Controlled methylamine synthesis in a membrane reactor featuring a highly steam selective K⁺-LTA membrane

verfasst von

Felix Rieck genannt Best, Alexander Mundstock, Hannes Richter, Patrick A. Kißling, Karen D.J. Hindricks, Aisheng Huang, Peter Behrens, Jürgen Caro

Abstract

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 K-LTA 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.

Organisationseinheit(en)

Institut für Physikalische Chemie und Elektrochemie
Institut für Anorganische Chemie
PhoenixD: Simulation, Fabrikation und Anwendung optischer Systeme
Laboratorium für Nano- und Quantenengineering

Externe Organisation(en)

Fraunhofer-Institut für Keramische Technologien und Systeme (IKTS)
East China Normal University
South China University of Technology

Typ

Artikel

Journal

Microporous and Mesoporous Materials

Band

337

ISSN

1387-1811

Publikationsdatum

05.2022

Publikationsstatus

Veröffentlicht

Peer-reviewed

Ja

ASJC Scopus Sachgebiete

Chemie (insg.), Werkstoffwissenschaften (insg.), Physik der kondensierten Materie, Werkstoffmechanik

Elektronische Version(en)

https://doi.org/10.1016/j.micromeso.2022.111920 (Zugang: Geschlossen)