Manganates tests

A particular interest for clinical applications was a possibility for detection of dopamine by its oxidation on nickel [19], cobalt [65], and osmium [66] hexacyanofer-ates. Except for oxidation of dopamine, cobalt and osmium hexacyanoferrates were active in oxidation of epinephrine and norepinephrine. For clinical analysis it is also important to carry out the detection of morphine on cobalt [67] and ferric [68] hexacyanoferrates, as well as the detection of oxidizable amino acids (cystein, methionine) by manganous [69] and ruthenium [70] hexacyanoferrate-modified electrodes. In general, oxidation of thiols was first shown for Prussian blue [71] and nickel hexacyanoferrate [72], This approach has been used for the detection of thiols in rat striatum microdialysate [73], Alternatively, the detection of thiocholine with Prussian blue was employed for pesticide determination in acetylcholine-esterase test [74],... 

Properties of Manganates. 1. Pour 1 ml of the prepared potassium manganate solution into each of two test tubes, greatly dilute the solution in one tube with water, add 2-3 ml of water to the other tube and pass a stream of carbon dioxide through it. How and why does the colour of the solution in both cases change Write the equations of the relevant reactions. 

Barium manganate [7787-35-] J M 256.3. Wash with conductivity H2O by decantation until the supernatant gives a faint test for Ba . Remove excess H2O in vac (IMPORTANT), then heat at 100° and the last traces of H2O are removed in a vac desiccator over P2O5. Store over KOH. It disproportionates in hot H2O or dil acid to Ba(MnO2)2 and Mn02, and is a mild oxidant. [7ACS 44 1965 1924-, Inorg Synth 11 56 I 960]. 

A variation of the above tests is that devised by Lenher.1Ms which depends on tho low solubility of certain metal ions in alkaline solution. Treatment of an epoxide with concentrator aqueous man ganoua chloride, for example, causes the gradual appearance of a manganous hydroxide precipitate as OH ions are liberated (Eq. SS i). Other halides examined by Lenher but found to he less effective wore nine chloride, ferrous chloride, and stannous chloride. 

Sulfite (S032") Add dilute hydrochloric acid, warm gently and test for the presence of sulfur dioxide Sulfur dioxide produced will turn acidified aqueous potassium manganate(vn) from purple to colourless... 

P 51] The reduction of a solution with potassium permanganate in alkaline ethanol was used as a test reaction [141]. The course of this reaction can be simply followed by visual observation of the color changes. The reactant solution is purple, the intermediate manganate is green and the final product, manganese dioxide, is yellow to brown. One drawback relates to the precipitation of the product, which needs a cleaning step with sulfuric acid for dissolution. 

Tetryl or Picrylnitromethylamine(pp 488-89) can be detected by treating(in a micro test tube) a drop of benzenic soln of the sample with powdered manganous sulfate filling the tube to 2/3 of its capacity. After evapg benzene, the tube is immersed (after covering its mouth with a disk of filter paper moistened with Nessler soln) into a bath preheated to 140° and the temp is raised to 150°. A gray or black Stain on the paper appearing within 5 mins indicates the presence of a nitramine, such as tetryl. 

The oxidation of S(IV) is a first order reaction with respect to S(IV) (2,3). This reaction is accelerated by the presence of metallic ions such as ferric and manganous ions which act as catalysts (4-8). Therefore, the effect of the metallic ions on the oxidation of S(IV) was investigated by using test solutions. Table I shows experimental conditions for the oxidation of S(IV) in test solutions. The pH values of synthetic rain water samples were adjusted between 3 and 6. S(IV) concentration in the test solutions was adjusted to 12.5 yM most of S(IV) existed as bisulfite at pH 3-6 (9). The rate of S(IV) oxidation was measured using ion chromatographic analysis. The pH of each test solution was adjusted by using a buffer. 

The result of measurements of the rate constant and half life of S(IV) in the test solutions are shown in Table II. The rate of oxidation of S(IV) in the solution without a catalyst was 0.4-5.9 x 10 3 hr 1. The rate increases by 2 to 4 orders of magnitude in the presence of metallic ions, and a significant catalytic effect of ferric and manganous ions was found in these experiments. In the test solution containing both ferric and manganous ions, the rate enhancement was additive. 

The oxidation reaction of S(IV) in both test solutions and rain water was found to be a first order reaction. Metallic ions such as ferric and manganous ions strongly catalyze the oxidation of S(IV) in rain water. A correlation was found between the concentration of metallic ions and the rate of S(IV) oxidation. The rate constant for the oxidation of S(IV) was found to be 0.12-3.3 hr A (half life ... 

Oxidation of manganous salts in acid solution to red manganic salts is characteristic of true perphosphates. They should not give the characteristic tests of hydrogen peroxide with chromic acid or titanic acid. They oxidise acid aniline solutions to nitrosobenzene and gradually to nitrobenzene. 

Sodium carbonate bead tests The sodium carbonate bead is prepared by fusing a small quantity of sodium carbonate on a platinum wire loop in the Bunsen flame a white, opaque head is produced. If this is moistened, dipped into a little potassium nitrate and then into a small quantity of a manganese compound, and the whole heated in the oxidizing flame, a green bead of sodium manganate is formed ... 

A manganate is produced when a manganese compound is fused with potassium nitrate and sodium carbonate (see Section III.28, Dry tests). 

Action of heat When potassium permanganate is heated in a test-tube, pure oxygen is evolved, and a black residue of potassium manganate K2Mn04 and... 

Before solvent extraction, the feed was treated with manganous nitrate and less than equivalent permanganate to convert plutonium to Pu(VI). Tests in miniature mixer-settlers with synthetic feed solution but not containing Cf showed acceptably small concentrations of actinides in the aqueous waste (1AW) and organic raffinate (1CW) streams, and also acceptable separation of plutonium from curium and americium. 

The Winkler test, or minor variations of it, is the standard wet chemical procedure for measuring the concentration of dissolved oxygen in water samples [24, 28, 29]. It uses a standard 300 mL BOD sample bottle, which is closed with a glass stopper with a polished cone-shaped end. This closure makes it possible to completely fill the bottle with the water sample and avoids any interference from bubbles of air which might otherwise be trapped in the bottle. Initially a white precipitate of manganous hydroxide is prepared in the BOD bottle (Eq. 4.17). 

If there is any dissolved oxygen in the water sample being tested, it oxidizes the manganous hydroxide to a brown suspension of manganic hydroxide in the test solution (Eq. 4.18). 

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