Lignin dissolution under the impact of the "acetic acid-catalyst" reactionsystem

Dioxan lignin is treated with 96% acetic acid at 120 degrees, liquid:lignin ratio of 7:1 and catalyst concentration (HCl or AlCl3) in the acid -0.0375 mol/L. Changes in both dissolved and undissolved lignin are followed in ti me. Dissolved lignin is divided into two fractions depending on the degree of destruction. Some basic chemical characteristics of the higher molecular fraction of dissolved lignin are determined. It was found that lignin diss olution is most active in the presence of AlCl3, less active with HCl as a catalyst and slowest without a catalyst.