15. Analytical Techniques:IR, NMR, Mass Spect

Give the spectral assignments for the protons in isobutyl alcohol (Solved Problem 13-4). For example, H^a is a singlet, area = 1, at δ2.4.

Propose chemical structures consistent with the following NMR spectra and molecular formulas. In spectrum (a), explain why the peaks around δ1.65 and δ3.75 are not clean multiplets, but show complex splitting.

(a) <IMAGE>

Draw the NMR spectra you expect for the following compounds.

(b)

Draw the NMR spectra you expect for the following compounds.

(a)

Identify each of the following compounds from its molecular formula and its ¹H NMR spectrum:

b. C₆H₁₂O

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Identify each of the following compounds from the ¹H NMR data and molecular formula:

c. C₅H₁₀O₂: a 3H triplet at 1.15 ppm

a 3H triplet at 1.25 ppm

a 2H quartet at 2.33 ppm

a 2H quartet at 4.13 ppm

Describe the ¹H NMR spectrum you would expect for each of the following compounds, indicating the relative positions of the signals:

f.

Explain how the following compounds, each with the same molecular formula, could be distinguished by their ¹H NMR spectra.

Describe the ¹H NMR spectrum you would expect for each of the following compounds, indicating the relative positions of the signals:

k.

Describe the ¹H NMR spectrum you would expect for each of the following compounds, indicating the relative positions of the signals:

g. CH₃CH₂OCH₂CH₃

The following ¹H NMR spectra are for four compounds, each with molecular formula of C₆H₁₂O₂. Identify the compounds.

c. <IMAGE>

Sketch the following spectra that would be obtained for 2-chloroethanol:

b. The ¹H NMR spectrum for a sample of the alcohol that contains a trace amount of acid.

Sketch the following spectra that would be obtained for 2-chloroethanol:

a. The ¹H NMR spectrum for an anhydrous sample of the alcohol.

The ¹H NMR spectra of three isomers with molecular formula C₇H₁₄O are shown here. Which isomer produces which spectrum?

b. <IMAGE>

An alkyl halide reacts with an alkoxide ion to form a compound whose ¹H NMR spectrum is shown here. Identify the alkyl halide and the alkoxide ion. (Hint: See Section 9.15.)

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