Dimethyl ether carbonylation over nanosheet-assembled hierarchical mordenite.

Abstract In this paper, a series of hierarchical MOR catalysts were synthesized by using PEG as templates. The structural and acid properties of obtained MOR catalysts were systematically investigated by XRD, N 2 adsorption-desorption, SEM, NH 3 -TPD and DME-TPD. The characterization results showed that the crystallinity of the MOR catalysts nearly doubled with the addition of PEG molecules. The specific surface area and total pore volume increased on the hierarchical MOR catalysts and showed a strong dependence on the PEG molecular weight. Compared with the reference sample, the specific surface area and total pore volume increased by 80.3 m2 g−1 and 0.017 cc. g−1 respectively when using PEG-6000 as template. The strong acid sites slightly increased and the amount of DME adsorption also increased due to the combined effect of hierarchical structure and increasing amount of strong acid sites. The mass transfer efficiency in the hierarchical MOR catalyst was largely improved after the introduction of mesopores. The catalytic activity and stability of hierarchical MOR catalysts grudally increased with the PEG molecular weight. The single-pass lifespan over the PEG-6000 sample was 1.6 times of that on the reference sample. The amount of coke deposition over the deactivated hierarchical MOR catalysts gradually increased. Nevertheless, the H/C ratio of coke deposition increased as the space limitations of mesopores to the coke depositions were less obvious compared with micropores. Graphical abstract Image 1 Highlights • Hierarchical MOR were synthesized by using PEG as templates. • Mesopores concentrated around 2.5 nm were introduced by PEG molecules. • The mass transfer efficiency was largely enhanced due to the mesopores. • The carbonylation performance and stability of MOR were both improved. [ABSTRACT FROM AUTHOR]