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Abstract: The synthesis and characterization of a new type of a highly conjugated heterocyclic π‐chromophore, consisting of a central triphenylene core fused with three perylene monoimide units (star‐shaped molecules), is described. By judicious bay functionalization with tert‐butylphenoxy substituents, aggregation was completely prevented by using 1,1,2,2‐tetrachloroethane, allowing for a straightforward purification and, for the very first time, the complete separation of the constitutional isomers by HPLC. Both isomers can be easily distinguished by means of several conventional spectroscopic techniques. Furthermore, we have illustrated the absence of supramolecular aggregates and enhanced processability by noncovalent functionalization of graphene substrates, showing an outstanding homogeneity and demonstrating a different doping behavior in both isomers, making it possible to distinguish them by Raman spectroscopy. [ABSTRACT FROM AUTHOR]

BACKGROUND 1,1,2,2-tetrachloroethane (TeCA) has been generally considered as non-biodegradable under aerobic conditions, while its complete biodegradation was reported with microbial consortia growing anaerobically. This study describes TeCA aerobic co-metabolic degradation by the propanotroph Rhodococcus aetherivorans strain TPA isolated from a TeCA-degrading consortium. RESULTS R. aetherivorans TPA was able to grow on aliphatic hydrocarbons from propane to pentane and on gaseous n-alkane metabolic intermediates. The Michaelis-Menten model allowed a satisfactory fit of the TPA propane utilization rates under resting cell conditions, while the TeCA degradation rates were successfully interpolated with Andrew's inhibition model. A significant propane-TeCA mutual inhibition was observed, although the results did not allow distinguishing between competitive and non-competitive inhibition. Among different bioreactor options for the on-site bioremediation of TeCA-contaminated groundwater, a single suspended-cell continuous stirred-tank reactor (CSTR) appeared to be the optimal one. CONCLUSIONS This study provides for the first time the kinetic and microbiological characterization of a bacterial strain capable of degrading TeCA under aerobic conditions. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The development and validation of a novel kinetic model for the chlorination of 1,2-dichloroethane to ultimately hexachloroethane catalyzed by blue light are presented. A factor ( X m) related to the chlorination depth was introduced into the kinetics model, and the results showed that the dynamic features of the photo-chlorination are better predicted by the modified model than by the conventional one. Furthermore, to enhance the selectivity towards tetrachloroethane and pentachloroethane, a novel reactive distillation with side-reactor configuration (SRC) for the photo-chlorination process was proposed. In order to demonstrate the technical feasibility of the process, semi-batch SRC experiments on the laboratory scale were carried out. Up to 96.5 wt % of tetrachloroethane and pentachloroethane with molar ratios varying from 7 to 0.7 over time were obtained in the bottom product. [ABSTRACT FROM AUTHOR]

The host-guest chemistry of cycloparaphenylenes (CPPs) of different sizes is described. [ n]CPPs ( n=5, 6, 7, 8, and 10) selectively interact with [ n+5]CPPs, forming complexes [ n+5]CPP⊃[ n]CPP, which are the shortest double-walled armchair carbon nanotubes. The size selectivity is dictated by the difference in diameters of the CPPs (that is, 0.34-0.35 nm), which maximizes attractive van der Waals interactions. Theoretical calculations suggest that the orbital energies of the CPPs become perturbed upon complex formation, and orbital mixing between the two CPPs is predicted for large CPP pairs. The association constants in 1,1,2,2-[D2]tetrachloroethane, estimated by 1H NMR titration, are approximately 103 mol L−1 at 50 °C. Van't Hoff plot analysis reveals that complexation is driven mainly by entropy owing to desolvation of the CPPs. [13]CPP also forms a complex with [4]cyclo-2,7-pyrenylene ([4]CPY), which is a π-extended [8]CPP. Theoretical calculations suggest that the formation of [13]CPP⊃[4]CPY is more exothermic than that of [13]CPP⊃[8]CPP. A ternary complex, [15]CPP⊃[10]CPP⊃C60, is also formed by mixing [15]CPP and [10]CPP⊃C60. [ABSTRACT FROM AUTHOR]

A low‐cost, chlorinated hydrocarbon solvent, 1,1,2,2‐tetrachloroethane (TeCA), is used as an effective additive for the triarylamine‐based organic hole‐transport material, Spiro‐OMeTAD, which is successfully applied in highly efficient solid‐state dye‐sensitized solar cells. A record power conversion efficiency of 7.7% is obtained by using the donor (D)‐π‐acceptor (A)‐dye, LEG4, in combination with the new method of TeCA‐doping of the hole‐transporting material Spiro‐OMeTAD. [ABSTRACT FROM AUTHOR]

