How ?

describe this?

(edited 3 years ago)

Do you have the molecular formula for the compound? Any other information such as class etc.? Do you have any other spectra like MS or NMR?

Reply 2

KarolL

Original post by TheKitty.x

this is a lab report to do from a Preparation and Purification of 2-chloro-2-methylpropane. But I didn't do this in the lab cuz of lockdown, therefore I only watched a video on youtube.

This was the result, which was provided as an IR Spectrum.
18.2mL of tert-butyl-chloride were obtained where the yield was 49% (as on the video).

Can you please help me to answer these questions? I'm so lost..

1) Calculate your percentage yield based on data provided to you.
2) Does this IR indicate that the product is tert-butyl chloride (2-chloro-2-methylpropane)?
3)What is the evidence in the IR spectrum for this?
4) Does the IR spectrum indicate any impurities? What is the evidence for this?
5) A 1H-nmr spectrum for the product is shown below. Why is there only one peak in the spectrum, (there are 9 H atoms in t-butyl chloride)?

I am not sure if it is possible to calculate the yield using exclusively the data from the IR. I know NMR might be useful (or qNMR rather), but unfortunately someone with more knowledge than me would have to answer that I am afraid.
Check this for IR spectrum of pure 2-chloro-2-methylpropane:
https://webbook.nist.gov/cgi/cbook.cgi?ID=C507200&Type=IR-SPEC&Index=1#IR-SPEC
You can also analyse the IR spectrum using signal tables like this one: https://www.sigmaaldrich.com/technical-documents/articles/biology/ir-spectrum-table.html
In regards to the NMR the product gives only one signal, because there are no vicinal hydrogen atoms, so there is no splitting pattern and all hydrogen atoms in a molecule have the same "neighbourhood", so they all give the same signal.