Synthesis, characterisation and physicochemical properties of polyphenols prepared by cobalt(II) catalysed oxidative polymerisation
✍ Scribed by A. Puzari; Jubaraj B. Baruah
- Publisher
- Elsevier Science
- Year
- 2000
- Tongue
- English
- Weight
- 230 KB
- Volume
- 46
- Category
- Article
- ISSN
- 1381-5148
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✦ Synopsis
The catalytic reaction of Co (DAM) Cl with phenolic compounds such as phenol, p-cresol, o-cresol, m-cresol etc. in the 2 7 4 presence of hydrogen peroxide gave C-O bonded oligomers (1-4). The oligomers were characterised by NMR, IR, elemental analysis. The M values of 1-4 were 3417, 3494, 3438 and 3550, respectively. The oligomers contain OH end n groups. The oligomer 1 has resistance profile such that it increases to 508C and then falls exponentially in the region of 50 to 1708C. The resistance of 2 and 4 are similar to semiconductor in the range of 30-1808C. The oligomer 3 has a resistance profile such that it decreases from 30 to 1008C and then increases from 100 to 1408C and once again falls in the region of 140-2008C. The oligomer 4 has an esr signal at 3220 G and shows the presence of a free radical. The intensity of this signal increases ten times upon heating to 908C.