Activity of amino-functionalised mesoporous solid bases in microwave-assisted condensation reactions☆

Abstract Aminopropylated functionalised hexagonal mesoporous silicas (HMS) and SBA-15 materials with different amino-loadings (5–30 wt.% NH 2 ) were synthesized, characterised and their catalytic activities were subsequently investigated in the microwave-assisted Knoevenagel condensation of cyclohexanone and ethyl cyanoacetate as well as in the Michael reaction between 2-cyclohexen-1-one and nitromethane. The effects of the quantity of the catalyst in the reaction as well as a variety of microwave parameters including the power, temperature and time of microwave irradiation were optimised. High activities and selectivities to the condensation product could be achieved at short times of microwave irradiation for both base-catalysed processes. The low loaded HMS-5%NH 2 and higher loaded SBA-15-20%NH 2 were found to give the best activities in the reactions. This observation seems to be related to the significant deterioration observed in textural properties of HMS materials at amino-loadings larger than 10%.