Homogeneous Oxidation

Gas-Phase Oxidations, Homogeneous and Heterogeneous Catalysis, Applied Oxidations and Synthetic Processes... 

Heterogeneous catalysts are mostly metals or metal oxides. They can be used as they are or together with inert carriers, which themselves are usually metal oxides. Homogeneous catalysts are as a rule cations of certain metals or complexes of metal atoms with an organic molecule (ligands). 

Sheldon RA, Brink GJ ten, Arends IWCE (2002) Selective oxidation - homogeneous. Encyclopedia of catalysis. Wiley, http //www.mrw.interscience.wiley.com... 

Nitramine (RDX or HMX) oxidizer Homogeneous colloidal propellant consisting of nitrocellulose dissolved in plasticizer comprised of nitroglycerine and inert materials Composite or double-base propellant in which polymer is dissolved in plasticizier... 

Hoffmann T., O Dowd C., and Seinfeld J. H. (2001) Iodine oxide homogeneous nucleation an explanation for coastal new particle production. Geophys. Res. Lett. 28,1949-1952. 

At temperatures above 595 K ammonia is oxidized homogeneously or according to... 

Hoffman, T., C.D. O Dowd, and J.H. Seinfeld, Iodine oxide homogeneous nucleation An explanation for coastal new particle formation. Geophys Res Lett 28, 1949, 2001. 

In a similar reaction, (,S )-1 was transformed to 5, an intermediate in the synthesis of optically active polyzonimine (a millipede pheromone) via 3 and 4 after sodium borohydride reduction, acetylation and permanganate oxidation. Homogeneous (i J-aldehyde 4 is isolated after purification by GC. Based on the transition state models the absolute configuration of 4 was predicted to have R configuration346. 

Wong WK, Chen XP, Pan WX, Guo JP, Wong WY (2002) Eur J Inorg Chem 231 Sheldon RA, Brink GJ ten, Arends IWCE (2002) Selective oxidation - homogeneous. Encyclopedia of catalysis. Wiley, http //wwwjnrw.interscience.wiley.com Baric G, Dakka J, Sasson Y (1988) J Org Chem 53 3553... 

Ammonium quaternary salts Ethylbenzene oxidation process Gas-phase oxidation Homogeneous catalytic oxidations Liquid-phase hydrocarbon oxidation Monodentate axial ligands p-xylene... 

A typical procedure involves adding a suitable amount of urea to an acidified solution of, e.g., aluminum ions. A weak acid, such as formic or acetic acid, is also added to provide buffering action so that the pH does not rise too rapidly as the urea hydrolyzes. The solution is then heated until the pH rises to the desired value, which is 4 for quantitative precipitation of hydrated aluminum oxide. Homogenously precipitated hydrated aluminum oxide is superior to that precipitated by addition of ammonia in that it is purei denser, more compact, and more easily filtered. Some reagents used in PFHS are listed in Table 2. 

To explain the various effects of temperature, time of re-oxidation, air flow and substrate thickness additional microscopic and SEM investigations have been carried out on re-oxidized samples. Microscopic pictures of areas of fracture of such cells revealed that a big gradient in the local degree of oxidation appears at higher temperatures (T > 700 C). At lower temperatures no such gradient can be observed, the substrate is re-oxidized homogenous (see Fig. 9). Half of the substrate of the sample re-oxidlzed at 800°C is completely re-oxidized (local DoO 100%), the other half is still completely reduced (local DoO 0%). A le-oxidation front appears in the substrate that separates the reoxidized part from the reduced part. The sample in Fig. 9 (b) re-oxidised at 600°C has a local DoO of about 50% everywhere in the substrate, no re-o. idation front can be observed, no gradient >pears in the local DoO. 

Key words Catalytic oxidation, homogeneous catalysis, dioxygen activation, dioxygen conplexes, biomimetic oxidation, functional metaUoenzyme models, oxidation mechanisms, oxidative dehydrogenation, oxygen insertion, aUcene epoxidation, catecholase reaction... 

DEHYDRATION OF METHANE GAS BY MODIFIED POLYPHENYLENE OXIDE HOMOGENEOUS MEMBRANES... 

---