Production of High-Purity Allyl Alcohol by the Salting-Out Method from Formic Acid-Mediated Deoxydehydration of Glycerol

Abstract

Formic acid-mediated deoxydehydration of glycerol has emerged as an attractive approach to produce allyl alcohol; however, separation of allyl alcohol by distillation is not a straightforward task from the mixture of allyl alcohol, formic acid, and water because of their very close boiling point. A new route to separate allyl alcohol with high purity has been developed by the precipitation, distillation, and salting-out process. Among 11 salts, NaCl, K 2 HPO 4 , and K 2 CO 3 could easily induce the liquid−liquid phase splitting. K 2 CO 3 exhibits the best salting-out effect in a single salt system. Meanwhile, the solubility of allyl alcohol in the organic phase could be predicted by the mass fraction of salt. The allyl alcohol purity of >99.9% could be achieved by using 35% K 2 CO 3 + 25% K 2 HPO 4 . The results also provide valuable references to obtain high-purity allyl alcohol for all the glycerol to allyl alcohol routes, because it is indispensable to separate allyl alcohol from its aqueous solution.

A salting-out strategy for the efficient separation of an azeotropic mixture of allyl alcohol and water

“…The content of allyl alcohol in the salting-out experiment was ascertained through high-performance liquid chromatography (HPLC, Shimadzu, LC-20AD), and analytical methods were performed as described in the literature. 34 The salt ion contents were determined through inductively coupled plasma atomic emission spectrometry (Agilent 725, ICP-AES). The water content was determined through Karl Fischer titration (831 KF coulometer, Metrohm, Switzerland).…”

Transition metal-catalyzed deoxydehydration: missing pieces of the puzzle

“…80 Another strong organic reductant is formic acid (Entry 2), which is used both in catalyzed 12 and uncatalyzed DODH. 81–84 As a variant, trimethylformate 85 or triethylorthoformate has been used. 82…”

“…Jia et al 83 used a combination of precipitation, distillation, and salting out to recover allyl alcohol after reacting glycerol with formic acid in uncatalyzed DODH. The method was developed because of the close boiling points of formic acid, water, and allyl alcohol.…”

“…80 Another strong organic reductant is formic acid (Entry 2), which is used both Catalysis Science & Technology Mini review in catalyzed 12 and uncatalyzed DODH. [81][82][83][84] As a variant, trimethylformate 85 or triethylorthoformate has been used. 82 Primary and secondary alcohols can serve as reductants and will be oxidized to aldehydes and ketones, respectively.…”

“…Alternatively, the authors precipitated benzaldehyde through reversible formation of a bisulfite adduct by addition of aqueous NaHSO 3 to the reaction mixture. Jia et al 83 used a combination of precipitation, distillation, and salting out to recover allyl alcohol after reacting glycerol with formic acid in uncatalyzed DODH. The method was developed because of the close boiling points of formic acid, water, and allyl alcohol.…”