Recovery of 2-pyrrolidone from dilute alkaline solutions
AssigneeChevron Research Company
InventorByron E. Anshus
Life of this patent
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Abstract
A two-stage evaporative method for recovering polymerizable 2-pyrrolidone from alkaline aqueous solutions such as those obtained by washing the catalyst from an incompletely reacted polypyrrolidone polymerizate, includes the steps of neutralizing the base with mineral acid, removing most of the water in an initial reduced pressure evaporation and recovering the pyrrolidone from a salt/pyrrolidone slurry by vaporization under reduced pressure.
Claims4
A process for the recovery of 2-pyrrolidone from alkaline aqueous solution, which comprises the steps of adding sulfuric acid to said solution in amounts sufficient to provide a neutralized or acidified solution of 3-7 pH, removing by a first evaporation a major amount of the water from said neutralized or acidified solution to provide a slurry comprising sulfate salt and 2-pyrrolidone, and recovering 2-pyrrolidone from said slurry by a second evaporation under reduced pressure.
Dependencies are inferred from the claim text.