Photochemical Studies. XVI. A Further Study of the Chlorination of Benzene

Abstract

The activity coefficients of molecular salicylic acid have been determined in various aqueous salt solutions.For the hydroxybenzoic acids the "salting-out" constants diverge from the values for benzoic acid as one progresses from salts having the highest "salting-out" effects to salts having the lowest effects.A comparison of the "salting-out" constants for ortho, meta and parahydroxybenzoic acids in potassium chloride solutions shows that the constants decrease with the transfer of the hydroxy group to the meta and para positions, respectively.Philadelphia, Pennsylvania

Kinetics and Mechanism of the Gas-Phase Reaction of Cl Atoms with Benzene

“…Photochemical Reactor with Gas Chromatography Analysis at Ford. The 80 cm 3 Pyrex reactor was cylindrical, 20 cm in length, and 2.5 cm in diameter and was irradiated by a single Sylvania F6T5 BLB fluorescent lamp (1.2 cm diameter), positioned 3.3 cm from the center of the reactor. The reactants, containing CD 4 , C 6 H 6 , Cl 2 , and N 2 , were premixed in a separate flask, and the reactor was filled to 120 Torr.…”

“…In 1903 it was established that 1,2,3,4,5,6-hexachlorocyclohexane (HCH) was the final product of the sequence of chlorination reactions initiated by photolysis of Cl 2 in liquid benzene . The first quantitative studies of the gas phase reaction were performed by Noyes and co-workers in the early 1930s , using UV irradiation of C 6 H 6 /Cl 2 mixtures with the course of reaction monitored via changes in total pressure. It was deduced that the reaction of chlorine atoms with benzene proceeds mainly via addition, with chlorination occurring via a short-chain mechanism (chain length of 20−50) giving HCH as the major product and chlorobenzene as a minor product. , In the late 1950s Russell and co-workers − showed that the photochlorination of organic compounds in benzene solvent proceeds via an unusual mechanism in which the active chain carrier is not the free Cl atom but is instead a weakly bound C 6 H 6 −Cl adduct. − The bonding in the C 6 H 6 −Cl adduct reduces its reactivity and increases its selectivity when compared to free Cl atoms. , In the liquid phase, the reaction of Cl atoms with benzene proceeds via addition with a rate constant of k 1 = 1.0 × 10 -11 cm 3 molecule -1 s -1 …”

“…In 1903 it was established that 1,2,3,4,5,6-hexachlorocyclohexane (HCH) was the final product of the sequence of chlorination reactions initiated by photolysis of Cl 2 in liquid benzene. 1 The first quantitative studies of the gas phase reaction were performed by Noyes and co-workers in the early 1930s 2,3 using UV irradiation of C 6 H 6 /Cl 2 mixtures with the course of reaction monitored via changes in total pressure. It was deduced that the reaction of chlorine atoms with benzene proceeds mainly via addition, with chlorination occurring via a short-chain mechanism (chain length of 20-50) giving HCH as the major product and chlorobenzene as a minor product.…”

“…It was deduced that the reaction of chlorine atoms with benzene proceeds mainly via addition, with chlorination occurring via a short-chain mechanism (chain length of 20-50) giving HCH as the major product and chlorobenzene as a minor product. 2,3 In the late 1950s Russell and co-workers [4][5][6][7] showed that the photochlorination of organic compounds in benzene solvent proceeds via an unusual mechanism in which the active chain carrier is not the free Cl atom but is instead a weakly bound C 6 H 6 -Cl adduct. [5][6][7] The bonding in the C 6 H 6 -Cl adduct reduces its reactivity and increases its selectivity when compared to free Cl atoms.…”