Measurement of p‑Toluenesulfonic Acid-Catalyzed Reaction Kinetics of 1,2-Propylene Glycol Acetylation Using In Situ 1H NMR Spectroscopy

The reaction kinetics for the acetylation of 1,2-propylene glycol (PG) catalyzed by p-toluenesulfonic acid (p-TSA) were determined using an in situ 1H NMR method. Both primary and secondary monoacetate esters of PG were observed as well as the diester. The reaction kinetics were characterized as a f...

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Bibliographic Details
Published in:Industrial & engineering chemistry research 2013-07, Vol.52 (27), p.9337-9342
Main Authors: Santhanakrishnan, Arati, Peereboom, Lars, Miller, Dennis J, Dumitrascu, Adina, Smith, Patrick B
Format: Article
Language:English
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Summary:The reaction kinetics for the acetylation of 1,2-propylene glycol (PG) catalyzed by p-toluenesulfonic acid (p-TSA) were determined using an in situ 1H NMR method. Both primary and secondary monoacetate esters of PG were observed as well as the diester. The reaction kinetics were characterized as a function of PG to acetic acid (AA) stoichiometry, p-TSA concentration, and temperature. The acetylation reactions and the transacetylation of the diester with PG were modeled as reversible second order reactions. Equilibrium constants were determined experimentally for each reaction. Activation energies for the consecutive acetylation of PG and PG monoacetate ester (PGMA) were 56 and 47 kJ/mol, respectively. The activation energy for intermolecular transacetylation of PG with its diacetate ester to form PG monoacetate was 63 kJ/mol.
ISSN:0888-5885
1520-5045
DOI:10.1021/ie400045v