Prehydrogenation

It is known that hydrogen incorporated into Si subsequently exposed to ionizing radiation inhibits the formation of induced secondary point defect (Pearton and Tavendale, 1982a). For example, in both Si and Ge a number of electron or y irradiation induced defect states appear to be vacancy-related, and exposure of the Si or Ge to a hydrogen plasma (or implantation of hydrogen into the sample) prior to irradiation induces a degree of 

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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. 

The feedstocks were prehydrogenated real gas oil fractions with different aromatic, sulphur and nitrogen contents from Hungarian and Russian crudes. Their important properties are summarized in Table 2. 

A noteworthy feature of the Seager-Anderson experiment was that after hydrogenation of a diode it could be restored practically to its prehydrogenation state by heating for 10 minutes at 200°C. This process of hydrogenation and dehydrogenation could be repeated many times, producing the same sequence of C-V profiles each time. 

Reduction of Nitrobenzenes. Nitrobenzene was injected in small increments into 200 ml. of prehydrogenated (258 ml. of H2) cyanocobaltate(II) solution (0.15M cobalt, GN/Co = 5.1). After an induction period of approximately 4 minutes, hydrogen absorption commenced ... 

Reactions with Hydrido Complex. Upon injection of a prehydrogenated cyanocobaltate(II) solution (0.15M cobalt, CN/Co = 6.0) into an atmosphere of butadiene, the gas was rapidly absorbed, 0.92 mole of butadiene being taken up for each hydrogen atom previously absorbed. Similarly, when the injection was made into a butadiene-saturated cyanocobaltate(II) solution in a butadiene atmosphere, 1.08 moles of butadiene were absorbed. These results provide evidence of the addition of butadiene to the hydrido complex in the following manner ... 

Nitrobenzene. Observations made on the formation of cyanocobaltate(II) in the presence of excess nitrobenzene, and on the addition of an excess of this substrate to the prehydrogenated complex, were identical to those made with benzoquinone as the substrate. However, a difference was noted when less than stoichiometric quantities of nitrobenzene were added. After a short induction period of approximately 4 minutes, hydrogen absorption commenced, 3.3 atoms of hydrogen being absorbed per mole of substrate (no absorption occurred with benzoquinone in the absence of added alkali). Further additions of small incre-... 

The 850°F+ conversion is a correlating parameter for comparing C1-C4 gas yield, C5-500°F liquid yield, 500°F+ conversion, and 650°F+ conversion. Various combinations of the operating parameters of space velocity, total reactor pressure, and temperature achieve the same 850°F+ conversion. Thus, the product distribution can then be related to 850°F+ conversion with only minor variations between specific experimental runs. No difference in product distribution (at a given 850°F+ conversion) was noted for runs made with SRC-I/prehydrogenated KC-Oil at 70/30 and 50/50 nominal weight ratio feed blends. 

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

Prehydrogenation of bitu- Splitting hydrogenation minous-coal middle oil of petroleum gas oil... 

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.

It is not believed that the results are influenced to any noticeable extent by higher interior temperature of the larger pellets. If this had been the case, greatly increased hydrocarbon gas formation in prehydrogenation as well as splitting experiments would have been expected. In addition, this effect should have been more pronounced in prehydrogenation because of the greater heat of reaction. 

Temperature of Prehydrogenation Reactions with JUSs Catalyst... 

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. 

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

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