Showing papers on "Potassium dichromate published in 2003"
TL;DR: The results show that the leaf extract of Seabuckthorn protected the animals from the chromium induced oxidative injury significantly and enhanced glutamate oxaloacetate transferase and glutamate pyruvateTransferase levels in the serum.
147 citations
TL;DR: In this paper, the influence of sealing methods on the corrosion behavior of three anodized aluminum alloys, 1070, 2024 and 7075, in NaCl solutions was studied, and the anodic films were sealed by the methods of boiling water, stearic acid, potassium dichromate and nickel fluoride, respectively.
Abstract: The influences of sealing methods on the corrosion behavior of three anodized aluminum alloys, 1070, 2024 and 7075, in NaCl solutions were studied. The anodic films were sealed by the methods of boiling water, stearic acid, potassium dichromate and nickel fluoride, respectively. Passivation and pitting behaviors resulting from the sealing treatments were studied using the potentiodynamic polarization, and surface morphology was examined by scanning electron microscopy. The results show that boiling water and potassium dichromate sealed films provide relatively higher corrosion resistance in acidic solution, while nickel fluoride sealed film is better in basic solution. Stearic acid sealed film provides good corrosion resistance both in acidic and in basic solutions. The influencing mechanisms of different sealing methods on corrosion resistance of the anodized alloys were discussed.
145 citations
TL;DR: In this article, experiments have been conducted on Cr(VI) contaminated kaolin to determine the kinetics of electroremediation and the associated rate controlling mechanism, showing that approximately 15% chromium was removed in the first 20 hours and thereafter, there was a drastic reduction in the chromium removal rate.
28 citations
TL;DR: Only sodium selenate has shown antigenotoxic properties against potassium dichromate in the Ames test and in human lymphocytes in the Comet assay, and only Sodium selenite did not decrease the genotoxicity of potassium dichrome or hydrogen peroxide when administered as a pre-treatment or at the same time, or when potassium dichromaate and sodium seenite treatments were for different time periods.
Abstract: Selenium is an environmental metal that occurs ubiquitously and is produced throughout the world for various industrial activities. Selenium has been reported to have anticarcinogenic and preventive effects in clinical and epidemiological studies. Selenium supplements can inhibit chemically-induced tumours. From the viewpoint of genotoxicity, selenium has not been adequately studied and an IARC review concluded that there were not sufficient data to consider it a carcinogen for man. In contrast, hexavalent chromium is classified as a known respiratory carcinogen producing DNA damage through free oxygen radicals. In the present study, a collaborative study has been carried out to evaluate the genotoxicity of selenium compounds and their possible interactions with potassium dichromate and hydrogen peroxide. Thus, in laboratory 1 (U.K.), the genotoxic effects of three selenium compounds were examined. Sodium selenate, sodium selenite, and selenous acid were investigated in the Ames test using strain TA102 and in the Comet assay using human lymphocytes, and also investigated for their interaction with potassium dichromate. In the Ames test, it was shown that potassium dichromate produced a highly mutagenic response, whilst the three selenium compounds did not. In combination, sodium selenate reduced the genotoxicity of potassium dichromate, but sodium selenite and selenous acid had no effect. In the Comet assay, potassium dichromate induced DNA damage, but so did the selenium compounds. In combination with potassium dichromate, however, only sodium selenate reduced its effect, whereas sodium selenite and selenous acid exacerbated DNA damage. In laboratory 2 (Spain), in the TK6 lymphoblastoid cell line, the Comet assay showed that sodium selenite was non-genotoxic, while potassium dichromate and hydrogen peroxide induced DNA damage. It was also shown that sodium selenite did not decrease the genotoxicity of potassium dichromate or hydrogen peroxide when administered as a pre-treatment or at the same time, or when potassium dichromate and sodium selenite treatments were for different time periods. Thus, only sodium selenate has shown antigenotoxic properties against potassium dichromate in the Ames test and in human lymphocytes in the Comet assay.
