Electrolysis nitrogen reduction

Electrolytic reduction involves electrolysis of partially molten calcium chloride at 780° to 800°C in a graphite lined steel vessel. The method requires precise control of temperature and current. The sohd deposit of metal produced may contain entrapped salt and impurities such as chlorine and nitrogen. It is re-melted to reduce impurity levels. 

The imido complex [Mo2(cp)2(/r-SMe)3 (/u.-NFl)]" " 25+ undergoes an irreversible one-electron (EC) reduction [70]. Controlled potential electrolysis afforded the amido analog [Mo2(cp)2(/x-SMe)3(/x-NH2)] 26 almost quantitatively after the transfer of IF mol 25+. The amido complex was not the primary reduction product the latter was assigned as a rearranged imide radical (Sch. 18), which is able to abstract a FI-atom from the environment (supporting electrolyte, solvent, or adventitious water) on the electrolysis timescale. In the presence of protons, the reduction of 25+ became a two-electron (ECE) process. This is consistent with the protonation at the nitrogen lone pair of the primary reduction product, followed by reduction of the resulting amido cation... 

The electrochemical reduction is best carried out using a controlled poten-tiostat and cell, as shown in Fig. 2. S7Fe203 (80 mg, 0.0S mmole) is dissolved in concentrated HC1 (10 mL) the resultant yellow solution is then evaporated to near dryness on a rotovap with a bath temperature of about 60°. The residue is diluted to 15 mL with water and transferred to compartment A of the electrolysis cell. Compartments B and C are immediately filled with 0.1 M UC104. The solutions are purged with argon (or nitrogen) for 10 minutes before electrolysis starts. 

The reduction of the tetrazoles [Eq. (60)] has been used as a model for optimization of the chemical yield using an undivided cell and constant current rather than constant potential electrolysis [285,286]. Electrolysis under air rather than under nitrogen lowered the current yield from 43% to 20% (assuming a 1-F process) but increased the product selectivity (from 50% to 94%), since the intermediate, partly hydrogenated fluorophenyl ring was dehydrogenated, probably by electrogenerated superoxide ion [286]. 

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