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Concept: Hydrogen chloride

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Both nitrate and pentachlorophenol (PCP) are familiar pollutants in aqueous environment. This research is focused on the simultaneous removal of nitrate and PCP from simulated contaminated groundwater using a laboratory-scale denitrification reactor packed with corncob as both carbon source and biofilm support. The reactor could be started up readily, and the removal efficiencies of nitrate and PCP reached up to approximately 98 % and 40-45 % when their initial concentrations were 50 mg N/L and 5 mg/L, respectively, after 15-day continuous operation at 10 h of hydraulic retention time (HRT) and 25 °C. Approximately 91 % of PCP removal efficiency was achieved, with 2.47 mg/L of chloride ion release at 24 h of HRT. Eighty-two percent of chlorine in PCP removed was ionized. The productions of 3-chlorophenol and phenol and chloride ion release indicate that the reductive dechlorination reaction is a major degradation pathway of PCP under the experimental conditions.

Concepts: Concentration, Chemistry, Water pollution, Sodium chloride, Ion, Chlorine, Chloride, Hydrogen chloride

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The pressure-temperature phase diagram of ice displays a perplexing variety of structurally distinct phases. In the century-long history of scientific research on ice, the proton-ordered ice phases numbered XIII through XV were discovered only recently. Despite considerable effort, none of the transitions leading from the low-temperature ordered ices VIII, IX, XI, XIII, XIV and XV to their high-temperature disordered counterparts were experimentally found to display the full Pauling entropy. Here we report calorimetric measurements on suitably high-pressure-treated, hydrogen chloride-doped ice XIV that demonstrate just this at the transition to ice XII. Dielectric spectroscopy on undoped and on variously doped ice XII crystals reveals that addition of hydrogen chloride, the agent triggering complete proton order in ice XIV, enhances the precursor dynamics strongest. These discoveries provide new insights into the puzzling observation that different dopants trigger the formation of different proton-ordered ice phases.

Concepts: Crystal, Hydrogen, Ice, Phase, Chlorine, Triple point, Hydrogen chloride, Hydrochloric acid

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An expeditious and cost-efficient method for synthesis of 1-arylcycloprop-2-ene-1-carboxamides was developed. This one-pot protocol involving coupling of amines with acyl chlorides, generated upon treatment of cyclopenylcarboxylic acids with oxalyl chloride, is applicable for the preparation of sensitive products with a reactive, unsubstituted strained double bond.

Concepts: Amine, Chemical synthesis, Ion, Carbonyl, Chlorine, Hydrogen chloride, Acyl chloride, Oxalyl chloride

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A series of scarce N-unsubstituted 2,5-diaryl fulleropyrrolidines as cis isomers could be prepared via the facile one-step reaction of [60]fullerene with N-unsubstituted arylmethanamines promoted by cheap and easily available ferric perchlorate. Nevertheless, the reaction of N-substituted arylmethanamines with [60]fullerene under the same conditions gave different experimental results. N-Methylbenzylamine formed N-methyl 2,5-diphenyl fulleropyrrolidine as a trans isomer, and N,N-dibenzylamine unexpectedly obtained the N-unsubstituted 2,5-diphenyl fulleropyrrolidine as a cis isomer. Intriguingly, high stereoselectivity for all 2,5-diaryl fulleropyrrolidines could be observed although both cis and trans isomers were possibly formed. N-Unsubstituted fulleropyrrolidine could be further converted to N-substituted fulleropyrrolidines under the assistance of an acid chloride or an isocyanate. A possible reaction pathway leading to 2,5-diaryl fulleropyrrolidines is also proposed.

