OCR Chemistry A F324 Rings, Polymers and Analysis Tue 19 June 2012

instead of using etahnoic acid youre using ethanoic anhydride. Now the reaction with the propan2ol produces the exact same ester that you would get with ethanoic acid and propan2ol yet with the anhydride you get ester+acid instead of ester+water. This is because of the anhydride, look at the structure of the anhydride, (ch3co)2 o, theres 2 molecules of ethanoic acid joined together (with the elimination of water) so therefore when you react it with the alcohol, one of the acid reacts and the other one just reforms. Does that help in any way?

still the paper was not that easyyyy there were some tricky parts to it like the cyclic dimer

As you can see, there is no water formed.

is this right

CH3COOCH2CH(OH)CH3?

We did this paper in class and to be fair that was the only tricky question. Every other question was do-able. There are bound to be questions which will be 1 or 2 marks which are really though and my teacher gave us some helpful advice, don't waste your time if it's only a 1 or 2 marker! OCR like throwing these in every exam. Apart form that every question was regurgitated and repeated in past papers. The NMR question at the end was pretty straight forward aswell

Do we need to memorise the monomers required to form Terylene, Kevlar, Nylon-6,6 and so on? In past exam papers they've always given us the monomers needed.

I'm not sure and I need clarification of this aswell. I'm sure they'll give you the individual monomers but I need reassurance that this is the case.

Not quite, it's CH3COOCH(CH3)2

ohhh right now i get it easy thanks

Struggling on the (b) side to this Q. Hoping you can help, been stuck for ages. Please explain steps. Thanks

no worries you know on june 2012 question 5b part 2, about the structure of the compound with c4h11no2, how did you do that one? I dont get it

i dont get after the O how you got the CH(CH3)2?

Struggling on the (b) side to this Q. Hoping you can help, been stuck for ages. Please explain steps. Thanks

you mean tomorrows paper JUNE 2012?

how would cyclohexane-1,4-diol show up on an NMR? it says 3 peaks and area of 1:1:4. but whyyyy

lmaoo sorry, i meant june 2010 haha

http://pdf.ocr.org.uk/download/kd/ocr_9910_kd_gce_spec.pdf? page 46

Ok so the structure of propan-2-ol is CH3CH(OH)CH3. When it reacts with the ethanoic anhydride the OH group becomes an O bonded to the ethanoic part. So it has a central C bonded to one H, one O and two CH3 groups

Ahh thanks for that! Relieved! x