Electro-organic synthetic processes

Although the effect of temperature on each of the steps in an overall electrode process is readily predictable, it is surprising to find in the literature very few systematic studies of this variable or attempts to use it to change the rate, products or selectivity of an organic electro-synthetic process. A recent paper has, however, discussed equipment and suitable solvents for low-temperature electrochemistry (Van Dyne and Reilley, 1972a). 

Limitations to the acceptance of organic electrochemistry, particularly as a synthetic technique, may have been connected with the fact that electrode reactions are normally two-dimensional, i.e., they are restricted to a surface and therefore require mass transport (see elsewhere in this chapter) and also because many reactions yield a complex mixture of products when the electrolyses are carried out using a constant current. However, as early as 1898, Haber had pointed out the importance of control of the electrode potential for the overall process, in his work where nitrosobenzene, phenylhy-droxylamine and aniline were isolated selectively from the reduction of nitrobenzene. However, design of suitable controlled-potential equipment proved to be a practical barrier, even in laboratory studies, until 1942, when the potentiostat—an instrument capable of automatically controlling the electrode potential—was introduced.Without question, this instrument has facilitated electro-organic syntheses, mechanistic studies, and specific electrooxidation and electroreduction processes. More modern and electronically... 

Iodine — Iodine, L, is a halogen which occurs naturally mainly as iodide, I- [i]. Iodine (Greek ioeides for colored violet ) is a black solid with a melting point of 113.6 °C which is readily undergoing sublimation to form a violet gas. Iodine occurs in the oxidation states -1,0, +1, +3, +5, +7 and it possesses a rich redox chemistry [ii]. In aqueous solution the formation of I2 from I- occurs with a standard potential of 0.621V vs. SHE and this oxidation process is preceded by the formation of I3 with a standard potential of 0.536 V vs. SHE. For the reaction I2(cryst) + 2e - 21 E = 0.535 V. The I—/I3 redox couple is employed, for example, in solar cells [iii] and in long-lived lithium-iodine battery systems. The oxidation of I2 in organic solvents results formally in I+ intermediates which is a powerful oxidant and useful, for example, in electro-synthetic chemical processes [ii]. 

Hi redox couple is employed, for example, in solar cells [iii] and in long-lived lithium-iodine battery systems. The oxidation of I2 in organic solvents results formally in H intermediates which is a powerful oxidant and useful, for example, in electro-synthetic chemical processes [iij. 

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