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The reaction of NO with several alkenes with electron-releasing functional groups were investigated by product analysis and EPR spectroscopy, in the presence and absence of oxygen.

4.2.1.1. n-Butylvinyl ether.

The reaction of n-butylvinyl ether was investigated solely at room temperature. A solution of the enol ether in t-butylbenzene (PhBu^) was degassed using N2, and NO was then bubbled through the system. The reaction vessel was left for a period of 16 hours, after which time the solvent was removed under reduced pressure. A yellow oil was obtained from the reaction. Samples of this oil were sent for analysis by iH NMR spectroscopy and GC-MS. The 200MHz NMR spectrum of the sample showed starting material, and that the extent of reaction was small. The GC-MS chromatogram revealed peaks for solvent, starting material, and a major product, having m/z 160 as its ion of highest mass. However, this was probably a fragment of a larger molecule, thought to be 1,l'-[ethylidenebis(oxy)]bisbutane

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A different major product was also observed that did have M+ 160. This had a different mass spectrum than that reported above, but still possessed the n-butyl fragment. Another major component was identified as dioctyl phthalate. This material

is used as a plasticiser in tubing and was probably transported to the reaction vessel in the gas flow.

A second set of experiments was carried out using cyclohexane as solvent, as this was easier to remove from the reaction upon completion than PhBuL This solution was also degassed and NO bubbled through. After 2 hours, a sample was

removed and analysed by GC-MS and NMR spectroscopy. After this time, it was

noticed that there were brown fumes in the reaction vessel, indicating that there was NO2 present in the system. The reaction was allowed to proceed and was terminated after a 72 hour contact period. A sample was then sent for GC-MS analysis. NMR of the previous sample, (taken after 2 hours), revealed a mixture of peaks, including those displaying aromatic coupling, and a number of side bands. From these it was only possible to tell that some reaction had occurred. GC-MS of the initial sample revealed starting material and solvent, but again, certain products were identifiable. One of these was the 1, l'-[ethylidenebis(oxy)]bisbutane, and the product with M+ 160 was also present. Also observed was l,l'-bicyclohexyl, presumably formed from abstraction of a hydrogen atom from the solvent and subsequent combination with a like radical. The plasticiser was also identified. The next sample also revealed the above products, which were significantly stronger on the

chromatogram. Another major product shown was butan-l-ol. Minor products were

observed and identified from their mass spectra as butyl acetate, butyl formate, 2-

nitrobutane, a compound of possible empirical formula CçHigOa, two of

C9H20O2. The two potentially isomeric compounds came off the column at different

times and both contained the n-butyl fragment. These three final compounds were not positively identified.

A third set of experiments was carried out in a similar manner. The solution was left to react with NO over a period of 48 hours. No NO2 was observed in the system. The solvent, (cyclohexane), was removed under reduced pressure and the

yellow residue analysed by GC-MS and NMR spectroscopy. The latter gave a

no aromatic peaks were observed. No structural information was gleaned from this data. GC-MS analysis again showed many products, all of which were named above.

The fourth set of experiments using NO2 was carried out by way of

comparison. Nitrogen dioxide was bubbled through a non-degassed solution of the enol ether in cyclohexane. The solution was left in contact with the gas for 10 hours. Analysis of the samples removed was by GC-MS, and ^^C NMR spectroscopy.

Preliminary 200MHz NMR spectra were similar to the aforementioned, also without

arom atic signals. G C-M S show ed few er p ro ducts, only 1,1'-

[ethylidenebis(oxy)]bisbutane and the phthalate plasticiser. In an attempt to obtain a superior yield, this experiment was repeated. Analysis of the resulting residue was by GC-MS and 300MHz and NMR. spectroscopy. In this experiment there was suckback of the NO2 produced which resulted in some of the reaction mixture entering the bubbler containing the drying agent, H2SO4. The cyclohexane layer that was formed was removed and the solvent removed. This was taken as the first sample. The second sample was taken from the solution remaining in the reaction vessel. Infra red analysis of the reaction mixtures revealed, for the sample retrieved from the acid

bubbler, C-H (2900cm‘l), C =0 (1650 cm 'l), and possibly C-O (1252cm’l). For the

sample in solution, IR analysis showed O-H (3400cm-1), C-H (2900cm-^). No C = 0

was observed. 300MHz ^H NMR spectroscopy revealed that the phthalate plasticiser was in the cyclohexane (acidified) layer. The remaining solution gave peaks identified as CH3CHO, remnants of the plasticiser, and l,l'-[ethylidenebis(oxy)]bisbutane. There was also a possibility that butanol was present, which would account for the O-H stretch in the IR spectrum. A summary of the products identified by GC-MS analysis is shown: