15. Analytical Techniques:IR, NMR, Mass Spect

Using curved arrows, show the principal fragments you would expect to see in the mass spectrum of each of the following compounds:

f.

Primary alcohols have a strong peak at m/z = 31.

a. What fragment is responsible for this peak?

What distinguishes the mass spectrum of 2,2-dimethylpropane from the mass spectra of pentane and isopentane?

Using curved arrows, show the principal fragments you would expect to see in the mass spectrum of each of the following compounds:

c.

The mass spectra of 1-methoxybutane, 2-methoxybutane, and 2-methoxy-2-methylpropane are shown below. Match each compound with its spectrum.

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The reaction of (Z)-2-pentene with water and a trace of H₂SO₄ forms two products. Identify the products from their mass spectra.

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A mass spectrum shows significant peaks at m/z = 87, 115, 140, and 143. Which of the following compounds is responsible for that mass spectrum?

The mass spectrum for a compound with molecular weight of 102 is shown below. Its IR spectrum has a broad, strong absorption at 3600 cm^–1 and a medium absorption at 1360 cm^–1.

b. Show the mechanism for formation of the peak at m/z = 84.

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Propose a fragmentation to account for each numbered peak in the mass spectrum of n-butyl isopropyl ether.

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In the mass spectrum of hexan-3-ol, identify the fragments arising from two α-cleavage fragmentations and one dehydration fragmentation.

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Suggest three ways that the following tertiary amine can fragment by α-cleavage. At which m/z would you expect to see peaks corresponding to these fragments?

For each of the molecules shown, predict the structure of at least one major fragment in the mass spectrum.

(d)

For each of the molecules shown, predict the structure of at least one major fragment in the mass spectrum.

(e)

Identify the peaks in the mass spectrum of octan-4-one that correspond to (a) α-cleavage.

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For each of the molecules shown, predict the structure of at least one major fragment in the mass spectrum.

(b)