Organic Chemistry II - Fats and Oils

Vocabulary practice flashcards reviewing key terms, definitions, reaction types, and analytical constants for fats and oils in Organic Chemistry II.

Triglycerides (Fats & Oils)

Simple lipids that are triesters formed from fatty acids and glycerol, which are generally insoluble in water but soluble in organic solvents.

Fatty Acids

Long-chain hydrocarbons containing a carboxylic acid group ($-\text{COOH}$) at the end of the chain.

Saturated Fatty Acids

Fatty acids that contain no double bonds in their hydrocarbon chain, such as Lauric Acid and Palmitic Acid.

Unsaturated Fatty Acids

Fatty acids containing one or more carbon-carbon double bonds in their hydrocarbon chain, such as Oleic Acid.

Glycerol

A type of alcohol with the IUPAC name Propane-1,2,3-triol that combines with fatty acids to yield fats and oils.

Simple Fat/Oil

A triglyceride formed when glycerol combines with three identical fatty acids, such as Tributyrin.

Mixed Fat/Oil

A triglyceride formed when glycerol combines with three different fatty acids, such as Dioleopalmitin.

Fats vs. Oils Comparison

Fats are solid or semi-solid animal-derived triglycerides rich in saturated fatty acids with melting points $>20\,^\circ\text{C}$, whereas oils are liquid plant-derived triglycerides rich in unsaturated fatty acids with melting points $<20\,^\circ\text{C}$.

Hydrolysis (of Fats & Oils)

The reaction involving the breakdown of triglycerides into glycerol and fatty acids through the addition of water, catalyzed in the human digestive tract by the enzyme Lipase.

Saponification

A hydrolysis process (also known as soap formation) where fats and oils are reacted in the presence of a strong base like $\text{NaOH}$ or $\text{KOH}$ to produce glycerol and soap (salt of fatty acids).

Hydrogenation

The process of converting unsaturated triglycerides into saturated ones by adding hydrogen in the presence of a nickel ($\text{Ni}$) metal catalyst, used to convert oils into fats.

Hydrogenolysis

Hydrogenation involving cleavage that breaks down fats and oils into glycerol and long-chain primary alcohols using hydrogen at high temperature in the presence of a copper chromite catalyst ($\text{CuCr}_2\text{O}_4$).

Rancidification

The phenomenon in which fats and oils develop an unpleasant odor and sour taste when exposed to heat, light, air, or moisture, caused primarily by oxidation of carbon-carbon double bonds or hydrolysis.

Drying Oils

Highly unsaturated oils that undergo oxidation and polymerization when exposed to air to form a thin waterproof film, such as Linseed Oil (rich in linolenic acid).

Acid Value

The number of milligrams of $\text{KOH}$ required to completely neutralize free fatty acids present in $1\,\text{g}$ of fat or oil, calculated as $\text{Acid Value} = \frac{V_{\text{NaOH}} \times N \times 56.1}{W}$.

Saponification Value

The number of milligrams of $\text{KOH}$ required to convert $1\,\text{g}$ of fat or oil into soap, calculated as $\text{Saponification Value} = \frac{28.5 \times (B_{\text{HCl}} - A_{\text{HCl}})}{W}$; higher values indicate shorter acid chain length and lower molecular weight.

Ester Value

The number of milligrams of $\text{KOH}$ required to saponify the esters present in $1\,\text{g}$ of fat or oil, calculated as $\text{Ester Value} = \text{Saponification Value} - \text{Acid Value}$.

Iodine Value

The number of grams of iodine absorbed by $100\,\text{g}$ of fat or oil, measuring the degree of unsaturation using the Wijs Method with formula $\text{Iodine Value} = \frac{(B - S) \times N \times 12.69}{W}$.

Acetyl Value

The number of milligrams of $\text{KOH}$ required to neutralize the acetic acid produced when $1\,\text{g}$ of fat or oil is acetylated with acetic anhydride, calculated as $\text{Acetyl Value} = \frac{1335(b - a)}{1335 - a}$.

Reichert-Meissl (RM) Value

The number of milliliters of $0.1\,\text{N KOH}$ required to neutralize the soluble, volatile fatty acids derived from $5\,\text{g}$ of fat or oil, used to test butter purity (which has an RM value of $25$ to $30$).