Question

One of the main triglycerides in palm oil is tripalmitin. It contains three fatty acids with carbon designations of, [16:0]. Draw the structure of tripalmitin. Would you expect this molecule to be a solid or liquid at room temperature?

Accepted Answer

Understand the structure of tripalmitin: Tripalmitin is a triglyceride composed of glycerol and three palmitic acid molecules. Palmitic acid is a saturated fatty acid with the formula $$C_{16}$H_{32}O$$_{2} (carbon designation [16:0], meaning 16 carbons and no double bonds). Draw the glycerol backbone: Glycerol is a three-carbon molecule with hydroxyl groups (-OH) attached to each carbon. Represent this as $$CH_{2}OH-$$CHOH-$$CH_{2}OH. $$Attach the fatty acids: Each hydroxyl group of glycerol reacts with the carboxyl group (-COOH) of palmitic acid to form an ester bond. Replace the -OH groups on glycerol with the palmitic acid chains, resulting in a structure where three palmitic acid chains are esterified to the glycerol backbone. Analyze the physical state: Saturated fatty acids like palmitic acid have straight chains that allow tight packing. This tight packing increases intermolecular forces, such as van der Waals interactions, making tripalmitin likely to be a solid at room temperature. Conclude the reasoning: Since tripalmitin contains only saturated fatty acids ([16:0]), its structure promotes tight packing and higher melting points, which supports the expectation that it is a solid at room temperature.

One of the main triglycerides in palm oil is tripalmitin. It contains three fatty acids with carbon designations of, [16:0]. Draw the structure of tripalmitin. Would you expect this molecule to be a solid or liquid at room temperature?

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Key Concepts

Triglycerides

Fatty Acid Structure

Physical State of Lipids