| 1. |
- Di Francesco, Davide, et al.
(författare)
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Ductile Pd-Catalysed Hydrodearomatization of Phenol-Containing Bio-Oils Into Either Ketones or Alcohols using PMHS and H2O as Hydrogen Source
- 2018
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Ingår i: Advanced Synthesis and Catalysis. - : Wiley. - 1615-4150 .- 1615-4169. ; 360:20, s. 3924-3929
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Tidskriftsartikel (refereegranskat)abstract
- A series of phenolic bio-oil components were selectively hydrodearomatized by palladium on carbon into the corresponding ketones or alcohols in excellent yields using polymethylhydrosiloxane and water as reducing agent. The selectivity of the reaction was governed by the water concentration where selectivity to alcohol was favoured at higher water concentrations. As phenolic bio-oil examples cardanol and beech wood tar creosote were studied as substrate to the developed reaction conditions. Cardanol was hydrodearomatized into 3-pentadecylcyclohexanone in excellent yield. From beech wood tar creosote, a mixture of cyclohexanols was produced. No hydrodeoxygenation occurred, suggesting the applicability of the reported method for the production of ketone-alcohol oil from biomass.
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| 2. |
- François, Camille, et al.
(författare)
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Design and synthesis of biobased epoxy thermosets from biorenewable resources
- 2017
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Ingår i: Comptes rendus. Chimie. - : Elsevier BV. - 1631-0748 .- 1878-1543. ; 20:11-12, s. 1006-1016
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Tidskriftsartikel (refereegranskat)abstract
- Biobased diepoxy synthons derived from isoeugenol, eugenol or resorcinol (DGE-isoEu, DGE-Eu and DGER, respectively) have been used as epoxy monomers in replacement of the diglycidyl ether of bisphenol A (DGEBA). Their curing with six different biobased anhydride hardeners leads to fully biobased epoxy thermosets. These materials exhibit interesting thermal and mechanical properties comparable to those obtained with conventional petrosourced DGEBA-based epoxy resins cured in similar conditions. In particular, a high T-g in the range of 90-130 degrees C and instantaneous moduli higher than 4.3 GPa have been recorded. These good performances are very encouraging, making these new fully biobased epoxy thermosets compatible with the usual structural application of epoxy materials.
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| 3. |
- Olofsson, Johan, et al.
(författare)
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Effects of summer grazing by reindeer on composition of vegetation, productivity and nitrogen cycling
- 2001
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Ingår i: Ecography. - : Wiley. - 0906-7590 .- 1600-0587. ; 24:1, s. 13-24
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we investigated the effect of reindeer grazing on tundra heath vegetation in northern Norway. Fences. erected 30 yr ago, allowed us to compare winter grazed, lightly summer grazed and heavily summer grazed vegetation at four different sites. At two sites, graminoids dominated the heavily grazed zone completely, while ericoid dwarf shrubs had almost disappeared. In the other two areas, the increase of graminoids was almost significant. At one of the sites where graminoids dominated the heavily grazed area. we also measured plant biomass, primary production and nitrogen cycling. In this site: heavy grazing increased primary production and rate of nitrogen cycling, while moderate grazing decreased primary production. These results were inconsistent with the view that the highest productivity is found at intermediate grazing pressure. These results rather support the hypothesis that intensive grazing can promote a transition of moss-rich heath tundra into productive, graminoid-dominated steppe-like tundra vegetation. More over the results suggests that intermittent intensive reindeer grazing can enhance productivity of summer ranges.
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| 4. |
- Rautiainen, Sari, et al.
(författare)
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Lignin Valorization by Cobalt-Catalyzed Fractionation of Lignocellulose to Yield Monophenolic Compounds
- 2019
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Ingår i: ChemSusChem. - : Wiley. - 1864-5631 .- 1864-564X. ; 12:2, s. 404-408
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Tidskriftsartikel (refereegranskat)abstract
- Herein, a catalytic reductive fractionation of lignocellulose is presented using a heterogeneous cobalt catalyst and formic acid or formate as a hydrogen donor. The catalytic reductive fractionation of untreated birch wood yields monophenolic compounds in up to 34 wt % yield of total lignin, which corresponds to 76% of the theoretical maximum yield. Model compound studies revealed that the main role of the cobalt catalyst is to stabilize the reactive intermediates formed during the organosolv pulping by transfer hydrogenation and hydrogenolysis reactions. Additionally, the cobalt catalyst is responsible for depolymerization reactions of lignin fragments through transfer hydrogenolysis reactions, which target the beta-O-4' bond. The catalyst could be recycled three times with only negligible decrease in efficiency, showing the robustness of the system.
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