Chapter 20 Flashcards
The combination of a carbonyl group and a hydroxyl group on the same carbon atom is called a _______
carboxyl group
Terminology:
1) -COOH:
2) R-COOH:
3) R-COO(-)
1) carboxyl
2) carboxylic acid
3) carboxylate ion
Classification of carboxylic acids:
1) _______ acids: have an alkyl group bonded to the carboxyl group
2) _______ acids: have an aryl group
3) _______ acids: long chain of aliphatic acids
1) aliphatic
2) aromatic
3) fatty
- more than 14 C
Common naming of carboxylic acids:
The position of substituents is labeled with Greek letters starting with the C atom next to the carboxyl carbon. What is the order?
1) α
2) β
3) γ
4) δ
5) ε
- Carboxylic carbon doesnt count towards greek letters
IUPAC:
1) remove the -e from the alkane name and replace it with the ending _______
2) the carbon of the carboxyl group is number _____
3) the carboxyl group takes priority over all functional groups
1) oic acid
2) 1
3) highest priority
IUPAC:
Unsaturated acids are named using the name of the corresponding alk___e, or alk___e with the final -e replaced by -oic acid
en
yn
IUPAC:
If carboxylic acid on benzene then it is called _______
benzoic acid
IUPAC:
if 1 carboxylic acid attached to a ring, then name it like a cycloalkane followed by ending _______
carboxylic acid
IUPAC:
Dicarboxylic acids named simply by adding the suffix _______
- if cyclic then treat it as a _______
Dioic acid
ex) 2-phenyl-pentanedioic acid
substituent
ex) 1,3-cyclopentane dicarboxylic acid
If there’s a cyclic dicarboxylic acid, then the suffix _______ is used
dicarboxylic acid
- add after root
ex) 1,3-cyclopentane dicarboxylic acid
Structure of carboxyl group:
- the sp2 hybrid carbonyl C atom is _______, with nearly trigonal bond angles
- the OH bond also lies in this plane, _______ with the C=O bond
planar
eclipse
Carboxylic acids boil at considerably _______ temps than alcohols, ketones, or aldehydes of similar weight because the carboxylic acids form a stable hydrogen bond _______
higher
dimer
Aliphatic acids with more than _____ carbons are solids at room temperature
8
Double bonds (especially cis) _______ the melting point
lower
ex) on 20-3 in notes
Solubility:
- Water solubility of carboxylic acids _______ with the increasing length of the carbon chain (@ how many carbons is it immiscible)
- very soluble in _______
- Soluble in _______ solvents like chloroform: H-bonds of the dimer are not disrupted by the nonpolar solvent
decrease
- 5 or more carbons
alcohol
non-polar
What are the 2 main factors that determine acidity of carboxylic acids?
1) resonance
- quality over quantity
2) substituent effects
- quantity or distance
- EWG :)
- EDG :’(
In aromatic rings, acidity effects are strongest for substituents in the _______ and the _______ positions (mainly)
ortho
para
- for EWG
CA reacts with bases such as NaOH and NaHCO3 to form _______
carboxylate salt
The basic hydrolysis of fats and oils produces soap, this reaction is known as _______) forms fatty acid salt which is “soap”
saponification
A bunch of soap molecules is called a _______ which has the polar carboxylate ion (outside) and nonpolar hydrocarbon (inside)
micelle
What kind of oxidation should you do to form Carboxylic acid from 1° alcohols and aldehydes? (3)
1) excess NaOCl, TEMPO
2) Cr reagent with acid
- Na2Cr2O7, H2SO4
3) Ag2O
- only aldehydes
What reagents should you use to form CA from alkenes?
1) KMnO4 , acid
- any H on the double bond turns into OH in addition to adding a carbonyl to C
What reagents should you use to turn an alkyne into carboxylic acid?
KMnO4
or
1) O3 2)H2O
What reagents should you use for side-chain oxidation of alkylbenzenes to CA?
1) Na2Cr2O7, H2SO4, heat
2) KMnO4, H2O, heat
What is the best carbonyl compound to use when creating CA from a Grignard reagent?
CO2 (s)
in order to go from a nitrile to a carboxylic acid, _______ must occur. What are the reagents for the acidic version and basic version
hydrolysis
acidic: H3O+
basic: 1) -OH, H2O 2) H3O+
In what scenarios would nitrile hydrolysis be better than grignard for formation of the CA?
nitrile: 1° or 2° alkyl halide
grignard: 3° alkyl halide or halide on double bond
What are the 3 parts that signal Fischer esterification?
1) CA
2) alcohol (ROH)
3) Acid (H2SO4)
In order for the reaction to favor the products in Fischer esterification, what can you do?
1) remove water
2) add excess reactant (ROH or acid)
Carboxylic acids are converted to their methyl esters very simply by adding an ether solution of _______
diazomethane
What is the driving force of formation of esters from CA using diazomethane?
N2+ group leaving as gas
- reaction is irreversible
The initial reaction of carboxylic acid with an amine gives the _______. Then heating drives off the steam, causing the _______ to form
1) ammonium carboxylate salt
- via acid-base reaction
2) amide
LiAlH4 reduces carboxylic acids to _______ alcohols
1°
The first td intermediate in the LiAlH4 mechanism is formed from _______ while the second is formed from _______
1) acyl substitution
2) acyl nucleophile addition
_______ can be used to selectively reduce carboxylic acid to a 1° alcohol
1) Borane (BH3), 2) H2O
- doesn’t react with aldehydes and ketones
- is a 2 step process
What are the 2 reagents you can use to turn a carboxylic acid into an acid chloride? What byproducts do they form?
1) SOCl2
- SO2 gas byproduct
2) (COCl)2
- CO2 gas byproduct
Nucleophilic acyl substitution using acid chloride and alcohol is _______ efficient than Fischer esterification
more
- FE lim: reversible
- CH2N2 lim: only methylesters
