Nicolet nexus ftir

All reagents and solvents were purchased from Sigma-Aldrich and used without further purification. Compound 2 was prepared as described in [22 (link)]. Column chromatography was carried out on silica gel 60 (0.040–0.063 mm, 230–400 mesh, Fluka). ¹H and ¹³C NMR spectra were recorded at room temperature (291 K) in CDCl₃ on a Bruker ARX 600 MHz (600 MHz for ¹H and 151 MHz for ¹³C). Chemical shifts are in ppm and coupling constants in Hz. Fourier transform-infrared (FT-IR) spectroscopy data were obtained from Thermo Nicolet Nexus FT-IR. The spectra were recorded from an accumulation of 32 scans in the range of 4000~400 cm⁻¹. Mass spectra were recorded on Varian 500-MS LC Ion Trap. Elemental analyses were performed in the Microanalytical Laboratory of the Faculty of Chemistry, University of Lodz.

The diffuse reflectance infrared Fourier transform (DRIFT) spectra were recorded on the Thermo Nicolet Nexus FT-IR at 4 cm⁻¹ resolution, using the special thermal vacuum adapter “Collector II” at 100 °C. The samples were mixed with KBr (1:20).
The nitrogen adsorption/desorption isotherms for all the samples were measured on the “Kelvin-1042” adsorption analyzer (Costech Microanalytical). Before the measurements, the samples were degassed at 110 °C, in the helium atmosphere. The BET specific surface area [13 (link)] was evaluated in the 0.03–0.35 range of relative pressures.
The content of amino groups was determined by acid-base titration. Batches of the samples (0.05 g) were treated with a 0.1 M HCl solution (20 mL) for 6 h. The precipitates were removed by a magnet, and supernatant was titrated with 0.1 M NaOH, in the presence of indicator (methyl orange) [14 ]. Concentration of the amino groups was determined from the difference between the content of protons in solution before and after sorption.