Cyclohexanohemicucurbit[8]uril Inclusion Complexes With Heterocycles and Selective Extraction of Sulfur Compounds From Water

Solid-phase extraction that utilizes selective macrocyclic receptors can serve as a useful tool for removal of chemical wastes. Hemicucurbiturils are known to form inclusion complexes with suitably sized anions; however, their use in selective binding of non-charged species is still very limited. In this study, we found that cyclohexanohemicucurbit[8]uril encapsulates five- and six-membered sulfur- and oxygen-containing unsubstituted heterocycles, which is investigated by single-crystal X-ray diffraction, NMR spectroscopy, isothermal titration calorimetry, and thermogravimetry. The macrocycle acts as a promising selective sorption material for the extraction of sulfur heterocycles, such as 1,3-dithiolane and α-lipoic acid, from water.

Promotion of C-S Bond Scission over Solid Catalytic Sulfides by Aromatics and Nitrogen Heterocycles

The competitive adsorption of aromatics and nitrogen heterocycles on the active sites of solid catalytic sulfides (Ni(Co)-MoS2 dispersed over oxidic carriers) typically causes inhibitory effects during the hydropurification of sulfur heterocycles. Contrary to this typical behavior, we report herein that it is possible to promote the scission of the C-S bond of refractory dibenzothiophene by co?feeding the above compounds during hydropurification over a conventional Ni-MoS2/Al2O3 catalyst. Particularly, we prove that at temperatures between 240 and 300°C and concentrations of dibenzothiophene between 1.0 and 3.7 wt.%, the desulfurization of dibenzothiophene is promoted by increasing its conversion up to 370% when either naphthalene, indole, or quinoline are co-fed to the reaction system. The work highlights the following: (i) lower temperatures and higher concentrations of the sulfur heterocycle enhanced the cleavage of the C-S bond from dibenzothiophene; (ii) it is possible to promote hydropurification reactions regardless of the nature of the of co-reactants; namely: a fused aromatic ring -naphthalene-, or a fused nitrogen heterocycle with a lone pair belonging to the pi-system -quinoline- or not -indole-.<br><p><a></a></p>

Promotion of C-S Bond Scission over Solid Catalytic Sulfides by Aromatics and Nitrogen Heterocycles

The competitive adsorption of aromatics and nitrogen heterocycles on the active sites of solid catalytic sulfides (Ni(Co)-MoS2 dispersed over oxidic carriers) typically causes inhibitory effects during the hydropurification of sulfur heterocycles. Contrary to this typical behavior, we report herein that it is possible to promote the scission of the C-S bond of refractory dibenzothiophene by co?feeding the above compounds during hydropurification over a conventional Ni-MoS2/Al2O3 catalyst. Particularly, we prove that at temperatures between 240 and 300°C and concentrations of dibenzothiophene between 1.0 and 3.7 wt.%, the desulfurization of dibenzothiophene is promoted by increasing its conversion up to 370% when either naphthalene, indole, or quinoline are co-fed to the reaction system. The work highlights the following: (i) lower temperatures and higher concentrations of the sulfur heterocycle enhanced the cleavage of the C-S bond from dibenzothiophene; (ii) it is possible to promote hydropurification reactions regardless of the nature of the of co-reactants; namely: a fused aromatic ring -naphthalene-, or a fused nitrogen heterocycle with a lone pair belonging to the pi-system -quinoline- or not -indole-.<br><p><a></a></p>

Cyclohexanohemicucurbit[8]uril forms inclusion complexes with heterocycles and removes sulfuric guests from water via solid-phase extraction

We found that cyclohexanohemicucurbit[8]uril encapsulates five- and six-membered sulfur- and oxygen-containing unsubstituted heterocycles and can be used as a selective sorption material for the extraction of sulfur-heterocycles like 1,3-dithiolane and α‑lipoic acid from water.

Binding of Heterocycles by Cyclohexanohemicucurbiturils and Solid-Phase Extraction of Sulfur-Containing Heterocycles from Water

Here we report a study on cyclohexanohemicucurbit[8]uril (cycHC[8]) binding of sulfur-, oxygen- and nitrogen-containing heterocycles in both solid state and solution, which is investigated by single crystal X-ray diffraction, NMR spectroscopy, isothermal titration calorimetry, and thermogravimetry. Potential guests include environmental pollutants, hazardous compounds, and bioactive substances. We found that cycHC[8] encapsulates five- and six-membered sulfur- and oxygen-containing unsubstituted heterocycles and can be used as a selective sorption material for the extraction of sulfur-heterocycles from water. Both cycHC[6] and cycHC[8] can remove a substituted heterocycle, α-lipoic acid, from an aqueous solution via the formation of an external complex. The results show that cycHC[<i>n</i>] is a promising reusable sorbent material with the potential to be employed in molecular recognition and highly specific solid-phase extraction of sulfur-heterocycles.

Binding of Heterocycles by Cyclohexanohemicucurbiturils and Solid-Phase Extraction of Sulfur-Containing Heterocycles from Water

Here we report a study on cyclohexanohemicucurbit[8]uril (cycHC[8]) binding of sulfur-, oxygen- and nitrogen-containing heterocycles in both solid state and solution, which is investigated by single crystal X-ray diffraction, NMR spectroscopy, isothermal titration calorimetry, and thermogravimetry. Potential guests include environmental pollutants, hazardous compounds, and bioactive substances. We found that cycHC[8] encapsulates five- and six-membered sulfur- and oxygen-containing unsubstituted heterocycles and can be used as a selective sorption material for the extraction of sulfur-heterocycles from water. Both cycHC[6] and cycHC[8] can remove a substituted heterocycle, α-lipoic acid, from an aqueous solution via the formation of an external complex. The results show that cycHC[<i>n</i>] is a promising reusable sorbent material with the potential to be employed in molecular recognition and highly specific solid-phase extraction of sulfur-heterocycles.

Applications of Ionic Liquids in Gas Chromatography

The environment offers an enormous innovative panorama of prospects intended for the research of novel biodegradable diluents. Regular composites have been lately recycled to formulate the anionic and cationic fraction of RTIL. Numerous applications of ionic liquids have been explored in segregation discipline. Attributable to the extraordinary polarization as well as exceptional current steadiness, IL-centered immobile segments have been applied to resolution of varied series of critically stimulating complexes frequently extremely polar composites using great boiling points plus physical resemblances comprising elongated sequence fatty acids, essential oils, polycyclic aromatic sulfur heterocycles (PASHs) and PCBs. IL-centered immobile segments facilitated the gas chromatography study for effective as well as precise amount of liquid in the industrialized yields for example pharmaceutical as well as petrochemicals complexes.