Presence Of Carbon Tetrachloride Research Articles

Long-term effectiveness and sustainability of EHC remediation in carbon tetrachloride-contaminated groundwater: Mechanistic understanding and practical applications

The presence of carbon tetrachloride in groundwater raises concerns for human health and the environment. Thus, there is an urgent need for a faster and more efficient groundwater remediation method. Our study found that the EHC remedial agent can achieve promising pilot remediation results quickly, as demonstrated in laboratory tests. During the pilot test, the contaminated groundwater was subjected to injection with the EHC remedial agent using in-situ high-pressure rotary jet technology. It was observed that indicators such as alkalinity and SO42− can signify the occurrence of biological reduction, with the presence of ZVI significantly shortening the beginning time of biological action within the EHC. The pilot test results reveal that the initial four days following the injection of the EHC witnessed only chemical reduction, with chemical and biological reduction coexisting from day 4 to day 45. Post the 45-day mark, the removal of contaminants solely relied on biological reduction. While chemical reduction displayed a rapid rate but limited duration, insufficient for ensuring long-term effectiveness in the remediation process, bioremediation offered sustained efficacy for continuous contaminant reduction. These findings signify a more eco-friendly and efficient approach to groundwater remediation, offering both human health and environmental benefits.

Pharmacokinetic assessment of rifampicin and des-acetyl rifampicin in carbon tetrachloride induced liver injury model in Wistar rats.

Preclinical evidence is needed to assess drug-metabolite behaviour in compromised liver function for developing the best antitubercular treatment (ATT) re-introduction regimen in drug-induced liver injury (DILI). The pharmacokinetic behavior of rifampicin (RMP) and its active metabolite des-acetyl-rifampicin (DARP) in DILI's presence is unknown. To study the pharmacokinetic behavior of RMP and DARP in the presence of carbon tetrachloride (CCl4) plus ATT-DILI in rats. Thirty rats used in the experiment were divided equally into six groups. We administered a single 0.5 mL/kg CCl4 intraperitoneal injection in all rats. Groups II, III, IV, and V were started on daily oral RMP alone, RMP plus isoniazid (INH), RMP plus pyrazinamide (PZA), and the three drugs INH, RMP, and PZA together, respectively, for 21-days subsequently. Pharmacokinetic (PK) sampling was performed at 0, 0.5, 1, 3, 6, 12, and 24 h post-dosing on day 20. We monitored LFT at baseline on days-1, 7, and 21 and sacrificed the rats on the last day of the experiment. ATT treatment sustained the CCl4-induced liver injury changes. A significant rise in mean total bilirubin levels was observed in groups administered rifampicin. The triple drug combination group demonstrated 1.43- and 1.84-times higher area-under-the-curve values of RMP (234.56±30.66 vs. 163.55±36.14 µg h/mL) and DARP (16.15±4.50 vs. 8.75±2.79 µg h/mL) compared to RMP alone group. Histological and oxidative stress changes supported underlying liver injury and PK alterations. RMP metabolism inhibition by PZA, more than isoniazid, was well preserved in the presence of underlying liver injury.

Pharmacokinetic Assessment of Pyrazinamide and Pyrazinoic Acid in Carbon tetrachloride-induced Liver Injury Model in Wistar Rats.

We investigated the pharmacokinetic behavior of pyrazinamide (PZA) and pyrazinoic acid (PA) in the presence of carbon-tetrachloride (CCl4) plus antitubercular treatment (ATT) drug-induced liver injury (DILI) in rats. Thirty rats utilized in the experiment were separated equally into five groups. Each rat was injected with 0.5 ml/kg CCl4 intra-peritoneal injection on day zero. Group, I rats did receive only CCl4 (single i.p. injection, 0.5 ml/Kg in olive oil in a 1:1 ratio). Groups II, III, IV, and V did receive daily oral PZA, PZA plus isoniazid (INH), rifampicin (RMP) plus pyrazinamide (PZA), and three drugs together, respectively, for 21-days. Pharmacokinetic sampling was performed at 0, 0.5,1,3,6,12 and 24 hours post-dosing on day-20. Liver function test (LFT) was assessed at days 0,1,7, and 21 days after CCl4 and ATT administration, and rats were sacrificed on the last experiment day. ATT treatment maintained the liver function changes initiated by CCl4 administration. An evidential LFT rise was observed in groups administered with pyrazinamide. Co-administration of Isoniazid caused a 2.02 and 1.78 times increase in Area-under-the-curve (AUC) values of PZA and PA, respectively (p < 0.05). Histological and oxidative-stress changes supported the biochemical and pharmacokinetic observations. The enzyme inhibitory capacity of isoniazid is well-preservd in CCl4-induced liver injury.

