Tuning the Catalytic Performance of Novel Composites Based on ZIF-8 and Nafen through Dimensional and Concentration Effects in the Synthesis of Propylene Glycol Methyl Ether

Zeolitic imidazolate framework (ZIF-8, Zn(2-meIm)₂) and composites based on ZIF-8 and alumina nanofibers (Nafen^TM), i.e. ZIF-8/Nafen, were demonstrated to be efficient heterogeneous catalysts for the reaction of methanol with propylene oxide to produce propylene glycol methyl ether (PGME), which is a member of the family of glycol ether solvents used for a wide variety of consumer products and industrial applications. Both the reaction rate and the selectivity toward PGME were found to decrease with increasing crystal size of the ZIF-8 material, which was related to the change in the number of basic sites and their accessibility. The investigation of ZIF-8/Nafen composites revealed the dependence of their catalytic performance on the amount of the ZIF-8 component. In particular, the activity was affected by the crystal size of the ZIF-8 material and the nature of acid-base sites in its framework.