Nano-ZrO₂ sulfuric acid: a heterogeneous solid acid nano catalyst for Biginelli reaction under solvent free conditions

Abstract

Nano-ZrO2 sulfuric acid [n-ZrO2–SO3H (n-ZrSA)] has been synthesized from the reaction of nano-ZrO2 with chlorosulfonic acid as sulfonating agent.

12‐Tungstosilicic Acid H4[W12SiO40] Over Natural Bentonite as a Heterogeneous Catalyst for the Synthesis of 3,4‐dihydropyrimidin‐2(1H)‐Ones

“…Patil et al recently extensively reviewed usage of different kind of supports as a heterogeneous catalyst for this reaction . A notable solid acid catalysts such as silica sulfuric acid, MCM‐41‐SO 3 H, PS‐PEG‐SO 3 H, Al 2 O 3 /MeSO 3 H, bio‐glycerol‐SO 3 H, Fe 3 O 4 @SBA‐15‐COOH, PPF‐SO 3 H, Fe 3 O 4 /PAA‐SO 3 H, BPMO‐IL‐SO 3 H, SiO 2 ‐Pr‐SO 3 H, nano‐γ‐Fe 2 O 3 ‐SO 3 H, perlite‐SO 3 H, nano‐ZrO 2 ‐SO 3 H, Fe 3 O 4 @SiO 2 ‐PhSO 3 H, SiO 2 ‐phosphonicacid, β‐cyclodextrin‐propylsulfonicacid, ZrO 2 ‐SO 3 H, GO‐SO 3 H, halogenated macroporous sulfonic resin and Fe 3 O 4 @meglumine‐SO 3 H that delivered DHPMs in high yields with good reusability. In spite of exploring the different type of material as a catalyst for this one‐pot condensation reaction, there is still scope to find a novel catalyst system which is easily available and can mitigate the above mentioned problems.…”

Air‐stable zirconium (IV)‐salophen perfluorooctanesulfonate as a highly efficient and reusable catalyst for the synthesis of 3,4‐dihydropyrimidin‐2‐(1H)‐ones/thiones under solvent‐free conditions

“…In show the merit of the present study, the results of using complex 1 for the synthesis of product 5a by reacting benzaldehyde, ethyl acetoacetate, and urea with other homogeneous and heterogeneous catalysts were compared (Table , entries 3–14). According to the obtained results our catalyst shows better catalytic activity with a shorter reaction time using solvent‐free conditions with good recyclability. Apparently, the long fluoroalkyl chain in the sulfonate must be responsible for the hydrophobicity and increasing the catalytic activity.…”

Intraparticle Diffusional versus Site Effects on Reaction Pathways in Liquid‐Phase Cross Aldol Reactions

“…There was no obvious difference in the OH vibrations between plain and propyl sulfonic acid‐functionalized samples. The ν(OH) band of free ‐SO 3 H groups is around 2700–3600 cm −1 ; presumably, strong H‐bonding prevented distinction of these vibrations.…”