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Analysis of ADN, Its Precursor and Possible By‐Products Using Ion Chromatography
Author(s) -
Bunte Gudrun,
Neumann Heinz,
Antes Jürgen,
Krause Horst H.
Publication year - 2002
Publication title -
propellants, explosives, pyrotechnics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.56
H-Index - 65
eISSN - 1521-4087
pISSN - 0721-3115
DOI - 10.1002/1521-4087(200206)27:3<119::aid-prep119>3.0.co;2-t
Subject(s) - chemistry , ammonium , nitrate , elution , ion chromatography , ammonium perchlorate , decomposition , nitrite , ion exchange , ammonium nitrate , ion , chromatography , inorganic chemistry , thermal decomposition , organic chemistry
In the last years ammonium dinitramide (ADN) appeared to be a promising new oxidator and a possible substitute for ammonium nitrate (AN) and especially for the chlorinated oxidizer ammonium perchlorate. Among other main advantages of ADN are to be mentioned the higher energy input combined with a reduced pressure in application. Furthermore, ADN shows no phase transitions like AN. For evaluating the purity of the synthesized and/or treated or aged pure or formulated ADN, the estimated ammonium nitrate content was taken into account. AN is known to be as well a by‐product of the ADN synthesis as a possible decomposition product of ADN. Thermally treated ADN decomposes mainly to N 2 O, H 2 O, NO 2 and AN which further reacts to N 2 O and NH 3 . Determining the nitrate contents assuming the rest being intact ADN must not lead to correct values especially in cases where ADN was treated/handled at higher temperatures in open systems. Concerning the technical scale synthesis of ADN, the precursor ammonium nitrourethane (ANU) must be eliminated in a quick but sufficient way needing a suitable analysis method for detecting nitrourethane besides nitrate and ADN. The objective of this work was to develop a suitable ion chromatographic method for the direct analysis of the anions concerned. Different ion exchanger phases were tested with organic and/or inorganic eluants. The ionic strength and flow rate of the eluant was improved to get an acceptable resolution for nitrite and nitrate combined with a short run time for the whole analysis. Detection was realized by electrical conductivity or UV absorption whereby the measurement wavelengths were optimized in order to get a small signal‐to‐noise ratio and simultaneously a suitable sensitivity especially for NO 3 − and nitrourethane. Under improved conditions (Ion Pac 11, 1 ml/min NaOH, 300 mmol), limits of detection (LOD) of 0.05 to 0.01 ppm were realized for NO 3 − and NO 2 − , respectively, measured at 214 nm. Using 220 nm as detection wavelength resulted in a LOD of about 0.3 ppm for nitrate. Using a wavelength between 210 and 220 nm results in a LOD for ANU of about 1 ppm. The linearity range for the analysis of DN − (285 nm) was found to be very broad (up to 700 ppm). All anions can be analyzed in one run taking maximally 30 minutes.