Aromatic halogenation. IV. Kinetics and mechanism of iodination of phenol and 2'6-dibromophenol

Abstract

arenes are down in the polyarylmethane region and should be amenable to direct equilibrium measurement. Unfortunately, with CsCHA the higher polycyclic benzenoid hydrocarbons rapidly form radical anions such that we have been unable to accomplish such direct measurement.The present pK results may be related to the exchange rates of Ebel and Ritterbusch with lithium W-methylanilide at 150°.23 Their relative deuterium exchange rates for TPM, DPM, and 9-methylphenanthrene give a Brpnsted a of about 0.26 at 150°, a value that corresponds to ~0.37 at 25°if the effect is all in AH*.Hence, this reaction is much like that with LiCHA except that the anilide ion is a weaker base and higher temperatures are required for equivalent reactivities.

Interaction Kinetics of I2(aq) with Substituted Phenols and Humic Substances

“…Grovenstein et al (19) pointed out that an adjustment to the rate coefficient obtained from Figure 2b is necessary to account for changes in the equilibrium between I -(aq) and I3 -(aq) at low concentrations of I -(aq). A simple adjustment has the form and arises because the concentration of I -(aq) imperfectly correlates with the concentration of I3 -(aq) at low total concentrations of I -(aq) (eq 1).…”

123 ( 125 ) Xe-Ex posed KIO3 , a Reagent for lodination with High Specific Activity

“…Kinetic studies in classical iodination by VAlNSHTEINeí al. [12] and by GROVENSTEIN et al [13] revealed that at least the reaction with aniline and phenol proceeds via molecular iodine which forms an intermediate complex with the substrates (eq. 5 and 6).…”

“…5) is the rate determining step at low iodine concentration (3 · 10~7M) whereas at high concentration it is the depro tona tion (eq. 6) of the product [13]. At saturation concentration of the substrate, the iodination is completed in less than one minute after dissolution of the 123 ( 12S )xe-exposed KI0 3 in the substrate solution.…”

Dual Studies on a Hydrogen–Deuterium Exchange of Resorcinol and the Subsequent Kinetic Isotope Effect

“… 14 , 15 The reaction progress is monitored visually via the disappearance of iodine color in the reaction solutions due to the formation of 2-iodoresorcinol and 4-iodoresorcinol. The kinetic isotope effect of the iodination reactions is quantified by analysis of UV–vis spectroscopic data 14 , 15 provided to students.…”