Question

2. (3 points) Based on the spectral data provided, (a) determine the structure of the unknown compound (C6H120; (b) assign ALL major peaks in the mass spec (if there is an molecular ion, base peak, alpha- cleavage or McLafferty rearrangement label the signal as such) and IR that led to the identification of your compound. L00 s000 4500 200e a00 sVENEPI 100 80 60- 40- 20 120 110 100 90 80 70 60 50 40 30 20 10 m/z Relative Intensity

Answer 1

Given MF: C6H1202: Degree of unsaturation = ((2C+2)+N-H-X)/2 = (14-12)/2 = 1 there is only one site of unsaturation. IR shows peak around 1745: means it is an ester. And that ester carboyl corrosponds to the one site of unsaturation. IR: 2940 and 2876: sp3 C-H stretching 1745: Ester C=O stretching 1470: CH3 rocking 1360: C-H bending 1250: ester C-O stretching Mass spectrum: M+ peak is very weak at 116. peaks at 85 and 87: Haioase → H₂C- H3C m/z=101 H2CH 0 3 H3C OH McLafferty Mol afferty i CH2 C HHC - m/z=74 Base peak

Hac өсі: сн, CH3 HC OCH, m/z=85 Thus the compound is HzC OCH methyl pentanoate

I have also confirmed with literature IR and mass spectrum of methyl pentanoate also called as Valeric acid methyl ester and it is a perfect match!