Ch. 8: Carboxylic Acids Flashcards
when is the -oic acid suffix used
when carboxylic acid is the highest priority functional group
when is the suffix carboxylic acid used
when cycloalkanes have carboxylic acid substituents
when is the -oate suffix used
when a carboxylic acid deprotonates and becomes a salt with a cation
what are dicarboxylic acids
molecule with carboxylic acid on each end
how are properties of carboxylic acids unique from ketone and aldehydes
additional -OH group allows for hydrogen bonding and can participate in reactions (when H+ deprotonates)
dimers
pairs of molecules connected by two hydrogen bonds
how do substituents affect carboxyl acidity
- electron withdrawing groups increase acidity (-NO2)
- electron donating groups decrease acidity (-NH2, -OCH3)
greater effect when closer to carboxyl
acidity in dicarboxylic acids
second groups is less acidic (harder to remove) than the first because two negative groups repel each other
what reagents will synthesize carboxylic acids from aldehydes/alcohols
oxidizing agents Na2Cr2O7, K2Cr2O7, CrO3, KMnO4
primary alcohols only!!
Steps of nucleophilic acyl substitution
Nucleophile adds to carbonyl –> tetrahedral intermediate with negative charge on oxygen –> negative charge reforms carbonyl and forces out leaving group
what is an amide
nitrogen group bonded to carbonyl group
what are lactams
cyclic amides
what are esters
ether bonded to carbonyl group
how are esters formed
under acidic conditions carbonyl oxygen is protonated, then carbonyl carbon is attacked by a primary oxygen
how are amides formed
nucleophilic acyl substitution of carbonyl group with an incoming nitrogen group under acidic or basic conditions
what are lactones
cyclic esters
what are anhydrides
two carboxylic acids with an ester linkage
how are anhydrides formed
condensation of two carboxylic acids
what reagent will reduce a carboxylic acid to a primary alcohol
LiAlH4
** NaBH4 is a reducing agent, but not strong enough for this rxn **
what is the leaving group in a decarboxylation reaction
a carboxyl group is completely lost as a carbon-dioxide leaving group
decarboxylation mechanism
intramolecular reaction
molecule rotates to produce six-membered ring transition state, the product tautomerizes from enroll to more stable keto form
what occurs during a saponification reaction
long-chain carboxylic acid + NaOH OR KOH produce salt (-OH group is deprotonate and cation is attracted to O-)
becomes a soap that will solvate nonpolar molecules –> micelle formation
