Additional Solvent Ionizing Power Values for Binary Water- 1,1,1,3,3,3-Hexafluoro-2-propanol Solvents

Abstract

Abstract:Determinations of the specific rates of solvolysis of 1-adamantyl bromide and 1-adamantyl iodide in 1,1,1,3,3,3-hexafluoro-2-propanol-water mixtures, in conjunction with earlier reported values in 80% ethanol, have led to additional YBr and YI solvent ionizing power values. These new values will be especially important in avoiding multicollinearity when the extended Grunwald-Winstein equation (extended by addition of a term involving solvent nucleophilicity) is used to correlate solvent-induced changes in the specific rates of solvolyses involving a bromide or iodide ion leaving group.

Detailed analysis for the solvolysis of isopropenyl chloroformate

“…$$\text{log}(k/k_o)=lN+mY+c$$ N T scales based on the solvolyses of the S -methyldibenzothiophenium ion [35,36] have now become the recognized standards for considerations of solvent nucleophilicity and it has been previously show [37,38] that adamantyl derivatives provide better standard substrates for a leaving group X. Hence a series of Y X scales [37–43] are now available. Whenever the reaction center is adjacent to a π-system [44,45], or in α-haloalkyl aryl compounds that proceed via anchimeric assistance ( k Δ )[46], Kevill and D’Souza recommended [2,47–50] the addition of an additional aromatic ring parameter ( hI ) term to equation 1 give equation 2.…”

Correlations of the Specific Rates of Solvolysis of Aromatic Carbamoyl Chlorides, Chloroformates, Chlorothionoformates, and Chlorodithioformates Revisited

“…Fortunately, commercially available fluoroalcohols [2,2,2–trifluoroethanol (TFE) and 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP)] in varying proportions with water show very different relationships between N and Y values [8, 9] decrease. These fluoroalcohol-containing solvents play an important role in studies designed to allow a meaningful application of equation 2.…”

Correlation of the rates of solvolysis of α-bromoisobutyrophenone using both simple and extended forms of the Grunwald-Winstein equation and the application of correlation analysis to related studies

“…All of the integrated values from the, at least, duplicate runs are averaged and the average values together with the standard deviation are reported. Also presented within the table are the relevant solvent nucleophilicity ( N T )[6] and ionizing power ( Y Br ) [5,19,20] values used in the simple and multiple regression analyses, together, when both specific rates are available, with the ratio of the specific rate for the solvolysis of 2 relative to that for the corresponding solvolysis of 1 [1]. These ratios vary from 0.038 in 90% ethanol to 4.35 in 70% HFIP, a relatively small range considering the large variations in both N T and Y Br values.…”