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Nickel alumina catalyst

The formation of trace amounts of 2,2 -bipyridine following reaction between pyridine and ammonia in the presence of a variety of catalysts led Wibaut and Willink to develop a method for the preparation of 2,2 -bipyridine from pyridine under the influence of a nickel-alumina catalyst. Using a pyridine-to-catalyst ratio of 10 1, temperatures between 320° and 325°C, and pressures between 42 and 44 atm, 2,2 -bipyridine was formed in yields of 0.30-0.67 gm per gram of catalyst. This method w as later applied to -picoline, to quino-line, - and to some of its derivatives, ... [Pg.180]

Reaction of -picoline with a nickel-alumina catalyst has been reported to give a mixture of four isomeric dimethylbipyridines, one of which has been identified at 6,6 -dimethyl-2,2 -bipyridine. With palladium-on-carbon, 2,4-lutidine was found to be more reactive than pyridine,and the isolated biaryl has been assigned the structure (2). However, some confusion arises from the statement that this... [Pg.182]

With nickel/alumina catalysts (cf. 4 ) preparation by coprecipitation or by the decomposition of a high dispersion of nickel hydroxide on fresh alumina hydrogel, yields nickel aluminate exclusively. On the other hand, when, as in impregnation, larger particles of nickel compound are deposited, the calcination product is a mixture of nickel oxide and nickel aluminate. The proportion of nickel oxide increases when occlusion of the impregnation solution leads to a very nonuniform distribution (49). [Pg.13]

Morikawa et al. (42) suggest that nickel aluminate itself undergoes hydrogen reduction only to a superficial extent, and then produces extremely small nickel particles as the reduction product. In this circumstance, the nickel particle size distribution in a reduced nickel/alumina catalyst will obviously be much dependent on the preparative details that control the proportions nickel oxide and nickel aluminate and the size of the particles in which these substances exist before reduction. [Pg.14]

CRG [Catalytic Rich Gas] A process for making town gas and rich gas from light petroleum distillate (naphtha). The naphtha is reacted with steam over a nickel-alumina catalyst yielding a gas mixture rich in methane. Developed by British Gas and used in the United Kingdom in the 1960s, but abandoned there after the discovery of North Sea gas. In 1977,13 plants were operating in the United States. [Pg.74]

Garcia, L., Sanchez, J.L., Salvador, M.L., Bilbao, R., and Arauzo J. (1996). Hydrogen-rich Gas from Steam Gasification of Biomass Using Coprecipitated Nickel-alumina Catalysts, Bioenergy 96. The Seventh National Bioenergy Conference, pp. 859-865. [Pg.141]

As in the synthesis of other bipyridines, several routes to 4,4 -bipyridine have been devised where one of the pyridine rings is built up from simpler components. For example, a dimer of acrolein reacts with ammonia and methanol in the presence of boron phosphate catalyst at 350°C to give a mixture of products including 4,4 -bipyridine (3.4% yield), and in a reaction akin to ones referred to with other bipyridines, 4-vinylpyridine reacts with substituted oxazoles in the presence of acid to give substituted 4,4 -bipyridines. ° ° Condensation of isonicotinaldehyde with acetaldehyde and ammonia at high temperatures in the presence of a catalyst also affords some 4,4 -bipyridine, and related processes give similar results,whereas pyran derivatives can be converted to 4,4 -bipyridine (56% conversion), for example, by reaction with ammonia and air at 350°C with a nickel-alumina catalyst. Likewise, 2,6-diphenyl-4-(4-pyridyl)pyrylium salts afford 2,6-... [Pg.328]

The following example illustrates one particular quantitative application of compensation behavior for the comparison of levels of activity between different systems. The Arrhenius parameters for the steam reformation reaction over nickel alumina catalysts (290) are log A = 17.25 and E = 29.0. The position of this point on compensation diagrams would appear to be more realistically represented by the compensation relation found for oxidation and exchange processes on nickel oxide (Table V, G) than that for cracking on the metal (Table I, A). One possible mechanistic explanation for this distinction is that the active catalyst is an oxide phase [possibly including NiAl204 (290)1... [Pg.304]

Kruissink, E.C., Van Reijen, L.L. and Ross, J.R.H. (1981) Coprecipitated nickel—alumina catalysts for mefhanation at high temperature. Part 1. Chemical composition and structure of the precipitates. J. Chem. Soc., Faraday Trans. 1, 77, 649. [Pg.180]

K. Tanaka, T. Miyazaki and K. Aomura, Intermediates and carbonaceous deposits in the hydiogenolysis of ethane on a nickel-alumina catalyst, J. Catal. 81(2) (1983) 328-334,... [Pg.170]

S. D. Jackson, S. S. Thompson and G. Webb, Carbonaceous deposition associated with the catalytic steam-refortning hydrocarbons over nickel alumina catalysts. J. Catal, 70 (1981) 249-263,... [Pg.171]

We shall consider first the nature of the carbonaceous species produced by propane decompoeition on the nickel/ -alumina catalyst. From TEM, this was found to be filamental in nature. The mechanism of the growth of these filaments is proposed to involve diffusion of carbon through a metal particle and eventual precipitation at the rear of the metal crystallite (Kef 3,A). [Pg.184]

This model satisfactorily explains the propane TPRn profile obtained on the nickel/ -alumina catalyst (Figure 1). Dehydrogenation of propane was initially observed at 240 C and then shoved a gradual increase in rate until a temperature of 350 C was attained. Over this temperature range, the surface... [Pg.184]

The objectives of this research were (1) to investigate the effects of initial controlled-pH level of Ni(N03)2 solution, alkali and alkaline earth metal, and transition metal upon catalyst resistance to coke formation and (2) to establish relationships between coking rate and peak temperatures of TPD and TPH spectra of nickel-alumina catalysts. [Pg.254]

Fig. 1 Temperature-programnicd descKption spectra of unpromoted and promoted nickel-alumina catalysts. Fig. 1 Temperature-programnicd descKption spectra of unpromoted and promoted nickel-alumina catalysts.
Formation Rate of Carbon Deposit for Unpromoted and Promoted Nickel-Alumina Catalysts. [Pg.256]

Chen, I.W. Chen, F.L., Effect of Alkali and Alkaline-Earth Metals on the Resistivity to Coke Formation of and Sintering of Nickel-Alumina Catalysts, Ind. Eng. Chem. Res, 1990, 29, 534-539. [Pg.257]

Dissanayake, D., Rosynek, M.P., Kharas, K.C.C., and Lunsford, J.H. Partial oxidation of methane to carbon monoxide and hydrogen over a nickel/alumina catalyst. Journal of Catalysis, 1991, 132, 117. [Pg.152]

Flguie A13. Phases of nickel compounds present after calcination of nickel alumina catalysts. [Pg.111]


See other pages where Nickel alumina catalyst is mentioned: [Pg.155]    [Pg.288]    [Pg.373]    [Pg.110]    [Pg.23]    [Pg.44]    [Pg.51]    [Pg.431]    [Pg.3]    [Pg.254]    [Pg.254]    [Pg.255]    [Pg.257]    [Pg.257]    [Pg.65]    [Pg.164]    [Pg.358]    [Pg.115]    [Pg.3]    [Pg.254]   
See also in sourсe #XX -- [ Pg.223 , Pg.228 , Pg.266 , Pg.267 , Pg.270 , Pg.272 , Pg.417 , Pg.418 , Pg.426 , Pg.429 , Pg.442 ]

See also in sourсe #XX -- [ Pg.139 ]

See also in sourсe #XX -- [ Pg.86 , Pg.95 , Pg.101 ]




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