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What is the relationship between RONC and ASTM D-86 of light naphtha boiling in the range 40C-120C? what increases its RONC? Does an increase/decrease in IBP increase the RONC or is it the increase/decrease in final boiling point that increases the RONC?
 
Answers
15/04/2010 A: Virendra Kapoor, Petroleum Refining Consultants, vkkapoor9@yahoo.com
Lighter carbon number paraffin has higher ON than that of corresponding heavier paraffin. Aromatics, isoparaffins, olefins enhance ON relative to n-paraffin.n- Heptane has 0 ON whereas n-octane about minus 19
09/04/2010 A: Ralph Ragsdale, Ragsdale Refining Courses, ralph.ragsdale@att.net
It can be either. On the front end, branch chained components (isopentane) have a higher octane than straight chains (n-pentane), and the former has a lower boiling point. On the heavy end, whether or not the benzene is routed to the Isom affects the octane.