Concepts: Chlorine, Transgender, Hydrogen chloride, Conformational isomerism, Isomer, Scout Motto, Structural isomer

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Simulated ammonium chloride wastewater was treated by a lab-scale bipolar membrane electrodialysis for the generation of HCl and NH3·H2O and desalination. The influence of initial concentration of NH4Cl, current density, salt solution volume, initial concentration of acid and base and membrane stack structure on the yields of HCl and NH3·H2O was investigated. The current efficiency and energy consumption were also examined under different conditions. The results showed that, at the current density of 48 mA/cm(2), the highest concentration of HCl and NH3·H2O with initial concentration of 110 g/L NH4Cl was 57.67 g/L and 45.85 g/L, respectively. Higher initial concentration of NH4Cl was favor to reduce unit energy consumption and increase current efficiency of the BMED system. The membrane stack voltage of BMED increased quickly under constant current when the concentration of NH4Cl contained in the solution of salt compartment was depleted below the “inflection point concentration” about 8000 mg/L. It means that the concentration of NH4Cl below 8000 mg/L was no longer suitable for BMED because of higher energy consumption. The HCl and NH3·H2O concentration increased more quickly following the increase of current density. When increasing the volume of NH4Cl, the concentration of HCl and NH3·H2O also increased. The high initial concentration of acid and base could improve the final concentration of them, while the growth rate was decreased. Compared with the BMED system with three compartments, the growth rate of HCl concentration with the two compartments was higher and its unit energy consumption was lower. It meant that the performance of the BMED system could be improved by optimizing operation conditions. The application feasibility of the generation of HCl and NH3·H2O and desalination of ammonium chloride wastewater by BMED was proved.

Concepts: Ammonia, Water, Hydrogen, PH, Chlorine, Hydrogen chloride, Hydrochloric acid, Chlorides

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Novel strategy of Gemini-like modification has been applied in development of new nonionic surfactants, tea saponin esters, with enhanced surface activity by simple esterification. Tea saponin was treated with acyl chlorides of different chain length and different ratio of tea saponin and acyl chloride under alkaline condition. The structures of tea saponin esters were analysed and confirmed by FT-IR, NMR and ESI-MS. Surface activity investigation revealed that esterification with the chain length of C12 and C14 and the ratio of 1:4 to 1:6 produced superior surface activity compared with tea saponin. The exceptional surface activity of the new surfactants suggested their great potential application in food industry as green surfactants due to their environmental benign nature as well as simple and inexpensive preparation. The strategy of Gemini-like modification will facilitate development of green surfactants based on natural resources.

Concepts: Ratio, Ester, Hydrogen chloride

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The ground electronic state potential energy surface of acryloyl chloride, CH2CHC(O)Cl, has been mapped using an automated transition state search procedure. A total of 174 minima, 527 TSs, and 20 different dissociation channels have been found. Among others, three novel HCl elimination pathways, namely, a five-center mechanism and two three-body dissociations (leading to CO + HCl + HCCH) have been discovered. While the bimodal character of the experimental HCl rotational distributions was previously attributed to the presence of two competing channels, our dynamics simulations show that a single channel, the four-center HCl elimination of CH2ClCHCO following a 1,3-Cl-shift of CH2CHC(O)Cl, displays a bimodal distribution in nearly prefect agreement with the experiment. Overall, our simulation results suggest that, as far as molecular elimination is concerned, this channel dominates in the 193 nm photodissociation of the molecule. The simulations also show evidence of non-IRC dynamics for this channel.

Concepts: Molecule, Transition state, Chemistry, Atom, Kinetic energy, Force, Potential energy, Hydrogen chloride

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Intentional use of mercury (Hg) is an important contributor to the release of Hg into the environment. This study presents the first inventory of material flow for intentional use of Hg in China. The total amount of Hg used in China increased from 803±95 tons in 2005 to its peak level of 1272±110 tons in 2011. Vinyl chloride monomer (VCM) production is the largest user of Hg, accounting for over 60% of the total demand. As regulations on Hg content in products are tightening globally against the background of the Minamata Convention, the total demand will decrease. Medical devices will likely still use a significant amount of Hg and become the second largest user of Hg if no proactive measures are taken. Significant knowledge gaps exist in China for catalyst recycling sector. Although more than half of the Hg used is recycled, this sector has not drawn enough attention. There are also more than 200 tons of Hg that had unknown fates in 2011; very little information exists related to this issue. Among the final environmental fates, landfill is the largest receiver of Hg, followed by air, water and soil.

