Mass-spectrometric investigation of hydrocarbons
Summary1. The mass spectra of the diethyl dithioacetals of 2,4:3,5-di-O-benzylidene-D-xylose and 2,4:3,5-di-O-benzylidene-D-ribose have been studied.2. The differences caused by stereochemical factors have been interpreted from the point of view of conformational ideas.
Massenspektrometrische untersuchungen—VII
Zusammenfassung Es wurden die Massenspektren folgender Verbindungen aufgenommen: Methyl-2,3,4-tri-O-methyl-β, d -pyranoside der Ribose, Arabinose, Xylose und Lyxose, Methyl-2,3,4-tri-O-methyl-α, d -lyxopyranosid, Methyl-2,3,5-tri-O-methyl-β, d -arabofuranosid und Methyl-2,3,5-tri-O-methyl-β, d -arabofuranosid-5,5-d 2 . Die Massenspektren ermoglichen eine eindeutige Identifizierung der Stereoisomeren und ihrer Ringgrosse. Der Einfluss von Stereochemie und Ringgrosse kann mit Hilfe der bekannten Fragmentierungsprozesse bei permethylierten Pentosen erklart werden.
Identification of Dihydroxy Aromatic Compounds in a Low-Temperature Pyrolysis Coal Tar by Gas Chromatography−Mass Spectrometry (GC−MS) and Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS)
Dihydroxy aromatics in coal tar undergo rapid coupling reactions with each other and with some coal-derived species during coal pyrolysis and liquefaction. However, only limited information on the structure of dihydroxy aromatics is known. In this study, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and gas chromatography−mass spectrometry (GC−MS) were used to characterize the dihydroxy aromatics in a low-temperature pyrolyzed coal tar and its distillate and residue fractions. Negative-ion electrospray ionization (ESI) FT-ICR MS spectra of coal-tar-derived samples had low molecular masses and narrow mass ranges. Negative-ion ESI is extremely selective for the dihydroxy aromatics present in coal tar. The O2 class species had the highest ion intensity among the species in the negative-ion FT-ICR mass spectrum for each sample. Dihydroxy compounds with an aromatic core structure of benzene, indan, biphenyl (and/or acenaphthene), and naphthalene were identified in the distillate fract...