Engineering topics

Wong, Camille Hing

Publications and source records attributed to Wong, Camille Hing.

6 records

DOE OSTI2022

Aging and Lifetimes Program Annual Report - Part I: Update to BDNPA-BDNPF phase diagram (FY2022)

The eutectic mixture nitroplasticizer (NP) contains water, without exception, on the order of hundreds to thousands of parts per million depending on the exposure conditions. Therefore, to evaluate the properties of NP, one must consider that NP is not simply comprised of two constituents. Here we supplement previous work on the physical properties of NP (Edgar et al., 2020) by expanding on the experimental work therein and addressing inaccuracies detailed in a subsequent comment article (Brown, 2021). Specifically, the purpose of this work is to clarify and modify the phase diagram of the bis(2,2-dinitropropyl) acetal with bis(2,2-dinitropropyl) formal eutectic mixture by considering the effect of water concentrations on the nucleation process.

36 MATERIALS SCIENCE↗

DOE OSTI2022

Identification of 2,2-dinitropropanol, a Hydrolyzed Product of Aged Eutectic Bis(2,2-dinitropropyl) Acetal – Bis(2,2-dinitropropyl) Formal Mixture

Eutectic bis(2,2-dinitropropyl) acetal - bis(2,2-dinitropropyl) formal mixture, nitroplasticizer (herein called NP) has historically been produced by either the ter Meer or oxidative nitration synthesis process, wherein 2,2-dinitropropanol (DNPOH) is produced as an intermediate step in both processes. Therefore that DNPOH, could be present in NP either as a production or hydrolysis degradation product is worth investigation. Here, we synthesized DNPOH, validated the synthesis using NMR, and identified DNPOH in aged NP using liquid chromatography tandem time of flight – quadrupole mass spectrometry (LC-QTOF). Using these results, for the first time we positively identify that DNPOH is absent from NP after its production, but is present as a degradation product through hydrolysis from a thermo-chemical aging profile of NP. To hydrolyze NP, prerequisite is the presence of both water and acid. Despite the presence of water in NP, DNPOH is only generated in the late stage of the aging process, when acid concentration is sufficiently high. It has been previously shown both theoretically and experimentally that a primary step of NP degradation is HONO elimination followed by decomposition, wherein nitric acid, nitrous acid, and water are produced (NP→NP’+2HONO and 2HONO→NO+NO 2 +H 2 O). It is shown from this reaction series that water slows HONO decomposition and therefore in small quantities, 100 s of ppm, water actually stabilizes NP against hydrolysis by equilibrium and reducing acidity.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2021

Liquid Chromatography Mass Spectrometry study of eutectic bis(2,2-dinitropropyl) acetal/formal

This study is the first attempt to document methodology development undergone using liquid chromatography tandem quadrupole time of flight mass spectrometry (LC-QTOF) to investigate degradation products of eutectic bis(2,2-dinitropropyl) acetal/formal nitroplasticizer (called NP here). Method properties investigated are: desolvation temperature (°C) and spray voltage (V) of the electrospray ionization source, and the development of an acetone system rinse to prevent any residual contamination between sample injections. Details are given on why it is essential to investigate method optimization with changes shown in MS/MS analysis in addition to MS results. Trends in MS/MS analytic results reveal important relationships between baseline and aged materials. In addition to verification of previously proposed fragments, insights offered by this newly developed methodology will also identify new degradation products and shed light on the complexity of NP degradation chemistry.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Liquid Chromatography Mass Spectrometry of eutectic bis(2,2-dinitropropyl) acetal/formal: Analyzed Results

This report documents the analysis results produced using liquid chromatography tandem mass spectrometry (LC-MS/MS) to investigate the chemical changes produced by accelerated aging of a eutectic bis(2,2-dinitropropyl) acetal/formal nitroplasticizer (NP). A detailed discussion is given to explain the significance of identified NP degradation ions, which are essential to understand purposed degradation mechanisms. This report is the third of a series on the use of LC-MS/MS to understand the mechanisms of NP degradation.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Liquid Chromatography Mass Spectrometry of eutectic bis(2,2-dinitropropyl) acetal/formal Methodology Development

This report documents the methodology development undergone using a liquid chromatography tandem mass spectrometry (LC-MS/MS) system to investigate the chemical changes produced in the aging process of a eutectic bis( 2,2 - dinitropropyl) acetal/formal nitroplasticizer (NP). Detailed discussion is given to explain why it is essential to develop these methods in LC-MS/MS for analyzing these chemical agents. This report is the second of a series on the use of LC-MS/MS to understand the degradation mechanisms of NP.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Liquid Chromatography Mass Spectrometry Instrumentation and Methodology

This report reviews instrumentation and techniques utilized in liquid chromatography mass spectrometry (LC-MS). The analytical advantages and disadvantages of each major component of different LC-MS systems are discussed, along with a comparison between LC-MS, liquid chromatography tandem mass spectrometry (LC-MS/MS), and gas chromatography mass spectrometry (GC-MS). This report also details future work regarding the use of LC-MS/MS to analyze and identify degradation products from an extensive accelerated aging process of nitroplasticizer (NP). This report is the first of a series on the use of LC-MS to understand the degradation mechanisms of NP.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