Heterogeneous transesterification catalyzed by silicas containing basic sites

Type MCM-41 hybrid silicas that contain cationic surfactants in their mesopores possess very strong basic sites, siloxy site (SiO-), which are able to promote transesterification reactions. However, the low catalytic stability of these materials hinders their reuse in successive cycles. This work investigates the stability of MCM-41 hybrid silicas synthesized using the polymerizable surfactant 1-cetyl-3-vinylimidazolium bromide (CVIMBr). The surfactant was synthesized by the quaternization reaction between 1-vinylimidazole and 1-bromohexadecane. The CVIM-MCM-41 hybrid silicas were synthesized, polymerized using ultraviolet irradiation, and evaluated in catalysis of the model transesterification reaction of ethyl acetate with methanol. The characterization results confirmed formation of the CVIMBr surfactant. The CVIM-MCM-41 hybrid silicas showed lower catalytic activity than the CTA-MCM-41 hybrid silica, but had greater catalytic stability in up to 5 successive uses.

Automated summary

In this study, MCM-41 hybrid silicas were synthesized using a novel polymerizable surfactant CVIMBr, which showed lower catalytic activity but higher stability in up to 5 successive uses in the transesterification reaction of ethyl acetate with methanol.