Mechanism of Dehydrobromination of 1,2-Dibromo-1-phenylethane under Conditions of Phase-Transfer Catalysis

Selective dehydrobromination of 1,2-dibromo-1-phenylethane to -bromostyrene was effected under conditions of phase-transfer catalysis in systems containing KOH, toluene, and tetraalkylammonium bromides. The high selectivity of the catalytic systems originates from stabilization by lipophilic cation of the phase-transfer catalyst of a E1cb-like transition state in the E2 mechanism. In the presence of a catalytic amount of lipophilic alcohols, phenylacetylene was obtained. Substrate activation by alcohol molecules is explained by enhancement of the acceptor power of halogen atoms due to solvation and by increased mobility of hydrogen atoms.     

Synthesis of aryloxyacetaldehydes and <Emphasis Type="Italic">N</Emphasis>-(aryloxyethyl)cyclohexanamine hydrochloroides

Oxidation of 2-(aryloxymethyl)oxiranes with periodic acid gave a series of aryloxyacetaldehydes which reacted with cyclohexylamine in THF, and subsequent reduction of Schiff bases thus obtained with sodium tetrahydridoborate resulted in the formation of the corresponding secondary amines which were isolated and characterized as hydrochlorides.     

Kinetics of Anodic Dissolution of Some Metals in Electrolytes Based on Complexes of Triethylaluminum with Alkali Metal Fluorides and Tetraethylammonium Chloride

The dissolution kinetics of M* anodes (M* = Al, Cd, Sn, Sb, Bi) during electrolysis of molten complexes M[Al₂Et₆] (M = Na, K, Rb, Et₄N; = F, Cl) is studied. Parallel dissolution paths are discovered: through a limiting discharge of electrolyte components and through a limiting electrooxidation of adatoms and clusters of M* present at the electrode surface. Substantiated is a mechanism of electrosynthesis of ethyl derivatives M*Et _n involving the formation of adsorbed complexes (M*Et_{1 k n – 1})_ads via the scheme AlEt₄ ^– + M* – e M*(Et)_ads + (AlEt₃); M*(Et)_ads + (AlEt₄ ^–) – e = M*(Et₂)_ads + (AlEt₃); ...; M*(Et _{n – 1})_ads + (AlEt₄ ^–) – e AlEt₃ + M*Et _n .