25 citations
01 Jan 2003
TL;DR: Grafting of various monomers onto macromolecules such as starch, cellulose, etc. has opened a vast horizon to the scientists to amend some attentive properties of such huge homopolymers as mentioned in this paper.
Abstract: Grafting of various monomers onto macromolecules such as starch, cellulose, etc. has opened a vast horizon to the scientists to amend some attentive properties of such huge homopolymers. For instance, we may use modified starch in health materials [1,2], cation exchanger membrane [3], and corrosion protection of aluminium [4]. Grafting of acrylic acid onto starch has been reported by potassium bromate/thiocarbonate [5] and permanganate/acid [6]. On other hand, grafting of acrylamide onto Kinetics and Mechanism of Graft Copolymerization of Vinyl Monomers (Acrylamide, Acrylic Acid, and Methacrylate) onto Starch by Potassium Dichromate as Redox Initiator
19 citations
TL;DR: The effects of hexavalent chromium in the haemolymph cells of Procambarus clarkii are investigated using the micronuclei (MN) test using the objective of developing a field-assay for the detection of genotoxic pollutants in water.
18 citations
Patent•
14 May 2003
TL;DR: In this paper, a chemical rust-preventing liquid for processing rust on metal surface is described. But it is a water solution with phosphoric acid as main component and the raw material consists of water 200-300 pts.
Abstract: The present invention relates to a chemical rust-preventing liquid for processing rust on metal surface. It is a water solution with phosphoric acid as main component and the raw material consists ofwater 200-300 pts.wt, phosphoric acid 80-160 pts.wt. potassium dichromate 1-5 pts.wt., potassium nitrate 0.5-4 pts.wt., zinc oxide 1-6 pts.wt. trisodium phosphate 1-8 pts.wt., sodium molybdenate 0.01-1 pts.wt. and CMC 1-8 pts.wt. The rust-preventing liquid is applied or sprayed onto the surface of rusted ferrous metal product, so that the oxde layer is converted into phoshpate or chromate, which is attached to the surface of the metal product to form one excellent protecting layer and to reach the rust-eliminating an dpreventing aim.
16 citations
TL;DR: The release of IFN‐γ in the supernatants of the peripheral blood lymphocytes was significantly higher in the patients with proven allergy to chromate, and further studies are needed to determine if IFN-γ release may serve as an additional diagnostic tool in contact dermatitis.
Abstract: The use of in vitro release of interferon-gamma (IFN-gamma) in the diagnosis of contact allergy to potassium dichromate was studied in 20 patients who had positive patch tests to chromate and in 30 control subjects (10 patients with contact dermatitis, allergic to other allergens, 10 patients with other dermatologic diseases and 10 healthy subjects) The release of IFN-gamma in the supernatants of the peripheral blood lymphocytes was significantly higher in the patients with proven allergy to chromate (P = 0001) Further studies are needed to determine if IFN-gamma release may serve as an additional diagnostic tool in contact dermatitis
12 citations
TL;DR: The dichromates and halochromates of heterocyclic bases oxidize diethyl sulfide via a common mechanism and the activation free energies do not differ significantly.
Abstract: The oxidations of diethyl sulfide by potassium dichromate, pyridinium dichromate, quinolinium dichromate, imidazolium dichromate, nicotinium dichromate, isonicotinium dichromate, pyridinium fluorochromate, quinolinium fluorochromate, imidazolium fluorochromate, pyridinium chlorochromate, quinolinium chlorochromate, and pyridinium bromochromate follow identical kinetic orders—first-order each with respect to the chromium(VI) reagents, sulfide and hydrogen ion, and moderately inhibited by manganese(II) ion. The energy of activation varies linearly with the logarithm of frequency factor and so does the enthalpy of activation with the entropy of activation. Also, the activation free energies do not differ significantly. The dichromates and halochromates of heterocyclic bases oxidize diethyl sulfide via a common mechanism. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 35: 1–8, 2003
10 citations
TL;DR: Bueler et al. as discussed by the authors used a modified clay as a phase-transfer catalyst for the selective oxidation of primary alcohols to aldehydes, and showed that the phase transfer catalysis results in nearly complete oxidation of the 2-ethylhexanol in 40 min at room temperature, with high selectivity to the 2ethylhexanal, compared to 48 h in its absence.
