Search results for "Oxidation."

The Radical Trap in Atom Transfer Radical Polymerization Need Not Be Thermodynamically Stable. A Study of the MoX3(PMe3)3 Catalysts

2005

The molybdenum(III) coordination complexes MoX(3)(PMe(3))(3) (X = Cl, Br, and I) are capable of controlling styrene polymerization under typical atom transfer radical polymerization (ATRP) conditions, in conjunction with 2-bromoethylbenzene (BEB) as an initiator. The process is accelerated by the presence of Al(OPr(i))(3) as a cocatalyst. Electrochemical and synthetic studies aimed at identifying the nature of the spin trap have been carried out. The cyclic voltammogram of MoX(3)(PMe(3))(3) (X = Cl, Br, I) shows partial reversibility (increasing in the order ClBrI) for the one-electron oxidation wave. Addition of X(-) changes the voltammogram, indicating the formation of MoX(4)(PMe(3))(3) f…

Electrochemical Treatment of Synthetic Wastewaters Contaminated by Organic Pollutants at Ti 4 O 7 Anode. Study of the Role of Operative Parameters by…

2022

In the last years, an increasing attention has been devoted to the utilization of anodic oxidation (AO) technologies for the treatment of wastewater polluted by recalcitrant organics. Recently, Ti4O7 was proposed as a promising anode for AO for the treatment of various organics. Here the potential utilization of commercial Ti4O7 anodes has been evaluated considering the electrochemical treatment of synthetic wastewater contaminated by three very different organic molecules (namely, oxalic acid, phenol and Acid Orange 7), all characterized by a very high resistance to AO. The performances of Ti4O7 were compared with that of two largely investigated anodes: Boron-doped diamond (BDD), which is…

Electrochemical synthesis of coenzymes Qn by oxidation of tetramethoxy precursors

2009

The electrochemical oxidation of tetramethoxy precursors (2) to coenzymes Q (n) (1) at a carbon anode was investigated both in a bench-scale batch electrochemical reactor and in a continuous recirculation reaction system equipped with a parallel-plate electrochemical divided cell. High faradic efficiency (> 60%) and excellent selectivity (> 90%) in coenzymes Q (n) were obtained in CH3CN or CH3CN/CH2Cl2 + 0.15 M Bu4NBF4 under potentiostatic or amperostatic alimentation.

Electronic Interactions in a New π-Extended Tetrathiafulvalene Dimer

2006

The first pi-extended tetrathiafulvalene (exTTF) dimer in which the two exTTF units are covalently connected by 1,3-dithiole rings has been obtained in a multistep synthetic procedure involving the Ullmann cross-coupling reaction by using copper(I) thiophene-2-carboxylate (CuTC). The electronic spectrum reveals a significant electronic interaction between the exTTF units. The electrochemical study carried out by cyclic voltammetry in solution and in thin-layer conditions, and the electrochemical simulation and spectroelectrochemical (SEC) measurements confirm the electronic communication and show that the oxidation of dimer 14 occurs as two consecutive 2 e(-) processes D(0)-D(0)-->D(2+)-D(0…

Photo-oxidation Behaviour of EVA Antimicrobial Films

2010

Determination of antimony in drinking waters by an inexpensive, reproducible hydride generator for atomic spectroscopy.

1991

A method for determining antimony in drinking waters is described. In order to prevent a substantial error caused by the different oxidation states of antimony, Sb(V) is reduced to Sb(III) with potassium iodide-ascorbic acid. Covalent hydride is generated with a home made device by adding NaBH4. The hydride is then atomized in a flame-heated silica tube and atomic absorption is measured spectrophotometrically. The optimal conditions for this determination are discussed and interference effects are described. Results obtained by determining linearity range (0-200 ng), detection (LOD) and quantitation (LOQ) limits (LOD = 0.347 ng/ml, LOQ = 1.158 ng/ml), precision (instrumental CV 4.08% and me…

Increase in stability and change in supramolecular structure of β-carotene through encapsulation into polylactic acid nanoparticles

2011

International audience; β-Carotene (BC) exhibits controversial antioxidant properties as it may act also as a prooxidant. Its stability toward oxidation depends on its dispersion form and can be increased through encapsulation. In this study, oxidation of BC from synthetic and natural origins was investigated after dispersion in Tween micelles or poly lactic acid (PLA) particles. Two oxidation systems were used: autooxidation and oxidation by xanthine oxidase-generated-reactive oxygen species. Results showed that synthetic BC formed nanometric negatively-charged particles in both Tween micelle and PLA systems, whereas the natural BC sample used was shown to be already pre-oxidised, forming …

The Effect of Methanolic Leaf Extract of Boerhavia diffusa Linn. (Nictaginaceae) on the Activities of Antidiabetic, Anti-inflammatory and Antioxidant…

2018

Diabetic therapeutic potentiality of methanol extract of stem leaves of Boerhavia diffusa was investigated following in-vivo study models in streptozotocin-induced diabetic rat. Methanol extract of stem leaves of Boerhavia diffusa exerted the glucose lowering effect an increase in serum insulin level on 28st day of postadministration. In addition to a higher expression of insulin receptor A. The extract treatment or glibenclamide for 28 days significantly (p<0.05) reduced HbA1c. Boerhavia diffusa L. or glibenclamide for 28 days show no damaging effect on red blood count and hemoglobin when compared to the control group.  Significant (p<0.05) increase in platelet count and white blood cell c…

Oxidative stress of alternariol in Caco-2 cells

2014

Alternariol (AOH) is a mycotoxin produced by fungus Alternaria. It is found in a wide variety of fruits and cereals products. AOH is able to damage human health. The aim of this study was to evaluate the cytotoxicity of AOH in human colon adenocarcinoma (Caco-2) cells. Moreover, some events related to oxidative stress were evaluated: reactive oxygen species (ROS) generated by oxidation of 2',7'-dichlorodihydrofluorescein diacetate; peroxidation of lipid (LPO) by malondialdehyde (MDA) production; and antioxidant enzymatic capability of catalase (CAT) and superoxide dismutase (SOD). Cytotoxicity of AOH (from 3.125 to 100 μM) was determined during 24, 48 and 72 h of exposure by different endpo…

Oxidative stability of virgin olive oils

2001

An investigation was carried out on virgin olive oils of the Gentile (Larino), Gentile (Colletorto), Coratina, and Leccino varieties, harvested at different times, to assess their oxidation stability. The olive oils were analyzed by means of peroxide, K-232, and K 270 values at 1, 6, 12, and 18 mon of storage in green bottles, in the dark, at temperatures ranging from a mean of 6degreesC in winter to 12degreesC in summer. A subsample was also oven-tested at 75degreesC and then analyzed on a weekly basis using the same oxidative parameters. The less ripe the olives (harvested in the same area, during 1 mon), the more resistant the olive oils were to forced oxidation. The amount of total phen…