Mass spectral evidence for the conversion of benzenephosphonic acid to its cyclic, trimeric anhydride and of benzenephosphonous acid to phenylphosphine

✍ Scribed by Richard H. Wiley

• Publisher: John Wiley and Sons
• Year: 1971
• Tongue: English
• Weight: 642 KB
• Volume: 5
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/oms.1210050606

✦ Synopsis

The mass spectra of benzenephosphonic and benzenephosphonous acids are readily observable under normal operating conditions and, at low sample temperatures (50 to 8S°C), the 70 eV electron-impact degradations are characteristic. The phosphonic acid shows peaks for the molecular ion at 158 amu and for characteristic degradation fragments at 141 (C,H,PO,H), 94 (CGH,O), 78 to 7 (CeHG, CsH5), 65 (H,P02, C5H5), 51 (C,H,), 47 (PO) and 39 (C,H,) amu. Above 120", however, and after a pressure surge indicative of a thermal dehydration in the sample, a peak at 420 amu associated with the cyclic, trimeric anhydride, (C6HsP02)3, is observed along with a charac-