Reaction of the rigid ligand 2,4,5,6-tetrachloro-1,3-benzenedicarboxylic acid (1,3-H2BDC-Cl4) with copper(II) nitrate in different solvent systems afforded two new complexes {[Cu(1,3-BDC-Cl4)(DMF)] (H2O)} n ( 1) and {[Cu(1,3-BDC-Cl4)(H2O)3] (dioxane) ·(H2O)} n ( 2), which were fully characterized by elemental analysis, IR spectroscopy, as well as single crystal and powder X-ray diffiraction techniques. Single-crystal X-ray diffraction reveals that complexes 1 and 2 crystallize in different space groups P21/ m and Pbca, respectivly. Compound 1 shows a two-dimensional (2D) (4,6)-connected layered network constructed by the connectivity between one-dimensional (1D) [-Cu-DMF-COO-] n chains and tetrachlorinated backbones of 1,3-BDC-Cl4, which is further assembled to generate a three-dimensional (3D) supramolecular framework through intermolecular O-H ···O and O-H ···Cl hydrogen-bonding interactions. Compound 2 features a 2D 4-connected sql coordination net formed by 1D [Cu-H2O] n chains and 1,3-BDC-Cl4 spacers, which is further extended into a 3D supramolecular network by multiple O-H ···O hydrogen-bonding interactions. The different structural features of the two compounds suggest that the choice of solvent systems should play a key role in the process of assembly. Their thermal and fluorescence properties were also investigated. [ABSTRACT FROM AUTHOR]

ZVI-Clay is an emerging remediation approach that combines zero-valent iron (ZVI)-mediated degradation and in situ stabilization of chlorinated solvents. Through use of in situ soil mixing to deliver reagents, reagent-contaminant contact issues associated with natural subsurface heterogeneity are overcome. This article describes implementation, treatment performance, and reaction kinetics during the first year after application of the ZVI-Clay remediation approach at Marine Corps Base Camp Lejeune, North Carolina. Primary contaminants included trichloroethylene, 1,1,2,2-tetrachloroethane, and related natural degradation products. For the field application, 22,900 m3 of soils were treated to an average depth of 7.6 m with 2% ZVI and 3% sodium bentonite (dry weight basis). Performance monitoring included analysis of soil and water samples. After 1 year, total concentrations of chlorinated volatile organic compounds (CVOCs) in soil samples were decreased by site-wide average and median values of 97% and >99%, respectively. Total CVOC concentrations in groundwater were reduced by average and median values of 81% and >99%, respectively. In several of the soil and groundwater monitoring locations, reductions in total CVOC concentrations of greater than 99.9% were apparent. Further reduction in concentrations of chlorinated solvents is expected with time. Pre- and post-mixing average hydraulic conductivity values were 1.7 × 10−5 and 5.2 × 10−8 m/s, respectively, indicating a reduction of about 2.5 orders of magnitude. By achieving simultaneous contaminant mass depletion and hydraulic conductivity reduction, contaminant flux reductions of several orders of magnitude are predicted. [ABSTRACT FROM AUTHOR]

The excited-state intramolecular proton-transfer-induced charge transfer of semirigid polyquinoline (PQH) is explored in 1,1,2,2-tetrachloroethane (TCE) and N-methyl-2-pyrrolidinone (MP) using picosecond time-resolved fluorescence spectroscopy. Reaction mechanisms are found to depend on the rotational conformations of PQH at the moment of excitation; whereas the trans-enolic form does not undergo intramolecular proton transfer within its excited-state lifetime, the cis-enolic form does within 15 ps to form a tautomeric zwitterion species. While the subsequent intramolecular charge transfer of the zwitterionic species to yield a tautomeric keto species takes place on time scales of 25 ps in TCE ( ε = 8.50) and 62 ps in MP ( ε = 32.55), its reverse reaction is also followed on time scales of 28 ps in TCE and 20 ps in MP. The lack of a kinetic isotope effect in both forward and reverse charge-transfer reactions support our proposed mechanisms. [ABSTRACT FROM AUTHOR]

The article presents a study on the melt rheological characteristics of a triblock polymer made of poly(tetramethylene oxide) (PTMO) soft segment and aramide hard segment. In the study, a capillary Ubbelohde OC was used to identify the inherent viscosity of the polymers mixed with phenol-1,1,2,2-tetrachloroethane. The parallel-plate and capillary flow technique were used to calculate the activation energy of the polymer.

