Functionalized mesoporous ordered materials

Sites with intermediate basicity (secondary amines) are more active than those wherein CO is held either too weakly (tertiary N atoms) or too strongly (primary N atoms). Furthermore, the incorporation of Lewis acidic Ti and AP ions to SBA-15 enhances the adsorption of epoxide and hence improves the catalytic activity. 

Zhou et al. [95] investigated by in situ DRIFTS the CO activation and further coupling reaction with epoxides using novel heterogeneous catalyst containing N-heterocyclic carbene (NHC) anchored in MCM-41. 

Tasci et al. [114] investigated Zn(II) and Cu(II)-salen supported on SiO as catalysts for the synthesis of PC at 100°C, 10 bar after 1 h of reaction without an addition of any solvent but in the presence of Lewis base e.g. DMAP. Cu complexes were shghtly more efficient than Zn complexes when they were tested with the same ligand. An outstanding Yp, of 93%, respectively, was reported at 120°C using the Cu-salen-SiO catalyst. 

Metal-salen complexes immobilized on amorphous or mesostructured SiO were also investigated as acid-base catalysts for the cycHc carbonates synthesis imder continuous operation in gas phase. Despite the high selectivity to the cyclic carbonates the major drawback of these organic-inorganic hybrid catalysts were the catalyst deactivation, likely due to the cleavage of bonds which link the salen ligand and SiO imder the reaction conditions [78,82,106-108,111-113]. 

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The mesoporous ordered silicas of different type represent the new generation of materials with unique properties. The discovery of these materials became basis for creation of new catalysts, adsorbents, sensors and supporter for other molecules. The most important way of the modifying physical and chemical properties of mesopurous silicas consist in organic components incorporation on the silica surface as part of the silicate walls or their insertion within channels of the mesopores. This ensured that interest in synthesis and study of functionalized mesoporous materials shai ply grew. In spite of it, these materials are studied insufficiently. 

Sulfonic Acid Functionalization of Ordered Mesoporous Materials and Periodic Organosilicas... 

Since the discovery of ordered mesoporous silica materials such as MCM-41 [1] and FSM-16 [2], many attempts have been made to apply them for various type of catalysis [3]. Especially, much attention has been paid to the catalytic functions generated through the incorporation of heteroelements into mesoporous silica matrix, but not so much to those of mesoporous silica without heteroelements. This may be because silica itself is known to be inactive for many catalytic reactions. 

SBA-15 is a mesoporous ordered silica with promising properties as a catalyst support [1], where functionalization of the siliceous carrier with an active component can be achieved through a number of methods [2]. In this study we describe the use of the deposition-precipitation technique (DP) employed to functionalize the SBA-15 with Pt. The use of the DP method on the SBA class of materials has not been studied so far, excluding a few studies dealing with deposition of gold on titania-modified SBA-15 [3, 4]. The method... 

The incorporation of functional molecules in these systems is a new development of advanced materials research and various examples of inclusion chemistry in ordered mesoporous host materials are known [2]. 

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