Investigation into the Decomposition Pathways of an Acetal-Based Plasticizer

• Published in: ACS omega 2022-08, Vol.7 (34), p.30275-30280
• Main Authors: Freye, Chris E., Snyder, Christopher J.
• Format: Article
• Language: English
• ISSN: 2470-1343; 2470-1343
• DOI: 10.1021/acsomega.2c03494

Until now, it has been assumed that the primary decomposition pathway for the liquid plasticizer bis­(2,2-dinitropropyl)­acetal and bis­(2,2-dinitropropyl)­formal (BDNPA/F) was nitrous acid elimination (NAE). An ultrahigh-performance liquid chromatography (UHPLC) coupled to quadrupole time-of-flight mass spectrometry (QTOF) methodology was developed to discover and identify the degradation products of BDNPA/F. No evidence of NAE was found. However, two other degradation pathways were found: (1) hydrolysis of the acetal/formal functional group and (2) radical-based homolysis of the C–N bond, followed by hydrogen atom abstraction. Hydrolysis of BDNPA/F proceeds by the formation of 2,2-dinitropropanol (DNPOH) and 2,2-dinitropropyl hemiacetal/hemiformal, which further decompose into DNPOH and ethanal/methanal, respectively. Hydrolysis is the dominant decomposition pathway in all samples; however, at higher temperatures, C–N homolysis becomes more significant. Also, the solid PBX 9501 has different ratios of decomposition products than the liquid BDNPA/F due to the slower rate of diffusion through solids than liquids.