Lead Acetate Oxide, Brown

Lead Orthoarsenite, Pb3(As03)2, is obtained as a white precipitate on adding a solution of basic lead acetate to a boiling aqueous solution of arsenious oxide,9 or of potassium tetrarsenite,10 or by the action of an alkali plumbite on an alkali arsenite.11 When dried in a dark air oven the arsenite remains white, but when exposed to light some specimens turn brown, a change which has been attributed to reduction of the lead to suboxide,12 but some arsenate and free arsenic are formed. All specimens... 

Dilute hydrochloric acid Lead (II) acetate or nitrate Cobalt nitrate Mercury Hypochlorites, OCh Yellow coloration, followed by chlorine gas evolution Brown lead (IV) oxide forms upon heating Black precipitate of cobalt (II) hydroxide On shaking slightly acidified solution of a hypochlorite with Hg, a brown precipitate of mercury (II) chloride is formed... 

Lead Dioxide. Lead oxide brown lead peroxide lead superoxide. 02Pb mol wt 239.21. O 13.38%, Pb 36.62%. Occurs in nature as the mineral plattnerite. Lab prepn from lead acetate and calcium hypochlorite Newel], Maxson, Inorg. Syn. 1, 45 ( 939) by hydrolysis of lead acetate Kuhn, Hammer, Ber. 83, 413 (1950). 

The presence of leucin and tyrosin in the urine may be detected as follows the freshly collected urine is treated with basic lead acetat filtered, the filtrate treated with HaS, filtered from the precipitated lead sulfid, and the filtrate evaporated over the water-bath leucin and tyrosin crystallize they may be separated by extraction of the residue with hot alcohol, which dissolves the leucin and leaves the tyrosin. The leucin left by evaporation of the alcoholic solution may be recognized by its crystalline form and by the following characters (1) a small portion is moistened on platinum foil with HNOa, which is then cautiously evaporated a colorless residue remains, which, when warmed with caustic soda solution, turns yeUow or brown, and by further concentration is converted into oily drops, which do not adhere to the platinum (Scherer s test) (2) a portion of the residue is heated in a dry test-tube it melts into oily drops, and the odor ofainylamin (odor of ammonia combined with that of fusel oil) is observed (3) if a boiling mixture of leucin and solution of neutral lead acetate be carefully neutralized with ammonia, brilliant crystals of a compound of leucin and lead oxid separate (4) leucin carefully heated in a glass tube, open at both ends, to 170° (338° F.), sublimes without fusing, and condenses in flocculent shreds. If heated beyond 180° (356° F.), the decomposition mentioned in (2) occurs. 

F. H. Storer obtained chromyl chloride. H. Moissan, 0. Popp, etc., found that it is soluble in sulphuric acid. W. Manchot and R. Kraus found that when warmed with sulphur dioxide, sulphur trioxide is formed and warm sulphurous acid is converted into sulphuric acid. C. W. Eliot and F. H. Storer, 0. Popp, etc., observed that chromic dioxide readily dissolves in dU. nitric acid the soln. is reddish-brown, and gives a dirty green precipitate with ammonia. W. Manchot and R. Kraus found that cone, nitric acid converts the dioxide into chromic acid. E. Hintz found that it is scarcely attacked by phosphorus pentachloride at 250°. A. Maus stated that a little arsenic acid converts the dioxide into chromic arsenate, which is soluble in an excess of arsenic acid. The dioxide is insoluble in ether, acetone, and other organic liquids and 0. Popp said that the dioxide dissolves with difficulty in acetic acid. M. Kriiger, W. Manchot and R. Kraus, etc., observed that boiling potassium or sodium hydroxide converts the dioxide into a soln. of alkali chromate, and a precipitate of hydrated chromic oxide. This simultaneous oxidation and reduction furnishes an illustration of the acidic and basic properties of chromium dioxide. A. Maus found that when digested with lead acetate in... 

As contrasted with the vigorous catalytic hydrogenation, the reduction with LiAlH4 is unlikely to lead to the complete elimination of the oxido oxygen. Sec.-tert. epoxides form tert. carbinols in most cases, while a sec. hydroxyl group is formed by acid catalytic hydrogenation.—E a-ChoIesterol oxide acetate 3yJ,5-dihydroxycholestane. Y. 95%. (F. e. s. P. A. Plattner, H. Heusser et al., Helv. 32, 587,1070 (1949).) s. a. 4, 50 L. W. Trevoy and W. G. Brown, Am. Soc. 71, 1675 (1949)... 

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