Question

Fund the structure and the values for IR and NMR.

Also make a table with the integration numbers. Identify if it it is a singlet, doublet.. etc

IR/NMR Unknown Spectra #AA m.m. =(166.2 SC = 65.00.6EX 14:24129.00 SH = 6.02 0062x136.25 1:10:30 80 = 3.01 - VIV ! H MICRONG wavi " WAT WELCHONS

Answer 1

Step a)

From molecular weight 166.2

% of C = 65 = wt. of carbon = 0.65 x 166.2 = 108.03

atomic weight of carbon = 12

No of carbon = 108.03 /12 = 9

No of hydrogen = 0.0602 x 166.2 = 10.0005 = 10

166.2-108.03-10 = 48

48 may come fro 3 oxygen atoms

So molecular formula may be C₉H₁₀O₃

Step b)

IR spectrum give idea about ester functional group around 1700 cm^-1

Around 3000 cm^-1 sharp may be methoxy (alkoxy) group

So -COOR and OCH₃

Step c)

From NMR

4 different sets of proton groups

2:2:3:3 from intensity

7.99 ppm and 6.88 ppm from aromatic protons

3.82 and 3.87 ppm (upfield) are for aliphatic protons (high value indicates that the CH₃ groups are attached with hetero atom.

Based on these information the molecule is 4-Methoxy-benzoic acid methyl ester