- Synthesis and surface activities of organic solvent-soluble fluorinated surfactants
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A variety of fluorinated surfactants soluble in organic solvent were prepared, including C8F17SO2NHCnH2n+1 (n = 2, 4, 6, 8, 10), C8F17SO2NHR (R = C6H11, C6H5), C8F17SO2N(CnH2n+1 )2 (n = 1, 2, 3, 4) and C8F17SO2NH(CH2)nN HO2SC8F17 (n = 6, 10). Their surface activities in various organic solvents were determined by surface tension measurement. The results showed that these fluorinated surfactants can reduce the surface tension of both polar and non-polar organic solvents. In general, organic solvents with strong polarity or long alkyl chain are beneficial to increase the surface activity of these polar fluorinated surfactants. By comparing fluorinated surfactants with the same fluorocarbon segment and connecting group, C8F17SO2N(CnH2n+1 )2 (n = 1, 2, 3, 4) showed lower surface activity in organic solvents than C8F17SO2NHCnH2n+1 (n = 2, 4, 6, 8) with an equal carbon number of the solvophilic group. Through surface tension vs. concentration curves given for N-octyl perfluorooctanesulfonamide in various organic solvents, a break point like the critical micelle concentration of ordinary surfactants in aqueous solutions was observed, and the effect of the different types of organic solvents on adsorption and aggregation behavior was also studied.
- Li, Guo-Li,Zheng, Li-Qiang,Xiao, Jin-Xin
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experimental part
p. 674 - 681
(2009/12/22)
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- Synthesis and structure of environmentally relevant perfluorinated sulfonamides
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Alkylated perfluorooctanesulfonamides are compounds of environmental concern. To make these compounds available for environmental and toxicological studies, a series of N-alkylated perfluorooctanesulfonamides and structurally related compounds were synthesized by reaction of the corresponding perfluoroalkanesulfonyl fluoride with a suitable primary or secondary amine. Perfluoroalkanesulfonamidoethanols were obtained from the N-alkyl perfluoroalkanesulfonamides either by direct alkylation with bromoethanol or alkylation with acetic acid 2-bromo-ethyl ester followed by hydrolysis of the acetate. N-Alkyl perfluorooctanesulfonamidoacetates were synthesized in an analogous way by alkylation of N-alkyl perfluoroalkanesulfonamides with a bromo acetic acid ester, followed by basic ester hydrolysis. Alternatively, N-alkyl perfluoroalkanesulfonamides can be alkylated with an appropriate alcohol using the Mitsunobu reaction. Perfluorooctanesulfonamide was synthesized from the perfluorooctanesulfonyl fluoride via the azide by reduction with Zn/HCl. All perfluorooctanesulfonamides contained linear as well as branched C8F17 isomers, typically in a 10:1 to 30:1 ratio. The crystal structures of N-ethyl and N,N-diethyl perfluorooctanesulfonamide show that the S-N bond has considerable double bond character. This double bond character results in a significant rotational barrier around the S-N bond (ΔG≠ = 62-71 kJ mol-1) and a preferred solid state and solution conformation in which the N-alkyl groups are oriented opposite to the perfluorooctyl group to minimize steric crowding around the S-N bond.
- Lehmler, Hans-Joachim,Rama Rao,Nauduri, Dhananjaya,Vargo, John D.,Parkin, Sean
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p. 595 - 607
(2008/02/07)
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- Method for exterminating termites
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A method for exterminating termites comprising using an entomopathogenic nematode together with an inset-growth regulator or a slow-acting insecticide, wherein insecticidal effects are reinforced compared with the cases using singly the entomopathogenic nematode and the insect-growth regulator or the slow-acting insecticide, respectively, and a bait station for exterminating termites that contains an entomopathogenic nematode with an insect-growth regulator or a slow-acting insecticide. According to the invention, emission of harmful chemicals to environment can be suppressed. The invention is nonpoisonous for human being and livestock, and is useful for indoor or outdoor extermination of termites.
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Addition of N-ethylamine to a perfluoroalkylsulfonic acid chloride RFSO2Cl has been studied, to obtain the corresponding perfluoroalkylsulfonamide RFSO2NHC2H5. First a two-step synthesis has been considered : transformation of the perfluoroalkylsulfonic acid chloride RFSO2Cl to the corresponding fluoride RFSO2F, and addition of N-ethylamine; the study of the first step is reported. Then, a sulfonamide one-step synthesis involving a fluoride catalysis, is described.
- Benefice-Malouet,Blancou,Teissedre,Commeyras
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p. 319 - 332
(2007/10/02)
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