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Authors :
Cesar Augusto Moraes de Abreu
G. Descotes
N. M. Lima Filho
C. F. Braga
Y. Queneau
Source :
Reaction Kinetics and Catalysis Letters. 77:91-102
Publication Year :
2002
Publisher :
Springer Science and Business Media LLC, 2002.

Abstract

The process of sucrose esterification in the presence of a homogeneous catalyst was developed directing the reaction to the production of weakly substituted esters. Esterification of sucrose was processed with octanoyl chloride in a discontinuous reactor, in presence of 4-dimethylaminopyridine as catalyst. The process was operated in a time interval ranging from 0 to 80 min, at temperatures from 288 to 303 K, pH=10 and at atmospheric pressure. The following conversion levels were obtained: octanoyl chloride 11-84%, primary monoester production of 9-67%, secondary monoesters of 1.3-17%. Activation energies ranging from 158 l to 300 kJ/mol characterized the stages of the process, among them the stage of formation of the DMAP/RCOCl complex (162.43 kJ/mol). The increase in primary monoesters yield due to the temperature rise, leads to an increase in the rate of the direct reaction as well as in the speed of secondary monoester conversion to primary monoesters, quantifying a selectivity in primary isomers in the following positions sequence: 6> 1" > 6".

Details

ISSN :
01331736
Volume :
77
Database :
OpenAIRE
Journal :
Reaction Kinetics and Catalysis Letters
Accession number :
edsair.doi...........4824955831e78ad1aef15fd9a4451de2
Full Text :
https://doi.org/10.1023/a:1020395904204