Sililation

FIGURE 16.17 Mass spectra of the sililated 3-0-acetyl-ll-OH- 3-boswellic acid (compound 12) and 3-0-acetyl-9,ll-dehydro-P-boswellic acid (compound 13). 

The frequency of PDMS chain mobility in the interfacial layer is largely dependent on the type of silica surface. Water adsorption by the hydrophilic silicas causes the degree of chain immobilisation in the interface to decrease [107]. Sililation of the silica surface results in a significant decrease in the strength of adsorption interactions at the silica... 

Park D-H, Nishiyama N, Egashira Y, and Ueyama K. Separation of organic/water mixtures with sililated MCM-48 silica membranes. 

Posttreatment processes have been used to improve the quahty of the resulting membranes, such as ion exchange (to provide catalytic properties or change them between hydrophobic and hydrophilic surfaces), liquid or vapor sililation, coke deposition, CVD (chemical vapor deposition), and ALCVD (atomic layer chemical vapor deposition). These techniques are used to reduce the intercrystalline gaps and the pore-mouth size, modify the acid properties of the modified membranes, and remove amorphous material. Some of these modifications have demonstrated very high separation selectivities for the resulting membranes however, in many cases, they are of limited practical application due to the relatively low fluxes obtained. 

I ll 3si a lisis iisls 2=i s 5S si aisia Hiss asEiS silil ilsil iasll lisil ssill... 

Ills i 2iiH IliH iiiss siili lissi sslll llsls iigsi isill ilsii ISils Silil... 

I tf i spis PPs slip ipii PPI Pill islll silil 3 S55 5S5 S 82 SS23... 

Hi silil i H ill i i ill sisii Hiss IHH Hiis sslsi liHsi... 

E. Ya. Lukevits and A. E. Zablotskaya, Silil nyi Metod Sinteza Nukleozidov. Zinatne, Riga, 1985. 

Nitrile reduction with BH3 proceeded with cycUzation to give 8. This underwent catalytic hydrogenation in the presence of formic acid to afford the (-)-deacetylanisomycin (2). Compound 2 was subjected to a five-step sequence to produce 1 [2,26,50-52]. Thus, N-carbamate protection of 2 afforded carbamate 9, which was selectively sililated to give 10. This was acetylated to produce 11 that on treatment with TBAF followed by catalytic hydrogenation furnished (-)-anisomycin (1). 

Lozano et al. reported on an improved method for forming high molecular weight polyimides [88]. They used in situ sililation of the diamines to cany out the reactiOTi. Trimethylchlorosilane is added to the diamine solution prior to the addition of the electrophilic monomer. 

Neiitniliziition with po.s.silile prccipiration of. sulfides (FeSO, ). 

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