Sulfonic acids, reaction with

A new method for the preparation of PEMs is based on cross-linking and by thermally activated bridging of the polymer chains with polyatomic alcohols through condensation reaction with sulfonic acid functions. This was applied to sulfonated poly(ether ether ketone) (SPEEK) and some of the membranes exhibited conductivity higher than 2 x 10 S cm at room temperature. The SPEEK may potentially find applications as PEM materials for fuel cells. 

Miscellaneous Reactions. Aromatic sulfonic acid derivatives can be nitrated using nitric acid [52583-42-3] HNO, ia H2SO4 (19). Sultones may be treated with hydrazine derivatives to give the corresponding ring-opened sulfonic acid (20). 

Reactions of sulfonic acid A-sodium A-chloroamides with heterocycles in organic synthesis, in particular in synthesis of natural compounds 99ZOR503. 

As reaction mechanism for the modified triester approach with sulfonic acid azolides as coupling agents, 1491 the following reactions have been suggested 1491 1471 1501 441 1511 in the case of a sulfonyltetrazole ... 

A commonly used and important reaction of sulfonic acids, or sulfonates, is their conversion to sulfonyl chlorides by treatment with phosphorus halides, or sometimes with thionyl chloride. Although it is easy to postulate mechanisms for this conversion, the exact path followed has never been determined. Similarly, although mechanisms can be suggested for other known reactions involving sulfonic acids, such as the cleavage of dialkyl ethers by anhydrous sulfonic acids (Klamann and Weyerstahl, 1965), or the formation of sulfones by treatment of an aromatic hydrocarbon with a mixture of sulfonic acid plus polyphosphoric acid (Graybill, 1967), nothing truly definitive is known about the details of the actual mechanisms of these reactions. 

The axial immobilization of chiral [Mn((S,S)-salen )j (where salen = (Si,Sj-NiN -bis(3,5-diR -salicylidene)-l,2-diRbethane-diamine R = Bu, R -R = -(CH2)4- R = Bu, R = Ph R = Pn, R R = -(CH2)4-) complexes was achieved by reaction of [Mn(salen )Cl] with sulfonic acid- or phenol-substituted crosslinked and insoluble polystyrene resins [45]. The resulting polymer-immobilized [Mn(salen )j complexes were active and enantioselective for the asymmetric epoxidation of... 

Both 6-alkanesulfanyl- and 6-alkanesulfonylpurines proved competent coupling partners in the palladium-catalyzed Suzuki reaction with boronic acids when an imidazolium carbene ligand was used <20050L1149>. The sulfones were found to be significantly more reactive (60 °C, THF) than the thioethers (90 °C, toluene) (Scheme 44). 

Similar good results were obtained with Fe3+ montmorillonite and zeolite Beta with sulfonic acids, chlorides, or anhydrides as reagents.278 Iron(III) chloride is also very effective in this reaction under microwave irradiation.279 Sulfonylation by sulfonic acids catalyzed by Nafion-H allows the synthesis of both symmetric and unsymmetric sulfones.280... 

Substitution of sulfonesJ Organoaluminum reagents, particularly vinyl- or alkynylalanes, undergo Lewis acid catalyzed substitution reactions with sulfones. Thus the vinylalane 2 reacts with the allylic sulfone 1 in the presence of A1C13 to... 

There have been a number of reports of improved selectivity with sulfonic acid resin catalysts compared with conventional liquid acid catalysts[6—9]. Various explanations have also been proposed. If mechanisms usually postulated for condensation reactions with liquid Br0nsted acid [10] and solid acid catalysts [11] are adopted, the sequence of steps shown in Fig. 2 could be considered for the condensation of MFC. Both mechanisms incorporate the essential features of known carbenium ion chemistry, i.t., electrophilic attack on the aromatic ring by polar carbenium ion intermediates. Note that MDU is formed by this attack on the benzene ring of MPC, while the N—benzyl compound by the attack on nitrogen atom. 

The synthesis of methyl /-butyl ether (MTBE) from isobutylene and methanol on TS-1 has been investigated. This reaction is catalyzed by acids and the industrial production is carried out with sulfonic acid resin catalysts. It has been reported that at 363-383 K the reaction proceeds in the presence of the acidic HZSM-5, but also on TS-1, which is much more weakly acidic. However, the characterization of the catalysts used is not completely satisfactory for instance, the IR spectra reported do not show the 960-cm 1 band that is always present in titanium-containing silicas. It is therefore possible that the materials with which the reaction has been studied are not pufe-phase TS-1. The catalytic activity for MTBE synthesis is, in any case, an interesting result, and further investigations with fully characterized catalysts are expected to provide a satisfactory interpretation of these results (Chang et al., 1992). 

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