Organic Chemistry: Thiols, Alcohols, Aromatic Compounds, and Carbon Classification

Comprehensive vocabulary flashcards covering thiols, alcohol physical properties and reactions, aromatic compounds, and carbon atom classifications.

Thiol

An organic compound containing a sulfhydryl group ($-SH$) bonded to a tetrahedral carbon atom, known for possessing a distinctive foul odor.

Sulfhydryl Group

The $-SH$ functional group in organic sulfur compounds, composed of a sulfur atom bonded to a hydrogen atom.

3-Methyl-3-sulfanyl-1-hexanol

The specific thiol compound responsible for the characteristic odor of human sweat.

Thiol vs. Alcohol Boiling Points

Thiols have weaker intermolecular forces and significantly lower boiling points than alcohols of similar size (e.g., ethanethiol at $35\,^\circ\text{C}$ vs. ethanol at $78\,^\circ\text{C}$) because sulfur cannot form intermolecular hydrogen bonds.

Disulfide

A compound containing a covalent sulfur–sulfur ($S-S$) bond, commonly produced by the oxidation of two thiols.

Thiol Oxidation

A chemical reaction in which two thiol molecules lose two hydrogen atoms ($2\text{ H}$) to form a disulfide bond ($S-S$).

Disulfide Reduction

A chemical reaction where hydrogen atoms are added across an $S-S$ bond to convert a disulfide back into two distinct thiol ($-SH$) groups.

Alpha-Keratin Disulfide Rearrangement (Perm)

The process of altering hair shape by using a reducing agent to break disulfide ($S-S$) bonds in alpha-keratin to $-SH$ groups, curling the hair, and applying an oxidizing agent to re-form disulfide bonds in new positions.

Alcohol Dehydration

A reaction in which an alcohol loses a molecule of water ($\text{H-OH}$) in the presence of an acid catalyst such as $\text{H}_2\text{SO}_4$ to produce an alkene.

Oxidation (in Organic Chemistry)

A reaction that results in an increase in the number of $C-O$ bonds or a decrease in the number of $C-H$ bonds.

Primary ($1^\circ$) Alcohol Oxidation

A two-stage oxidation process where a primary alcohol is first oxidized to an aldehyde (replacing one $C-H$ bond with a $C-O$ bond), which is then further oxidized to a carboxylic acid (replacing two $C-H$ bonds with two $C-O$ bonds).

Secondary ($2^\circ$) Alcohol Oxidation

An oxidation reaction where a secondary alcohol is converted to a ketone by replacing one $C-H$ bond with a $C-O$ bond; ketones cannot be further oxidized because the carbonyl carbon lacks an attached hydrogen.

Tertiary ($3^\circ$) Alcohol Oxidation Resistance

The chemical property where tertiary alcohols undergo no oxidation reactions because there is no $C-H$ bond on the carbon bearing the $-OH$ group.

Methanol Toxicity

The harmful physiological effect of ingesting methanol, which is metabolized by alcohol dehydrogenase to formaldehyde (methanal) and then by aldehyde dehydrogenase to formic acid, lowering blood pH and causing blindness or death.

Acetaldehyde

A toxic intermediate formed by the hepatic oxidation of ethanol; its accumulation when ethanol is consumed faster than it can be metabolized causes hangover symptoms.

Aromatic Compounds

A class of organic compounds containing a benzene ring, many of which exhibit distinctive aromas.

Benzene

A planar, cyclic hydrocarbon with the formula $\text{C}_6\text{H}_6$ consisting of a six-carbon ring with alternating double bonds and bond angles of $120^\circ$.

Fused Ring Aromatic Hydrocarbons

Polycyclic aromatic compounds containing multiple fused benzene rings, including naphthalene (two fused rings, found in mothballs), anthracene (three rings fused in a row), and phenanthrene (three rings fused angularly).

Loratadine (Claritin)

An antihistamine drug that contains exactly one benzene ring within its multi-ring chemical structure.

Alcohol Geometry and Polarity

The spatial arrangement around the oxygen atom in an alcohol, which has a bent shape with an angle of approximately $109.5^\circ$ due to two single bonds and two lone pairs, resulting in polar $C-O$ and $O-H$ bonds and a net dipole.

Intermolecular Hydrogen Bonding in Alcohols

Strong intermolecular attractions occurring between the partially negative oxygen of one alcohol and the partially positive hydrogen of an $-OH$ group on an adjacent molecule, yielding significantly higher boiling points and melting points than alkanes of similar molar mass.

Water Solubility Threshold of Alcohols

The rule of thumb where alcohols with 5 or fewer carbons are water-soluble due to the dominant polar $-OH$ group, whereas alcohols with more than about 5 carbons are water-insoluble due to the large nonpolar hydrocarbon chain.

Primary ($1^\circ$) Carbon

A carbon atom directly bonded to only 1 other carbon atom.

Secondary ($2^\circ$) Carbon

A carbon atom directly bonded to 2 other carbon atoms.

Tertiary ($3^\circ$) Carbon

A carbon atom directly bonded to 3 other carbon atoms.

Quaternary ($4^\circ$) Carbon

A carbon atom directly bonded to 4 other carbon atoms.