Question

An unknown compound X has the empirical formula C3H6O and a molecular ion peak in its mass spectrum at m/z 116. X shows no IR absorption at 3200-3600 cm^-1 but shows a peak at 1740 cm^-1. The H NMR spectral data of X is shown below. What is the most likely structure of X? 22. An unknown compound X has the molecular formula C6H14O. X shows a strong peak in its IR spectrum at 3000 cm^-1. The 1H NMR spectral data of N are given below. What is the most likely structure of X?

Absorption ζ H ratio
triplet 1.0 3
double 1.0 6
quartet 2.0 2
septet 3.5 1

Answer 1

Step-by-step explanation:

For an unknown compound whose empirical formula is C3H6O, the atomic no= 58, and since mass spectrum possesses a molecular ion at 116, then the twice amount of the empirical formula is called the molecular formula.

The degree of unsaturation pf C6H12O2 = 6 - (12/2) + 1

= 6 - 6 + 1

= 1 double bond or ring

Similarly, the IR shows a peak at 1740 cm⁻¹. This showcases the presence of a carbonyl group

Following the 1 HNMR data;

At 1.0 ppm, triplet 3H --> a methyl group is next to a CH2

At 1.2 ppm, doublet, 6H --> two methyl groups are next to a CH(isopropyl group)

At 2.0 ppm, quartet 2H --> CH2 next to the methyl group at 1.0 ppm

At 3.5 ppm, septet 1H --> CH group of the isopropyl group

The presence of the two oxygen also gives a hint that the structure seems to be an ester called isopropyl propionate.