High-Flux and High-Purity Separation of Methyl tert-Butyl Ether and Methanol with a Superwetting Membrane.

Methyl tert-butyl ether (MTBE), widely used to enhance gasoline octane ratings and combustion efficiency, is primarily produced by the catalytic reaction of methanol (MeOH) with isobutylene, where excess MeOH improves conversion efficiency but leads to challenges: MeOH forms an azeotropic mixture with MTBE at 14.3 wt % concentration, complicating separation due to similar molecular sizes and azeotropic behavior, which renders membrane-based approaches ineffective. Herein, we report a superwetting membrane-based strategy that combines low-polar octadecyl trimethoxysilane-modified porous electrospun SiO2-TiO2 membrane (STM-C18) with high-polar H2O as the inductive agent for high-flux and high-purity separation of MTBE and MeOH. The relatively low-polar MTBE can rapidly permeate the porous STM-C18 and be selectively separated by interacting with the nonpolar -C18, while the relatively high-polar MeOH is being blocked due to the additive H2O dragging it by forming strong polar interactions. The SWM system demonstrated exceptional performance, with a high flux of 322 L m-2 h-1 and MTBE purity exceeding 99.4 wt %, highlighting its significant potential for practical application in MTBE production.