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Kinetics of hydroxymethyl phenols formation by in‐line FTIR spectroscopy
Author(s) -
Poljanšek Ida,
Likozar Blaž,
Krajnc Matjaž
Publication year - 2007
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.26791
Subject(s) - formaldehyde , phenol , sodium hydroxide , chemistry , order of reaction , hydroxide , hydroxymethyl , kinetics , activation energy , fourier transform infrared spectroscopy , phenols , inorganic chemistry , reaction rate constant , organic chemistry , chemical engineering , physics , quantum mechanics , engineering
The kinetics of phenol–formaldehyde prepolymers catalyzed by sodium hydroxide at various temperatures was studied. Several reactions were conducted with different phenol to formaldehyde as well as phenol to sodium hydroxide molar ratios. The React‐IR system was used to monitor the reaction as well as to determine residual free phenol and formaldehyde. The changes in the concentrations of phenol and formaldehyde with the reaction time were determined. The value of the concentration of the hydroxide ion, [OH − ], was obtained by measuring the pH value of reaction mixture. The concentration of the hydroxide ion, [OH − ], expressed as a function of reaction time, was fitted by the six‐order polynomial to the experimental data. On the basis of the proposed reaction scheme the kinetic model was developed. The kinetic parameters were obtained by adjusting the experimental evolution of phenol and formaldehyde during the synthesis. Using this method the changes in the concentrations of five species of hydroxymethyl phenols with the reaction time was also been calculated. The activation energy and preexponential factor have been calculated for individual reactions. The accuracy of the kinetic model was confirmed by comparing experimental concentration profiles of formaldehyde and phenol with the calculated ones for different molar ratios. The experimental tendencies are in agreement with the results of the model. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007