| Title: | Fractionation and DOSY NMR as Analytical Tools: From Model Polymers to a Technical Lignin |
| Author(s): | Montgomery JRD; Lancefield CS; Miles-Barrett DM; Ackermann K; Bode BE; Westwood NJ; Lebl T; |
| Address: | "School of Chemistry and Biomedical Sciences Research Complex, University of St Andrews and EaStChem, North Haugh, St Andrews, Fife KY16 9ST, U.K" |
| ISSN/ISBN: | 2470-1343 (Electronic) 2470-1343 (Linking) |
| Abstract: | "One key challenge hindering the valorization of lignin is its structural complexity. Artificial lignin-like materials provide a stepping stone between the simplicity of model compounds and the complexity of lignin. Here, we report an optimized synthesis of an all-G beta-O-4 polymer 1 designed to model softwood lignin. After acetylation, the polymer Ac-1(V) was fractionated using a protocol that involved only volatile organic solvents, which left no insoluble residue. Using diffusion ordered spectroscopy NMR in combination with gel permeation chromatography, it was revealed that this fractionated material behaved like a flexible linear polymer in solution (average alpha > 0.5). Acetylated kraft lignin was subsequently processed using the same fractionation protocol. By comparison with the model polymer, we propose that the acetylated kraft lignin is composed of two classes of materials that exhibit contrasting physical properties. One is comparable to the acetylated all-G beta-O-4 polymer Ac-1, and the second has a significantly different macromolecular structure" |
| Notes: | "PubMed-not-MEDLINEMontgomery, James R D Lancefield, Christopher S Miles-Barrett, Daniel M Ackermann, Katrin Bode, Bela E Westwood, Nicholas J Lebl, Tomas eng 2017/11/30 ACS Omega. 2017 Nov 30; 2(11):8466-8474. doi: 10.1021/acsomega.7b01287. eCollection 2017 Nov 30" |
