Ch.20 Flashcards
_____ acids have an alkyl group bonded to -COOH
aliphatic
fatty acids are long-chain ______ ______
aliphatic acids
The sp3 oxygen has a C—O—H angle of ______
106°
Carboxylic acids boil at considerably _______ temperatures than do alcohols, ketones, or aldehydes of similar molecular weights
higher
The high boiling points of carboxylic acids result from what?
formation of a stable, hydrogen-bonded dimer
Aliphatic acids with more than ____ carbons are solids at room temperature.
eight
How do double bonds effect the melting point?
Double bonds (especially cis) lower the melting point
Water solubility _____ with the length of the carbon chain
decreases
Acids with more than ____ carbon atoms are nearly insoluble in water
10
Carboxylic acids are very soluble in ______
alcohols
They are also soluble in relatively _____ solvents like chloroform because the hydrogen bonds of the dimer are not disrupted by the nonpolar solvent
nonpolar
acetate ion is _____ stable than an alkoxide ion
more
Electron-withdrawing groups _____ the acid strength, and electron-donating groups _______ the acid strength
enhance ; decrease
Effects are strongest for substituents in the ____ and ___ positions
ortho and para
The hydroxide ion completely deprotonates the acid to form the _______ ______
carboxylate salt
how do you name carboxylic acids salts?
- name the cation
- name the anion by replacing the -ic acid with -ate
The basic hydrolysis of ____ and ____ produces soap (this reaction is known as saponification).
fats and oils
carboxylic acid protons absorb between what?
10 and 13
The protons on the α carbon atom absorb between ____ and ____
2.0 and 2.5
The most common fragmentation is the loss of an alkene through the ______ ______
McLafferty rearrangement
Another common fragmentation is cleavage of the ____-_____ bond to form an alkyl radical and a resonance-stabilized cation
beta-gamma
What can you oxidized primary alcohols and aldehydes with?
chromic acid (H2CrO) + H2SO4
Cleavage of an alkene with hot KMnO4 produces what if there is a vinylic hydrogen present?
carboxylic acid
How are alkyl benzenes oxidized to benzoic acid?
hot KMnO4 or hot H2CrO4
How can a primary alcohol (R-CH2-OH) form a carboxylic acid (R-CO-OH)?
excess NaOCl, TEMPO
What reagents are used to cleave the C=C bond of an alkene (to an acid and ketone)?
warm, conc. KMnO4
What reagents are used to make alkynes into carboxylic acids?
conc. KMnO4 OR
1) O3
2) H20
What reagents are used to oxidize side chains of alkylbenzenes (CH3-CH-CH3) –> (COOH)?
Na2Cr2O7, H2SO4
heat
Grignard reagents react with _____ to produce, after protonation, a carboxylic acid.
CO2
The carboxylation of grignard reagents increases the number of carbonds in the molecule by ____
1
What is the Kolbe-Schmidt reaction?
- phenol to 2-hydroxybenzoic acid
- high pressure (100 atm)
- high temperature (125C)
Basic or acidic hydrolysis of a nitrile (-CN) produces what?
carboxylic acid
The basic or acidic hydrolysis of nitriles adds how many extra carbons to the molecule?
1
When an -OH is bonded to an aryl carbon, what is the class of the compound?
carboxylic acid
When an -Cl is bonded to an aryl carbon, what is the class of the compound?
acid chloride
When an -OR’ is bonded to an aryl carbon, what is the class of the compound?
ester
When an -NH2 is bonded to an aryl carbon, what is the class of the compound?
amide
What is the name of this acid derivative?
R-CO-OH
carboxylic acid
What is the name of this acid derivative?
R-CO-X
acyl halide
What is the name of this acid derivative?
R-CO-O-CO-R
anhydride
What is the name of this acid derivative?
R-CO-O-R’
ester
What is the name of this acid derivative?
R-CO-NH2
amide
Carboxylic acids react by ______ _______ _______, where one nucleophile replaces another on the acyl (C=O) carbon atom.
nucleophilic acyl substitution
What is the order of reactiveness (more reactive to less reactive) of the following acid derivatives: amide, ester, acid chloride, carboxylic acid?
acid chloride, ester, amide, carboxylic acid
What are the best reagents for converting carboxylic acids to acid chlorides?
SOCl2 and COCl2
Reduction of a carboxylic acid with an alcohol under acidic conditions produces what?
ester
What is the formula of diazomethane?
CH2N2
How are carboxylic acids converted to their methyl esters?
adding CH2N2
What is the structure of methyl ester?
R-CO-O-CH3
What are the properties of diazomethane?
toxic, explosive, yellow gas
Which is more efficient, Fischer esterification or esterification of an acyl chloride?
esterification of an acyl chloride
The initial reaction of a carboxylic acid with an amine gives an ________ __________ ________.
ammonium carboxylate salt
What reacts with acid chlorides to give amides?
ammonia and amines
What reduces carboxylic acids to primary alcohols?
LiAlH4
BH3 * THF will not reduce a _____
ketone
What does BH3 * THF reduce carboxylic acids to?
primary alcohols
Lithium aluminum tri(tert-butoxy)hydride is a _______ reducing agent than lithium aluminum hydride.
weaker
Why does lithium aluminum tri(tert-butoxy)hydride reduce acid chlorides?
they are strongly activated toward nucleophilic addition of a hydride ion