C:Corrosive;
79-43-6Relevant articles and documents
Photocatalytic degradation of dichloroacetyl chloride adsorbed on TiO 2
Nishikiori, Hiromasa,Tagahara, Makoto,Mukoyama, Leo,Fujii, Tsuneo
, p. 947 - 957 (2010)
Dichloroacetyl chloride (DCAC) attracted our attention as an intermediate product of the photocatalytic degradation of trichloroethylene (TCE). The adsorption and photocatalytic reaction of DCAC on TiO2 have been investigated by FTIR spectroscopy. The influence of the surface structure of several TiO2s on the reaction mechanism was discussed in order to understand the complete degradation mechanism of TCE as well as DCAC. DCAC was transformed into dichloroacetic acid (DCAA) on the relatively hydrophobic TiO2 surface by the small amount of the water molecules weakly adsorbed on the surface. This DCAA was degraded to phosgene, CO2, and CO during UV irradiation. For the hydrophilic TiO2, DCAC was mainly transformed into the dichloroacetate anion. UV irradiation allowed this species to produce chloroform in addition to phosgene, CO2, and CO. It is suggested that DCAC easily reacts with the Ti-OH group on the hydrophilic TiO2 and forms the bidentate titanium chelate of dichloroacetate, which efficiently degrades into chloroform.
Role of humic acids in the TiO2-photocatalyzed degradation of tetrachloroethene in water
Selli, Elena,Baglio, Daniela,Montanarella, Luca,Bidoglio, Giovanni
, p. 1827 - 1836 (1999)
The effect of humic acids on the TiO2-mediated photocatalytic degradation of tetrachloroethene (PCE) was kinetically investigated at different pH and initial substrate concentrations. The process occurs through two parallel paths: a major oxidative route leading to mineralization and a reductive route leading to the formation of dichloroacetic acid (DCAA), also undergoing photodegradation. The rate of PCE decomposition was found to decrease in the presence of humic acids adsorbed on the semiconductor surface, while the concentration of the intermediate dichloroacetic acid increased. This is a consequence of the scavenging action of humic acids toward photoproduced surface oxidant species, which makes conduction band electrons more easily available for interface reactions. Kinetic studies on the effect of humic acids in the TiO2-mediated photodegradation of dichloroacetic acid showed that the progressively greater accumulation of this highly toxic intermediate, observed with increasing humic acids content, was a consequence of both an increase in the rare of its production from PCE and a decrease in the rate of its oxidative photodegradation. The effect of humic acids on the TiO2-mediated photocatalytic degradation of tetrachloroethene (PCE) was kinetically investigated at different pH and initial substrate concentrations. The process occurs through two parallel paths: a major oxidative route leading to mineralization and a reductive route leading to the formation of dichloroacetic acid (DCAA), also undergoing photodegradation. The rate of PCE decomposition was found to decrease in the presence of humic acids adsorbed on the semiconductor surface, while the concentration of the intermediate dichloroacetic acid increased. This is a consequence of the scavenging action of humic acids toward photoproduced surface oxidant species, which makes conduction band electrons more easily available for interface reactions. Kinetic studies on the effect of humic acids in the TiO2-mediated photodegradation of dichloroacetic acid showed that the progressively greater accumulation of this highly toxic intermediate, observed with increasing humic acids content, was a consequence of both an increase in the rate of its production from PCE and a decrease in the rate of its oxidative photodegradation.
Correlation of molecular and morphologic effects of thermoembolization in a swine model using mass spectrometry imaging
Guo, Chunxiao,Baluya, Dodge L.,Thompson, Emily A.,Whitley, Elizabeth M.,Cressman, Erik N.K.
, (2020)
Hepatocellular carcinoma is a growing worldwide problem with a high mortality rate. This malignancy does not respond well to chemotherapy, and most patients present late in their disease at which time surgery is no longer an option. Over the past three decades, minimally invasive methods have evolved to treat unresectable disease and prolong survival. Intra-arterial embolization techniques are used for large or multiple tumors but have distressingly high levels of local recurrence and can be costly to implement. A new method called thermoembolization was recently reported, which destroys target tissue by combining reactive exothermic chemistry with an extreme local change in pH and ischemia. Described herein are experiments performed using this technique in vivo in a swine model. A microcatheter was advanced under fluoroscopic guidance into a branch of the hepatic artery to deliver a targeted dose of dichloroacetyl chloride dissolved in ethiodized oil into the liver. The following day, the animals were imaged by computed tomography and euthanized. Assessing the reaction product distribution and establishing a correlation with the effects are important for understanding the effects. This presented a significant challenge, however, as the reagent used does not contain a chromophore and is not otherwise readily detectable. Mass spectrometry imaging was employed to determine spatial distribution in treated samples. Additional insights on the biology were obtained by correlating the results with histology, immunohistochemistry, and immunofluorescence. The results are encouraging and may lead to a therapy with less local recurrence and improved overall survival for patients with this disease.
