Use the following spectrum (compound B) to answer questions 34 iH NMR: (ppm) 4.1

Question

Use the following spectrum (compound B) to answer questions 34 iH NMR: (ppm) 4.1 ( H, t), 2.3 (2 H, q), 1.6 (2H, sextet), ?.1 (3H, t. 09 (3H, t) 34. The peak at around 4 ppm most likely corresponds to a. Ph-CHz-CH b. Ph-CHiCHa C. O-CH CH e. O-C-CH-CHz 35. The peak at around 2.3 ppm most likely corresponds to a. Ph-CH-CH b. Ph-CH-CH2 C. O-CHz-CH) d. O-CH-CH Use the following spectrum (compou nd F) to answer questions 36-37 'H NMR: 6 (ppm) 7.6 (bs, 1H), 7.4 (d, 2H), 6.8 (d, 2H), 4.0 (a, 2H), 2.1 (s, 3H), 14 (t, 3H) 36. Compound F contains a. A propyl group b. An ethyl group c. An isopropyl group d. An-CH2 group e. A CHs-O- group 37. The peak at around 7.6 ppm most likely corresponds to OeGO-? N- b. C, d. Ph-O-H 38. The peak at around 2.1 ppm most likely corresponds to a. Ph-CH b. Ph-OCH c. Ph-CH2-CH d. Ph-CH-OH e. Ph-CH-Cl 39. Compound F contains a. A monosubstituted benzene ring b. A 1,2-disubstituted benzene ring C. A 1,3-disubstituted benzene ring d. A 1,4-disubstituted benzene ring e. A 1,3,4-trisubstituted benzene ring

Explanation / Answer

Question 34 and 35)

1-H NMR analysis:

34) Given: chemical shift for (2H,t) =4.1 ppm

As it is having 2 protons and shows three split peaks (triplet) it must have 2 protons in its neighboring carbon -CH2-CH2 type

Also ph or benzyl group is not present as no chemical shift is observed around 7.0 (typical value for aromatic protons.

For protons present in alpha position to carbonyl functional group(O=C-CH-) , the chemical shift is observed between 2.0-3.0 ppm

but for R-O-CH- or protons alpha to ether group shows chemical shift between 4.0-4.5 ppm (the probable answer)

Answer: d)-O-CH2-CH2-

35) For protons present in alpha position to carbonyl functional group(O=C-CH-) , the chemical shift is observed between 2.0-3.0 ppm

So, answer :e) O=C-CH2-CH3

chemical shift(ppm) peak multiplicity (n+1) where n=# of protons in adjacent carbons with which the analysed proton spin-couples probable group 4.1 triplet for 2H (n=2) O-CH2-CH2 2.3 quartet for 2H (n=3) O=C-CH2-CH3 1.6 sextet for 2H(n=5) CH3-CH2-CH2- 1.1 triplet for 3H(n=2) CH3-CH2- 0.9 triplet for 3H (n=2) CH3-CH2-CH2-

Related Questions

Navigate

• Browse (All)
• Browse U
• Subjects

---