Two strictly anaerobic bacterial strains were isolated from contaminated groundwater at a Superfund site located near Baton Rouge, LA, USA. These strains represent the first isolates reported to reductively dehalogenate 1,2,3-trichloropropane. Allyl chloride (3-chloro-1-propene), which is chemically unstable, was produced from 1,2,3-trichloropropane, and it was hydrolysed abiotically to allyl alcohol and also reacted with the sulfide- and cysteine-reducing agents in the medium to form various allyl sulfides. Both isolates also dehalogenated a variety of other vicinally chlorinated alkanes (1,2-dichloropropane, 1,2-dichloroethane, 1,1,2-trichloroethane, 1,1,2,2-tetrachloroethane) via dichloroelimination reactions. A quantitative real-time PCR (qPCR) approach targeting 16S rRNA genes indicated that both strains couple reductive dechlorination to cell growth. Growth was not observed in the absence of hydrogen (H2) as an electron donor and a polychlorinated alkane as an electron acceptor. Alkanes containing only a single chlorine substituent (1-chloropropane, 2-chloropropane), chlorinated alkenes (tetrachlorothene, trichlorothene, cis-dichloroethene, trans-dichloroethene, vinyl chloride) and chlorinated benzenes (1-chlorobenzene and 1,2-dichlorobenzene) were not dechlorinated. Phylogenetic analysis based on 16S rRNA gene sequence data showed these isolates to represent a new lineage within the Chloroflexi. Their closest previously cultured relatives are ‘Dehalococcoides’ strains, with 16S rRNA gene sequence similarities of only 90%. [ABSTRACT FROM AUTHOR]

The article discusses research wherein rubber concrete composed from a rubber solution was utilized as a means for solving the environmental problems of waste tires. Waste tire scrap dissolved in a solvent mixture of tetrachloroethane and methylene chloride was used to prepare the solution. The elastic rubber concrete was manufactured through mold processing that incorporated the rubber solution and aggregates. The solvent was extracted from this mixture of solution and aggregates by carbon dioxide supercritical fluid. Alterations in outdoor conditions did not change the mechanical properties of the material.

In the title complex, [Zn(C48H36N4O4)] C2H2Cl4, the ZnII ion is located on an inversion centre and in an approximately square-planar coordination environment. The tetrachloroethane solvent lies across an inversion centre at the mid-point of the CC bond. Porphyrin-porphyrin and porphyrin-solvent contacts are dominated by CH⋯π and CH⋯O interactions, resulting in the formation of a clathrate-like structure. One benzene ring and its methoxy substituent are disordered over two positions, with site occupancies of 0.824 (2) and 0.176 (2). In addition, two symmetry-equivalent Cl atoms of the tetrachloroethane solvent also exhibit positional disorder, with site occupancies of 0.635 (2) and 0.365 (2). [ABSTRACT FROM AUTHOR]

Two 11.7-m³ experimental controlled release systems (ECRS), packed with sandy model aquifer material and amended with tetrachloroethene (PCE) dense nonaqueous phase liquid (DNAPL) source zone, were operated in parallel with identical flow regimes and electron donor amendments. Hydrogen Releasing Compound (Regenesis Bioremediation Products, Inc., San Clemente, California), and later dissolved lactate, served as electron donors to promote dechlorination. One ECRS was bioaugmented with an anaerobic dechlorinating consortium directly into the source zone, and the other served as a control (biostimulated only) to determine the benefits of bioaugmentation. The presence of halorespiring bacteria in the aquifer matrix before bioaugmentation, shown by nested polymerase chain reaction with phylogenetic primers, suggests that dechlorinating catabolic potential may be somewhat widespread. Results obtained corroborate that source zone reductive dechlorination of PCE is possible at near field scale and that a system bioaugmented with a competent halorespiring consortium can enhance DNAPL dissolution and dechlorination processes at significantly greater rates than in a system that is biostimulated only. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Liver fibrosis is a prelude of liver cirrhosis. Currently the molecular mechanism of liver fibrosis is not clear. The purpose of this study is to screen the abnormally expressed genes of liver fibrosis and to illustrate the changes of Smurf2 expression in the process of liver fibrosis. METHODS: A liver fibrosis model was established in rats by injection of tetrachlormethane (CCl4). A cDNA microarray analysis was performed on the liver at mid-stage of fibrosis. Thereafter, a semi-quantitative RT-PCR, Western blot analysis and immunohistochemistry test were performed for determining Smurf2, Smad2 and SnoN at week 1, 2, 4 and 8 of establishing the liver fibrosis model. RESULTS: Smurf2, FGG, PTAFR, CYP2D6, among others, increased in the fibrosis liver and a semi-quantitative RT-PCR confirmed the reliability of the cDNA microarray analysis. Smurf2 in the liver fibrosis model group was at the same level as that of control group at week 1, but decreased at week 2 and 8 and increased at the week 4. Smad2 increased at week 2 and 8 but increased at week 4. However, Smad2 mRNA increased to the same level at week 4 as that at week 2 and 8. The decrease of Smad2 at week 4 may be due to the enhancement of ubiquitination and proteolytic degradation of Smad2 by the increase of Smurf2. SnoN decreased at week 4 and 8 because of the ubiquitination and degradation caused by Smurf2. The decrease of SnoN may explain the progress of liver fibrosis in spite of the decrease of Smad2 at week 4. CONCLUSION: This study screened the abnormally expressed genes of liver fibrosis and illustrated the changes of Smurf2, Smad2 and SnoN during the process of liver fibrosis. [ABSTRACT FROM AUTHOR]

