Photoisomerization of cis- to trans-cyclooctene: integration of a
micro-flow reactor & 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
cis-cyclooctene partly into trans-cyclooctene, leaving an isomeric
mixture. Trans-cyclooctene adsorption and thus separation was achieved
in a fixed-bed micro-flow reactor, packed with AgNO3/SiO2 powder, while
the cis-isomer stays in the flow. The closed-loop recycling-flow has
been presented as systemic approach to enrich the trans-cyclooctene from
its cis-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 trans-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.