Question

1. (16 points) Shown below are IR and MS data for a compound with a molecular formula of C3H₂O

a) Identify the functional groups
responsible for the labeled
absorptions in the IR spectrum.
i) 1601 cm¹
ii) 1691 cm¹
Relative Intensity
100-
80-
m/z
rel. Intensity
22.6
73.1
105 100.0
120
26.2
$1.0
77.0
50 60
TRATT
100 110 120
1601 cm
1691 cm³
iii) From the parent,
what mass is lost to form
the base peak at m/z =
105?
iv) What is the likely
structure of that
fragment that is lost
to form m/z 105?
70
m/z
v) From the parent, what mass is lost to form the m/z = 77 peak?

Answer 1

i) 1601 cm¹ - This absorption is likely from a C=O stretching vibration indicative of an aldehyde or ketone functional group.

ii) 1691 cm¹ - This absorption is likely from an O-H stretching vibration indicative of an alcohol functional group.

iii) From the parent, the mass lost to form the base peak at m/z = 105 is 17 amu.

iv) The likely structure of the fragment that is lost to form m/z 105 is C2H2O.

v) From the parent, the mass lost to form the m/z = 77 peak is 28 amu.

vi) The likely structure of the fragment that is lost to form m/z 77 is C2H3O.

Step-by-step explanation: