Title Brønsted acidic hydrogensulfate ionic liquid immobilized SBA-15:[MPIm][HSO4]@SBA-15 as an environmentally friendly, metal- and halogen-free recyclable catalyst for Knoevenagel–Michael-cyclization processes Type JournalPaper Keywords Not Registered! Abstract Not Registered! Researchers Hongchuan Xin (Fifth Researcher), (Fourth Researcher), (Third Researcher), (Second Researcher), Sadegh Rostamnia (First Researcher)