34143-74-3Relevant articles and documents
Molecular baskets in supercritical CO2
Glennon, Jeremy D.
, p. 2207 - 2212 (1997)
Calixarenes are synthetic macrocyclic compounds, described as "molecular baskets" as they possess high ionophoric selectivity and form inclusion complexes with many important ionic guests. In our initial work, hexameric and tetrameric tert-butylcalixarenes, unfunctionalized at the lower rim, are shown to be separable on a diol column using supercritical fluid chromatography with methanol/chloroform-modified CO2 as mobile phase. The variation in capacity factors for these calixarenes was studied as a function of modifier composition. However, the solubility of these molecular baskets in unmodified supercritical CO2 is enhanced by fluorination at the upper rim. For example, when p-allylcalix[4]arene is derivatized by a thiol-ene addition reaction with heptadecafluorodecanethiol, CF3(CF2)7(CH2)2SH, a solubility of >0.12 mol L-1 in supercritical CO2 is measured for the p-heptadecafluorodecylthio-n-propylcalix[4]arene at 60 °C and 200 atm. However, subsequent lower rim functionalization to form the tetrahydroxamate derivative, while reducing the solubility, allows supercritical fluid extraction of Fe(III) by the fluorinated calix[4]arene ligands to be studied as a function of temperature and pressure and monitored using UV/visible and atomic absorption spectrometry. In particular, the visible absorption spectra obtained for the extracted Fe(III)-calix[4]arene tetrahydroxamate complex, collected in dimethyl sulfoxide, are indicative of octahedral Fe(III) complexation in a manner similar to that displayed by water-soluble siderophores. Studies on the efficiency and selectivity of Fe(III) extraction are also reported.
S-perfluoroalkyl substituted hydroxybenzylthioethers and derivatives as surface modifiers
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, (2010/01/31)
The invention describes a process for reducing the surface energy of organic materials such as for example increasing the oil and water repellency and stain release of organic materials, which comprises treating the organic material with at least a compound of the formula I wherein the general symbols are as defined in claim 1; especially wherein at least one of the radicals R2, R3 or R4 is —CH(R11)—S(O)p—R12; R11 is hydrogen, C1-C8alkyl, unsubstituted or with C1-C4alkyl substituted phenyl; R12 is a monovalent perfluorinated alkyl or alkenyl, linear or branched organic radical having four to twenty fully fluorinated carbon atoms, and p is 0, 1 or 2.
Free-radical addition of 2-(perfluoroalkyl)ethanethiols to alkenes, alkadienes, cycloalkenes, alkynes and vinyl monomers
Brace, Neal O.
, p. 217 - 241 (2007/10/02)
The free-radical addition of 2-(perfluoroalkyl)ethanethiols (RFCH2CH2SH) to alkenes, cycloalkenes, alkadienes and alkynes has been studied to determine: (1) the mode of reaction, i.e. the stereochemistry, regiochemistry and any skeletal changes: (2) the relative reactivity towards unsaturates of differing structures and classes as affected by the presence of the RF group; and (3) the influence of the reaction conditions on the rate of addition or selectivity for different products.Adducts from 2-(F-hexyl)ethanethiol (1) and alkenes have been obtained in high yield,but containing small amounts of regio isomers.For example compound 1 with 1-heptene gave 1-heptane (3, 96percent yield) as well as 2-heptane (4, O.61percent) and 3-heptane (5, 2.22percent). 1,6-Hexadiene and 1,7-octadiene gave chiefly linear adducts, i.e.RFCH2CH2S(CH2)nCH=CH2 (7, n=4; or 12, n=6, respectively) and RFCH2CH2S(CH2)nSCH2CH2RF (8, n=6; or 14, n=8, respectively).A small amount (2-3percent) of cis- and trans-1-methyl-cyclohexane (13) isomers were present in 12.Compound 1 with 1,6-heptadiene gave 7--1-heptene (9), the bis adduct, 1,7-bis-heptane (11) and the cyclic adducts, cis- and trans-1-methal-2-methylcyclopentane (10).The relative amounts of cyclic isomers depended on the reactant ratio.Compound 1 added readily with free-radical initiation to vinyl monomers such as styrene and vinyl acetate, and to phenyl acetylene, propargyl acetate and ethyl propynoate.These new addition products are useful as models for further study.