Chemical decomposition, lignin

Thermal or chemical decomposition of lignin to produce oxyaromatics will grow when the depletion of low-cost petroleum becomes pronounced between 2015 and 2020 a.d. Examples of this technology would be nonionic surfac-... 

Chemical decomposition of hemicellulose and lignin, causing embrittlement and decreasing reinforce capacity of natural fibers because break the link between elementary fibers [31,40,41]. Chemical decomposition of these compounds, is caused because they are solubilized in the calcium hydroxide and in other alkalis produced during hydration reaction. 

Due to its importance in many fields of engineering and industry, wood is investigated by a broad spectrum of different methods, including all kinds of chemical analysis and chemical decomposition into its main components hemicellu-lose, cellulose and lignin, many physical procedures and some microbiological tests. They will be cited - if necessary - in connection with the presentation of thermoanalytical results. 

Waksman, S. A., and Iyer, K. R. N. (1933). Contribution to our knowledge of the chemical nature and origin of humus IV. Fixation of proteins by lignins and formation of complexes resistant to microbial decomposition. Soil Sci. 36, 69-82. 

The decomposition of lignin into aromatic repeat units is a long practiced art that reached its zenith around 1800 a.d. Production of chemicals by wood pyrolysis was extensively practiced until, between 1750 and 1850 a.d., coal slowly displaced wood as the major chemical source available to man. Wood is usually pyrolyzed at 260-4 lO C and lignin at 300-440 C to produce 50 wt % charcoal, 10-15% tar, and lesser amounts of 2-propanone, ethanoic acid, and methanol [16-181. The tar is often called wood creosote and is a complex mixture of substituted phenols and aromatics. It contains phenol, 2- and 4-methylphenol, 2,4-dimethylphenol, 2-methoxyphenol, 4-methyl-2-methoxyphenol, and 4-ethyl-2-methoxyphenol [19]. 

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