Learning Guide for Chapter 24 - Carboxylic Acid derivatives

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LG Ch 24 p 10Base-catalyzed hydrolysis of esters is called saponification. It is not reversible because ofthe last acid-base reaction at the end.OOHOHOHThe term saponification comes from the original use of this reaction in making soap.Recall that saturated fats are triesters of long chain fatty acids and glycerol.Saponification yields the carboxylate anions of these fatty acids, which arrangethemselves as micelles and are good for dissolving dirt and grease. Base was obtainedfrom water soaked in wood ashes.OOOOOONaOHH 2 Oheat+HO3OHOHOONaAmides - require strongly acidic or basic conditions such as 6M HCl or 40% NaOH. Themechanisms are analogous to the ester mechanisms. Note that in both cases, theequilibrium is driven forward by a final acid-base reaction.OH 2 SO 4NH 2H 2 OONH 2NaOHH 2 O
LG Ch 24 p 11Nitriles can be hydrolyzed to amides using mild acid or base. Under more strenousconditions, the amide is then hydrolyzed to the carboxylic acid. You will not need toknow these mechanisms - they are similar to the ones we've discussed, with a few extratwists.NH 3 O +H 2 O, heatNNaOHH 2 O, heatVI. Interconversion of carboxylic acid derivativesAs a general rule, carboxylic acid derivatives can be converted into any other derivativethat is less reactive than the original. Esters can also be made into other esters by atransesterification reaction.carboxylic acidacid chloride anhydride ester amideThe only way to go from a more reactive to a less reactive derivative is to first hydrolyzeto the carboxylic acid.OOONH 2OHOThe general mechanism for converting a more reactive derivative into a less reactive oneis shown below. If the Nu originally had an H attached, it will be removed in anadditional step.ONuLGWhen making anhydrides, the nucleophile is a carboxylate anion. When making esters,the nucleophile may be an alcohol or an alkoxide. When making amides, the nucleophileis ammonia or an amine.OOOOR O RRORRNH
Page 1 and 2: Learning Guide for Chapter 24 - Car
Page 3 and 4: Esters can be formed from carboxyli
Page 5 and 6: LG Ch 24 p 5III. Nomenclature of ca
Page 7 and 8: 3-chloro-N-methylpentanamideN-benzy
Page 9: V. Hydrolysis of carboxylic acid de
Page 13 and 14: LG Ch 24 p 13If a mixed anhydride i
Page 15 and 16: LG Ch 24 p 15Acid chlorides can be
Page 17: LG Ch 24 p 17IX. Summary of reactio

Learning Guide for Chapter 24 - Carboxylic Acid derivatives

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