Polymerization of coniferyl alcohol

Foumand, D. Cathala, B. Lapierre, C. Initial steps of the peroxidase-catalyzed polymerization of coniferyl alcohol and/or sinapyl aldehyde capillary zone electrophoresis study of pH effect. Phytochemistry 2003, 62, 139-146. 

Figure 1. Formation of guaiacyl lignin and lignin-carbohydrate complexes (LCC) via dehydrogenative polymerization of coniferyl alcohol.

Already in 1897 Klason [52] suggested that gymnosperm lignin is derived from coniferyl alcohol. On the basis of experiments using isoeugenol as a model substance, Erdtman [53] advanced the hypothesis that lignin is a product of the oxidative polymerization of coniferyl alcohol ... 

Guan, S. Y., Mylnar, J., and Sarkanen, S., 1997, Dehydrogenative polymerization of coniferyl alcohol on macromolecular lignin templates,... 

Oxidative coupling polymerization provides great utility for the synthesis of high-performance polymers. Oxidative polymerization is also observed in vivo as important biosynthetic processes that, when catalyzed by metalloenzymes, proceed smoothly under an air atmosphere at room temperature. For example, lignin, which composes 30% of wood tissue, is produced by the oxidative polymerization of coniferyl alcohol catalyzed by laccase, an enzyme containing a copper complex as a reactive center. Tyrosine is an a-amino acid and is oxidatively polymerized by tyrosinase (Cu enzyme) to melanin, the black pigment in animals. These reactions proceed efficiently at room temperature in the presence of 02 by means of catalysis by metalloenzymes. Oxidative polymerization is observed in vivo as an important biosynthetic process that proceeds efficiently by oxidases. 

The network structure of lignin, which is made of phenol units, coagulates the cell wall in wood tissue, which is composed of cellulose and hemicellulose. Lignin is currently a waste product because of its complicated structure [1-4], It is produced by an oxidative polymerization of coniferyl alcohol, sinapil alcohol, and cumarol alcohol (Figure 1) catalyzed by metalloenzymes such as laccase and peroxidases. Laccase is a protein whose active center contains four coppers per one subunit [5-20],... 

Adler and Freudenberg reported a detailed study [21] of the polymerization of coniferyl alcohol with metalloenzymes. Coniferyl alcohol is activated by metal ions to form a radical that can be represented by four resonance states (Eq. 4) and dimerizes by coupling. In the early stage of the reaction, the formation of... 

This product may be derived from a glyceraldehyde-2-aryl ether unit formed via a displacement reaction in the dehydrogenative polymerization of coniferyl alcohol (Lundquist et al 1967)... 

K Radotic, J Zakrzewska, D Sladic, and M Jeremic. Study of Photochemical Reactions of Coniferyl Alcohol. I. Mechanism and Intermediate Products of UV Radiation-Induced Polymerization of Coniferyl Alcohol. Photochem. Photobiol. 65 284—291, 1997. 

R Kondo, T Sako, T limori, H Imamura. Formation of glycosidic lignin-carbohydrate complex in the enzymatic dehydrogenative polymerization of coniferyl alcohol. Mokuzai Gakkaishi 36 332-338, 1990. 

Polymerization of Coniferyl Alcohol (Monomer of Lignins) at the Air/Water Interface... 

Polymerization of coniferyl alcohol is attempted at the air/water interface. The polymerization process was monitored by surface tension, ellipsometry and neutron reflectivity. The formation of the interfacial layer was found to proceed according to two steps formation of a dilute layer and then densification. 

Figure 1 Surface tension and ellipticity pB during the polymerization of coniferyl alcohol at the air/water interface...

Figure 3 Variation of thickness (/l), DHP volume fraction () and surface concentration during the polymerization of coniferyl alcohol determined by neutron reflectivity...

Polymerization of coniferyl alcohol begins with a dehydrogenation through the action of the enzyme laccase. This produces the radical of... 

In vitro synthesis of lignin, a typical phenolic biopolymer, was claimed by the HRP-catalyzed terpolymerization of lignin monomers, p-coumaryl alcohol, coniferyl alcohol, and sinapyl alcohol (14 80 6 mol%) in an extremely dilute aqueous solution at pH 5.5 (282). Dialysis membrane method was applied to the polymerization of coniferyl and sinapyl alcohols, yielding insoluble polymeric materials (283). In the HRP-polymerization of coniferyl alcohol in the presence of a small amount of lignin component, the molecular weight distribution became much broader than that in the absence of lignin (284). 

Lignin is formed by the dehydrogenative polymerization of coniferyl, sinapyl, and p-coumaryl alcohol, which is catalyzed by a peroxidase and requires H2O2. A section of the structure of lignin formed by the polymerization of coniferyl alcohol is shown in Fig. 18.5. Lignins strengthen the walls of plant cells. They play a role as fiber in foods (cf. 15.2.4.2). 

Glasser WG, Glasser HR (1974) Simulation of reactions with lignin by computer (SIMREL). I Polymerization of coniferyl alcohol monomers. Macromolecules 7 17-27... 

---