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Flashcards in Carboxylic acid Deck (162):
1

What is the functional group of a carboxylic acid?

carboxyl group (carbonyl group + hydroxyl group)

2

What is the general formula for an aliphatic carboxylic acid?

RCOOH

3

How do you name a carboxylic acid?

derived from the parent alkane by dropping the suffix -e and adding -oic acid

4

Why do you not need to give the carboxyl group a number?

Because it is understood to be carbon 1 because it is the highest priority functional group

5

How do you name a dicarboxylic acid?

Named as a -dioic acid and the longest chain contains both carboxyl carbons

6

Describe the polarity of carboxyl group (2 components)

1. polar hydrophilic carboxyl group (incease solubility)
2. nonpolar hydrophobic hydrocarbonchain (decrease solubility)

7

Why do carboxylic acids have high boiling points?

Because they are associated by hydrogen bonding into dimers

8

Explain the increased acidity of carboxylic acids

1. charge delocalization through resonance in a carboxylate anion relative to an alkoxide ion
2. the electron-withdrawing inductive effect of the carbonyl group

9

pKa tells you the acidity of what?

The hydrogen atom in the molecule

10

pH tells you the acidity of what?

The solution

11

Write the equilibrium formula for acid HA with water

HA + H2O A- + H3O

12

Write the equilibrium formula for acid HA with water

HA + H2O A- + H3O

13

Why can all molecules be considered amphoteric?

Because they can always be protonated/deprotonated by a stronger acid/base

14

The pH of a solution depends on what two things?

1. The concentration of the solution
2. The acid in question

15

Write the acidity constant Ka for the equilibrium reaction of an acid with water

Ka = [H3O][A-]/[AH}

16

What is the logarithmic form of the acidity constant?

pKa = -logKa

17

A stronger acid has a lower pKa or a higher pKa?

the lower the pKa the higher the Ka and the stronger the acid

18

Rearrange the expression for Ka to show that pKa is the pH at which an acid is exactly half dissociated

1. Ka = [H3O][A-]/[AH]
2. [H3O] = Ka * [AH]/[A-]
3. pH = pKa - log [AH]/[A-]

19

At pH above the pKa, how does an acid exist?

Acid exists as A- in water and will be fairly soluble

20

At pH below the pKa, how does an acid exist?

Acid exists mostly as AH in water and will be less soluble

21

How are pKa and stability of conjugate base related?

More stable conjugate base has a higher Ka becuase they give up a proton more, and therefore have a lower pKa.

22

How are pKa and stability of conjugate base related?

More stable conjugate base has a higher Ka becuase they give up a proton more, and therefore have a lower pKa.

23

Explain the increased acidity of carboxylic acids compared to alcohols (2 components)

1. charge delocalization through resonance in a carboxylate anion relative to an alkoxide ion
2. electron withdrawing inductive effect of the carbonyl group

24

What are three ways to prepare a carboxylic acid?

1. Oxidation of primary alcohols and aldehydes
2. Treating a grignard reagent with carbon dioxide
3. Treating a nitrile with water

25

Explain the problem with the reduction of carboxylic acids

Only LiAlH4 will reduce them. This means you can reduce other functional groups without worrying about carboxyl group.

26

Define fischer esterification

Prepration of an ester by treating a carboxylic acid with an alcohol in the presence of an acid catalyst such as a sulfuric acid

27

What is a powerful reagent for Fischer esterification and what product does it yield?

DIazomethane (CH2N2) gives a methyl ester in high yield.

28

How do you prepare an acid chloride from a carboxyl group?

Treatment with thionyl chloride

29

What is decarboxylation

Loss of CO2

30

What carboxylic acids undergo decarboxylation

1. All carboxylic acids to some extent with enough heat
2. Carboxylic acids with a (second) carbonyl group Beta to the carboxyl group undergo undergo mild heating.

31

What is the IUPAC name of HCOOH

Methanoic acid

32

What is the common name of HCOOH

Formic acid

33

What is the IUPAC name of CH3COOH

Ethanoic acid

34

What is the common name of CH3COOH

Acetic acid

35

What is the IUPAC name of CH3CH2COOH

Propanoic acid

36

What is the common name of CH3CH2COOH

Propionic acid

37

What is the IUPAC name of CH3(CH2)2COOH

Butanoic acid

38

What is the common name of CH3(CH2)2COOH

Butyric acid

39

What is the IUPAC name of CH3(CH2)3COOH

Pentanoic acid

40

What is the common name of CH3(CH2)3COOH

Valeric acid

41

What is the common name of CH3(CH2)3COOH

Valeric acid

42

What is the IUPAC name for salicylic acid?

o-hydroxybenzoic acid

43

Electron-donating groups are what type of directing groups in EAS?

