Nickel-kieselguhr

Isomerization of sorbitol, D-mannitol, L-iditol, and dulcitol occurs in aqueous solution in the presence of hydrogen under pressure and a nickel—kieselguhr catalyst at 130—190°C (160). In the case of the first three, a quasiequiUbrium composition is obtained regardless of starting material. Equilibrium concentrations are 41.4% sorbitol, 31.5% D-mannitol, 26.5% L-iditol, and 0.6% dulcitol. In the presence of the same catalyst, the isohexides estabUsh an equihbrium at 220—240°C and 15.2 MPa (150 atm) of hydrogen pressure, having the composition 57% isoidide, 36% isosorbide, and 7% isomannide (161). 

Butanol, reaction over reduced nickel oxide catalysts, 35 357-359 effect of ammonia, 35 343 effect of hydrogen, 35 345 effect of pyridine, 35 344 effect of sodium, 35 342, 351 effect of temperature, 35 339 over nickel-Kieselguhr, 35 348 over supported nickel catalysts, 35 350 Butanone, hydrogenation of, 25 103 Butene, 33 22, 104-128, 131, 135 adsorption on zinc oxide, 22 42-45 by butyl alcohol dehydration, 41 348 chemisorption, 27 285 dehydrogenation, 27 191 isomerization, 27 124, 31 122-123, 32 305-308, 311-313, 41 187, 188 isomerization of, 22 45, 46 isomers... 

Neopentyl alcohol (continued) effect of pyridine, 35 344 effect of sodium, 35 342 effect of temperature, 35 339, 341 mechanism, 35 347 over nickel-kieselguhr, 35 348 Nemst s law, 40 117 Neutral ligands... 

Fig. 13. Variation of the differential heat of chemisorption of hydrogen on nickel-kieselguhr calculated from magnetic measurements. Relative magnetization (

Raney nickel (Am. Soc., 54,4116) is particularly reactive for hydrogenation in the liquid phase at low temperatures and pressures, whilst nickel-kieselguhr (loc. dt. 1651) is suitable for various types of hydrogenation at high pressures. 

Morikawa (100) and also Koizumi (101) found that the polymerization of ethylene proceeds rapidly in the presence of a nickel-kieselguhr catalyst containing 15% Ni, while both nickel or kieselguhr alone are extremely poor catalysts of this reaction. This might be interpreted by the presence of active sites localized at the interface of nickel and kieselguhr since the formation of a homogeneous new phase between these two components is improbable. 

The reaction of ethylene with deuterium has been studied using nickel wire 30, 43-45), nickel-kieselguhr 27, 32, 46) and evaporated nickel films 42, 47) as catalysts. The use of differing temperatures and differing partial pressure ratios makes a comparison between them difficult. 

Deuterobutane DittrUnUions from the Reaction of Bvienee with a Tenfold Excess of Deuterium over Nickel-Kieselguhr... 

In an effort to obtain a less temperature-sensitive system, lower nickel content catalysts were prepared on an alumina support and tested for demethylation activity. The first, Preparation A, with a nominal nickel content of 50 wt % was activated at 700°F in a slow stream of hydrogen at atmospheric pressure for 16 hours. This catalyst was tested at conditions similar to those employed with the nickel-kieselguhr catalyst reported above. The results are given in Table II. 

As may be seen from examination of these data, results are very similar to those obtained with the nickel-kieselguhr catalyst. The catalyst... 

Once near steady-state activity had been reached (19 hours), the temperature was decreased 15 °F, and the effect of decreased temperature on conversion and selectivity established, Run 4. An estimated activation energy for the conversion of methylcyclohexane is 28 kcal/mole, only 2 kcal less than the approximate value for the nickel-kieselguhr catalyst. The effect of decreased operating pressure is shown by the data of Run 5. Conversion increased, and efficiency to cyclohexane decreased slightly. The same effect was noted previously in fixed bed tests with Preparation A. 

A plot of In k" vs. 1/T for the nickel-kieselguhr catalysts is shown in Figure 2. The activation energy for the reaction is estimated at 30 kcal/mole. As mentioned earlier, this value was confirmed substantially by data taken during Period 4 of the fluidized-bed run (Table IV) where temperature control was better. In this run 28 kcal/mole was obtained despite the difference in catalyst composition. 

The following nickel-carrier catalysts have been described nickel-kieselguhr,169 nickel-pumice,170 nickel-kieselguhr containing thorium oxide,171 nickel on magnesium oxide, barium oxide, or beryllium oxide,172 nickel on aluminum oxide,173 and nickel-zinc oxide-barium oxide-chromium oxide.174 Other carriers for nickel catalysts are active charcoal, silica, fuller s earth, and oxides such as magnesia, alumina, and bauxite. 

Copper can also be used as a catalyst, like nickel, alone, on carriers, or as a mixed catalyst with metals of the first to the eighth Group of the Periodic Table. The temperature needed for reduction of the catalyst, usually containing the copper as oxide, hydroxide, or basic carbonate, is 150-300°. Preparation of a copper-kieselguhr catalyst is similar to that of a nickel-kieselguhr catalyst.175... 

This paper deals with the synthesis of propionic acid by the reaction of carbon monoxide, ethylene, and water and with the synthesis of iso-butyric acid and 2-methylbutyric acid, respectively, by the reaction of carbon monoxide with n-propyl alcohol and ra-butyl alcohol. Using equimolar amounts of carbon monoxide and ethylene in the presence of a nickel-kieselguhr (30 70) catalyst, a yield of 40.5% of propionic acid was obtained after two hours at 180° and 3500-psig. pressure. With a nickel iodide-silica gel (Ni Si02 = 50 50) catalyst for the reactions of carbon monoxide and alcohols, conversions up to 82.4% in the case of n-propyl alcohol and 92.8% in the case of n-butyl alcohol were obtained. The effect of the different operating variables on the reactions and the peculiarities of the catalysts have been studied and are discussed. 

Nickel-kieselguhr catalysts with or without a small percentage of magnesia and thoria These catalysts were prepared by precipitation of the metals as carbonates from the solutions of their nitrates holding a suspension of B.D.H. kieselguhr. The carbonates were subsequently decomposed to the oxides in a current of air and the nickel reduced by hydrogen at 300°. 

Synthesis of Propionic Acid by the Reaction of Carbon Monoxide, Ethylene, and Water Catalyst Nickel-kieselguhr (30 70). Reactants CO C2H4 = 1 1. Reaction temperature, 180°. Water 1.389 g. moles. Reaction period, 2 hrs. 

A. Nickel-Kieselguhr Catalyst It was prepared by precipitating nickel carbonate from a hot solution of nickel nitrate by hot potassium carbonate solution in presence of kieselguhr, washing and drying the mass, and reducing it in situ in the reaction bomb itself by a stream of hydrogen at 300-350°. 

Fig. 11. Rate of adsorption of Hj on clean surface of nickel kieselguhr (Du Pont).

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