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Chemistry :) > 6.1 Aromatic Compounds, Carbonyls and Acids (completed) > Flashcards

6.1 Aromatic Compounds, Carbonyls and Acids (completed) Flashcards

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1
Q

What is the carbonyl group?

A

Carbon oxygen double bond

C=O

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2
Q

What are examples of carbonyl compounds?

A

Aldehydes (from primary alcohols)

Ketones (from secondary alcohols)

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3
Q

How do you produce the carbonyl compounds?

A

Acidified potassium dichromate [O]

Aldehyde distill primary alcohol
Ketone reflux secondary alcohol
Carboxylic acid reflux primary alcohol

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4
Q

What is the test for aldehydes?

A 
Tollen’s reagant 
Heat in hot water bath
Silver compund is reduced to silver metal
Forms a silver mirror 
Aldehyde is reduced to carboxylic acid
Also NH4+ ions
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5
Q

What is the test for aldehydes and ketones?

A

2,4-DNPH Brady’s Reagent

Produce an orange precipitate

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6
Q

How can you find which carbonyl compound has tested positive with Brady’s reagent?

A

Purify and recrystallise and precipitate

Find its’s melting point and compare with known values

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7
Q

What is the reduction of aldehydes and ketones?

A

Nucleophilic addition to produce alcohols

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8
Q

How do you reduce aldehyde’s and ketones?

A 
With NaBH4 (sodium tetrahydridoborate) 
To produce a hydride ion H- with a lone pair
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9
Q

What is the first step in the mechanism of nucleophillic addition?

A

δ+ and δ- on C=O bond
Curly arrow from hydride ion lone pair to carbon
Curly arrow from C=O bond to oxygen

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10
Q

What is the second step in the mechanism of nucleophillic addition?

A

Lone pair and negative charge on oxygen
δ+ and δ- on H and O in water
Curly arrow from lone oxygen pair to hydrogen in H2O
Curly arrow from O-H bond to oxygen

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11
Q

What is the third step in the mechanism of nucleophillic addition?

A

Alcohol produced and OH- ion

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12
Q

What are the reagents and conditions needed to produce a nitrile from a carbonyl?

A

CN- ions
In dilute acid e.g. H2SO4
Nucleophilic addition

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13
Q

What does adding a cyanide ion do to the carbon chain?

A

Increases the length

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14
Q

What is the molecular formula of benzene?

A

C6H6

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15
Q

What was kekulé’s model for benzene?

A

Cyclic
Planar
Alternating double and single bonds

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16
Q

What were the problems with Kekulé’s model?

A

All the bonds are same length BUT in Kekulé’s model the C=C bonds will be shorter
Benzene does not behave like an alkene with C=C bonds as it does not easily undergo addition reactions
The enthalpy is not as exothermic as predicted (it’s too stable)

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17
Q

What is the updated benzene model?

A

π electrons are in delocalised rings of overlapping p orbitals above and below the carbon ring
Planar ring
120° bond angle
Carbon bonds are all the same length

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18
Q

Describe the mechanism for electrophilic substitution

A

Curly arrow from benzene ring to Electrophile (E+)

Half ring with + inside
H and E bonded to carbon ring
Curly arrow from H bond to +

Electrophile bonded to carbon ring
H+ as other product

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19
Q

What are the reagants of the nitration of benzene?

A

Conc. nitric acid
Conc. sulphuric acid (catalyst)
Reflux
55°c

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20
Q

What is the nitration of benzene used for?

A

Explosives, dyes

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21
Q

How is sulphuric acid regenerated as a catalyst in the nitration of benzene?

A

H2SO4 + HNO3 → HSO4- + NO2+ + H2O
NO2+ is electrophile which generates H+ inmechanism
H+ + HSO4- → H2SO4

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22
Q

What happens if you added bromine water to benzene?

A

Nothing happens

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23
Q

How does the halogenation of benzene occur?

A

By using a halogen and a halogen carrier catalyst
e.g. Fe, FeCl3, AlCl3
Reflux

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24
Q

How does the halogen carrier catalyst produce a halogen electrophile?
(use chlorine and AlCl3)

A

Cl2 + AlCl3 → AlCl4- + Cl+
it’s regenerated so is a catalyst
AlCl4- + H+ → AlCl3 + HCl

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25
Q

What are the two types of Friedal Crafts Reactions?

A

Alkylation - substitution with an alkane R e.g. CH3Cl

Acylation - substitution with a carbonyl R-CO e.g. CH3COCl

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26
Q

What are the Friedal Crafts Reactions?

A

Formation of a C-C bond to an aromatic ring

27
Q

What are the reagants and conditions needed for alkylation?

A

Alkyl Chloride - RCl
Halogen carrier catalyst e.g. AlCl3
Anhydrous conditions
Electrophilic Substitution Mechanism

28
Q

What are the reagants and conditions needed for acylation?

A

C=O RCOCl
Halogen carrier catalyst e.g. AlCl3
Anhydrous conditions
Electrophilic Substitution Mechanism

29
Q

Why does the hydrogenation of benzene have a higher value?

A

It’s resistant to hydrogenation becuase it destroys the stable delocalised electron system giving it a high activation energy

30
Q

What is phenol?

A

C6H5OH

A very weak acid with an OH group attached directly to the benzene ring

31
Q

Why is phenol solid at room temperature?

A

It can form hydrogen bonds which require more energy to break

It’s an almost colourless cyrstaline solid

32
Q

What does phenol react with?

A

Metals
Hydroxide
NOT carbonates (it’s too weak an acid)

33
Q

Why can phenol react with bromine without a halogen carrier?

A

The lone electron pair on OH
is drawn into the deloclaised benzene ring
increases the electron density of the ring
activating it
able to induce a dipole on Bromine

34
Q

What is the reaction of phenol with sodium and sodium hydroxide?

A 
Produces Sodium Phenoxide C6H5O-Na+
and H2O (NaOH)
or H2 (2Na)
35
Q

How do 2- 4- directing groups affect the reactivity of the ring when activating it?

A

Increase it by donating an electron onto the ring

36
Q

How do 3- directing groups affect the reactivity of the ring when activating it?

A

Decrease it by withdrawing an electron from the ring

37
Q

What are examples of 2- 4- directing groups?

A

OH

NH2

38
Q

What are examples of 3- directing groups?

A

NO2

39
Q

What are the uses of phenols?

A

TCP
Adhesives
Compact discs

40
Q

What are nitriles used to make?

A

Amines

41
Q

What is the addition of HCN to a carbonyl?

A

Nucleophilic addition

42
Q

What is the functional group of carboxylic acids?

A

-COOH

43
Q

Are carboxylic acids soluble and if so why?

A

Yes, they have hydrogen bonding

44
Q

How does the solubility change as the chain length increases?

A

Decreases as a result of the increasing nonpolar chain which can’t interact with water molecules

45
Q

What is the reaction of a metal and a carboxylic acid?

A

Salt e.g. magnesium ethanoate

Hydrogen 

46
Q

What is the reaction of a hydroxide and a carboxylic acid?

A

Salt e.g. potassium propanoate

Water

47
Q

What is the reaction of a carbonate and a carboxylic acid?

A

Salt e.g. Calcium methanoate
Water
CO2

48
Q

What are the uses of esters?

A

Perfumes, flavourings, essential oils, adhesives

49
Q

What is the conditions needed for esterification?

A

Strong catalyst

e.g. concentrated sulphuric acid

50
Q

What is the reaction of an acid and alcohol?

A

RCOOH + R’OH → RCOOR’ + H2O

51
Q

Name these esters

1) CH3CH2COOCH3
2) HCOOCH2CH3
3) CH3OOCCH3

A

1) Methyl Propanoate
2) Ethyl Methanoate
3) Methyl Ethanoate

52
Q

What is the reaction between an acid anhydride and an alcohol?

A

Acid anhydride + alcohol → Ester + carboxylic acid

53
Q

How can Esters be hydrolysed?

A

Under acidic or alkaline conditions

Reflux

54
Q

What is hydrolysis for esters with acidic conditions?

A

Produces a carboxylic acid and alcohol
Requires reflux
Same conditions as esterification so dynamic equilibrium is formed

55
Q

What is hydrolysis for esters with alkaline conditions?

A

Produces a salt E.g. sodium ethanoate

And alcohol

56
Q

What is the acyl group?

A

RCOR’

57
Q

What is an acyl chloride?

A

RCOCl

58
Q

How do you produce an acyl chloride?

A

Carboxylic acid + Thionyl chloride (SOCl2) → Acyl Chloride + SO2 + H2O

59
Q

What is the reaction of an acyl chloride and water?

A

Produces carboxylic acid and HCl

60
Q

What do acyl chlorides react with?

A

Nucleophiles

61
Q

What is the reaction of an acyl chloride and alcohol?

A

Ester + HCl

62
Q

What is the reaction of an acyl chloride and ammonia?

A

Primary amide

63
Q

What is the reaction of an acyl chloride and primary amide? 

A

Secondary amide

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