Deoxylapachol in Tectona grandis wood as a catalyst for delignification and carbohydrate protection during the kraft cooking of eucalyptus wood

Kraft cooking is the predominant technology in the pulp and paper industry. However, it is necessary to improve its efficiency and yield. The use of catalysts in kraft cooking increases pulp yield, reduces lignin content in pulp fibers, and energy consumption. In this study, natural 2-methylanthraquinone (2-MAQ) and deoxylapachol were isolated from the acetone extracts of Indonesian Jepara Tectona grandis (teak) wood using column chromatography and used as catalysts in alkaline cooking. Gas chromatography–mass spectrometry revealed that the extract contained deoxylapachol, iso-deoxylapachol, and 2-MAQ. The Indonesian Gunung Kidul teak wood extract also contained lapachol. The kraft cooking time profile of Eucalyptus globulus wood at 145 ºC and charged with 17% active alkali demonstrated the ability of deoxylapachol to enhance the delignification rate and retain carbohydrates. The lignin content in the kraft-deoxylapachol cooking pulp was determined to be lower than that of the control pulp prepared without catalyst. The molecular weights determined for dissolved lignin in black liquor revealed that the addition of deoxylapachol accelerated lignin decomposition; meanwhile, 86% of the carbohydrates were retained at the end of the kraft-deoxylapachol cooking process. An approximately 0.8–1.2% higher pulp yield was obtained when deoxylapachol was added compared to that obtained in the absence of the catalyst. This study showed that natural deoxylapachol from teak wood can be a promising cooking catalyst for the pulp and paper industry and potentially offers a beneficial impact on society and the environment.