Prehydrogenation catalysts

With the introduction of the two-stage vapor-phase operation in 1935, the WS2 catalyst was used at first as a prehydrogenation catalyst. The cost of this catalyst and the properties shown in Table VIII were the reasons for the development of other prehydrogenation catalysts. The data in Table VIII were derived from experiments for the prehydrogenation of bituminous-coal middle oil at 250 atm. hydrogen pressure and a throughput of 0.8 kg. of feed/liter of catalyst. 

Fig. 11. Mo-Ni prehydrogenation catalysts supported on activated alumina. Components I. Ni203. II. M0O3. III. Mo03 with constant 20 g./liter Ni203.

Fig. 12. Influence of Ni content on alumina-supported Mo and W prehydrogenation catalysts. I. 150 g. MoOa/liter constant. II. 250 g. Wo03/liter constant.

Fia. 15. Iron and cobalt as a substitute for nickel in the Al2Oj-WS2-NiS(70-27-3) prehydrogenation catalysts. O-----Co-Ni combination. A-------- Fe-Ni com-... 

Over platinum oxide the yield of isocoronopilin varied from 63 to 100%, depending on whether or not the catalyst was prehydrogenated (92). Minor... 

This Crude product (15.8 g) In water (360 ml) was added to a prehydrogenated suspension of 10% palladium on charcoal (4 g) in water (400 ml), and hydrogenation was continued for 30 minutes. The catalyst was removed and the filtrate was adjusted to pH 7.5 with sodium bicarbonate, then evaporated at low temperature and pressure. The residue was purified by chromatography on a column of cellulose powder, eluting first with butanol/ ethanol/water mixture and then with acetone/isopropanol/water. The main fraction was evaporated at low temperature and pressure to give a 32% yield of the sodium salt of a-carboxybenzylpenicillin as a white powder. The product was estimated by manometric assay with penicillinase to be 58% pure. 

Prehydrogenation and Splitting Experiments with IV/Sj Catalysts of Different Sizes at 250 Atm. Pressure and 0.85 Kg. of Feed/ Kg. Catalyst) (Hr.)... 

For the splitting hydrogenation of petroleum gas oil, a lower temperature than that required for the prehydrogenation of bituminous-coal middle oil with smaller conversion to gasoline was sufficient. This is caused mainly by the higher nitrogen content of the bituminous-coal middle oil, which decreases catalyst activity. As shown in Table IV, aromatic rings like naphthalene are saturated with WS2 catalyst at a temperature of 335°C. 

Fig. 10. Influence of WS2 catalyst size on aniline points of prehydrogenation product fractions.

Temperature of Prehydrogenation Reactions with JUSs Catalyst... 

Practically complete removal of nitrogen compounds is needed for the splitting catalyst. Therefore, a prehydrogenation temperature above that... 

Vapor-phase hydrogenation results and experimental evidence of this type lead to the conclusion that catalysts on basic supports are suitable for nonsplitting prehydrogenation-type reactions and that acidic supports are best used for splitting catalysts. Activated alumina was found to be the best support because of rapid reduction of tar acids. Especially, alumina precipitated from aluminum salts at constant pH was satisfactory and produced catalysts that could be formed into pellets of high mechanical strength. 

The first suitable activated-alumina catalyst contained 10% M0O3 activated by addition of 3% nickel oxide. This catalyst was superseded by a more active tungsten catalyst containing 70% activated alumina, 27% tungsten sulfide, and 3% nickel sulfide. This catalyst is used in commercial plants for the prehydrogenation of middle oils and also for the direct hydrogenation of shale oil and lignite tar (TTH process). 

The influence of varying amounts of the active component in Mo-Ni catalysts on alumina is shown in Fig. 11. The prehydrogenation tests were made with a bituminous-coal middle oil (aniline point—12°C., 17% tar acids, 0.75% N2) with the addition of 1% CS2. Carbon bisulfide is... 

In the same experiments the degree of hydrogenation of the middle oil has been determined. Figure 14 is a graph of the aniline point of the prehydrogenation middle oil (180° to 325°C.) for the four catalysts at varying temperatures. The aniline point increases with reaction temperature... 

Comparison of these results with those reported for prehydrogenation shows that the selectivity of these catalysts for sulfur removal has been... 

The properties of gasolines (40) from various liquid-phase-hydrogenation middle oils obtained by prehydrogenation and splitting hydrogenation with the fuller s earth-WS2 catalyst are shown in Table XVII for gasolines of about 190°C. end point and with 40% boiling up to 100°C. 

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