Mcat Carboxylic Acids

Front 1

What is a carboxyl group?

Back 1

A carbonyl attached to a hydroxyl group

Front 2

Acetic acid is derived from __ via fermentation

Back 2

ethanol

Front 3

acid or base
what are CA's?

Back 3

acid

Front 4

When a CA does give away a proton, the leftover electrons are resonated b/w ___ atoms

Back 4

two oxygen

Front 5

CA has a hydrogen bond ___ and ___ in the same functional group, leading to ____ intermolecular forces and ___ B.P.'s

Back 5

donor, acceptor, large, high

Front 6

The carbonyl carbon is ____

Back 6

electropositive
*so it makes it a great electrophile

Front 7

CA's have the ___ priority in nomenclature

Back 7

highest

Front 8

t or f
CA's occur widely in nature and are synthesized by all living organisims

Back 8

t

Front 9

CA's are always named by adding the suffix...

Back 9

-oic acid

Front 10

What are the common and IUPAC names of the first 3 carboxylic acids?

Back 10

methanoic acid => formic acid
ethanoic acid => acetic acid
propanoic acid => propionic acid

Front 11

Cyclic carboxylic acis are usually names as what?

Back 11

cycloalkane CA's

Front 12

Salts of CA's are named beginning with the ___, followed by the ____.

Back 12

cation, name of the acid with the ending -ate

Ex) Sodium hexanoate

Front 13

What is a dicarboxylic acid?

Back 13

Molecules with two carboxyl groups on the same molecule

Front 14

What are the first 6 straight chain terminal dicarboxylic acids?

Back 14

oxalic
malonic
succinic
glutaric
adipic
pimelic

Front 15

polar or non polar
What are CA's?

Back 15

polar

Front 16

Can CA's form hydrogen bonds with each other?

Back 16

yes

Front 17

As a result of hydrogen bonding CA's can form what?

Back 17

dimers

Front 18

Define dimers?

Back 18

pairs of molecules connected by two hydrogen bonds

Front 19

Multiple hydrogen bonds ___ the boiling and melting point of CA's

Back 19

elevate

Front 20

BP ___ with increasing MW

Back 20

increase

Front 21

CA's acidity is due to what?

Back 21

resonance stabilization of the carboxylate anion

Front 22

What happens when the hydroxyl proton dissociates from the acid?

Back 22

The negative charge left on the carboxylate group is delocalized b/w the two oxygen atoms

Front 23

Name 2 ways to stabilize the negative charge to increase acidity:

Back 23

1. electron withdrawing groups (halides)
2. groups that allow more resonance stabilization (benzyl or allyl)

Front 24

How does electron withdrawing groups influence acidity?

Back 24

Absorbs the negative charge and increases acidity

Front 25

How does electron donating groups influence acidity?

Back 25

Donates additional electron density and destabilizes the negative charge, making the compound less acidic

Front 26

In dicarboxylic acids, one -COOH group influences the other, making the compound what?

Back 26

more acidic

Front 27

Beta-dicarboxylic acids are notable for what?

Back 27

high acidity of the alpha-hydrogens located on the carbon b/w the two carboxyl groups

Front 28

CA's are the most ___.

Back 28

oxidized

Front 29

CA's can be prepared via oxidation of...

Back 29

aldehydes, primary alcohols, and certain alkylbenzenes

Front 30

What oxidant is normally used to oxidize CA's?

Back 30

KMnO4

Front 31

Why can't secondary and tertiary alcohols be oxidized to carboxylic acids?

Back 31

B/c of valence limitations

Front 32

Organometallic reagents react with ___ to form ___.

Back 32

CO2, CA's

Front 33

Give an example of an organometallic reagent

Back 33

Grignard reagents

Front 34

Carboxylation of organometallic reagents is useful for the conversion of ___ alkyl halides into CA's

Back 34

tertiary

Front 35

Carboxylation of organometallic reagents adds ___ carbon atom to the chain

Back 35

one

Front 36

Nitriles are also called what?

Back 36

cyanides

Front 37

HYDROLYSIS OF NITRILES
The cyanide anion carries the ___ charge on the ___ atom, making it a great ___, but not a great ___.

Back 37

negative, carbon, nucleophile, base

Front 38

HYDROLYSIS OF NITRILES
The cyanide anion will displace __ and ___ halides in a typical SN2 fasion

Back 38

primary and

Front 39

HYDROLYSIS OF NITRILES
Nitriles can be hydrolyzed under either __ or __ conditions

Back 39

acidic, basic

Front 40

HYDROLYSIS OF NITRILES
This reaction allows for the conversion of ___ into ___.

