INTEGRATED PROCESS FOR PREPARING TRIOXANE FROM FORMALDEHYDE

摘要

The invention relates to an integrated process for preparing trioxane from formaldehyde, comprising the steps of: a) a stream A 1 comprising water and formaldehyde and a recycle stream B 2 consisting substantially of water and formaldehyde are fed to a trioxane synthesis reactor and allowed to react to obtain a product stream A 2 comprising trioxane, water and formaldehyde; b) stream A 2 is fed to a first low-pressure distillation column and distilled at a pressure of from 0.1 to 2.5 bar to obtain a stream B 1 enriched in trioxane and additionally comprising water and formaldehyde, and the recycle stream B 2 consisting substantially of formaldehyde and water; c) stream B 1 and a recycle stream D 1 comprising trioxane, water and formaldehyde are fed to a second low-pressure distillation column and distilled at a pressure of from 0.1 to 2.5 bar to obtain a stream C 1 comprising predominantly trioxane and additionally formaldehyde and water, and a stream C 2 consisting substantially of formaldehyde and water; d) stream C 1 is fed to a high-pressure distillation column and distilled at a pressure of from 0.2 to 17.5 bar to obtain the recycle stream D 1 and a product stream D 2 consisting substantially of trioxane, in which a removal of the low boilers present in streams B 1 or C 1 may be undertaken between steps b) and c) or c) and d).