Pulping and biorefining
- General approach and principles
- Extraction-based methods
- Separation of valuable extractives from trees
- Choosing the right solvent – hydrophobic or hydrophilic?
- Stemwood extractives-based products
- Operation modes and procedures in industrial extraction processes
- Exudate gums and latexes
- Hot-water extraction
- Wood extractives – general description
- Factors contributing to the loss of extractives
- Chemical changes in extractives during storage
- Bark extractives – terpenes and terpenoids
- Bark extractives – polyphenols and other minor compounds
- Use of deep eutectic solvents
- Chemical and biochemical conversion
- Thermochemical conversion
- Kraft pulping
- Wood material handling systems
- Pulping process-general approach
- Pulping technologies
- Drying of chemical pulps
- Chemical (market) pulps drying plant applications
- Recovery of cooking chemicals and by-products
- Integrated biorefinery concepts
- Oxygen-alkali delignification
- Delignifying or lignin-removing bleaching
- Other delignification methods
- Chemimechanical pulping
- Mechanical pulping
- Pulp characterisation and properties
Reactions of extractives – oxygen-alkali delignification Extractives comprise an extraordinarily large number of diverse substances (i.e., several thousand individual compounds), mainly with low molecular masses.1 By a broad definition, these extractives are either soluble in neutral organic solvents or water. Thus, these substances may be both lipophilic and hydrophilic and are regarded as nonstructural wood
Authors & references
Author:
Raimo Alén, University of Jyväskylä
References:
- Alén, R. 2000. Structure and chemical composition of wood. In: Stenius, P. (Ed.). Forest Products Chemistry. Fapet, Helsinki, Finland. Pp. 11−57.
- Alén, R. 2000. Basic chemistry of wood delignification. In: Stenius, P. (Ed.). Forest Products Chemistry. Fapet, Helsinki, Finland. Pp. 58−104.
- Alén, R. 2011. Structure and chemical composition of biomass feedstocks. In: Alén, R. (Ed.). Biorefining of Forest Resources. Paper Engineersʼ Association, Helsinki, Finland. Pp. 17−54.
- Gellerstedt, G. 1996. Chemical structure of pulp components. In: Dence, C. W. and Reeve, D. W. (Eds.). Pulp Bleaching – Principles and Practice. Tappi Press, Atlanta, GA, USA. Pp. 91−111.
- Shin, S.-J., Schroeder, L. R. and Lai, Y.-Z. 2004. Impact of residual extractives on lignin determination in kraft pulps. Journal of Wood Chemistry and Technology 24(2):139−151.
- Shin, S.-J., Schroeder, L. R. and Lai, Y.-Z. 2006. Understanding factors contributing to low oxygen delignification of hardwood kraft pulps. Journal of Wood Chemistry and Technology 26(1):5−20.
- Salmela, M. 2007. Description of Oxygen-Alkali Delignification of Kraft Pulp Using Analysis of Dissolved Material. Doctoral Thesis. University of Jyväskylä, Finland.
- Shin, S.-J. and Kim, C.-H. 2006. Residual extractives in unbleached aspen and pine kraft pulps and their fate on oxygen delignification. Nordic Pulp and Paper Research Journal 21(2):260−263.
- Dence, C. W. 1996. Chemistry of chemical pulp bleaching. In: Dence, C. W. and Reeve, D. W. (Eds.). Pulp Bleaching − Principles and Practice. Tappi Press, Atlanta, GA, USA. Pp. 125−159.
- Holmbom, B. 2000. Resin reactions and deresination in bleaching. In: Back, E. L. and Allen, L. H. (Eds.). Pitch Control, Wood Resin and Deresination. Tappi Press, Atlanta, GA, USA. Pp. 231−244.
- Alén, R. and Sjöström, E. 1991. Formation of low-molecular-mass compounds during the oxygen delignification of pine kraft pulp. Holzforschung 45(Suppl.):83−86.
- Holmbom, B. 2011. Extraction and utilization of non-structural wood and bark components. In: Alén, R. (Ed.). Biorefining of Forest Resources. Paper Engineersʼ Association, Helsinki, Finland. Pp. 176−224.
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This page has been updated 19.05.2021