Optimization of the Process of Abies Wood Peroxide Delignification in the Medium “Formic Acid-Water” in the Presence of TiO₂ Catalyst

Abstract

The experimental and mathematical optimization of abies wood peroxide delignification process in the formic acid – water medium in the presence of TiO₂ catalyst was carried out. It was established that in the temperature range 70-100 °С the rate constants of the delignification process vary between 0.4 and 3.2 · 10-4 min-1. The optimal parameters for the production of cellulose product with a residual lignin content of ≤ 3 wt.% were determined (temperature 100 °С, concentration Н₂О₂ 10 wt.%, НCOOН 38 wt.%, LWR 15, time 4 h). The features of abies wood peroxide delignification processes in the presence of TiO₂ catalyst in “ formic acid – water” and “acetic acid – water” were compared. It was shown the possibility of abies wood fractionation in the medium “ formic acid-water” to high-quality cellulose with the yield of 94 wt.% (the content of residual lignin 2.3 wt.%) and to low molecular weight lignin with the yield of 21 wt.% (average molecular weight 1854 g/mol and polydispersity 1.65). The obtained chemically active lignin can be used for the production such valuable products as enterosorbents, nanoporous carbon materials, aerogels