Laboratory extractive distillation of molasses-derived ethanol in the context of biosustainability in Indonesia

Molasses-derived ethanol requires dehydration beyond the ethanol-water azeotrope, but laboratory product purity alone cannot establish sustainability. This study examined batch extractive distillation of a 1 L feed containing approximately 70% (v/v) ethanol with 99.8% (v/v) ethylene glycol (EG). Nine reported conditions combined bioethanol-to-EG ratios of 1.00, 5.50, and 10.00 with reflux ratios of 0.50, 2.75, and 5.00; operation was at atmospheric pressure, 78–90 °C, and approximately 3 h. The tabulated ethanol concentrations ranged from 80.327 to 99.949% (v/v). At a reflux ratio of 2.75, the reported concentrations were 99.837–99.932% (v/v). The higher reflux ratio of 5.00 was associated with concentrations larger by 0.017–0.046% points and reported reboiler and condenser energy values larger by approximately 1715 kWh and 1715.62–1716.48 kWh, respectively. This energy association is descriptive because measurement or simulation provenance and normalization basis remain unresolved. Product characterization separately reported at least 99.50% (v/v) ethanol, a density of 0.789 g mL −1 , a viscosity of 1.0 mPa s, and a calorific value of 29.7 MJ kg −1 . Because run-level data, replicate and uncertainty information, the ratio and energy bases, and paired simulation values were unavailable, no validated response-surface optimum or quantitative Aspen Plus agreement is claimed. The evidence supports laboratory feasibility, while biosustainability in Indonesia remains conditional on mass balance, EG recovery, techno-economic analysis, life-cycle assessment, and scale-up validation.