Sulfonate Group Determination

Finally, the sulfonate content of lignin is deterrnined by two main methods one typified by conductometric titration in which sulfonate groups are measured direcdy, and the other which measures the sulfur content and assumes that all of the sulfur is present as sulfonate groups. The method of choice for determining the sulfonate content of lignin samples that contain inorganic or nonsulfonate sulfur, however, is conductometric titration (45). 

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. 

The organic resin material is often a styrene divinylbenzene (DVB) copolymer in a network or matrix, to which are attached functional groups such as a sulfonic acid, carboxylic acid, and quaternary ammonium. The nature of these groups determines whether the resin is classified as a strong/weak acid (cation resin) or strong/weak base (anion resin) ion-exchanger. 

Comparison of results for the first and last entries in Table 7 (AOS 2024 and IOS 2024) was for samples for which the hydrophobe linearity, hydrophobe carbon number, and relative disulfonate content were held nearly constant. The major differences in these surfactants were possible differences in the relative locations of the double bond and the sulfonate group in the alkenesulfonate and in the relative locations of the hydroxy group and the sulfonate group in the hydroxyalkanesulfonate. Analyses to determine these are quite difficult. At calcium ion concentrations below 100-250 ppm, AOS 2024 appeared to be more salt-tolerant than linear IOS 2024. At higher calcium concentrations, the calcium ion tolerance of the two surfactants was similar. 

A highly linear internal olefinsulfonate IOS 2024 was then studied. The purpose was to determine whether the lower IOS 1518 adsorption noted above was due to a difference in hydrophobe branching, to different relative positions of the sulfonate group and the carbon-carbon double bond, or to different di monosulfonate ratios. 

These similarities indicate that the mechanism for (188) is apparently exactly the same as that for (135) except that the attack of water occurs on a sulfonyl group in (188), instead of on a sulfinyl group as in (135), and that a proton transfer is also part of the rate-determining step of the spontaneous hydrolysis of cr-disulfones. It may be recalled that in the case of the spontaneous hydrolysis of sulfinyl sulfones we determined that the purpose of the proton transfer was either to assist the attack of a water molecule on the substrate (136) or to assist the departure of the ArSOz group (137), but could not make a definite decision between the two alternatives from the information available. Thus the mechanism for the spontaneous hydrolysis of cr-disulfones is either as in (189) (where attack of water on a sulfonyl group is aided by the removal of a... 

The double bonds, carbonyl groups, carboxyl groups and large number of hydroxyl groups determine the physical and reaction behavior. In the case of lignosulfonates, the strongly acidic and polar sulfonic acid groups... 

A sulfone group incorporated within a l,l-dioxo-l,4-thiazine ring is also present in 6-(p-hydroxyphenyl)-2i/-3,4-dihydro-l,l-dioxo-l,4-thiazine (286), a compound obtained from the sponge Anchinoe tenacior [211], and in euthyroideones A-C (287-289), which are brominated quinone methides isolated from the New Zealand bryozoan Euthyroides episcopalis (order Cheilostomatida, suborder Ascophotina, family Euthyroididae) [212]. The spectral data of euthyroideone A (287), secured by X-ray analysis, was used for the structural determination of euthyroideones B (288) and C (289). Compound 288 showed a weak cytotoxic activity towards the BSC-1 cell line. 

The crystal and molecular structures of sodium l3-hydroxy-7-sulfonato-2-naphthoic add trihydrate and of l-hydroxy-4-sulfonato-2-naphthoic acid dihydrate have been determined, and their IR spectra and thermal behaviour studied.174 Each 3-hydroxy-7-sulfonato-2-naphthoic acid coordinates to two sodium ions through a bidentate sulfonate group and one oxygen atom of the carboxyl group, respectively. The other three sites in the coordination octahedron are occupied by water molecules. The l-hydroxy-4-sulfonato-2-naphthoic acid, as well as the bidentate sulfonate and monodentate carboxylate, also uses the oxygen atom of the hydroxyl group in coordinating the... 

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