. 2021 Jan 21;6(4):2999–3016. doi: 10.1021/acsomega.0c05387

Table 1. Peak Assignment from FT-IR Spectroscopy of Functional Groups of Bio-oil⁵⁶⁻⁵⁸.

peak	wavenumber (cm^–1)	functional group	class of compound
1	3350	O–H stretching	polymeric O–H
2	2960, 2925, 2850	CH, CH₂ stretching, C–H stretching	alkanes
3	2354.66	C–O stretching	phenol, alcohols, esters, ether
4	1690–1759, 1700	C=O stretching	ketones, aldehydes, carboxylic acids, mono-alkyl ester
	1602–1656	C=C stretching	alkenes
	1515	C=C ring stretching	aromatics
	1282, 1205	C–O–C stretching	phenol, ester, ethers
	1240, 1260	C–H stretching	aromatics
5	1195, 1110, 1043	C–O stretching	phenol, ester, ethers
	885	C–H deformation	aromatics
	750	adjacent C–H deformation	aromatics
	696	out-of-plane =CH deformation	alkenes
	615	out-of-plane O–H deformation	polymeric O–H

Table 1. Peak Assignment from FT-IR Spectroscopy of Functional Groups of Bio-oil56−58.