Synthesis graft

The Ti was loaded using two methods direct incorporation into the synthesis mixture, and post-synthesis grafting. In all cases the Ti-loading was 1.5 -1.8 wt%. Selectivity towards the epoxide was always 100%. Table 41.1 summarizes the results comparing Ti-TUD-1 and Ti-MCM-41 for cyclohexene epoxidation (15). For the direct incorporation, Ti-TUD-1 is five times more active than Ti-MCM-41, even though they have equivalent surface area. However, the grafted MCM-41 is also more active than its as-synthesized counterpart. 

Synthesis. Graft copolymer was formed in aqueous solution by ceric-ion-initiated, radical polymerization of monomer on starch. Polymerization was conducted in an inert, atmosphere. Details of the synthesis procedure may be found in references 41 to 43 In recovering the polymer product, freeze drying was used with care since freeze drying produces a more dissolvable and useful product but can degrade polymers with molecular weights of 1 million or more. Poly(starch-g-(1-amidoethylene)) Poly(starch-g-(1-amidoethylene))... 

Deleuze et al. used the same approach for the synthesis and functionalization of emulsion-derived polymeric foams [119]. Alternatively, a post-synthesis grafting method recently developed in our group offers access to high-capacity functionalized monolithic systems. Such high capacity monoliths are vital to various applications such as catalysis, extraction of environmental contaminants, extraction of biochemicals for either pharmaceutical or clinical purposes or, more generally, separation techniques [100]. With these systems, amounts of grafted monomers can exceed 1 mmol/g [94]. 

There are two major paths to generate a mesoporous titanosilica framework substitution by one-pot synthesis and post-synthesis grafting. Framework substitution, as used with MCM-41 and MCM-48, can result in low utilization of the available titanium centers. Post-synthesis grafting is more effective at generating a high concentration of accessible Ti centers however, it can be a complicated and, hence, costly synthesis method. 

Modification of mesoporous silica nanoparticles using the bifunctional strategy, post-synthesis grafting, and backfilling strategy in order to make them suitable for drug delivery applications was reported (Lu et al. 2007). The modified nanoparticles were able to deliver the water insoluble drug camptothecin into different types of human cancer cells (Johansson et al. 2008). 

Method of synthesis - grafting mbber which is dispersed with a styrene acrylonitrile (SAN) phase ... 

In case of post synthesis, many research groups have used porous materials (M41S) as support. The pore surface of M41S materials has a number of silanol groups which present as ideal anchor groups. For example, Belkacemi et al. [53] studied mono, di-, and tri-ammonium-functionalized mesoporous SBA-15 silica for the adsorption of monovalent phosphate anions from aqueous solutions via post-synthesis grafting. 

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