Oxidation of Cyclohexane with Cobalt (III) Vacuum Pyrolyses.-Samples (0.1 mmol) weighed into Pyrex boats were placed in a horizontal Pyrex pyrolysis tube whose entrance was then sealed off and whose exit led to a U-tube and thence to a vacuum line, the unit being formed from a single piece of glass. The system was pumped out to 10~3 Torr, the U-tube immersed in liquid N2, and the pyrolysis tube heated in an air bath at 250°for 1 hr followed by 30-45 min at 270-280°. The U-tube trap was then sealed off, removed, warmed to 0°, and opened.Reaction of AgNOg-RiNNOg with Carbon Tetrachloride.-Silver nitrate and tetrapentylammonium nitrate were weighed into a 5-ml ampoule and the mixture was protected from atmospheric moisture and heated at 100-110°for 24 hr to produce a homogeneous melt. CCh and any other additives were added to the cooled mixture via a microliter syringe, and the ampoule was sealed, heated under the conditions specified in the tables, chilled, and opened.Identification of dipentylnitrosamine in a typical product was accomplished by triturating with ether and filtering off AgCl, AgNOg, and RgNNOg. Evaporation of the filtrate left a yellow oil whose gc retention time, nmr and mass spectra were those of authentic dipentylnitrosamine. The ir spectrum was that of dipentylnitrosamine plus bands at 3500-2200, 1720, and 945 cm-1 attributable to valeric acid. Gas chromatographic evidence for both valeraldehyde and valeric acid was obtained but irreproducibility prevented quantitation.Pyrolysis of Tripentylammonium Nitrate.-A solution of 1.001 g (4.41 mmol) of tripentylamine in 40 ml of ethanol was treated

The fact that a straight [M]20d vs. S line changes its slope, according to the change in the kind of a Y atom (or radical) which is coplanar with the X atom (or radical) in the same molecule, means that these two atoms (or radicals) (i.e., X and Y) couple with each other to produce a certain partial molecular rotation, in spite of their existence in one plane (cf.

the 18C spectra. W. T. F. thanks the Merck Company Foundation and E. I. du Pont de Nemours and Company and J. B. G. thanks Eli Lilly and Company for financial support.(24) The impurities affect only slightly the chemical shifts in Table II. For example, in the contaminated sample of "CHsCsHiMgCl" the 33-Hz separation between the two Cg peaks at -38°corresponds to a chemical shift difference of only 0.26 ppm between CHaCgHeMgCl and the weighted average of CHsCsHgMgCl and impurity. Since all other peak separations in all the compounds in Table II at low temperature were smaller than 33 Hz, the errors in chemical shifts due to impurities are <0.3 ppm.

Sunz~nary Cobalt (111) ion-catalysed co-oxidation of pcymene and butane affords predominantly p-isopropylbenzoic acid, contrary to the prediction based on the classic a1 free-radical mechanism.

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