25291-17-2Relevant articles and documents
Parahydrogen-induced polarization transfer to 19F in perfluorocarbons for 19F NMR spectroscopy and MRI
Plaumann, Markus,Bommerich, Ute,Trantzschel, Thomas,Lego, Denise,Dillenberger, Sonja,Sauer, Grit,Bargon, Joachim,Buntkowsky, Gerd,Bernarding, Johannes
, p. 6334 - 6339 (2013)
Fluorinated substances are important in chemistry, industry, and the life sciences. In a new approach, parahydrogen-induced polarization (PHIP) is applied to enhance 19F MR signals of (perfluoro-n-hexyl)ethene and (perfluoro-n-hexyl)ethane. Unexpectedly, the end-standing CF3 group exhibits the highest amount of polarization despite the negligible coupling to the added protons. To clarify this non-intuitive distribution of polarization, signal enhancements in deuterated chloroform and acetone were compared and 19F-19F NOESY spectra, as well as 19F T 1 values were measured by NMR spectroscopy. By using the well separated and enhanced signal of the CF3 group, first 19F MR images of hyperpolarized linear semifluorinated alkenes were recorded. Copyright
SYNTHESE DE PERFLUORO-nHEXYL-2 ETHANOL C6F13C2H4OH PAR REDUCTION ELECTROCHIMIQUE SUR FIBRES DE CARBONE DE PERFLUORO-nHEXYL-2 IODO-1 ETHANE C6H13C2H4I DANS LE SOLVANT N,N DIMETHYLFORMAMIDE
Benefice-Malouet, S.,Blancou, H.,Calas, P.,Commeyras, A.
, p. 245 - 260 (1988)
Electrochemical reduction of 2-perfluoro-nhexyl-1-iodo-ethane at a carbon fibre cathode, in N,N-dimethylformamide as solvent, leads to the perfluoro-nhexyl-2-ethanol with perfluoro-nhexyl-2-ethylene as the major by-product.A mechanism is proposed on the basis of results obtained from macro-scale electrolysis and a study of Linear Sweep Voltammetry.
Fluorinated imidazolium salts having liquid crystal characteristics
Zama, Isabella,Gorni, Giacomo,Borzatta, Valerio,Cassani, Maria Cristina,Crupi, Cristina,Di Marco, Gaetano
, p. 749 - 753 (2016)
A family of fluorinated imidazolium salts showing liquid–crystalline properties in a wide temperature range was developed. These fluorinated ionic liquid crystals, due to their intrinsic hydrophobicity, high thermal stability and good conductivity, are suitable candidates to be used as electrolytes in electrochemical devices such as Dye Sensitized Solar Cell (DSSC) or lithium batteries.
2-(Perfluoroalkyl)ethanols by thermal alkylation of ambidentate lactams with 2-(perfluoroalkyl)-1-iodoalkanes, in the presence of added water. A change in mechanism and stoichiometry of the reaction. Isolation of a water adduct of the lactim ether intermediate
Brace
, p. 6504 - 6516 (1996)
Thermal alkylation of amides by an alkyl halide gives alcohols and esters, and the intriguing behavior of ambidentate lactams in this reaction with 2-(perfluoroalkyl)-1-iodoethanes and lactam 2 is summarized in Scheme 1.2-(Perfluoroalkyl)ethanols (3) are the principal alkylation product, and there is obtained a range of coproducts in varying amounts. A lactim ether salt (6·HI) is the first reaction intermediate in a sequence of reactions. For δ-valerolactam (8) or ε-caprolactam (11), conversion to 3 falls precipitously and R(F)CH=CH2 (4) becomes a major product. However, when water is introduced, alkylation rate of 2 by iodoalkane 1 increases, the conversion to 3 and 4 decreases, and a new lactim ether salt, 7.HI (the water adduct of 6·HI), is formed. Conversion to 3 is suppressed because coproduct 2 is weakly basic and the equilibrium lies on the side of the basic amine salt (7·HI). The mass spectrum of 2-hydroxy-2-[[(2-(perfluorohexyl)ethyl]oxy]pyrrolidine (7) includes the parent ion and a fragment (m/z = 131) of the intact pyrrolidine ring with an attached hydroxy group. Basic hydrolysis of product mixtures containing 7·HI in a protic solvent gives a high yield of 3 and 2. The higher lactams, 8 or 11, with 1 and water give the lactam salts efficiently; yield of 4 is low and yield of 3, by subsequent reaction with base, is high. With water present, the reaction rates of 8 and 1 are greater than for 2 and 1; water increases both the alkylation step and the water displacement step. Improved homogeneity of reaction mixtures and a specific solvent effect in which water stabilizes the bipolar transition state may be responsible for improved rates and yields.
