Acetonitrile Recovery by Distillation Techniques Combined with Salting‐Out or Sugaring‐Out in Tandem

Abstract

Acetonitrile recovery from a residual aqueous solution was performed by different techniques. Particularly, a residual acetonitrile‐water solution used in high‐performance liquid chromatography analyses at the School of Pharmaceutical Sciences of the University of São Paulo was investigated with the aim to identify the most feasible way to treat such a waste and recover acetonitrile within its dependencies. Three procedures were set up and tested, which consisted of different combinations of well‐known separation techniques, such as fractional distillation, cooling, salting‐out, and sugaring‐out. Cooling followed by distillation and subsequent addition of calcium chloride allowed to recover the highest amount of acetonitrile with a purity greater than 95 %.

Solid–Liquid–Liquid Equilibria of the System Water, Acetonitrile, and Ammonium Bicarbonate in Multiphase Reacting Systems

“…Acetonitrile is a solvent of major importance for research experiments and for the pharmaceutical industry, − but its separation from water cannot be achieved with one distillation unit, given the formation of an azeotrope, so usually a pressure swing , or an extractive distillation ,− technique is used. This passage is necessary when acetonitrile is produced, because water is a byproduct of the consolidate Sohio process, as well as of the oxidative routes sought by many researchers. − All the more important, it is fundamental for the recovery and reuse of acetonitrile from effluents. ,− …”