Alkanes nonreactivity

Hydrogenation of Acetylenes. Complete hydrogenation of acetylenes to the corresponding alkanes, which maybe requited to remove acetylenic species from a mixture, or as a part of a multistep synthesis, may be accompHshed using <5 wt % palladium or platinum on alumina in a nonreactive solvent under very mild conditions, ie, <100°C, <1 MPa (10 atm). Platinum is preferred in those cases where it is desired to avoid isomeri2ation of the intermediate olefin. Silver on alumina also can be used in this appHcation as can unsupported platinum metal. 

In an alkane, all the carbon atoms have hydrogen attached to them, i.e., for a particular arrangement of carbon atoms the alkane is the fully reduced form. Reactions of alkanes that do not involve cleavage of the carbon chain, are, therefore, necessarily oxidations. An important exception, which is particularly relevant here, is hydrogen-deuterium exchange. In one sense this is a nonreaction in that the alkane is both the reactant and the product. 

NR = nonreactive toward hydrocarbons PO = oxidation of phosphines to phosphine oxides MF — peroxometallacyclic adduct formation with cyanoalkenes NSE — nonstereoselective epoxidation SE=stereoselective epoxidation AE = asymmetric epoxidation HA- hydroxylation of alkanes HB=hydroxylation of arenes OA = oxidation of alcohols to carbonyl compounds K = ketonization of Lermina 1 alkenes SO oxidation of S02 to coordinated S04 MO = metallaozonide formation with carbonyl compounds I = oxidation of isocyanides to isocyanates. 

As with all substances, polymers have properties that result directly from their molecular structure. For example, polyethylene is a long-chain alkane. Thus, it has a waxy feel, does not dissolve in water, is nonreactive, and is a poor electrical conductor. These properties make it ideal for use in food and beverage containers and as an insulator on electrical wire and TV cable. 

In the case of heavier alkanes, along with a similar branching mechanism, there are additional possibilities, such as the rapid decomposition of the peroxy radical to the respective olefin and the hydroperoxy radical HO, virtually nonreactive under these conditions ... 

---