Ortho and para directing

44

Electron-withdrawing groups are what type of directing group in EAS?

Meta directing

45

What is the common name for HOOCCOOH

Oxalic acid (2 carbon dioic acid)

46

What is the common name for HOOC(CH2)COOH

Malonic acid (3 carbon dioic acid)

47

What is the common name for HOOC(CH2)2COOH

Succinic acid (4 carbon dioic acid)

48

What is the common name for HOOC(CH2)3COOH

Glutaric acid (5 carbon dioic acid)

49

What is the common name for HOOC(CH2)4COOH

Adipic acid (6 carbon dioic acid)

50

What is the common name for a carboxylic acid with a 12-carbon chain?

lauric acid

51

What is the common name for a carboxylic acid with a 14-carbon chain?

myristic acid

52

What is the common name for a carboxylic acid with a 16-carbon chain?

palmitic acid

53

What is the common name for a carboxylic acid with a 18-carbon chain?

stearic acid

54

How do you name an acid chloride?

-ic acid replaced by -yl chloride

55

How do you name an amide?

-ic/-oic acid replaced by -amide

56

How do you name an ester?

1. -ic acid replaced by -ate
2. precede name by alkyl or aryl group bonded to oxygen (R')

57

How do you name an anhydride?

acid replaced by anhydride

58

How do you name the salt of a carboxylic acid?

1. Replace the -ic/-oic acid with -ate
2. Precede name by name of counterion

59

How do you name an anhydride if the acyl groups are different?

List the groups in alphabetical order

60

What is an acyl group?

R-CO -

61

What are the five most important carboxylic acid derivatives?

1. acid halides
2. acid anhydrides
3. esters
4. amides
5. nitriles

62

What are acid halides?

Acyl group bonded to a halogen

63

What are acid anhydrides?

Two acyl groups bonded to an O atom

64

What are esters?

Acyl group bonded to an -OR group

65

What are amides?

Acyl group bonded to an N atom

66

What are nitriles?

A cyano group bonded to a carbon

67

What are lactones?

Cyclic esters in which the acyl carbon and O atom are part of the ring

68

What are lactams?

cyclic amides in which the acyl carbon and the N atom are part of the ring

69

What are imides?

Two acyl groups attached to the same N atom

70

How do you name an lactone??

1. IUPAC: Count number of carbons from carboxyl carbon to the carbon that is bonded to Sp3 oxygen, drop -ic acid and name it -olide
2. Common name: count carbons the same way, drop -ic acid and name it -olactone, indicate substitutions with greek letters.

71

How do you name an lactone??

1. IUPAC: Count number of carbons from carboxyl carbon to the carbon that is bonded to Sp3 oxygen (count around the ring), drop -ic acid and name it -olide
2. Common name: count carbons the same way, drop -ic acid and name it -olactone, indicate substitutions with greek letters.

72

How do you name a lactam?

IUPAC: Count number of carbons from carboxyl carbon to the carbon that is bonded to N (count around the ring) drop -ic acid and name it -lactam

73

How do you name an imide?

Similar to an anhydride; name acyl group as a carboxylic acid derivative; drop -ic/-oic acid and add amide.(alphabetical order if different) and

74

How do you indicate substitutions on an amide?

Indicate substitutions on N-atom in the name by preceding the group with N (i.e. N-methyl)

75

Rank Carboxylic acid, acid halides, acid anhydrides, esters, amides and nitriles by their solubility from least soluble to most soluble

1. Ester
2. Nitrile
3. Amide
4. Carboxylic acid
5. Acid halides and acid anhydrides react with water (hydrolysis)

76

Rank Carboxylic acid, acid halides, acid anhydrides, esters, amides and nitriles by their solubility from least soluble to most soluble

1. Ester
2. Nitrile
3. Amide
4. Carboxylic acid
5. Acid halides and acid anhydrides react with water (hydrolysis)

77

Rank Carboxylic acid, acid halides, acid anhydrides, esters, amides and nitriles by their boiling point from least to highest boiling

1. Nitrile
**2. Ester (similar to hydrocarbons)
3. Acid halide
4. Anhydride
**5. Carboxylic acid (above 10 carbons are solid at room temp)
**6. Amide

78

Rank Carboxylic acid, acid halides, acid anhydrides, esters, amides and nitriles by their boiling point from least to highest boiling

1. Nitrile
**2. Ester (similar to hydrocarbons)
3. Acid halide
4. Anhydride
**5. Carboxylic acid (above 10 carbons are solid at room temp)
**6. Amide

79

What are the two steps in nucleophilic acyl substitution?

