Organic phases methylated hydrocarbon

In the petroleum (qv) industry hydrogen bromide can serve as an alkylation catalyst. It is claimed as a catalyst in the controlled oxidation of aHphatic and ahcycHc hydrocarbons to ketones, acids, and peroxides (7,8). AppHcations of HBr with NH Br (9) or with H2S and HCl (10) as promoters for the dehydrogenation of butene to butadiene have been described, and either HBr or HCl can be used in the vapor-phase ortho methylation of phenol with methanol over alumina (11). Various patents dealing with catalytic activity of HCl also cover the use of HBr. An important reaction of HBr in organic syntheses is the replacement of aHphatic chlorine by bromine in the presence of an aluminum catalyst (12). Small quantities of hydrobromic acid are employed in analytical chemistry. 

The next step in purification is separation of uranyl nitrate from the other metallic impurities in the dissolver solution by solvent extraction. Practically aU uranium refineries now use as solvent tributyl phosphate (TBP) dissolved in an inert hydrocarbon diluent. The first U.S. refinery used diethyl ether as solvent and later refineries have used methyl isobutyl ketone or organic amines, but practically all have now adopted TBP. It is nonvolatile, chemically stable, selective for uranium, and has a uranium distribution coefficient greater than unity when the aqueous phase contains nitric acid or inorganic nitrates. 

Fig. 9.1. (A) Chromatogram of a ten

Zeolites are clays with rather large internal pore structures which have the property of concentrating nonpolar organic compounds within their cavities. Measurements of gaseous hydrocarbon equilibria have shown enhancements of several orders of magnitude within zeolite pores relative to the vapor phase. Cyclodimerization of butadiene to 4-vinylcyclohexene (Equation 7.5) at 250°C was catalyzed by large-pore zeolites in the sodium form (Dessau, 1986). Zeolites in the Cu(I) form also promoted Diels-Alder addition of furan and other dienes with electron-deficient dienophiles such as methyl vinyl ketone (Equation 7.6). Dichloro-methane was the solvent in these reactions, which usually were carried out at 0°C or lower (Ipaktschi, 1986). 

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