Organic bases attached to mesoporous silicas

Stronger solid base catalysts can be prepared by grafting guanidine bases to mesoporous silicas. For example, the functionalization of MCM-41 with 1,5,7-triazabicyclo[4,4,0]dec-5-ene (TBD), as shown in Fig. 2.40, afforded a material (MCM-TBD) that was an effective catalyst for Michael additions with ethylcya-noacetate or diethylmalonate (Fig. 2.41) [136]. 

In a variation on this theme, a bulky guanidine derivative, N,N,N -tricyclohex-ylguanidine was encapsulated by assembly within the supercages of hydrophobic zeolite Y. The resulting ship-in-a-bottle catalyst was active in the aldol reaction of 

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Organic bases attached to mesoporous silica surface Primary, secondary and tertiary amines,1169-1711 diamines,[172] ammonium hydroxide11731 and guanidines have been grafted onto MTS surfaces through direct... 

Organic Bases Attached to Mesoporous Silicas as Solid Catalysts... 

Macquarrie, DJ Brunei, D. Solid Base Catalysis. 7.3. Organic bases attached to mesoporous silicas as solid catalysts. In Sheldon, RG van Bekkum. H editors. Fine Chemicals through Heterogeneous Catalysis, Weinheim (Germany), Wiley-VCII, 2001 338-349. 

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