Electrolytic preparation

Electrolytic Preparation of Chlorine and Caustic Soda. The preparation of chlorine [7782-50-5] and caustic soda [1310-73-2] is an important use for mercury metal. Since 1989, chlor—alkali production has been responsible for the largest use for mercury in the United States. In this process, mercury is used as a flowing cathode in an electrolytic cell into which a sodium chloride [7647-14-5] solution (brine) is introduced. This brine is then subjected to an electric current, and the aqueous solution of sodium chloride flows between the anode and the mercury, releasing chlorine gas at the anode. The sodium ions form an amalgam with the mercury cathode. Water is added to the amalgam to remove the sodium [7440-23-5] forming hydrogen [1333-74-0] and sodium hydroxide and relatively pure mercury metal, which is recycled into the cell (see Alkali and chlorine products). 

Supporting electrolyte. Prepare a supporting electrolyte composed of l.OOM pyridine and 0.50M chloride ion, adjusted to a pH of 7.0 0.2 for use with a silver anode, or LOOM pyridine, 0.30M chloride ion and 0.20M hydrazinium sulphate, adjusted to a pH of 7.0 0.2, for use with a platinum cathode. A small background current is obtained with the latter. 

Reagents. Supporting electrolyte. Prepare a 0.1M phosphate buffer of pH = 8 containing 0.1M potassium iodide and 0.025 M potassium tartrate (0.17 g Na2HP04,12H20, 3.38 g NaH2P04,2H20, 4.15 g KI and 1.5 g potassium tartrate, in 250 mL of water). 

Reagents. Supporting electrolyte. Prepare 0.2M potassium bromide from the analytical grade salt. 

Reagent. Supporting electrolyte. Prepare a 0.5M potassium nitrate from the pure salt for chloride determinations the solution must be prepared with a mixture of equal volumes of distilled water and ethanol. 

Reagent. Supporting electrolyte. Prepare a 0.05 M sodium bromide solution. 

The dendritic growth of lithium was suppressed on a lithium electrode surface modified by an ultrathin solid polymer electrolyte prepared from 1,1—difluoro-ethane by plasma polymerization [114]. 

Ion exchangers are polymer electrolytes prepared a priori as insoluble solids (salts, acids, bases hydrated, possibly gel-Uke). Their polymer backbone is three-dimensional. Many are polyvinyl compounds (substituted polyethylenes) having the general formula [-CH2-CXH-] , where different substituents X lead to rather different products ... 

The electrolytic preparation of cyanuryl chloride from a chloride and hydrogen cyanide is dangerous. 

Attwood PA, McNicol BD, Short RT. 1980. Electrocatalytic oxidation of methanol in acid electrolyte—Preparation and characterization of noble-metal electrocatalysts supported on pretreated carbon-fiber papers. J Appl Electrochem 10 213-222. 

Several modifications of the Simmons-Smith procedure have been developed in which an electrophile or Lewis acid is included. Inclusion of acetyl chloride accelerates the reaction and permits the use of dibromomethane.174 Titanium tetrachloride has similar effects in the reactions of unfunctionalized alkenes.175 Reactivity can be enhanced by inclusion of a small amount of trimethylsilyl chloride.176 The Simmons-Smith reaction has also been found to be sensitive to the purity of the zinc used. Electrolytically prepared zinc is much more reactive than zinc prepared by metallurgic smelting, and this has been traced to small amounts of lead in the latter material. 

Electrolyte preparation (arsenic, selenium, and zinc) pH is slightly alkaline... 

Very recently, we reported liquid imidazole-borane complexes (scheme 5)57 that are air stable. Judging from their polarity and viscosity (Table 3), they are expected to be a new class of solvent or electrolyte. Preparation of polymer homo-logues of imidazole-alkylborane complexes will also be reported elsewhere in the near future. 

Figure 7 Temperature dependence of ionic conductivity for lithium borate polymer electrolytes prepared via polymer reactions.

There is a risk of generating hydrogen/chlorine/oxygen mixtures during electrolytic preparation from brine. An explosive limits diagram for this ternary system is given. 

Chlorine (Cl), 6 130-211 9 280. See also Inorganic chlorine XeCl laser addition to fullerene, 12 240-241 analytical methods, 6 202 bleaching agent, 4 50 capacities of facilities, 6 193-198t catalyst poison, 5 257t chemical properties, 6 133-138 diffusion coefficient for dilute gas in water at 20° C, l 67t diffusion coefficient in air at 0° C, l 70t for disinfection, 8 605 economic aspects, 6 188-202 electrolytic preparation/production of, 12 759 16 40 end uses, 6 134-135 in fused quartz manufacture, 22 413 generating from hydrogen chloride, 13 833... 

An electrolyte preparation contains 74 mg% of Fe++ ions. Express this concentration in terms of milliequivalents/liter. 

Docusate salts Bisacodyl Polyethylene glycol-electrolyte preparations... 

Also, the influence of aluminum sulfate, animal glue, and an extract of horse-chestnut nuts on zinc electrowiiming from a weak acidic sulfate electrolyte prepared from an industrial waste product was investigated [401]. The use of additives mixture has a beneficial effect on zinc electrowinning and results in smooth, slightly bright zinc deposits. 

Electrolytic processes for the perchlorates.—F. von Stadion found that if an aq. soln. of chlorine dioxide be included in Volta s circuit, at first very little gas is developed, but after some hours, oxygen and chlorine appear at the anode, and hydrogen at the cathode. The volume of hydrogen so obtained is nearly twice that of the oxygen. After some time the soln. is decolorized, and transformed into perchloric acid. In 1857, A. Riche 18 prepared perchloric acid by the electrolysis of hydrochloric acid, or of an aq. soln. of chlorine and ten years earlier, H. Kolbe prepared potassium perchlorate by the electrolysis of an aq. soln. of potassium chloride—acidified with sulphuric acid—and of potassium trichloro-methyl-sulphonate. H. Kolbe (1846), a pioneer in the electrolytic preparation of compounds, specially noted that the formation of perchloric acid is always preceded by that of chloric acid, and stated ... 

In general, in an electrolytic process, oxygen is evolved at the anode, and hydrogen at the cathode. If these electrodes are in different compartments, with a suitable electrolyte we may expect to have reactions of oxidation taking place in the anode compartment and reactions of reduction in the cathode compartment. In inorganic chemistry, the more successful electrolytic preparations are chiefly those of oxidation while in organic chemistry, reactions of both oxidation and reduction are often successful. In inorganic chemistry, reactions of reduction are usually effected in simple ways. The several units of the necessary apparatus are connected as shown in Fig. 10. 

References Elbs, Electrolytic Preparations (1904) Mantell, Industrial Electrochemistry (1931 Perkins, Practical Methods of Electrochemistry (1905). 

Fig. io.—Apparatus for The most favorable current electrolytic preparations.. . . . ... 

The formation of the perdisulphuric acid in the electrolysis of sulphuric acid is due to the coupling together of the discharged HS04 ions at the anode it is for this reason that very dilute sulphuric acid, which is mainly dissociated into H" and S04" ions, is unsuited for the electrolytic preparation. A 70 per cent, yield is obtained by large scale production from acid of strength 500 grams per litre.5... 

The Perdisulphates.—A similar process to the electrolytic preparation of perdisulphuric acid is possible for the preparation of the perdisulphates. The corresponding alkali hydrogen sulphate or a mixture of the normal sulphate and sulphuric acid in cold aqueous solution is electrolysed in a cell so arranged that the anode and cathode are... 

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