1. A strong nucleophile adds directly to acyl carbon, breaking C=O pi bond and creating a tetrahedral addition intermediate (a weaker nucleophile can be catalyzed by acid)
2. Tetrahedral intermediate collapses by losing a leaving group and reforming the C-O pi bond.

80

Rank the leaving group ability of amides, esters, anhydrides and acid halides from best leaving group to worst

1. Acid halides
2. Anhydride
3. Ester
4. Amide

81

What are two factors influencing the relative reaction rates of the carboxylic acid derivatives to acyl substitution?

1. Relative leaving group ability
2. Relative resonance stabilization

82

How does resonance stabilization affect rate of acyl substitution?

If a molecule is more stabilized by resonance it is less likely to react (the partial positive charge is removed from the carbon).

83

Rank the relative resonance stabilization from least stabilized to best

1. Acid halide
2. Anhydride
3. Ester
4. Amide

84

Rank the relative resonance stabilization from least stabilized to best

1. Acid halide
2. Anhydride
3. Ester
4. Amide

85

What does catalysis refer to in carboxylic acid chemistry?

When converting between functional groups, acid halide and anhydride are reactive enough that common nucleophiles will react directly. But esters and amides require acid or base catalysis.

86

What is the theory behind base catalysis?

Base is used to increase nucleophilicity by converting a neutral nucleophile to an anionic nucleophile

87

What is the theory behind acid catalysis? (2 components)

Acid is used to (1) increase positive charge on carbonyl carbon by protonating carbonyl oxygen OR (2) used to protonate a leaving group to allow it to leave as a stable molecule

88

What is the theory behind acid catalysis? (2 components)

Acid is used to (1) increase positive charge on carbonyl carbon by protonating carbonyl oxygen OR (2) used to protonate a leaving group to allow it to leave as a stable molecule

89

What is the mechanism for Fischer esterification

1. Protonate carbonyl group
2. Make a new bond between carboxyl carbon and alcohol. Deprotonate alcohol
3. Protonate carboxyl group. Leave as stable water.
4. Deprotonate alcohol to restore original carbonyl group.

90

What is the mechanism for Fischer esterification

1. Protonate carbonyl group
2. Make a new bond between carboxyl carbon and alcohol. Deprotonate alcohol
3. Protonate carboxyl group. Leave as stable water.
4. Deprotonate alcohol to restore original carbonyl group.

91

What are four (4) carboxylic fatty acids?

1. Lauric (12)
2. Myristic (14)
3. Palmitic (16)
4. Stearic (18)

92

What are four oxidation reactions to prepare a carboxylic acid?

1. Oxidation of arene side chain
2. Oxidation of primary alcohols
3. Oxidation of aldehydes
4. Oxidative cleavage (tautomerization) of alkynes

93

How do you prepare a carboxylic acid by oxidation of arene side chain?

Hot KMnO4, H2O will oxidize all benzylic carbons with at least one hydrogen to carboxyl groups.

94

How do you prepare a carboxylic acid by oxidation of primary alcohols?

Chromic acid

95

How do you prepare a carboxylic acid by oxidation of aldehydes?

Tollen's reagent (Ag+ in NH4OH)

96

How do you prepare a carbxylic acid by oxidative cleavage?

Hg2+, H2SO4 or

1) BH3 2)H2O2, NaOH

97

What are two unique synthetic methods for a carboxylic acid and what is unique about them?

1. Hydrolysis of nitriles
2. Carboxylation of organometallic reagents

Both methods increase chain size by 1.

98

Explain the hydrolysis of nitriles method of preparing a carboxylic acid

1. Sn2 reaction of CN- with an alkyl halide
2. Nitrile is put with water; similar addition of water across triple bond and tautomerization. NH4+ leaves

99

Explain the carboxylation of organometallic reagents method of preparing a carboxylic acid

Grignard reagent is treated with CO2 and H3O+. Results in a carboxyl carbon being added to the alkyl group of grignard reagent.

100

Explain the carboxylation of organometallic reagents method of preparing a carboxylic acid

Grignard reagent is treated with CO2 and H3O+. Results in a carboxyl carbon being added to the alkyl group of grignard reagent.

101

What reagents are used to convert a carboxylic acid into an ester?

