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  • 1.
    Abdelhamid, Hani Nasser
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Assuit University, Egypt .
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Template-free and room temperature synthesis of hierarchical porous zeolitic imidazolate framework nanoparticles and their dye and CO2 sorption2018In: Green Chemistry, ISSN 1463-9262, E-ISSN 1463-9270, Vol. 20, no 5, p. 1074-1084Article in journal (Refereed)
    Abstract [en]

    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.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Lind, Jesper
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Mäler, Lena
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Adolfsson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Rhodium-catalyzed asymmetric transfer hydrogenation of alkyl and aryl ketones in aqueous media2008In: Green Chemistry, ISSN 1463-9262, E-ISSN 1463-9270, Vol. 10, no 8, p. 832-835Article in journal (Refereed)
    Abstract [en]

    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
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Lundberg, Helena
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Martin-Matute, Belen
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Rhodium-catalysed isomerisation of allylic alcohols in water at ambient temperature2010In: Green Chemistry, ISSN 1463-9262, E-ISSN 1463-9270, Vol. 12, no 9, p. 1628-1633Article in journal (Refereed)
    Abstract [en]

    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. Keskiväli, Juha
    et al.
    Rautiainen, Sari
    University of Helsinki, Finland.
    Heikkilä, Mikko
    Myllymäki, Teemu T. T.
    Karjalainen, Jaakko-Pekka
    Lagerblom, Kalle
    Kemell, Marianna
    Vehkamäki, Marko
    Meinander, Kristoffer
    Repo, Timo
    Isosorbide synthesis from cellulose with an efficient and recyclable ruthenium catalyst2017In: Green Chemistry, ISSN 1463-9262, E-ISSN 1463-9270, Vol. 19, no 19, p. 4563-4570Article in journal (Refereed)
    Abstract [en]

    Herein, we describe an efficient two-step pathway for isosorbide synthesis from cellulose with the use of new recyclable Ru-catalysts. We show that the oxidative and sulfonation treatments of the new Ru-catalysts increase the acidity and the hydrophilicity of the activated carbon support material, thus reducing the catalyst fouling caused by the build-up of insoluble products. Accordingly, the new Ru-catalysts are more resilient towards lignin containing cellulose than a commercial Ru/C catalyst, and the best Ru-catalyst maintains its high catalytic activity in four consecutive runs with dissolving pulp, microcrystalline cellulose and even with residual lignin containing bagasse pulp. Overall, our two-step approach provides isosorbide in high yields of 56-57 mol% ( 49-50 wt% of the substrate) from the cellulosic substrates.

  • 5.
    Kumaniaev, Ivan
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Subbotina, Elena
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Sävmarker, Jonas
    Larhed, Mats
    Galkin, Maxim V.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Samec, Joseph S. M.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Lignin depolymerization to monophenolic compounds in a flow-through system2017In: Green Chemistry, ISSN 1463-9262, E-ISSN 1463-9270, Vol. 19, no 24, p. 5767-5771Article in journal (Refereed)
    Abstract [en]

    A reductive lignocellulose fractionation in a flow-through system in which pulping and transfer hydrogenolysis steps were separated in time and space has been developed. Without the hydrogenolysis step or addition of trapping agents to the pulping, it is possible to obtain partially depolymerized lignin (21 wt% monophenolic compounds) that is prone to further processing. By applying a transfer hydrogenolysis step 37 wt% yield of lignin derived monophenolic compounds was obtained. Pulp generated in the process was enzymatically hydrolyzed to glucose in 87 wt% yield without prior purification.

  • 6.
    Nagendiran, Anuja
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Sörensen, Henrik
    Johansson, Magnus J.
    Tai, Cheuk-Wai
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Bäckvall, Jan-E.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Nanopalladium-catalyzed conjugate reduction of Michael acceptors - application in flow2016In: Green Chemistry, ISSN 1463-9262, E-ISSN 1463-9270, Vol. 18, no 9, p. 2632-2637Article in journal (Refereed)
    Abstract [en]

    A continuous-flow approach towards the selective nanopalladium-catalyzed hydrogenation of the olefinic bond in various Michael acceptors, which could lead to a greener and more sustainable process, has been developed. The nanopalladium is supported on aminofunctionalized mesocellular foam. Both aromatic and aliphatic substrates, covering a variation of functional groups such as acids, aldehydes, esters, ketones, and nitriles were selectively hydrogenated in high to excellent yields using two different flow-devices (H-Cube (R) and Vapourtec). The catalyst was able to hydrogenate cinnamaldehyde continuously for 24 h (in total hydrogenating 19 g cinnanmaldehyde using 70 mg of catalyst in the H-cube (R)) without showing any significant decrease in activity or selectivity. Furthermore, the metal leaching of the catalyst was found to be very low (ppb amounts) in the two flow devices.

