Sodium amalgam decomposition

The decompositions which its salts undergo bear out this inter-pietadon of its compositioa Thus the decompdation of the free add into sulphur and sulphurous acid hem already been mentioned and when a solution of sodium thiosulphate is treated with sodium amalgam, sodium sulphite and sodium sulphide are formed (Sprmg) thus... 

Fig. 7. Mercury cathode electroly2er and decomposer (11) 1, brine level 2, metal anodes 3, mercury cathode, flowing along baseplate 4, mercury pump 5, vertical decomposer 6, water feed to decomposer 7, graphite packing, promoting decomposition of sodium amalgam 8, caustic Hquor exit 9, denuded mercury 10, brine feed 11, brine exit 12, hydrogen exit from decomposer 13, chlorine gas space 14, chlorine exit 15, wash water.

The action of liquid sodium amalgam on trimethylchlorosilane (34a, 34b) or -bromosilane (207) at room temperature results in the exclusive formation of bis(trimethylsilyl)mercury, [(CH3)3Si]2Hg, which is relatively stable to heat. This compound, however, undergoes decomposition on heating at 100°-160° C for a day to give hexamethyldisilane in quantitative yield (9, 34a, 34b, 207). 

The treatment of the product of the sodium hydride or sodium amalgam reaction described above with liquid hydrogen chloride at low temperature produces an extremely unstable boron hydride which is shown to be octaborane(14) by elemental analysis and boron-11 nmr 223>. This new hydride decomposes quantitatively to octaborane(12) and hydrogen in minutes at room temperature. The structure proposed 223> on the basis of the boron-11 nmr spectrum violates the topological principles based on hydrogen atom crowding 141> and is thus consistent with this facile decomposition. 

It was found impossible to measure the rate of decomposition by the evolution of gases because the release of these gas bubbles is very slow and erratic. The course of the reaction was followed by analyzing samples for the ammonium ion. Small amounts of the decomposing amalgam were forced through a capillary tube into a chilled solution of an iodate. The ammonium reacted with iodate ion to give iodide ion. The solution was then acidified with acetic acid and the iodine distilled out, collected and titrated with sodium thiosulfate. The method was checked with samples... 

The possibility of preparation of sodium or potassium amalgams by an electrochemical process is technically utilized for the production of alkaU hydroxides by decomposition of amalgams with water. 

The theoretical decomposition voltage of sodium chloride may be calculated as the sum of the reversible oxidation potential of the chlorine electrode and the reversible reduction potential of the amalgam electrode. 

The computed value E1 indicates the theoretical decomposition voltage of sodium chloride in a solution with unit activity of both sodium and chloride ions if a reversible insoluble anode and a reversible amalgam cathode which contains 0.206 per cent of Na are used (at a temperature of 25 °0). 

Fig. 99, Diagrammatic representation of electrolyzer and decomposition trough. Z — Current source, E% — Electrolyzer, 12 — Decomposition trough, A - Graphite anode, K — Graphlto grid, Ei — Sodium chloride decomposition voltage, Et — Amalgam cell voltage.

A rotating shaft coupled with a rubber coated drum passes through the stuffing boxes in the walls.pf the quadrangular middle compartment. Five steel cathode disks are fixed on the shaft and are approx. 1800 mm in diameter. The rotor operates at 7 r. p. m. In order to reduce the dead volume of the idle mercury in the lower part, semicircular rubber-coated iron insertions aro placed between the disks. The rest of the space is filled with mercury (total weight approx. 2000 kg) into which the lower parts of the rotary disks are dipped. The mercury inlet opens into the middle section. The mercury containing sodium amalgam leaves the middle section on the opposite side to be then transported into the decomposition vessel. 

Amino-4-methoxyphenylarsinic acid is obtained when the preceding mtro-acid is reduced with 5 per cent, sodium amalgam in boiling methyl alcohol. It separates from water in clusters of colourless needles, melting with decomposition at 198° C., and can be acetylated. 

Aminothienyl-2-arsinlc acid results when the preceding acid is reduced by sodium amalgam in methyl alcohol solution. It crystallises in pale yellow, microscopic laminae, decomposing at 194° C. It is readily diazotised and coupled with amines and phenols, yielding highly coloured compounds. The acetyl derivative forms white prisms, M.pt. 134° C., with decomposition. 

Sodium amalgam acts on (Me2ClSi)2CH2 to produce greenish-yellow crystals, sublimable in vacuo at 100°C without decomposition, comprised of eight-membered rings (I) with linear Si—Hg—Si bonds ... 

Considering reactions (1) and (2), chlorine and sodium amalgam are formed in the electrolysis cell. The amalgam can be extracted and undergoes a decomposition reaction in a separate reactor (decomposer, denuder). The electrocatalytic process is... 

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