Electrochemical Studies of Sodium Chloride as a Lewis Buffer for Room Temperature Chloroaluminate Molten Salts

Abstract

The reaction of equal molar quantities of 1-methyl-3-ethylimidazolium chloride (MEICI) with AICI~ results in the formation of a conductive ambient-temperature ionic liquid that, when investigated voltammetrically, exhibits 4.4V of electroinactivity between the reduction of MEI + and the oxidation of AICI4-. When unequal quantities of these reagents are used, however, the resulting melt has a much narrower electrochemical window due either to the formation of the acid A12CIC (which reduces to A1 at potentials that are nearly 2.0V positive of MEI § reduction) or the base C1-(which oxidizes to C12 at potentials that are 1.5V negative of AICI(oxidation). In this paper we investigate those equilibrium processes that control the chloroacidity in these ionic liquids. Specifically, we show that they undergo an acid exchange reaction A1CI((I) + AICI((I) ~ AI2C17-(/) + CF(/) K = 1.0 x 10 -16

Electrodeposition of Nano‐ and Microcrystalline Aluminium in Three Different Air and Water Stable Ionic Liquids

“…We found one reference in the literature where a series of N-alkyl-N-methylpyrrolidinium halides are investigated as a new class of cationic surfactants for a variety of applications. [34] Viscosity effects alone are rather unlikely as the viscosities of AlCl 3 In this mixture, aluminium can then be deposited even if the liquid is cooled down to room temperature. Figure 8 a exhibits the cyclic voltammogram of the ionic liquid trihexyl-tetradecyl phosphonium Tf 2 N containing 4 m AlCl 3 made at 150 8C and cooled down to 25 8C on a gold substrate at 25 8C.…”

“…[2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] It was reported in ref. [21] that bulk nanocrystalline aluminium can be electrodeposited from a Lewis acidic ionic liquid based on AlCl 3 (55 mol %) and 1-ethyl-3-methylimidazolium chloride ([EMIm] + Cl À ) under galvanostatic conditions with or without addition of nicotinic acid.…”

“…The first air and moisture stable imidazolium-based ionic liquids with either tetrafluoroborate or hexafluorophosphate as anions were reported in 1992 by Wilkes and Zaworotko. [22] Then, several liquids consisting of 1-ethyl-3-methylimidazolium, 1,2-dimethyl-3-propylimidazolium, or 1-butyl- 1 3 C À ], were found and received much attention because of their low reactivity against moisture. [23][24][25] The advantages of these ionic liquids compared to chloroaluminate ionic liquids are that they are water and air stable, easy to purify as well as, in most cases, easy to dry to water contents below 1 ppm.…”

A promising method for electrodeposition of aluminium on stainless steel in ionic liquid

“…9,[33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48] These ILs are mixtures of aluminium chloride and an organic halide (RX) and display adjustable Lewis acidity over a wide range of the molar ratio of AlCl 3 to RX. 49 Previous studies show that electrodeposition of Al can only be performed in acidic electrolytes, in which the electroactive Al 2 Cl À 7 , the only reducible aluminium containing species, are responsible for the electrodeposition according to the following reaction 47 :…”

Mechanism of Electrochemical Al Deposition from Room-Temperature Chloroaluminate Ionic Liquids

“…13 It is ordinary to expect that both Al 2 Cl 7 -and AlCl 4 -, the major anionic components participating in Al deposition and dissolution (Eq. (1)), 14,15 form the closest layer for the electrolyte-side capacitance region in this positive potential range. The anionic composition at the very first layer, throughout the positive potential region, is varying with the potential and the contribution from the larger Al 2 Cl 7 -ion, responsible for Al deposition, is keep increasing as the potential is scanned negatively.…”