Impact of dissolved rare gases (Ar, Xe and He) on single-bubble sonochemistry in the presence of carbon tetrachloride

Impact of dissolved rare gases (Ar, Xe and He) on single-bubble sonochemistry in the presence of carbon tetrachloride

Amidation of Diamantane with Carboxylic Acid Amides and Carbon Tetrachloride in the Presence of Binder-Free Ni-HY Zeolite

N-(Diamantan-1- and 4-yl) carboxamides were synthesized by reaction of diamantane with carboxylic acid amides in the presence of carbon tetrachloride and binder-free Ni-HY zeolite. Optimal amounts of the reactants and catalyst and reaction conditions were found to obtain the target products in high yields.

Leaching of Organic Toxic Compounds from PVC Water Pipes in Medina Al-Munawarah, Kingdom of Saudi Arabia

It is well established that the use of synthetic material in water pipes significantly affects the quality of domestic water, especially trace organics that are leached through with the flow of water. In the present study, the migration of volatile organic compounds (VOCs) from water pipes manufactured of polyvinyl chloride (PVC) has been investigated using static laboratory conditions and in residential areas. The contact of deionized water with various PVC pipes for three successive test periods of 24, 48, and 72 h duration has been made. Twenty water samples were collected from houses within Medina Al-Munawarah residential area and were analyzed by using solid phase extraction, followed by high resolution gas chromatography with flame ionized detector (GC-FID). The presence of carbon tetrachloride (CTC), toluene, chloroform, styrene, o-xylene, bromoform (BF), dibromomethane (DBM), cis-1,3-dichloropropane (Cis-1,3-DCP), and trans-1,3-dichloropropane (Trans-1,3-DCP) was initially confirmed. The most frequent contaminants found were DBM, CTC, and toluene that were monitored in 55%, 50%, and 45% of samples, respectively. The levels of CTC, Cis-1,3-DCP, and Trans-1,3-DCP were found to exceed the World Health Organization (WHO) limits in 50%, 20%, and 20% of samples, respectively. The migration test indicated that nine of the targeted contaminants occur in a double distilled water sample incubated in pipe in laboratory level experiment. This implies that these components are more likely to migrate from PVC pipe in home plumbing systems network.

Analysis of Endocrine-Disrupting Compounds from Cheese Samples Using Pressurized Liquid Extraction Combined with Dispersive Liquid–Liquid Microextraction Followed by High-Performance Liquid Chromatography

Simultaneous extraction and preconcentration of five endocrine disrupting compounds including di-butyl phthalate, di-iso-nonyl phthalates, di-ethylhexyl phthalate, di-ethylhexyl adipate, and bisphenol A from cheese have been developed using pressurized liquid extraction combined with dispersive liquid–liquid extraction followed by high-performance liquid chromatography-diode array detector. In this method, initially, the analytes are extracted into a water-miscible extraction solvent (acetone) at high pressure (1000 psi) and temperature (70 °C) in the presence of carbon tetrachloride as a modifier. After extraction, a volume of the organic phase is removed and dispersed into deionized water. The cloudy solution was centrifuged, and the sedimented phase is used in analysis. Efficient parameters were optimized using one-parameter-at-one-time strategy, and low limits of detection and quantification in the ranges of 0.82–3.1 and 2.8–10 ng g−1 were obtained, respectively. Relative standard deviations lower than 8% show an acceptable precision for the present method. The enrichment factors and extraction recoveries in the ranges of 259–319 and 78–96% were achieved, respectively. Lastly, some real samples were analyzed and di-butyl phthalate and di-ethylhexyl phthalate were found in them.

Reductive dechlorination of carbon tetrachloride by bioreduction of nontronite

Reductive dechlorination of carbon tetrachloride (CT) was investigated during bioreduction of iron-containing clay mineral (i.e., nontronite) by iron-reducing bacteria (Shewanella putrefaciens CN32 (CN32)). In the absence of CT, the production of Fe(II) significantly increased in nontronite suspension with CN32 in 124 d (11.1% of Fe(III) reduction), resulting in formation of new secondary Fe(II) mineral phase (i.e., vivianite (FeII3(PO4)2·8H2O)). In the presence of CT, an acceleration of CT dechlorination was observed after 13 d and it reached almost 68% of removal efficiency at 32 d in nontronite suspension with CN32, which was 1.8 times higher than that by CN32 alone (37%). Significant amounts of formate (30.1%) and CO (2.4%) were measured during the CT dechlorination in the nontronite suspension with CN32. Results obtained from Fe(II) measurement and X-ray diffraction (XRD) showed the acceleration of Fe(II) production after 13 d and the formation of vivianite in the range of 13–25 d, suggesting that the biogenic vivianite enhanced the CT dechlorination in this study. Experimental results from batch kinetic tests, Fe(II) measurements, XRD analysis, and by-product study suggested that the formation of vivianite can play a crucial role for the enhanced reductive dechlorination of CT in phosphorous enriched subsurface environments with iron-containing clay minerals.

