The disclosed is about a hydroformylation reaction of a cyclic olefin in
the presence of a rhodium catalyst, and specifically about recovering the
rhodium catalyst. After the cyclic olefin is hydroformylated by the
rhodium catalyst, the product solution is added an extraction liquid
including a cycloalkyl alcohol and separated into two layers. The upper
layer is substantially made up of the rhodium catalyst solution, and the
lower layer is substantially made up of the cycloalkyl aldehyde and the
extraction solution including cycloalkyl alcohol.