Question

Consider the structures of glycerol trioleate (triolein) and oleic acid methyl ester. Relate how the structural differences might influence physical properties such as melting points, boiling points, and viscosities. Explain how each of these three physical properties might affect the performance of these two compounds as diesel fuels.

Answer 1

Solution.

The  structures of triolein and oleic acid methyl ester are given below:

The melting point of triolein is -4 °C;

The melting point of oleic acid methyl ester is -19.9 °C.

Therefore, triolein has the stronger intermolecular interactions, higher boiling point, and higher viscosity than the oleic acid methyl ester.

The boiling point is related to a diesel fuel volatility (lower b.p. corresponds to a higher volatility). Fuel viscosity should allow the fuel to flow easily, the additions with significant viscosity can cause the engine to damage. The melting point is related to the cold weather characteristics of the fuel.