Photochemical Bromination of Decane, Undecane, and Dodecane in Liquid and Vapor Phases

Abstract

The normal alkanes decane, undecane, and dodecane have been brominated photochemically in both liquid and vapor phases. Partial separation of products has been achieved by column and gas-liquid chromatography and distillation methods. Infrared and nuclear magnetic resonance spectroscopy and mass spectrometry were used to identify the products. The product distributions In the liquid and vapor phases were found to be similar, with a slight preference being Indicated for substitution at the 2 position.

Investigation of the Bromination/Dehydrobromination of Long Chain Alkanes

“…They also studied the bromination of decane, undecane, and dodecane with molecular bromine and showed that the product was mixtures of monobromides with traces of dibromides. 31 Gas and liquid phase bromination gave similar product distributions, and bromination at the primary carbons was not observed. In addition, the bromoalkanes produced were decomposed in the following separation process, i.e.…”

“…Low temperature C–H bond activation has been accomplished using a number of different mediators, including superacids, organometallic catalysts, and halogens. − Unlike oxygen, the use of halogens as oxidants offers a unique means of performing partial oxidation of the carbon in alkanes to produce important chemical intermediates without producing carbon dioxide as a byproduct. Among halogens, bromine is an attractive oxidant in terms of both reactivity and handling.…”

“…The organobromine compounds produced are versatile intermediates and precursors to carbocations, carbanions, carbon radicals and organometallic species. − Bromination can take place either in the vapor phase or in the liquid phase . However, the bromination rate in the liquid phase is usually slower than in the vapor phase .…”

“…Ijam et al studied the temperature (40–120 °C) and irradiation effects on the bromination of a kerosene fraction (boiling point range 170–220 °C) and found that the reaction was most efficient at 85 °C in the presence of UV light of 350 nm. They also studied the bromination of decane, undecane, and dodecane with molecular bromine and showed that the product was mixtures of monobromides with traces of dibromides . Gas and liquid phase bromination gave similar product distributions, and bromination at the primary carbons was not observed.…”

“…13−16 Bromination can take place either in the vapor phase or in the liquid phase. 11 However, the bromination rate in the liquid phase is usually slower than in the vapor phase. 17 As a consequence, catalysts such as metallic chlorides and iodine are commonly employed for accelerating the rate of reaction.…”