Castner-Kellner cell

Castner-Kellner cell An electrolytic cell for the production of sodium hydroxide. ... 

Castner Kellner Cell.—Besides those cells already described, the object of which is to produce oxygen and hydrogen, there are some which, thongh not designed for the production of hydrogen, yield it as a by-product... 

Chlorine gas is produced by the electrolysis of brine (sodium chloride) in Castner-Kellner cells (first operated in 1886), the main purpose of which is the production of sodium hydroxide solution. Williams (1972, p98) reports that the extent to which the Castner-Kellner process was worked in Britain depended on the ability to dispose of the chlorine. In this light the production of chlorinated organic compounds can be seen as a response to the need to use chlorine. The argument that we need to produce chlorinated organic compounds to use up chlorine was indeed put to me by manufacturers of polyvinyl chloride (PVC) at a DETR-organized seminar on the lifecycle assessment of PVC in July 2001 PVC is the only product made in sufficient quantities to use up all the chlorine produced by other processes. This suggests that if a particular use of a chemical is stopped, because there is a better (less hazardous) way of achieving that purpose, it will have knock-on effects on the availability of chemicals that are co-produced... 

Another somewhat more complicated cell for the production of chlorine and sodium hydroxide by the electrolysis of sodium chloride solution is the Castner-Kellner cell, which employs a liquid mercury cathode. 

Castner cell — (also Castner-Kellner cell) Electrochemical cell employed in sodium winning by electrolysis of molten NaOH. According to... 

At what rate, in grams per hour, would chlorine be produced in a Castner Kellner cell by a current of 10,000 amps ... 

Perfluorinated polyethers have also gained importance as actively functional materials. Ionic polymer membranes (e.g. DuPont s Nafion ) based on sulfonic acid-derivatized perfluoropolyethers have been used for nearly 30 years as ion-con-ducting membranes in chloralkali electrolysis cells, replacing the large amounts of toxic mercury used until then in the classic Castner-Kellner cells (Scheme 4.8.). One of the earliest applications of Nafion was as a membrane in the hydrogen-oxygen fuel cells which powered the Apollo spacecraft carrying the first men to the moon. 

Castner-Kellner cell The cell used in the Castner-Kellner process. 

Griesheim (1) An early process for producing chlorine by electrolysis, developed by Chemische Fabrik Griesheim-Elektron, in Germany, and commercialized in 1890. The electrolyte was saturated potassium chloride solution, heated to 80 to 90°C. The byproduct potassium hydroxide was recovered. The process was superseded in the United States by several similar electrolytic processes before being ousted by the mercury cell, invented by H. Y. Castner and K. Kellner in 1892. See Castner-Kellner. 

Membrane cell A refinement of the Diaphragm cell process in which the diaphragm is made from a cation-exchange membrane. See also Castner-Kellner. 

Castner turned his interest to gold extraction, which required high-quality sodium hydroxide. Castner developed a three-chambered electrolytic cell. The two end chambers contained brine and graphite electrodes. The middle chamber held water. The cells were separated excepted for a small opening on the bottom, which contained a pool of mercury that served as the cell s cathode. When current flowed through the cell and the cell was rocked, sodium reduced from the brine came into contact with water in the middle cell to produce a sodium hydroxide solution. As Castner built his mercury cell, Kellner was working on a similar design. Rather than compete with each other, Castner and Kellner joined forces to establish the Castner-Kellner Alkali Company to produce sodium hydroxide, which competed with soda ash and potash as an industrial base, and chlorine, which was used primarily to make bleach. 

FIGURE 8.3 Vertical section of a Castner-Kellner rocking mercury cell, which demonstrates the principle of operation. The cell had provision for brine entry and removal of depleted brine from the left compartment, and for purified water entry and removal of sodium hydroxide from the right compartment. The eccentric revolved slowly to move the mercury on a regular basis between the two compartments. A cell divider extended close enough to the bottom of the cell to maintain a mercury seal, which prevented any mixture of the water phases of the two compartments. 

The first operating membrane cell was the rocking cell, largely developed by Baker, who was Castner s chief chemist, at Oldbury, and later at Runcorn. The history of the Castner Kellner plant at Runcorn gives the history of the development of the mercury cell, and indicates the way in which a technology has developed in the drive to increase production quantities and efficiencies while minimizing capital costs. 

Franz Frederick Exner developed a rotating anode expressly for industrial analytical practice that greatly reduced the time needed for analysis. The next year, Smith and another doctoral student, Joel Henry Hildebrand, created a double-cup mercury cathode by explicitly borrowing the basic operating principle of Dow Chemical Company s Castner-Kellner electrolytic cell. These inventions illustrate the interrelationship between industrial and academic science in the early twentieth century that produced a flow of ideas and methods in both directions. 

Hildebrand based his double-cup mercury cathode on the Castner-Kellner process for the industrial production of caustic soda. This process, which has been called the most elegant electrolytic process ever invented," was patented in 1894 by Hamilton Castner, an American analytical chemist. By 1902, Castner had increased its efficiency to 90 percent. The heart of the process was Castner s "rocking" mercury cell. The cell had two chambers through which mercury moved back and forth, continuously removed metallic sodium from the decomposing chamber, thus preventing the recombination of the sodium and chlorine. (24)... 

Castner-Kellner process The process of electrolysis of brine between graphite anodes and a flowing mercury cathode in a cell. 

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