Phenolic compounds, abiotic polymerization

Wang,T.S.C. Huang, P.M. Chang-Hung Chou Jen-Hshuan Chen (1986) The role of sod minerals in the abiotic polymerization of phenolic compounds and formation of humic substances. In Huang, P.M. Sdmitzer, M. 

Source Modified with permission from Wang,T. S. C., Huang, P. M., Chou, C.-H., and Chen, J.-H. (1986). The role of soil minerals in abiotic polymerization of phenolic compounds and formation of humic substances. In Interactions of Soil Minerals with Natural Organics and Microbes, Huang, P. M., and Schnitzer, M., eds., SSSA Special Publ. No. 17, Soil Science Society of America, Madison, WI, 251-281. 

A kinetic model is presented by Pohlman and McColl (1989) to describe the initial and rapid redox processes between polyhydroxyphenolic acid and soil or Mn oxide suspensions. The oxidation process of polyhydroxybenzoic acid by soil and Mn oxides follows second-order kinetics. The rate constants derived from the model are similar in magnitude in both suspensions for the organic reductants studied (Table 8-16). Polyhydroxyphenolic acids with para- and ortho-OH groups are rapidly oxidized by Mn oxides with spectral evidence suggesting that the reaction leads to polymeric humic products probably via semiquinone or benzoquinone derivatives. By contrast, polyhydroxyphenolic acids with meta-oriented phenolic-OH groups are not oxidized by soil or Mn oxide suspensions within a 120-min reaction period. Presumably these compounds are not capable of being oxidized to semiquinone or benzoquinone intermediates. The rapid disappearance of polyhydroxyphenolic acids is accompanied by formation of Mn and colored humic products in both soil and Mn oxide suspensions. These results provide further evidence that abiotic oxidation of certain organics can lead to the formation of humic substances and the mobilization of Mn in nature. 

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