| 1. |
- Abdelhamid, Hani Nasser, et al.
(författare)
-
Template-free and room temperature synthesis of hierarchical porous zeolitic imidazolate framework nanoparticles and their dye and CO2 sorption
- 2018
-
Ingår i: Green Chemistry. - : Royal Society of Chemistry (RSC). - 1463-9262 .- 1463-9270. ; 20:5, s. 1074-1084
-
Tidskriftsartikel (refereegranskat)abstract
- Hierarchical porous zeolitic imidazolate framework ZIF-8 nanoparticles have been synthesized using zinc nitrate, 2-methylimidazole (Hmim), and sodium hydroxide. Zinc hydroxide nitrate nanosheets were formed as intermediates that further transformed to hierarchical porous ZIF-8 after the addition of Hmim. These intermediates serve as in situ sacrificial templates and promote the formation of hierarchical porous ZIF-8 without the need for any other templates. The surface area and mesoporosity of the materials can be tuned by adjusting the concentration of NaOH. This method offers a fast and template-free approach for the synthesis of pure hierarchical porous ZIF-8 at room temperature with tunable porosity. The approach has been applied to synthesize two-dimensional ZIF leaf-like materials, ZIF-L. The synthesis of ZIF-8 and ZIF-L can be scaled up with high yields (>80%). The resulting ZIF-8 and ZIF-L materials show very good CO2 sorption properties. ZIF-8 nanoparticles show fast (<5 min), selective, and high efficiency (>95%) uptake of methyl blue in aqueous solution both without and in the presence of other dyes. The results open a new avenue for the understanding of the self-assembly and the formation of hierarchical porous ZIFs.
|
|
| 2. |
- Ahlford, Katrin, et al.
(författare)
-
Rhodium-catalyzed asymmetric transfer hydrogenation of alkyl and aryl ketones in aqueous media
- 2008
-
Ingår i: Green Chemistry. - : Royal Society of Chemistry (RSC). - 1463-9262 .- 1463-9270. ; 10:8, s. 832-835
-
Tidskriftsartikel (refereegranskat)abstract
- A novel lipophilic rhodium catalyst was evaluated in the enantioselective transfer hydrogenation of ketones in water using sodium formate as the hydride donor, and in the presence of sodium docecylsulfonate. Alkyl alkyl ketones were reduced in good yields and in moderate to good enantioselectivities, and the reduction of aryl alkyl ketones proceeded with excellent enantioselectivity (up to 97% ee).
|
|
| 3. |
- Ahlsten, Nanna, 1982-, et al.
(författare)
-
Rhodium-catalysed isomerisation of allylic alcohols in water at ambient temperature
- 2010
-
Ingår i: Green Chemistry. - : Royal Society of Chemistry (RSC). - 1463-9262 .- 1463-9270. ; 12:9, s. 1628-1633
-
Tidskriftsartikel (refereegranskat)abstract
- An environmentally benign method for the transformation of allylic alcohols into carbonyl compounds is described. Using [Rh(COD(CH3CN)(2)]BF4 (2) in combination with 1,3,5-triaza-7-phosphaadamantane (PTA, 1) as the catalytic system in water results in a very fast redox isomerisation of a variety of secondary allylic alcohols at ambient temperature. Also, some primary allylic alcohols can be isomerised into the corresponding aldehydes. The active complex, which in some cases can be used in catalyst loadings as low as 0.5 mol%, is formed in situ from commercially available reagents. Based on deuterium labelling studies, a tentative mechanism involving metal-enone intermediates is presented.
|
|
| 4. |
- Alexakis, Alexandros Efraim, et al.
(författare)
-
Modification of cellulose through physisorption of cationic bio-based nanolatexes - comparing emulsion polymerization and RAFT-mediated polymerization-induced self-assembly
- 2021
-
Ingår i: Green Chemistry. - : Royal Society of Chemistry (RSC). - 1463-9262 .- 1463-9270. ; 23:5, s. 2113-2122
-
Tidskriftsartikel (refereegranskat)abstract
- The polymerization of a bio-based terpene-derived monomer, sobrerol methacrylate (SobMA), was evaluated in the design of polymeric nanoparticles (nanolatexes). Their synthesis was accomplished by using emulsion polymerization, either by free-radical polymerization in the presence of a cationic surfactant or a cationic macroRAFT agent by employing RAFT-mediated polymerization-induced self-assembly (PISA). By tuning the length of the hydrophobic polymer, it was possible to control the nanoparticle size between 70 and 110 nm. The average size of the latexes in both wet and dry state were investigated by microscopy imaging and dynamic light scattering (DLS). Additionally, SobMA was successfully copolymerized with butyl methacrylate (BMA) targeting soft-core nanolatexes. The comparison of the kinetic profile of the cationically stabilized nanolatexes highlighted the differences of both processes. The SobMA-based nanolatexes yielded high T-g similar to 120 degrees C, while the copolymer sample exhibited a lower T-g similar to 50 degrees C, as assessed by Differential Scanning Calorimetry (DSC). Thereafter, the nanolatexes were adsorbed onto cellulose (filter paper), where they were annealed at elevated temperatures to result in polymeric coatings. Their morphologies were analysed by Field Emission Scanning Electron Microscopy (FE-SEM) and compared to a commercial sulfate polystyrene latex (PS latex). By microscopic investigation the film formation mechanism could be unravelled. Water contact angle (CA) measurements verified the transition from a hydrophilic to a hydrophobic surface after film formation had occured. The obtained results are promising for the toolbox of bio-based building blocks, focused on sobrerol-based monomers, to be used in emulsion polymerizations either for tailored PISA-latexes or facile conventional latex formation, in order to replace methyl methacrylate or other high T-g-monomers.
|
|
| 5. |
|
|
| 6. |
- Arshadi, Mehrdad, et al.
