Molecular weight, mass spectral

Molecular weight, mass spectral, n.m.r. and i.r. spectral data indicate structures (80) — (82) for the products. 

Compilations of Reference Spectra There are several compilations of reference mass spectra available of which the oldest is the American Petroleum Institute (Ref 82) collection of spectra obtained mostiy on the older type instruments. Recent collections index spectra variously, eg, under reference number (Ref 19). molecular weight (Refs 12 19), molecular formula (Ref 19), fragment ion values (Ref 19), and base peak (Refs 12 19). A quarterly journal, Archives of Mass Spectral Data ... 

The various spectral and physical properties of the compounds prepared, including their elemental analysis, and IR, NMR, and mass spectra (which contained the appropriate ions, each of the intensity demanded by the isotopic composition of the ion), all fully supported the formulation of the species as reported. With two exceptions, all of the new compounds were found to be colorless liquids, typically having a relatively short liquid range, and they are usually very volatile for their molecular weight. The two exceptions are (CFsliTe, which is yellow-green, and (CFsljTez, which is red-brown (21). 

Tetrachlorodiben2o- >-dioxin. Purified 2,4,5-trichlorophenol (50 grams, 0.26 mole) was converted to its potassium salt and dissolved in 100 ml of bEEE. After addition of the copper catalyst and ethylene diacetate, the mixture was transferred to the bottom of a 300-ml sub-limer with chloroform. Sublimation (200°C/2 mm) yielded 14 grams (39% yield) of 2,3,7,8-tetrachlorodibenzo-p-dioxin. Mass spectral analysis revealed trace quantities of pentachlorodibenzo-p-dioxin, tetrachloro-dibenzofuran, and several unidentified substances of similar molecular weight. The combined impurity peaks were estimated to be <1% of the total integrated GLC area. The product was further purified by recrystallizations from o-dichlorobenzene and anisole. The final product had an estimated 260 ppm of trichlorodibenzo-p-dioxin as the only detected impurity. 

Molecular weight determination by mass spectral analysis... 

The low molecular weight mJz region of spectra derived from microorganism whole cells is generally comprised of mass spectral peaks derived from glycerides, phospholipids, glycolipids, and small protein fragments. This mass spectral information should be examined as a compliment to protein bio-... 

Dienes and polyenes show a pronounced molecular ion in the mass spectra and hence the molecular weight of polyenes can be determined by positive ion mass spectra. The easy removal of a 7r-electron from a diene is usually the reason for the distinct M +. The mass spectral investigation of conjugated polyenes is somewhat similar to that of aromatic structures, due to the high stability of the rearranged ions formed after the... 

The route has the advantage that the anode does not need to be sacrificial, thus avoiding the generation of metal salts. However, the molecular weights of products obtained using this method are as yet very low, and mass spectral data for the oligomeric PMPS indicate a maximum DP of 5. 

Using the atomic weights given in Table 4.2, calculate the mass spectral resolution required to separate the molecular ion of atomic composition C35H48N8O11S from the isotopic peak containing one 13C atom and carry out a similar calculation for the ion of composition C284H432N8407gS7 and its single 13C satellite. 

The results of the interpretation of the gas phase IR and low-resolution mass spectra of 4-phenyl-2-butanone are given in Figure 4. This compound, with a molecular weight of 148, is t3rpical of the size and complexity of compounds which our program handles well. The IR spectrum was taken from the EPA gas-phase IR library, and the mass spectrum from the Registry of Mass Spectral Data.(35)... 

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