Showing papers on "Sodium dichromate published in 1979"

Production of an ozone removal filter

Abstract: Production of a device or filter for removal of ozone from air, e.g. in aircraft cabins, by depositing an oxide film containing manganese dioxide on a substrate, particularly a light weight thermally stable substrate, e.g. polybenzimidazole, by treatment with a permanganate solution containing a soluble ceric salt such as ceric ammonium nitrate, and preferably also a dichromate such as sodium dichromate, to form a dense strongly adherent film or coating of MnO 2 , ceric oxide and preferably also chromic oxide, on the substrate. A solution containing an oxidizable organic component such as abietic acid can be first applied to the substrate, followed by treatment with the above permanganate solution.

Magnesium anodize bath control

Abstract: An analytical method to determine and control the chemical composition andoncentration of a magnesium anodizing solution consisting of three chemicals, sodium dichromate, ammonium bifluoride and phosphoric acid, such as in Chemical Treatment No. 17 of Dow Chemical Company, for example. Automatic pH titration is used to determine the amount of ammonium bifluoride (NH4 HF2) and phosphoric acid (H3 PO4) concentration at the same time and the concentration of sodium dichromate (Na2 Cr2 O7.2H2 O) is determined separately by the thiosulfate titration technique.

Metabolic activation and deactivation of mutagens and carcinogens.

Abstract: The activity of some mutagens has been investigated in the Salmonella test either in the absence or in the presence of fortified rat liver microsomal fractions, together with an NADPH-generating system. With respect to their metabolic reactivity, the compounds tested could be distinguished according to four reproducible trends: (a) conversion of inert compounds into mutagenic metabolites (e.g. 2-aminofluorene and benzo(a)pyrene); (b) further enhancement of mutagenicity (e.g. 1,2-epoxybutane); (c) no effect on mutagenicity (e.g. glycidol, folpet, nitrofurantoin and 2-nitronaphtalene); (d) slight decrease (e.g. 1,1,1-trichlor 2,3-propenoxide), marked decrease (e.g. sodium nitrite, 5-nitro-2-furoic acid and captan) or even complete reversal of mutagenicity (e.g. styrene oxide, sodium azide, sodium dichromate and other Cr6+ compounds). The Salmonella/microsome test was effective in discriminating not only the mutagenic activity but also the metabolic reactivity of structurally related chemicals (e.g. the fungicides captan and folpet). In some cases, mutagens were tested also in the presence of other biological preparations (e.g. rat muscle or lung microsomal preparations, human gastric juice, serum, plasma or erythrocyte lysates). The mutagenic and metabolic properties of largely used products (e.g. an antibacterial drug containing nitrofurantoin and laboratory reagents containing sodium azide) have been also checked. The mechanisms underlying the metabolic behaviour of some of the mutagens tested have been reported. The results obtained have been correlated with the literature data on their carcinogenicity. Although these in vitro findings are only indicative of the possible metabolic fate of mutagens in the whole organism, the observed effects may be useful in order to explain the epidemiological data and the results of animal tests, and to assess the possible health hazards of mutagens.

Production of chromium oxide

Abstract: PURPOSE:To prepare chromium oxide having quality characteristics for each purpose such as pigment with a little NH3 by mixing sodium dichromate contg. about 1 time as much inorg. acid as the dichromate by mol or less than 0.7 time as much NH4OH with the corresponding acid and NH4 salt or NH3, followed by calcination. CONSTITUTION:To sodium dichromate in which the molar ratio of H2SO4/ Na2Cr2O7 or HCl/na2Cr2O7 is about 1 and that of 2NH4OH/Na2Cr2O7 below 0.7, esp. 0.35-0.7, esp. 0.35-0.7 are added the corresponding acid and NH4 salt or NH3. In case of producing chrome green pigment, the blend is then calcined at 800- 1100 deg.C and thermally decomposed. The calcined product is washed with water to remove salts, and chromium oxide (Cr2O3) formed is recovered, dried, and pulverized to obtain a product.

Determination of tritium or deuterium in the methyl group of labeled organic compounds

Abstract: The determination of the isotopic content of C-methyl groups in selected tritium and deuterium labeled compounds by modification of the Kuhn-Roth method is presented. Oxidation of the deuterated or tritiated compound using a solution of sodium dichromate and sulfuric acid at 50–85°C allows isotopic assay of the C-methyl group as acetic acid.

Synthesis of leaf aldehyde

Abstract: The comparative oxidation of trans-hex-2-enol to leaf aldehyde has been effected with the aid of manganese dioxide, chromium oxide, and sodium dichromate in DMSO. It has been established that sodium dichromate in DMSO gives the best yield (not less than 80%) and a product of higher purity. It is a comparatively new reagent in organic synthesis. The use of sodium dichromate in DMSO is promising in the preparation of compounds requiring the use of mild conditions.