JOURNAL OF CHEMICAL EDUCATION
A NEW REAGENT FOR DETECTION OF FERROCYANIDE ION MIEN CHAO1 and MEAN-TSENG SU National Peking University, Peiping, China
IN
addition to the usual test for ferrocyanide ion by 0.1 M Potassium Salts: NOS-, CIOI-. M P o t & n n Salts: Fe(CN)e-8, Fe(CN)s-4, using uranyl acetate, ferric chloride (2), and titanium 0.2 1 M Potasnum Sslt: Cr.0,-. Cr0.-. tetrachloride (a), a good number of organic reagents 0.1 M Ammonium Salt: -CNShas been proposed (3-10). Recently Blank (1) sugTests. All the test solutions of the specified concengested the alcoholic solution of quinone chloroimide for tration give negative tests with the reagent in the methe detection of ferrocyanide ion. This reagent has, (1) neutral solution, (2) glacial acetic acid, @) 8 dia: however, the drawback of becoming darkened on standing, and hence should be freshly prepared immediately M HCI, (4) 8 M NaOH. Ferrocyanide ion gives positive test in media: (1) neutral solution, (2) glacial prior to its use. The writers propose hereby alcoholic solution of acetic acid, and gives negative test in media: (3) 8 M N-chlorosuccinimide as a new organic reagent for the KC1 and (4) 8 M NaOH. Proposed Procedure. Prepare a 0.5 per cent solution detection of ferrocyanide ion. This reagent gives with of N-chlorosuccinimide in 95 per cent ethyl alcohol. ferrocyanide ion in neutral or slightly acidic medium, Place 0.05 rnl. of the neutral or slightly acid solution colorless crystals which are prisms when observed under a low power microscope. Under thepresent experimental under test in a depression of a black porcelain spot test conditions, this reaction may be considered relatively plate. Add one drop of the 0.5 per cent alcoholic Ncharacteristic in comparison with most of its analogs chlorosuccinimide solution. In the presence of ferroreported in the literature, because no interference has cyanide ion colorless, thin, prismatic crystals will be been found from: (I) nitrogen-containing ions (CN-, observed immediately. When carried out in this SCN-, and Fe(CN)s-3); (2) strong oxidizing agents manner the test will detect 8 7 of potassium ferro(GO4-, CmO,=, AsO~-~,CIOJ-); and (3) other oxy- cyanide. ions (No%-, NOa-, Son-, SOa=, &Oa=, &On-, POa-', LITERATURE CITED C03-, Cz04-, Bop-, C4H40d,CZ%OZ-)and S-. (1) BLANK, E. W., J. CHEM.EDUC., 19,321 (1942). (2) FEIOL,F., "Qualitative Analysis by Spot Tests," translated
Preparation of N-chlorosucn'nimide. Succinimide was prepared by the action of succinic acid on urea according to the procedure given by Ma and Sah (6).To prepare N-Chlorosuccinimide the procedure of Tscherniac (11) was followed with slight modification as described below. Two and five-tenths grams of succinirnide was dissolved in 8 cc. of slightly basic distilled water. The solution was kept in an ice bath and chlorine gas was passed into it. Crude N-chlorosuccinimide was obtained as a white precipitate. The product was purified from a large amount of carbon tetrachloride. The pure product, in the form of brilliant, shining plates, melted at 150°C. Preparation of Test Solutions.
1 Present address is Department of Chemistry, Duquesne University, Pittsburgh, Pennsylvania.
by Matthewa, Nordemsnn Publishing Company, Inc., New York City, 1937, p. 176. (3) HYNES,W. A,, AND L. K. YANOWKI,Mikwchemie ver. Mikrochzm. Acta., 29, 265 (1941); Chem. Zmt?. I , 3022
