Chaoter 26.4 Derrivates Of Carbixykic Acids

Question 1

What is a derivation of a carboxylic acid or a compound in general

What is common between all

Answer 1

This is any compound that can be hydrolysed (add OH) to form that again, so essentially a cabrixykic acid derivative is one that came from it in the first place

2) RCO, and OH PART IS REPLACED EACH TIME

Question 2

What are the 4 carbixykic acid derivatives we need to know

What’s common between all

Answer 2

• ester = alcohol and carbixykic acid
• acid anhydride = two carboxylic acids
• acyl chloride = cabroxykic acid and (thionyl chloride?)
• amides = carboxylic acid and amines

Again rcO same only thing different is where OH was at

Question 3

Esters
- how are they made
- catalyst
- how names

What reaction called? What product

Answer 3

Alcohol and cabrixykic acid in presence of sulphuric acid catalyst

• named as alcohol then cabrixykic aicd (identity these then draw)

This is a CONDENSATION REACTION which forms either water or hcl (if acyl chloride used )

Question 4

What is a condensation reaction definition ?

Answer 4

Addition reaction followed by elimination,

Forming a big product and a small one (normally water or hcl)

Question 5

Basic properties of ester to confirm?

Answer 5

Typically colourless
- smell like fruits
- actually in some too

Question 6

How to do esterificsrion reaction in lab
(What key thing to do once made)

Answer 6

Add the alcohol and acid
2) add catalyst
3) place in boiling tube at 80° for 5 minutes (or water bath)
4) then neutralise in aqueous sodium Carbonate ti get rid if the remaining sukfuric acid or any other cabrixykic acid (we did this remember), should see effervescence

5) now have some oily drips of ester - should be fruity smell to identity

Question 7

How can esters be hydrolysed to go back to alcohol and carboxylic acid?

Answer 7

Acid hydrolysis
Alkaline hydrolysis

Question 8

How to do acid hydrolysis of esters
What reactant , conditions and catalyst

Is this reversible or irreversible?

Answer 8

Reverse process of esterifcsrion

• reflux and with DILUTE AQEUOUS ACID
• add water, and this reforms the two as water was lost

= water, reflux and aqeuous dilute acid, lit reverse

2) REVERSIBLE - think about it it’s just reverse if edterifation, same can happen again

Question 9

Alkaline hydrolysis of esterificsrion

Answer 9

This uses aqeuous HYDROXIDE IONS

• forms the alcohol fully but an ion for the cabrixykic acid
• if the source of hydroxide ions was NaOH in the first place, now becomes Na+ in the carboxylic acid so doesn’t fully bring it back but yeah
  = sodium carboxylate

Question 10

Hydrolysis summary

Answer 10

Acid = water, reflux, dilute aqeuous acid, reversible

Alkaline = source of hydroxide ions (NaOH), irreversible , forms alcohol and sodium carboxylate salt , IRREVERSIBLE
Aka saponification

Question 11

How to name acyl chlorides

How to name acid anhydrides

Answer 11

It’s just the cabrixykic acid and now oyl chloride

So propanoic acid = propanoyl chloride

2) acid anhydrides are made from two equal acids losing water
- this if they both came from Ethan oil acid , = ethanoic anhydride (without water )

And the displayed is brackets 2 and o

Question 12

How are acyl chlorides even made!
What is the key REACTANT
what is produced?
So where should this take place

Answer 12

From parent chain carboxylic acid reacted with THINOYL CHLORIDE (= SOCL2)

This reacts to form acyl chloride, so2 and hcl (as o from oh goes to so and h ti cl)

As a result this reaction should happen in a FUME CUPBOARD, because these gases evolved can be toxic!

Question 13

What reactions can acyl chlorides basically take part in

And why is it preferred to be used over carboxylic acids?

Answer 13

I’m any reaction a carboxylic can take in, because cl like oh is removed

BUT MORE REACTIVE THEN CARBOXYLIC ACIDS, so can be used more readily

Question 14

What reactions can it do

Answer 14

1) like carbox, with alcohol = ester and HCL
2) unlike carbox cuz too unresvrjve, with Phenol to form ester and HCl
3) with water to form a carboxylic acid and HCl
4) reaction with ammonia and amines to form different amides .

Question 15

1) acyl chlrodie with alcohol?

Answer 15

Condensation = ester and hcl

Question 16

2) ache chrlodie with phenol?

Answer 16

Condensation , ester and hcl

Only works because Ayckbourn chloride MORE REACTIVE THEN CARBOXYKIC ACID !

Question 17

3) acyl chrloide with water to from carboxylic side?

Answer 17

Again forms hcl

This is a violent reaction

Question 18

4) acyl chrlode with amines / ammonia to form amides?
Ammonia

Answer 18

1) ammonia and amines act as nucleophiles to react with partially positive cabron.
- first ammonia reacts to form primary amides and ammonium chloride

It’s acyl chrlodie and 2 ammonia = amide primary and ammonium chloride

At any point only one nh2 is removed

Question 19

4) acyl chlroide with amines?

Answer 19

Can react with a primary amine to form a SECONDARY AMIDE
again achy chrlode and 2 primary amines to from a secondary amide and a r group ammonium chloride ion

Question 20

Amide bond

Answer 20

Is between carboxylic and now nH so CONH bond

Question 21

Naming amines

Answer 21

Primary alll follow r group formula

Ammonia I guess 0 amine, so firms primary amide
But the primary amide then forms secondary amide, way of remembering

Question 22

How to name amides

Answer 22

Amide because the suffix like carboxykic acid, then found carbons

However if attached to the N any r group = N-methyl or whatever, showing this attached to the N, and then the carbon chain amide!

Question 23

Ions produced?

Answer 23

Always an ammonium chloride ion of some sort,

Might be an r group attached to it

Question 24

Remember in reaction with a primary amide, what is attached to the acyl chrloide in place of the chloride?

Answer 24

The whole chain except for one hydrogen! This is then given to the ammonium chrlodie ion making nh3 and thus positive! Which attaches to the negative chlroide ion

Question 25

What reactions do acid anhydrides take part in? And why

Answer 25

More reactive than cabroxykic acids, but less reactive than acyl chrlodies, thus sometimes preferred to use this as acyl too reactive and also can produce some dodgy gases

Reacts with everything like acyl chrlodie but differently, same with aclholhs to form esters, etc phenols , water to form carboxylic acids (obviously), amines and ammonia still alkaline the same

. Sometimes a cabroxykic acid is formed