摘要 |
Processes are disclosed for separating by adsorption lower octane normal and mono-methyl paraffins from hydrocarbon feeds containing normal, mono-methyl and more highly branched paraffin fractions in the pentane and hexane carbon range. Adsorbents capable of adsorbing mono-methyl paraffins but not di-methyl branched paraffins are employed to adsorb normal and mono-methyl branched parafins. Isopentane, although adsorbed along with the mono-methyl hexane paraffins, is preferentially adsorbed and eluted from the adsorber bed and recovered as an adsorption effluent along with di-methyl branched hexane paraffin. In one aspect of the invention adsorbents capable of adsorbing normal paraffins but not mono-methyl paraffins are additionally employed to pretreat the feeds to adsorb normal paraffins. Isomerization processes are disclosed for isomerizing the normal and mono-methyl paraffins to produce higher-octane isopentane and more highly branched paraffins.
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