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.
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.
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.
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.