Sunday 8 January 2017

Improving the efficiency of the Diels-Alder process by using flow chemistry and zeolite catalysis

Improving the efficiency of the Diels-Alder process by using flow chemistry and zeolite catalysis


Green Chem., 2017, 19,237-248
DOI: 10.1039/C6GC02334G, Paper
S. Seghers, L. Protasova, S. Mullens, J. W. Thybaut, C. V. Stevens
The industrial application of the Diels-Alder reaction for the synthesis of (hetero)cyclic compounds constitutes an important challenge. To tackle the reagent instability problems and corresponding safety issues, the use of a high-pressure and zeolite catalysed microreactor process is presented.





Improving the efficiency of the Diels–Alder process by using flow chemistry and zeolite catalysis

S. Seghers,a   L. Protasova,b   S. Mullens,b  J. W. Thybautc and   C. V. Stevens*a  
*Corresponding authors
a
SynBioC Research Group, Department of Sustainable Organic Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium
 E-mail: chris.stevens@ugent.be
b
VITO, Vlaamse Instelling voor Technologisch Onderzoek, Boeretang 200, 2400 Mol, Belgium
c
Laboratory for Chemical Technology, Department of Chemical Engineering and Technical Chemistry, Faculty of Engineering and Architecture, Ghent University, Technologiepark 914, 9052 Ghent, Belgium
Green Chem., 2017,19, 237-248

DOI: 10.1039/C6GC02334G



























http://pubs.rsc.org/en/Content/ArticleLanding/2017/GC/C6GC02334G?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract


The industrial application of the Diels–Alder reaction for the atom-efficient synthesis of (hetero)cyclic compounds constitutes an important challenge. Safety and purity concerns, related to the instability of the polymerization prone diene and/or dienophile, limit the scalability of the production capacity of Diels–Alder products in a batch mode. To tackle these problems, the use of a high-pressure continuous microreactor process was considered. In order to increase the yields and the selectivity towards the endo-isomer, commercially available zeolites were used as a heterogeneous catalyst in a microscale packed bed reactor. As a result, a high conversion (≥95%) and endo-selectivity (89 : 11) were reached for the reaction of cyclopentadiene and methyl acrylate, using a 1 : 1 stoichiometry. A throughput of 0.87 g h−1during at least 7 h was reached, corresponding to a 3.5 times higher catalytic productivity and a 14 times higher production of Diels–Alder adducts in comparison to the heterogeneous lab-scale batch process. Catalyst deactivation was hardly observed within this time frame. Moreover, complete regeneration of the zeolite was demonstrated using a straightforward calcination procedure.







//////Diels-Alder,  flow chemistry, zeolite catalysis

No comments:

Post a Comment