Influence of carbon doping and hydrogen co-doping on acceptor related optical transitions in ZnO nanowires

ZnO nanowires grown by metalorganic vapor phase epitaxy in the presence of carbon tetrachloride and hydrogen show two distinct low temperature photoluminescence (PL) bands at 3.237 and 3.309 eV. The band at 3.237 eV is most pronounced in samples grown in the presence of carbon tetrachloride, and is shown to be due to donor–acceptor pair (DAP) emission, based on intensity-dependent and time-resolved PL measurements. An acceptor binding energy of 181 ± 5 meV was inferred from these measurements. We attribute the acceptor in this DAP to the incorporation of nitrogen due to interaction between the carbon and nitrogen precursors. The addition of hydrogen in the presence of CCl4 results in a large enhancement of the carbon related shallow donor bound exciton PL, and the appearance of a strong band at 3.309 eV (e–A0) which is consistent with a free-to-bound transition, most likely (e–A0) as argued by previous works. The (e–A0) designation is based on detailed lineshape analysis as a function of temperature, together with time-resolved PL measurements. Based on this model, an acceptor binding energy for the 3.309 eV band of 133 ± 5 meV was determined, confirming and supporting previous reports.

The effect of solvents on formaldehyde adsorption performance on pristine and Pd doped on single-walled carbon nanotube using density functional theory

The electronic and structural properties of Pd doped single-walled carbon nanotubes show advantages as new nanocomposites that enable a wide variety of applications as nanosensors, nano storage devices, nanoplatform in biosensors. Our previous research demonstrated that Pd atom loaded onto single-walled carbon nanotubes have been shown that sensitivity of Pd/CNT toward CH2O in gas phase is twelve times opposed to intrinsic CNT. A detail and widespread study of solvent effects on adsorption of formaldehyde onto pristine single-walled carbon nanotube and Pd loaded on carbon nanotube was performed under density functional theory framework. Based on the results, carbon nanotube showed no obvious sensitivity toward formaldehyde in considered solvents including water, methanol, ethanol, acetone and carbon tetrachloride. Electronic properties of Pd/CNT after CH2O adsorption were considerably changed. Also, the most and the least adsorption energy were reported in the presence of carbon tetrachloride and methanol from O (O-Pd/CNT) and para (para-Pd/CNT) orientations with −1.174eV and −0.519eV adsorption energy respectively. NBO analyses showed in the similar transfers, there was the most strong charge transfer from formaldehyde (O orientation) to Pd/CNT in carbon tetrachloride solution through lone pair of O atom toward lone pair* of Pd site with second-order perturbation energy (E(2)) equal 113.345kJ/mol. These results are representative of strong chemisorption between CH2O and Pd/CNT in the presence of carbon tetrachloride. Quantum theory of atom in molecule (QTAIM) calculations indicate that the most accumulated electron charge density was between Pd-O in the O-Pd/CNT in carbon tetrachloride organic solution.

Synthesis, structure and adsorption properties of nonstoichiometric carbon nitride in comparison with nitrogen-containing carbons

The samples of nonstoichiometric carbon nitride characterized by spatial ordering, large pore volume (up to 0.8cm3/g) and specific surface area (up to 585m2/g) were obtained via matrix carbonization of ethylenediamine in the presence of carbon tetrachloride in mesoporous molecular sieves KIT-6 and MCF as exotemplates. In contrast to nitrogen-containing carbons (obtained by modification of carbon samples with nitrogen in the result of compatible thermal treatment of the initial porous carbon with melamine) nonstoichiometric carbon nitride contains much more nitrogen (up to 13.7wt.% (C/N=6), compared with preceding 0.6wt.%) and increased the quantity of basic nitrogen-containing groups (in particular, amino groups)—up to 0.68mmol/g (vs. 0.46mmol/g). The increase of adsorption capacity towards hydrogen and carbon dioxide: adsorption potential, differential heat of CO2 adsorption, specific adsorption on the pore surface—from 5.4 to 7.3μmol H2/m2 and from 2.2 to 5.4μmol CO2/m2 for carbon and synthesized samples of nonstoichiometric carbon nitride, respectively, due to the incorporation of nitrogen atoms into the carbon framework was noticed.

ChemInform Abstract: Atherton‐Todd Reaction: Mechanism, Scope and Applications

AbstractReview: 146 refs.

