- Isotope Effects on 31P Nuclear Shielding in Thiophosphites
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The 34S isotope effect on the chemical shift of PIII nuclei in P(SR)3 esters is close to 20.6 ppb per PIII-34S bond, i.e. 3-4 times larger than for thiolo sulphur atoms in S=P(SR)3.A similar behaviour is noted for the P(-S-)3 sites in P4S9 and P4S3 and for the downfield triplet of P4S8, which, accordingly, is assigned to the tri-coordinate P atoms of this sulphide. 13C isotope effects are also reported for trialkyl(aryl) phosphorotrithioites and S,S,S-phosphorotrithioates.
- Demarcq, Michel C.,Gleut, Louis Le,Hemelryck, Bruno G. Van
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p. 231 - 237
(2007/10/02)
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- Processes for the production of sulphur-containing esters of phosphoric acid and phosphorous acid
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Trithio- and tetrathiophosphates with mercaptocarboxylic acid derivatives are preeminently suitable as extreme pressure additives for lubricants. They reduce signs of wear and have no or only an insignificant corrosive action on the parts to be protected. They are obtained in high yields, shorter reaction times and relatively free from by-products via the trithiophosphites by reaction of phosphorus trihalides with mercaptans in the presence of a catalyst and subsequent oxidation with sulphur or an oxygen donor.
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