Modeling adsorption of organic compounds (OCs) by carbon nanotubes (CNTs): role of OCs and CNTs properties on the linear solvation energy relationships (LSER)

This study evaluated a comprehensive database for the adsorption of polar and nonpolar organic compounds (OCs) by carbon nanotubes (CNTs) and to use the linear solvation energy relationship (LSER) technique for developing predictive adsorption models of OCs by multi-walled carbon nanotubes (MWCNTs) and single-walled carbon nanotubes (SWCNTs). The results showed that coefficient of determinations (R2) values for all compounds are higher variability in the 200 g/mol molecular weight cutoff (74–99%). When the molecular weight cutoff of all OCs is higher than 200 g/mol, the trend of their R2 values is decreased (less than 70%). Among all adsorbate descriptor coefficients, V and B terms are the most significant descriptors (p values ≤ 0.05) in LSER equations for adsorption of low molecular weight polar and nonpolar OCs by both CNTs. Besides, KOW normalization of all Kd values did not have significant impact on the regression of the LSER model, indicating that hydrophobic interactions are not sole mechanism for the adsorption of OCs on CNTs. Lastly, SWCNTs exhibited higher polar OCs uptake than MWCNTs, which was attributed to more polar surface of SWCNTs as suggested by its high oxygen content (%10).

Synthesis of a new organic probe 4-(4 acetamidophenylazo) pyrogallol for spectrophotometric determination of Bi(III) and Al(III) in pharmaceutical samples

A modern development discusses the synthesis and validity of simple, sensitive, and versatile spectrophotometric methods for Bi(III) and Al(III) determination in pharmaceutical formulations have been conducted. In the present paper, 4-(4 acetamidophenylazo) pyrogallol has been synthesized as a new organic compound, 4-APAP, by coupling pyrogallol in a regulated pH medium with diazotized p-aminoacetanilide. 4-APAP was identified by methods of FT-IR, 1H-NMR, 13C-NMR, and thermal analysis (thermogravimetry and differential scanning calorimetry). Solvatochromic activity was also studied in solvents with different polarities. The Kamlet and Taft linear solvation energy relationship was used to correlate shifts in UV-Visible spectra of 4-APAP with Kamlet-Taft parameters (α, β, and π*). The optimum assay conditions showed linearity from 0.3–13 to 0.5–11 μg·mL−1 for Bi(III) and Al(III), respectively. Molar absorptivity values were 3.365 × 104 and 0.356 × 104 L·mol−1·cm−1 for Bi(III) and Al(III), with similar Sandell's sensitivity measures of 0.006 and 0.008 μg·cm−2. Detection limits and quantification limits were 0.013 and 0.043 μg·mL−1 for Bi(III), respectively, and 0.018 and 0.059 μg·mL−1 for Al(III) with the relative standard deviation for determination of both metal ions using 4-APAP probe being <2.0%. The validity, accuracy, and efficiency of the approaches were demonstrated by the determination of Bi(III) and Al(III) in different formulations.

Ionic liquids: “normal” solvents or nanostructured fluids?

This review provides an overview of the literature from 2010 to the present day, covering the effect of ionic liquids (ILs) on organic reactivity. Two major viewpoints emerge, based on linear solvation energy relationships or nanostructure of ILs.

Linear solvation energy relationship development for adsorption of synthetic organic compounds by carbon nanomaterials: an overview of the last decade

The LSER models for adsorption of SOCs by CNMs profoundly depend on compound properties, adsorbent characteristics and the background solution.