Lead hydroxide, preparation

Prepare a solution of sodium plumbite by adding 10 per cent, sodium hydroxide solution to a few drops of about N lead acetate solution until the white precipitate of lead hydroxide initially formed just redissolves to a clear solution. Add 1 ml. of the fusion solution the presence of sulphiu- is indicated by a black precipitate of lead sulphide. 

PbF2 is readily prepared by the action of hydrogen fluoride on lead hydroxide, lead carbonate, or a-lead oxide. It can also be obtained by precipitation from lead nitrate or lead acetate solutions using potassium fluoride, ammonium fluoride, or ammonium bifluoride. 

The resulting -aminocaproic acid hydrochloride is treated in a manner similar to that used in the preparation of df-alanine (Org. Syn. Coll. Vol. i, 20). The hydrochloride is dissolved in r 1. of water in a 1.5-I. beaker and treated successively with 50 g. of powdered litharge, 25 g. of powdered litharge, 5 g. of freshly precipitated lead hydroxide, 25 g. of powdered silver oxide (Note 2), and finally hydrogen sulfide. During this procedure, the original volume is maintained by the addition of small amounts of water. 

Switzerland, and prepared according to a literature procedure, were used by the submitters without any noticeable difference. Lead tetraacetate was dried prior to use for at least 12 hours over potassium hydroxide and phosphorus pentoxide in an evacuated desiccator (12 mm.) that was protected from direct light. If well protected from moisture, lead tetraacetate can be kept for weeks in this way. However, after exposure to moisture in the air, lead tetraacetate usually turns brown from hydrolysis to lead hydroxide. The reactivity of such lead tetraacetate is diminished somewhat, but it can still be used. If the lead tetraacetate has turned black, the reagent should be recrystallized from glacial acetic acid and dried prior to use as described above. 

Aspartic acid.was first obtained by Plisson, in 1827, from asparagine by boiling it with lead hydroxide, and is usually prepared from this compound by hydrolysis with alkali or acid. 

Lead difluoride can be prepared by several methods. It is obtained by treating lead hydroxide or lead carbonate with hydrofluoric acid, followed by evaporation of the solution ... 

Lead monoxide also is produced by a modified Ball Mill process in which high purity lead balls placed in the mill are partially oxidized to produce black or grey oxide. Both the red and yellow form of the oxide may be prepared by alkaline dehydration of lead hydroxide, Pb(OH)2. 

To determine whether the mechanism for removal might be due to the precipitation of lead as lead hydroxide and subsequent removal by the resin acting as a filter, samples of water with a pH of 6-7 and a lead concentration of 25 /zg/L were prepared and filtered through a 0.45-/zm Metricel membrane filter. The results of this experiment were as follows lead concentration before passage, 26.1 /xg/L lead concentration after passage, 5.01 /xg/L. 

Lead iodide and lead hydroxide iodide3,28 29 are popular experimental systems. The lead iodide is best prepared at 45°, but room temperature can also be used. Thin hexagonal platelets of Pbl2 up to 8 mm in diameter have been grown in 3 weeks at 45°. Lower temperatures produce smaller, but thicker, crystals. Lead hydroxide iodide (PblOH) is formed in a basic gel in a test tube.30 If the gel is not alkaline, some Pbl2 crystals are also formed. 

The solution is evaporated to dryness under reduced pressure on a water bath. In order to remove as much hydrochloric acid as possible, the temperature of the bath is raised to 100° toward the end of the distillation. The residue of amino acid hydrochloride and inorganic salts is suspended in 500 cc. of absolute ethyl alcohol. The suspension is boiled on a steam bath for a short time, then cooled to room temperature and filtered on a Buchner funnel. The residue of inorganic salts is washed with 500 cc. of absolute ethyl alcohol. To the combined filtrates is added 400 cc. of ethyl ether (u. s. p. quality) in order to precipitate inorganic material. After several hours the mixture is filtered, and the residue is washed with a 5 2 mixture of absolute ethyl alcohol and ether. The filtrate is transferred to a 5-1. round-bottomed flask, about 200 cc. of water is added, and the liquids are removed by distillation under reduced pressure. The nearly dry residue is dissolved in 2 1. of water, and the solution is treated with an excess of freshly prepared lead hydroxide (Note 5). The suspension is diluted with water to a volume of about 3.5 1. and is then concentrated under reduced pressure, at as low a temperature as possible, to a volume of about 2 1. The suspension is then filtered with suction (Note 6), and the residue of lead salts is washed thoroughly with water. The cloudy filtrate, which still contains some free ammonia, is concentrated by distillation under reduced pressure to a volume of about 300-400 cc. The mixture is filtered, the filtrate is saturated with hydrogen sulfide gas, and the precipitate of lead sulfide is removed by filtration with suction (Note 6). The solution is now concentrated by distillation under reduced pressure on a water bath, and 1 1. of 95 per cent ethyl alcohol is added to the nearly dry residue of the amino acid. The suspension is boiled under a reflux condenser until nearly all the amino acid is dissolved, and the mixture is then allowed to cool to room temperature. The amino acid, which separates in the form of fine needles, is collected on a Buchner funnel and washed with a little 95 per cent ethyl alcohol. A second crop of... 

The lead hydroxide is prepared by adding 1.5 1. of a 2 N solution of sodium hydroxide (3 moles) through a dropping funnel to a continuously stirred solution of 569 g. (1.5 moles) of lead acetate, (CH3C02)2l)b-3H20, in 1.35 1. of water. The precipitate is collected on a 13-cm. Buchner funnel and washed well with water in order to remove water-soluble impurities. The paste of lead hydroxide is transferred to the solution that is to be freed of chloride ions. 

Ordinary glucose yields in addition to fructose and mannose a new ketose, pseudofructose, which has not yet been obtained in a pure state, and another substance, which is reducing but not fermentable, having the properties of a ketose and for whieh we suggest the name glutose. This substance can easily be prepared by the action of lead hydroxide on commercial fructose.. .. It can also be prepared by using invert sugar and lime. 

The kinetics of the electrochemical reduction of sulphamic acid giving sulphite ion and ammonium hydroxide have been studied polarographically in aqueous solution in the presence of various salts51. The electrodissolution of lead sulphide, prepared by fusion or by sintering in sulphamic acid, has been measured by cyclic voltammetric, potentiodynamic and potentiostatic methods52. 

A more sensitive test is attained by the use of sodium tetrahydroxo-plumbate(II) solution, prepared by adding sodium hydroxide to lead acetate until the initial precipitate of lead hydroxide has just dissolved ... 

This lead compound exists in two polymorphic forms tetragonal (P-PbO) and orthorhombic (a-PbO). The solubility of the two forms in water at 25 °C is 0.0504 g for a-PbO and 0.1065 g for 3-PbO [6]. Lead oxide forms lead hydroxides, 3Pb0-H20 and 5PbO H2O [7,8]. Lead oxide is hydrated forming Pb(OH)2, a compound of amphoteric nature. It dissociates to HPb02 and Pb(OH) ions. In the battery industry, lead oxide is obtained by partial thermal oxidation of lead and is ealled leady oxide , as it eontains between 73% and 85% PbO, the remaining part being non-oxidized lead. The basie eonstituent of leady oxide is tet-PbO, but orthorhombie PbO is also present, up to 5—6%. Leady oxide is used for tbe preparation of the pastes for lead—aeid battery plate production. 

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