Sulfonamide-Functionalized Porous Organic Framework as an Efficient Heterogeneous Acid Catalyst for One-Pot Preparation of 1,8-Dioxooctahydroxanthenes

Simultaneous removal of heavy metal ions by a sulfonic acid-functionalized melamine-based covalent organic framework: optimization by response surface methodology

“…The synthesis of a pure COF was performed by a simple solvothermal method according to the previous reports. 18,36 In brief, 3.73 mmol (0.47 g) of melamine and 5.59 mmol (0.75 g) of terephthalaldehyde were dissolved in 23 mL of DMSO in a high-pressure Teflon-lined stainless-steel autoclave and kept in an oven at 180 1C for 14 h. After cooling the autoclave to room temperature, the impure precipitate was collected and then thoroughly washed with excess acetone, dichloromethane and distilled water (30 mL Â 2) to remove unreacted organic materials and probable residual solvent present in the mixture. Finally, the white powder of the melamine-based COF was dried in an oven at 60 1C for 12 h.…”

“…COF@SO 3 H was prepared according to our previous report. 18,36 In this regard, after the successful preparation of the pure COF via a solvothermal method, it was subsequently sulfonated via chlorosulfonic acid addition (Scheme 1).…”