OXIDATIVE HYDROLYSIS OF PHOSPHORUS(V) ESTERS OF THIOLS BY PEROXYMONOSULFATE ION. REACTIONS OF PEROXYMONOSULFATE ION WITH PHOSPHORUS(V) ESTERS OF THIOLS

✍ Scribed by Andrei Blaskó; Clifford A. Bunton; Anurag Kumar

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 172 KB
• Volume: 10
• Category: Article
• ISSN: 0894-3230
• DOI: 10.1002/(sici)1099-1395(199706)10:6<427::aid-poc900>3.0.co;2-6

✦ Synopsis

Peroxymonosulfate ion, HSO Ϫ 5 , as Oxone, readily converts phosphorus(V) esters of thiols into the phosphorus(V) and sulfonic acids. The esters were Ph 2 PO • SC 6 H 4 R(p) with R = MeO (1a), Me (1b), H (1c), Cl (1d) and NO 2 (1e), (EtO) 2 PO • SPh (2), Ph 2 OI • SEt (3) and PhPO(OEt)SEt (4). Reactions are first order in each reactant and second-order rate constants, k 2 , for 1a-e fit the Hammett equation with = Ϫ 0.46. The rate constants increase markedly with increasing water content of H 2 O-MeCN, the activation enthalpies are low and the entropies are negative. Despite the low value of ؊, these esters are much less reactive than thiol ethers, but the rate constants of reactions of these compounds and acyl thiols qualitatively follow the ionization potentials of the ethers and the esters.