A Spatially Orthogonal Hierarchically Porous Acid-Base Catalyst for Cascade and Antagonistic Reactions
organic molecules are of great importance to academic and industrial chemistry
and typically synthesised from smaller building blocks by multistep reactions.
The ability to perform multiple (distinct) transformations in a single reactor would greatly reduce the number
of manipulations required for chemical manufacturing, and hence the development
of multifunctional catalysts for such one-pot
reactions is highly desirable. Here we report the synthesis of a hierarchically
porous framework, in which the macropores are selectively functionalised with a
sulfated zirconia solid acid coating, while the mesopores are selectively
functionalised with MgO solid base nanoparticles. Active site compartmentalisation and substrate channelling protects base catalysed triacylglyceride transesterification from poisoning by free fatty acid impurities (even at 50
mol%), and promotes the efficient two-step cascade deacetylation-Knoevenagel condensation of dimethyl acetals to cyanoates.