Structural transformation and chemical modifications of the unusual layered zeolite MWW form SSZ-70

MWW and MFI Frameworks as Model Layered Zeolites: Structures, Transformations, Properties, and Activity

“…These higher values are quite rare since many authors report that both 2D MWW and 2D MFI structures show lower intensities of the Si-OH-Al maximum at 3610−3620 cm −1 than their 3D counterparts even for a similar Si/Al ratio. 76,237,250 Notably, the analysis of layered zeolites is more complex considering the significant increase in surface effects and potential defects. One of these unusual effects results from the apparent presence of acidic groups, which are capable of protonating pyridine but do not contribute to the intensity of IR maximum at 3610−3620 cm −1 (Figure 6a,b) and therefore remain undetected by FTIR.…”

“…However, upon swelling with surfactants, the regular offset of layers in SSZ-70 becomes obliterated, and the product becomes similar to other swollen MWWs, as shown by XRD. 76 MCM-56, an MWW zeolite with a high Al content obtained by direct synthesis, shows advantages in swelling with surfactants, in contrast to the precursor MCM-22P, whose swelling decreases with the increase in Al content. 75 These are isolated observable differences, and it remains to be seen if they are general.…”

“…Hierarchy factor (HF) plotted in a contour plot as a function of the relative mesoporous surface area and relative microporous volume of different zeolite types prepared using different methods (from ref ) and adding 2D MFI and MWW (data presented in Table ). Colors: violet–ref , dark green–ref , green–ref , dark blue–ref , red–ref , magenta–ref , orange–ref , yellow–ref . Individual colors are also given in Table .…”

An asymmetric Salamo-based Zn complex supported on Fe3O4 MNPs: a novel heterogeneous nanocatalyst for the silyl protection and deprotection of alcohols under mild conditions

“…Therefore, these parts, or groups, must be protected. [1][2][3][4] Regarding the number of protection and deprotection groups, it is highly signicant to consider and reconsider the chemistry applied in unnatural structures and also in the building of nature's architecturally beautiful and diverse molecular frameworks. Usually attached to the asymmetrically substituted carbon atom, the hydroxyl group can be regarded as the most fundamental functional group in organic chemistry.…”

Recent advances in catalytic silylation of hydroxyl‐bearing compounds: A green technique for protection of alcohols using Si–O bond formations

“…[1][2][3][4] In this sense, a wide variety of protective groups have been developed. [4][5][6][7][8] There are different requirements which must be fulfilled by a protective group [9][10][11][12][13] ; including the following: (1) In order to have a protected substrate, it must selectively react in good yield [14] ; (2) it should be selectively removed in good yield by available, nontoxic reagents by which the regenerated functional group is not attacked [15,16] ; (3) it must form a derivative being able to be separated from side products related to its formation or cleavage [17,18] ; and (4) with the aim of avoiding more sites of reaction, it must possess a minimum of additional functionality. [19] Moreover, one should pay attention to the fact that no protective group is the best protective group.…”