Title
Reactor design for the Novozym 435R-catalysed enantioselective esterification of 4-methyloctanoic acid
Author
Heinsman, N.W.J.T.
van der Weide, P.L.J.
van der Padt, A.
Franssen, M.C.R.
Boom, R.M.
van 't Riet, K.
Centraal Instituut voor Voedingsonderzoek TNO
Publication year
2002
Abstract
The bench scale Novozym 435® catalysed esterification of 4-methyloctanoic acid with ethanol was studied at 35°C. Esterification in a batch reactor (molar ratio of 1:8 (acid:EtOH)) resulted in the isolation of the enantiomerically enriched product (eep = 81%) and substrate (ees = 93%). In order to integrate reaction and separation, liquid-vapour equilibria calculations were performed showing that an excess of ethanol results in a very low ester fraction in the vapour phase. Since this is undesirable for an integrated process of reaction and product removal, a repeated batch reaction was performed using a moular ratio of 10:1 (acid:EtOH). After six cycles (45% conversion) the ee of 4-methyloctanoic acid ethyl ester turned out to be 80%. For different E values the eep was calculated for batch and repeated batch reactions. It was shown that in all cases the eep was higher for the repeated batch reaction. However, the product is not enantiopure since the E value of the reaction is rather low at the low ethanol concentration used. An alternative approach would be the continuous separation of the product during the reaction. A mathematical model was developed to describe esterification in a packed bed reactor integrated with product separation. This model shows that integration of reaction and product removal in advance is not suitable either to obtain an enantiomerically pure product. Since the optimal reaction conditions (high ethanol concentration) and the optimal separation system (low ethanol concentration) do not match in this reaction, the preference is given to the batch reaction at high ethanol concentrations because in that case the highest enantioselectivity of the enzyme is obtained. Chemicals/CAS: alcohol, 64-17-5
Subject
Nutrition
Batch reaction
Branched chain fatty acids
Kinetic resolution
Lipase
Reactor design
Repeated batch
Carboxylic acids
Enzymes
Esterification
Esters
Ethanol
Mathematical models
Stereochemistry
Batch reactors
Catalysis
To reference this document use:
http://resolver.tudelft.nl/uuid:3ca97e61-d912-495c-8c62-07e8788a3870
DOI
https://doi.org/10.1080/1024242021000040864
TNO identifier
57619
ISSN
1024-2422
Source
Biocatalysis and Biotransformation, 20 (6), 429-436
Document type
article