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Controlled methylamine synthesis in a membrane reactor featuring a highly steam selective K+-LTA membrane
Publikationstyp
Journal Article
Date Issued
2022-05
Sprache
English
Author(s)
Mundstock, Alexander
Richter, Hannes
Hindricks, Karen D. J.
Huang, Aisheng
Behrens, Peter
Caro, Jürgen
Volume
337
Article Number
111920
Citation
Microporous and Mesoporous Materials 337: 111920 (2022)
Publisher DOI
Publisher
Elsevier BV
Water permeation through a hydrophilic zeolite membrane can be used to promote reactions under equilibrium controlled conditions through the in situ removal of the by-product water. In the methylamine synthesis, mono-(MMA), di- (DMA) and trimethylamine (TMA) are formed by the successive methylation of ammonia with methanol (MeOH) over a mildly acidic catalyst. The methylamine yield can be increased through selective water extraction from the reactor through a membrane. Since both reactants and water have similar molecular kinetic diameters below 3.7 Å, because of the limited steam selectivity of the commonly used hydrophilic Na-LTA membrane (zeolite 4A), not only water has been removed. Therefore, in this work a K-LTA membrane, which was obtained by ion exchange with a reduced pore window diameter of 3 Å and thus with a higher water selectivity, was used in the membrane-supported methylamine synthesis. When replacing the Na-LTA with the KLTA membrane, the H2O/MeOH mixed gas separation factor increases up to 1100 and the H2O/NH3 separation could also be improved. This in turn leads to an overall boost of the higher methylated amines DMA and TMA in methylamine synthesis. When using the narrow-pore aluminosilicate catalyst H-SSZ-13 with CHA structure, the
application of the K-LTA membrane increases the share of the industrially desired product DMA from 51% without membrane to 74% with slightly increased conversion. When using the large-pore catalyst H-MOR, the thermodynamically most stable product TMA can be formed and the selectivity was increased from 35% without membrane to 41% with the K-LTA membrane.
application of the K-LTA membrane increases the share of the industrially desired product DMA from 51% without membrane to 74% with slightly increased conversion. When using the large-pore catalyst H-MOR, the thermodynamically most stable product TMA can be formed and the selectivity was increased from 35% without membrane to 41% with the K-LTA membrane.
DDC Class
540: Chemistry