Photo isomerization of <i>cis</i>‐cyclooctene to <i>trans</i>‐cyclooctene: Integration of a micro‐flow reactor and separation by specific adsorption

Abstract

Liquid-phase adsorption has hardly been established in micro-flow, although this constitutes an industrially vital method for product separation. A micro-flow UV-photo isomerization process converts <i>cis</i>-cyclooctene partly into <i>trans</i>-cyclooctene, leaving an isomeric mixture. <i>Trans-</i>cyclooctene adsorption and thus separation was achieved in a fixed-bed micro-flow reactor, packed with AgNO₃/SiO₂ powder, while the <i>cis</i>-isomer stays in the flow. The closed-loop recycling-flow has been presented as systemic approach to enrich the <i>trans</i>-cyclooctene from its <i>cis-</i>isomer. In-flow adsorption in recycling-mode has hardly been reported so that a full theoretical study has been conducted. This insight is used to evaluate three process design options to reach an optimum yield of <i>trans</i>-cyclooctene. These differ firstly in the variation of the individual residence times in the reactor and separator, the additional process option of refreshing the adsorption column under use, and the periodicity of the recycle flow.