Question

ISL dll ULU FT-IR: What functional groups are present in your unknown? List IR frequencies and functional groups. 2 NMR: What information about your unknown can you get from the NMR? 3 MS: What is the possible molecular weight of the unknown? What other mass information is available for the mass spectrum? Index of Refraction: What is the refractive index of your liquid unknown? How does it compare to literature values of your liquid unknown? 5 What is the identity (name) of your unknown? Draw the structure.

Answer 1

1) IR: 3062: sp2 C-H stretching 1681: conjugated C O stretching 1598: aromatic C C stretching 1448: СНЗ rосking 1358: C-H bending 757: OOP C-H bending 688: ring bending As per the IR there is an aromatic ring in conjugation with ketone carbonyl. 2) NMR: The ratio is: 2.15: 1.27: thus the proton ratio is: 5H: 3H Thus the aromatic ring is monosubstituted benzene ring as all 5H are in the aromatic region and the methyl group with 3H is attached to electron withdrawing ketone carbonyl. 3) M+ 120 loss of 15 means presence of methyl ketone gives 105 and 77 corrospnds to benzene radi cal. 4) Litrature value of refractive index is n20/D 1.534 5) Name of unknown is: Acetophenone. "CНз 1-phenylethan-1-one