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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

The desulfurization of organic trisulfides : a mechanistic study

Smith, Roger Astbury. January 1979 (has links)
Many aspects of the desulfurization of trisulfides have been investigated. Efforts directed toward the syntheses of cyclic trisulfides provided mixtures of oligomers or the corresponding disulfide. Radiochemically labelled trisulfides and an optically active trisulfide have been desulfurized by a variety of phosphines. Triarylphosphines preferentially removed the central sulfur atom under all conditions, while tris(dialkylamino)phosphines exhibited preferential terminal sulfur removal in low polarity solvent with a trend to increased central sulfur removal with increased solvent polarity. Exchange phenomena were examined and a mechanistic rationalization presented. Desulfurization by triarylphosphines was concluded to proceed by the rate-determining decomposition of a phosphonium salt to form products, while desulfurization by tris(dialkylamino)phosphines was considered to have phosphonium salt formation as the rate-determining step. / The reaction of trisulfides with trialkyl phosphites to give a mixture of unsymmetrical and symmetrical disulfides has been studied. Mechanistic and synthetic aspects are described. / The spontaneous desulfurization of sulfenic sulfonic thioanhydrides and exchange of the thiosulfonate products in polar solvents were examined.
12

The synthesis of chiral organosul fur and phosphorus compounds /

Friedlander, Barry Terence. January 1980 (has links)
A general route to optically active organosulfur and phosphorus compounds was investigated. Sulfinimides incorporating camphorimide were synthesized directly from a sulfinyl chloride and N-(trimethylsilyl)camphorimide. The diastereomers were found to be inseparable by crystallization or chromatography, although in one case an optically active sulfinamide was prepared by an asymmetric synthesis. / The phosphorus-imide bond was formed by coupling of an asymmetric phosphinous chloride and N-(trimethylsilyl)camphorimide. Addition of sulfur gave N-(phosphinothioyl)camphorimides as separable diastereomers. These were converted into optically active thiophosphoryl compounds which were chiral only at phosphorus. The absolute configurations of the diastereomers were obtained by single-crystal X-ray analysis, through NMR techniques and by conversion into phosphinothioic acids. / Displacement of camphorimide was effected with organometallic reagents, alcohols and thiols to give optically active phosphine sulfides, phosphinothionates and phosphinodithioates respectively. Optical yields of the products were dependant on the reagents and reaction conditions used. Mechanistic rationales are presented to account for the stereochemical results.
13

The hydrolysis of 1-acyl-2-thiohydantoins & related compounds.

Congdon, Wayne Irving. January 1970 (has links)
No description available.
14

Vapor-phase catalytic oxidesulfurization (ods) of organosulfur compounds over supported metal oxide catalysts /

Choi, Sukwon, January 2004 (has links)
Thesis (Ph. D.)--Lehigh University, 2005. / Includes vita. Includes bibliographical references.
15

Organosulfur derivatives of cyclopentadienylmetal carbonyls

Brauner, Michael Robert, January 1966 (has links)
Thesis (M.S.)--University of Wisconsin--Madison, 1966. / eContent provider-neutral record in process. Description based on print version record.
16

The hydrolysis of 1-acyl-2-thiohydantoins & related compounds.

Congdon, Wayne Irving. January 1970 (has links)
No description available.
17

The desulfurization of organic trisulfides : a mechanistic study

Smith, Roger Astbury. January 1979 (has links)
No description available.
18

The synthesis of chiral organosul fur and phosphorus compounds /

Friedlander, Barry Terence. January 1980 (has links)
No description available.
19

SYNTHETIC AND MECHANISTIC STUDIES ON THE ELECTROOXIDATION OF ORGANIC THIOETHERS.

PETSOM, AMORN. January 1987 (has links)
This research has been directed at the study of neighboring group participation in electrooxidation of thioethers. Controlled potential oxidation of substituted 1,3-dithiane in wet acetonitrile provides substituted 1,2-dithiolane 1-oxide in good yield. Thioethers appended with neighboring alcohols and carboxylate are catalytically oxidized in a redox cycle by bromide ion. The formation of the alkoxysulfonium salt intermediates in such reactions is confirmed by product study. On the other hand, the acyloxysulfonium salt intermediates in the electrooxidation of endo -6-methylthio-bicyclo [2.2.1] heptane-2- endo -carboxylic acid (1) are unstable at room temperature. Control experiments using ¹⁸O labeled compounds prove unequivocally the existent of the acyloxysulfonium salt intermediates. Diastereospecific oxidation of 1 and its methyl ester with DABCO.2Br₂ complex and m-CPBA is sterically controlled. In both cases, similar product ratios are observed which is explained by the participation of the carboxylic acid group in the case of DABCO.2Br₂ oxidation but not in the case of m-CPBA oxidation. The structure of one of the diastereomer of the endo acid sulfoxide is unequivocally proved by x-ray crystallographic analysis.
20

The chemistry of organic disulfides; desulfurizations with aminophosphines.

Gleason, John Gerald. January 1970 (has links)
No description available.

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