Additions and corrections
Pseudomorphic synthesis of mesoporous zeolite Y crystals
Robin Chal, Thomas Cacciaguerra, Sander van Donk and Corine Gérardin
Chem. Commun., 2010, 46, 7840–7842 (DOI: 10.1039/c0cc02073g) Amendment published 21st March 2011
At the request of the editor, we would like to communicate this addition that serves to clarify the following two points:
1. Identification of the new aspects of the current work in relation to its similarity to earlier published work on the topic.
2. The state of the art related to this topic.
1. The experimental procedure described here is similar to that of Example 1 from Ying's patent5 and uses the same concentration and temperature conditions. As in the patent, the nitrogen adsorption isotherms obtained at 77 K show a high initial uptake due to the zeolite micropores and a sharp nitrogen uptake above P/P0 = 0.3 characteristic of mesoporous materials. As in the patent, a microporous/mesoporous material is obtained, as shown by XRD patterns and TEM images. In the present case, instead of an hexagonal MCM-41 structure, a HMS vermicular structure is formed, with only one XRD peak characterizing the mesostructure around 2° 2θ. The mesopore size is also higher, centred at 4.3 nm according to the NLDFT method, and the XRD peak gives an inter-reticular distance of 45.8 Ĺ. In the present paper, the occurrence of a pseudomorphic synthesis is revealed by electron microscopy images of the zeolite Y modified by recrystallisation. The crystalline zeolite lattice is similar to that observed in the parent zeolite by TEM, but interruptions of that structure are evidenced due to the presence of mesopores, as described in Ying's patent.5 A new result is brought by the acidity measurements, which were done by NH3 temperature programmed desorption and exhibited almost the same total acidity before and after recrystallisation. Finally, elemental analysis showed that the recrystallisation process involves neither desilication nor dealumination since the final Si/Al ratio remains the same.
2. The state of the art concerning the recrystallisation route of zeolites was incomplete. The correct version is:
In 2004, Ivanova et al.1 reported a simple synthesis approach to generate extra-porosity by recrystallisation of zeolite MOR in a NaOH solution in the presence of a mesopore templating agent, later extended to BEA zeolite.2–4 These materials were micro/mesoporous composites based on zeolite single crystals with secondary mesoporous structure and mesoporous materials composed of tiny zeolitic species, and exhibited high catalytic activity, stability, and selectivity in the transformation of bulky molecules.
Also in 2004, Ying and Garcia Martinez et al.5 submitted a patent application describing a route to produce mesostructured zeolites with intracrystalline mesoporosity zeolites (FAU, MFI, MOR) using different alkaline sources (NaOH, NH4OH, and TMAOH) in the presence of a surfactant. The patent was issued in 2005, and related patents followed.6–8
In 2005, Wang et al.9 reported the synthesis of a MOR/MCM-41 composite with better accessible acid sites than the parent zeolite.
1. I. I. Ivanova, A. S. Kuznetsov, V. V. Yuschenko and E. E. Knyazeva, Pure Appl. Chem., 2004, 76, 1647–1658.
2. I. I. Ivanova and E. E. Knyazeva, RU Pat., 2006, 2288034.
3. V. V. Ordomsky, V. Y. Murzin, Y. V. Monakhova, Y. V. Zubavichus, E. E. Knyazeva, N. S. Nesterenko and I. I. Ivanova, Microporous Mesoporous Mater., 2007, 105, 101–110.
4. V. V. Ordomskii, Y. V. Monakhova, E. E. Knyazeva, N. S. Nesterenko and I. I. Ivanova, Russ. J. Phys. Chem. A, 2009, 83, 1012–1017.
5. J. Y. Ying and J. Garcia-Martinez, US Pat., 20050239634, 2005, Proskauer Rose LLP.
6. J. Garcia-Martinez, WO Pat., 2006031259, 2006, Massachusetts Inst. Technology.
7. J. Garcia-Martinez, US Pat., 20080138274, 2008, Rive Technology Inc.
8. J. Garcia-Martinez and M. M. Johnson, US Pat., 2009, 20090110631, Rive Technology Inc.
9. S. Wang, T. Dou, Y. Li, Y. Zhang, X. Li and Z. Yan, Catal. Commun., 2005, 6, 87–91.
The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.
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