O Chem question

[ToothFairy423]

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Hi Guys,
was wondering if I could get help on this question.

CH3CH2-O-C=O OH + CH3CH2OH -------> (h+)


Kaplan says the answer is CH3CH2OCOCH2CH3

I was thinking that the carbonyl group still stays on there, as the alcohol acts as a nucleophile and attaches to the carbonyl group, the OH gets protonated and acts as a leaving group, forming CH3CH2-O-C=O O-CH2CH3


Basically I am getting an extra Oxygen in the molecular formula than Kaplan is.
Any ideas? Hopefully you can interprety my formulas I have tried to draw out somehow.

Thanks!

 

[DrTacoElf]

wow this is hard to read but here is what happens (i think). The H+ should protonate the alcohol functional group on the main molecule and the ethanol will nucelophilically attack the carbonyl group on the main molecule via SN2 and the leaving group will be water (protonated OH).

So in the end you should have

H3C-CH2-O-C(=O)-O-CH2-CH3

 

[luder98]

Hi Guys,
was wondering if I could get help on this question.

CH3CH2-O-C=O OH + CH3CH2OH -------> (h+)


Kaplan says the answer is CH3CH2OCOCH2CH3

I was thinking that the carbonyl group still stays on there, as the alcohol acts as a nucleophile and attaches to the carbonyl group, the OH gets protonated and acts as a leaving group, forming CH3CH2-O-C=O O-CH2CH3


Basically I am getting an extra Oxygen in the molecular formula than Kaplan is.
Any ideas? Hopefully you can interprety my formulas I have tried to draw out somehow.

Thanks!

Is there anything else besides H+? Under certain circumstances, you can cleave off the O=. If H+ is the only reagent, I agree with your result. I also found another error in Kaplan solution in subject test 5. Where is this question? I don't recall seeing it.

 

[ToothFairy423]

wow this is hard to read but here is what happens (i think). The H+ should protonate the alcohol functional group on the main molecule and the ethanol will nucelophilically attack the carbonyl group on the main molecule via SN2 and the leaving group will be water (protonated OH).

So in the end you should have

H3C-CH2-O-C(=O)-O-CH2-CH3

Taco, my thoughts EXACTLY. wierd. maybe kaplan is wrong then? their answer is missing the Oxygen from the ethanol that attacks.

 

[ToothFairy423]

Is there anything else besides H+? Under certain circumstances, you can cleave off the O=. If H+ is the only reagent, I agree with your result. I also found another error in Kaplan solution in subject test 5. Where is this question? I don't recall seeing it.

This question was on one of their online DAT exam. if you actually took the class, you would have seen it on your online syllabus. Did you take the class or just study their materials? If you did take the class, did you ever take any of their exams they had? the RC SUCKS, i feel that the questions are so misleading and its really hard to find the answers in the passages.

 

[luder98]

No wonder why I didn't see it! I registered for the online class for I didnot have time to come to class and I prefer studying on my own. I never got to take those online exams. I only had time to study the material and do the subject tests and bio midterm. I did not study for RC for I know that it will not help me (I know me). I went over one tsp passage to get an idea what I will face. And that was it. I got 16 if you want to know 😀