The polarography of beryllium halides in acetonitrile

1967 ◽  
Vol 20 (2) ◽  
pp. 211 ◽  
Author(s):  
PJ Shirvington ◽  
TM Florence ◽  
AJ Harle
Keyword(s):  
Dissociation Constants ◽  
Experimental Results ◽  
Acid Dissociation ◽  
Polarographic Reduction ◽  
Insufficient Evidence ◽  
Acid Dissociation Constants ◽  
Beryllium Chloride ◽  
Halogen Acid

Polarographic reduction steps for various beryllium salts in acetonitrile have been recorded in tetrapropylammonium perchlorate, chloride, bromide, and iodide supporting electrolytes. The experimental results indicate that free halogen acid (which is strongly associated in acetonitrile) is produced as a result of solvolysis of beryllium. The concentration of water affects the degree of solvolysis by altering the halogen acid dissociation constants. A water to beryllium ratio of 4 : 1 brings about almost complete (99%) solvolysis of 3mM beryllium chloride. However, insufficient evidence was obtained to prove conclusively that water was the solvolytic agent.

Substituent effects on polarographic reduction of some photographic color intermediates

1976 ◽  
Vol 54 (8) ◽  
pp. 1205-1210 ◽  
Author(s):  
Ahmad S. Shawali ◽  
Bahgat E. El-Anadouli
Keyword(s):  
Dissociation Constants ◽  
Substituent Effects ◽  
Protonated Form ◽  
Acid Dissociation ◽  
Polarographic Reduction ◽  
Substituent Constant ◽  
Acid Dissociation Constants ◽  
Controlled Potential Electrolysis ◽  
Half Wave ◽  
Controlled Potential

Polarographic reduction of two series of benzoylacetanilides has been investigated in 40% (by volume) ethanolic Britton–Robinson buffers. One series (A) contains substituents on the anilide moiety, and the second (B) has substituents on both the anilide and benzoyl moieties. Polarographic controlled-potential electrolysis data indicate that the electroactive species in both series is the protonated form (ArCOCH2CONHAr′)H+. The reduction half-wave potentials of anilides of series A were found to be independent of the nature of the substituent, whereas those of series B show a good linear relationship when plotted vs. the σ substituent constant of the substituent on the benzoyl moiety (ρ = 0.284, r = 0.995). Values of the acid dissociation constants of the keto (K1) and enol (K2) tautomers of the anilides of series A were calculated; unlike their E1/2 values, the pK1 data show a linear correlation with the Hammett substituent constant, σ. The pK2 values show, however, little variation with σ.

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