Fatty Acids
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Fatty Acids

There are a number of carboxylic acids that are referred to as being fatty acids. This list (also shown in Example 8 in your workbook) contains some of the most common of them. We will visit these fatty acids later in the lesson when we deal with fats and oils. But for now I wanted to point out that these fatty acids are carboxylic acids, as you can see from the COOH group at the end of the formulas. Notice that these are, for the most part, long-chained carboxylic acids. For example, myristic acid has fourteen carbon atoms in its carbon chain. Palmitic acid has sixteen and stearic acid has eighteen.
Saturated Fatty Acids
Name No.
of C
Atoms		 Formula
Butyric acid 4 CH3CH2CH2COOH
Caproic acid 6 CH3(CH2)4COOH
Caprylic acid 8 CH3(CH2)6COOH
Capric acid 10 CH3(CH2)8COOH
Lauric acid 12 CH3(CH2)10COOH
Myristic acid 14 CH3(CH2)12COOH
Palmitic acid 16 CH3(CH2)14COOH
Stearic acid 18 CH3(CH2)16COOH

 

Oleic acid not only has a fair number of carbon atoms (18), it also has a double bond. Linoleic acid and linolenic acid also have 18 carbon atoms but have additional double bonds as well.
Unsaturated Fatty Acids
Name No.
of C
Atoms		 Formula
Oleic acid 18 CH3(CH2)7CH=CH(CH2)7COOH
Linoleic acid 18 CH3(CH2)4CH=CHCH2CH=CH(CH2)7COOH
Linolenic acid 18 CH3CH2CH=CHCH2CH=CHCH2CH=CH(CH2)7COOH

The presence of double bonds in a molecule classifies that molecule as being unsaturated because it does not have as many hydrogen atoms as it could. Think of it this way, the carbon atoms are not saturated with hydrogen. Oleic acid is an unsaturated fatty acid. The linoleic and the linolenic acids have more than one double bond, therefore they are called polyunsaturated.

Keep in mind that fatty acids are carboxylic acids which can have very long carbon chains. Fatty acids are synthesized by plants and animals and used in the production of fats and oils. The common names of fatty acids (shown above) are often derived from the Latin or Greek names of the plants, animals or products in which they are found. You might be able to pick out butter, olives, goats (Capricorn).

 

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