Mercury is a major toxic metal ranking top in the Toxic Substances List. Cinnabar (contains mercury sulfide) has been used in traditional medicines for thousands years as an ingredient in various remedies, and 40 cinnabar-containing traditional medicines are still used today. Little is known about toxicology profiles or toxicokinetics of cinnabar and cinnabar-containing traditional medicines, and the high mercury content in these Chinese medicines raises justifiably escalations of public concern. This minireview searched the available database of cinnabar, compared cinnabar with common mercurials, such as mercury vapor, inorganic mercury, and organic mercury, and discusses differences in their bioavailability, disposition, and toxicity. The analysis showed that cinnabar is insoluble and poorly absorbed from the gastrointestinal tract. Absorbed mercury from cinnabar is mainly accumulated in kidney, resembling the disposition pattern of inorganic mercury. Heating cinnabar results in release of mercury vapor, which in turn can produce toxicity similar to inhalation of these vapors. The doses of cinnabar required to produce neurotoxicity are thousands 1000 times higher than methyl mercury. Following long-term use of cinnabar, renal dysfunction may occur. Dimercaprol and succimer are effective chelation therapies for general mercury intoxication including cinnabar. Pharmacology studies of cinnabar suggest sedative and hypnotic effects, but the therapeutic basis of cinnabar is still not clear. In summary, cinnabar is chemically inert with a relatively low toxic potential when taken orally. In risk assessment, cinnabar is less toxic than many other forms of mercury, but the rationale for its inclusion in traditional Chinese medicines remains to be fully justified.

Although manganese oxide (MnO2) exhibits excellent activity in various oxidation reactions, especially for volatile organic compound oxidation, the origin of the catalytic activity remains ambiguous and controversial. In this study, four types of MnO2 catalysts with crystal phases corresponding to α-, β-, γ-, and δ-MnO2 were synthesized, and their catalytic properties in HCHO and C6H6 oxidation were studied. α- and γ-MnO2 were found to possess much better activity for C6H6 oxidation than δ- and β-MnO2 catalysts, whereas δ-MnO2 exhibited the best performance for HCHO oxidation as compared with other types of MnO2. Three kinds of oxygen species were discriminated based on their Mn–O bond strength and reducibility. By quantitatively correlating the amount of specific oxygen species with the reaction rates, the catalytic roles of different oxygen species in HCHO and C6H6 oxidation were clarified. With the assistance of isotopic labeling studies, the participation of oxygen species in C6H6 oxidationwhich followed a Mars–van Krevelen mechanismwas illuminated.

We report herein a mild and catalytic phosphonofluorination of unactivated alkenes. With catalysis by AgNO3, the condensation of various unactivated alkenes with diethyl phosphite and Selectfluor reagent in CH2Cl2/H2O/HOAc at 40 °C led to the efficient synthesis of β-fluorinated alkylphosphonates with good stereoselectivity and wide functional group compatibility. A mechanism involving silver-catalyzed oxidative generation of phosphonyl radicals and silver-assisted fluorine atom transfer is proposed.

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Adsorptive removal of thiophenic compounds from oils by commercial coconut-based activated carbon (AC) and modified AC samples was studied systematically in a batch-type adsorption system. The modified AC samples were obtained by treating the commercial AC sample using 65 wt % concentrated nitric acid (HNO 3 ) at different temperatures (30−120 °C). The effects of the modification temperature on morphology, pore structure, and surface chemistry of the AC samples were analyzed and compared. It has been found that oxidation with concentrated HNO 3 at ambient conditions removes inorganic components or ashes of ca. 50% in the AC sample, produces carboxyl functional groups on the AC surface, and introduces high volume micropores with sizes around 0.54 nm. The effects of pore structure and surface features on adsorptive capability for the thiophenic compounds were investigated in detail. The results show that the as-received AC sample is able to adsorb the bigger size sulfur compounds. The adsorptive removal efficiency for the sulfur compounds decreases in the order of 4,6dimethyldibenzothiophene > dibenzothiophene > benzothiophene > thiophene. The modified AC samples can adsorb more thiophene and benzothiophene molecules, but this is not the case for dibenzothiophene and 4,6-dimethyldibenzothiophene molecules. On the basis of the results obtained, it was proposed that the pore structure and surface chemistry of the AC as well as frontier orbital energies of the thiophenic compounds and the AC samples govern the adsorption of these species on the surface of AC.

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