7 citations
TL;DR: In this paper, a surface X-ray diffraction study of the {0, 0, 1} faces of potassium dichromate crystals in a humid environment is presented, showing a potassium termination.
TL;DR: In this paper, the influence of antimony in sulfuric acid and sodium sulfate (Na2SO4) solutions has been studied by open-circuit potentiometers.
Abstract: The influence of potassium dichromate (K2Cr2O7) on the corrosion behavior of antimony in sulfuric acid (H2SO4) and sodium sulfate (Na2SO4) solutions has been studied by open-circuit potent...
TL;DR: Evaluating relevance is difficult, and the results of relevance scoring vary widely between different groups, so a consensus on the definition and standardization of the concept of relevance is needed.
Abstract: Our purpose was to determine the proportion of relevant patch test reactions among all patch tested patients in the National Skin Centre (NSC), Singapore, from 1 January 1999 to 31 December 2000. A retrospective study was made of the patch test records of all patients patch tested in the study period. The proportion of relevant patch tests in this population was then determined. The allergens most likely to have present or past relevance were: nickel sulfate (79%), p-phenylenediamine (76%), colophonium (73%), cobalt chloride (68%) and potassium dichromate (67%). The most common allergens for each of the following relevance categories were as follows - present: p-phenylenediamine, thiuram mix, potassium dichromate; past: colophony, nickel sulfate, cobalt chloride; exposed: neomycin, gold sodium thiosulfate, fragrance mix and unknown: gold sodium thiosulfate, potassium dichromate, cobalt chloride. Evaluating relevance is difficult, and the results of relevance scoring vary widely between different groups. A consensus on the definition and standardization of the concept of relevance is needed.
Journal Article•
TL;DR: In this paper, the rate of pyrite oxidation in perchloric acid solutions was investigated at temperatures ranging from 30°C to 40°C, potassium dichromate concentration from 0.001 to 0.05 mol L - 1, particle size fractions from 50 to 150 m m and pH values down to 2.83.
Abstract: The kinetics of pyrite oxidation in perchloric acid solutions were investigated at temperatures ranging from 30°C to 40°C, potassium dichromate concentration from 0.001 to 0.05 mol L - 1, particle size fractions from 50 to 150 m m and pH values down to 2.83. The rate of the oxidation reaction is described by the following expression: r = bkS0.51[K2Cr2O7]0.64[H+ ]0.22 where S is the surface area of reacting solid, r represents the amount of Fe release in solution per unit surface area per unit time, b is a stoichiometric factor, k is the rate constant, and [K2Cr2O7] and [H+ ] are the potassium dichromate and hydrogen ion concentrations respectively. The magnitude of the activation energy (74.83 kJ mol-1) and the direct relationship between the rate constant and initial pyrite specific surface area are in agreement with a mechanism controlled by a chemical reaction. Trace element content had no statistically significant effect on the oxidation rate.
TL;DR: In this paper, the authors describe the selective oxidation of primary alcohols to the corresponding aldehydes by potassium dichromate at room temperature under solvent-free conditions, which can also oxidise secondary alcohols.
Abstract: Selective oxidation of primary alcohols to the corresponding aldehydes by potassium dichromate at room temperature under solvent-free conditions are described. This new procedure can also oxidise secondary alcohols.
Journal Article•
TL;DR: In this article, a low-sulphur expandable graphite was prepared using acetic anhydride as inserting agent and hydrogen peroxide and potassium dichromate as mixed oxidants.