Quaternary ammonium ionic liquids containing fluorous ponytails: Competitive alkylation and elimination reactions of I(CH2) nRf (n = 2, 3) with tertiary amines
Alhanash, Hana B.,Brisdon, Alan K.
, p. 152 - 157 (2013)
The formation of quaternary ammonium iodides possessing a fluorine-containing chain has been investigated. Reactions of tertiary amines, such as i-PrMe2N and n-BuMe2N with I(CH2) n(CF2)m(CF3), (n = 2, m = 5 and 7) do not cleanly yield the anticipated quaternary ammonium halide salt, instead elimination occurs and [RMe2NH]I (R = i-Pr, n-Bu) and CH 2CH(CF2)m(CF3) are formed. This is confirmed by the crystallographic characterisation of [n-BuMe2NH]I which is found to adopt a micellar-type arrangement in the solid state. Increasing the spacer chain-length to n = 3 does result in the desired quaternary ammonium halide salts, [RMe2N(CH2) 3(CF2)m(CF3)]I, (m = 3, 7). Quaternisation of MeBuN((CH2)3C8F17) with 1-iodooctane gave the asymmetric quaternary ammonium salt possessing a fluorinated alkyl chain, [n-BuMeOctN((CH2)3C 8F17)]I. Unlike in previously studied perprotio systems, low symmetry ammonium systems possessing long fluorinated chains do not result in room temperature ionic liquids.
Study of the alkylation of chlorosilanes. Part III. Synthesis and reactivity of new fluorinated organolithium reagents
Boutevin, B.,Guida-Pietrasanta, F.,Ratsimihety, A.,Caporiccio, G.
, p. 53 - 58 (1995)
The effect of the structure of the fluoroalkyl group RFC2H4, where RF = CF3, C6F13 and (CF3)2CF, on the synthesis and reactivity of organolithium reagents RFC2H4Li towards trimethylchlorosilane, (CH3)3SiCl, and tris(fluoroalkyl)silanes R1R2R3SiF where R = RFC2H4, has been studied.As a result, new fluorinated organolithium reagents have been synthesized, as well as new silanes such as a tris(fluoroalkyl)fluorosilane, 2SiF(C2H4C6F13), and fluorinated tetraalkylsilanes such as C6F13C2H4Si(CH3)3 and 2Si(C2H4C6F13)(C2H4CF3).All the products have been characterized by 1H, 19F and 29Si NMR spectroscopy. - Keywords: Synthesis; Reactivity; Alkylation; Fluorinated organolithium reagents; NMR spectroscopy
Method for synthesizing perfluoroalkyl ethylene
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Paragraph 0028-0030, (2018/02/04)
The invention provides a method for synthesizing perfluoroalkyl ethylene. The method comprises the following steps: stirring and mixing perfluoroalkyl ethyl iodide and an inorganic base solution, adding a phase transfer catalyst, stirring and heating, performing elimination reaction at 0-100 DEG C, after the reaction is completed, cooling the reaction liquid to the room temperature, leaving to stand and layer, separating the liquid, and washing the organic phase at a lower layer, thereby obtaining the product perfluoroalkyl ethylene. The method is simple in operation process, gentle in reaction condition, simple in product purification, free of organic solvent, and low in cost and safe and environmentally friendly as the phase transfer catalyst can be recycled.
