A kinetic study of the Friedel-Crafts reaction of naphthalene with para-substituted benzenesulphonyl chlorides; the effect of the substituent

Yoshihiro Yoshii, Akiyoshi Ito, Tsuneaki Hirashima, Seiji Shinkai, Osamu Manabe

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Abstract

The kinetics of the Friedel-Crafts reaction of naphthalene with para-substituted benzenesulphonyl chlorides have been investigated. The rate constants for equations (i) (formation of the sulphonyl cation) and (ii) (sulphone formation) were determined separately. The effect of the para-substituents on k1 was XC6H4SO 2Cl + AlCl3k1k-1 XC 6H4SO2+·AlCl4 - (i) XC6H4SO2+· AlCl4- + C10H8k2 XC6H4SO2C10H7· AlCl3 + HCl (ii) well expressed by the Yukawa-Tsuno equation, log(k1X/k1H) = ρ1[σ + γ1(ΔσR+)] where ρ1 = -2.7 and γ1 = 0.4. On the other hand, the effect of the para-substituents on k3 (= k1k2/k-1) was expressed by the Brown-Okamoto equation, log(k3X/k3H) = ρ3σ+ where ρ3 = -2.8. Thus, the electron-donating para-substituents gave the greater reaction rates. We concluded that the sulphonyl cation gives large negative ρ values as a result of its high reactivity, and that its low selectivity for α-attack is due to a steric effect. These kinetic results have been rationalised in terms of bifunctional acid-base catalysis in phenyl-sulphonylation.

Original languageEnglish
Pages (from-to)777-781
Number of pages5
JournalJournal of the Chemical Society, Perkin Transactions 2
Issue number5
DOIs
Publication statusPublished - Jan 1 1988
Externally publishedYes

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All Science Journal Classification (ASJC) codes

  • Chemistry(all)

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