Faujasitic catalysts

We find from separate e qperiments with ZSM-5 catalyst that the intrinsic rate constant for isomerization, kj, is much faster than that for disproportionation, kD at 482°C, kj/kD > 7000, i.e. kj/kD is much faster than it is for the synthetic faujasite catalyst. 

These results represent the first ever reported evidence of strict cooperation between the steric requisites of the faujasite catalyst and the reactivity of an asymmetrical carbonate, in simultaneously inducing high methyl chemoselectivity and mono-A-methylselectivity for primary amines. 

Kebulkova, L., Novakova,)., Jaeger, N.I., and Schultz-Ekloff, G. (1993) Characterization of nickel species at Ni/7-Al203 and Ni/faujasite catalysts by carbon monoxide adsorption. Appl Catal. A,... 

Selective hydroxylation of phenol with hydrogen peroxide was reported on acid zeolite catalysts [91-92]. Peroxonium ions, formed by H2O2 protonation, are the oxidizing species. When the reaction is carried out on a faujasite catalyst, a mixture of hydroxybenzenes and tars is obtained [91]. In the presence of H-ZSM-5 on the other hand, no tar formation was mentioned (which does not necessarily mean that it was absent) and p-selectivities close to 100% were reported for the hydroxylation [92]. These superior selectivities reflect the shape selective properties of ZSM type zeolites. 

Ultrastable faujasitic catalysts are a cornerstone of the petroleum industry, and it is not surprising that much effort has been devoted to the study of their properties amd methods of preparation. The following summarizes the most important observations ... 

This paper documents compositional analyses obtained for FCC gasolines produced over two commercially produced and available faujasite catalysts with and without the addition of ZSM-5 additive. 

Two conventional faujasite catalysts commercially produced and available were used in this study, catalyst A, which contains about three percent rare earth and catalyst B which contains almost zero rare earth and significantly more zeolite (as measured by X-ray crystallinity) than catalyst A. 

The conventional faujasite catalysts were steamed at 1400 F in 2 atmospheres steam at varying times in order to achieve the same activity as measured by our standard Fluid Activity Index (FAI). Table I summarizes the steaming conditions employed. 

The ZSM-5 additive used in the study was commercially available and contains 25% ZSM-5 zeolite in an inert matrix. The ZSM-5 additive was steamed at conditions (8) chosen to simulate the activity of a commercially equilibrated REX cracking catalyst (Table I). Eight weight percent of the additive was then blended with each faujasite catalyst (two weight percent ZSM-5 zeolite). 

HAMDAN AND KLINOWSKI Secondary Synthesis of Faujasitic Catalysts 449... 

Quadrupole Nutation NMR Studies of Second Generation Faujasitic Catalysts... 

We present some recent results obtained in the Princeton University Chemistry Department on the nature of the active center in catalysts derived from sodium type faujasite catalyst (17, 18, 23, 25, 26, 27, 28, 29, 30, 31). A general survey of the structural characteristics has been given by one of us and by others (1, 4, 9, 25, 33). 

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. 

Figure 2. i-C4/n-C4 ratios in n-hexane cracking over faujasitic catalysts. 

The study of alkylation by methanol on a series of faujasite catalysts and a series of Na zeolites with different structures has been shown that the... 

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