all types of amines are formed. This method is called Sabatier – Mailhe method. C H OH NH .. Al O , - H O C H - NH ..
C H OH -H O C H OH - H O (C H ) N (C H ) NH .. .. b) Phenol reacts with ammonia at C in the presence of anhydrous ZnCl to give aniline NH NH anhy.ZnCl , C Phenol aniline . .
Properties of amines . Physical state and smell The lower aliphatic amines (C -C ) are colourless gases and have ammonia like smell and those with four or more carbons are volatile liquids with fish like smell. Aniline and other arylamines are usually colourless but when exposed to air they become coloured due to oxidation. .
Boiling point Due to the polar nature of primary and secondary amines, can form intermolecular hydrogen bonds using their lone pair of electorn on nitrogen atom. There is no such H-bonding in tertiary amines. XII U13-Organic Nitrogen XII U13-Organic Nitrogen - - - - R R R The boiling point of various amines follows the order, NH .. > (CH ) NH ..
> (CH ) N .. > > ° ° ° Amines have lower boiling point than alcohols because nitrogen has lower electronegative value than oxygen and hence the N-H bond is less polar than -OH bond. Table Boiling points of amines, alcohols and alkanes of comparable molecular weight. S.NO.
Compound Molecular mass Boiling point (K) . CH (CH ) NH . C H -NH-CH . (CH ) N .
CH CH(OH)CH . CH CH CH CH . ) Solubility Lower aliphatic amines are soluble in water, because they can form hydrogen bonds with water molecules. However, solubility decreases with increase in molecular mass of