Back 40

alkyl halides, CA's

Front 41

HYDROLYSIS OF NITRILES
As in the carboxylation reaction, an additional __ is introduced into the chain

Back 41

carbon

Front 42

What do long chain carboxylic acids form when they react with sodium or potassium hydroxide?

Back 42

salt

Front 43

How do you make soap?

Back 43

by mixing fat (triglycerides) with lye (sodium hydroxide)

Front 44

Why can salts solvate nonpolar organic compounds in aqueous solutions?

Back 44

They possess both a nonpolar tail and polar carboxylate head

Front 45

Define micelles

Back 45

soap molecules that arrange themselves in spherical structures

Front 46

SOAP FORMATION
The ___ face outward, where they can be solubilized by water, the ___ are oriented inward where it is protected

Back 46

polar heads, nonpolar hydrocarbon chains

Front 47

Many of the reactions in which CA's participate proceed via a single mechanism called what?

Back 47

nucleophilic acyl substitution

Front 48

Nucleophilic acyl substitution is similary to...

Back 48

nucleophilic addition to a carbonyl

Front 49

Carboxylic acids and esters can only be reduced by __ and not the less reactive ___.

Back 49

LiAlH4, NaBH4

Front 50

most or least
CA's occupy the ___ oxidized end of the oxidation-reduction continuum

Back 50

most

Front 51

yes or no
Can CA's be further oxidized?

Back 51

no

Front 52

LAH reduces CA's to ___.

Back 52

alcohols

Front 53

Show reduction of a CA mechanism

Back 53

carboxylic acid => aldehyde => alcohol

Front 54

Reduction of a CA occurs by nucleophilic ____ of ____ to the carbonyl group

Back 54

addition, hydride

Front 55

How do you synthesize esters?

Back 55

react CA's with alcohols under acidic conditions

Front 56

Ester formation is a ____ reaction, so ___ is a side product.

Back 56

condensation, water

Front 57

ESTER FORMATION
In acidic conditions, the ___ on the C=O can be protonated. This enchances the ___ of the bond, putting more ___ charge on the C, and making it ___ susceptible to nucleophilic attack

Back 57

O, polarity, positive

Front 58

ESTER FORMATION
This condensation reaction occurs most rapidly with ___ alcohols

Back 58

primary

Front 59

Whats another name for acyl halides?

Back 59

acid halides

Front 60

What are acyl halides?

Back 60

Compounds with carbonyl groups bonded to halides

Front 61

How is thionyl chloride written?

Back 61

SOCl2

Front 62

What does thionyl chloride do?

Back 62

A reagent that can convert CA's into acyl halides

Front 63

reactive or nonreactive
Acid cholorides.

Back 63

reactive

Front 64

Acid chlorides are frequently used as ____ in the conversion of CA's to ___ and ___.

Back 64

intermediates, esters and amides

Front 65

What biochemical pathway is decarboxylation most common in?

Back 65

Krebs Cycle

Front 66

What is decarboxylation?

Back 66

loss of a carbon

Front 67

Whenever we want to get rid of a carbon on the MCAT, it will be lost in the form of ___?

Back 67

CO2

Front 68

t or f
Acid chlorides are most stable and least reactive

Back 68

f
Acid chlorides are the least stable and the most reactive

Front 69

____ and other ____ may spontaneously decarboxylate when heated.

Back 69

1,3 Dicarboxylic acids and other beta-keto acids

Front 70

DECARBOXYLATION
the carboxyl group is lost and replaced with what?

Back 70

hydrogen

Front 71

DECARBOXYLATION
Because both the electrophile and nucleophile are in the same molecule, the reaction proceeds....

Back 71

through a six membered ring transition state

Front 72

DECARBOXYLATION
The ___ that is initially formed from the destruction of the ring tautomerizes to the more stable __ form.

Back 72

enol, keto

Front 73

The more stable the ___ is, the more likely it is that the ___ will leave

Back 73

conjugate base, proton

Front 74

CA stability is determined by what 3 factors?

Back 74

-periodic trends (electronegativity, and thus, induction)
-size of the anion (HF is a weaker acid than HI)
-resonance

Front 75

The acidity of a CA is enhanced by...

Back 75

resonance b/w its oxygen atoms

Front 76

Primary alcohols or aldehydes can be ___ by CA's

Back 76

oxidized

Front 77

What 2 ways can CA's be synthesized?

Back 77

-from the carbocation of organometalic reagents
-by hydrolyzing nitriles

Front 78

Carboxylic acids can be reduced to primary alcohols or stopped at the aldehyde level with a...

Back 78

bulky hydride reagent

Front 79

CA's with long chains form soaps when neutralized with ___ or ___.

Back 79

NaOH or KOH

Front 80

1,3 Dicarboxylic acids and other beta-keto acids may spontaneously decarboxylate when heated producting...

Back 80

a ketone and carbon dioxide