Process for the separation of an aqueous mixture of trioxane and formaldehyde and corresponding applications. The aqueous trioxane and formaldehyde mixture has first trioxane:formaldehyde ratio. The process includes the steps of reacting the aqueous mixture of trioxane and formaldehyde with urea, and separation an exiting vapor phase having a second trioxane:formaldehyde ratio that it higher than the first trioxane:formaldehyde ratio. An aqueous mixture of trioxane and formaldehyde coming from a reactor in which trioxane is being synthesized or from a distillation column in which a prior aqueous mixture of trioxane and formaldehyde can be separated from the excess formaldehyde. Raw material for the production of urea-formaldehyde glues or resins can be formed.