Chapter 26 - Carbonyls and Carboxylic compounds Flashcards

1
Q

Define carbonyl compound

A

A compound containing the C=O functional group

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2
Q

Give 2 examples of a carbonyl compound

A

Aldehydes

Ketones

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3
Q

What is the suffix for an aldehyde?

A

-Al

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4
Q

What is the suffix for a ketone?

A

-One

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5
Q

Where is the C=O located in an aldehyde?

A

At the end of the chain

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6
Q

Where is the C=O located in a ketone

A

In the middle of a chain

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7
Q

What are carbonyls said to be in they contain a benzene ring?

A

Aromatic

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8
Q

What are carbonyls said to be if they do not contain a benzene ring?

A

Aliphatic

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9
Q

What is the simplest aromatic aldehyde called?

A

benzaldehyde

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10
Q

What is the simplest aromatic ketone called

A

Phenylethanone

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11
Q

What happens when a primary alcohol is oxidised under distillation?

A

It becomes an aldehyde

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12
Q

What happens when a primary alcohol is oxidised under reflux?

A

It becomes a carboxylic acid

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13
Q

What happens when a secondary alcohol is oxidised under reflux?

A

It becomes a ketone

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14
Q

What happens when a tertiary alcohol is oxidised under distillation or reflux?

A

Nothing as they are resistant to oxidation

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15
Q

What are alcohols reacted with to oxidise?

A

Acidified dichromate

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16
Q

Define reflux

A

The continual boiling and condensing of a reaction mixture to ensure that a reaction takes place without the contents of the flask boiling dry

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17
Q

What can an aldehyde be reduced to?

A

a primary alcohol

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18
Q

What can a ketone be reduced to?

A

a secondary alcohol

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19
Q

What is the reducing agent used for reduction of carbonyl compounds?

A

NaBH4

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20
Q

What are the conditions for the reduction of carbonyl compounds?

A

Warm and a H20 solvent

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21
Q

How can NaBH4 be represented in an equation showing the reduction of an alcohol?

A

[H]

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22
Q

How many [H] are required to reduce an aldehyde or a ketone to an alcohol?

A

2[H]

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23
Q

What is the mechanism used to reduce a carbonyl to an alcohol?

A

Nucleophilic addition

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24
Q

Why is it nucleophilic?

A

Because NaBH4 reacts with a carbonyl to produce an alcohol it releases a H- ion in solution, which is a nucleophile as it is attracted to positively charged areas

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25
Q

Define nucleophile

A

an atom or group of atoms which is attracted to an electron deficient centre, where it donates a pair of e- to form a new covalent bond

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26
Q

Define addition

A

a reaction in which a reactant is added to an unsaturated molecule to make a saturated molecule

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27
Q

What mechanisms are required to make a hydroxynitrile from a carbonyl?

A

nucleophilic addition

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28
Q

What reagent is used to make a hydroxynitrile?

A

HCN

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29
Q

What ions does the reagent used to make a hydroxynitrile have?

A

CN-

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30
Q

Which atom in a carbonyl will CN- be attracted to? Why?

A

C, because it is partially positive

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31
Q

Which bond breaks when CN- is attracted to C? What happens after that?

A

C=O breaks, C-O forms and C-CN forms and O-H forms

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32
Q

Explain the process of reduction of an alcohol by NaBH4?

A

The C=O bond in the carbonyl is polar, with the C being partially positive and the O being partially negative.
The hydride ion from NaBH4 is attracted to the C as it is a nucleophile, and forms a covalent bond with it using the lone pair.
One of the bonds in the C=O breaks and the pair of electrons goes to the O atom, so the O atom becomes negatively charged
The O atom uses the lone pair to form a bond with the H of a H20 (from the water solvent) and the OH bond in the water molecule breaks, forming an alcohol and an OH- ion.

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33
Q

What can be used to detect the presence of a carbonyl group in an organic compound?

A

2,4 - dinitrophenylhydrazine

34
Q

What colour change is there when using 2,4 - dinitrophenylhydrazine?

A

Colourless to orange/yellow precipitate

35
Q

What doesnt 2,4- dinitrophenylhydrazine detect the presence of?

A

Carboxylic acids or esters

36
Q

What is the name of the precipitate formed when 2,4-dinitrophenylhydrazine reacts with a carbonyl?

A

2,4 - dinitrophenylhydrazone derivative

37
Q

What can the 2,4 - dinitrophenylhydrazone derivative be used to identify?

A

Whether the carbonyl is a ketone/ aldehyde

38
Q

How can the 2,4 - dinitrophenylhydrazone derivative be used to identify whether the carbonyl is a ketone or aldehyde?

