Hydrogen saturation capacity

The apparent saturation capacity of an oxide surface for hydrogen adsorption at a given temperature and the large change to a new apparent saturation at another temperature, facts familiar to all who have studied the slow sorption processes on oxides, should be re-studied in reference to Volkenstein s assumption that the sites available for adsorption, the thermal sites, vary with temperature. On this view the measurements of Shou-Chu Liang and the writer would gain new significance. In brief, measurements of slow sorption on oxide surfaces need to be... 

The temperature programmed desorption (t.p.d) of n-hexane from the sodium and hydrogen forms of ZSM-5. ZSM-11 and THETA-1 have been studied. The t.p.d profiles have been analysed by a newly developed method. From these analyses peak temperatures, peak widths, maximum rates of desorption and activation energies of desorption as a function of coverage have been obtained. The saturation capacities of these high silica zeolites for n-hexane have also been determined. The effect of change of cation on all of these quantities is demonstrated. 

The preference for isomerization can be attributed to the moderate hydrogen sorption capacity due to contaminants to the acidic medium and to the high dispersity of the catalyst. Under these conditions, p-phase palladium hydride, which can be active in C=C double bond hydrogenation, may be absent. Saturation by hydrogen of dispersed palladium in an acidic medium at 1 bar results in a-hydride phase formation only (8). An a-p phase transformation in 0.05 mol dm- Na2S04 demands a higher pressure than predicted by the Pd-H solubility diagram (4) or a considerable increase in the saturation time up to 15-20 days, especially in the presence of contaminants. 

Fig. 6.10 Correlation between saturation hydrogen storage capacity and specific surface area of the adsorbent at 77 K [31].

Each isomer has its individual set of physical and chemical properties however, these properties are similar (Table 6). The fundamental chemical reactions for pentanes are sulfonation to form sulfonic acids, chlorination to form chlorides, nitration to form nitropentanes, oxidation to form various compounds, and cracking to form free radicals. Many of these reactions are used to produce intermediates for the manufacture of industrial chemicals. Generally the reactivity increases from a primary to a secondary to a tertiary hydrogen (37). Other properties available but not Hsted are given in equations for heat capacity and viscosity (34), and saturated Hquid density (36). 

Hydrolysis of D-(+)-1 (3-methoxyphenyl)-2-aminopropane 2.42 mols (40 g) of the compound are dissolved In 8N hydrochloric acid in a bomb tube consisting of stainless steel and having a capacity of 500 ml. Hydrogen chloride gas is passed into the ice-cooled solution until this is saturated. The solution is then heated to 130°C for 2 hours in an air bath. After cooling and driving off the hydrochloric acid at a slightly elevated temperature, the hydrochloride of the 3-hydroxyphenyl derivative is present in the form of a yellowish syrup. 

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