Data on making uniform lignin building blocks via in-situ real-time monitoring of hydroxyethyl modification

Abstract

In this work, a lab-designed apparatus was developed to collect and record the CO2 amount during the hydroxyethyl modification of lignin. We presented the CO2 volume amount and the production rate under different reaction conditions (80 – 120 °C and 2 – 6 hrs). Nuclear magnetic resonance spectroscopy was performed to analyze the chemical structure of the hydroxyethyl lignin corresponding with different amounts of CO2 that evolved during the reaction. The aliphatic hydroxyl, aromatic hydroxyl, and carboxylic acid groups were analyzed and tabulated. The acetylated hydroxyethyl lignin samples were characterized by 13C NMR to obtain the aliphatic hydroxyl (primary and secondary), phenol (ortho substituted and ortho-free), hydroxyethyl, methoxy, and aromatic hydrogen groups semi-quantitatively. Fourier-transform infrared (FTIR) spectroscopy was adopted to analyze the surface functional groups including alkyl aryl ether bond, carboxylic acid groups, and aromatic hydroxyl groups. Gel permeation chromatography combined with a multi-angle light scattering detector and differential refractive index detector were used to obtain the molar mass of lignin before and after the modification.