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Kinetics and mechanism of oligomerization of cardanol using acid catalysts
Author(s) -
Manjula S.,
Kumar V. G.,
Pillai C. K. S.
Publication year - 1992
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1992.070450213
Subject(s) - trimer , tetramer , chemistry , dimer , monomer , kinetics , cardanol , catalysis , polymer chemistry , reaction rate constant , proton nmr , reaction mechanism , resonance (particle physics) , yield (engineering) , photochemistry , organic chemistry , polymer , materials science , quantum mechanics , epoxy , metallurgy , enzyme , physics , particle physics
Abstract The kinetics and mechanism of oligomerization of cardanol over acid catalysts were studied. GPC results showed the formation of a mixture of oligomers such as dimer, trimer, tetramer, etc. IR spectra of the products of oligomerization showed a decrease in the intensity of the double bond absorption band at 1630 cm −1 and the disappearance of terminal vinyl bands at 895 cm −1 and 907 cm −1 . 1 H NMR spectra showed drastic changes in the unsaturated proton resonance signals at 5.5δ with respect to saturated protons at 0.2–2.5δ. The ratio of resonance integrals of unsaturated to saturated protons decreased from 1 : 6.5 to 1 : 20 after oligomerization. GPC studies showed that the rate of formation of the dimer, trimer, tetramer, etc. follow an identical path and that the individual oligomers are formed in the same weight percentage at any time during the reaction. A kinetic scheme is proposed to explain this phenomenon. Kinetic studies showed that the oligomerization reaction follows first order kinetics with respect to the monomer concentration and the rate constant is K = 6.6 × 10 −5 s −1 . A probable mechanism for the oligomerization of cardanol is proposed.