Straightforward synthesis of MTW-type magnesium silicalite for CO₂ fixation with epoxides under mild conditions

Aluminum-free magnesium silicalite with MTW topology (Mg-Si-ZSM-12) was fabricated via a straightforward hydrothermal synthesis route involving an initial acid co-hydrolysis step. Mg incorporation endowed superior basic properties to the MTW framework, as illustrated by CO₂ sorption and temperature programmed desorption plus the activity in a typical basic reaction, Knoevenagel condensation. Mg-Si-ZSM-12 catalyzed the coupling of atmospheric CO₂ with epoxides and led to the efficient production of cyclic carbonates with high yield and selectivity at relatively low temperature (down to 60 °C). The present strategy afforded a zeolitic solid base with regular 12-membered ring microporous channels that has potential application in CO₂ fixation.