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AljOj catalysts

Selective Reduction of NO by Propene over Au/y-AljOj Catalysts... [Pg.701]

Zn/AljOj catalysts, 31 249 -Zn/Cr Oj catalysts, 31 250 -ZnO/AljO, 31 276, 292-295 -ZnO binary catalyst, 31 257-287 activity patterns, 31 271-274 BET argon surface areas, 31 259 calcination, 31 261-262 catalytic testing, 31 272 chemisorption, 31 268-271 CO2 effects, selectivity, 31 284-285 color spectra, 31 259-261 component comparison, 31 258-259 methanol synthesis, 31 246-247 modifiers, weakening of adsorption energy, 31 283... [Pg.81]

AljOj catalysts, metal dispersion, 39 240 -amine complexes, COj reduction, 28 142 -carbon monoxide adsorption, 28 4, 6 energy, 28 15 structure, 28 10, 14 desorption, 28 23 as catalyst... [Pg.191]

Dehydrogenation of ethylbenzene to styrene. FejOj/AljOj catalyst pellets (occasionally potasium doped) packed on tube side of the reactor. [Pg.128]

The anion vacancy sites have acid properties. As stated above, the catalytic activity and the hydrogenolytic behavior correlated with the acid properties of the catalyst, as well as the extent of reduction. Therefore, the adsorption of an aryl group will occur on the coordinatively unsaturated molybdenum sites generated during reduction. According to the reaction scheme for the hydrogenation of ethylene over a reduced MoOj-AljOj catalyst, ethylene becomes it-bonded at a second vacant ligand position of a coordinatively unsaturated Mo species and inserts to form the [Pg.267]

Fig. 3. Yields of heptadienes and aromatics from 1-heptene, as a function of the amount of Ni/AljOj catalyst. Pulse system, carrier gas He (x) aromatics (O) heptadienes. (a) T = 355 C (b) T = 370°C (c) T = 390 C (50). Fig. 3. Yields of heptadienes and aromatics from 1-heptene, as a function of the amount of Ni/AljOj catalyst. Pulse system, carrier gas He (x) aromatics (O) heptadienes. (a) T = 355 C (b) T = 370°C (c) T = 390 C (50).
Catalytic hydrogenation seldom breaks unactivated C—C bonds (i.e., R—R + H2 — RH + R H), but methyl and ethyl groups have been cleaved from substituted adamantanes by hydrogenation with a Ni-AljOj catalyst at about 250°C.517 Certain C—C bonds have been cleaved by alkali metals.518... [Pg.634]

Fig. 10. Interdependence of rate and enandoselectivity for the hydrogenation of ethyl pyruvate with Pt/Al203 catalysts, a) For varying HCd concentrations (results from Fig. 9) — ee versus 1/rate and —ee versus rate b) For different Pt/AljOj catalysts modified with cinchonidine [59]. Fig. 10. Interdependence of rate and enandoselectivity for the hydrogenation of ethyl pyruvate with Pt/Al203 catalysts, a) For varying HCd concentrations (results from Fig. 9) — ee versus 1/rate and —ee versus rate b) For different Pt/AljOj catalysts modified with cinchonidine [59].
Figure 1. The effects of a series of Mo/AljOj catalysts with varying Mo loading (0-10%(m/m)) on the coke selectivity and the hydrodesulfurization activity. The HDS activity has been expressed as a second-order rate constant ( hds)< Process conditions temperature 450 C, pressure 30 bar, H2/oil ratio 900 Nl/kg, WHSV 1.3 kg/(kg h) and run length 180 h. Figure 1. The effects of a series of Mo/AljOj catalysts with varying Mo loading (0-10%(m/m)) on the coke selectivity and the hydrodesulfurization activity. The HDS activity has been expressed as a second-order rate constant ( hds)< Process conditions temperature 450 C, pressure 30 bar, H2/oil ratio 900 Nl/kg, WHSV 1.3 kg/(kg h) and run length 180 h.
Figure 4. The XRD pattern of a spent NiO/AljOj catalyst showing absence of any a-Al205. Figure 4. The XRD pattern of a spent NiO/AljOj catalyst showing absence of any a-Al205.
Figure 23. Typical modification of reactor temperature versus time in the activation of a CoMo/y-AljOj catalyst with a spiked feed. Figure 23. Typical modification of reactor temperature versus time in the activation of a CoMo/y-AljOj catalyst with a spiked feed.
Finally a study on the efTect of temperature on the OSC was performed on Pt/AljOj, Rh/AljOj, Pt/Ce02-Al203 and Rh/CeOj-AljOj catalysts [32 33]. For Pt/Al20a almost no influence of the temperature could be detected (Fig. 7.4). [Pg.255]

A novel dehydrogenation-reduction of nitrocyclohexane at 420°C over PdO-AljOj catalysts yields aniline ... [Pg.31]

A theoretical understanding of the diffusion of hydrocarbons through the porous catalyst layer (see Fig. 2.45) may be obtained by simulations using semi-classical molecular dynamics (as in Fig. 2.3). Such calculations have been performed for the penetration of various hydrocarbons through AljOj catalysts with and without Pt insertions (Szczygiel and Szyja, 2004). As indicated in Fig. 2.46, it is found that fuel transport depends on both cavity structure and the adsorption on internal catalyst walls. [Pg.75]

