Template decomposition

Ni [182], V [183], and A1 [184]. SU-M [185] is a mesoporous germanium oxide with crystalline pore walls, possessing one of the largest primitive cells and the lowest framework density of any inorganic material. The channels are defined by 30-rings. Structural and thermal information show that there exists a mismatch between framework stability and template decomposition. The latter requires temperatures higher than 450 °C, while the structure is preserved only until 300 °C. 

Furthermore, investigations of template decomposition in zeolites upon calcination of the as-synthesized materials have received much attention by researchers (248-250). However, the decomposition mechanisms of quaternary ammonium salts, which are commonly used as templates for zeolite synthesis, are still not well understood. Thus, MAS NMR investigations of the decomposition of quaternary ammonium ions in zeolites bear the potential of significantly improving the understanding of these processes (243,251). For this purpose, a general method was developed for the synthesis of... 

Effect of O2 on the Template Decomposition in SAPO Molecular Sieves... 

Figure 1 Template decomposition in Argon-l and Air-2 in SAPO-5 (A) SAPO-37 (B) and SAPO-34 (C)...

Acidity and Catalytic Activity of In-SAPO Obtained via Template Induced RSSIE The template decomposition in SAPO s goierates proton acidity that was characterized... 

The study was conducted on sample Si-0.16. The experiments with NaCl or La(N03>3 solutions at room temperature or 400 K give either no exchange or amorphisation of the materials. After exchange with a NH4NO3 solution at a pH of 4 the X ray diffraction does not detect a change in the sample crystallinity. The unit cell parameter is decreased from 24.76 ( 0.01) A to 24.65 ( 0.01) A. A similar modification was already observed after the template decomposition upon heating at 875 K (2). 

The problem here was that the target molecule is very complex and unstable. The results of the rebinding test are shown after 1 and 26 h of equilibration (expressed as peak area values). The absolute absorbance decreased during this time due to template decomposition. 2-Vinyl pyridine appeared to be the most successful monomer based on the equilibrium batch rebinding tests (Fig. 15). The 2-VPY materials prepared on a larger scale and tested as chromatographic stationary phases also exhibited a certain selectivity towards the template (methotrexate, MTX) and its closely related analogues (leucovorin and folic acid) (Fig. 16). 

J. Y. Luo et al synthesized the mesoporous La-Co-Ce-O composit oxide by citric acid complexation-organic template decomposition method. The catalysts prepared by this method had a high specific surface area about 95-156.6 m. g with very uniform pore diameter (3.7-3.95 nm) (changing with the different component and calcination temperature). The catalysts were used in catalytic CO oxidation and propane oxidation, and the excellent catalytic properties and thermal stability can be observed. In the case of CO oxidation, the reaction temperatures for 50% (Tso) and 90% CO (Tgo) conversion are 140 °C and 169 °C, respectively, over mesoporous La-Co-Ce-0 eomposit oxide catalysts, which are 39 and 30 lower than those over the catalyst prepared by co-preeipitation method (LCC (0.5)-CP-500 catalyst) in the case of propane oxidation, the 301 °C and 341 °C reaction temperature are required for the Tso and Tgo, which are 29 and 64 lower than those over the LCC (0.5)-CP-500 catalyst. In addition, the ordered mesoporous strueture of catalyst was conductive to the dispersion and transmission of the reactants, and therefore the inner surface of catalyst was fully utilized, which benefited the increase in catalytic activity and efficiency by the easy accessibility, and as well as the decrease in resistance of mass-transfer. As a result, excellent catalytic properties for CO oxidation and propane oxidation can be obtained over mesoporous lanthanum-containing composite oxide catalysts [87],... 

Luo, J. Meng, M. Qian, Y. et al. Mesoporous Mixed Oxide La-Co-Ce-0 Catalysts Prepared by Citric Acid Complexation-Organic Template Decomposition Method. Chin J. Catal. 2006, 27(6), 471-473. 

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