OCR A2 Chemistry impurity question help

Watch
WilliamSlim
Badges: 3
Rep:
?
#1
Report Thread starter 7 years ago
#1
delete
0
reply
Pigster
Badges: 20
Rep:
?
#2
Report 7 years ago
#2
The NH2 end can form an amide. The OH end can form an ester.
0
reply
WilliamSlim
Badges: 3
Rep:
?
#3
Report Thread starter 7 years ago
#3
delete
0
reply
Pigster
Badges: 20
Rep:
?
#4
Report 7 years ago
#4
The equation you wrote showing the formation of paracetamol involves the NH2 end forming an amine link. The other end has an OH group. In unit 4.1.3 you (should have) learnt that OH groups can esterify with acid anhydrides. Try doing adding the ester linkage to paracetamol, then seeing what the overall molecular formula of the product is.

In 4.1.4 you should have learnt about nucleophilic substitution of a halogenoalkane by ammonia (although most teachers do it in 2.2.2). Essentially, the lone pair on the N in NH3 attacks the d+ C next to the Cl. The 2-aminocarboxylate you have drawn STILL has a lone pair on it, so can attack a second 2-chloropropanoic acid by nucleophilic substitution, creating a secondary amine.
0
reply
WilliamSlim
Badges: 3
Rep:
?
#5
Report Thread starter 7 years ago
#5
delete
0
reply
Pigster
Badges: 20
Rep:
?
#6
Report 7 years ago
#6
If you plan to make paracetamol and you make the compound with the ester linkage as well, then since the ester linked compound is not the chemical you want it is an impurity - your paracetamol is not pure.

Ditto with the primary amine containing come secondary amine.
0
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Back
to top
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

Do you think receiving Teacher Assessed Grades will impact your future?

I'm worried it will negatively impact me getting into university/college (16)
39.02%
I'm worried that I’m not academically prepared for the next stage in my educational journey (4)
9.76%
I'm worried it will impact my future career (2)
4.88%
I'm worried that my grades will be seen as ‘lesser’ because I didn’t take exams (9)
21.95%
I don’t think that receiving these grades will impact my future (5)
12.2%
I think that receiving these grades will affect me in another way (let us know in the discussion!) (5)
12.2%

Watched Threads

View All
Latest
My Feed