Ionic liquid-hemoglobin-carbon paste composite bioelectrode and its electrocatalytic activity
Xuan, Zong-Wei,Sun, Xiao-Ying,Jiao, Guo-Song,Zhai, Zi-Qin,Sun, Wei,Lu, Lu-De
, p. 1262 - 1267 (2010)
Anew carbon ionic liquid paste bioelectrode was fabricated by mixing hemoglobin (Hb) with graphite powder, ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF4) and liquid paraffin homogeneously. Nafion film was cast on the electrode surface to improve the stability of bioelectrode. Direct electrochemistry of Hb in the bioelectrode was carefully investigated. Cyclic voltammetric results indicated that a pair of well-defined and quasi-reversible electrochemical responses appeared in pH 7.0 phosphate buffer solution (PBS), indicating that direct electron transfer of Hb was realized in themodified electrode. The formal potential (E0') was calculated as -0.316 V (vs. SCE), which was the typical characteristic of the electrochemical reaction of heme Fe(III)/Fe(II) redox couple. Based on the cyclic voltammetric results the electrochemical parameters of the electrode reaction were calculated. This bioelectrode showed high electrocatalytic activity towards the reduction of trichloroacetic acid (TCA) with good stability and reproducibility.
TiO2 MEDIATED PHOTOOXIDATION OF TRICHLOROETHYLENE AND TOLUENE DISSOLVED IN FLUOROCARBON SOLVENTS
Sun, Yunfu,Brown, Gilbert M.,Moyer, Bruce A.
, p. 3575 - 3584 (1995)
Titanium dioxide mediated photodegradation of trichloroethylene (TCE) and toluene dissolved in a fluorocarbon solvent (Galden HT110) was demonstrated. The photodegradation of TCE yielded dichloroacetic acid as a major intermediate. The TCE reaction kinetics and high photoefficiency suggest autocatalysis and/or a radical chain reaction mechanism. Photooxidation of toluene is a first-order reaction. Membrane-assisted solvent extraction of TCE from water to the fluorocarbon solvent was demonstrated, and the combination of photooxidation and extraction from the basis for a novel two-stage process for the removal and destruction of organic contaminants from water.
Photocatalytic degradation of gaseous trichloroethylene on porous titanium dioxide pellets modified with copper(II) under visible light irradiation
Tashiro, Keigo,Tanimura, Toshifumi,Yamazaki, Suzuko
, p. 228 - 235 (2019/04/17)
Porous titanium dioxide pellets modified with copper(II) ion (Cu-TiO2) were synthesized by sol-gel method with dialysis for photocatalytic degradation of gaseous trichloroethylene (TCE) under visible light (VL) irradiation. TCE was completely degraded by passing the gas stream (mole fractions of oxygen and TCE were 0.2 and 1.75 × 10?4, respectively) at the flow rate of 25 mL min?1 through 0.2 g of the Cu-TiO2 pellets (Cu content: 0.1 atom%) calcined at 200 °C. TCE was converted mainly to carbon dioxide, dichloroacetic acid (DCAA), and inorganic chlorine species. Relatively small quantities of pentachloroethane (PCA) and trichloroacetaldehyde (TCAH) were detected as products on the Cu-TiO2 surface. Comparison with porous TiO2 pellets under ultraviolet irradiation revealed that more chlorinated products and less carbon dioxide were formed on Cu-TiO2 under VL irradiation. The mineralization of TCE to carbon dioxide was calculated to be only ca. 30.0%. It is noted that DCAA, PCA and TCAH were accumulated on the surface and were extracted with ethyl acetate. The porous Cu-TiO2 pellets show promise as the photocatalyst acting under VL irradiation for converting TCE gas to chlorinated compounds which can be used in industries.
