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NMR chem lab 2 1.4-dinieIhoxybenzene 3-deuteropropanal CH_3COCH_2CH_2COCH_3. Sel

ID: 984013 • Letter: N

Question

NMR chem lab 2 1.4-dinieIhoxybenzene 3-deuteropropanal CH_3COCH_2CH_2COCH_3. Select the solvents that can be used in PMR spectroscopy which do not Interfere with the spectrum: carbon tetrachloride chloroform benzene-d_6 hexachloroacetone acetonitrile acetone methylene chloride DMF (dimethylformamide) D_2O. The PMR spectrum of dimethylformamlde (DMF) shows three singlets. Explain. When HBr is used as a catalyst in the pinacol rearrangement, more dimethylbutadiene is isolated than when H_2S0_4 is used. Why? In the calculation of the dimethylbutadiene/pinacolone product ratio, the integral peak heights were divided by 6 and by 9, respectively.

Explanation / Answer

5) carbon tetrechloride.

6) Nitrogen carries two electrons so it shows three signals

7) When H2SO4 is used then OH gr is protonated & expel out as a water forming pinacolon.

But if we use HBr then Elimination reaction takes place & water as well as bromine is expelled out forming dimethylbutadiene.