Kinetics of Alkali-Catalyzed Monomethylol Phenol Formation for F/P < 1 by 1H NMR Spectroscopy for Ablative Applications

The formation of monomethylol phenols and their ratio during the polymerization reaction of phenol ( P ) and formaldehyde ( F ) dictate the final product and thereby formulated composite properties. Here, we have studied the kinetics of ortho- and para-methylol phenol formation during the polymeriza...

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Bibliographic Details
Published in:Transactions of the Indian National Academy of Engineering (Online) 2021-03, Vol.6 (1), p.147-152
Main Authors: Solasa, Praveen Kumar, Saraswathi Kesava Pillai, Manu, Kumar, Vijendra, Alex, Ancy Smitha, Chinthalapalli, Srinivas, Retnakumari Amma, Sadhana, Nair, C. P. Reghunadhan
Format: Article
Language:English
Subjects:
Engineering
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Summary:The formation of monomethylol phenols and their ratio during the polymerization reaction of phenol ( P ) and formaldehyde ( F ) dictate the final product and thereby formulated composite properties. Here, we have studied the kinetics of ortho- and para-methylol phenol formation during the polymerization ( F / P  = 0.89) under alkaline conditions (pH 7.3–7.8) at 60, 70, 80 and 90 °C using 1 H NMR spectroscopy. 13 C NMR validated the results obtained. On increasing reaction temperature, reactant consumption rate and ratio of ortho- to para-methylol phenol ( o / p ) formation increased. The o / p also increased with an increase in reaction time for all the temperatures studied. The reaction follows pseudo-first-order kinetics with respect to formaldehyde. The activation energies of the addition reaction between phenol and formaldehyde and the formed prepolymers are determined. Thus, 1 H NMR appears handy in studying the kinetics of prepolymers formed.
ISSN:2662-5415
2662-5423
DOI:10.1007/s41403-021-00202-5