Distinguishing between two possible structures: Let say you figured out that you have a pentanone molecule but you don’t know on which carbon the carbonyl group is located. You can use the fragmentation patter from a mass spec to figure it out. Let’s say that the spectra gave peaks at 29, 57, and 86If the carbonyl was on the 2nd carbon: CH3-CO-CH2CH2CH3Common fragments would be: 1. CH3CO = Mr-432. CH3CH2CH2CO = Mr-71If the carbonyl was on the 3rd carbon: CH3CH2-CO-CH2CH3The most common fragment would be: 1. CH3CH2CHO = Mr-57Since the peak at 57 matches the peak expected for pentan-3-one, this carbonyl must be on the third carbon.
đang được dịch, vui lòng đợi..