(99e) Novel Methods to Separate Azeotropic Butanol-Water Mixtures without the Need for Extractive Distillation or Pervaporative Membrane Separation

Conventional methods to separate azeotropic mixtures containing isomers of butanol i.e., 2-butanol and tert-butanol, require either multi-column extractive distillation or an integrated pervaporation membrane-distillation configuration to effectively break the azeotropes. While the azeotropic mixture of 2-butanol – water is easy to separate as the aqueous and organic phase compositions lie on the opposite side of the azeotrope, the presence of tert-butanol in the mixture makes the separation complicated as its aqueous and organic phase compositions lie on the same side of the azeotrope, making it difficult to cross the distillation boundary to achieve the required separation.

 In this work, various process configurations to effectively bring the mixed butanol product containing 2-butanol and tert-butanol on-specification in-terms of water content were developed without the need for above mentioned cost-intense conventional separation schemes. An optimized separation scheme along with the hydration process was then scaled- up to a 60 kg/day integrated pilot plant and successfully demonstrated the production of on-spec product.