Heptenes mass spectra

Doubly charged ions of 1-heptene were observed in its field ionization mass spectrum by Tecon, Stahl and Gaumann267. By using 13C-labeled compounds they were able to prove that these ions are formed in an absorption process on the emitter surface, partly by ion-molecule reactions. 

A vessel was charged with 6-methyl-5-hepten-2-one (1.0 mol) and 516g CH2CI2, cooled to — 19°C, and boron trifluoride etherate (0.5 mol) and ketene gas metered in over the course of 4 hours. Throughout this period the temperature was maintained between — 12°C and — 14°C. Thereafter urotropine (2.5 mmol) was added and the solution stirred for 30 minutes at 0°C. The solvent was evaporated at 15 mbarr at 20 °C and the product isolated in 80.9% yield by vacuum distillation. H-NMR and mass spectrum data supplied. 

Figure 4. Mass spectrum of volatile by-products occurred in the W(CO)6/CCl4, 1-heptene/hv system.

Fig. 5.11. Instrumental analysis of 5-methyl-(E)-2-hepten-4-one (according to Emberger, 1985) (a) mass spectrum, (b) H-NMR spectrum (for discussion, see text)...

Beef, lamb, and pork muscles (m. longissimus dorsi) with attached adipose tissue were purchased from a local retailer. Adipose tissue was separated from muscle, and both were analyzed by SDE. Each sample was minced, and 100 g of either muscle or adipose tissue was placed in a 2-L round-bottomed flask, to which 750 mL of water was added. The samples were then extracted for 2 hr, using 30 mL of pentane/ether (9 1) as solvent. Two drops of silicone antifoaming agent were added to the meat samples. After the first extraction, each sample was extracted a second time, to determine whether any remained in the sample. The extracts were stored in a freezer overnight to remove water and concentrated to 0.2 mL. Methyl decanoate (500 ng) was added as an internal standard. Two replicates were performed for each extraction. A standard of pure (Z)-4-heptenal was also injected to determine its retention time and mass spectrum. 

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