Depolymerization of kraft lignin to phenolic compounds by electrochemical advanced oxidation in microreactor

Abstract

This research focuses on the depolymerization of kraft lignin to phenolic compounds that are valuable and useful in various industries. Depolymerization is performed using an electrochemical advanced oxidation process with the hydroxyl radicals. In this process, microreactors are used. It consists of a graphite anode and a stainless steel cathode. The results of the variables studied were current density (3.7 and 5.55 A/m2), residence time (100-400 s), base pH (9), the base difference (sodium hydroxide and potassium hydroxide). The experiment found that the major product is octadecamide and the minor product propyl guaiacol is increased when the current increases. On the other hand, some of the minor products increased when the decrease in current. However, residence time increases, both major and minor products decrease. In the base condition, The resulting octadecamide increased from increasing current and residence time. Give the major product is 1,3 dioxane and found the new minor products have been increased. In other words, increasing the current and residence time enhances the formation of hydroxyl radicals, resulting in a decrease of phenolic compounds. On the other hand, the base conditions can decrease the hydroxyl radicals, Especially potassium hydroxide. In addition, the study of dimer products for describing the pathway mechanism of phenolic compounds in microreactors.