  • 7.
    Olsén, Peter
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Morvan, Jennifer
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Sawadjoon, Supaporn
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Shatskiy, Andrey
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Johnston, Eric V.
    Åkermark, Björn
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Cyclic allylic carbonates as a renewable platform for protecting chemistry in water2018In: Green Chemistry, ISSN 1463-9262, E-ISSN 1463-9270, Vol. 20, no 14, p. 3186-3190Article in journal (Refereed)
    Abstract [en]

    The present work explores different cyclic allylic carbonates as a potential class of allylcarbamate precursors. The 5-membered carbonate formed a carbamate with very good thermal and pH stability, which could be cleanly deprotected in aqueous solution, in just 30 min with 2 mol% Pd(OAc)(2) as catalyst. The polar nature of the installed motif made it possible to deprotect highly unpolar substrates in water as solvent.

  • 8.
    Olsén, Peter
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Oschmann, Michael
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Johnston, Eric V.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Åkermark, Björn
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Synthesis of highly functional carbamates through ring-opening of cyclic carbonates with unprotected alpha-amino acids in water2018In: Green Chemistry, ISSN 1463-9262, E-ISSN 1463-9270, Vol. 20, no 2, p. 469-475Article in journal (Refereed)
    Abstract [en]

    The present work shows that it is possible to ring-open cyclic carbonates with unprotected amino acids in water. Fine tuning of the reaction parameters made it possible to suppress the degree of hydrolysis in relation to aminolysis. This enabled the synthesis of functionally dense carbamates containing alkenes, carboxylic acids, alcohols and thiols after short reaction times at room temperature. When Glycine was used as the nucleophile in the ring-opening with four different five membered cyclic carbonates, containing a plethora of functional groups, the corresponding carbamates could be obtained in excellent yields (> 90%) without the need for any further purification. Furthermore, the orthogonality of the transformation was explored through ring-opening of divinylenecarbonate with unprotected amino acids equipped with nucleophilic side chains, such as serine and cysteine. In these cases the reaction selectively produced the desired carbamate, in 70 and 50% yield respectively. The synthetic design provides an inexpensive and scalable protocol towards highly functionalized building blocks that are envisioned to find applications in both the small and macromolecular arena.

  • 9. Wang, Damao
    et al.
    Li, Jing
    Salazar-Alvarez, Germán
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). KTH Royal Institute of Technology, Sweden.
    McKee, Lauren S.
    Srivastava, Vaibhav
    Sellberg, Jonas A.
    Bulone, Vincent
    Hsieh, Yves S. Y.
    Production of functionalised chitins assisted by fungal lytic polysaccharide monooxygenase2018In: Green Chemistry, ISSN 1463-9262, E-ISSN 1463-9270, Vol. 20, no 9, p. 2091-2100Article in journal (Refereed)
    Abstract [en]

    The gene CCT67099 from Fusarium fujikuroi was shown to encode a novel enzyme from the Lytic Polysaccharide Monooxygenase (LPMO) Family AA11. The gene was expressed and a truncated version of the enzyme, designated as FfAA11, was purified from the periplasmic space of Escherichia coli cells at high yield. FfAA11 exhibited oxidative activity against - and -chitins, as well as lobster shells. Under optimised conditions, FfAA11 introduced 35 nmol of carboxylate (COO-) moieties per milligram of -chitin. These carboxylate groups were introduced onto the chitin surface under mild enzymatic oxidation conditions in an aqueous solution without changes to the crystallinity of the chitin fibres. FfAA11 was also combined with a simple and environmentally friendly chemical method that transforms recalcitrant chitins into desirable functionalised (nano)materials. The use of ethyl(hydroxyimino)cyanoacetate (Oxyma)-assisted click chemistry allowed the rapid modification of the surface of FfAA11-oxidized chitins, with a fluorescent probe, a peptide, and gold nanoparticles. The chemical steps performed, including the FfAA11 oxidase treatment and surface chemical modification, were achieved without the production of any toxic by-products or waste organic solvents. This approach represents a novel method for the greener production of chitin-based biomaterials.

1 - 9 of 9
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