Methylene chloride mass spectrum

Specific examples illustrate that similar principles affect the absorption spectra. For example, as we have pointed out above, the neutral form of the C-2 benzyl ester is red in MeOH and orange in methylene chloride. Thus it has the spectrum of the ionized form in the polar, protic solvent and of the nonionized form in the nonpolar solvent methylene chloride [248]. The tributyl ammonium salt of the C-2 octyl ester is soluble in solvents ranging from ethanol-water to toluene. Its spectrum in an essentially nonionizing solvent such as toluene is that of the ionized xanthene [249], The spectrum of the pyrillium salt in ethanol is concentration dependent. In dilute solution the compound is totally ionized and is red, whereas in concentrated solution the compound is not fully ionized and the orange form predominates, as predicted by the law of mass action. 

Because of the complexity of the mass spectrum, it can be used as a fingerprint in identifying a compound. Only methylene chloride has exactly the spectrum shown in Figure 3.8. Thus, by comparing the mass spectrum of an unknown substance with those in a catalog of mass spectra of known compounds, you can determine its identity. The more information you have about the compound, the shorter the search through the catalog of spectra. 

GC/PICIMS spectrum obtained under the following conditions GC conditions—column DB-1 (30 m X 0.320 mm) film thickness 5.00 p,m carrier gas helium at 25 cm/s oven program 45°C for 3 min, then 10°C/min to 300°C for 12 min. injector port 265°C sample 1 p.L at 2000 ixg/p-L solvent methylene chloride samples were injected in the splitless mode (0.75 min load). MS conditions—mass range 50-500 p. electron energy 200 eV ion source temperature 200°C repeller 7.0 V GCMS interface temperature 250°C. 

Parallel results were found when bryostatins 4 and 10 were allowed to react with m-chloroperbenzoic acid in methylene chloride at room temperature. Introduction of one oxygen atom required two days. The SP-SIMS spectra were consistent with an additional 16 mass units, but while epoxidation of bryostatin 4 occurred at the A -olefin, epoxidation of bryostatin 10 occurred at the A -olefin, a conclusion reached by considering the H-NMR spectra. The spectrum of bryostatin 10 epoxide retained the olefinic resonances of the A double bond but the H-30 olefinic resonance at 85.658 was shifted to higher field at 53.358, a shift characteristic of hydrogen on an epoxide. In addition, the C-36 methyl... 

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