Zeolites oxidative

Oxides are widely used as supports. The major examples are silica (porous Si02), alumina (porous AI2O3), and zeolites. Oxides are also u.sed as catalysts. In bulk chemistry they are... 

Tanabe and Hdlderich (1999) have given an extensive statistical survey of industrial processes using solid acids/bases as catalysts. Over 300 solids and bases have been covered. A variety of reactions like alkylation, isomerization, amination, cracking, and etherification with catalysts like zeolites, oxides, complex oxides, phosphates and ion-exchange resins have been covered. Over 120 industrial processes are referred with 180 different catalysts. 

Burch, R., Breen, J.P. and Meunier, F.C. (2002) A review of the selective reduction of NO, with hydrocarbons under lean-burn conditions with non-zeolitic oxides and platinum group metal catalysts, Appl. Catal. B, 39, 283. 

In comparable reaction conditions as Pd +Cu +Y, Pd + and Cu2+ exchanged pentasil and ferrierite zeolites show a different type of activity [31]. The main products formed by propylene oxidation on these catalysts are acrolein and propionaldehyde below 120°C and 2-propanol above 120 C. Above 150°C consecutive oxidation of 2-propano1 to acetone is observed. The catalytic role of Pd and Cu in the 2-propanol synthesis is proposed to follow the Wacker concept. It is striking that when Pd + and Cu2+ are exchanged in 10-membered ring zeolites, oxidation of a primary carbon atoms seems possible, as acrolein and propionaldehyde are obtained from propylene. 

It is easy to distinguish Ba + ions from Na+ for several reasons. Firstly, their atomic scattering factors are quite different, 54 e for Ba2+ vs 10 e for Na+. Secondly, their ionic radii are quite different, Ba2+ = 1.34 X and Na = 0.97 X (5). Also, the approach distances between these ions and zeolite oxide ions in dehydrated Na 2 A (16) and hydrated Bag-A are known (see Table III). Finally, the requirement that 12 cationic charges be placed per unit cell does not allow the major positions to refine to acceptable occupancies with an alternative assignment of ionic identities. 

Non-zeolitic Oxide Catalysts Boria- and Phosphate-based Catalysts... 

Benzoylation. The rcg with a,a,a-trichlorotoluene i lyzed by HZSM-5 zeolite. Oxidative dimerization ... 

The influence of the preparation method of In-modified zeolite catalysts for the SCR of NOx by methane on the structure of In species formed and the catalytic activity has been studied. The structure of the catalysts has been investigated by XPS, ISS, XAFS, FTIR, electron microscopy and TPR. Dependent on the preparation, indium may occupy zeolite cation sites or form intra- and extra-zeolite oxide aggregates. It was found that indium ions at cation sites provide a low-temperature SCR activity while clustered species are active at high temperatures. 

Co-zeolites, oxidation catalysts 27-P-08 Composite, ZSM-5/Raney metal 30-P-29... 

Pd°][Cu°]-zeolites oxidation of ethylene to acetaldehyde in the Wacker process... 

This chapter has presented a brief overview of various studies in which calorimetry has been used to characterize zeolites, oxides, and metallic catalysts. It is apparent from the results in the literature that microcalorimetry is a very powerful technique even if it does not provide direct information about the molecular nature of the adsorbed species. 

In zeolite catalysis, emphasis has been placed on the reactions catalyzed by acids. However, complete ion exchange with alkali metal cations such as Rb". and Cs" would allow for the preparationof weakly basic zeolites. Oxide ligands as counteranions of these alkali metal cations act as basic sites. Their basicity depends on the... 

Incorporated elements should not significantly alter the chemical shift as with respect to silicalite as the colliding walls, are essentially zeolitic oxide ions. 

Not given/ zeolites. oxidation of corresp. amine with H2O2. elusion compound, nes in mineral oil. perfine tensors in polycrystalline and glass (a) EPR, ELDOR (b) EN-DOR/ y matrices. (a) 84Hydl ) (b) 85Brul O)... 

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