Sulfide, ethyl methyl chlorination

The woik of Tuleen and Stevens on the regioselectivity of chlorination of a series of unsymmetrically substituted dialkyl sulfides with NCS provides clues to Ae directive effects implicit in the mechanisms encompassed by Scheme 3. These observations are collected in Scheme 6 where the preferred site of chlorination in each case is indicated with an arrow, the number over the arrow indicating the majortminor product ratio (minor = 1). In the first example, chlorination of benzyl methyl sulfide (2) produces chlorobenzyl methyl sulfide exclusively. Secondly, chlorination of benzyl ethyl sulfide (3) and benzyl isopropyl sulfide (4) also shows a marked, though not exclusive, preference for the benzylic position. In the latter case the extent of benzylic chlorination can be modulated by ring substitution. The directive effects in these internal competitions for p-methyl and p-chloro substituents are correlated by the Hammett relationship with a value of p = 1.0, which is consistent with a mechanism involving abstraction of the more acidic proton in the chlorosulfonium ion intermediate. Further indications of the im-... [Pg.210]

MC MDI MEKP MF MMA MPEG MPF NBR NDI NR OPET OPP OSA PA PAEK PAI PAN PB PBAN PBI PBN PBS PBT PC PCD PCT PCTFE PE PEC PEG PEI PEK PEN PES PET PF PFA PI PIBI PMDI PMMA PMP PO PP PPA PPC PPO PPS PPSU Methyl cellulose Methylene diphenylene diisocyanate Methyl ethyl ketone peroxide Melamine formaldehyde Methyl methacrylate Polyethylene glycol monomethyl ether Melamine-phenol-formaldehyde Nitrile butyl rubber Naphthalene diisocyanate Natural rubber Oriented polyethylene terephthalate Oriented polypropylene Olefin-modified styrene-acrylonitrile Polyamide Poly(aryl ether-ketone) Poly(amide-imide) Polyacrylonitrile Polybutylene Poly(butadiene-acrylonitrile) Polybenzimidazole Polybutylene naphthalate Poly(butadiene-styrene) Poly(butylene terephthalate) Polycarbonate Polycarbodiimide Poly(cyclohexylene-dimethylene terephthalate) Polychlorotrifluoroethylene Polyethylene Chlorinated polyethylene Poly(ethylene glycol) Poly(ether-imide) Poly(ether-ketone) Polyethylene naphthalate Polyether sulfone Polyethylene terephthalate Phenol-formaldehyde copolymer Perfluoroalkoxy resin Polyimide Poly(isobutylene), Butyl rubber Polymeric methylene diphenylene diisocyanate Poly(methyl methacrylate) Poly(methylpentene) Polyolefins Polypropylene Polyphthalamide Chlorinated polypropylene Poly(phenylene oxide) Poly(phenylene sulfide) Poly(phenylene sulfone)... [Pg.959]

Little preparative importance attaches to conversion of organic sulfides into chloro compounds The fission of compounds R-S-R by chlorine, bromine, cyanogen bromide, and methyl iodide, with replacement of C-S by C-halogen bonds has been reviewed by Tarbell and Harnish.1287 The action of 1 mole of bromine on thioacetals in an anhydrous medium (ether) at room temperature affords bromo hemiacetals (a-bromo sulfides) and a sulfenyl bromide, and bromo sugars analogously from ethyl thioglycosides. [Pg.271]

Clinical samples of urine, blood, expired air, and tissue have been examined using headspace sampling approaches. Thus, chlorinated organic compounds, methanol, acetone, methyl ethyl ketone, and phenols have been determined in urine. Volatile substances in urine have also been used as a guide to acute poisoning, and the determination of stimulants in urine has been proposed as screening test for field use. The determination of the concentration of blood alcohol is the most well-known application of headspace techniques to biological samples. Blood has also been examined for cyanide, methyl sulfide, and formaldehyde levels, the last as a measure of methanol intoxication. The headspace approach for blood samples overcomes the difficulties associated with the alternative direct injection of two-phase samples. [Pg.2049]