Wood extractives

Ongoing research projects

Effect of Fiberline on Chemical Transformation of Wood Extractives- Reaction Mechanism and Recovery (BE-Stilbene)
Buildup of the secondary-form wood extractives decreases the pulp mill’s productivity as they partly form different carry-over pitch (or scale) components at the fiberline, leading to excessive chemical consumption. The native-form wood extractives (prior to the fiberline) have been well researched for decades, but there is not enough scientific data to investigate the reaction mechanisms behind its secondary form (in the fiberline). Industrial-scale separation / recovery process, however, is largely dependent on the reaction mechanisms that occur throughout the fiberline. If we want to utilize them in future biorefineries, we need to know how they react in the fiberline and where they can be recovered (in the form having their maximum commercial value) before being chemically spoiled (or reacted). CIMANET project BE-Stilbene is designed to find ways to gain essential knowledge of the reactions (such as degradation, oxidation or formation of newly secondary products) between the wood extractives and cooking (kraft and sulfite)/ bleaching chemicals.

Related publication:
Dou, J.*; Sui, M.; Malinen, K.; Pesonen, T.; Isohanni, T.; Vuorinen, T. Spruce Bark Stilbenes as a Nature-inspired Sun Blocker for Sunscreens. (2022-03-02) Green Chem. 24, 2962−2974. https://doi.org/10.1039/D2GC00287F.

Understanding the Role of Wood Extractives in Formation of Pitch Deposits (WEPitch)
Control of wood extractives has a vital role in closing the water loops in pulp mills, thus helping the pulp and paper industry to achieve the “zero effluent” target. As there is no efficient way to control and remove them from the fiber line, extractives can be a technical challenge. Wood extractives cause a lot of effort to the process and can create serious problems, because they flow and accumulate in water, forming pitch deposits. The extractives retained in the pulps may adversely affect the physiochemical properties of the products. Efficient removal of pitch deposits from the fiber line is currently hampered by the lack of knowledge of their full chemical characteristics and the exact formation mechanism. The Industry- and FinnCERES- jointly funded project WEPitch (2024-2028) is designed to find ways to gain essential knowledge to understand, prevent and control deposit formation and improve the overall operation, revenue and quality performance of the pulp and paper mill.

Related publication:
Dou, J.*; Niemelä, Klaus*; Haatainen, Tiina; Tervola, Pekka; Vehmaa Janne*. Investigation of pitch deposits throughout the fibre line of softwood pulp mills. (2023-03-28) J. Cleaner Prod. 405, 136940. https://doi.org/10.1016/j.jclepro.2023.136940.

Stability enhancement of softwood (sawdust wood and bark) stilbene through chemical functionalization as ultra stable UV-filters in sunscreen (FACE+)

Trans-stilbenes can be isomerized to their cis-isomers under sunlight, and the cis-isomers are prone to undergo a Mallory reaction yielding polycyclic aromatic hydrocarbons. This preference is very hard to overcome as it is strictly under orbital symmetry control. The Academy of Finland Research Fellow project (2023–2027) will focus on functionalizing the recovered stilbene from pine wood sawdust and spruce bark as ultra-stable UV-filter alternatives for sunscreen. This may improve the stilbene stability 1000-fold without losing its UV-absorbing activity. These materials are today merely burned for energy, but when using them to added-value chemicals, it could allow more incomes for the Finnish forest owners and industry.

Related publications:

Dou, J.*; Multia, Evgen; Dong, Xinyue; Wang, Lei*; Vuorinen, Tapani. Valorization of long-neglected spruce bark and bark-press effluents through integrated utilization of stilbenoids and pectin. (2023) Chem. Eng. J. https://doi.org/10.1016/j.cej.2023.144122.