A Straightforward Homologation of Carbon Dioxide with Magnesium Carbenoids en Route to α-Halocarboxylic Acids
Monticelli, Serena,Urban, Ernst,Langer, Thierry,Holzer, Wolfgang,Pace, Vittorio
supporting information, p. 1001 - 1006 (2019/01/30)
The homologation of carbon dioxide with stable, (enantiopure) magnesium carbenoids constitutes a valuable method for preparing α-halo acid derivatives. The tactic features a high level of chemocontrol, thus enabling the synthesis of variously functionalized analogues. The flexibility to generate magnesium carbenoids through sulfoxide-, halogen- or proton- Mg exchange accounts for the wide scope of the reaction. (Figure presented.).
Thermodynamically leveraged tandem catalysis for ester RC(O)O-R′ bond hydrogenolysis. scope and mechanism
Lohr, Tracy L.,Li, Zhi,Assary, Rajeev S.,Curtiss, Larry A.,Marks, Tobin J.
, p. 3675 - 3679 (2015/06/16)
Rapid and selective formal hydrogenolysis of aliphatic ester RC(O)O-R′ linkages is achieved by a tandem homogeneous metal triflate + supported palladium catalytic system. The triflate catalyzes the mildly exothermic, turnover-limiting O-R′ cleavage process, whereas the exothermic hydrogenation of the intermediate alkene further drives the overall reaction to completion.
Effect of dissolved oxygen concentration on iron efficiency: Removal of three chloroacetic acids
Tang, Shun,Wang, Xiao-mao,Mao, Yu-qin,Zhao, Yu,Yang, Hong-wei,Xie, Yuefeng F.
, p. 342 - 352 (2015/03/04)
The monochloroacetic, dichloroacetic and trichloroacetic acid (MCAA, DCAA and TCAA) removed by metallic iron under controlled dissolved oxygen conditions (0, 0.75, 1.52, 2.59, 3.47 or 7.09mg/L DO) was investigated in well-mixed batch systems. The removal of CAAs increased first and then decreased with increasing DO concentration. Compared with anoxic condition, the reduction of MCAA and DCAA was substantially enhanced in the presence of O2, while TCAA reduction was significantly inhibited above 2.59mg/L. The 1.52mg/L DO was optimum for the formation of final product, acetic acid. Chlorine mass balances were 69-102%, and carbon mass balances were 92-105%. With sufficient mass transfer from bulk to the particle surface, the degradation of CAAs was limited by their reduction or migration rate within iron particles, which were dependent on the change of reducing agents and corrosion coatings. Under anoxic conditions, the reduction of CAAs was mainly inhibited by the available reducing agents in the conductive layer. Under low oxic conditions, the increasing reducing agents and thin lepidocrocite layer were favorable for CAA dechlorination. Under high oxic conditions, the redundant oxygen competing for reducing agents and significant lepidocrocite growth became the major restricting factors. Various CAA removal mechanisms could be potentially applied to explaining the effect of DO concentration on iron efficiency for contaminant reduction in water and wastewater treatment.
The electrochemical studies of cytochrome c incorporated in 3D porous calcium alginate films on glassy carbon electrodes
Jian, Shan,Liu, Xingchao,Sun, Hong,Hou, Shifeng
, p. 6165 - 6172 (2014/01/23)
In this work, the cytochrome c (Cyt c) was incorporated in three-dimension (3D) porous calcium alginate (CA) films prepared by using sodium alginate, calcium chloride and polyethylene glycol, and formed the electroactive porous Cyt c-CA composite films. The stable composite films were characterized by means of scanning electron microscopy (SEM), UV-vis absorption, cyclic voltammetry (CV) and square-wave voltammetry (SWV) techniques. UV-vis experiments demonstrated that Cyt c assembled in the 3D porous CA films retains its near native conformation at medium pH. The Cyt c-CA films modified on glassy carbon electrodes showed a pair of well-defined and nearly reversible cyclic voltammetry peaks at about -0.352 V vs. SCE in protein-free buffer, which originated from heme FeIII/II redox couples within Cyt c. The electrochemical parameters such as apparent heterogeneous electron transfer rate constant (ks) and formal potential (Eo') were estimated by fitting the data of SWV with nonlinear regression analysis. The Cyt c-CA films showed the electrocatalytic activity toward dioxygen, hydrogen peroxide, nitrite and trichloroacetic acid with significant decreases in the electrode potential required. Experimental data demonstrated that the porous film can provide a favorable microenvironment for the protein to directly transfer electrons with the underlying electrode and possess good stability and reproducibility, showing the possible future application of the films for biosensors and biocatalysis.
