Omega hydrogen

Preparation and Use of Dual-Function Catalysts Based on Hydrogen-Omega... 

A study is presented of the synthesis and properties of the novel synthetic zeolite omega. The synthesis variables and kinetics of formation are discussed, as well as the ion exchange, sorption, and thermal properties. By decomposition of imbibed tetra-methylammonium ions and exhaustive treatments of the zeolite with ammonium ions, a pure hydrogen form can be obtained which is a suitable substrate for the preparation of hydrocarbon conversion catalysts. Several catalysts were prepared and utilized to isomerize n-hexane, and to hydrocrack a heavy gas oil. 

Of these heavier atoms, uranium is the heaviest, so that together with hydrogen, the lightest, we may think they both surround all elements of the universe, including those that constitute the Earth, ourselves and the items of our daily life. Hydrogen and uranium are this sort of alpha and omega that Mother Nature invented to energise our universe and to support the development of life. 

Commercial hydroisomerization catalysts have both a noble metal based hydrogenating function and an acid function (Table 7.3). Traditionally, the acid component is provided by (i) a zeolite or by (ii) a chlorinated alumina substrate or by (iii) a sulfated zirconia carrier, the latter both being extremely intolerant of sulfur, water, and other feed contaminants. The zeolite is generally a mordenite and not a Y-zeolite. However, catalysts based on zeolite omega have been shown to be superior to mordenite-based catalysts, but no up-scale to commercial use has been reported for omega zeolite containing hydroisomerization catalysts (see below). 

Methanesulphonic acid is an efficient catalyst for cyclizing omega-acetal side-chains on to ring-carbon atoms. An alternative method which gives comparable yields is to warm the acetal at about SO °C for 4 h in a solvent which is saturated with hydrogen chloride. 

Nickelocene hydrogenated onto an omega zeolite support with promoter comprising an oxide of Ni, Fe, and/or Cu... 

A combination of X-ray photoelectron and infrared spectroscopy, where both techniques employed pyridine as a probe, was used by Borade and Clearfield [492] when they tested the acidity of a series of zeolites. All of their samples contained strong Bronsted sites, weak Bronsted sites and Lewis sites. With respect to the Bronsted acid strength of the hydrogen forms these authors arrived at the following sequence H-Omega>H-Beta>H-ZSM-22>H-mordenite>H-Y. 

M. A. Bednarek, J. P. Springer, B. R. Cunningham, A. M. Bemick, M. Bodanszky, Reactions of C-terminal omega-amino acid residues in bquid hydrogen fluoride. Int. J. Pept. Protein Res. 1993, 42, 10-13. 

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