Sulfonation, degree

PEEK polymers are characterized by a high crystallinity which can be reduced by PEEK modified with cardo (Latin meaning loop) group which increase the amorphous degree. Sulfonated cardo-group modified PEEK (sPEEK-WC), as shown in Fig. 6.7, has been proposed for DMFC application [182-184]. A comprehensive review of the use of sPEEK and sPEEK-WC membranes in DMFC has been recently performed by lulianelli and Basile [185]. 

The aromatic rings of kraft lignins can be sulfonated to varying degrees with sodium sulfite at high temperatures (150—200°C) or sulfomethylated with formaldehyde and sulfite at low temperatures (<100° C). Oxidative sulfonation with oxygen and sulfite is also possible. 

Combination techniques such as microscopy—ftir and pyrolysis—ir have helped solve some particularly difficult separations and complex identifications. Microscopy—ftir has been used to determine the composition of copolymer fibers (22) polyacrylonitrile, methyl acrylate, and a dye-receptive organic sulfonate trimer have been identified in acryHc fiber. Both normal and grazing angle modes can be used to identify components (23). Pyrolysis—ir has been used to study polymer decomposition (24) and to determine the degree of cross-linking of sulfonated divinylbenzene—styrene copolymer (25) and ethylene or propylene levels and ratios in ethylene—propylene copolymers (26). 

Spkit Blue [2152-64-9] Cl Solvent Blue 23 (Cl 42760), is one of the few dyes sulfonated as the leuco base. The degree of sulfonation depends on the conditions. Monosulfonated derivatives, commonly referred to as alkaU blues, eg. Cl Acid Blue 119 [1324-76-17, are used as thek barium or calcium salts in printing inks. Disulfonated compounds, eg. Cl Acid Blue 48 [1324-77-2] are employed as thek sodium or ammonium salts for blueing paper, whereas the trisulfonic derivatives or ink blues, eg. Cl Acid Blue 93 [28983-56A] are used in writing inks (qv). 

The soluble azo dyes contain one or more sulfonic acid groups. Their degree of water solubiUty is determined by the number of sulfonic groups present and their position in the molecule. FD C Red No. 40 (5) and D C Orange No. 4 (16) belong in this class. 

For many secondary sulfonates, nucleophilic substitution seems to be best explained by a concerted mechanism with a high degree of carbocation character at the transition state. This has been described as an exploded transition state. Both the breaking and forming bonds are relatively weak so that the carbon has a substantial positive charge. However, the carbocation per se has no lifetime because bond breaking and fonnadon occur concurrently."... 

Although benzene-sulfonic acid, CnITsSChH, is a strong acid in aqueous solution, it is not completely dissociated in formic acid solution. In a 0.1-molal solution the degree of dissociation was estimated at 60 per cent.2 This is comparable with the dissociation of HIOs in aqueous solution and is compatible with J = 0.14 electron-volt for the formation of (HCOOH2)+. Using this value the level has been included in Fig. 65. 

Lignins are most usually employed as various types of sodium lig-nosulfonate and are products of sulfite pulping. (Kraft lignins from the Kraft pulping process are also available.) They are used as dispersants, binders, sequestrants, and emulsifiers. Sodium lignosulfonate product variables include color, MW, and the degree of carboxylation and sulfonation on the lignin backbone. 

Kelig 100 is a sodium lignosulfonate with a high degree of sulfonation and excellent sequestering properties, and it is compatible with almost all types of formulations. 

Other chemistries include acrylic acid/sodium 3-allyloxy-2-hydroxypropane sulfonate (AA/COPS), such as Aquatreat AR-540 and its newer derivative, having a higher degree of sulfonation, acrylic acid/non-ionic aromatic and linear sulfonate (AA/NI-AS-LS), Aquatreat AR-550. 

The stereoselective conjugate addition of lithium (Z)-dialkenylcuprates to vinyl sulfones gives (Z)-olefms in the range of 70-80% overall yield and no ( )-isomer is detected (equation 66)56. The degree of stereoselectivity is higher than 90%. 

Roberts et al. [131,132] investigated the formation of sultones in the production of AOS. In the initial sulfonation stage, these include 1,2-, 1,3-, and 1-4-sultones. As indicated earlier, the 1,2 and 1,3 derivatives are easily hydrolyzed to produce sulfonates. The 1,4-sultone (8 sultone) is fairly resistant to saponification, and severe conditions are required for complete conversion to sulfonates. The presence, then, of 1,4-sultone is an indication of the degree of hydrolysis. 

Fujiwara et al. used the CMC values of sodium and calcium salts to calculate the energetic parameters of the micellization [61]. The cohesive energy change in micelle formation of the a-sulfonated fatty acid methyl esters, calculated from the dependency of the CMC on the numbers of C atoms, is equivalent to that of typical ionic surfactants (Na ester sulfonates, 1.1 kT Ca ester sulfonates, 0.93 kT Na dodecyl sulfate, 1.1 kT). The degree of dissociation for the counterions bound to the micelle can be calculated from the dependency of the CMC on the concentration of the counterions. The values of the ester sulfonates are also in the same range as for other typical ionic surfactants (Na ester sulfonates, 0.61 Ca ester sulfonates, 0.70 Na dodecyl sulfate, 0.66). 

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