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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. [ABSTRACT FROM AUTHOR]

B Correction to: Cellulose b https://doi.org/10.1007/s10570-023-05063-5 In the original publication, the name of the co-author "Evelyn" was mistakenly processed as "S. Evelyn". The original article can be found online at https://doi.org/10.1007/s10570-023-05063-5. [Extracted from the article]

Considering the toxicity of the impurities of synthesized anthraquinone, this study clarified new catalytic compounds for kraft cooking with improved carbohydrate yield and delignification and less mutagenicity, which are important for ensuring the safety of paper products in contact with food. The 2-methylanthraquinone contents of teak (Tectona grandis) woods were 0.18–0.21%. Acetone extracts containing 2-methylanthraquinone from Myanmar and Indonesia teak woods as additives improved lignin removal during kraft cooking of eucalyptus wood, which resulted in kappa numbers that were 2.2–6.0 points lower than the absence of additive. Myanmar extracts and 2-methylanthraquinone improved carbohydrate yield in pulps with 1.7–2.2% yield gains. Indonesia extracts contained more deoxylapachol and its isomer than 2-methylanthraquinone. The residual content of 2-methylanthraquinone in the kraft pulp was trace. Although Ames tests showed that the Indonesia and Myanmar extracts were mutagenic to Salmonella typhimurium, 2-methylanthraquinone was not. The kraft pulp obtained with the additives should be safe for food-packaging applications, and the addition of 0.03% 2-methylanthraquinone to kraft cooking saves forest resources and fossil energy in industries requiring increased pulp yield. [ABSTRACT FROM AUTHOR]