Mesocellular foams

Cross-linked CPO aggregates in the pores of mesocellular foams The CPO-CLEAs (cross-linked enzyme aggregates) supported in mesocellular foams were more stable against leaching than conventional catalysts prepared by physical adsorption of CPO on the same support [10]... 

Immobilized CPO in the mesoporous silicate material, mesocellular foam The optimal pH at which the maximum amount of enzyme is immobilized was determined to be pH 3.4, slightly below the isoelectric point of the enzyme [12]... 

Jung D, Paradiso M, Wallacher D et al (2009) Formation of cross-linked chloroperoxidase aggregates in the pores of mesocellular foams characterization by SANS and catalytic properties. ChemSusChem 2 161-164... 

Note that depending on the species and their location in the micelles, cosurfactant agents can also induce swelling effects. Moreover, depending on the concentration of the organic additives, other effects may be generated, in particular emulsion and phase separation, which may be exploited to produce specific mesostructures (mesocellular foams) and particle morphologies (colloidal spheres and hollow stmctures). 

Lukens et al. [88] studied N2 adsorption on a large series of MCM-41, SBA-15 and spherical pore mesocellular foams. They proposed the use of a simplified method with respect to Sing s one. The quantity is defined by ... 

Making use of constrained polymerisation of divinylbenzene on surfactant-modified colloid silica, Jang and Lim prepared carbon nanocapsules and mesocellular foams. Later, they reported that mesoporous carbons with highly uniform and tunable mesopores were fabricated by one-step vapour deposition polymerisation using colloidal silica nanoparticles as template and polyacrylonitrile as carbon precursor. Hampsey et al. recently reported the synthesis of spherical mesoporous carbons via an aerosol-based, one-step approach using colloidal silica particles and/or silicate clusters as template. ... 

Lettow, J.S. Han. Y.J. Schmidt-Winkel, P. Yang, P. Zhao, D. Stucky. G.D. Ying, J.Y. Hexagonal to mesocellular foam phase transition in polymer-templated mesoporous silicas. Langmuir 2000. 16. 8291. 

Maruoka, et al. reported unprecedented high exo-selectivity in the asymmetric Diels-Alder reaction of a, 3-unsaturated aldehydes by a protonic acid-(i )-binaphthyl-based diamine salt catalyst 48, Scheme 3.15 [27], On the other hand, the Diels-Alder reaction of cyclopentadiene and cinnamaldehyde via enantioselective catalysis over mesocellular foams was reported by Ying and his co-workers [28]. 

More recently, BackvalFs group reported the DKR of the jS-amino ester, ethyl 3-amino-3-phenylpropanoate, using Candida antarctica lipase A (CAL-A) immobilised in mesocellular foam (GamP-MCF) in combination with the methoxy analogue of Shvo s catalyst at 90°C. It was shown that the use of 2,4-dimethyl-3-pentanol as a hydrogen donor allowed side product formation to be suppressed. Thus, the reaction performed in the presence of trifluoroethyl butyrate as the acyl donor provided the corresponding (5)-amide in 85% yield and 89% ee. 

Further examples of supported catalysts used for ATH of imines include those based on recyclable silica [84], functionalized MCM-41 [85], siliceous mesocellular foam [86] and magnetic mesoporous silica. In the latter case, the reusable immobilized catalyst exhibited high activity and enantioselectivities in the ATH of imines in FA/TEA. It was able to be separated mechanically using an external magnet to facilitate ready recycling [87],... 

A Cu-Box complex supported on monolith (51) was developed for the enantio-selective cydopropanation of ethyl diazoacetate. The flow reactions using (51) provided an increase in enantioselectivities of about 20% relative to those for the homogenous batch process (Scheme 7.38) [142]. Pyridine-oxazolidine based monoliths (52) and (53), whose central metals were Ru and Cu, respectively, were also developed [143,144]. Mesoporous silica was utilized as a support for the Cu-Box complex for asymmetric cydopropanation in a flow reador. Aza(bisoxazoline) was easily immobilized on siliceous mesocellular foam MCF) microparticles, which are... 

Singapore, constructed (Chem. Commun. 2008, 4312) the metathesis catalyst 22, covalently bound to siliceous mesocellular foam. At 5% catalyst loading, the tenth cycle for the cyclization of 23 to 24 gave the same yield as the first cycle, 97%. Ru residues in solution... 

More recently, Backvall and coworkers have described a very effective catalyst for the racemization of amines highly dispersed Pd nanoparticles supported in the large pores of silica-based mesocellular foam (MCF) [104]. This catalyst proved to be a more robust catalyst in amine racemization than any other catalysts reported before and is completely compatible with CALB activity. 

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