By Ertl G., Knozinger H., Weitkamp J. (ed.)

Show description

Read Online or Download Handbook of Heterogeneous Catalysis PDF

Similar chemistry books

New PDF release: Advances in Nitrogen Heterocycles, Volume 3

This quantity includes a variety of subject matters akin to the activation and manipulation of pyrroles, the synthesis of annelated pyrroles utilizing acylation reactions and the synthesis of kainoids, a kinfolk of hugely biologically lively nitrogen heterocycles.

New PDF release: Applied Polymer Science<span class="edition", Second

Content material: A century of polymer technological know-how and know-how / Herman F. Mark -- creation to polymer technological know-how and expertise / Charles E. Carraher, Jr. and Raymond B. Seymour -- Anionic polymerization / Maurice Morton -- Coordinated anionic polymerization and polymerization mechanisms / Frederick J. Karol -- contemporary advancements in cationic polymerization / Virgil Percec -- Emulsion polymerization / Gary W.

Extra info for Handbook of Heterogeneous Catalysis

Example text

12]. Copper, having the highest melting point, is melted and then aluminum is added. ± Zn(OH2) + 2NaOH (7) It is the reprecipitation of Zn(OH)2 in the porous skeletal copper which provides promotion in methanol synthesis, water gas shift, and other reactions. The highly dispersed reprecipitated Zn(OH)2 decomposes at around 400 K to form ZnO which is an active promoter of copper catalysts. When leaching aluminum alloys it is generally desirable to use high concentrations of sodium hydroxide in order to remove the Al as NaAlO2 and avoid reprecipitation of Al as bayerite (Al2Oj 3H2O).

He prepared his catalysts from Devarda' s alloy which contained 45wt% Cu, 50wt% Al, and 5wt% Zn. Marsden and co-workers [12] were the first to use skeletal catalysts prepared from CuZn-Al alloys for methanol synthesis. Alloys containing 50wt% Al and 0-50 wt% Cu with the balance Zn were employed. Optimum activity for low temperature methanol synthesis was found for catalysts prepared by leaching alloys containing 50wt% Al, 33-43 wt% Cu and 7-17 wt% Zn. Fricdrich et al. [26] showed that catalysts prepared from alloys containing approximately 50wt% Al, 30-36 wt% Cu and 14-20wt% Zn had greatest activity for methanol synthesis.

Often the composition of the precipitate will reflect the solution concentrations, as was shown for CuO/ZnO catalysts for methanol synthesis [18], but this is not necessarily the case. For alminum phosphates it was found that at low P:A1 ratios the precipitate composition is identical to the solution composition, but if the P:A1 ratio in the solution comes close to and exceeds unity, the precipitate composition asymptotically approaches a P:A1 ratio of 1 [19]. Deviations from solution composition in coprecipitation processes will generally occur if solubilities of the different compounds differ strongly and precipitation is not complete or, if in addition to stoichiometric compounds, only one component forms an insoluble precipitate; this the case for the aluminum phosphate.

Download PDF sample

Handbook of Heterogeneous Catalysis by Ertl G., Knozinger H., Weitkamp J. (ed.)

by Charles

Rated 4.43 of 5 – based on 29 votes