Method and device for the continuous implementation of a photochemical reactions

摘要

In a continuous process for the photonitrosation of cycloalkanes, a concentration gradient in respect of the photo-sensitive substance is produced in the solution to be irradiated, the concentration gradient being such that the concentration of the photosensitive substance in the reaction medium adjacent to the light transmitting surface is at most half the concentration in the rest of the reaction medium. The cycloalkanes may have 5 to 12 carbon atoms, and may be reacted in the temperature range - 30 DEG to + 30 DEG C. with for example nitrosyl chloride in amount to give from 0.3% to 0.5% by weight in the reaction mixture of nitrous oxide and chlorine under the influence of light having a wave-length of 360 to 600 millimicrons, advantageously in the presence of hydrogen chloride. If a solvent is needed it may be benzene, chloroform, ethylene chloride or glacial acetic acid. The example relates to the nitrosation of cyclohexane, in which a solution of nitrosyl chloride in cyclohexane saturated with hydrogen chloride is exposed at 18 DEG to 20 DEG C. to a mercury vapour lamp to give cyclohexanone oxime hydrochloride.