Question

Q1- Below are pictures of the infrared spectra of 4-methyl-2-pentanol and 4-Methyl-1-pentene. Which spectrum belongs to which compound? Analyses the characteristic peaks? 4-methyl-2-pentanol СН3 ОН 4-Methyl-1-pentene CH3 H2C CH3 H3CCH3 5000 4000 WAVENUMBER IN CM! 3000 2500 2000 1500 1400 1300 1200 1100 1000 100 100 700 W TTTTTTTTTT PERCENT TRANSMITTANCE SELL 8. SRSX9XX 2 88::888882 • 45 11 12 13 14 15 - 9 10 WAVELENGTH IN MICRONS Compound name

Answer 1

The first spectra belongs to 4-methyl-2-pentanol

IR peaks: (OH, sharp) : 3650-3600cm^-1

(CH, stretch) : around 3000cm^-1(for sp^3)

(CH2, bend) : 1465cm^-1 (approx)

(CH3, bend) : 1375cm^-1 (approx)

(C-O-H,bend) : 1440-1220cm^-1 (s)

(C-O, stretch) : 1260-1000cm^-1

(CH2, bend(rocking)) : 720cm^-1 (long chain band)

The second spectra belongs to 4-methyl-1-pentene

IR peaks:

(C-H stretch) : around 3000cm^-1 (for sp^3)

(=C-H, stretch) : greater than 3000 cm^-1 ( 3095-3010cm^-1)

(=C-H, stretch) : out-of-plane (oop) bending occurs 1000-650cm^-1

(C=C , stretch) : 1660-1600 cm^-1

(CH2, bend) : 1465cm^-1 (approx)

(CH3, bend) : 1375 cm^-1 (approx)

(CH2, rocking) : about 720 cm^-1