A new approach towards synthesis of phosphorylated alkenes

New method of synthesis of trans-vinylphosphonates via reaction of trimethylsilyl(methyl)phosphonites with carbonyl compounds in the presence of carbon tetrachloride has been developed. The reaction involves formation of C-trimethylsilyl substituted ylides and 2-chloro-1,2λ5-oxaphosphetanes as intermediates.

Atherton-Todd reaction: mechanism, scope and applications.

Initially, the Atherton–Todd (AT) reaction was applied for the synthesis of phosphoramidates by reacting dialkyl phosphite with a primary amine in the presence of carbon tetrachloride. These reaction conditions were subsequently modified with the aim to optimize them and the reaction was extended to different nucleophiles. The mechanism of this reaction led to controversial reports over the past years and is adequately discussed. We also present the scope of the AT reaction. Finally, we investigate the AT reaction by means of exemplary applications, which mainly concern three topics. First, we discuss the activation of a phenol group as a phosphate which allows for subsequent transformations such as cross coupling and reduction. Next, we examine the AT reaction applied to produce fire retardant compounds. In the last section, we investigate the use of the AT reaction for the production of compounds employed for biological applications. The selected examples to illustrate the applications of the Atherton–Todd reaction mainly cover the past 15 years.

ChemInform Abstract: Hydration of Alkenes and Cycloalkenes in the Presence of Chromium and Copper Complexes.

Chromium and copper complexes catalyzed hydration of acyclic and cyclic olefins in the presence of carbon tetrachloride at 110–160°C (4–12 h) with formation of the corresponding alcohols.

Hydration of alkenes and cycloalkenes in the presence of chromium and copper complexes

Chromium and copper complexes catalyzed hydration of acyclic and cyclic olefins in the presence of carbon tetrachloride at 110–160°C (4–12 h) with formation of the corresponding alcohols.

Chemical Fixation of Carbon Dioxide Catalyzed by Bimetallic Aluminum(Salen) Complex

Bimetallic aluminum(salen) complexes were prepared and used as catalyst for the synthesis of DPC from CO2 and phenol in the presence of carbon tetrachloride. The bimetallic complex derived from 3,5-ditert salicylaldehyde and 1,2-cyclohexanediamine revealed more excellent activity than that obtained in the presence of other complexes and the simple Lewis acid ZnCl2. The influence of the amount of complex and the reaction conditions including the pressure of CO2 and the reaction temperature was also investigated.

Ethylene oligomerization on the chromium ethylhexanoate-triethylaluminum-2,5-dimethylpyrrol catalytic system in the presence of carbon tetrachloride

The kinetics of the selective ethylene oligomerization reaction on the chromium(III) ethylhex� anoate-Al(C2H5)3-2,5�dimethylpyrrol homogeneous catalytic system in the presence of CCl 4 has been studied. The reaction rate order in ethylene, the activation energy, and the selectivity of reaction for 1�hexene have been determined.

In Situ Synthesis of Chlorinated Fullerenes by the High‐Frequency Furnace Method

AbstractExohedrally chlorinated fullerenes have been synthesized by in situ chlorination using the high‐frequency furnace method in the presence of carbon tetrachloride as reagent. In addition to the previously reported chlorinated non‐IPR (isolated pentagon rule) fullerene cages of C2nCl2m (n = 25, 27, 28, 30, 32 and 33, m = 2–6), a C68 and various new higher fullerenes including C2nCl2m with n = 36, 37 and 39 were present in the soot extracts in significant quantities, as shown by HPLC/off‐line mass spectrometric analyses. A more detailed analysis showed the presence of several species with the same carbon content that could arise from either the formation of different isomers or different degrees of chlorination.

Kinetic study of RuIII -catalyzed polymerization of methylmethacrylate initiated with n -butylamine in the presence of carbon tetrachloride by a charge-transfer mechanism

Ruthenium trichloride (RuCl3 or RuIII) catalyzed polymerization of methylmethacrylate (MMA) initiated with n-butylamine (BA) in the presence of carbon tetrachloride (CCl4) by a charge-transfer mechanism has been investigated in a dimethylsulfoxide (DMSO) medium by employing a dilatometric technique at 60°C. The rate of polymerization (Rp) has been obtained under the conditions [CCl4]/[BA] ⩽ 1 and [CCl4]/[BA] ⩾ 1. The kinetic data indicate the possible participation of the charge-transfer complex formed between the amine–RuIII complex and CCl4 in the polymerization of MMA. In the absence of either CCl4 or BA, no polymerization of MMA is observed under the present experimental conditions. The rate of polymerization is inhibited by hydroquinone, suggesting a free-radical initiation. © 2010 Wiley Periodicals, Inc. Int J Chem Kinet 43: 70–77, 2011