] TZT, [ 54 ] and μEMTZT [ 55 ] were prepared for comparison using methods reported elsewhere (see sections S2 in the Supporting Information for details on the synthesis).…”

Selectivity Control in the Oxidative Ring-Opening of Dimethylfuran Mediated by Zeolitic-Imidazolate Framework-8 Nanoparticles

“…Several reactions have been carried out using ZIF-8, one of the most studied prototypical ZIF compounds, as a solid catalyst such as Knoevenagel condensation, 29 transesterification, 30 CO 2 fixation reaction, 31 and ring-opening polymerization. 32 Notably, some of these examples point out that the bifunctional acid/basic character of the ZIF-8 is the key for the efficient catalysis of some reactions. Acidity is associated with the Lewis-acid Zn +2 ions, while the nitrogen moieties from the imidazole linkers provide the basic sites.…”

“…However, to date, studies on ZIFs have mainly focused on synthesizing new ZIFs and investigating their potential in gas separation/storage , and in biomedical applications, while their catalytic properties have not been fully explored, thus being underexploited yet. Several reactions have been carried out using ZIF-8, one of the most studied prototypical ZIF compounds, as a solid catalyst such as Knoevenagel condensation, transesterification, CO 2 fixation reaction, and ring-opening polymerization . Notably, some of these examples point out that the bifunctional acid/basic character of the ZIF-8 is the key for the efficient catalysis of some reactions.…”