Anion interaction ethanol

A more sensitive alternative procedure for measuring the relative nucleophilicities of anions is based on reactions of triethyloxonium ions in ethanol at 0°C68. The probable cause of the greater sensitivity is cation-anion interactions, which make nucleophilic attack by anions (equation 13) relatively more favourable than attack by solvent (equation 14). The results (Table 5) show that tosylate anion is less nucleophilic even than nitrate ion. 

The partial inhibition of the hydrolysis observed at pH < 4, and the negative salt effect, may be attributed to a specific cation-anion interaction. The proposed mechanism receives further support from the observed effects on the hydrolysis rates of increased viscosity of the medium and of added inorganic nucleophiles. Hydrazine or alkylhydrazines cleave and recyclize 1,3,4-thiadiazolium salts (114) to 1,2- or l,4-dihydro-l,2,4,5-tetrazines (115) in high yield. The action of arylhydrazine results in the alternative recyclization of the probable intermediate ArNHN=CR2NR N=CR SH, to 4-amino-1,2,4-triazolium salts (116). 5-Amino-2-imino-3-phenacyl-l,3,4-thiadiazolines (117) isomerize in boiling ethanol to 5-amino-3-mercapto-l-phenacyl-l,2,4-triazoles (118). This example... 

Moving OH from 4- to 2-position slightly reduces the acidity for X = S or CH2, but increases it for X = SO, the pKu values (in 48% aqueous ethanol) being 9.17 and 9.04 respectively. This was attributed to the above interaction. On the other hand, moving OH from 4- to 2-position greatly reduces the acidity of the sulfone system (pKa values 8.69 and 9.10 respectively) and this was attributed to an inescapable unfavorable interaction of the negative oxygens of S02 with the O- in the anion. 

The cadmium electrodeposition on the cadmium electrode from water-ethanol [222, 223], water-DMSO [224], and water-acetonitrile mixtures [225-229] was studied intensively. It was found that promotion of Cd(II) electrodeposition [222] was caused by the formation of unstable solvates of Cd(II) ions with adsorbed alcohol molecules or by interaction with adsorbed perchlorate anions. In the presence of 1 anions, the formation of activated Cd(II)-I complex in adsorbed layer accelerated the electrode reaction [223]. 

The formation of a-naphthols of type 189 from 1-alkyl-substituted salts 30, on heating with dimethylamine hydrochloride in ethanol, occurs by another mechanism and will be explained in Section III,C,4,b,i. The interaction of l-aryl-3-carboxy-substituted salts 62 with secondary amines in benzene is initiated probably as in the reaction of these salts with primary amines, and the attack by the secondary amine on position 3 is the primary step of this reaction. However, since protonation of the intermediate anion 190, a masked acyl anion, becomes difficult, an interaction of this anion with the carbonyl group of the benzophenone fragment occurs (86KGS125). The enamines 191 thus formed are usually hydrolyzed on purification, yielding five-membered cyclic acyloins 192. 

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