Last Chem Text

Question 1

Determine the functional groups in the compound

Answer 1

Phenol and ketone

Phenol is weakly acidic ph5 and doesn’t react with Na2Co3.
Orange ppt formed with 2,4-DNP shows carbonyl group present. Since no silver mirror with Tollens it’s not an aldehyde (must be a ketone)

Question 2

Carbon NMR. Using the spectrum and results from a and b determine the structure of the compound

Answer 2

There are 4 carbon environments between 110-160ppm.
There is a C-C between 20-30ppm and a C=O between 190-200ppm

DRAW STRUCTURE

Question 3

2-nitrophenol, 3-nitrophenol and 4-nitrophenol.

The student believes C NMR spectroscopy can be used to distinguish the three nitrophenols
Explain whether the student is correct

Answer 3

2-nitrophenol and 3-nitrophenol both have 6 carbon environments.
4-nitrophenol has 4 carbon environments.
We can distinguish 4-nitrophenol from the others but not between 2-nitrophenol and 3-nitrophenol

Question 4

NMR STEPS

Answer 4

Empirical formula, molecular formula

Proton environment, chemical shift, splitting pattern — TABLE

without D2O —

Other analysis

Overall structure of compound

Question 5

Use mass spectroscopy to deduce structure of Esters J L and M

Answer 5

J = CH3

L= CH2CH2CH3

M= CH(CH3)2

Question 6

The mass spectrum of Ester C is shown below.

Suggest possible structures for species responsible for peaks Y and Z in the mass spectrum

Answer 6

y (43) (CH3)2CH+

Z (71) (CH3)2CHCO+