Carboxylic acid and derivatives

  • Created by: Hindleyc
  • Created on: 04-12-18 16:28
Name?
Ending -oic acid no number necessary for acid group as on end of chain
1 of 53
Where does numbering start from?
Carboxylic acid end
2 of 53
What if carboxylic acids groups on both ends of the chain?
-dioic acid with e in name
3 of 53
What is their acidity like?
Weak acids in water and only slightly dissociate
4 of 53
What are they, however, strong enough to do?
Displace CO2 from carbonates
5 of 53
EQN?
CH3CO2H(aq) =(reversible) CH3CO2^- (aq)+ H^+ (aq)
6 of 53
Solubility?
Smaller carboxylic acids (up to C4) dissolve in water in all proportions
7 of 53
What happens after this?
Solubility rapidly reduces
8 of 53
Why do smaller ones dissolve?
Can hydrogen bond to water molecules (slightly negative o on C=O and +ve H on h2o)
9 of 53
How are the carboxylic acid salts stabilised?
By delocalisation which therefore makes it more likely
10 of 53
What does the delocalised ion have?
Equal C-O bond lengths so if it didn't occur the C=O bond would be shorter than C-O bond
11 of 53
What has the Pi charge cloud done
delocalised and spread out- delocalisation makes more stable and therefore more likely to form
12 of 53
What does strength of carboxylic acid depend on?
Stability of anions formed, less tech large delocalised, less stable ion, weaker acid
13 of 53
Inc chain length?
Pushes e- density on the COO- ion making it more negative and less stable making acid less strong
14 of 53
Propanoic vs ethanoic acidity?
ethanoic stronger
15 of 53
Electronegative chlorine atom..
Withdraw electron density form COO- ion making it less negative and more stable making acid more strong
16 of 53
Chloroethanoic acid vs ethanoic acid acidity>
Chloro more acidic
17 of 53
What can carboxylic acids form salts with?
Metals alkalis and carbonates
18 of 53
Acid + reactive metal=
Carboxylate salt and hydrogen
19 of 53
Acid + alkali =
Salt and water
20 of 53
Acid + metal carbonate =
salt + water + co2
21 of 53
Acid + metal oxide=
Salt + water
22 of 53
What can the effervescence caused by production of CO2 with carboxylic acids and solid sodium carbonate or aqueous sodium hydrogen carbonate be used for?
Functional group test for carboxylic acids
23 of 53
Oxidation of methanoic acid?
Carboxylic acids cannot be oxidised by using oxidising agents but methanoic acid is an exception as its structure has effectively an aldehyde group
24 of 53
What does this form +[O]
Carobnic acid that can decompose to give co2
25 of 53
What is esterification
When carboxylic acids react with alcohol in the presence of a strong acid catalyst to form esters and water
26 of 53
eg name of ester
Methyl propanate
27 of 53
Where does -yl bit come from
alcohol that formed it and is next to single bonded oxygen (alchohol then cooh)
28 of 53
Bit ending -anoate?
COOh and includes the C in the C=O bond
29 of 53
What is this rxn usually
Condensation producing water but not always
30 of 53
What is the rxn\?
Reversible
31 of 53
What else is it?
Slow, needs heating under reflux (often for several hours or days) low yields and acid catalyst needed
32 of 53
What acid catalyst?
H2SO4
33 of 53
Uses as sweet smelling compounds?
Perfumes and flavourings (toxic, non soluble volatile and not react with water
34 of 53
Solvents?
For polar organic substances eg glue and printing inks
35 of 53
Although polar, what don't they do
Hydrogen bond as no H bonded to a highly electronegative atom- have lower bp than H bonded carboxylic acids and almost insoluble in water
36 of 53
Plasticisers for polymers?
Often have limited flexibility bc can't move over each other so incorporating some plasticisers in polymer allows chain to move more easily and polymer can become more flexible
37 of 53
Overall uses
Food, perfume industries, solvents and plasticisers
38 of 53
how can esters be hydrolysed and split up?
by either heating with an acid or with sodium hydroxide
39 of 53
Reagents with acid
Dilute HCL
40 of 53
Conditions
Heat under reflux
41 of 53
What is this the reverse RXN of
Ester formation
42 of 53
What happens when ester hydrolysed?
Carboxylic acid and alcohol formed
43 of 53
eqn
Ester+ water (reversible with H+ on top) =carboxylic acid and alcohol
44 of 53
What does the carboxylic acid do?
reacts with water to reform OH- catalyst
45 of 53
What is this reaction
Reversible and doesn't give a good yield of products
46 of 53
Ester with Sodium hydroxide
Sodium salt and alcohol
47 of 53
Reagents
Dilute sodium hydroxide
48 of 53
Conditions
Heat under reflux
49 of 53
What does this rxn do
Go to completion
50 of 53
Ester + sodium hydroxide =
Sodium propanoate + methanol
51 of 53
What is the carboxylic acid salt product?
the anion of the carboxylic acid
52 of 53
What is the anion resistant to?
Attack by weak nucleophiles such as alcohol so rxn isn't reversible
53 of 53

Other cards in this set

Card 2

Front

Where does numbering start from?

Back

Carboxylic acid end

Card 3

Front

What if carboxylic acids groups on both ends of the chain?

Back

Preview of the front of card 3

Card 4

Front

What is their acidity like?

Back

Preview of the front of card 4

Card 5

Front

What are they, however, strong enough to do?

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all Reactions resources »