Assessment of extraction options for a next‐generation biofuel: Recovery of bio‐isobutanol from aqueous solutions

Abstract

Isobutanol is a widely used platform compound and a raw material for synthesizing many high value‐added compounds. It also has excellent fuel properties and is an ideal gasoline additive or substitute with a very broad development space. Isobutanol production by biological fermentation has the advantages of a comprehensive source of raw materials, low cost, environmental protection, and sustainability. However, it also has disadvantages such as many impurities, low isobutanol concentration, and difficulty separating the water + isobutanol azeotrope. Thus, it is necessary to explore an appropriate downstream separation process for the water + isobutanol azeotrope. K2CO3 with a strong salting‐out effect was used as the salting‐out agent, and the salting‐out of isobutanol from aqueous solutions was investigated at 298.15 K. The effect of the initial salt concentration in the aqueous solution, the recovery of isobutanol, and the effect of dehydration were investigated in detail. The e‐NRTL‐RK model was employed to generate the binary parameters for isobutanol and water, and electrolyte pair parameters for water/isobutanol and ions to reproduce the phase diagram with high accuracy. The processes of solvent extractive distillation, and salting‐out + distillation were simulated by Aspen Plus. The energy consumptions for the solvent‐based and salting‐out‐based processes were compared. The salting‐out + distillation process turned out to be more energy‐saving than the solvent extraction process.

Microextraction with smartphone detection of thiocyanate in saliva of tobacco smokers using paper‐based analytical method

“…This is especially important since the reaction takes place in a basic medium and a higher pH level encourages the development of a red dye [47]. This selection matches what were previously published reports, which have also concluded that potassium carbonate (K 2 CO 3 ) is the optimal salt for separating isobutanol from water using the salting‐out extraction method [48, 49]. The grams of K 2 CO 3 salt added and the corresponding absorbance signals obtained after extraction are shown in Figure S4B.…”

Zeolites in Adsorption Processes: State of the Art and Future Prospects

“…Renewable isobutanol (bioisobutanol) can be produced via fermentative and nonfermentative methods, which have been developed only recently. ,− Isobutanol is a very important platform molecule that can be used as a starting material in the production of olefins (butenes) and aromatics first and polymers and gasoline additives (MTBE) finally . The recovery of bioisobutanol from the aqueous phase is currently done by gas stripping and solvent extraction , or by flash evaporation, followed by condensation and distillation. , but alternative methods, such as extractive distillation using K 2 CO 3 and adsorption, have been proposed. In the case of adsorption, a pure silica Beta zeolite has been used for the vapor-phase recovery of isobutanol from its mixtures with ethanol and water, achieving high selectivities and promising separation performance …”

Techno-Economic Analysis of Upgrading Corn Stover-Based Acetone, n-Butanol, and Ethanol to Higher Ketones and Alcohols: Fuels or Fine Chemicals?

“…Half of the distillate is water, and the rest consists mainly of three solvents, namely, n -butanol, acetone, and ethanol. Our previous study found that the introduction of K 2 CO 3 , K 2 HPO 4 , KH 2 PO 4 , K 3 PO 4 , and K 4 P 2 O 7 into the concentrated or dilute ABE fermentation broth resulted in the separation of ABE molecules from an aqueous solution and the formation of biphase. − Salting-out effects of these inorganic electrolytes are the main driving force for the novel liquid–liquid extraction of biobutanol. , When these inorganic electrolytes dissolve in the ABE aqueous solution, electrostatic hydration of ions and water molecules reduces the solubility of nonelectrolytes by reducing the number of water molecules available as “free” solvents. Therefore, ABE was repelled into the top phase, whereas water was attracted into the bottom phase, resulting in the removal of water.…”

“…29−35 Salting-out effects of these inorganic electrolytes are the main driving force for the novel liquid− liquid extraction of biobutanol. 36,37 When these inorganic electrolytes dissolve in the ABE aqueous solution, electrostatic hydration of ions and water molecules reduces the solubility of nonelectrolytes by reducing the number of water molecules available as "free" solvents. Therefore, ABE was repelled into the top phase, whereas water was attracted into the bottom phase, resulting in the removal of water.…”