TABLE 6.
Approximate wavenumber assignments of major bands in ATR-FTIR results
| Region | Wavenumber range (cm−1) | Major bands (cm−1) | Functional groups | Comment |
|---|---|---|---|---|
| a | 3,170–3,630 | 3,380 or 3,445 | ν(O-H)/ν(N-H) | Very broad; change of center after HCl treatment |
| b | 2,800–3,020 | 2,920, 2,852 | ν(CH3)/ν(CH2) | Alkane |
| c | 1,570–1,770 | 1,610, 1,720 | νC = C/νC = O | Alkene/ester |
| d | 1,380–1,520 | 1,380, 1,465, 1,512 | δ(CH3)/δ(CH2)/δ(C = C) | CH3 and CH2 scissoring; aromatic C=C ring breathing |
| e | 1,230–1,290 | 1,240 | ν(C-O-C) | Ether |
| f | 980–1,200 | 1,029, 1,157 | ν(C-O)/δ(O-H) | 1,157 cm−1 eliminated by HCl treatment |
| g | 880–930 | 900 | ωo(C-H) | CH wag (out of plane) |
| h | 770–870 | 827 | δ(C-H)/τ(C-O-C) | Trisubstituted alkene/epoxide |
| i | 670–750 | 720 | ρ(CH2)n | Long-chain (CH2) rocking; n > 3 |