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 (DES)
- 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 lignin – acid suphite pulping In sulphite pulping, two types of reactions, i) sulphonation and ii) hydrolysis, are responsible for delignification.1-3 Sulphonation generates hydrophilic sulphonic acid (-SO3H) groups, while hydrolysis breaks aryl ether linkages between the phenylpropane units, thus lowering the average molar mass and creating new free phenolic hydroxyl (aryl-OH) groups. Most
Authors & references
Author
Raimo Alén, University of Jyväskylä
References
- 1. Sjöström, E. 1993. Wood Chemistry – Fundamentals and Applications. 2nd edition. Academic Press, San Diego, CA, USA. Pp. 119–140.
- 2. Alén, R. 2000. Basic chemistry of wood delignification. In: Stenius, P. (Ed.). Forest Products Chemistry. Fapet, Helsinki, Finland. Pp. 58−104.
- 3. Alén, R. 2011. Principles of biorefining. In: Alén, R. (Ed.). Biorefining of Forest Resources. Paper Engineers’ Association, Helsinki, Finland. Pp. 55−114.
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Exercises
This page has been updated 22.12.2020