The invention is directed to a process to continuously prepare a cyclic carbonate product by reacting an epoxide compound with carbon dioxide in the presence of a supported dimeric aluminium salen complex. The process is performed in a reactor comprising a slurry of the supported dimeric aluminium salen complex and liquid cyclic carbonate product. The produced cyclic carbonate is discharged from the reactor while the supported dimeric aluminium salen complex remains in the reactor. The liquid carbonate product is purified by means of distillation. Between the reactor and the distillation one or more buffer vessels are present having a volume of between 5 and 50 m3 per kmol of dimeric aluminium salen complex as present in the reactor.