The preparation of diverse homologs from lead compounds has been a common and important practice in medicinal, mechano, polymeric, and many other branches of chemistry. The homologation of alkenes, though important, r...
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The preparation of diverse homologs from lead compounds has been a common and important practice in medicinal, mechano, polymeric, and many other branches of chemistry. The homologation of alkenes, though important, remains challenging due to the difficulty of (CH 2 ) n insertion into the main carbon chain of alkenes compared to chains containing other polar functional groups. Here, we report the homologation of both terminal and internal alkenes by using acetylene as a cheap and abundant C 2 feedstock. The process involves an in-situ transformation of alkenes into boranes and then into elongated alkenes, during which direct (CH 2 ) n insertion is avoided. The reaction can be carried out iteratively to achieve up to a 12-carbon elongation.
Integrating g-C3N4 nanotubes (CNTs) with nano-sized metal oxides to fabricate highly structured composites enables the innovative design of efficient Au-supported catalysts in environmental remediation applications. H...
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Correction for ‘Facile synthesis and isolation of 5-hydroxymethylfurfural from diphenyl sulfoxide’ by Tongtong Zhang et al., Green Chem., 2021, 23, 3241–3245, https://***/10.1039/D1GC00302J.
Correction for ‘Facile synthesis and isolation of 5-hydroxymethylfurfural from diphenyl sulfoxide’ by Tongtong Zhang et al., Green Chem., 2021, 23, 3241–3245, https://***/10.1039/D1GC00302J.
Vitrimers represent an emerging class of polymericmaterials that combine the desirable characteristics of both thermoplastics and thermosets achieved through the design of dynamic covalent bonds within the polymer ne...
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Vitrimers represent an emerging class of polymericmaterials that combine the desirable characteristics of both thermoplastics and thermosets achieved through the design of dynamic covalent bonds within the polymer networks. However, these materials are prone to creep due to the inherent instability of dynamic covalent bonds. Consequently, there are pressing demands for the development of robust and stable dynamic covalent chemistries. Here, we report a catalyst-free α-acetyl cinnamate/acetoacetate (α-AC/A) exchange reaction to develop vitrimers with remarkable creep resistance. Small-molecule model studies revealed that the α-AC/A exchange occurred at temperatures above 140 °C in bulk, whereas at 120 °C, this reaction was absent. For demonstration in the case of polymers, copolymers derived from common vinyl monomers were crosslinked with terephthalaldehyde to produce α-AC/A vitrimers with tunable thermal and mechanical performance. All resulting α-AC/A vitrimers exhibited high stability, especially in terms of creep resistance at 120 °C, while retaining commendable reprocessability when subjected to high temperatures. This work showcases the α-AC/A exchange reaction as a novel and robust dynamic covalent chemistry capable of imparting both reprocessability and high stability to cross-linked networks.
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