PATENT

3356.  SMITH, E. F., AND VOORHEES, V.  (Standard Oil Do of Indiana).  Recovery of Organic Acids With an Amine Solution.  United States Patent 2,568,095, Sept. 18,1951; appl. filed Apr. 29, 1949, Serial No. 90288; 10 claims (Cl. 260-450).

Organic acids dissolved in the hydrocarbon solution obtained by hydrogenating CO in the presence of an alkali-promoted Fe catalyst are recovered by treating the solution at a temperature 10°-60° with an aqueous extractant solution containing 5-25 wt. % of a H2O-miscible amine such as triethanolamine.  The resulting miscible amine such as triethanolamine.  The resulting extract is backwashed with a liquid hydrocarbon to remove any organic oxygenated compounds other than organic acids.  The resulting purified aqueous extract is then extracted counter currently at elevated temperature above about 75° with a H₂O immiscible organic acid fraction, whereby the greater portion of the acids are liberated from the amine and are selectively extracted by the H₂O-immiscible organic acid.  The organic extract is fractionally distilled to separate a H₂O-miscible organic acid fraction and a H₂O immiscible organic acid fraction. The depleted amine solution is stripped of residual acids by steam distillation and recycled to step 1 of the process.