Perfluoroalkylsulfonic acids

Similarly, perfluoroalkylsulfonic acid moieties can be covalently attached to a silica matrix by grafting a silica surface with (Et0)3Si(CH2)3(CF2)20(CF2)2S03H (see Fig. 2.27) or by using the latter in a sol-gel synthesis [18, 90]. 

Finally, the functionalization of mesoporous silicas with perfluoroalkylsulfonic acid groups, by grafting with l,2,2-trifluoro-2-hydroxy-l-trifluoromethylethane... 

Fig. 2.30 Mesoporous silica grafted with perfluoroalkylsulfonic acid groups.

Perfluoroalkylsulfonic acids have the general structure F(CF2) S03H, where typically = 4, 6, 8 or 10 (Table 3.1). The most common PFSA is perfluorooctanesulfonic acid (PFOS, = 8). Given the small pAa values of these compounds, approximately—12 [1], PFSAs dissociate completely in the environment ... 

Perfluoroalkylsulfonic acid chains can be anchored to MCM-41 silica. 12 The supported catalyst is prepared by reacting MCM-41 silica with... 

In the first, more carefully studied system H2S04 was used as an initiator. Andrianov s school23) and then Kojima et al.30) reported complicated kinetic data that did not provide sufficient information relative to a coherent polymerization mechanism. In these studies H2SO4., was used because earlier Patrode and Wilcock observed that this acid polymerizes both D3 and D4 to high polymers 15). More recently, as indicated above, stronger perfluoroalkylsulfonic acids have been used and these works provided much more quantiative information. 

Chem. Descrip. Perfluoroalkylsulfonic acid Ionic Nature Anionic... 

Perfluoroalkylsulfonic acid surfactant, enhanced nutritional supplements... 

Esters of allylic alcohols with resin-bound carboxylic acids can be converted into allyl palladium complexes, which react with carbon nucleophiles and with hydride sources to yield the formally reduced allyl derivatives (Entries 3 and 4, Table 3.47). Alkyl sulfonates have been reduced to alkanes with NaBH4 (Entry 5, Table 3.47). Aryl sulfonates (Entry 6, Table 3.47) and aryl perfluoroalkylsulfonates [814] can be reduced to alkanes by treatment with catalytic amounts of Pd(II) and formic acid as a hydride source. 

The Suzuki coupling reaction is a powerful tool for carbon-carbon bond formation in combinatorial library production.23 Many different reaction conditions and catalyst systems have been reported for the cross-coupling of aryl triflates and aromatic halides with boronic acids in solution. After some experimentation, we found that the Suzuki cleavage of the resin-bound perfluoroalkylsulfonates proceeded smoothly by using [l,l -bis (diphenylphosphino)ferrocene]dichloropalladium(II), triethylamine, and boronic acids in dimethylformamide at 80° within 8 h afforded the desired biaryl compounds in good yields.24 The desired products are easily isolated by a simple two-phase extraction process and purified by preparative TLC to give the biaryl compounds in high purity, as determined by HPLC, GC-MS, and LC-MS analysis. 

Finally, 10 mol-% of the lanthanide perfluoroalkylsulfone amide complex Yb(N(S02C4F9)2)3 in QH5CF3 catalyzes both Friedel-Crafts acylation and the Diels-Alder reaction [26]. The high Lewis acidity of the metal complexes seems to be crucial. 

A perfluoroalkylsulfonate monomer can be synthesized from triethyl phosphite and hexafiuoroacetone to get in the first step ethyl pentafiuoroisopropenyl ether. Then the reaction with sulfur trioxide yields 2-ketopentafluoropropanesulfonic acid. Finally, N,N-... 

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