Sulfonate measurements

The calibration standards included sodium form polystyrene sulfonates obtained from Pressure Chemical Co., Pittsburgh, Pa., and sodium toluene sulfonate. Measurements were taken at 0.5 to I.Oml/mln flow rates. The logarithm of the molecular weight of the standards was linear it suggests a framework for approaching an interpretion of the structure of the scission products. This application of size exclusion chromatography measurements must be viewed as a first approximation because of the unmeasured differences between the chromatographic behavior of the linear standards and the expected branched structure of the scission products. 

Drifford M, Dalbiez JP. Effect of salt on sodium polystyrene sulfonate measured by light scattering. Biopolymers 1985 24 1501-1514. 

The PE spectrum of styryl methyl sulfone measured by Cauletti and coworkers59 is of similar complexity with its first and second bands assigned to ring n orbitals, namely 7t =9.08eV and 72 = 9.66eV (n2,a2). Colonna and coworkers60 also measured... 

Although intended for the biochemistry lab, this experiment provides analytical students with a practical characterization analysis. Of particular interest is the use of Job s method to determine the number of TNS (2-p-toludinylnaphthalene-6-sulfonate) binding sites on calmodulin, fluorescence is measured at 475 nm using an excitation wavelength of 330 nm. 

A iridine traces in aqueous solution can be determined by reaction with 4-(p-nitroben25l)pyridine [1083-48-3] and potassium carbonate [584-08-7]. Quantitative determination is carried out by photometric measurement of the absorption of the blue dye formed (367,368). Alkylating reagents interfere in the determination. A iridine traces in the air can be detected discontinuously by absorption in Folin s reagent (l,2-naphthoquinone-4-sulfonate) [2066-93-5] (369,370) with subsequent chloroform extraction and hplc analysis of the red dye formed (371,372). The detection limit is ca 0.1 ppm. Nitrogen-specific thermal ionisation detectors can be used for continuous monitoring of the ambient air. 

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). 

A further measure of improvement has resulted ia a cycHc process for the electrochemical syathesis of NH (196). The catalyst is /n j -W(N2)2(dppe)2 or less effectively its Mo analogue. The choice of acid is important so as to provide a ligand duriag part of the cycle, yet also an effective leaving group when the catalyst is reformed. A sulfonic acid is used. 

After the SO converter has stabilized, the 6—7% SO gas stream can be further diluted with dry air, I, to provide the SO reaction gas at a prescribed concentration, ca 4 vol % for LAB sulfonation and ca 2.5% for alcohol ethoxylate sulfation. The molten sulfur is accurately measured and controlled by mass flow meters. The organic feedstock is also accurately controlled by mass flow meters and a variable speed-driven gear pump. The high velocity SO reaction gas and organic feedstock are introduced into the top of the sulfonation reactor,, in cocurrent downward flow where the reaction product and gas are separated in a cyclone separator, K, then pumped to a cooler, L, and circulated back into a quench cooling reservoir at the base of the reactor, unique to Chemithon concentric reactor systems. The gas stream from the cyclone separator, M, is sent to an electrostatic precipitator (ESP), N, which removes entrained acidic organics, and then sent to the packed tower, H, where SO2 and any SO traces are adsorbed in a dilute NaOH solution and finally vented, O. Even a 99% conversion of SO2 to SO contributes ca 500 ppm SO2 to the effluent gas. 

The organic chemistry of sulfuryl chloride involves its use in chlorination and sulfonation (172,175,196,197). As a chlorinating agent, sulfuryl chloride is often mote selective than elemental chlorine. The use of sulfuryl chloride as a chlorinating agent often allows mote convenient handling and measurement as well as better temperature control because of the lower heat of reaction as compared with chlorine. Sulfuryl chloride sometimes affords better selectivity than chlorine in chlorination of active methylene compounds (198—200) ... 

Aminoisoxazoles can be determined photometrically by reaction with sodium 1,2-naph-thoquinone-4-sulfonate and selective extraction of the resulting dye into CCI4 for absorbance measurements. This class of compound can be determined in the presence of sulfonamides, sulfanilamides, hydroxylamines and other select amines (74MI41610). 