Acid and R-OH

102

What reagents are used to convert a carboxylic acid into an acid chloride?

SOCl2

103

What reagents are used to convert a carboxylic acid into an amide?

NH3 (or a derivative)

104

What reagents are used to convert a carboxylic acid into an anhydride?

An acid chloride and carboxylic acid.

105

How do you predict the product of the reaction between an acid chloride and a carboxylic acid to form an anhydride?

Take both acyl groups and bond them to a common -O-.

106

Predict the product of an acid chloride reacting with water.

Cl is substituted for -OH.

107

How do you convert an acid chloride to an aldehyde?

LiAlH(Ot-Bu)3

108

How do you convert an acid chloride to an ester?

R-OH

109

How do you convert an acid chloride to an amide?

React with ammonia or primary/secondary amine (mono/disubstituted ammonia)

110

How do you convert an acid chloride to a ketone?

Organocuprate reagent

111

How do you convert an acid anhydride to a carboxylic acid?

Acid anhydrides react with water to form carboxylic acids.

112

How do you convert an acid anhydride to an ester?

Acid anhydride + R-OH ---> Ester and Carboxylic acid

113

Predict the product of an acid anhydride with an alcohol.

Break the bond between the two acyl groups; attach hydrogen to one of the oxygens (carboxylic acid product) and the alkyl group on the alcohol to the other acyl group (ester product).

114

How do you convert an acid anhydride to an amide?

Acid anhydrides react with primary and secondary amines to form amides.

115

Predict the products of an acid anhydride with an alcohol.

Break the bond between the two acyl groups; attach hydrogen to the carbon containing the oxygen (carboxylic acid product) and the alkoxy group from the alcohol to the other acyl group (ester product).

116

How do you convert an acid anhydride to an amide?

Acid anhydrides react with primary and secondary amines to form amides.

117

Predict the products of an acid anhydride with a primary or secondary amine.

Break the bond between the two acyl groups; attach amine minus one hydrogen to the carboxyl carbon (amide product) and form a salt with the protonated amine and the remaining carboxylate ion

118

How do you convert an acid anhydride to an ester?

Acid anhydride + R-OH --->(Pyridine) Ester and Carboxylic acid

119

Predict the products of an acid anhydride with a primary or secondary amine.

Break the bond between the two acyl groups; attach amine minus one hydrogen to the carboxyl carbon (amide product) and form a salt with the protonated amine and the remaining carboxylate ion

120

What is acid catalyzed hydrolysis of an ester?

Esters can be cleaved back into a carboxylic acid and an alcohol by reaction with water and a catalytic amount of acid.

121

Predict the products of an ester in acid catalyzed hydrolysis

The acyl alkyl group forms a carboxylic acid and the ester alkyl group forms an alcohol.

122

How do you prepare a tertiary alcohol from an ester?

Addition of grignard reagents converts esters to tertiary alcohols.

123

Predict the products of grignard addition to an ester

Alkyl group from grignard reagent adds twice to ester. The original ester -OR group is converted to an alcohol by addition of H.

124

How do you prepare a primary alcohol from an ester?

Esters can be converted to primary alcohols using LiAlH4

125

Predict the products of an ester in LiAlH4

1. Remove the carbonyl oxygen and convert -OR to -OH to get primary alcohol product.
2. Original ester -OR group is protonated to form additional alcohol product.

126

How do you prepare an amide from an ester? (2 methods)

1. Liquid ammonia at -70 degrees Celsius forms an amide and an alcohol.
2. aqueous ammonia at -10 degrees Celsius for one hour

127

Predict the products of an ester in liquid or aqueous ammonia

substitute -OR on ester for -NH2 and protonate the original ester -OR to form an alcohol.

128

Predict the products of an ester in liquid or aqueous ammonia

substitute -OR on ester for -NH2 and protonate the original ester -OR to form an alcohol.

129

How do you prepare an aldehyde from an ester?

Esters can be converted to aldehydes using diisobutylaluminum hydride (DIBAH).

130

Predict the products of an ester in DIBAH

substitute the -OR on ester for an H to form aldehyde product. protonate original ester -OR to form an alcohol product.

131

What is transesterification?

When one ester is converted into another by an exchange of alkoxy groups.

132

What are the reaction conditions for transesterification?

The most common method is a large excess of alcohol with an acid catalyst such as H2SO4.

133

Predict the products for RCOOR' + R''-OH

RCOOR'' + R'-OH (exchange alkoxy groups)

134

What is saponification of an ester?