Concepts: Environment, Chlorine, Recycling, Hydrogen chloride, Polyvinyl chloride, Hydrochloric acid, Vinyl, Vinyl chloride

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The chemistry of the heterobinuclear platinum-iridium complex [PtIr(CO)3(μ-dppm)2][PF6], , dppm = Ph2PCH2PPh2, is described. The reaction of a hydride with gave [HPtIr(CO)2(μ-dppm)2], by displacement of the carbonyl ligand from platinum, while reaction of with dihydrogen, hydrogen chloride or Ph2MeSiH gave the fluxional complex [PtIrH4(CO)(μ-dppm)2][PF6], [PtIrH2Cl2(CO)(μ-dppm)2][PF6], or [PtIrH(SiMePh2)(CO)2(μ-dppm)2][PF6], respectively, by oxidative addition at iridium. Complex reacted, often regioselectively, with several alkynes to give the μ-η(1),η(1) bridging alkyne complexes [PtIr(μ-RCCR')(CO)2(μ-dppm)2][PF6], R = H, R' = Ph, 4-C6H4Me, CO2Me; R = Ph, R' = CO2Me; R = R' = CO2Me. The complex [PtIr(μ-HCC-4-C6H4Me)(CO)2(μ-dppm)2][PF6] reacted reversibly with CO to give [PtIr(μ-HCC-4-C6H4Me)(CO)3(μ-dppm)2][PF6] and [PtIr(CO)3(μ-dppm)2][PF6], . With HCl, [PtIr(μ-HCC-4-C6H4Me)(CO)2(μ-dppm)2][PF6] reacted to give [PtIrHCl(μ-HCC-4-C6H4Me)(CO)2(μ-dppm)2][PF6], by oxidative addition at iridium, and then the alkenylplatinum derivative [PtIrCl{HC[double bond, length as m-dash]CH(4-C6H4Me)}(CO)2(μ-dppm)2][PF6]. [PtIr(μ-HCC-4-C6H4Me)(CO)2(μ-dppm)2][PF6] reacted slowly with dihydrogen to give 4-MeC6H4CH[double bond, length as m-dash]CH2 and [PtIrH4(CO)(μ-dppm)2][PF6]. The complex [PtIr(μ-HCCPh)(CO)2(μ-dppm)2][PF6] is intensely luminescent in solution at room temperature, with features characteristic of a d(8)-d(8) face-to-face complex.

Concepts: Oxygen, Chemical reaction, Hydrogen, Hydrogenation, Ion, Chlorine, Hydrogen chloride, Hydrochloric acid

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High-surface-area mesoprous powders of γ-Al2O3 doped with Cu(2+), Cr(3+), and V(3+) ions were prepared via a modified sol-gel method and were investigated as catalysts for the oxidation of chlorinated organic compounds. The composites retained high surface areas and pore volumes comparable with those of undoped γ-Al2O3 and the presence of the transition metal ions enhanced their surface acidic properties. The catalytic activity of the prepared catalysts in the oxidation of 1,2-dichloroethane (DCE) was studied in the temperature range of 250-400°C. The catalytic activity and product selectivity were strongly dependent on the presence and the type of dopant ion. While Cu(2+)- and Cr(3+)-containing catalysts showed 100% conversion at 300°C and 350°C, V(3+)-containing catalyst showed considerably lower conversion. Furthermore, while the major products of the reactions over γ-alumina were vinyl chloride (C2H3Cl) and hydrogen chloride (HCl) at all temperatures, Cu- and Cr-doped catalysts showed significantly stronger capability for deep oxidation to CO2.

Concepts: Chemical reaction, Hydrogen, Catalysis, Nitrogen, Solid, Chlorine, Hydrogen chloride, Hydrochloric acid