Oxidation with Other Metal Derivatives

The oxidation of alcohols is not limited to chromium derivatives, DMSO derivatives, or hypervalent iodine compounds. There are several metal-based reagents that can be very effective, particularly with sensitive functionality. This section will examine several of the more important regents. 

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Chemical Properties. Higher a-olefins are exceedingly reactive because their double bond provides the reactive site for catalytic activation as well as numerous radical and ionic reactions. These olefins also participate in additional reactions, such as oxidations, hydrogenation, double-bond isomerization, complex formation with transition-metal derivatives, polymerization, and copolymerization with other olefins in the presence of Ziegler-Natta, metallocene, and cationic catalysts. All olefins readily form peroxides by exposure to air. 

Most of the chemistry performed on orthometallated ylides has been carried out with Pd and Pt as metal centers. Few examples dealing with other metals (Co, Ru, and Os mainly, see 62 and 63) have been reported. Complex (74) has been prepared by reaction of a Ru-vinylidene with PPh3 [153] while Os derivative (75) has been obtained after treatment of the methylimido complex with PPh3 [154]. Orthoruthe-nated indenyl complexes [155] have been synthesized by reaction of the halomethyl precursors with PPh3, and the oxidative addition of the yUde Ph3P=CHC(0)H to clusters of Ru and/or Os also allows the synthesis of orthometallated complexes... 

The first isolated and characterised species that could be envisioned as intermediates in the initiation step for the coordination polymerisation of epoxides when using metal carboxylate catalysts were complexes formed between cadmium carboxylates, solubilised in organic solvents by the tris-3-phenylpyrazole hydroborate ligand, and epoxides such as propylene oxide and cyclohexene oxide [68]. Other epoxide complexes with various metal derivatives have also been reported in the literature [69-72],... 

The monomer ethylbenzene is made from petroleum-derived benzene and ethylene. Free radical polymerization is usually carried out in the gas phase with an iron oxide or other metal oxide catalyst yielding PS resin ... 

When the operating temperature exceeds ca 93°C, the catalytic effects of metals become an important factor in promoting oil oxidation. Inhibitors that reduce this catalytic effect usually react with the surfaces of the metals to form protective coatings (see Metal surface treatments). Typical metal deactivators are the zinc dithiophosphates which also decompose hydroperoxides at temperatures above 93°C. Other metal deactivators include triazole and thiodiazole derivatives. Some copper salts intentionally put into lubricants counteract or reduce the catalytic effect of metals. 

Phosphorus compounds exhibit an enormous variety of chemical and physical properties as a result of the wide range ia the oxidation states and coordination numbers for the phosphoms atom. The most commonly encountered phosphoms compounds are the oxide, haUde, sulfide, hydride, nitrogen, metal, and organic derivatives, all of which are of iadustrial importance. The hahde, hydride, and metal derivatives, and to a lesser extent the oxides and sulfides, are reactive iatermediates for forming phosphoms bonds with other elements. Phosphoms-containing compounds represented about 6—7% of the compound hstiugs ia Chemical Abstracts as of 1993 (1). 

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