Effect of metal sequestrants on the decomposition of hydroxylammonium nitrate

Hydroxylammonium nitrate (HAN) is an energetic salt used in flight-proven green monopropellants such as ASCENT (formerly AF-M315E) flown in NASA’s 2019 Green Propellant Infusion Mission and SHP163 flown in JAXA’s Rapid Innovative Satellite Technology Demonstration-1. Decomposition of HAN is catalyzed by metals commonly found in storage tanks, a factor limiting its use. This work investigates the ability of metal-sequestering chelating agents to inhibit the de-composition of HAN. Isothermal and dynamic thermogravimetric analysis (TGA) were used to find isothermal decomposition rates, decomposition onset temperatures, and first-order Arrhenius re-action rate parameters. 2,2’-bipyridine (Bipy), triethanolamine (TEA), and ethylenediaminetetraacetic acid (EDTA) were studied as 0.05, 0.1, 0.5, 1, and 5% by weight additives in 90% aqueous HAN by weight. An isothermal decomposition rate of 0.137%/hr at 348 K was observed for HAN. Addition of 1% Bipy and 1% TEA reduced the isothermal decomposition rate by 20.4% to 0.109%/hr and by 3.65% to 0.132%/hr, respectively, showing that Bipy can inhibit decomposition. The addition of 1% EDTA increased the isothermal decomposition rate by 12.4% to 0.154%/hr. Bipy was found to increase the decomposition onset temperature from 454.8 K to 461.8 K while TEA and EDTA returned inconclusive changes. First order reaction rates calculated by the Ozawa-Flynn-Wall method were found to be insufficient to capture the effects of the additives tested. Bipy was found to inhibit the decomposition of HAN, while TEA and EDTA produced little or negative effect, a result believed to be due to poor metal complex stability at low pH and high acidity, respectively. Spectrophotometry was used for colorimetric analysis of Bipy+iron complexes and showed that Bipy forms chelate complexes with trace iron impurities when added to HAN solutions.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Aerospace Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2022

Author dc:creator

• Broemmelsiek, Emil Jonas

Contributors dc:contributor

• Rovey, Joshua L.

• Engineering

Statement dc:rights

• Copyright 2021 Emil Broemmelsiek

Language dc:language

en, eng

Handle dc:identifier

http://hdl.handle.net/2142/113931

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F113931