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- Hribersek, Matic, 1992-, et al.
(författare)
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Solvent-free and ball mill-free catalytic C–H methylation
- 2023
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Ingår i: Green Chemistry. - : RSC Publishing. - 1463-9262 .- 1463-9270. ; 25:22, s. 9138-9145
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Tidskriftsartikel (refereegranskat)abstract
- An expedient, mechanochemical, operationally simple protocol is reported for the Rh-catalysed C–H methylation of (hetero)arenes under solvent-free conditions without the use of a ball mill. Reagent mixing and activation are delivered using simple pestle-and-mortar grinding and subsequent heating, providing access to the same sustainability benefits as ball milling without the need for specialised equipment. Calculated E-factors are identical to those of ball milling and 5–25 times lower than for solution based conditions. The C–H methylation displays complete regioselectivity and good functional group tolerance. Reaction mixture analyses using scanning electron microscopy and differential scanning calorimetry are described.
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| 2. |
- Orebom, Alexander, et al.
(författare)
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Thermal and Mechanical Properties of Esterified Lignin in Various Polymer Blends
- 2021
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Ingår i: Molecules. - : MDPI AG. - 1431-5157 .- 1420-3049. ; 26:11
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Tidskriftsartikel (refereegranskat)abstract
- Lignin is an abundant polymeric renewable material and thus a promising candidate for incorporation in various commercial thermoplastic polymers. One challenge is to increase the dispersibility of amphiphilic lignin in lipophilic thermoplastic polymers We altered Kraft lignin using widely available and renewable fatty acids, such as oleic acid, yielding more than 8 kg of lignin ester as a light brown powder. SEC showed a molecular weight of 5.8 kDa with a PDI = 3.80, while the Tg of the lignin ester was concluded to 70 °C. Furthermore, the lignin ester was incorporated (20%) into PLA, HDPE, and PP to establish the thermal and mechanical behavior of the blends. DSC and rheological measurements suggest that the lignin ester blends consist of a phase-separated system. The results demonstrate how esterification of lignin allows dispersion in all the evaluated thermoplastic polymers maintaining, to a large extent, the tensile properties of the original material. The impact strength of HDPE and PLA blends show substantial loss upon the addition of the lignin ester. Reconverting the acetic acid side stream into acetic anhydride and reusing the catalyst, the presented methodology can be scaled up to produce a lignin-based substitute to fossil materials.
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