The solvolysis of 2, 35-3-(4-methoxyphenyl)but-2-yl/>-toluensulfonate in acetic acid can be followed by several kinetic measurements (a) rate of decrease of observed rotation (k ) rate of release of the leaving group (k,) and, when 0-labeled sulfonate is used, the rate of equilibration of the sulfonate oxygens (k ). At 25°C, the rate constants are... 

When the Dnseoc group is used in nucleoside synthesis, the coupling yields are determined by measuring the absorbance at 350 nm of each eluate from the Dnseoc-deprotection steps containing the 5-(dimethylamino)naphthalene-l-yl-vinyl sulfone or by measuring the fluorescence at 530 nm. ... 

The major problem of these diazotizations is oxidation of the initial aminophenols by nitrous acid to the corresponding quinones. Easily oxidized amines, in particular aminonaphthols, are therefore commonly diazotized in a weakly acidic medium (pH 3, so-called neutral diazotization) or in the presence of zinc or copper salts. This process, which is due to Sandmeyer, is important in the manufacture of diazo components for metal complex dyes, in particular those derived from l-amino-2-naphthol-4-sulfonic acid. Kozlov and Volodarskii (1969) measured the rates of diazotization of l-amino-2-naphthol-4-sulfonic acid in the presence of one equivalent of 13 different sulfates, chlorides, and nitrates of di- and trivalent metal ions (Cu2+, Sn2+, Zn2+, Mg2+, Fe2 +, Fe3+, Al3+, etc.). The rates are first-order with respect to the added salts. The highest rate is that in the presence of Cu2+. The anions also have a catalytic effect (CuCl2 > Cu(N03)2 > CuS04). The mechanistic basis of this metal ion catalysis is not yet clear. 

Quantitative studies based on kinetic measurements using strongly electrophilic diazonium ions and, as coupling components, 1-naphthol, 2-naphthol-6-sulfonic acid, and resorcinol in aqueous acid were made by Sterba and coworkers (Kropacova et al., 1970 Kavalek et al., 1970 Sterba and Valter, 1972 Machackova et al., 1972a). In a typical case (2,6-dichloro-4-nitrobenzenediazonium ion and 1-naphthol) the dependence of the logarithm of the measured rate constant (ks) on pH was linear with a slope of 1. At pH < 1, however, a practically constant value of ks was obtained. The measured rate constants therefore correspond to Scheme 12-62, in which the first term relates to the reaction of the naphthoxide ion and the second to that of the undissociated naphthol Ka is the acidity constant of 1-naphthol. 

Almost all of the directly measured thermochemical data for the sulfoxides, sulfones, sulfites and sulfates are due to the work of Busfield and Mackle and their coworkers at the University of Leeds and The Queens University, Belfast1-14. This work involved measurement of enthalpies of combustion, fusion and vaporization. It is the basis of the subsequent compilations of Benson and coworkers15, Cox and Pilcher16 and Pedley, Naylor and Kirby11. The data given by the latter are used as the basic data set in the present work. Corrections and omissions are noted in the next section. Data on additional compounds were sought by searching the IUPAC Bulletin of Thermochemistry and Thermodynamics for the years 1980 198318, and by searches of Chemical Abstracts. 

The thermochemical data for the sulfoxides, sulfones, sulfites and sulfates, derived from calorimetric measurements, are given in Tables 1-5. All entries in the tables were checked by examination of the original sources. Where available, data are given for the gas phase and either the liquid (lq) or solid (c) phase. Preference was given to gas and liquid phase data. 

Kunieda and coworkers186 measured the pKa values of substituted a-phenylsulfinylacetophenones XC6H4SOCH2COC6H4Y in 50% ethanol. The p values are 1.32 for X and 2.68 for Y. The former was compared with 2.01 in the analogous sulfone system (see above182) andit was suggested that the lower value for XC6H4SO was due to a smaller 7t(pd) interaction. 

The evidence presented so far excludes the formation of dissociated ions as the principal precursor to sulfone, since such a mechanism would yield a mixture of two isomeric sulfones. Similarly, in the case of optically active ester a racemic product should be formed. The observed data are consistent with either an ion-pair mechanism or a more concerted cyclic intramolecular mechanism involving little change between the polarity of the ground state and transition state. Support for the second alternative was found from measurements of the substituent and solvent effects on the rate of reaction. 

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