facile knoevenagel condensation using sulfonic acid functionalized nanoporous silica (sba-pr-so3h)

knoevenagel condensation between barbituric acid and aldehyde was investigated in the presence of sulfonic acid functionalized nanoporous silica (sba-pr-so3h) and resulted in the formation of arylidene and bis-arylidene barbiturates. excellent yields and short reaction times are related to the high efficiency of sba-pr-so3h that the reactions take place easily in its nano-pores. sba-pr-so3h as an efficient heterogeneous nanoporous solid acid catalyst which was prepared by silica functionalization with (3-mercaptopropyl) trimethoxysilane followed by oxidation with h2o2, can be easily removed from the reaction mixture by simple filtration, and also recovered and reused without noticeable loss of reactivity.