PhantomWolf
Penultimate Amazing
- Joined
- Mar 6, 2007
- Messages
- 21,203
http://www.rsc.org/delivery/_ArticleLinking/DisplayArticleForFree.cfm?doi=b310405b&JournalCode=CC
http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/2005/127/i17/abs/ja050389w.html
"Mesoporous silicas such as SBA-15 and MCM-41 are being actively investigated for potential applications in catalysis, separations, and synthesis of nanostructured materials. A new method for functionalizing these mesoporous silicas with aromatic phenols is described. The resulting novel hybrid materials possess silyl aryl ether linkages to the silica surface that are thermally stable to ca. 550 °C, but can be easily cleaved at room temperature with aqueous base for quantitative recovery of the organic moieties. The materials have been characterized by nitrogen physisorption, FTIR, NMR, and quantitative analysis of surface coverages. The maximum densities of 1,3-diphenylpropane (DPP) molecules that could be grafted to the surface were less than those measured on a nonporous, fumed silica (Cabosil) and were also found to decrease as a function of decreasing pore size (5.6−1.7 nm). This is a consequence of steric congestion in the pores that is magnified at the smaller pore sizes, consistent with parallel studies conducted using a conventional silylating reagent, 1,1,3,3-tetramethyldisilazane. Pyrolysis of the silica-immobilized DPP revealed that pore confinement leads to enhanced rates and altered product selectivity for this free-radical reaction compared with the nonporous silica, and the rates and selectivities also depended on pore size. The influence of confinement is discussed in terms of enhanced encounter frequencies for bimolecular reaction steps and pore surface curvature that alters the accessibility and resultant selectivity for hydrogen transfer steps. "
https://e-reports-ext.llnl.gov/pdf/247064.pdf
Still going around in circles and clutching at straws GiE? You really should read your links, you might have discovered that what you link to isn't the production of a Sol-Gel using DDP, but rather using a Sol-Gel to act as a catalyst to aid in the pyrolysis of DDP. Perhaps you need to try again. I will give you a brownie point for finally getting the chemical right though.