Question

Which has a higher melting point, glyceryl tripalmitoleate or glyceryl tripalmitate?

Short answer

Glyceryl tripalmitate has a higher melting point than glyceryl tripalmitoleate.

Step-by-step solution

Melting point of fatty acids

The difference in the melting point of fatty acids can be explained based on the molecular weight and unsaturation in the fatty acids.The higher molecular weight leads to a higher melting point, and the lesser unsaturation leads to a lower melting point.

Difference in melting point of fatty acids

The difference in melting point based on the molecular weight can be explained only if there is a difference in the chain length. If the chain length is the same, then the difference in melting point can be explained based on unsaturation.

Difference in melting point of the given compounds

Structure of glyceryl tripalmitate

Structure of glyceryl tripalmitoleate

Glyceryl tripalmitate has no double bonds in the chain but glyceryl tripalmitoleate has three double bonds in the hydrocarbon chain. Due to these three double bonds, the chain gets bent leading to lesser intermolecular forces.

Thus, glyceryl tripalmitoleate melts more easily than glyceryl tripalmitate.

Therefore, glyceryl tripalmitate has a higher melting point than glyceryl tripalmitoleate.