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Experimental and kinetic study on the transesterification of ethyl acetate with Methanol catalyzed by gel and macroporous acidic ion exchange resins

Evelien Van de Steene (UGent) , Jeriffa De Clercq (UGent) and Joris Thybaut (UGent)
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Abstract
The reaction kinetics of the liquid-phase transesterification of ethyl acetate with methanol have been investigated over a series of commercially available ion-exchange resins. Two morphology types of cross-linked polymer resins have been considered, i.e., a gel type (Lewatit K1221) and a macroporous type (Lewatit K2640, Lewatit K2629 and Amberlyst 15). The effect of the swelling of the resin, the initial reactant molar ratio (1:1 – 10:1) and the temperature (303.15 – 333.15 K) on the reaction kinetics was experimentally assessed. Lewatit K1221, the gel-type resin, outperformed the macroporous-type resins, despite its similar number of sulfonic acid sites. The resin’s swelling behavior, which can be related to its degree of cross-linking with divinylbenzene, was identified as the key parameter to explain differences in acid site accessibility between the considered resins and, hence, the observed transesterification kinetics. A fundamental kinetic model, accounting for the chemical elementary steps as well as for the physical swelling due to solvent absorption, was constructed to quantitatively assess the experimental observations. According to this model (1) all active sites are occupied by methanol in protonated form, (2) the esters undergo a proton exchange with the protonated methanol and (3) the reaction occurs through an Eley-Rideal mechanism with the surface reaction of protonated ethyl acetate with methanol from the bulk as the rate-determining step. The kinetic model was able to adequately describe the entire experimental data set. An activation energy amounting to 49 kJ mol-1 was obtained, irrespective of the resin. Also the affinity of each of the resins for the esters was found to be similar. The differences in catalytic activity between the considered resins are found back in the values for the rate coefficients and, hence, can be brought into relation with the active site accessibility. The latter is a factor 3 to 4 higher for gel-type resins compared to macroporous-type resins. An independent experimental assessment of the resins’ swelling behavior confirmed the more pronounced swelling of the gel-type compared to the macroporous-type resins.
Keywords
kinetics, swelling, transesterification, ion-exchange resins, cross-linking, heterogeneous catalysis

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Chicago
Van de Steene, Evelien, Jeriffa De Clercq, and Joris Thybaut. 2013. “Experimental and Kinetic Study on the Transesterification of Ethyl Acetate with Methanol Catalyzed by Gel and Macroporous Acidic Ion Exchange Resins.” In XIth European Congress on Catalysis, Abstracts, 217–217.
APA
Van de Steene, E., De Clercq, J., & Thybaut, J. (2013). Experimental and kinetic study on the transesterification of ethyl acetate with Methanol catalyzed by gel and macroporous acidic ion exchange resins. XIth European Congress on Catalysis, Abstracts (pp. 217–217). Presented at the XIth European Congress on Catalysis (EuropaCat XI).
Vancouver
1.
Van de Steene E, De Clercq J, Thybaut J. Experimental and kinetic study on the transesterification of ethyl acetate with Methanol catalyzed by gel and macroporous acidic ion exchange resins. XIth European Congress on Catalysis, Abstracts. 2013. p. 217–217.
MLA
Van de Steene, Evelien, Jeriffa De Clercq, and Joris Thybaut. “Experimental and Kinetic Study on the Transesterification of Ethyl Acetate with Methanol Catalyzed by Gel and Macroporous Acidic Ion Exchange Resins.” XIth European Congress on Catalysis, Abstracts. 2013. 217–217. Print.
@inproceedings{3109880,
  abstract     = {The reaction kinetics of the liquid-phase transesterification of ethyl acetate with methanol have been investigated over a series of commercially available ion-exchange resins. Two morphology types of cross-linked polymer resins have been considered, i.e., a gel type (Lewatit K1221) and a macroporous type (Lewatit K2640, Lewatit K2629 and Amberlyst 15). The effect of the swelling of the resin, the initial reactant molar ratio (1:1 -- 10:1) and the temperature (303.15 -- 333.15 K) on the reaction kinetics was experimentally assessed. Lewatit K1221, the gel-type resin, outperformed the macroporous-type resins, despite its similar number of sulfonic acid sites. The resin{\textquoteright}s swelling behavior, which can be related to its degree of cross-linking with divinylbenzene, was identified as the key parameter to explain differences in acid site accessibility between the considered resins and, hence, the observed transesterification kinetics.
A fundamental kinetic model, accounting for the chemical elementary steps as well as for the physical swelling due to solvent absorption, was constructed to quantitatively assess the experimental observations. According to this model (1) all active sites are occupied by methanol in protonated form, (2) the esters undergo a proton exchange with the protonated methanol and (3) the reaction occurs through an Eley-Rideal mechanism with the surface reaction of protonated ethyl acetate with methanol from the bulk as the rate-determining step. The kinetic model was able to adequately describe the entire experimental data set. An activation energy amounting to 49 kJ mol-1 was obtained, irrespective of the resin. Also the affinity of each of the resins for the esters was found to be similar. The differences in catalytic activity between the considered resins are found back in the values for the rate coefficients and, hence, can be brought into relation with the active site accessibility. The latter is a factor 3 to 4 higher for gel-type resins compared to macroporous-type resins. An independent experimental assessment of the resins{\textquoteright} swelling behavior confirmed the more pronounced swelling of the gel-type compared to the macroporous-type resins.},
  author       = {Van de Steene, Evelien and De Clercq, Jeriffa and Thybaut, Joris},
  booktitle    = {XIth European Congress on Catalysis, Abstracts},
  language     = {eng},
  location     = {Lyon, France},
  pages        = {217--217},
  title        = {Experimental and kinetic study on the transesterification of ethyl acetate with Methanol catalyzed by gel and macroporous acidic ion exchange resins},
  year         = {2013},
}