Polymerization of lignin model compounds

Polymerization of Lignin Model Compounds. The controlled polymerization of several lignin model compounds at the meta positions was subsequently attempted (13) ... 

Rittstieg, K. Suumakki, A. Suortti, T. Kruus, K. Guebitz, G. Buchert, J. Investigations on the laccase-catalyzed polymerization of lignin model compounds using size-exclusion HPLC. Enzyme Microh. Technol. 2002, 31 (4), 403 10. 

At this point, it must be emphasized that, based on previous structural analysis of isolated lignins (27), appropriate lignin model compounds and synthetic dehydrogenatively polymerized (DHP) lignin preparations (28-... 

Model studies showed that veratryl alcohol could mediate the oxidation of a polymeric lignin model compound under certain conditions but could not mediate the oxidation of small molecule model compounds. 

Reactivity ratios between acrylated lignin model compound (Fig. 2), defined as Mi, with either MM A or S, defined as M2, were determined experimentally in accordance with standard procedures (15). These involve mixing two different vinyl monomers in various molar ratios with catalyst (i.e., benzoyl peroxide) and solvent, heating the mixture to achieve polymerization, and recovering the polymer by the addition of non-solvent, and centrifugation. The respective molar monomer fractions of the copolymer were determined by UV-spectroscopy in the cases where MMA served as M2, and by methoxyl content analysis in those cases in which S was the M2-species. The results were subjected to numerical treatments according to the established relationships of Kelen-Tiidos (17) and Yezrielev-Brokhina-Roskin (YBR) (18), and this is described elsewhere (15). 

Bifunctional acid chlorides were useful in crosslinking sulfonated lignin model compounds in aqueous alkali (Figure 4), but they behaved poorly during inter-molecular crosslinking of polymeric lignins (26). 

S Kawai, M Asukai, N Ohya, K Okita, T Ito, H Ohashi. Degradation of a non-phe-nolic beta-O-4 substructure and of polymeric lignin model compounds by laccase of Coriolus versicolor in the presence of 1-hydroxybenzotriazole. FEMS Microbiol. Lett. 170(l) 51-57, 1999. 

The hrst hve chapters (Part 1) present an overview of some methods that have been used in the recent hterature to calculate rate constants and the associated case studies. The main topics covered in this part include thermochemistry and kinetics, computational chemistry and kinetics, quantum instanton, kinetic calculations in liquid solutions, and new applications of density functional theory in kinetic calculations. The remaining hve chapters (Part II) are focused on apphcations even though methodologies are discussed. The topics in the second part include the kinetics of molecules relevant to combustion processes, intermolecular electron transfer reactivity of organic compounds, lignin model compounds, and coal model compounds in addition to free radical polymerization. 

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