A
  1. the 2,4 DNP derivative is purified by recyrstallisation
  2. the melting point is determined
  3. this is compared to a database to identify whether it is an aldehyde/ ketone
39
Q

What reagent can be used to identify only an aldehyde?

A

Tollen’s reagent

40
Q

What is the positive presence of an aldehyde using Tollen’s presence?

A

colour change from colourless –> formation of a silver mirror

41
Q

What is Tollen’s reagent made of?

A

Ammoniacal silver nitrate

42
Q

What is the method for using Tollen’s reagent?

A
  1. add 2cm3 of sample to a test tube
  2. add 2cm3 of tollens reagent to the test tube
  3. Heat in water bath
43
Q

What is the functional group of a carboxylic acid?

A

COOH

44
Q

What happens to solubility when chain length decreases? Why?

A

It increases, because the solubility is due to hydrogen bonding, and the hydrocarbon section of the carboxylic acid is non-polar, and therefore will not bond to water molecules, so the shorter the hydrocarbon section the more likely the acid is to dissolve

45
Q

What is solubility of carboxylic acids?

A

The tendency of a carboxylic acids to dissolve in water

46
Q

Are carboxylic acids weak or strong acids? why?

A

Weak because only a small proportion of acid molecules will dissociate and the position of equilibrium lies well to the left and therefore produces more acid molecules than hydrogen protons

47
Q

What type of salt is formed from a carboxylic acid?

A

A Carboxylate salt

48
Q

What is the difference between a carboxylate salt and a carboxylic acid?

A

Carboxylate salts have had the H atom on the OH replaced by a negatively charged atom

49
Q

What is the name of a methanoic acid salt?

A

methanolate

50
Q

What is the name of an ethanoic acid salt?

A

ethanoate

51
Q

What is the name of an propanoic acid salt?

A

propanoate

52
Q

Carboxylic acid + metal –>

A

Salt + hydrogen

53
Q

Carboxylic acid + carbonate –>

A

salt + carbon dioxide + water

54
Q

Acid + base –>

A

Salt + water

55
Q

What is the functional group of an ester?

A

COOC

56
Q

Alcohol + carboxylic acid –>

A

Ester + water

57
Q

Alcohol + acid anhydrides –>

A

ester + carboxylic acid

58
Q

Ester + alkaline –>

A

Alcohol + carboxylate salt

59
Q

What is esterification?

A

the formation of an ester from alcohol and a carboxylic acid

60
Q

What is an acid anhydride?

A

A molecule formed from 2 acid molecules, which have lost a molecule of water

61
Q

What conditions are required for esterification?

A

Conc H2SO4, reflux, heat

62
Q

What conditions are required for hydrolysis of an ester using alkaline conditions?

A

NaOH or KOH, heat and reflux

63
Q

What conditions are required for hydrolysis of an ester under standard conditions?

A

Dilute H2SO4, reflux, heat

64
Q

Write a general equation for the hydrolysis of an ester under standard conditions

A

ester + water –> carboxylic acid + alcohol

65
Q

Write a general equation for the hydrolysis of an ester under alkaline conditions

A

ester + alkaline –> alcohol + carboxylate salt

66
Q

Write a general equation for the formation of an ester under standard conditions

A

carboxylic acid + alcohol –> ester + water

67
Q

Write a general equation for the formation of an ester using an acid anhydride

A

Alcohol + acid anhydride –> ester + carboxylic acid

68
Q

What is the functional group of an acyl chloride ?

A

COCl

69
Q

Write an equation for the preparation of an acyl chloride

A

Carboxylic acid + SOCl2 –> acyl chloride + SO2 + HCl

70
Q

Acyl chloride + alcohol –>

A

Ester + HCl

71
Q

Acyl chloride + 2NH3 –>

A

primary amide + NH4CL

72
Q

Write an equation of the formation of a primary amide

A

Acyl chloride + 2NH3 –> primary amide + NH4Cl

73
Q

Write an equation of the formation of a secondary amide

A

Acyl chloride + primary amide —> secondary amide + NH4Cl

74
Q

Acyl chloride + primary amide —>

A

secondary amide + NH4Cl

75
Q

Acyl chloride + phenol –>

A

phenyl ester + HCl

76
Q

Write the equation for the formation of a phenyl ester

A

Acyl chloride + phenol –> phenyl ester + HCl

77
Q

Acyl chloride + water –>

A

Carboxylic acid + HCl

78
Q

What is the functional group of a primary amide?

A

CONH2

79
Q

What does a primary amide react similarly to?

A

A carboxylic ester

80
Q

What is the functional group of a secondary amide?

A

CONHCH3