17c - carboxylic acids Flashcards

1
Q

what is the relative strength of carboxylic acids?

A

weak acids that dissociate partially

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2
Q

what is the name of the ion RCOO-?

A

carboxylate ion

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3
Q

describe the solubility of carboxylic acids in water.

A
  • hydrogen bonding up to C4
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4
Q

describe the hydrogen bonding between carboxylic acids.

A

pure liquid carboxylic acids form dimer with each other

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5
Q

in which 2 ways could carboxylic acids be made?

A

1- oxidation from primary alcohols
2- hydrolysis of nitriles

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6
Q

what are the reagents & conditions of hydrolysis of nitriles?

A

reagents - HCl (aq)
conditions - heat under reflux

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7
Q

what are the reagents & conditions of reduction of carboxylic acids? what is the product?

A

reagent - LiAlH4 in dry ether
condition - room temperature & Pa
carboxylic acid -> primary alcohol

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8
Q

what are the 2 tests for carboxylic acids?

A
  • test with carbonate - effervescence
  • test with PCl5 - HCl tested with NH3 produce white steamy fumes
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9
Q

what is an example of salt formed from reacting a carboxylic acid with a base?

A

CH3COO-Na+

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10
Q

how many [H] are needed in reduction of carboxylic acids?

A

4

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11
Q

what are the products of reacting PCl5 with carboxylic acids?

A

acyl chloride + POCl3 + HCl

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12
Q

how are esters formed? list the reagents & conditions.

A

reagents - carboxylic acid, alcohol, under H2SO4 catalyst
conditions - heat under reflux

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13
Q

how are esters seperated from the equilibrium mixture?

A

distillation is done in situ as reaction is reversible

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14
Q

why do esters not form hydrogen bonds?

A

hydrogen not bonded to highly electrogenative atom

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15
Q

what is the relative boiling point of an ester compared to its relative carboxylic acid?

A

lower

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16
Q

what are the products of acid hydrolysis?

A

carboxylic acids & alcohols

17
Q

what are the reagents & conditions of acid hydrolysis?

A

reagents - dilute acid catalyst
conditions - heat under reflux

18
Q

what are the problems of acid hydrolysis?

A

doesn’t produce a good yield since reaction is reversible

19
Q

what are the products of base hydrolysis?

A

carboxylate ion & alcohol

20
Q

what are the reagents and conditions of base hydrolysis?

A

reagents - NaOH
conditions - heat under reflux

21
Q

what is the difference between base & acid hydrolysis?

A

base hydrolysis is irreversible since anion is resistant to attack by nucleophiles

22
Q

what is the functional group of an acyl chloride?

A

-COCl

23
Q

what is the relative reactivity of an acyl chloride compared to its carboxylic acid? why?

A

much more reactive
- Cl is a good leaving group

24
Q

in which 4 ways could an acyl chloride react?

A
  • H2O
  • alcohols
  • NH3
  • primary amines
25
Q

what are the reagents, conditions and products of reacting acyl chlorides with H2O?

A

reagents - H2O
conditions - room temp
products - carboxylic acid + HCl gas

26
Q

what are the reagents, conditions and products of reacting acyl chlorides with alcohols?

A

reagents - alcohols
conditions - room temp
products - ester + HCl gas

27
Q

what are the reagents, conditions and products of reacting acyl chlorides with NH3?

A

reagents - NH3
conditions - room temp
products - primary amide + NH4Cl

28
Q

what are the reagents, conditions and products of reacting acyl chlorides with primary amines?

A

reagents - primary amine
conditions - room temp
products - n-linked amide + HCl gas

29
Q

why is reacting acyl chlorides with alcohols a better way of making esters?

A

reaction is not reversible & quicker

30
Q

what is the functional group of a primary amide?

A

-CONH2

31
Q

what is the difference between an amide & an amine?

A

amide has an oxygen bonded to the same carbon

32
Q

how are polyesters formed by condensation polymerisation?

A

1- dicarboxylic acid + diol -> polyester + H2O
2- diacyl chloride + diol -> polyester + HCl
3- carboxylic acid + alcohol -> ester + H2O (in equilibrium mixture)