DERIVATIVES OF CARBOXYLIC ACIDS. (CH 3 CO) 2 O ethanoic anhydride

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Ambrose Kelley
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1 Acylation A4 1 DEIVATIVES F ABXYLI AIDS AYL (AID) LIDES - l named from corresponding acid remove -ic add -yl chloride l 6 5 l ethanoyl chloride benzene carbonyl chloride δ l δ δ bonding in acyl chlorides AID ANYDIDES - () 2 named from corresponding acid remove acid add anhydride ( ) 2 ethanoic anhydride δ δ δ δ δ bonding in acid anhydrides hemical Properties colourless liquids which fume in moist air acyl chlorides are more reactive than anhydrides attacked at the positive carbon centre by nucleophiles nucleophiles include water, alcohols, ammonia and amines undergo addition-elimination reactions Uses of Acylation Industrially Manufacture of ellulose acetate - making fibres Aspirin (acetyl salicylic acid) - analgaesic Ethanoic anhydride is more useful cheaper less corrosive less vulnerable to hydrolysis less dangerous reaction Laboratory Used to make carboxylic acid, esters, amines, N-substituted amines Ethanoyl chloride is used as it is more reactive gives a cleaner reaction Q.1 Investigate how aspirin is made industrially and in the laboratory. Why are the reagents and chemicals different? What properties of Aspirin make it such a useful drug?

2 2 A4 Acylation ADDITIN ELIMINATIN EATINS - VEVIEW species attacked by nucleophiles at the positive carbon end of the = bond the nucleophile adds to the molecule either l or is eliminated a proton is removed General example - with water AID LIDES l l l l l 2 > l AID ANYDIDES () 2 2 > 2 Use these mechanisms to help construct others in the spaces which follow SYNTETI PSSIBILITIES AYL LIDE PDUT WIT WATE ALLS AMMNIA AMINES ABXYLI AID ESTE N-SUBSTITUTED By-product l AID ANYDIDE ABXYLI AID ESTE N-SUBSTITUTED ABXYLI AID

3 Acylation A4 3 ADDITIN ELIMINATIN - the reactions AYL (AID) LIDES - l Water Product(s) carboxylic acid l (fume in moist air / strong acidic solution formed) onditions cold water Equation l (l) 2 (l) > (aq) l (aq) addition-elimination l l l l Alcohols Product(s) ester hydrogen chloride onditions reflux in dry (anhydrous) conditions Equation l (l) (l) > (l) l (g) addition-elimination l l l l Q.2 What organic product is formed when the following pairs react? 3 7 l and l and 2 5 Q.3 ow would you synthesis the following? methyl butanoate butyl methanoate 6 5 ( ) 2

4 4 A4 Acylation Ammonia Product(s) Amide hydrogen chloride onditions Low temperature and excess ammonia. Vigorous reaction. Equation l (l) N 3(aq) > N 2(s) l (g) or l (l) 2N 3(aq) > N 2(s) N 4 l (s) addition-elimination l l N N l N N 2 l Amines Product(s) N-substituted amide hydrogen chloride onditions anhydrous Equation l (l) 2 5 N 2(aq) > N 2 5(s) l (g) or l (l) N 2(aq) > N 2 5(s) 2 5 N 3 l (s) addition-elimination - similar to that with ammonia l l N N l N N l Q.4 Why are two moles of ammonia (or amine) required in each equation? Q.5 What pairs of chemicals would you use to synthesis the following? butanamide 2 5 N 2 N( ) 2 N-phenylethanamide

5 Acylation A4 5 AID ANYDIDES - () 2 Water Product(s) carboxylic acid (weak acidic solution formed) onditions cold water - but can be slow Equation ( ) 2 (l) 2 (l) > 2 (aq) Alcohols Product(s) ester carboxylic acid onditions reflux in dry (anhydrous) conditions Equation ( ) 2 (l) (l) > (l) (aq) Q.6 What organic product(s) is/are formed when the following pairs react? ( 3 7 ) 2 and 2 ( ) 2 and 2 5 ( ) 2 and ( ) 2

6 6 A4 Acylation Ammonia Product(s) Amide carboxylic acid onditions Low temperature and excess ammonia. Equation ( ) 2 (l) N 3(aq) > N 2(s) (aq) or ( ) 2 (l) 2N 3(aq) > N 2(s) N 4 (s) Amines Product(s) N-substituted amide carboxylic acid Equation ( ) 2 (l) 2 5 N 2(aq) > N 2 5(s) (aq) or ( ) 2 (l) N 2(aq) > N 2 5(s) N 4 (s) Q.7 What organic product(s) is/are formed when the following pairs react? ( 3 7 ) 2 and N 3 ( ) 2 and 2 5 N 2 ( ) 2 and ( ) 2 N

Ch17_PT MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

Ch17_PT MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Which molecule is a carboxylic acid? A) 1) B) C) D) E) CH3 CH2 CH2 NH2 2) Which molecule