... The procedure was repeated and the aqueous filtrates were combined. ... 3. W. Autenrieth and A. Geyer, Ber., 41, 146 (1908) 4. H. Staudinger and H. Freudenberger in Organic Synthesis, AH Blatt, ed., Coil. Vol. 11, John Wiley & Sons, Inc., NY, 1950, pp. 573. ...