Electrolysis of Methylmagnesium Halides in Ether Solutions

Abstract

Vol. 58 chloride ceased water was added, the carbon tetrachloride layer removed and a saturated solution of salt added to the aqueous layer. About 25 g. of the sodium sulfonate was obtained. The loss in weight of the air-dried salt when heated in an oven at 120°indicated the presence of one molecule of water of hydration. The dry salt was analyzed for sodium.Anal. Caled, for CizHrOiSjNa: Na, 7.61. Found: Na, 7.66.Refluxing the dry sodium salt with excess phosphorus oxychloride gave the sulfonyl chloride which separated from petroleum ether as a light yellow solid that melted at 127-128°.

Electrochemistry of Organomagnesium Compounds

“…The relationships shown in Figure 3 can be explained by a similar reasoning. Electrochemical efficiency, calculated as the number of methyl groups per Faraday, decreases in the order Cl > Br > I and also decreases linearly with increasing concentration (the formation of MeX at an anode followed by a regeneration of 5 at a cathode was suggested 19 to explain the last observation). A decrease in electrochemical efficiency Table 4).…”

“…Evans and coworkers considered 15,19,21 that the cations, RMg + and MgX + , formed in simple ionization reactions 3a-3d, are coordinated with the Et 2 O molecules and are relatively small, whereas the anions are large in size due to a coordination with 1, 5 and MgBr 2 . These processes can be summarized by a simplified equilibrium (equation 4) for Grignard reagents 5 19,21 and by the equilibrium in equation 5 for 1 33,34 , but the participation of anions R 2 MgX − was also considered 17 as well as the equilibrium (equation 6) for 1e 33 . Moreover, a nonlinear increase in the logarithm of the equivalent conductivity of 1e solutions in 1,4-dioxane with log c found by Strohmeier 33 is no domination of a simple equilibrium.…”

“…In that case the electrochemical yield of the electrolysis, given as moles of 14 per 1 Faraday, is equal to 43.8% (Table 4), close to the theoretical value of 50%. The formation of 13 at lower concentrations was explained 19 by the H atom abstraction from Et 2 O molecules in equation 10a. The above reaction can also explain the formation of 15, ethanol (19) and i-propanol (20), which were determined experimentally in small amounts, because on the basis of a pyrolysis of ethers, the formation of EtOMgX and Me 2 CHOMgX were predicted 19 .…”

“…The relationships shown in Figure 4 can be explained taking into account that an increase in current density results 19 in an increase in the concentration of 12a radicals at the electrode; hence their coupling (equation 10d) to 14 is more favored than the reaction with solvent molecules (equation 10a). The relationships shown in Figure 3 can be explained by a similar reasoning.…”

“…Reactions of Ph ž radicals (12h) formed at anodes yield 23 styrene (30), biphenyl (31), pterphenyl (32), insoluble hydrocarbon of high molecular weight and, in smaller amounts, benzene (33) as well as ethanol (19). 30 was the main product for substituted reagents 5q and 5r but for unsubstituted 5e only if the current efficiency, Y el , was low.…”