Abstract: Lowsulphur expandable graphite was prepared using acetic anhydride as inserting agent and hydrogen peroxide and potassium dichromate as mixed oxidants.The best process conditions are as follows:m(graphite)∶m(acetic anhydride)∶m(conc.H2SO4)∶m(H2O2)∶m(K2Cr2O7)=1∶14∶05∶012∶012,reaction time 1 h and reaction temperature 45 ℃.The expanded volume of graphite is 280 mL/g and the sulphur content w(S) is 011%.
TL;DR: Using 2-(8-quinolylazo)-4,5-di-p-tolylimidazole (QTI), chromium is demonstrated in the erythrocyte of the victim, in situ, providing a means of proving the hexavalent chromium ingestion.
Abstract: We describe the application of histochemical demonstration of chromium in a case of fatal ingestion of potassium dichromate in a suicide attempt. Using 2-(8-quinolylazo)-4,5-di-p-tolylimidazole (QTI), we could demonstrate chromium in the erythrocyte of the victim, in situ. This finding provides a means of proving the hexavalent chromium ingestion.
Journal Article•
Journal Article•
TL;DR: Both the cytotoxicity and mouse acute toxicity of potassium dichromate was larger than chromium chloride, and Potassium dichromates was mutagennic to Salomamella strains, but chromium chlorine was not.
Abstract: Purpose: To compare the cycotoxixity,mutagenncity and mouse acute toxicity between Chromium chloride and Potassium di chromate. Methods: MTT method for determition of CHL Cell IC 5 0, Salmonella mutagenicity test, and mouse acute toxicity test were used. Results: The CHL cell IC 50 of chromium chloride and potassium dichromate were 33.80 mmol / L and 8.02 μmol / L,r espectively; the LD 50 of chromium chloride and potassium dichro mate in mouse acute toxicity test were 2 143.3 and 171.0 m g / kg,respectively. Potassium dichromate meet the positive respond standards of Salmonella mutagenicity test whereas chromium chlor ide showed a negative results. Conclusion: Both the cytotoxicity and mouse acute toxicity of potassium dichromate was larger than chromium chloride. Potassium dichromate was mutagennic to Salomamella strains,but chromium chloride was not.
TL;DR: In this paper, Urazoles are oxidized to their corresponding triazolinediones in excellent yields with potassium dichromate in the presence of aluminium chloride under solvent-free conditions.
Abstract: Urazoles are oxidized to their corresponding triazolinediones in excellent yields with potassium dichromate in the presence of aluminium chloride under solvent-free conditions.
Patent•
11 Aug 2003
TL;DR: In this article, the authors proposed an anticorrosion protection of metals and can be used for preventing corrosion of carbon steels at a high temperature and a pressure equal to or less than 1.2 MPa in corrosion aggressive alkaline media which contain chlorine and sulphate ions and other aggressive components.
Abstract: The invention relates to anticorrosion protection of metals and can be used for preventing corrosion of carbon steels at a high temperature and a pressure equal to or less than 1.2 MPa in corrosion aggressive alkaline media which contain chlorine and sulphate ions and other aggressive components. Said invention can be used, in particular for protecting the inter-rail space (bottom) of autoclaves used for producing foam concrete against local and general corrosion and for anticorrosion protection of external surfaces of different pipelines, in particular heat pipelines used in severe corrosion conditions, dry cars used in ceramic brick production, against corrosion-erosion wear of car bottoms and for the similar. In the first embodiment, the inventive compound comprises asmol, sodium viscous grease, graphite, talcum powder, magnesium oxide, zinc oxide, a sodium molibdate and potassium dichromate mixture, a TAL-11 or IKB-4V organic inhibitor and a rubber solvent. In the second embodiment, the sodium viscous grease is substituted by stillage residues of synthetic fatty acids (SFA). In the third and fourth embodiments, the compound comprises said sodium viscous grease, stillage residues of synthetic fatty acids (SFA), asmol, graphite, talcum powder, magnesium oxide, zinc oxide, a sodium molibdate and potassium dichromate mixture, a TAL-11 or IKB-4B organic inhibitor and a rubber solvent at different quantity ratios.