Organosulfur compounds, determination

Adsorption on XAD-2 and XAD-4 resins followed by solvent desorption and head space GS has been employed for the preconcentration and determination of volatile organosulfur compounds in estuary and seawater [330]. 

Although many previous reviews (5-12) and literature compilations (13-16) have dealt with sulfur stereochemistry, we decided to write a new report on chiral sulfur compounds to provide a survey of the topic with emphasis on the most recent findings. This chapter consists of four major parts treating syntheses of chiral sulfur compounds, methods for determination of their absolute configuration and optical purity, the dynamic stereochemistry of organosulfur compounds, and the use of chiral sulfur compounds in asymmetric synthesis. 

As in the case of other chiral compounds, the optical and enantiomeric purity of chiral organosulfur compounds can be determined by various methods (241). The simplest and most common method for the determination of optical purity of a mixture of enantiomers is based on polarimetric measurements. However, this method requires a knowledge of the specific rotation of the pure enantiomer. In the... 

Organosulfur chemistry is presently a particularly dynamic subject area. The stereochemical aspects of this field are surveyed by M. Mikojajczyk and J. Drabowicz. in the fifth chapter, entitled Qural Organosulfur Compounds. The synthesis, resolution, and application of a wide range of chiral sulfur compounds are described as are the determination of absolute configuration and of enantiomeric purity of these substances. A discussion of the dynamic stereochemistry of chiral sulfur compounds including racemization processes follows. Finally, nucleophilic substitution on and reaction of such compounds with electrophiles, their use in asymmetric synthesis, and asymmetric induction in the transfer of chirality from sulfur to other centers is discussed in a chapter that should be of interest to chemists in several disciplines, in particular synthetic and natural product chemistry. 

Figure 24-20 Gas chromatograms showing sulfur compounds in natural gas (o) flame ionization detector response and (b) sulfur chemiluminescence detector response. The organosulfur compounds are too dilute to be seen in flame ionization, and the sulfur chemiluminescence is insensitive to hydrocarbons. [From N. G. Johansen and J. W. Birks, Determination of Sulfur Compounds in Difficult Matrices." Am. Lob. February 1991.112.]...

Methanesulfonic acid, dimethyl sulfoxide and dimethyl sulfone are potential intermediates in the gas phase oxidation of dimethylsulfide in the atmosphere. We nave measured the rate of reaction of MSA with OH in aqueous solution using laser flash photolysis of dilute hydrogen peroxide solutions as a source of hydroxyl radicals, and using competition kinetics with thiocyanate as the reference solute. The rate of the reaction k (OH + SCN ) was remeasured to be 9.60 1.12 x 109 M 1 s 1, in reasonable agreement with recent literature determinations. The rates of reaction of the hydroxyl radical with the organosulfur compounds were found to decrease in the order DMSO (k = 5.4 0.3 x 109 M-i s 1) > MSA (k = 4.7 0.9 x 107 M l S 1) > DMS02 (k = 2.7 . 15 x 107 M 1 s ). The implications of the rate constant for the fate of MSA in atmospheric water are discussed. 

During pyrolysis, H2S could be formed from the reaction of pyrite with hydrocarbons, hydrogen, or water, and from cracking of organosulfur compounds. Our objective was to determine the importance of these various reactions and to report the amounts of H2S evolved from oil-shale samples obtained from locations in Colorado. 

Bates, T.S. and Carpenter, R., 1979a. Determination of organosulfur compounds extracted from marine sediments. Anal. Chem., 51 551—554. 

Clark, A.J. (1993) Determination of organosulfur compounds and amino acid-mustard conjugates by liquid chromatography with amperometric detection. Anal. Proc. 30, 355-357. 

Ichikawa M., Ide N., Yoshida J., Yamaguchi H., Ono K. Determination of seven organosulfur compounds in garlic by high-performance liquid chromatography. Journal of Agricultural and Food Chemistry, 54 1535-1540 (2006). 

Ash determination gives a measure of gross cation level. In the case of sulfates and sulfonates, the ash will consist mainly of sodium sulfate, both from sulfate originally present and sulfate formed as a combustion product of the organosulfur compounds. The ash may be subjected to qualitative analysis by X-ray fluorescence or emission spectroscopy to determine whether other ions are present. A general procedure for ash determination is given in ASTM D482 (39). 

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