Search results
Results from the WOW.Com Content Network
Photochlorination is a chlorination reaction that is initiated by light. Usually a C-H bond is converted to a C-Cl bond. Photochlorination is carried out on an industrial scale. The process is exothermic and proceeds as a chain reaction initiated by the homolytic cleavage of molecular chlorine into chlorine radicals by ultraviolet radiation ...
Benzal chloride is produced by the free radical chlorination of toluene, being preceded in the process by benzyl chloride (C 6 H 5 CH 2 Cl) and followed by benzotrichloride (C 6 H 5 CCl 3):
Production capacity of benzotrichloride was estimated at 80,000 tonnes for the year 2000. It is produced by the free radical chlorination of toluene, catalysed by light or radical initiators such as dibenzoyl peroxide. Mono- and di-chlorinated intermediates are observed as benzyl chloride and benzal chloride: [2] C 6 H 5 CH 3 + Cl 2 → C 6 H 5 ...
For example, consider radical bromination of toluene: [5] bromination of toluene with hydrobromic acid and hydrogen peroxide in water. This reaction takes place on water instead of an organic solvent and the bromine is obtained from oxidation of hydrobromic acid with hydrogen peroxide. An incandescent light bulb suffices to radicalize.
The light is absorbed by chlorine molecules, the low energy of this transition being indicated by the yellowish color of the gas. The photon induces homolysis of the Cl-Cl bond, and the resulting chlorine radical converts toluene to the benzyl radical: Cl 2 + hν → 2 Cl· C 6 H 5 CH 3 + Cl· → C 6 H 5 CH 2 · + HCl C 6 H 5 CH 2 · + Cl ...
Benzyl chloride is prepared industrially by the gas-phase photochemical reaction of toluene with chlorine: [3] C 6 H 5 CH 3 + Cl 2 → C 6 H 5 CH 2 Cl + HCl. In this way, approximately 100,000 tonnes are produced annually. The reaction proceeds by the free radical process, involving the intermediacy of free chlorine atoms. [4]
Industrially, the diazonium method is reserved for 3-chlorotoluene. The industrial route to 2- and 4-chlorotoluene entails direct reaction of toluene with chlorine. The more valuable 4-chlorotoluene is separated from 2-chlorotoluene by distillation. Distillation cannot be applied to separating 3-chlorotoluene from 4-chlorotoluene. [2]
"Benzotrichloride can be produced by heating toluene with phosphorus trichloride in the presence of light" though quoted from The Merck Index, this information is not true, or not complete; benzotrichloride (α,α,α-trichlorotoluene, trichloromethylbenzene) is prepared/manufactured by radical chlorination of toluene, in or without presence of phosphorus trichloride, catalysed by light or ...