Chemical Properties
beige to ochre-yellow powder
Uses
As reagent for alkaloids, tryptophan, phenylalanine, and for the detection and estimation of calcium.
Uses
Reagent for the isolation of amines as crystalline π-complexes.Picrolonic acid is an analytical reagent used for the estimation of calcium, magnesium, lead, strontium and thorium. It is also used for the analysis of alkaloids, tryptophan and phenylalanine.
Uses
With calcium(II), lead(II) and thorium(IV) the reagent gives complexes which
are practically insoluble in water. The high molecular weight crystalline complexes
can be used to advantage for the accurate determination of minute amounts of
various metals.
The reagent has also proved suitable for the spectrophotometric determination
of calcium. Calcium picrolonate is transformed by bromine water in alkaline
medium to a red, water-soluble complex. The absorption of this compound is
constant for about two days and it also follows the Beer-Lambert Law.
Purification Methods
Crystallise picrolic acid from water or EtOH (solubility is 0.123% at 15o and 1.203% at 100o in H2O; and 1.107% at 0o and 11.68% at 81o in EtOH). It forms Ca, Cu Hg, Mg, Na, Sr, Pb and many other metal complexes [Maquestian et al Bull Soc Chim Belg 82 233 1973, Isaki et al. Chem Ber 74 1420 1941]. [Beilstein 24 H 51, 24 I 218, 24 II 25, 22 III/IV 105.]
