Saturate fractions from Kuwait crude

C NMR of saturate fractions from Kuwait crude oil (total saturated, n-paraffin, nonnormal paraffins)... 

Figure 2a shows the 13C NMR spectra of the following fractions of Kuwait crude total saturates, normal paraffins, and nonnormal paraffins. Figure 2b shows the corresponding spectra of isoparaffins and cycloparaffins. These fractions have been obtained from the scheme outlined in Figure 1. The spectra demonstrate the need for such detailed separation schemes, for the spectra of the total saturates are too detailed to allow any significant conclusions as to contributions from the various molecular types present.

Separation and Sub-fractionation of Alkanes Saturated hydrocarbons were separated from the neutral oil by silica-gel (60-120 mesh, dehydrated at 150°C for 5 h) chromatography in a 1 m X 30 mm i.d. column eluted with distilled n-hexane. n-Alkanes were separated from iso-octane solutions of total alkanes by adsorption for one week on 5 X molecular sieve (freshly dehydrated for 2h h at U00°C). Washing with iso-octane, followed by Soxhlet extraction, freed the molecular sieve from inwanted non-adsorbed compo mds n-alkanes were recovered by desorption after refluxing the molecular sieve for several hours with n-hexane. For the Kuwait crude and fluidized-bed tar, the molecular-sieve treatment was preceded by urea-adduction of n-alkanes and thiourea-adduction of branched-chain alkanes. 

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