Synergistic effect of arsenic removal from petroleum condensate via liquid-liquid extraction: Thermodynamics, kinetics, DFT and McCabe-Thiele method.

This work presents the purification of petroleum condensate by removing arsenic ions via liquid-liquid extraction (LLE). Influence of pure and synergistic extractants is investigated. In terms of the practicability, following parameters are examined: the type of extractant, operating time, and temperature. Response surface methodology is used to design parameters such as organic-aqueous ratio and extractant concentration. Under optimal conditions; a mixture of 1 mol/L HCl and 0.02 mol/L thiourea with an organic/aqueous ratio of 1:4 at 323.15 K for 60 min, the extraction of arsenic reached 78.2 %. Further, batch simulation via two-stage counter-current extraction, and estimation by McCabe-Thiele diagram proved to be enhanced arsenic extraction to 95.3 %. Analysis by FTIR show that arsenic ions in petroleum condensate are formed as triphenylarsine compound ((C6H5)3As). The process of arsenic removal proved to be zero-order endothermic, irreversible and spontaneous reaction. The results obtained from the density functional theory (DFT) confirm that arsenic ions react with the synergistic extractant: effectively forming a covalent bond (As-S).

Evaluation of Ar tagging toward the vibrational spectra and zero point energy of X-HOH, X-DOH, and X-HOD, for X = F, Cl, Br.

In this study, we theoretically evaluated the effect of argon tagging toward the binding energy and vibrational spectra of water halide anion complexes Ar.X-HOH, Ar.X-HOD, and Ar.X-DOH (X = F, Cl, Br). The ionic hydrogen bond (IHB) OH stretching mode was calculated to have a strong peak in the vibrational spectra, and coupling to intermolecular modes as well as bending modes was observed as combination bands and Fermi resonances. We found that the argon tagging affected the IHB OH stretching peak position in Ar.F-H2O, but not in Ar.Cl-H2O and Ar.Br-H2O. Furthermore, D-binding is favored for Cl and Br based on zero point energies, but for F our calculated zero point energies did not show a preference between H- and D-binding. We show that the competition of the energy lowering in the zero point energy of the anharmonic IHB OH (OD) stretching mode versus the intermolecular out-of-plane IHB OH (OD) wagging mode is important for determining the preference between H- and D-binding for these monohydrated halide clusters. We also found that for X-HOD the HOD bending fundamental peak is blue shifted compared to bare HOD, but is redshifted for F-DOH.

Chromanones and aryl glucoside analogs from the entomopathogenic fungus Aschersonia confluens BCC53152.

Six new compounds [ascherlactones A (1) and B (2), ascherchromanone A (3), phenethyl 4'-O-methylglucoside (8), 4'-O-methylpleoside (10), and 4'-O-methyltorachrysone 8-O-glucoside (11)] and one naturally new compound [4'-O-methyl-ß-d-benzylglucoside (9)] together with fourteen known compounds, including paecilodepsipeptides A (5), B (7), and D (4), conoideocrellide A (6), eugenin (12), 5-hydroxy-2,3-dimethyl-7-methoxychromone (13), (S)-1-phenyl-1,2-ethanediol (14), (2S)-l-3-phenyllactic acid (15), papuline [or (2S)-l-3-phenyllactic acid methyl ester, 16], 2'-epi terpendole A (17), terpendoles C (18) and D (19), cholic acid, and zeorin were isolated from the entomopathogenic fungus Aschersonia confluens BCC53152. Their chemical structures were elucidated on the basis of NMR spectroscopic and mass spectrometric analyses. The absolute configurations were determined by using the evidence from NOESY correlations, chemical means, optical rotation values together with comparison of ECD spectroscopic data with the calculated ECD spectra. The plausible biosynthetic pathway of compounds 1-3 was also proposed. Moreover, antimicrobial activity such as antimalarial, antitubercular, antifungal, and antibacterial activities and cytotoxicity against cancerous (MCF-7, KB, and NCI-H187) and non-cancerous (Vero) cells of the isolated compounds were evaluated.

Antimicrobial drimane - phthalide derivatives from Hypoxylon fendleri BCC32408.

Fourteen new compounds including thirteen drimane - phthalide derivatives (fendlerals A - C, fendlerins A - D, fendlerols A - B, fendleric acids A - C, fendlerinine G) and one terphenyl derivative (fendleryl E) along with eight known compounds, fendlerinine A, rickenyls C - D, fendleryls C - D, atromentin, tetramethyl atromentin, and (±)-microsphaerophthalide F, were isolated from the wood fungus Hypoxylon fendleri BCC32408. Compared with the prior work, the results indicated the agitation effect on the production of bioactive drimane - phthalides. The chemical structures were determined based upon spectroscopic analyses and the absolute configurations were verified by comparison of the ECD spectral data with the calculated ECD spectra of the related compounds. Compounds 1-3 exhibited antimicrobial activity against Plasmodium falciparum (IC50 4.15-4.39 µM), Colletotrichum capsici (MIC 6.25-12.5 µg/mL), and Bacillus cereus (MIC 1.56-3.13 µg/mL). All tested compounds displayed broad cytotoxicity against cancerous (MCF-7, KB, and NCI-H187) and non-cancerous (Vero) cells.

Colorimetric N-butyl-3,6-diamidecarbazole-based chemosensors for detection of fluoride and cyanide anions.

Colorimetric sensors from N-butyl-3,6-disubstituted carbazole derivatives containing nitroazobenzene (1) and nitrobenzene (2) were designed, synthesized and compared for their anion sensing ability. Computational simulations were undertaken to determine the optimum geometry of 1. Anion sensing studies revealed that selectivity in anion detection depended on the polarity of solvent, acidity of binding unit and basicity of the anion. The ability to sense via naked eye observations using the strong basic anions (F- and CN-) for both sensors arises from a deprotonation process at the binding sites attributed to the intramolecular charge transfer transition at the sensory unit. The discrimination of F- from CN- has been achieved by the optimization of solvent polarity. Sensor 1 offers a promising property over sensor 2 with a lower detection limit, a few of anion interference and higher stability.

Theoretical calculation of the vibrational state dependent photodetachment spectra of X-H2O, X = F, Cl, Br.

Vibrational spectra of X-H2O (X = F, Cl, Br) were simulated using full dimensional vibrational calculations using quantum chemistry potential energy surfaces. Furthermore, utilizing the reflection approximation, we simulated the photodetachment spectra obtained from different vibrational excited states. From these spectra, we can observe changes in the hydrogen bond interaction between the anion and the neutral XH2O system. Notably, for F-H2O, the excitation of the ionic hydrogen bonded (IHB) OH stretching vibration generates a large tail on the low energy side of the photodetachment spectra compared to the detachment from the zero-point vibration state. This shows that the IHB OH stretching vibration of F-H2O causes charge delocalization from F- to the oxygen atom in H2O, and that the photodetachment from FHOH- occurs at lower energies.

Crystal structures of tetra-methyl-ammonium (2,2'-bi-pyridine)-tetra-cyanidoferrate(III) trihydrate and poly[[(2,2'-bi-pyridine-κ(2) N,N')di-µ2-cyanido-dicyanido(µ-ethyl-enedi-amine)(ethyl-enedi-amine-κ(2) N,N')-cadmium(II)iron(II)] monohydrate].

The crystal structures of the building block tetra-methyl-ammonium (2,2'-bi-pyridine-κ(2) N,N')tetra-cyanidoferrate(III) trihydrate, [N(CH3)4][Fe(CN)4(C10H8N2)]·3H2O, (I), and a new two-dimensional cyanide-bridged bimetallic coordination polymer, poly[[(2,2'-bi-pyridine-κ(2) N,N')di-µ2-cyanido-dicyanido(µ-ethyl-enedi-amine-κ(2) N:N')(ethyl-enedi-amine-κ(2) N,N')cadmium(II)iron(II)] monohydrate], [CdFe(CN)4(C10H8N2)(C2H8N2)2]·H2O, (II), are reported. In the crystal of (I), pairs of [Fe(2,2'-bipy)(CN)4](-) units (2,2'-bipy is 2,2'-bi-pyri-dine) are linked together through π-π stacking between the pyridyl rings of the 2,2'-bipy ligands to form a graphite-like structure parallel to the ab plane. The three independent water mol-ecules are hydrogen-bonded alternately with each other, forming a ladder chain structure with R 4 (4)(8) and R 6 (6)(12) graph-set ring motifs, while the disordered [N(CH3)4](+) cations lie above and below the water chains, and the packing is stabilized by weak C-H⋯O hydrogen bonds. The water chains are further linked with adjacent sheets into a three-dimensional network via O-H⋯O hydrogen bonds involving the lattice water mol-ecules and the N atoms of terminal cyanide groups of the [Fe(2,2'-bipy)(CN)4](-) building blocks, forming an R 4 (4)(12) ring motif. Compound (II) features a two-dimensional {[Fe(2,2'-bipy)(CN)4Cd(en)2]} n layer structure (en is ethyl-enedi-amine) extending parallel to (010) and constructed from {[Fe(2,2'-bipy)(CN)4Cd(en)]} n chains inter-linked by bridging en ligands at the Cd atoms. Classical O-H⋯N and N-H⋯O hydrogen bonds involving the lattice water mol-ecule and N atoms of terminal cyanide groups and the N-H groups of the en ligands are observed within the layers. The layers are further connected via π-π stacking inter-actions between adjacent pyridine rings of the 2,2'-bipy ligands, completing a three-dimensional supra-molecular structure.