Activated lignins

Programs containing lignins as the primary polymeric dispersant are generally formulated to provide 30 to 50 ppm of active lignin product in the BW. 

Curing The wood is thermally treated at a temperature ranging from 150 °C to 190°C under dry conditions, for 12-16 hours. During this stage, reactions occur between the hemicellulose breakdown products and the activated lignin to form cross-links. The wood leaves this part of the process at less than 1 % moisture content. 

Johnson TM, Li JK (1991) Heterologous expression and characterization of an active lignin peroxidase from Phanerochaete chrysosporium using recombinant baculovirus. Arch Biochem Biophys 291 371-378... 

Figure 1. Proposed scheme to activate lignin for use in phenolic resins and as a feedstock for other polymeric products.

Agitation of P. chrysosporium cultures was originally found to strongly suppress ligninolytic activity -lignin —> and it was reported that LiP activity was... 

Furthermore, a procedure is known [79] in which activated lignin (hydrolyzed lignin treated at 200-230°C) is used as a contact Cl impregnated into a PE-based polymer blend with benzoic acid. The resultant hose is brought into contact with a dicyclohexilamine melt. Film extruded from this blend filled by the activated lignin becomes a VCl carrier as a result of interactions between benzoic acid and cyclohexilamine. 

Saha, D., Y. C. Li, Z. H. Bi et al. 2014. Studies on supercapacitor electrode material from activated lignin-derived mesoporous carbon. Langmuir 30 900-910. 

Some Important Phenylpropanoids Biological Activity Lignin... 

Chemical charge, Hquor composition, time of heatup, and time at temperature of reaction are all functions of the wood species or species mix being digested and the intended use of the pulp. A typical set of conditions for southern pine chips in the production of bleachable-grade pulp for fine papers is active alkaH, 18% sulfidity, 25% and Hquor-to-wood ratio, 4 1. Time of heatup is 90 min to 170°C time at temperature of reaction, 90 min at 170°C. Hardwoods require less vigorous conditions primarily because of the lower initial lignin content. 

Guaiacols. Cresote, obtained from the pyrolysis of beechwood, and its active principles guaiacol [90-05-1] (1) and cresol [93-51-6] (2) have long been used ia expectorant mixtures. The compounds are usually classed as direct-acting or stimulant expectorants, but their mechanisms of action have not been well studied. Cresol is obtained by the Clemmensen reduction of vanillin (3), whereas guaiacol can be prepared by a number of methods including the mercuric oxide oxidation of lignin (qv) (4), the ziac chloride reduction of acetovanillone (5), and the diazotization and hydrolysis of o-anisidine (6). 

Lu and Pizzi [83] showed that lignocellulosic substrates have a distinct influence on the hardening behavior of PF-resins, whereby the activation energy of the hardening process is much lower than for the resin alone [84]. The reason is a catalytic activation of the PF-condensation by carbohydrates like crystalline and amorphous cellulose and hemicellulose. Covalent bonding between the PF-resin and the wood, especially lignin, does not play any role [84]. 

An oxidative activation of the lignin also can be achieved in a biochemical way by adding enzymes (phenol oxidase laccase) to the spent sulfite liquor, whereby... 

MiTJANS M, GARCIA L, MARRERO E, viNARDELL M p (2001) Study of Ligmed-A, anantidiarrheal drug based on lignin, on rat small intestine enzyme activity and morphometry. J Vet Pharmacol Then 24 349-51. 

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