P5C-5 The kinetics of vapor-phase ammoxidation of 3-methylpyridine over a promoted VjOj —AljOj catalyst was reported in Chem. Eng. Set, 35, 1425 (1980). Suggest a mechanism and rate-limiting step consistent with each of the two mechanisms proposed. In each case how would you plot the data to extract the rate law parameters Which mechanism is supported by the data ... [Pg.435]

Ni/MgO did not so high activity, but rather stable. 3 mol% Ni/AljOj catalyst deactivated very rapidly and finally the reactor was plugged with the deposited carbon. We measured the amount of total carbon species on the catalyst surface after the reaction for 120 h. The results were 0.1 wt% on Ni o,o3Mgo.970,1.6 wt% Ni/MgO and 10 wt% on Ni/AljOj catalysts. From these results, it was found that Ni Mg j O catalyst has high resistance to carbon deposition in CO 2 reforming of methane. [Pg.376]

Changes in the surface area and Cu surface area of Cu/ZnO/ZrOj/AljOj catalysts without and with silica during methanol synthesis from CO2 and H2... [Pg.551]

Nichio N, Casella ML, Santori GF, Ponzi EN, Ferretti OA (2000) Stability promotion of Ni/ alpha-AljOj catalysts by tin added via surface organometallic chemistry on metals - application in methane reforming processes. Catal Today 62 231... [Pg.291]

Fottinger K, Schlogl R, Rupprechter G (2008). The mechanism of carbonate formation on Pd-AljOj catalysts. Chem Commim, 3, 320... [Pg.391]

Carbon formation may lead to blockage of the reactor tubes resulting in the development of hot spots or it may cause catalyst breakdown [7]. It is therefore important to avoid carbon formation by choosing suitable operating conditions. Carbon formation may also be reduced by proper formulation of the catalyst itself. The present work focuses on carbon formation from CH4 and CH4 mixed with HjO or Hj on a Ni/a-AljOj catalyst and on the same catalyst promoted by Ca and Mg. [Pg.562]

Fig. 3. The effect on catalyst coking at 973 K of adding Mg and Ca to the Ni/a-AljOj catalyst. Fig. 3. The effect on catalyst coking at 973 K of adding Mg and Ca to the Ni/a-AljOj catalyst.
Carbon accumulation on unpromoted Ni, thought to be highly filamenteous, typically follows an autoaccelerating trend. Adding Mg and Ca as promoters to the Ni/a-AljOj catalyst, increases carbon formation rates. [Pg.566]

The kinetic parameters (apparent activation energies, orders versus hydrogen and hydrocarbon) have been determined for all the isomerization and hydrocracking reactions of n-pentane and 2-methylbutane on a Pt/AljOj catalyst of low dispersion (10% Pt d = 90 A) 40). n-Pentane-2- C and 2-methylbutane-2- C were used to estimate the contributions of cyclic type and bond shift isomerization, respectively. As shown in Table II, the reactions... [Pg.22]

Further evidence for the existence of two bond shift mechanisms and also for the metallocyclobutane mechanism are provided by the isomerization of C labeled C7 hydrocarbons 2,3-dimethylpentane (3S), 2-methyl-hexane (45), and 3-methylhexane (47) on Pt/AljOj catalysts. [Pg.24]

A more careful study of the hydrogenolysis of methylcyclopentane on two catalysts of extreme dispersion (0.2 and 10% Pt) showed that, in the temperature range 250°-310°C, the product distributions were temperature insensitive on the 0.2% Pt/Al2O3 catalyst, but temperature sensitive on the 10% Pt/AljOj catalyst (86). On the latter, all the observed distributions appeared as combinations of two limiting distributions, one of which includes only methylpentanes and therefore corresponds to a completely selective hydrogenolysis of—CH2—CH2— bonds the other one contains n-hexane, but is different from the one obtained on the 0.2% Pt/Al2O3 catalyst. Platinum films are intermediate between the two types of supported catalysts (86,87. ... [Pg.29]

On Pt/AljOj catalysts, 1,2-dimethylcyclopentane produces both toluene and n-heptane. The amounts of both products increase with decreasing hydrogen pressure 94) (see Section IV, Table VI). However, under the same conditions, toluene is not formed from 1,3-dimethylcyclopentane or from ethylcyclopentane. This suggests that metallocyclobutanes are more easily formed (or cleaved in the appropriate fashion) when a tertiary carbon atom is involved in the bonding with the metal. [Pg.54]


See other pages where AljOj catalysts is mentioned: [Pg.701]    [Pg.709]    [Pg.157]    [Pg.191]    [Pg.316]    [Pg.40]    [Pg.161]    [Pg.465]    [Pg.276]    [Pg.391]    [Pg.356]    [Pg.195]    [Pg.476]    [Pg.537]    [Pg.561]    [Pg.563]    [Pg.564]    [Pg.625]   
See also in sourсe #XX -- [ Pg.195 ]




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