Inorganic surface grafting

The fundamental task, in our opinion, is to correlate the principles and methods of the proposed synthesis with those of mechanochemical synthesis. Thus, besides the destruction processes and mechanochemical synthesis discussed in the literature, other lands of transformations sometimes occur as side reactions, or even as major processes. These include chemical fixation of small molecules (methyl chloride or butyl alcohol) on mechanically activated macromolecular backbones grafting of inorganic surfaces (quartz, metals, metallic oxides, inorganic salts, etc.) dispersed by vibratory milling on polymerized fragments synthesized from monomers present in the reaction medium, and activated by centers on the inorganic surface (14) and the possibility of some reactions (such as nitration), achieved so far on macromolecular supports and only as side reactions. 

Elimination of alkyl or 7t-allyl ligands as hydrocarbons on reaction with acidic OH (or SH) groups may graft metal ensembles to inorganic surfaces such as oxides. Some of these reactions occur via initial oxidative addition of OH (or SH) to the metal followed by reductive elimination of the hydrocarbon, leaving the metal-support M—O bonds ... 

Non-cross-linked polymers can be used in this way just as cross-linked polymers can. For example, we have used polyethylene supports with surface grafts to support Pd(0) catalysts [133,134]. In these cases, the polymer-immobilized catalyst is used in exactly the same way as an insoluble polymer-bound catalyst. Such supported catalysts do require that the insoluble polymer be swollen or permeable to substrates or that the catalysts be within a solvent-permeable, thin immobilized graft. While this approach can be useful, it takes no advantage of the polymer s solubility. It is an approach that conceptually is no different than that used with insoluble inorganic supports or with polymers that are by design insoluble by virtue of cross-linking, and is an approach to catalyst immobilization that is not further discussed since this review is focused on polymer-immobilized catalysts that are used under solution-state conditions. 

Free-radical method usually requires a surface activation by a direct attachment of initiator molecules or by the introduction of surface active sites (i.e., vinyl groups in surface graft polymerization of vinyl monomers). In particular, organosilane coupling agents (i.e., chloro- and alkoxysilanes) are commonly employed to introduce active sites onto inorganic oxide surfaces. 

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