Reactions of aromatic sulphonyl chlorides with anilines

Substitution reactions of 13 para-and meta-substituted anilines with benzenesulfonyl chloride in varying mole fractions of benzene in propan-2-ol have been investigated conductometrically. The second-order rate constants correlate well with pK a values of anilines and with the Hammett's equation. The negative Hammett reaction constant indicates the formation of an electron-deficient transition state. The rate data correlate satisfactorily with macroscopic solvent parameters such as relative permittivity, ε r , and polarity, E T N . Correlation of rate data with Kamlet-Taft solvatochromic parameters (α, β, π *) suggests that both the specific and nonspecific solute-solvent interactions influence the reactivity.

Section: Resultsmentioning

confidence: 99%

Solvent hydrogen bonding and structural effects on nucleophilic substitution reactions: Part 3. Reaction of benzenesulfonyl chloride with anilines in benzene/propan‐2‐ol mixtures

Bhuvaneshwari

Elango

2007

“…When we processed the results taking two significant parameters from the Kamlet-Taft model (a and T*) and two significant parameters from the Koppel-Palm model (Y and E) there is a remarkable improvement in the 'r' value to 0.982 with a n explained variance of 96.4%. The correlation obtained is: (5) log k = -9.467 + 15.653Y -0.098E + 1 . 2 4 1~~ + 1.319~" Addition of the other two parameters B and 'p' improved 'r' values but the correlation is not satisfactory (Refer to the statistical data given in Table 11).…”

Section: (1981)mentioning

confidence: 99%

Effect of solvents and effect of nucleophiles in nucleophilic substitution on benzyl bromide—A kinetic study

Manikyamba¹,

Sundaram

1990

The kinetics of the reaction of benzyl bromide with thiourea was studied in different pure (protic and aprotic) solvents and the rate data was correlated using linear multiple regression analysis. From the regression coefficients which describe the susceptibility of rate to different solvent parameters, information regarding the solvent-reagent, and the solvent-intermediate interactions was obtained and solvation models were proposed.Applicability of the Swain-Scott free energy relationship was tested using different sulphur nucleophiles in acetonitrile solvent and the nucleophilicity constant of N-acetylthiourea was computed as 2.74 from the regression line.

“…Examination of the literature revealed that the effects of structure on S N Ar2 reactions have largely been reported 9–23. However, only very few attempts have been made to study on the effect of solvent on such reactions in a more systematic manner 24–30.…”

Section: Introductionmentioning

confidence: 99%

Solvent hydrogen bonding and structural effects on the reaction of 2‐halo‐5‐nitropyridines with parasubstituted anilines in dimethylsulfoxide/acetonitrile mixtures

Kalaimani¹,

Rathinam²,

Bhuvaneshwari³

2011

Substitution reactions of some parasubstituted anilines with 2-chloro-5-nitropyridine and 2-bromo-5-nitropyridine were carried out conductometrically in dimethylsulfoxide/acetonitrile mixtures. The correlation of second order rate constants with Hammett's substituent constants yields a fairly linear straight line with a negative slope. The correlation of rate data with Kamlet-Taft's solvatochromic parameters is excellent (100R 2 = 97%) in both the substrates. The solvation model proposed is well supported by the solvatochromism exhibited by aniline in the solvent mixture under investigation. The molar extinction coefficient (ε max ) of aniline varies appreciably up to ∼25% with the change in composition of the mixture. The multivariate correlation analysis of ε max (with α, β, π *) suggests that the solvation around NH 2 moiety of aniline through hydrogen bond donor (HBD) property is found to be dominant in the solvation process and consequently in altering the rate. The observation is that the dominance of HBD property in solvation is further confirmed by the cyclic voltammetric oxidation of aniline in the solvent mixture. C