Hydrolysis (ester -> carboxylic acid + alcohol) using water and NaOH (basic)

135

Predict the products of an ester in H2O/NaOH

The products are a carboxylate ion (carboxylic acid is deprotonated because of basic conditions) and an alcohol form from the ester -OR group.

136

Predict the products of an ester in H2O/NaOH

The products are a carboxylate ion (carboxylic acid is deprotonated because of basic conditions) and an alcohol form from the ester -OR group.

137

How do you prepare an amide from a nitrile?

Nitriles can be converted to amides when acid catalyzed by HCl at 40 degrees celsius.

138

How do you prepare a nitrile from a primary amide?

primary amides can be converted to nitriles by reaction by dehydration with thionyl chloride (SOCl2)

139

Predict the products of a primary amide in SOCl2

Replace CONH2 carbon of primary amide with CtriplebondN

140

How do you prepare an amine from an amide?

Amides can be converted to 1°, 2° or 3° amines using LiAlH4.

141

Predict the products of a primary, secondary or tertiary amine in LiAlH4

Remove the carbonyl oxygen.

142

What are the two types of hydrolysis of amides?

1. Hydrolysis under acidic conditions
2. Hydrolysis under basic conditions

143

What are the products when amides are hydrolyzed under acidic conditions (HCl)?

A carboxylic acid and an ammonium chloride.

144

What are the products when amides are hydrolyzed under alkaline conditions (OH-)?

Sodium carboxylate and ammonia.

145

What are the two types of hydrolysis of amides?

Both require severe conditions (heat):
1. Hydrolysis under acidic conditions
2. Hydrolysis under basic conditions

146

What are the products when amides are hydrolyzed under alkaline conditions (OH-)?

Sodium carboxylate and ammonia.

147

How can you form an imide?

A difunctional molecule containing an amide and a carboxylic acid can dehydrate to form an imide with heat.

148

Predict the product of a amide/carboxylic acid molecule forming an imide.

Remove hydroxyl and a hydrogen from the nitrogen and create a new bond between nitrogen and the other acyl carbon.

149

Predict the product of a amide/carboxylic acid molecule forming an imide.

Remove hydroxyl and a hydrogen from the nitrogen and create a new bond between nitrogen and the other acyl carbon.

150

What is the product of Claisen condensation?

A beta-ketoester.

151

What are the reactants and the reaction conditions for Claisen condensation?

Two molecules of an ester with a strong nonaqueous base like sodium ethoxide in ethanol.

152

Describe how the Claisen reaction works (3 steps)

1. A strong base removes an alpha-hydrogen from an ester to form an enolate ion which is a nucleophile for addition to an ester.
2. The -OR (alkoxy) of the ester leaves as a strong base then deprotonates the carbon tethered between carbonyl carbons forming a weak base (enolate ion) and an alcohol.
3. Mild acid is added to protonate enolate ion to give the beta-ketoester.

153

Distinguish between Amine, Amide, Imine, Imide

-ides are acyl group containing compounds:
1. Amine: Ammonia derivative
2. Amide: Carboxylic acid derivative, -OH replaced by -NH2
3. Imine: C=N
4. Imide: two acyl groups bound to nitrogen

154

Explain why the reaction of an acid chloride with ammonia to form an amide is spontaneous (2 components)

The acid chloride is a strong leaving group than the NH2 and the amide is more stable than the acid chloride because of resonance stabilization.

155

What are the reagents to halogenate an aromatic ring?

X2, FeX3

156

What are the reagents for friedal crafts acylation

RCOCl + AlCl3

157

Predict the products of an acid anhydride with a primary or secondary amine.

Break the bond between the two acyl groups; attach amine minus one hydrogen to the carboxyl carbon (amide product) and form a salt with the protonated amine and the remaining carboxylate ion

158

Explain why the reaction of an acid chloride with ammonia to form an amide is spontaneous/favorable (2 components)

The acid chloride is a strong leaving group than the NH2 and the amide is more stable than the acid chloride because of resonance stabilization.

159

What are the reagents for friedal crafts acylation

RCOCl + AlCl3

160

Explain why Thioesters are more reactive to nucleophilic acyl substitution than ordinary carboxylic esters

Weaker bases are better leaving groups and RS- (thiolate) is a weaker base than RO- (alkoxide)

161

Predict the product for benzoic acid with sodium bicarbonate.

Sodium benzoate and carbonic acid (strong acid makes weaker acid)

162

Predict the product for benzoic acid with sodium bicarbonate.

Sodium benzoate and carbonic acid (strong acid makes weaker acid)