(författare)
-
Impact of supercritical extraction on solid fuel wood pellet properties and off-gassing during storage
- 2016
-
Ingår i: Green Chemistry. - : Royal Society of Chemistry (RSC). - 1463-9262 .- 1463-9270. ; 18, s. 2682-2690
-
Tidskriftsartikel (refereegranskat)abstract
- Biofuel pellets derived from wood raw material are an important carbon neutral source of energy. Their storage and bulk transportation can lead to serious hazards as a result of off-gassing (CO, CO2, CH4 combined with serious oxygen (O-2) depletion). Herein, supercritical carbon dioxide extraction (scCO(2)) has been demonstrated as an efficient tool in significantly reducing these emissions from wood pellets. 84% of the lipids and resin acids have been removed from the sawdust prior to pelletisation. Crucially, this work reports the first off-gassing measurements associated with lipid autoxidation in wood pellets post scCO(2) extraction of the sawdust. These off-gassing processes were considerably reduced for scCO(2)-extracted sawdust pellets, when compared to pellets prepared from virgin untreated sawdust (reference pellets). Significant reductions in the levels of CO, CO2 and CH4 (85, 85, and 94% respectively) were observed. A slight reduction in O-2 concentration (20% to 19.3%) was observed for the scCO(2)-pellets, while an 8% decrease (reduction in O-2 concentration from 20% to 12%) was observed for the reference. The results support a connection between the amount of lipids/resin acids and intermediate products of autoxidation (i.e. 71% reduction in aldehydes) and the off-gassing of CO, CO2 and CH4. Finally, there was low impact on the production, durability, calorific values and density of scCO(2) pellets compared to the reference pellets. This work demonstrated that scCO(2) extraction is effective as a pre-treatment technology for wood based pelletised fuels, considerably reducing the risks associated with off-gassing and oxygen depletion, while also highlighting potential chemicals and biofuels which could be generated from extracts.
|
|
| 7. |
- Arshadi, Mehrdad, et al.
(författare)
-
Pre-treatment and extraction techniques for recovery of added value compounds from wastes throughout the agri-food chain
- 2016
-
Ingår i: Green Chemistry. - 1463-9262 .- 1463-9270. ; 18, s. 6160-6204
-
Forskningsöversikt (refereegranskat)abstract
- The enormous quantity of food wastes discarded annually forces a look into alternatives for this interesting feedstock. Thus, food bio-waste valorisation is one of the current imperatives of society. This review is the most comprehensive overview of currently existing technologies and processes in this field. It tackles classical and innovative physical, physico-chemical and chemical methods of food waste pre-treatment and extraction for the recovery of added value compounds and detection by modern technologies and is an outcome of the COST Action EUBIS, TD1203 Food Waste Valorisation for Sustainable Chemicals, Materials and Fuels.
|
|
| 8. |
|
|
| 9. |
- Axelsson, Anton, 1991, et al.
(författare)
-
Organocatalytic valorisation of glycerol via a dual NHC-catalysed telescoped reaction
- 2017
-
Ingår i: Green Chemistry. - 1463-9262 .- 1463-9270. ; 19:11, s. 2477-2481
-
Tidskriftsartikel (refereegranskat)abstract
- A general telescoped reaction for the NHC-catalysed carbonation and aerobic esterification of glycerol and 2-amino-2-methylpropane-1,3-diol has been developed. The reaction provides highly functionalised glycerol derivatives in good to excellent yields (up to 95%) using low catalyst loadings and ambient conditions.
|
|
| 10. |
- Balakshin, Mikhail, et al.
(författare)
-
Spruce milled wood lignin : Linear, branched or cross-linked?
- 2020
-
Ingår i: Green Chemistry. - : Royal Society of Chemistry. - 1463-9262 .- 1463-9270. ; 22:13, s. 3985-4001
-
Tidskriftsartikel (refereegranskat)abstract
- The subject of lignin structure, critical for fundamental and practical reasons, is addressed in this study that includes a review of the methods applied to elucidate macromolecular branching. The recently available approaches for determination of the absolute molecular mass of spruce milled wood lignin (MWL) along with the quantification of terminal groups clearly indicate that MWL is significantly branched and cross-linked (with ∼36% lignin units partaking in these linkages). Results from independent methods imply that about half of the branching and crosslinking linkages involve aromatic rings, predominantly 5-5′ etherified units; meanwhile, a significant number of linkages are located in the side chains. Quantitative 13C NMR analyses suggest that the branches involve different aliphatic ether (alkyl-O-alkyl) types at the α- and γ-positions of the side chain, with intact β-O-4 linkages. While the exact structures of these moieties require further investigation, our results point to the fact that conventional lignification theory disagrees with the presence of such key moieties in softwood MWL and the observed high degree of branching/crosslinking. Potential reasons for the noted discrepancies are discussed.
|
|
