Definitions Glossary

Term	Definition	Key Context
Primary amine (1°)	Amine with one alkyl/aryl group on N; formula $RNH_{2}$	e.g., methylamine ( $CH_{3}NH_{2}$ ), aniline ( $C_{6}H_{5}NH_{2}$ )
Secondary amine (2°)	Amine with two groups on N; formula $R_{2}NH$	e.g., dimethylamine ( $CH_{3}$ )_{2}NH
Tertiary amine (3°)	Amine with three groups on N; formula $R_{3}N$	e.g., trimethylamine ( $CH_{3}$ )_{3}N
Quaternary ammonium salt	N with four groups, positive charge; formula $R_{4}N^{+}$$X^{-}$	Not a base; cannot donate $H^{+}$
Basicity (Kb)	Equilibrium constant for amine accepting a proton from water	Higher Kb = stronger base
Solvation	Stabilisation of ions by surrounding solvent (water) molecules through H-bonding	Key factor reversing 3° amine basicity in water
+I effect	Inductive electron donation by alkyl groups toward N	Increases electron density on N → increases basicity
Resonance delocalization	Spreading of lone pair or π electrons over multiple atoms via conjugation	Reduces N lone pair availability in aniline
Gabriel phthalimide synthesis	Method using phthalimide + KOH + RX + $N_{2}H_{4}$ to make 1° aliphatic amines	Cannot make $ArNH_{2}$ , 2°, or 3° amines
Hoffmann bromamide degradation	$RCONH_{2}$ + $Br_{2}$ /NaOH → $RNH_{2}$ with loss of one carbon	Product has fewer carbons than starting amide
Carbylamine test	Test for 1° amines: $RNH_{2}$ + $CHCl_{3}$ + 3KOH → RNC (foul smell)	Specific to primary amines only
Hinsberg test	Differentiates 1°/2°/3° amines using $C_{6}H_{5}SO_{2}Cl$ + NaOH	1° soluble, 2° insoluble, 3° no reaction
Diazotization	$ArNH_{2}$ + $NaNO_{2}$ + 2HCl at 0–5 °C → $ArN_{2}^{+}$$Cl^{-}$	Temperature must be ≤5 °C
Sandmeyer reaction	$ArN_{2}^{+}$ + CuX/HX → ArX; uses Cu(I) halide catalyst	Gives ArCl, ArBr, ArCN
Gattermann reaction	$ArN_{2}^{+}$ + Cu powder/HX → ArX; uses metallic Cu	Same products as Sandmeyer but different catalyst
Schiemann (Balz-Schiemann) reaction	$ArN_{2}^{+}$ + $HBF_{4}$ → $ArN_{2}^{+}$$BF_{4}^{-}$ → ArF	ONLY reliable route to aryl fluorides
Azo coupling	$ArN_{2}^{+}$ + phenol/arylamine → azo compound (–N=N–)	Used in azo dye synthesis; alkaline for phenol, weakly acidic for aniline
Azo dye	Coloured compound containing –N=N– chromophore	Largest class of synthetic dyes in industry
Isocyanide (carbylamine)	Compound with R– $N^{+}$ ≡ $C^{-}$ functional group; foul smell	Produced in carbylamine test from 1° amines
Diazonium salt	$ArN_{2}^{+}$$X^{-}$ ; formed from 1° aromatic amines; reactive intermediate	Must be used immediately at low temperature