Question

The proton NMR spectrum in Figure $19-41$is for a compound of empirical formula ${\mathrm{C}}_4{\mathrm{H}}_3\mathrm{O}$. Identify the compound.

Short answer

The compound is${\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{COCH}}_3$.

Step-by-step solution

Existence of Triplet

The spectrum indicates that the existence of three types of protons

Existence of triplet at$\delta =1.06$shows the existence of$-{\mathrm{CH}}_3$collection adjacent to$-{\mathrm{CH}}_2$group.

Existence of Singlet

Existence of singlet at $\delta =2.09$shows the existence of $-{\mathrm{CH}}_3$ collection in other proton free surroundings.

Existence of a quadrat

Existence of a quadrat at $\delta =2.49$shows the existence of $-{\mathrm{CH}}_2$collection adjacent to $-{\mathrm{CH}}_3$group.

Therefore the compound is${\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{COCH}}_3$.