Y faujasite

Soda Y Zeolite is a crystallized form of Y-faujasite before any ion exchanges occur. 

Ultra Stable Y is a hydrothermally treated Y-faujasite which has a unit cell. size at or below 24.50 °A and exhibits superior hydrothermal stability over Soda Y faujasite. 

The concept of extractive reaction, which was conceived over 40 years ago, has connections with acid hydrolysis of pentosans in an aqueous medium to give furfural, which readily polymerizes in the presence of an acid. The use of a water-immiscible solvent, such as tetralin allows the labile furfural to be extracted and thus prevents polymerization, increases the yield, and improves the recovery procedures. In the recent past an interesting and useful method has been suggested by Rivalier et al. (1995) for acid-catalysed dehydration of hexoses to 5-hydroxy methyl furfural. Here, a new solid-liquid-liquid extractor reactor has been suggested with zeolites in protonic form like H-Y-faujasite, H-mordenite, H-beta, and H-ZSM-5, in suspension in the aqueous phase and with simultaneous extraction of the intermediate product with a solvent, like methyl Aobutyl ketone, circulating countercurrently. 

Samples of Y faujasites were prepared by sodium exchange of a starting ultrastable Y zeolite (H form, denoted in the following as USY). Global Si/Al ratio is 16 according to X fluorescence measurements framework Si/Al is 21 as measured by 29Si MAS NMR. 

J.-F. Chapat, A. Finiels, J. Joffre, and C. Moreau, Synthesis of butyl-a and / -d-glucopyranosides in the presence of dealuminated H-Y faujasites Kinetic study, mechanism, stereoelectronic effects, and microreversibility principle, /. Catal., 185 (1999) 445—453. 

Erising, T. and Leflaive, P. (2008) Extraframework cation distributions in X and Y faujasite zeolites a review. Micropor. Mesopor. Mat., 114, 27-63. 

Recently, the PER of phenyl acetate and phenyl benzoate has been studied within zeolites of the faujasite and pentasil families, which are structurally very different. [277,278] It was found that for phenyl acetatet in faujasites X and Y, the predominating product is the ortho isomer, whereas in the pentasils ZSM-5 and ZSM-11, the preferred product is the para isomer. These differences have been explained taking into account the different sizes and shapes of the cavities and channels of the two families. The faujasites are made up of channels of 8 A diameter, leading to supercages of 13 A diameter, where the reaction is expected to occur, whereas the pentasils are made up of narrow channels of 6 A diameter. In the X and Y faujasites, the ortho position would be favored due to the restricted mobility, whereas in the channels of ZSM-5 and ZSM-11, there would be a shape limitation because the ortho isomer does not fit but the para isomer does (Table 15). With phenyl benzoate inside X or Y zeolites, the same... 

Zeolites have attracted much attention as cobalt catalyst supports ]151-155]. Co2(CO)8 reacts rapidly from the vapor phase with X and Y faujasite type zeolites Co4(CO)i2, subcarbonyl species and [Co(CO)4] species form inside the pores. Further migration of Co4(CO)i2 carbonyl is inhibited because of pore size hmita-tions, and subsequent decarbonylation can take place only above 150 °C. In contrast, the reaction of Co2(CO)g with an A-type zeolite is limited to the surface due to the inability of the carbonyl precursors to pass through the apertures of the cavities of the structure. 

Co2(CO)g has been used to obtain encapsulated cobalt clusters in Y-faujasite, which have been used as model catalysts for methane homologation [152]. The gas phase adsorption of Co2(CO)8 under N2 rendered predominately encaged Co4(CO)i2 species whereas Co,s(CO)iis was obtained when the impregnation of Co2(CO)8 was carried out under a CO/H2 atmosphere [152, 155], Samples were oxidized at 80°C, subsequently reduced at 400 °C and then structurally characterized by EXAFS. Clusters of two and three cobalt atoms were formed from encaged Co4(CO)i2 and COis(CO)iis, respectively. Higher methane conversion and selectivity to C2+ products in the CH4 homologation reaction have been obtained for the two atoms-size cluster sample the results were discussed using a DFT model [152]. 

Al Quadrupole Coupling Constant, C-rjcc. ond Asymmetry Parameter, tj, of Framework Al Atoms in Dehydrated Zeolites Y (faujasite), MOR (mordenite), and ZSM-5... 

Therefore, it seems that tridireotional zeolites HY and HB are the most promi sing ones for liquid phase reactions. In the case of HB zeolites, two items deserve special comments. Firstly, the yield (82%) of ethyl phenylacetate for the equimolar esterification of phenylacetic acid and ethanol in the presence of the fl-10 sample is substantially higher than that of the equilibrium (69%) at the same temperature and solvent (Table 3). Analogous results have been already observed with dealuminated acidic Y faujasites and can be due to zeolite water adsorption and/or to the hydrophobicity of the in surfaces (ref. 2). The hydrophobic character of high silica... 

Both reactions of alkynes and nitriles were studied over mordenite, B and Y-faujasite type zeolites in their H-form. 

Figure 5a. Three-dimensionally connected system of large and small cages in zeolite Y (faujasite) showing 1,1,2,2-tetrabromoethane inside a large cage.

Although several methods have been reported in recent literature concerning the preparation of 5-hydroxymethylfurfural by dehydration of fructose, we have shown that microporous catalyts in their protonic form, for instance, Mordenites, Beta, Y-faujasites and ZSM-5 zeolites constituted a convenient alternative route to the catalysts used up to now, namely mineral acids, oxides or ion-exchange resins/27,281... 

Breck s preparation of type Y faujasite in die late 1950 s still stands as the outstanding success in zeolite synthesis (2). Type X might have had some catalytic applications but I doubt the International Zeolite Association would exist without the interest and support generated by the catalytic applications of the Type Y materials. It didn t seem that critical at the time after all Breck had reproduced a material which exists naturally. Synthetic counterparts of natural zeolites have been prepared dozens of times since (3). But die extra silica content, or perhaps die diminished alumina content, was enough to give high temperature stability in the acid form and to get zeolites into catalysts for petroleum processes (4). 

ECR-1 crystallizes in the presence of DHEDM and DHPDM from gels which would normally yield Y-faujasite in the absence of any organic template. The best products crystallized in the composition range with Si/Al between 3 and 6, at temperatures between 120°C and 160°C, using a seed nucleant solution (IS.). Synthesis of DHEDM ECR-1 was made from a gel stoichiometry of ... 

AN ORIGINAL BEHAVIOUR OF COPPER(II)-EXCHANGED Y FAUJASITE IN THE RUFF OXIDATIVE DEGRADATION OF CALCIUM GLUCONATE... 

Copper(II)-exchanged Y Faujasite in the Ruff Oxidative Degradation of Calcium Gluconate... 

The effect of dealumination can be observed in a series of commercial Y-faujasites with Si Al ratios of 2.6, 5.8, 12.8 and 24. The modification of the acidity resulting from the dealumination is illustrated by the curves of differential heats of ammonia adsorphon (Figure 9.16). 

J. W. Ward (Union Oil Co. of California, Brea, Calif. 92621) Could you detect platinum by x-ray diffraction on the Y faujasite catalysts ... 

I. M. Keen We have detected little platinum in fresh Y faujasite catalysts by x-ray diffraction techniques. Preliminary investigations by other techniques—e.g., electron microscopy, hydrogen chemisorption— have, however, suggested the presence of some largish crystallites of platinum, presumably on the surface/edges of the zeolite base crystals. 

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