Gravimetric determination of zirconium with 1-Naphthylacetic acid

Abstract

Re/erence.s 1. Goller, E. J.: J. Chem. Edueat. 42, 442 (1965). 2. Ishida, K., Kuroda, R.: Japan Analyst 19, 81--86 (1970). 3. Ottendorfer, L. J.: Anal. Chim. Acts 88, 115 (1963). 4. Seiler, H., Seiler, M.: ttelv. Chim. Acta 48, 1939 (1960 1-Naphthylacetic acid has been found to be a selective reagent for the determination of zirconium, similar to phenylacetic acid which has been used for the same purpose earlier [1]. A curdy white, insoluble and easily washable precipitate is obtained within the pH region of 0.1 to 0.45 N HC1. With higher H+ concentrations low results are obtained. As direct weighing is not possible because of certain variations in the composition the precipitate is ignited to oxide. The composition of the Zr-reagent compound has been found to be 1:1. The proposed structural formula is quite similar to that described earlier in the case of phenylacetie acid [1].The presence of 8042-ions does not interfere up to a ratio of ZrO~: S042-= 1 : 3. The following cations are not precipitated: Ca 2+, Ba~'+, SrZ+, Zn~+, Hg2+, Ala+, The+ Mn~+, FEZ+, Co2+, Ni2+, (U02)~+. (Vs04) 2+ * Part VII: diese Z. 210, 335 (1965). and Co s+ are copreeipitated with Zr, yet a double precipitation overcomes this difficulty. The determination is not possible in the presence of Sn ~+, Ti 4+ and Be ~+ because of hydrolysis. 0.12 to 0.002 g of Zr were determined with errors up to -4-0.0004 g. Procedure.The sample containing about 0.01 g of Zr/ml is heated to boiling, then ammonium nitrate is added (5 g per 100 ml) and the normality is adjusted to about 0.3 N I4C1. 20/0 Boiling solution of potassium 1-naphthylaeetie acid is slowly added with constant stirring until complete precipitation. The solution is slowly heated on a water bath for 30 rain and is then filtered through Whatman paper No 42. 1~ Reagent solution is used for washing. The precipitate is dried, ignited and weighed as ZrO~.A~e]ere.nc~ The behaviour of bromocomplexes of the platinum metals in the ultraviolet spectral region has not yet been studied or utilized in analytical chemistry [1].Within the framework of a systematic study of that subject the bromocomplexes of platinum, palladium, rhodium and iridium were investigated within the spectral region from 200 to 350 nm. The results are * Part I: diese Z. 260, 321 (1972).