The calixarenes

SBA-15 mesoporous silica coated with macrocyclic calix[4]arene derivatives: Solid extraction phases for heavy transition metal ions

“…Solidstate 29 Si magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectra were recorded on the same spectrometer. Fourier transform infrared (FT-IR) spectroscopy was performed with a Perkin-Elmer Spectrum 2000 spectrometer.…”

“…This system can decrease the limitation concerning relatively slow diffusion of the analyte in the matrix owing to the highly periodic mesoporosity in SBA-15. The multiple characterization techniques, such as XRD, nitrogen adsorption, TEM, FT-IR and solidstate 29 Si NMR, as well as TG, indicate that the calix [4]arene derivatives have been well-anchored on the surface of SBA-15 to generate a new class of hybrid calix [4]arene derivatives-based mesoporous silica materials possessing uniform framework mesoporosity. Furthermore, the functionalized mesoporous SBA-15 with calix [4]arene derivatives have demonstrated their high affinity and strong trap capacity for metal ions, including Hg 2+ , Pb 2+ and Cd 2+ , etc., which may develop HTM ions extraction phase for environmental protection applications.…”

“…Since their discovery as by-products in the phenol-formaldehyde condensation to prepare bakelites [28,29], the calixarenes have gained much attention for their application as both surfactants and chemoreceptors. Calixarenes are characterized by a wide upper rim and a narrow lower rim and a central annulus.…”

Solvent Extraction of Rare Earth and Precious Metals with Quaternary Ammonium Type of Calix[4]arene

“…Organic phase was prepared by diluting TEQAC [4]Non or TEQAC [1]Non in chloroform to 5 mM. For aqueous phase, each chloride salt of rhodium, palladium, gold, platinum was dissolved in appropriate concentrations of hydrochloric acid.…”

“…A number of studies have been conducted on such properties of calixarenes and a number of studies of the specific behavior have been reviewed. [1,2] The authors have focused on the use of calixarene compounds as solvent extraction reagents for metal separation. In our previous works, cation exchange types of calixarene compounds have been prepared by introducing adequate cation exchangeable and neutral groups to phenolic oxygens, and the specific extraction behavior has been reported.…”