Aldehydes, Ketones, and Carboxylic Acids

Vocabulary and key reaction flashcards covering the physical properties, preparation methods, and chemical reactions of aldehydes, ketones, and carboxylic acids based on the lecture transcript.

Boiling points of Aldehydes and Ketones

These are higher than hydrocarbons and ethers of comparable molecular masses.

Reactivity of Aldehydes vs Ketones

Aldehydes are more reactive than ketones toward nucleophilic addition reactions due to steric and electronic reasons.

Stephen reaction

A method to prepare aldehydes from nitriles and esters using $SnCl_{2} + HCl$ followed by hydrolysis.

Etard reaction

A preparation of aldehydes from hydrocarbons (such as toluene) using chromyl chloride ($CrO_{2}Cl_{2}$) in $CS_{2}$ followed by hydrolysis.

Gatterman-Koch reaction

Synthesizes benzaldehyde from benzene or substituted benzenes using $CO$ and $HCl$ in the presence of anhydrous $AlCl_{3}$.

Clemmensen Reduction

The reduction of a carbonyl group ($C=O$) to a methylene group ($CH_{2}$) using zinc amalgam ($Zn-Hg$) and hydrochloric acid ($HCl$).

Wolf-Kishner Reduction

The reduction of $C=O$ to $CH_{2}$ by reacting with hydrazine ($NH_{2}NH_{2}$) and heating with $KOH/\text{Ethylene glycol}$.

Tollen's test

A test for aldehydes using ammoniacal silver nitrate ($[Ag(NH_{3})_{2}]^{+}$) that produces a silver mirror ($2Ag$).

Fehling s test

A test for aldehydes using $Cu^{2+}$ ions that results in the formation of a red brown ppt ($Cu_{2}O$).

Haloform reaction

Reaction of methyl ketones ($R-C-CH_{3}$) with sodium hypohalite ($NaOX$) to produce a carboxylic acid salt ($R-COONa$) and haloform ($CHX_{3}$).

Cannizzaro reaction

The reaction of aldehydes without $\alpha$-hydrogen (e.g., $2HCHO$) with concentrated $KOH$ to form an alcohol ($CH_{3}OH$) and a salt of carboxylic acid ($HCOOK$).

Structure of Carbonyl group

The carbonyl carbon is $sp^{2}$ hybridized and forms three $\sigma$ bonds in a trigonal planar geometry with bond angles of approximately $120^{\circ}$.

Boiling points of Carboxylic Acids

Higher than aldehydes, ketones, or even alcohols of comparable molecular mass.

HVZ reaction (Hell-Volhard-Zelinsky)

The reaction of carboxylic acids with halogens ($X_{2}$) and red phosphorus ($Red\,P$) followed by water to form $\alpha$-halo carboxylic acids ($R-CH(X)-COOH$).

Methanoic acid uses

Utilized in the rubber, textile, dyeing, and leather industries.

Decarboxylation

The process of heating carboxylic acid sodium salts ($RCOONa$) with soda lime ($NaOH \& CaO$) to produce hydrocarbons ($R-H$).

Carboxyl Group structure

Contains resonance structures where the carbon atom is less electrophilic than the carbonyl carbon in aldehydes and ketones.