Develops a protocol to enrich for a tetrachloroethene (PCE)-dechlorinating culture from waste activated sludge and anaerobic digester biosolids. Ways of accomplishing bioremediation technology; Effect of the initial concentration of biomass on the removal of PCE; List of bacterial hosts used for the quantification of bacteriophage.

Phase transfer catalysts (PTCs) can enhance the oxidation of pure DNAPLs using potassium permanganate by facilitating reactions in the organic phase. This study examined the influence of pentyltriphenylphosphonium bromide (PTPP) as a PTC on the rate of permanganate (MnO4-) oxidation of DNAPLs in pure phases and mixtures. Kinetic batch experiments with trichloroethylene (TCE), 1,1,2-trichloroethane (TCA), tetrachloroethylene (PCE), 1,1,2,2-tetrachloroethane (TECA), and their mixtures, (1:1, v/v) were performed in test tubes to assess reaction rates. The disappearance of MnO4- was quantified by capturing digital images pf the tubes. This rapid photographic monitoring approach was validated by comparison with an UV-Vis spectrometer method. The PCE/TCA mixture was selected to examine the impact of relative contents of a component in the binary mixture on the MnO4- disappearance. The comparative rates of MnO4- consumption for pure phases were TCE > TECA > PCE > TCA. PTPP increased MnO4- consumption rates, especially for TCE and TECA as pure, phases. The consumption rates of mixtures without PTPP were lower than those including the pure phases. However, due to their high extraction capability for PTPP-MnO4- ion pairs, TCA and TECA appeared to increase the MnO4- consumption significantly when they were mixed with TCE or PCE, The increase in consumption rates with PTPP was most remarkable with the mixture of PCE and TCA. Chloride concentration showed faster increases for the mixtures with relative PCE contents ranging about 5 % to 90%, maximum at about 50% PCE, than for pure phases of PCE and TCA when the PTC assisted the reactions. The PTC appears to be promising in its ability to increase oxidation rates of DNAPL mixtures. [ABSTRACT FROM AUTHOR]

A two-member co-culture consisting of the dehalor- espiring Desulfitobacterium frappieri TCE1 and the sulphate-reducing Desulfovibrio sp. strain SULF1 was obtained via anaerobic enrichment from soil contaminated with tetrachloroethene (PCE). In this co-culture, PCE dechlorination to cis-dichloroethene was due to the activity of the dehalorespiring bacterium only. Chemostat experiments with lactate as the primary electron donor for both strains along with varying sulphate and PCE concentrations showed that the sulphate-reducing strain outnum- bered the dehalogenating strain at relatively high ratios of sulphate/PCE. Stable co-cultures with both organisms present at similar cell densities were observed when both electron acceptors were sup- plied in the reservoir medium in nearly equimolar amounts. In the presence of low sulphate/PCE ratios, the Desulfitobacterium sp. became the numerically dominant strain within the chemostat co-culture. Surprisingly, in the absence of sulphate, strain SULF1 did not disappear completely from the co- culture despite the fact that there was no electron acceptor provided with the medium to be used by this... [ABSTRACT FROM AUTHOR]

In article number 1402340, Licheng Sun and co‐workers report the use of a lowcost organic solvent, 1,1,2,2‐tetrachloroethane (TeCA), as an additive for the well‐known p‐type organic hole transport material‐2,2',7,7'‐tetrakis‐(N,N‐di‐pmethoxyphenyl‐amine)‐9,9'spiro‐bifluorene (Spiro‐OMeTAD). It is found that this significantly increases the conductivity of Spiro‐OMeTAD‐based semiconducting films. Subsequently, this additive is successfully applied in Spiro‐OMeTAD‐based solid‐state dye‐sensitized solar cells, and a record power conversion efficiency of 7.7% is obtained under one sun illumination. [ABSTRACT FROM AUTHOR]