Siloxane based syntheses of fluorous ethenes and their tandem Heck reactions with aryl iodides
Csapo, Agnes,Rabai, Jozsef
, p. 79 - 85,7 (2020/09/16)
Perfluoroalkyl-ethenes (RfnCHCH2, 6a-c; a, n = 4; b, n = 6; c, n = 8) were prepared in good isolated yields (67-89%) and high purity (GC assay > 98%) from various fluorinated organosilanes in fluoride-anion assisted protodesilylation reactions. The environmentally more benign 'KF/NEt3/H2O' reagent combination introduced here was found as an effective substitute for the commonly used tetrabutylammonium- fluoride trihydrate (TBAF·3H2O) as a fluoride source. Fluorous styrenes ((E)-RfnCHCHAr, 8) were then prepared in good isolated yields (58-93%/iodoarene) and purities (GC assay > 95%) with the Pd(0) catalyzed Heck coupling of iodoarenes (Ar-I, 7) and perfluoroalkyl-ethenes generated in situ by the fluoride assisted cleavage of (β-perfluoroalkyl- α-iodo-ethyl)-siloxane ([RfnCH2CH(I)SiMe 2]2O, 3) precursors in DMF solution at elevated temperatures. They are accessible by the one-pot reaction of dimethylvinylchlorosilane (CH2CHSiMe2Cl, 2) and perfluoroalkyl iodides (Rfn-I, 1) as we reported earlier. Similarly, the radical chain addition of C8F17I to CH 2CHSi(OMe)3 (9) gave (β-perfluorooctyl-α-iodo- ethyl)-trimethoxysilane ([C8F17CH2CH(I)]Si(OMe) 3, 10) in good yield, which then was reacted with silica gel in dry toluene to obtain an SiO2-bonded (perfluorooctyl)ethene surrogate [silica(O)3SiCH(I)CH2C8F17, 11]. The fluoride assisted cleavage of 11 and tandem Heck reaction with iodobenzene afforded the appropriate cross-coupled product (E)-C8F 17CHCHPh.
PROCESS FOR PRODUCING FLUORINATED (METH)ACRYLIC ESTER
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Page/Page column 8-9, (2010/11/25)
A mixture of fluoroalkyl iodides of the formula C2F5(CF2CF2)nI ( n is an integer of ≥0) wherein the sum of such fluoroalkyl iodides of n=3 and n=4 contained is ≥85 mol% is provided. This mixture is subjected to an ethylene addition step and an esterification step, and C2F5(CF2CF2)nCH=CH2 and C2F5(CF2CF2)nCH2CH2OH are removed. Thus, there can be obtained a mixture of fluorine-containing (meth)acrylic esters of the formula C2F5(CF2CF2)nCH2CH2OCOCR1=CH2 (wherein R1 represents a hydrogen atom or a methyl group, and n is an integer of ≥0) wherein the content of impurities (namely, olefins of the formula C2F5(CF2CF2)nCH=CH2 and alcohols of the formula C2F5(CF2CF2)nCH2CH2OH) is low.
PROCESS FOR PRODUCING FLUORINATED ACRYLIC ESTER
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Page/Page column 6-7; 8-9, (2008/06/13)
A mixture of fluorine-containing acrylic esters represented by CF3(CF2)nCH2CH2OCOCR1=CH2 wherein R1 is a hydrogen atom, a methyl group or a halogen atom and "n" is an integer of at least zero is subjected to distillation under such conditions that the esters are not polymerized, so as to give a mixture of the esters with a less content of impurities (that is, olefins represented by CF3(CF2)nCH=CH2 and alcohols represented by CF3(CF2)nCH2CH2OH) at a high yield.
