Chaoter 26.4 Derrivates Of Carbixykic Acids Flashcards
What is a derivation of a carboxylic acid or a compound in general
What is common between all
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
What are the 4 carbixykic acid derivatives we need to know
What’s common between all
- 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
Esters
- how are they made
- catalyst
- how names
What reaction called? What product
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 )
What is a condensation reaction definition ?
Addition reaction followed by elimination,
Forming a big product and a small one (normally water or hcl)
Basic properties of ester to confirm?
Typically colourless
- smell like fruits
- actually in some too
How to do esterificsrion reaction in lab
(What key thing to do once made)
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
How can esters be hydrolysed to go back to alcohol and carboxylic acid?
Acid hydrolysis
Alkaline hydrolysis
How to do acid hydrolysis of esters
What reactant , conditions and catalyst
Is this reversible or irreversible?
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
Alkaline hydrolysis of esterificsrion
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
Hydrolysis summary
Acid = water, reflux, dilute aqeuous acid, reversible
Alkaline = source of hydroxide ions (NaOH), irreversible , forms alcohol and sodium carboxylate salt , IRREVERSIBLE
Aka saponification
How to name acyl chlorides
How to name acid anhydrides
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
How are acyl chlorides even made!
What is the key REACTANT
what is produced?
So where should this take place
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!
What reactions can acyl chlorides basically take part in
And why is it preferred to be used over carboxylic acids?
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
What reactions can it do
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 .
1) acyl chlrodie with alcohol?
Condensation = ester and hcl
2) ache chrlodie with phenol?
Condensation , ester and hcl
Only works because Ayckbourn chloride MORE REACTIVE THEN CARBOXYKIC ACID !
3) acyl chrloide with water to from carboxylic side?
Again forms hcl
This is a violent reaction
4) acyl chrlode with amines / ammonia to form amides?
Ammonia
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
4) acyl chlroide with amines?
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
Amide bond
Is between carboxylic and now nH so CONH bond
Naming amines
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
How to name amides
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!
Ions produced?
Always an ammonium chloride ion of some sort,
Might be an r group attached to it
Remember in reaction with a primary amide, what is attached to the acyl chrloide in place of the chloride?
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
What reactions do acid anhydrides take part in? And why
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
