What is the relationship between structure and Rf value?
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Rf stands for the retention factor in chromatography. It is a measure of how strongly the substituents are attached (adsorp) to the stationary phase. The stronger the adsorption, the lower is the Rf value.
By the way, Rf can be calculated by dividing the distance covered by the substituent with distance covered by the mobile phase.
A bulky structure ( branched isomer) has a weaker bond compared to a straight chained isomer. This is because the area of contact betweeen molecules is less compared to the straight chained isomer. ( van der Waal forces) Hence it moves faster and have a higher Rf value
By the way, Rf can be calculated by dividing the distance covered by the substituent with distance covered by the mobile phase.
A bulky structure ( branched isomer) has a weaker bond compared to a straight chained isomer. This is because the area of contact betweeen molecules is less compared to the straight chained isomer. ( van der Waal forces) Hence it moves faster and have a higher Rf value
If the substituent can form hydrogen bond with the stationary phase, then its Rf value will be lower as the strong hydrogen bond will cause the substituent to move at a slower pace along the stationary column.
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