Keyword : chain length, melting point

The melting points of fatty acids generally increase with:-

• increasing chain length
• increasing saturation
• changing of a cis-to a trans-isomer

Thus a short chain saturated fatty acid such as butyric acid will have a lower melting point than long chain saturated fatty acids 
( e.g. palmitic acid ) and even some higher chain length unsaturated fatty acids ( e.g. oleic acid ). This property is reflected when the fatty acids form part of a triglyceride. The more saturated oil or fat may not necessarily have a higher melting point. For example, coconut oil which is about 87% saturated, but contains a high proportion of short chain fatty acids, has a melting range of 24°C – 26°C while palm oil which is about 49% saturated has a melting point in the range of 31°C – 38°C.