No abstract

An integrated reaction−distillation process for the production of methylal from aqueous, methanolic formaldehyde solutions is developed. The process consists of a serial connection of a reactor in which the feed is converted to chemical equilibrium by a heterogeneously catalyzed reaction followed by a pressure-swing distillation sequence, in which a heterogeneously catalyzed reactive section as well as a vapor side draw are used. The catalyst is an acidic ionexchange resin. The process yields methylal in purities over 0.999 g/g; methanol can be recovered in purities over 0.94 g/ g, and water is withdrawn in a purity of 0.99 g/g. The conversion of formaldehyde is above 99.9%. The process development is carried out based on steady-state simulations with a model which explicitly accounts for the oligomerization reactions of formaldehyde in aqueous, methanolic formaldehyde solutions. The model is validated by a comparison to experiments that are carried out in a laboratory glass distillation column.